TUBERCULOSIS
8:01 AM
Description
Tuberculosis (TB) is a contagious disease. Like the common cold, it spreads through the air. Only people who are sick with TB in their lungs are infectious. Tuberculosis (TB) is a potentially fatal contagious disease that can affect almost any part of the body but is mainly an infection of the lungs. It is caused by a bacterial microorganism, the tubercle bacillus or Mycobacterium tuberculosis. Although TB can be treated, cured, and can be prevented if persons at risk take certain drugs, scientists have never come close to wiping it out. Few diseases have caused so much distressing illness for centuries and claimed so many lives. There is also a group of organisms referred to as atypical tuberculosis. These involve other types of bacteria that are in the Mycobacterium family. Often, these organisms do not cause disease and are referred to a "colonizers," because they simply live alongside other bacteria in our bodies without causing damage. At times, these bacteria can cause an infection that is sometimes clinically like typical tuberculosis. When these atypical mycobacteria cause infection, they are often very difficult to cure. Often, drug therapy for these organisms must be administered for one and a half to two years and requires multiple medications.
1. Ninety five percent of tuberculosis (TB) cases occur in developing countries where co-infection with human immunodeficiency virus (HIV) is also common.
2. Between 19 and 43 % of the world’s population is infected with M.tuberculosis. In the United States, although the rate of TB infection has declined, 15 million people are infected with M. tuberculosis (2).
3. TB kills more people than any other infectious disease, including malaria and acquired immune deficiency syndrome (AIDS). Each year, more than 3 million people die and 8 million people develop disease (1).
4. High-risk groups are considered people living in urban areas, institutions (prisons, nursing homes), homeless, minorities, immigrants, drug users, people with immunosuppression or HIV, healthcare workers and others in close contact with infected individuals.
5. 8 to 10% of those infected with HIV develop TB.
6. Incidence in USA: Overall 7.4/100,0000. In high-risk groups: 32-100/100,000.
When infectious people cough, sneeze, talk or spit, they propel TB germs, known as bacilli, into the air. A person needs only to inhale a small number of these to be infected.
Left untreated, each person with active TB disease will infect on average between 10 and 15 people every year. But people infected with TB bacilli will not necessarily become sick with the disease. The immune system "walls off" the TB bacilli which, protected by a thick waxy coat, can lie dormant for years. When someone's immune system is weakened, the chances of becoming sick are greater.
a. Someone in the world is newly infected with TB bacilli every second.
b. Overall, one-third of the world's population is currently infected with the TB bacillus.
c. 5-10% of people who are infected with TB bacilli (but who are not infected with HIV) become sick or infectious at some time during their life. People with HIV and TB infection are much more likely to develop TB.
Global and regional incidence
The World Health Organization (WHO) estimates that the largest number of new TB cases in 2005 occurred in the South-East Asia Region, which accounted for 34% of incident cases globally. However, the estimated incidence rate in sub-Saharan Africa is nearly twice that of the South-East Asia Region, at nearly 350 cases per 100 000 population.
Tuberculosis spread much more widely in Europe when the industrial revolution began in the late nineteenth century. The disease became widespread somewhat later in the United States, because the movement of the population to large cities made overcrowded housing so common. When streptomycin, the first antibiotic effective against M. tuberculosis, was discovered in the early 1940s, the infection began to come under control. Although other more effective anti-tuberculosis drugs were developed in the following decades, the number of cases of TB in the United States began to rise again in the mid-1980s. This upsurge was in part again a result of overcrowding and unsanitary conditions in the poor areas of large cities, prisons, and homeless shelters. Infected visitors and immigrants to the United States also contributed to the resurgence of TB. An additional factor is the AIDS epidemic. AIDS patients are much more likely to develop tuberculosis because of their weakened immune systems. There still are an estimated 8 to 10 million new cases of TB each year worldwide, causing roughly 3 million deaths.
It is estimated that 1.6 million deaths resulted from TB in 2005. Both the highest number of deaths and the highest mortality per capita are in the Africa Region. The TB epidemic in Africa grew rapidly during the 1990s, but this growth has been slowing each year, and incidence rates now appear to have stabilized or begun to fall.
In 2005, estimated per capita TB incidence was stable or falling in all six WHO regions. However, the slow decline in incidence rates per capita is offset by population growth. Consequently, the number of new cases arising each year is still increasing globally and in the WHO regions of Africa, the Eastern Mediterranean and South-East Asia.
HIV and TB
HIV and TB form a lethal combination, each speeding the other's progress. HIV weakens the immune system. Someone who is HIV-positive and infected with TB bacilli is many times more likely to become sick with TB than someone infected with TB bacilli who is HIV-negative. TB is a leading cause of death among people who are HIV-positive. In Africa, HIV is the single most important factor contributing to the increase in incidence of TB since 1990.
WHO and its international partners have formed the TB/HIV Working Group, which develops global policy on the control of HIV-related TB and advises on how those fighting against TB and HIV can work together to tackle this lethal combination. The interim policy on collaborative TB/HIV activities describes steps to create mechanisms of collaboration between TB and HIV/AIDS programmes, to reduce the burden of TB among people and reducing the burden of HIV among TB patients.
Drug-resistant TB
Until 50 years ago, there were no medicines to cure TB. Now, strains that are resistant to a single drug have been documented in every country surveyed; what is more, strains of TB resistant to all major anti-TB drugs have emerged. Drug-resistant TB is caused by inconsistent or partial treatment, when patients do not take all their medicines regularly for the required period because they start to feel better, because doctors and health workers prescribe the wrong treatment regimens, or because the drug supply is unreliable. A particularly dangerous form of drug-resistant TB is multidrug-resistant TB (MDR-TB), which is defined as the disease caused by TB bacilli resistant to at least isoniazid and rifampicin, the two most powerful anti-TB drugs. Rates of MDR-TB are high in some countries, especially in the former Soviet Union, and threaten TB control efforts.
While drug-resistant TB is generally treatable, it requires extensive chemotherapy (up to two years of treatment) with second-line anti-TB drugs which are more costly than first-line drugs, and which produce adverse drug reactions that are more severe, though manageable. Quality-assured second-line anti-TB drugs are available at reduced prices for projects approved by the Green Light Committee.
The emergence of extensively drug-resistant (XDR) TB, particularly in settings where many TB patients are also infected with HIV, poses a serious threat to TB control, and confirms the urgent need to strengthen basic TB control and to apply the new WHO guidelines for the programmatic management of drug-resistant TB.
High-risk populations
1. THE ELDERLY. Tuberculosis is more common in elderly persons. More than one-fourth of the nearly 23,000 cases of TB reported in the United States in 1995 developed in people above age 65. Many elderly patients developed the infection some years ago when the disease was more widespread. There are additional reasons for the vulnerability of older people: those living in nursing homes and similar facilities are in close contact with others who may be infected. The aging process itself may weaken the body's immune system, which is then less able to ward off the tubercle bacillus. Finally, bacteria that have lain dormant for some time in elderly persons may be reactivated and cause illness.
2. RACIAL AND ETHNIC GROUPS. TB also is more common in blacks, who are more likely to live under conditions that promote infection. As the end of the century approaches, two-thirds of all cases of TB in the United States affect African Americans, Hispanics, Asians, and persons from the Pacific Islands. Another one-fourth of cases affect persons born outside the United States. As of 1992, the risk of TB was still increasing in all these groups.
3. LIFESTYLE FACTORS. The high risk of TB in AIDS patients extends to those infected by human immunodeficiency virus (HIV) who have not yet developed clinical signs of AIDS. Alcoholics and intravenous drug abusers are also at increased risk of contracting tuberculosis. Until the economic and social factors that influence the spread of tubercular infection are remedied, there is no real possibility of completely eliminating the disease.
4. Alcoholism
5. Homelessness
6. Crowded living conditions
7. Diseases that weaken the immune system
8. Migration from a country with a high number of cases
9. Health-care workers
DIAGNOSIS
Clinical
1. Systemic symptoms of tuberculosis include anorexia, weight loss, weakness, night sweats, fatigability, malaise and fever.
2. Pulmonary TB presents with cough progressing from non- productive to productive and rarely, hemoptysis and dyspnea.
3. The majority of pulmonary TB infections in those with normal immune function are clinically and radiographically undetectable. A positive TB skin test is often the only indication of infection.
4. These latent infections, without active disease, are not infectious and the organism cannot be transmitted.
5. 10% of individuals with latent infection, if untreated, will develop active TB.
Laboratory
1. The gold standard for identifying M. tuberculosis infection without disease is the skin test with tuberculin purified protein derivative (PPD).
2. A 5-unit dose of PPD is 0.1 ml (1 mg) and should be applied intradermally.
3. Result interpretation at 48 to 72 hours by measuring the size of induration (2)
4. 5 mm - positive (in persons with HIV infection, immunosuppression, in close contact with infectious case or with radiological findings consistent with TB).
5. 10 mm - positive (in persons with risk factors: foreign born, IV drug use, low income, long term care facilities residents, medical conditions with risk of infection and age less than 4 years.
6. 15 mm - positive (in older than 4 years of age and no risk factors)(3)
7. Identification of organisms is critical in the diagnosis of tuberculosis.
8. Clinical specimens for detection of organisms may include sputum, bronchial washings, urine, blood, cerebrospinal fluid, tissue and other body fluids (2).
9. Acid-fast bacilli (AFB) in stained smears is evidence of Mycobacteria presence; easy and fast; is quantitative and can estimate degree of infectiousness: negative in up to 20% which does not rule out disease.
10. Culture: 4-6 weeks on solid media or 2 weeks on Bactec broth system.
At least 3 morning sputum samples (or other body fluid) are needed for AFB stain and culture.
11. Presumptive diagnosis is made through identification of AFB in smears and the diagnosis is confirmed when possible through isolation of the organism on culture
12. Polymerase chain reaction (PCR) is a rapid technique which allows for direct dentification of M. tuberculosis in clinical specimens.
13. Drug susceptibility tests of the infecting organism should be performed in order to determine resistance and the most effective treatment.
TREATMENT
• Therapy should always include multiple agents. It is best managed by and expert who works with the public health department. Directly Observed Therapy (DOT) is the most effective way to assure compliance.
• Isoniazid (INH) should be included in all treatment regimens except in cases of significant resistance to the drug.
• Rifampin (RMP) is the second major line of therapy.
• Isoniazid and Rifampin are bactericidal to both rapidly and slow growing TB organisms.
• Both pyrazinamide (PZA) and ethambutol are essential components of four-drug regimen therapy (Isoniazid, Rifampin, PZA, and Ethambutol) for resistant cases.
• Nine months of treatment with INH and RMP is effective for most cases of drug sensitive tuberculosis.
• Available second-line agents are more toxic and/or less efficacious (5).
FOLLOW-UP
• DOT (directly observed therapy): twice-weekly therapy (standard)
• Sputum for AFB: monthly
• CXR: at 3 months and at completion of therapy
• Not infectious if…clinical response after 2-3 weeks therapy and 3 negative AFB smears.
VACCINATION
• Bacillus of Calmette and Guerin (BCG) vaccine.
• Prevents progression to clinical disease not an infection.
• Not routinely used in the US or other industrialized nations due to the relatively low risk of infection in these areas.
• 60-80% effective in reducing the incidence of TB in children.
• May be useful in areas with high prevalence of TB infection.
• Administer only if tuberculin-negative.
• May be indicated for tuberculin-negative close contacts of a TB infected person who is untreated or ineffectively treated for pulmonary tuberculosis or who is infected with a drug resistant strain (4,5,6).
PREVENTION
1. TB prevention and control plans must be established in all health care settings and regularly evaluated for effectiveness
2. TB screening programs (PPDs) for all health care workers
3. Health care worker training and education
4. Use of preventive therapy (Isoniazid) to treat latent infection
5. Report suspected tuberculosis cases to the local health department
6. Use airborne isolation: until 2 (-) AFB smears from expectorated sputum. See policy for further instructions for discontinuing isolation.
7. Minimal air quality standard is 6-air exchanges/ hour (In 1 hour all droplet nuclei are removed from the air).
8. Identify and treat infectious cases to decrease transmission.
9. Reduce or eliminate conditions increasing the spread of infection (i.e. over crowding).
10. Educate the public regarding transmission, control methods and the importance of early diagnosis and treatment.
11. Adherence to prescribed therapy for tuberculosis should be emphasized and enforced (i.e. DOT) (4).
12. Quarantine is NOT necessary in most cases.
13. TB testing (PPD) of all close contacts. Chest x-rays should be performed on all with positive screening tests.
14. 3 months preventive treatment is recommended for close contacts who are skin test negative. Skin test should be repeated after 3 months to determine the need for further therapy (4).
Tuberculosis (TB) is a contagious disease. Like the common cold, it spreads through the air. Only people who are sick with TB in their lungs are infectious. Tuberculosis (TB) is a potentially fatal contagious disease that can affect almost any part of the body but is mainly an infection of the lungs. It is caused by a bacterial microorganism, the tubercle bacillus or Mycobacterium tuberculosis. Although TB can be treated, cured, and can be prevented if persons at risk take certain drugs, scientists have never come close to wiping it out. Few diseases have caused so much distressing illness for centuries and claimed so many lives. There is also a group of organisms referred to as atypical tuberculosis. These involve other types of bacteria that are in the Mycobacterium family. Often, these organisms do not cause disease and are referred to a "colonizers," because they simply live alongside other bacteria in our bodies without causing damage. At times, these bacteria can cause an infection that is sometimes clinically like typical tuberculosis. When these atypical mycobacteria cause infection, they are often very difficult to cure. Often, drug therapy for these organisms must be administered for one and a half to two years and requires multiple medications.
1. Ninety five percent of tuberculosis (TB) cases occur in developing countries where co-infection with human immunodeficiency virus (HIV) is also common.
2. Between 19 and 43 % of the world’s population is infected with M.tuberculosis. In the United States, although the rate of TB infection has declined, 15 million people are infected with M. tuberculosis (2).
3. TB kills more people than any other infectious disease, including malaria and acquired immune deficiency syndrome (AIDS). Each year, more than 3 million people die and 8 million people develop disease (1).
4. High-risk groups are considered people living in urban areas, institutions (prisons, nursing homes), homeless, minorities, immigrants, drug users, people with immunosuppression or HIV, healthcare workers and others in close contact with infected individuals.
5. 8 to 10% of those infected with HIV develop TB.
6. Incidence in USA: Overall 7.4/100,0000. In high-risk groups: 32-100/100,000.
When infectious people cough, sneeze, talk or spit, they propel TB germs, known as bacilli, into the air. A person needs only to inhale a small number of these to be infected.
Left untreated, each person with active TB disease will infect on average between 10 and 15 people every year. But people infected with TB bacilli will not necessarily become sick with the disease. The immune system "walls off" the TB bacilli which, protected by a thick waxy coat, can lie dormant for years. When someone's immune system is weakened, the chances of becoming sick are greater.
a. Someone in the world is newly infected with TB bacilli every second.
b. Overall, one-third of the world's population is currently infected with the TB bacillus.
c. 5-10% of people who are infected with TB bacilli (but who are not infected with HIV) become sick or infectious at some time during their life. People with HIV and TB infection are much more likely to develop TB.
Global and regional incidence
The World Health Organization (WHO) estimates that the largest number of new TB cases in 2005 occurred in the South-East Asia Region, which accounted for 34% of incident cases globally. However, the estimated incidence rate in sub-Saharan Africa is nearly twice that of the South-East Asia Region, at nearly 350 cases per 100 000 population.
Tuberculosis spread much more widely in Europe when the industrial revolution began in the late nineteenth century. The disease became widespread somewhat later in the United States, because the movement of the population to large cities made overcrowded housing so common. When streptomycin, the first antibiotic effective against M. tuberculosis, was discovered in the early 1940s, the infection began to come under control. Although other more effective anti-tuberculosis drugs were developed in the following decades, the number of cases of TB in the United States began to rise again in the mid-1980s. This upsurge was in part again a result of overcrowding and unsanitary conditions in the poor areas of large cities, prisons, and homeless shelters. Infected visitors and immigrants to the United States also contributed to the resurgence of TB. An additional factor is the AIDS epidemic. AIDS patients are much more likely to develop tuberculosis because of their weakened immune systems. There still are an estimated 8 to 10 million new cases of TB each year worldwide, causing roughly 3 million deaths.
It is estimated that 1.6 million deaths resulted from TB in 2005. Both the highest number of deaths and the highest mortality per capita are in the Africa Region. The TB epidemic in Africa grew rapidly during the 1990s, but this growth has been slowing each year, and incidence rates now appear to have stabilized or begun to fall.
In 2005, estimated per capita TB incidence was stable or falling in all six WHO regions. However, the slow decline in incidence rates per capita is offset by population growth. Consequently, the number of new cases arising each year is still increasing globally and in the WHO regions of Africa, the Eastern Mediterranean and South-East Asia.
HIV and TB
HIV and TB form a lethal combination, each speeding the other's progress. HIV weakens the immune system. Someone who is HIV-positive and infected with TB bacilli is many times more likely to become sick with TB than someone infected with TB bacilli who is HIV-negative. TB is a leading cause of death among people who are HIV-positive. In Africa, HIV is the single most important factor contributing to the increase in incidence of TB since 1990.
WHO and its international partners have formed the TB/HIV Working Group, which develops global policy on the control of HIV-related TB and advises on how those fighting against TB and HIV can work together to tackle this lethal combination. The interim policy on collaborative TB/HIV activities describes steps to create mechanisms of collaboration between TB and HIV/AIDS programmes, to reduce the burden of TB among people and reducing the burden of HIV among TB patients.
Drug-resistant TB
Until 50 years ago, there were no medicines to cure TB. Now, strains that are resistant to a single drug have been documented in every country surveyed; what is more, strains of TB resistant to all major anti-TB drugs have emerged. Drug-resistant TB is caused by inconsistent or partial treatment, when patients do not take all their medicines regularly for the required period because they start to feel better, because doctors and health workers prescribe the wrong treatment regimens, or because the drug supply is unreliable. A particularly dangerous form of drug-resistant TB is multidrug-resistant TB (MDR-TB), which is defined as the disease caused by TB bacilli resistant to at least isoniazid and rifampicin, the two most powerful anti-TB drugs. Rates of MDR-TB are high in some countries, especially in the former Soviet Union, and threaten TB control efforts.
While drug-resistant TB is generally treatable, it requires extensive chemotherapy (up to two years of treatment) with second-line anti-TB drugs which are more costly than first-line drugs, and which produce adverse drug reactions that are more severe, though manageable. Quality-assured second-line anti-TB drugs are available at reduced prices for projects approved by the Green Light Committee.
The emergence of extensively drug-resistant (XDR) TB, particularly in settings where many TB patients are also infected with HIV, poses a serious threat to TB control, and confirms the urgent need to strengthen basic TB control and to apply the new WHO guidelines for the programmatic management of drug-resistant TB.
High-risk populations
1. THE ELDERLY. Tuberculosis is more common in elderly persons. More than one-fourth of the nearly 23,000 cases of TB reported in the United States in 1995 developed in people above age 65. Many elderly patients developed the infection some years ago when the disease was more widespread. There are additional reasons for the vulnerability of older people: those living in nursing homes and similar facilities are in close contact with others who may be infected. The aging process itself may weaken the body's immune system, which is then less able to ward off the tubercle bacillus. Finally, bacteria that have lain dormant for some time in elderly persons may be reactivated and cause illness.
2. RACIAL AND ETHNIC GROUPS. TB also is more common in blacks, who are more likely to live under conditions that promote infection. As the end of the century approaches, two-thirds of all cases of TB in the United States affect African Americans, Hispanics, Asians, and persons from the Pacific Islands. Another one-fourth of cases affect persons born outside the United States. As of 1992, the risk of TB was still increasing in all these groups.
3. LIFESTYLE FACTORS. The high risk of TB in AIDS patients extends to those infected by human immunodeficiency virus (HIV) who have not yet developed clinical signs of AIDS. Alcoholics and intravenous drug abusers are also at increased risk of contracting tuberculosis. Until the economic and social factors that influence the spread of tubercular infection are remedied, there is no real possibility of completely eliminating the disease.
4. Alcoholism
5. Homelessness
6. Crowded living conditions
7. Diseases that weaken the immune system
8. Migration from a country with a high number of cases
9. Health-care workers
DIAGNOSIS
Clinical
1. Systemic symptoms of tuberculosis include anorexia, weight loss, weakness, night sweats, fatigability, malaise and fever.
2. Pulmonary TB presents with cough progressing from non- productive to productive and rarely, hemoptysis and dyspnea.
3. The majority of pulmonary TB infections in those with normal immune function are clinically and radiographically undetectable. A positive TB skin test is often the only indication of infection.
4. These latent infections, without active disease, are not infectious and the organism cannot be transmitted.
5. 10% of individuals with latent infection, if untreated, will develop active TB.
Laboratory
1. The gold standard for identifying M. tuberculosis infection without disease is the skin test with tuberculin purified protein derivative (PPD).
2. A 5-unit dose of PPD is 0.1 ml (1 mg) and should be applied intradermally.
3. Result interpretation at 48 to 72 hours by measuring the size of induration (2)
4. 5 mm - positive (in persons with HIV infection, immunosuppression, in close contact with infectious case or with radiological findings consistent with TB).
5. 10 mm - positive (in persons with risk factors: foreign born, IV drug use, low income, long term care facilities residents, medical conditions with risk of infection and age less than 4 years.
6. 15 mm - positive (in older than 4 years of age and no risk factors)(3)
7. Identification of organisms is critical in the diagnosis of tuberculosis.
8. Clinical specimens for detection of organisms may include sputum, bronchial washings, urine, blood, cerebrospinal fluid, tissue and other body fluids (2).
9. Acid-fast bacilli (AFB) in stained smears is evidence of Mycobacteria presence; easy and fast; is quantitative and can estimate degree of infectiousness: negative in up to 20% which does not rule out disease.
10. Culture: 4-6 weeks on solid media or 2 weeks on Bactec broth system.
At least 3 morning sputum samples (or other body fluid) are needed for AFB stain and culture.
11. Presumptive diagnosis is made through identification of AFB in smears and the diagnosis is confirmed when possible through isolation of the organism on culture
12. Polymerase chain reaction (PCR) is a rapid technique which allows for direct dentification of M. tuberculosis in clinical specimens.
13. Drug susceptibility tests of the infecting organism should be performed in order to determine resistance and the most effective treatment.
TREATMENT
• Therapy should always include multiple agents. It is best managed by and expert who works with the public health department. Directly Observed Therapy (DOT) is the most effective way to assure compliance.
• Isoniazid (INH) should be included in all treatment regimens except in cases of significant resistance to the drug.
• Rifampin (RMP) is the second major line of therapy.
• Isoniazid and Rifampin are bactericidal to both rapidly and slow growing TB organisms.
• Both pyrazinamide (PZA) and ethambutol are essential components of four-drug regimen therapy (Isoniazid, Rifampin, PZA, and Ethambutol) for resistant cases.
• Nine months of treatment with INH and RMP is effective for most cases of drug sensitive tuberculosis.
• Available second-line agents are more toxic and/or less efficacious (5).
FOLLOW-UP
• DOT (directly observed therapy): twice-weekly therapy (standard)
• Sputum for AFB: monthly
• CXR: at 3 months and at completion of therapy
• Not infectious if…clinical response after 2-3 weeks therapy and 3 negative AFB smears.
VACCINATION
• Bacillus of Calmette and Guerin (BCG) vaccine.
• Prevents progression to clinical disease not an infection.
• Not routinely used in the US or other industrialized nations due to the relatively low risk of infection in these areas.
• 60-80% effective in reducing the incidence of TB in children.
• May be useful in areas with high prevalence of TB infection.
• Administer only if tuberculin-negative.
• May be indicated for tuberculin-negative close contacts of a TB infected person who is untreated or ineffectively treated for pulmonary tuberculosis or who is infected with a drug resistant strain (4,5,6).
PREVENTION
1. TB prevention and control plans must be established in all health care settings and regularly evaluated for effectiveness
2. TB screening programs (PPDs) for all health care workers
3. Health care worker training and education
4. Use of preventive therapy (Isoniazid) to treat latent infection
5. Report suspected tuberculosis cases to the local health department
6. Use airborne isolation: until 2 (-) AFB smears from expectorated sputum. See policy for further instructions for discontinuing isolation.
7. Minimal air quality standard is 6-air exchanges/ hour (In 1 hour all droplet nuclei are removed from the air).
8. Identify and treat infectious cases to decrease transmission.
9. Reduce or eliminate conditions increasing the spread of infection (i.e. over crowding).
10. Educate the public regarding transmission, control methods and the importance of early diagnosis and treatment.
11. Adherence to prescribed therapy for tuberculosis should be emphasized and enforced (i.e. DOT) (4).
12. Quarantine is NOT necessary in most cases.
13. TB testing (PPD) of all close contacts. Chest x-rays should be performed on all with positive screening tests.
14. 3 months preventive treatment is recommended for close contacts who are skin test negative. Skin test should be repeated after 3 months to determine the need for further therapy (4).
Phobias
8:00 AM
A phobia is an intense, unrealistic fear, which can interfere with the ability to socialize, work, or go about everyday life, that is brought on by an object, event or situation.
Some people defined phobia as the unrelenting fear of a situation, activity, or thing that causes one to want to avoid it. A phobia is a type of anxiety disorder. Unlike the brief anxiety most people feel when they give a speech or take a test, a phobia is long-lasting, causes intense physical and psychological distress, and can affect your ability to function normally at work or in social settings.
Phobias are largely underreported, probably because many phobia sufferers find ways to avoid the situations to which they are phobic. Therefore, statistics that estimate how many people suffer from phobias vary widely, but at minimum, phobias afflict more than 6 million people in the United States. It is a strong, irrational fear of something that poses little or no actual danger. There are many specific phobias. Acrophobia is a fear of heights. You may be able to ski the world's tallest mountains but be unable to go above the 5th floor of an office building. Agoraphobia is a fear of public places, and claustrophobia is a fear of closed-in places. If you become anxious and extremely self-conscious in everyday social situations, you could have a social phobia. Other common phobias involve tunnels, highway driving, water, flying, animals and blood.
People with phobias try to avoid what they are afraid of. If they cannot, they may experience
• Panic and fear
• Rapid heartbeat
• Shortness of breath
• Trembling
• A strong desire to get away
The three kinds of phobias are social phobia (fear of public speaking, meeting new people or other social situations), agoraphobia (fear of being outside), and specific phobias (fear of particular items or situations). Some of the most common kinds of phobias include fears of public speaking or other social situations (social phobia or social anxiety disorder), open spaces (agoraphobia), closed-in spaces (claustrophobia), clowns (coulrophobia), flying (aerophobia), blood, animals (zoophobia), commitment (commitment phobia), driving, spiders (arachnophobia), needles (aichmophobia), snakes (ophidiophobia), math, heights (acrophobia or altophobia), germs (mysophobia), and having dental work done (dentophobia). Fears of midgets, haunted houses, helmets, pickles, and feet are just a few of the less common phobias and may be considered strange by some but can be just as debilitating as those phobias that are more common. Agoraphobia often coexists with panic disorder.
No matter what type of phobia you have, it's likely to produce the following reactions:
• A feeling of uncontrollable anxiety when you're exposed to the source of your fear sitting on an airplane, for instance, or walking into a large party
• The feeling that you must do everything possible to avoid what you fear
• The inability to function normally because of your anxiety
• Often, the knowledge that your fears are unreasonable or exaggerated but feeling powerless to control them
• Physical as well as psychological reactions, including sweating, rapid heartbeat, difficulty breathing, a feeling of panic and intense anxiety
• In some cases, anxiety just thinking about what you fear
Other facts about phobias include that these illnesses have been thought to affect up to 28 out of every 100 people, and in all western countries, phobias strike 7%-13% of the population. Women tend to be twice as likely to suffer from a phobia compared to men.
The most effect of Phobia such as :
1. If left untreated, a phobia may worsen to the point in which the person's life is seriously affected, both by the phobia itself and/or by attempts to avoid or conceal it.
2. In fact, some people have had problems with friends and family, failed in school, and/or lost jobs while struggling to cope with a severe phobia. There may be periods of spontaneous improvement, but a phobia does not usually go away unless the person receives treatments designed specifically to help phobia sufferers.
3. Alcoholics can be up to 10 times more likely to suffer from a phobia than those who are not alcoholics, and phobic individuals can be twice as likely to be addicted to alcohol than those who have never been phobic.
Much is still unknown about the actual cause of phobias. Studies seem to show a strong correlation between your own phobias and the phobias of your parents, however. Children may learn phobias by observing a family member's phobic reaction to an object or a situation — for example, a fear of snakes or spiders.
Brain chemicals, genetics and traumatic experiences also appear to influence the development of phobias.
Symptoms of phobias often involve having a panic attack -- in that they include feelings of panic, dread, or terror, despite recognition that those feelings are excessive in relationship to any real danger -- as well as physical symptoms like shaking, rapid heart beat, trouble breathing, and an overwhelming desire to escape the situation that is causing the phobic reaction. Also, extreme measures are sometimes taken to escape the situation.
Treatments and drugs
Your doctor or a mental health provider may suggest medications or behavior therapy or both to treat phobias. Most adults don't get better on their own and may require some type of treatment. The goal of phobia treatment is to reduce your anxiety and fear and to help you better manage your reactions to the object or situation that causes them.
Medications
• Beta blockers. These medications work by blocking the stimulating effects of adrenaline on your body, such as increased heart rate, elevated blood pressure, pounding heart, and shaking voice and limbs. Beta blockers can be very effective for people who have severe stage fright.
• Antidepressants. The most commonly used antidepressants are selective serotonin reuptake inhibitors (SSRIs). These medications act on the chemical serotonin, a neurotransmitter in your brain that's believed to influence mood. SSRIs include citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac), paroxetine (Paxil) and sertraline (Zoloft). If SSRIs aren't effective or cause intolerable side effects, your doctor may prescribe another type of antidepressant, such as a monoamine oxidase inhibitor (MAOI).
• Sedatives. Medications called benzodiazepines help you relax by reducing the amount of anxiety that you feel. They include lorazepam (Ativan), diazepam (Valium), alprazolam (Xanax) and chlordiazepoxide (Librium). Sedatives need to be used with caution because they can be addictive, and should be avoided if you have a history of alcohol or drug dependence.
Newer antidepressants are being specifically designed to target mechanisms that elevate serotonin and other neurotransmitters in the brain; some showing promise for anxiety are venlafaxine (Effexor) and nefazodone (Serzone). (Well-Connected) The antidepressant drugs known as tricyclic antidepressants (TCA) have also been effective in treating panic and obsessive-compulsive disorders (Well-Connected). The most common TCA used for the treatment of panic disorder is imipramine (Tofranil, Janimine); it is also effective in treating agoraphobia (Well-Connected). But with proper treatment, the vast majority of phobia patients can completely overcome their fears and be symptom free for years, if not for life (American).
Behavior therapy
Desensitization or exposure therapy focuses on changing your response to the object or situation that you fear. Gradual, repeated exposure to the cause of your phobia may help you learn to conquer your anxiety. For example, if you're afraid of flying, your therapy may progress from simply thinking about flying to looking at pictures of airplanes, to going to an airport, to sitting in an airplane, and finally to taking a flight.
Cognitive behavioral therapy is a more comprehensive form of therapy. It involves working with a therapist to learn ways to view and cope with the feared object or situation differently. You learn alternative beliefs about your fears and the impact they have on your life. There's special emphasis on learning to develop a sense of mastery and control of your thoughts and feelings.
Treatment choices
Specific phobias usually are treated with behavioral therapy. Social phobias may be treated with antidepressants or beta blockers, along with behavior therapy. Agoraphobia, especially when it's accompanied by a panic disorder, is usually treated with SSRIs and behavior therapy.
If you have unreasonable fears, consider getting psychological help. By dealing with your own fears, you won't pass them on to your children. In desensitization, three steps are involved:
1. Training the patient to physically relax
2. Establish an anxiety hierarchy of the stimuli involved
3. Counter-conditioning relaxation as a response to each feared stimulus beginning first with the least anxiety provoking stimulus and moving then to the next least anxiety provoking stimulus until all of the items listed in the anxiety hierarchy have been dealt with successfully (Phobia).
Also, systematic desensitization can be paired with modeling, and application suggested by social learning theorists (Phobia). In modeling, the patient observes others (the “model(s)”) in the presence of the phobic stimulus who are responding with relaxation rather that fear (Phobia). In this way, the patient is encouraged to imitate the model(s) and thereby relieve their phobia (Phobia). However relaxation therapy is not the only treatment used in curing phobias.
Hypnosis can also set you free of fears and phobias. In mild cases, where a person recognizes the triggers but would like help controlling their reaction, posthypnotic suggestions can help them control their breathing, slow their heart rate, and achieve a relaxed state of mind. This permits them to deal with the problem in a calm and rational manner. More severe cases are often the result of a traumatic childhood event. Most of the time the event can no longer be recalled by the conscious mind
Some people defined phobia as the unrelenting fear of a situation, activity, or thing that causes one to want to avoid it. A phobia is a type of anxiety disorder. Unlike the brief anxiety most people feel when they give a speech or take a test, a phobia is long-lasting, causes intense physical and psychological distress, and can affect your ability to function normally at work or in social settings.
Phobias are largely underreported, probably because many phobia sufferers find ways to avoid the situations to which they are phobic. Therefore, statistics that estimate how many people suffer from phobias vary widely, but at minimum, phobias afflict more than 6 million people in the United States. It is a strong, irrational fear of something that poses little or no actual danger. There are many specific phobias. Acrophobia is a fear of heights. You may be able to ski the world's tallest mountains but be unable to go above the 5th floor of an office building. Agoraphobia is a fear of public places, and claustrophobia is a fear of closed-in places. If you become anxious and extremely self-conscious in everyday social situations, you could have a social phobia. Other common phobias involve tunnels, highway driving, water, flying, animals and blood.
People with phobias try to avoid what they are afraid of. If they cannot, they may experience
• Panic and fear
• Rapid heartbeat
• Shortness of breath
• Trembling
• A strong desire to get away
The three kinds of phobias are social phobia (fear of public speaking, meeting new people or other social situations), agoraphobia (fear of being outside), and specific phobias (fear of particular items or situations). Some of the most common kinds of phobias include fears of public speaking or other social situations (social phobia or social anxiety disorder), open spaces (agoraphobia), closed-in spaces (claustrophobia), clowns (coulrophobia), flying (aerophobia), blood, animals (zoophobia), commitment (commitment phobia), driving, spiders (arachnophobia), needles (aichmophobia), snakes (ophidiophobia), math, heights (acrophobia or altophobia), germs (mysophobia), and having dental work done (dentophobia). Fears of midgets, haunted houses, helmets, pickles, and feet are just a few of the less common phobias and may be considered strange by some but can be just as debilitating as those phobias that are more common. Agoraphobia often coexists with panic disorder.
No matter what type of phobia you have, it's likely to produce the following reactions:
• A feeling of uncontrollable anxiety when you're exposed to the source of your fear sitting on an airplane, for instance, or walking into a large party
• The feeling that you must do everything possible to avoid what you fear
• The inability to function normally because of your anxiety
• Often, the knowledge that your fears are unreasonable or exaggerated but feeling powerless to control them
• Physical as well as psychological reactions, including sweating, rapid heartbeat, difficulty breathing, a feeling of panic and intense anxiety
• In some cases, anxiety just thinking about what you fear
Other facts about phobias include that these illnesses have been thought to affect up to 28 out of every 100 people, and in all western countries, phobias strike 7%-13% of the population. Women tend to be twice as likely to suffer from a phobia compared to men.
The most effect of Phobia such as :
1. If left untreated, a phobia may worsen to the point in which the person's life is seriously affected, both by the phobia itself and/or by attempts to avoid or conceal it.
2. In fact, some people have had problems with friends and family, failed in school, and/or lost jobs while struggling to cope with a severe phobia. There may be periods of spontaneous improvement, but a phobia does not usually go away unless the person receives treatments designed specifically to help phobia sufferers.
3. Alcoholics can be up to 10 times more likely to suffer from a phobia than those who are not alcoholics, and phobic individuals can be twice as likely to be addicted to alcohol than those who have never been phobic.
Much is still unknown about the actual cause of phobias. Studies seem to show a strong correlation between your own phobias and the phobias of your parents, however. Children may learn phobias by observing a family member's phobic reaction to an object or a situation — for example, a fear of snakes or spiders.
Brain chemicals, genetics and traumatic experiences also appear to influence the development of phobias.
Symptoms of phobias often involve having a panic attack -- in that they include feelings of panic, dread, or terror, despite recognition that those feelings are excessive in relationship to any real danger -- as well as physical symptoms like shaking, rapid heart beat, trouble breathing, and an overwhelming desire to escape the situation that is causing the phobic reaction. Also, extreme measures are sometimes taken to escape the situation.
Treatments and drugs
Your doctor or a mental health provider may suggest medications or behavior therapy or both to treat phobias. Most adults don't get better on their own and may require some type of treatment. The goal of phobia treatment is to reduce your anxiety and fear and to help you better manage your reactions to the object or situation that causes them.
Medications
• Beta blockers. These medications work by blocking the stimulating effects of adrenaline on your body, such as increased heart rate, elevated blood pressure, pounding heart, and shaking voice and limbs. Beta blockers can be very effective for people who have severe stage fright.
• Antidepressants. The most commonly used antidepressants are selective serotonin reuptake inhibitors (SSRIs). These medications act on the chemical serotonin, a neurotransmitter in your brain that's believed to influence mood. SSRIs include citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac), paroxetine (Paxil) and sertraline (Zoloft). If SSRIs aren't effective or cause intolerable side effects, your doctor may prescribe another type of antidepressant, such as a monoamine oxidase inhibitor (MAOI).
• Sedatives. Medications called benzodiazepines help you relax by reducing the amount of anxiety that you feel. They include lorazepam (Ativan), diazepam (Valium), alprazolam (Xanax) and chlordiazepoxide (Librium). Sedatives need to be used with caution because they can be addictive, and should be avoided if you have a history of alcohol or drug dependence.
Newer antidepressants are being specifically designed to target mechanisms that elevate serotonin and other neurotransmitters in the brain; some showing promise for anxiety are venlafaxine (Effexor) and nefazodone (Serzone). (Well-Connected) The antidepressant drugs known as tricyclic antidepressants (TCA) have also been effective in treating panic and obsessive-compulsive disorders (Well-Connected). The most common TCA used for the treatment of panic disorder is imipramine (Tofranil, Janimine); it is also effective in treating agoraphobia (Well-Connected). But with proper treatment, the vast majority of phobia patients can completely overcome their fears and be symptom free for years, if not for life (American).
Behavior therapy
Desensitization or exposure therapy focuses on changing your response to the object or situation that you fear. Gradual, repeated exposure to the cause of your phobia may help you learn to conquer your anxiety. For example, if you're afraid of flying, your therapy may progress from simply thinking about flying to looking at pictures of airplanes, to going to an airport, to sitting in an airplane, and finally to taking a flight.
Cognitive behavioral therapy is a more comprehensive form of therapy. It involves working with a therapist to learn ways to view and cope with the feared object or situation differently. You learn alternative beliefs about your fears and the impact they have on your life. There's special emphasis on learning to develop a sense of mastery and control of your thoughts and feelings.
Treatment choices
Specific phobias usually are treated with behavioral therapy. Social phobias may be treated with antidepressants or beta blockers, along with behavior therapy. Agoraphobia, especially when it's accompanied by a panic disorder, is usually treated with SSRIs and behavior therapy.
If you have unreasonable fears, consider getting psychological help. By dealing with your own fears, you won't pass them on to your children. In desensitization, three steps are involved:
1. Training the patient to physically relax
2. Establish an anxiety hierarchy of the stimuli involved
3. Counter-conditioning relaxation as a response to each feared stimulus beginning first with the least anxiety provoking stimulus and moving then to the next least anxiety provoking stimulus until all of the items listed in the anxiety hierarchy have been dealt with successfully (Phobia).
Also, systematic desensitization can be paired with modeling, and application suggested by social learning theorists (Phobia). In modeling, the patient observes others (the “model(s)”) in the presence of the phobic stimulus who are responding with relaxation rather that fear (Phobia). In this way, the patient is encouraged to imitate the model(s) and thereby relieve their phobia (Phobia). However relaxation therapy is not the only treatment used in curing phobias.
Hypnosis can also set you free of fears and phobias. In mild cases, where a person recognizes the triggers but would like help controlling their reaction, posthypnotic suggestions can help them control their breathing, slow their heart rate, and achieve a relaxed state of mind. This permits them to deal with the problem in a calm and rational manner. More severe cases are often the result of a traumatic childhood event. Most of the time the event can no longer be recalled by the conscious mind
Yaws
8:00 AM
Yaws is a tropical infection of the skin, bones and joints caused by the spirochete bacterium Treponema pertenue. Yaws is a contagious, nonvenereal, treponemal infection in humans that mainly occurs in children younger than 15 years. Infection with Treponema pertenue, a subspecies of Treponema pallidum, causes the disease, which occurs primarily in warm, humid, tropical areas of Africa, Asia, South America, and Oceania among poor rural populations where conditions of overcrowding and poor sanitation prevail. The sore appears as a "raspberry-like" growth or group of papules at the site of infection and is usually painless. These lesions may persist for months. Additional satellite lesions may appear shortly before or after the mother yaw heals. Children may also develop inflammation of the bones and fingers.
The final stage involves destructive lesions of the skin and bones which can lead to severe disfigurement and disability. It occurs in up to 20% of untreated individuals
Yaws tends to strike children, particularly between the ages of two and five. It is common in areas where poverty and overcrowding interfere with good hygiene practices. The most common locations are in rural areas throughout Africa, Southeast Asia, and in locations bordering the equator in the Americas.
Yaws is transmitted by direct contact with skin lesions of infected people. Approximately two to four weeks after infection, the child develops a sore "mother yaw" where the organism entered the skin.
If untreated a secondary stage occurs after up to four months of latency, it is marked by more 'raspberry' growths but smaller and ulcerous - exuding a thin, highly infective fluid which attracts flies. These growths may also merge together into thick fissured plaques, which can occur on the feet and induce a distinctive gait. These secondary growths are irreversible but there can be relapsing lesions and asymptomatic periods.
The major route of infection is through direct person-to-person contact. The treponemes associated with yaws are located primarily in the epidermis. The ulcerative skin lesions that develop early in the disease course are teeming with spirochetes, which can be transmitted via direct skin-to-skin contact and via breaks in the skin due to trauma, bites, or excoriations.
Yaws, like syphilis, has been classified into the following 4 stages:
1. Primary stage: The initial yaws lesion develops at the inoculation site.
2. Secondary stage: Widespread dissemination of treponemes results in multiple skin lesions similar to the primary yaws lesion.
3. Latent stage: Symptoms are usually absent, but skin lesions can relapse.
4. Tertiary stage: Bone, joint, and soft tissue deformities may occur.
Another classification distinguishes early yaws from late yaws. Early yaws includes primary and secondary stages and is characterized by the presence of contagious skin lesions. Late yaws includes the tertiary stage, when lesions are not contagious.
In 10-20% of cases the disease can progress over a decade or more to a tertiary stage with destructive lesions of the skin and bones. Large subcutaneous nodules develop and grow before abscessing and ulcerating, these can become infected and may merge together forming serpiginous tracts. These tracts heal with keloid formation which can cause deformities, disabilities and limb contractures. The bone lesions caused are periostitis, osteitis, and osteomyelitis, damage to the tibia can lead to a condition known as sabre shins. In a very few cases a condition known as goundou is caused where growths on the nasal maxillae can result in extensive and severe damage to the nose and palate.
Symptoms
Initial, single skin lesion that may grow slowly and have a raspberry-like appearance. It may also form an ulcer and is usually painless.
• Satellite lesions which may become large nodules/growths throughout the body and may have superficial erosions in secondary yaws.
• Fever may be present in secondary yaws.
• Bone pain/bone destruction; saber shins.
• Finger inflammation (dactylitis).
The first symptom of yaws occurs three to four weeks after acquiring the bacteria. The area where the bacteria originally entered the skin becomes a noticeable bump (papule). The papule grows larger and develops a punched-out center (ulcer), covered with a yellow crust. Lymph nodes in the area may become swollen and tender. This first papule may take as long as six months to heal. Secondary soft, gummy growths then appear on the face, arms and legs, and buttocks. These soft, tumor-like masses may grow on the soles of the feet, causing the patient to walk in an odd and characteristic fashion on the sides of his or her feet (nicknamed "crab yaws"). More destructive tumors may then disrupt the bones of the face, the jaw, and the lower leg. Ulcers around the nose and on the face may be very mutilating.
The largest group afflicted by Yaws are children aged 6 to 10 years in the Caribbean Islands, Latin America, West Africa, India, Oceania or Southeast Asia. There were World Health Organization funded campaigns against yaws from 1954 to 1963 which greatly reduced the incidence of the disease, although more recently numbers have risen again.
Mortality/Morbidity
• In most patients, yaws remains limited to the skin, but early bone and joint involvement can occur. Although yaws lesions disappear spontaneously, secondary bacterial infections and scarring are common complications.
• After 5-10 years, 10% of untreated patients develop destructive lesions that involve bone, cartilage, skin, and soft tissue, similar to those seen in tertiary syphilis. In contrast to venereal syphilis, cardiovascular and neurological abnormalities almost never occur in patients with yaws.
• Examination of ancient remains has led to the suggestion that yaws has affected hominids for the last 1.5 million years. The current name is believed to be of Carib origin, "yaya" meaning sore; frambesia is a Modern Latin word inspired by the French word framboise ("raspberry").
Exams and Tests
The diagnosis can be confirmed by examining a sample from a skin lesion under a special type of microscope (darkfield examination). There is no specific blood test for yaws, but because it is closely related to the bacterium that causes syphilis, the blood tests for syphilis may be positive in yaws as well. The disease is identified from blood tests or by a lesion sample through a darkfield examination under a microscope. Treatment is by a single dose of penicillin, erythromycin or tetracycline, recurrence or relapse is uncommon.
Treatment
The mainstay of treatment is a single dose of penicillin G. Relapse is rare. The goals of pharmacotherapy are to reduce morbidity and to prevent complications. Penicillin is rapidly effective in killing the spirochete and in curing yaws except in the tertiary stage, when oxophenarsine with bismuth subsalicylate is used. Prevention centres on isolating and promptly treating cases to reduce exposure and on maintaining personal and group hygiene. All abrasions and sores of the skin and mucous membranes should be treated with appropriate antiseptics and covered with clean dressings, and all clothing in contact with yaws lesions should be sterilized or destroyed.
Possible Complications
Yaws can be disfiguring and disabling because it may cause gross destruction of the skin and bones. It can also cause deformities of the legs, nose, palate, and upper jaw.
Prevention
Mass campaigns for eradication of yaws via penicillin treatment in the 1950s and 1960s have dramatically decreased the worldwide incidence of yaws. Contact the medical provider if you or your child have a chronic skin or bone lesion and have resided in tropical areas where yaws is known to occur.
The final stage involves destructive lesions of the skin and bones which can lead to severe disfigurement and disability. It occurs in up to 20% of untreated individuals
Yaws tends to strike children, particularly between the ages of two and five. It is common in areas where poverty and overcrowding interfere with good hygiene practices. The most common locations are in rural areas throughout Africa, Southeast Asia, and in locations bordering the equator in the Americas.
Yaws is transmitted by direct contact with skin lesions of infected people. Approximately two to four weeks after infection, the child develops a sore "mother yaw" where the organism entered the skin.
If untreated a secondary stage occurs after up to four months of latency, it is marked by more 'raspberry' growths but smaller and ulcerous - exuding a thin, highly infective fluid which attracts flies. These growths may also merge together into thick fissured plaques, which can occur on the feet and induce a distinctive gait. These secondary growths are irreversible but there can be relapsing lesions and asymptomatic periods.
The major route of infection is through direct person-to-person contact. The treponemes associated with yaws are located primarily in the epidermis. The ulcerative skin lesions that develop early in the disease course are teeming with spirochetes, which can be transmitted via direct skin-to-skin contact and via breaks in the skin due to trauma, bites, or excoriations.
Yaws, like syphilis, has been classified into the following 4 stages:
1. Primary stage: The initial yaws lesion develops at the inoculation site.
2. Secondary stage: Widespread dissemination of treponemes results in multiple skin lesions similar to the primary yaws lesion.
3. Latent stage: Symptoms are usually absent, but skin lesions can relapse.
4. Tertiary stage: Bone, joint, and soft tissue deformities may occur.
Another classification distinguishes early yaws from late yaws. Early yaws includes primary and secondary stages and is characterized by the presence of contagious skin lesions. Late yaws includes the tertiary stage, when lesions are not contagious.
In 10-20% of cases the disease can progress over a decade or more to a tertiary stage with destructive lesions of the skin and bones. Large subcutaneous nodules develop and grow before abscessing and ulcerating, these can become infected and may merge together forming serpiginous tracts. These tracts heal with keloid formation which can cause deformities, disabilities and limb contractures. The bone lesions caused are periostitis, osteitis, and osteomyelitis, damage to the tibia can lead to a condition known as sabre shins. In a very few cases a condition known as goundou is caused where growths on the nasal maxillae can result in extensive and severe damage to the nose and palate.
Symptoms
Initial, single skin lesion that may grow slowly and have a raspberry-like appearance. It may also form an ulcer and is usually painless.
• Satellite lesions which may become large nodules/growths throughout the body and may have superficial erosions in secondary yaws.
• Fever may be present in secondary yaws.
• Bone pain/bone destruction; saber shins.
• Finger inflammation (dactylitis).
The first symptom of yaws occurs three to four weeks after acquiring the bacteria. The area where the bacteria originally entered the skin becomes a noticeable bump (papule). The papule grows larger and develops a punched-out center (ulcer), covered with a yellow crust. Lymph nodes in the area may become swollen and tender. This first papule may take as long as six months to heal. Secondary soft, gummy growths then appear on the face, arms and legs, and buttocks. These soft, tumor-like masses may grow on the soles of the feet, causing the patient to walk in an odd and characteristic fashion on the sides of his or her feet (nicknamed "crab yaws"). More destructive tumors may then disrupt the bones of the face, the jaw, and the lower leg. Ulcers around the nose and on the face may be very mutilating.
The largest group afflicted by Yaws are children aged 6 to 10 years in the Caribbean Islands, Latin America, West Africa, India, Oceania or Southeast Asia. There were World Health Organization funded campaigns against yaws from 1954 to 1963 which greatly reduced the incidence of the disease, although more recently numbers have risen again.
Mortality/Morbidity
• In most patients, yaws remains limited to the skin, but early bone and joint involvement can occur. Although yaws lesions disappear spontaneously, secondary bacterial infections and scarring are common complications.
• After 5-10 years, 10% of untreated patients develop destructive lesions that involve bone, cartilage, skin, and soft tissue, similar to those seen in tertiary syphilis. In contrast to venereal syphilis, cardiovascular and neurological abnormalities almost never occur in patients with yaws.
• Examination of ancient remains has led to the suggestion that yaws has affected hominids for the last 1.5 million years. The current name is believed to be of Carib origin, "yaya" meaning sore; frambesia is a Modern Latin word inspired by the French word framboise ("raspberry").
Exams and Tests
The diagnosis can be confirmed by examining a sample from a skin lesion under a special type of microscope (darkfield examination). There is no specific blood test for yaws, but because it is closely related to the bacterium that causes syphilis, the blood tests for syphilis may be positive in yaws as well. The disease is identified from blood tests or by a lesion sample through a darkfield examination under a microscope. Treatment is by a single dose of penicillin, erythromycin or tetracycline, recurrence or relapse is uncommon.
Treatment
The mainstay of treatment is a single dose of penicillin G. Relapse is rare. The goals of pharmacotherapy are to reduce morbidity and to prevent complications. Penicillin is rapidly effective in killing the spirochete and in curing yaws except in the tertiary stage, when oxophenarsine with bismuth subsalicylate is used. Prevention centres on isolating and promptly treating cases to reduce exposure and on maintaining personal and group hygiene. All abrasions and sores of the skin and mucous membranes should be treated with appropriate antiseptics and covered with clean dressings, and all clothing in contact with yaws lesions should be sterilized or destroyed.
Possible Complications
Yaws can be disfiguring and disabling because it may cause gross destruction of the skin and bones. It can also cause deformities of the legs, nose, palate, and upper jaw.
Prevention
Mass campaigns for eradication of yaws via penicillin treatment in the 1950s and 1960s have dramatically decreased the worldwide incidence of yaws. Contact the medical provider if you or your child have a chronic skin or bone lesion and have resided in tropical areas where yaws is known to occur.
The Heart Attack
7:53 PM
The heart attack (myocardial infarction) is the death of, or damage to, part of the heart muscle because its blood supply is severely reduced or stopped. The heart blood supply stop because it has been starved of oxygen.
Severe problems linked to heart attack can include heart failure and life-threatening arrhythmias (irregular heartbeats). Heart failure is a condition in which the heart can’t pump enough blood throughout the body. Ventricular fibrillation is a serious arrhythmia that can cause death if not treated quickly.
A heart attack occurs when one or more of the coronary arteries that supply blood to the heart are completely blocked and blood to the heart muscle is cut off. The blockage is usually caused by atherosclerosis, the buildup of plaque in the artery walls, and/or by a blood clot in a coronary artery.
Acting fast at the first sign of heart attack symptoms can save your life and limit damage to your heart. Treatment is most effective when started within 1 hour of the beginning of symptoms.
Approximately six in 1,000 men in the UK aged between 30-69 years, have a heart attack each year. For women, the figure is lower, at two in 1,000. Men are three times more likely to suffer from a heart attack than women. A heart attack can cause serious complications and be potentially fatal. Half of those who die do so from cardiac arrest (when the heart stops completely) within three to four hours of the start of the attack.
THE SIMPTOM
The most common symptom of heart attack is chest pain or discomfort. Most heart attacks involve discomfort in the center of the chest that lasts for more than a few minutes or goes away and comes back. The discomfort can feel like uncomfortable pressure, squeezing, fullness, or pain. It can be mild or severe. Heart attack pain can sometimes feel like indigestion or heartburn.
A heart attack usually occurs when a blood clot blocks the flow of blood through a coronary artery-a blood vessel that feeds blood to a part of the heart muscle. Interrupted blood flow to your heart can damage or destroy a part of the heart muscle.
HOW TO PREVENT?
Many heart attacks can be prevented through a healthy lifestyle, which can reduce the risk of developing coronary artery disease. For patients who have already had a heart attack, a healthy lifestyle and carefully following doctor's orders can prevent another heart attack such as :
1. A heart healthy lifestyle includes eating right, regular exercise, maintaining healthy weight, no smoking, moderate drinking, no illegal drugs, controlling hypertension, and managing stress.
2. A healthy diet includes a variety of foods that are low in fat (especially saturated fat), low in cholesterol, and high in fiber; plenty of fruits and vegetables; and limited sodium.
Saturated fat raises cholesterol, and, in excessive amounts, it increases the amount of the proteins in blood that form blood clots. Polyunsaturated and monounsaturated fats are relatively good for the heart.
Fat should comprise no more than 30 percent of total daily calories. In 2002, new evidence suggested that a diet rich in lutein, the pigment found in dark green leafy vegetables, helps artery walls fight plaque and lessens risk of heart attack.
Cholesterol should be limited to about 300 mg per day. Many popular lipid-lowering drugs can reduce LDL-cholesterol by an average of 25–30% when combined with a low-fat, low-cholesterol diet. Soluble fiber can also help lower cholesterol. Fruits and vegetables are rich in fiber, vitamins, and minerals, and they are low calorie and nearly fat free. Vitamin C and beta-carotene, found in many fruits and vegetables, keep LDL-cholesterol from turning into a form that damages coronary arteries. Excess sodium can increase the risk of high blood pressure, and daily intake should be limited to 2,400 mg—about the amount in a teaspoon of salt.
3. Regular aerobic exercise can lower blood pressure, help control weight, and increase HDL ("good") cholesterol. Moderate intensity aerobic exercise lasting about 30 minutes four or more times per week is recommended for maximum heart health, according to the Centers for Disease Control and Prevention and the American College of Sports Medicine. Three 10-minute exercise periods are also beneficial. Aerobic exercise—activities such as walking, jogging, and cycling—uses the large muscle groups and forces the body to use oxygen more efficiently. It can also include everyday activities such as active gardening, climbing stairs, or brisk housework.
4. Maintaining a desirable body weight is also important. About one quarter of all Americans are overweight, and nearly one-tenth are obese, according to the Surgeon General's Report on Nutrition and Health. People who are 20% or more over their ideal body weight have an increased risk of developing coronary artery disease. Losing weight can help reduce total and LDL cholesterol, reduce triglycerides, and boost relative levels of HDL cholesterol.
5. Smoking has many adverse effects on the heart. It increases the heart rate, constricts major arteries, and can create irregular heartbeats. It also raises blood pressure, contributes to the development of plaque, increases the formation of blood clots, and causes blood platelets to cluster and impede blood flow. Heart damage caused by smoking can be repaired by quitting—even heavy smokers can return to heart health. Several studies have shown that ex-smokers face the same risk of heart disease as non-smokers within five to 10 years of quitting.
6. Modest consumption of alcohol can actually protect against coronary artery disease. This is believed to be because alcohol raises HDL ("good") cholesterol levels in some patients. The American Heart Association defines moderate consumption as one ounce of alcohol per day—roughly one cocktail, one 8-ounce glass of wine, or two 12-ounce glasses of beer. Excessive drinking is always bad for the heart. It usually raises blood pressure, and can poison the heart and cause abnormal heart rhythms or even heart failure. Illegal drugs, like cocaine, can seriously harm the heart and should never be used.
7. Stress management means controlling mental and physical reactions to life's irritations and challenges. Techniques for controlling stress include thinking positively, getting enough sleep, exercising, and practicing relaxation techniques.
MEDICATIONS
Doctors typically prescribe drug therapy for people who've had a heart attack or who are at high risk of having one. Medications that help the heart function more effectively or reduce heart attack risk may include:
1. Blood-thinning medications. Aspirin makes your blood less "sticky" and likely to clot. Doctors recommend a daily aspirin for most people who've had a heart attack. Your doctor may, in some cases, prescribe a stronger blood thinner than aspirin.
Daily aspirin therapy has been proven to help prevent blood clots associated with atherosclerosis. It can also prevent heart attacks from recurring, prevent heart attacks from being fatal, and lower the risk of strokes. Surprisingly, a 2002 study found that aspirin therapy is underused by people at risk for heart attacks. Patients should consult their doctors before taking aspirin regularly.
2. Beta blockers. These drugs lower your heart rate and blood pressure, reducing demand on your heart and helping to prevent further heart attacks. Many patients will need to take beta blockers for the rest of their lives following a heart attack.
3. Angiotensin-converting enzyme (ACE) inhibitors. Doctors prescribe ACE inhibitors for most patients after heart attacks, especially for those who have had a moderate to severe heart attack that has reduced the heart's pumping capacity. These drugs allow blood to flow from your heart more easily, prevent some of the complications of heart attacks, and make a second heart attack less likely.
4. Cholesterol-lowering medications. A variety of medications, including statins, niacin, fibrates and bile acid sequestrants, can help lower your levels of unwanted blood cholesterol. The majority of people who've had a heart attack take cholesterol-lowering medications — drugs that help lower the risk of a second heart attack. These medications can help prevent future heart attacks even if your cholesterol was not very high at the time of the heart attack.
Severe problems linked to heart attack can include heart failure and life-threatening arrhythmias (irregular heartbeats). Heart failure is a condition in which the heart can’t pump enough blood throughout the body. Ventricular fibrillation is a serious arrhythmia that can cause death if not treated quickly.
A heart attack occurs when one or more of the coronary arteries that supply blood to the heart are completely blocked and blood to the heart muscle is cut off. The blockage is usually caused by atherosclerosis, the buildup of plaque in the artery walls, and/or by a blood clot in a coronary artery.
Acting fast at the first sign of heart attack symptoms can save your life and limit damage to your heart. Treatment is most effective when started within 1 hour of the beginning of symptoms.
Approximately six in 1,000 men in the UK aged between 30-69 years, have a heart attack each year. For women, the figure is lower, at two in 1,000. Men are three times more likely to suffer from a heart attack than women. A heart attack can cause serious complications and be potentially fatal. Half of those who die do so from cardiac arrest (when the heart stops completely) within three to four hours of the start of the attack.
THE SIMPTOM
The most common symptom of heart attack is chest pain or discomfort. Most heart attacks involve discomfort in the center of the chest that lasts for more than a few minutes or goes away and comes back. The discomfort can feel like uncomfortable pressure, squeezing, fullness, or pain. It can be mild or severe. Heart attack pain can sometimes feel like indigestion or heartburn.
A heart attack usually occurs when a blood clot blocks the flow of blood through a coronary artery-a blood vessel that feeds blood to a part of the heart muscle. Interrupted blood flow to your heart can damage or destroy a part of the heart muscle.
HOW TO PREVENT?
Many heart attacks can be prevented through a healthy lifestyle, which can reduce the risk of developing coronary artery disease. For patients who have already had a heart attack, a healthy lifestyle and carefully following doctor's orders can prevent another heart attack such as :
1. A heart healthy lifestyle includes eating right, regular exercise, maintaining healthy weight, no smoking, moderate drinking, no illegal drugs, controlling hypertension, and managing stress.
2. A healthy diet includes a variety of foods that are low in fat (especially saturated fat), low in cholesterol, and high in fiber; plenty of fruits and vegetables; and limited sodium.
Saturated fat raises cholesterol, and, in excessive amounts, it increases the amount of the proteins in blood that form blood clots. Polyunsaturated and monounsaturated fats are relatively good for the heart.
Fat should comprise no more than 30 percent of total daily calories. In 2002, new evidence suggested that a diet rich in lutein, the pigment found in dark green leafy vegetables, helps artery walls fight plaque and lessens risk of heart attack.
Cholesterol should be limited to about 300 mg per day. Many popular lipid-lowering drugs can reduce LDL-cholesterol by an average of 25–30% when combined with a low-fat, low-cholesterol diet. Soluble fiber can also help lower cholesterol. Fruits and vegetables are rich in fiber, vitamins, and minerals, and they are low calorie and nearly fat free. Vitamin C and beta-carotene, found in many fruits and vegetables, keep LDL-cholesterol from turning into a form that damages coronary arteries. Excess sodium can increase the risk of high blood pressure, and daily intake should be limited to 2,400 mg—about the amount in a teaspoon of salt.
3. Regular aerobic exercise can lower blood pressure, help control weight, and increase HDL ("good") cholesterol. Moderate intensity aerobic exercise lasting about 30 minutes four or more times per week is recommended for maximum heart health, according to the Centers for Disease Control and Prevention and the American College of Sports Medicine. Three 10-minute exercise periods are also beneficial. Aerobic exercise—activities such as walking, jogging, and cycling—uses the large muscle groups and forces the body to use oxygen more efficiently. It can also include everyday activities such as active gardening, climbing stairs, or brisk housework.
4. Maintaining a desirable body weight is also important. About one quarter of all Americans are overweight, and nearly one-tenth are obese, according to the Surgeon General's Report on Nutrition and Health. People who are 20% or more over their ideal body weight have an increased risk of developing coronary artery disease. Losing weight can help reduce total and LDL cholesterol, reduce triglycerides, and boost relative levels of HDL cholesterol.
5. Smoking has many adverse effects on the heart. It increases the heart rate, constricts major arteries, and can create irregular heartbeats. It also raises blood pressure, contributes to the development of plaque, increases the formation of blood clots, and causes blood platelets to cluster and impede blood flow. Heart damage caused by smoking can be repaired by quitting—even heavy smokers can return to heart health. Several studies have shown that ex-smokers face the same risk of heart disease as non-smokers within five to 10 years of quitting.
6. Modest consumption of alcohol can actually protect against coronary artery disease. This is believed to be because alcohol raises HDL ("good") cholesterol levels in some patients. The American Heart Association defines moderate consumption as one ounce of alcohol per day—roughly one cocktail, one 8-ounce glass of wine, or two 12-ounce glasses of beer. Excessive drinking is always bad for the heart. It usually raises blood pressure, and can poison the heart and cause abnormal heart rhythms or even heart failure. Illegal drugs, like cocaine, can seriously harm the heart and should never be used.
7. Stress management means controlling mental and physical reactions to life's irritations and challenges. Techniques for controlling stress include thinking positively, getting enough sleep, exercising, and practicing relaxation techniques.
MEDICATIONS
Doctors typically prescribe drug therapy for people who've had a heart attack or who are at high risk of having one. Medications that help the heart function more effectively or reduce heart attack risk may include:
1. Blood-thinning medications. Aspirin makes your blood less "sticky" and likely to clot. Doctors recommend a daily aspirin for most people who've had a heart attack. Your doctor may, in some cases, prescribe a stronger blood thinner than aspirin.
Daily aspirin therapy has been proven to help prevent blood clots associated with atherosclerosis. It can also prevent heart attacks from recurring, prevent heart attacks from being fatal, and lower the risk of strokes. Surprisingly, a 2002 study found that aspirin therapy is underused by people at risk for heart attacks. Patients should consult their doctors before taking aspirin regularly.
2. Beta blockers. These drugs lower your heart rate and blood pressure, reducing demand on your heart and helping to prevent further heart attacks. Many patients will need to take beta blockers for the rest of their lives following a heart attack.
3. Angiotensin-converting enzyme (ACE) inhibitors. Doctors prescribe ACE inhibitors for most patients after heart attacks, especially for those who have had a moderate to severe heart attack that has reduced the heart's pumping capacity. These drugs allow blood to flow from your heart more easily, prevent some of the complications of heart attacks, and make a second heart attack less likely.
4. Cholesterol-lowering medications. A variety of medications, including statins, niacin, fibrates and bile acid sequestrants, can help lower your levels of unwanted blood cholesterol. The majority of people who've had a heart attack take cholesterol-lowering medications — drugs that help lower the risk of a second heart attack. These medications can help prevent future heart attacks even if your cholesterol was not very high at the time of the heart attack.
The Avian Influenza
9:23 PM
Bird flu" is an illness caused by any of many different strains of influenza viruses that have adapted to a specific host. All known viruses that cause influenza in birds belong to the species: Influenza A virus. All subtypes (but not all strains of all subtypes) of Influenza A virus are adapted to birds, which is why for many purposes avian flu virus is the Influenza A virus.
Avian (bird) flu is caused by influenza A viruses that occur naturally among birds. There are different subtypes of these viruses because of changes in certain proteins (hemagglutinin [HA] and neuraminidase [NA]) on the surface of the influenza A virus and the way the proteins combine.
In Asia, many people live with ducks and chickens in their homes and in their yards. Health and veterinary officials worldwide announced that a key way to stop the spread of the disease is to improve farming practices, segregating poultry from humans, and culling birds that have been infected with the deadly virus. Bird flu was thought only to infect birds until the first human cases were seen in Hong Kong in 1997.
The most contagious strains, which are usually fatal in birds, are H5 and H7.
There are nine different types of H5. The nine all take different forms - some are highly pathogenic, while some are pretty harmless. The type currently causing concern is the "highly pathogenic" Asian strain of the H5N1 virus.
Health professionals are concerned that the continued spread of a highly pathogenic avian H5N1 virus across eastern Asia and other countries represents a significant threat to human health. The H5N1 virus has raised concerns about a potential human pandemic because:
Symptoms are similar to other types of flu - fever, malaise, sore throats and coughs. People can also develop conjunctivitis. Researchers are now concerned because scientists studying a case in Vietnam found the virus can affect all parts of the body, not just the lungs. This could mean that many illnesses, and even deaths, thought to have been caused by something else, may have been due to the bird flu virus.
Migrating birds, like ducks, geese, and swans, can carry and spread the virus to other birds — often across country borders. Some of these migratory birds don't seem to get sick from bird flu, but domesticated birds like chickens and turkeys can die from it. The virus can also spread from farm to farm if birds' infected feces and saliva get on farming equipment, like tractor wheels, clothing, and cages. Poultry also roam freely in some of those areas, and there are lots of opportunities to be exposed to their infected feces.
It's unlikely that a person who gets infected with the H5N1 strain of the avian flu will spread it to other people. All the human cases of bird flu so far have happened because people got it directly from infected birds.
Until January 2008, the World Health Organization (WHO) had confirmed 348 cases of H5N1 in humans in Azerbaijan, Cambodia, China, Djibouti, Egypt, Indonesia, Iraq, Lao People's Democratic Republic, Myanmar, Nigeria, Pakistan, Thailand, Turkey and Vietnam, leading to 216 deaths.
There is not yet a definitive vaccine, but prototypes which offer protection against the H5N1 strain are being produced. But antiviral drugs, such as Tamiflu which are already available and being stockpiled by countries such as the UK, may help limit symptoms and reduce the chances the disease will spread. Concerns have been prompted by news that patients in Vietnam have become partially resistant to the Tamiflu, the drug that doctors plan to use to tackle a human bird flu outbreak.
Since the avian flu virus is destroyed by heat, be sure to eat only well-cooked poultry and eggs. Make sure that utensils and kitchen surfaces where eggs and raw poultry are handled are kept clean. Separate raw poultry from cooked foods. In the meantime, good hygiene remains the best prevention: keep hands well-washed, and avoid contact with people who have been infected with the virus. So, It's safe to eat properly cooked chicken, turkey, and any other poultry in the United States. Heat can destroy flu viruses, so cook poultry so that the temperature of the meat reaches at least 158° Fahrenheit (70° Celsius). Do not eat uncooked or undercooked poultry or poultry products
The conclusion is we have to fund, advice, and other support to your state to assist with pandemic planning and preparation. Information on state/federal planning and cooperation, including links to state pandemic plans, is available on this site.
Avian (bird) flu is caused by influenza A viruses that occur naturally among birds. There are different subtypes of these viruses because of changes in certain proteins (hemagglutinin [HA] and neuraminidase [NA]) on the surface of the influenza A virus and the way the proteins combine.
In Asia, many people live with ducks and chickens in their homes and in their yards. Health and veterinary officials worldwide announced that a key way to stop the spread of the disease is to improve farming practices, segregating poultry from humans, and culling birds that have been infected with the deadly virus. Bird flu was thought only to infect birds until the first human cases were seen in Hong Kong in 1997.
The most contagious strains, which are usually fatal in birds, are H5 and H7.
There are nine different types of H5. The nine all take different forms - some are highly pathogenic, while some are pretty harmless. The type currently causing concern is the "highly pathogenic" Asian strain of the H5N1 virus.
Health professionals are concerned that the continued spread of a highly pathogenic avian H5N1 virus across eastern Asia and other countries represents a significant threat to human health. The H5N1 virus has raised concerns about a potential human pandemic because:
Symptoms are similar to other types of flu - fever, malaise, sore throats and coughs. People can also develop conjunctivitis. Researchers are now concerned because scientists studying a case in Vietnam found the virus can affect all parts of the body, not just the lungs. This could mean that many illnesses, and even deaths, thought to have been caused by something else, may have been due to the bird flu virus.
Migrating birds, like ducks, geese, and swans, can carry and spread the virus to other birds — often across country borders. Some of these migratory birds don't seem to get sick from bird flu, but domesticated birds like chickens and turkeys can die from it. The virus can also spread from farm to farm if birds' infected feces and saliva get on farming equipment, like tractor wheels, clothing, and cages. Poultry also roam freely in some of those areas, and there are lots of opportunities to be exposed to their infected feces.
It's unlikely that a person who gets infected with the H5N1 strain of the avian flu will spread it to other people. All the human cases of bird flu so far have happened because people got it directly from infected birds.
Until January 2008, the World Health Organization (WHO) had confirmed 348 cases of H5N1 in humans in Azerbaijan, Cambodia, China, Djibouti, Egypt, Indonesia, Iraq, Lao People's Democratic Republic, Myanmar, Nigeria, Pakistan, Thailand, Turkey and Vietnam, leading to 216 deaths.
There is not yet a definitive vaccine, but prototypes which offer protection against the H5N1 strain are being produced. But antiviral drugs, such as Tamiflu which are already available and being stockpiled by countries such as the UK, may help limit symptoms and reduce the chances the disease will spread. Concerns have been prompted by news that patients in Vietnam have become partially resistant to the Tamiflu, the drug that doctors plan to use to tackle a human bird flu outbreak.
Since the avian flu virus is destroyed by heat, be sure to eat only well-cooked poultry and eggs. Make sure that utensils and kitchen surfaces where eggs and raw poultry are handled are kept clean. Separate raw poultry from cooked foods. In the meantime, good hygiene remains the best prevention: keep hands well-washed, and avoid contact with people who have been infected with the virus. So, It's safe to eat properly cooked chicken, turkey, and any other poultry in the United States. Heat can destroy flu viruses, so cook poultry so that the temperature of the meat reaches at least 158° Fahrenheit (70° Celsius). Do not eat uncooked or undercooked poultry or poultry products
The conclusion is we have to fund, advice, and other support to your state to assist with pandemic planning and preparation. Information on state/federal planning and cooperation, including links to state pandemic plans, is available on this site.
The Antibiotics Resistance
9:22 PM
Antibiotic resistance is the ability of a bacterium or other microorganism to survive and reproduce in the presence of antibiotic doses that were previously thought effective against them. Examples of microbe resistance to antibiotics dot the countryside, plaguing humankind. For instance, in February 1994 dozens of students at La Quinta High School in southern California were exposed to the pathogenic (disease-causing) agent, Mycobacterium tuberculosis, and eleven were diagnosed with active tuberculosis. Many strains of this bacterium are multi-drug resistant (MDR). As for the sexually transmitted pathogen Neisseria gonorrhea, which causes gonorrhea, the antibiotics penicillin and tetracycline that were used against it in the 1980s can no longer be the first lines of defense, again because of antibiotic resistance. If only 2 percent of a N. gonorrhea population is antibiotic resistant, a community-wide infection of this persistent strain can occur.
Mechanisms of Resistance
Antibiotics, whether made in the laboratory or in nature by other microbes, are designed to hinder metabolic processes such as cell wall synthesis, protein synthesis, or transcription, among others. If humans are to prosper against microbial disease, it is necessary to understand how and why bacteria are able to mount their clever defenses. Aided with the knowledge of the genetics and mechanisms of resistance, scientists can discover new ways to combat the resistant bacteria.
The phenomenon of antibiotic resistance in some cases is innate to the microbe. For instance, penicillin directly interferes with the synthesis of bacterial cell walls. Therefore, it is useless against many other microbes such as fungi, viruses, wall-less bacteria like Mycoplasma (which causes "walking pneumonia"), and even many Gram negative bacteria whose outer membrane prevents penicillin from penetrating them. Other bacteria change their "genetic programs," which allows them to circumvent the antibiotic effect. These changes in the genetic programs can be in the form of chromosomal mutations, acquisition of R (resistance) plasmids, or through transposition of "pathogenicity islands."
The third method is transfer due to transposable elements on either side of a "pathogenicity island," which is group of genes that appear on the DNA and carry the codes for several factors which make the infection more successful. These transposable elements allow the genes to jump from bacteria to bacteria or simply from chromosome to plasmid within the organism.
The "road blocks" that bacteria have evolved which result in antibiotic resistance employ several mechanisms. One strategy is simply to destroy or limit the activity of the antibiotic. The beta-lactamases are enzymes which render the penicillin-like antibiotics dysfunctional by cleaving a vital part of the molecule. Some bacteria can deactivate antibiotics by adding chemical groups to them; for instance, by changing the electrical charge of the antibiotic through the addition of a phosphate group. Other bacteria accomplish a similar effect by bulking themselves up with the addition of an acetyl group.
Still other bacteria acquire resistance by simply not allowing the antibiotic to enter the cell. The bacterium mentioned above, Neisseria gonorrhea, has altered porin proteins, thereby stopping uptake of the antibiotic. Some bacteria acquire intricate pumping mechanisms to expel the drug when it gains entry to their cell.
Finally, bacteria may mutate the gene for the target macromolecule with which the antibiotic is supposed to bind. For example, tetracycline binds to and inhibits ribosomes, so a mutation in the ribosomal genes may cause conformational alterations in the ribosomal proteins that prevent tetracycline from binding but still allow the ribosome to function.
The effects of antibiotic resistance are reflected in the agriculture, food, medical, and pharmaceutical industries. Livestock are fed about half of the antibiotics manufactured in the United States as a preventative measure, rather than in the treatment of specific diseases. Such usage has resulted in hamburger meat that contains drug-resistant and difficult-to-treat Salmonella Newport, which has led to seventeen cases of gastroenteritis including one death. Some MDR-tuberculoid strains arise because patients are reluctant to follow the six-months or more of treatment needed to effectively cure tuberculosis. If the drug regimen is not followed, less sensitive bacteria have the chance to multiply and gradually emerge into resistant strains. In other cases the "shotgun" method of indiscriminately prescribing/taking several antibiotics runs the risk of creating "super MDR-germs." Moreover, millions of antibiotic prescriptions are written by physicians each year for viral infections, against which antibiotics are useless. The patient insists on a prescription, and many doctors willingly go along with the request.
Because global travel is common, the potential of creating pandemics is looming. In many Third World countries, diluted antibiotics are sold on the black market. The dosage taken is often too low to be effective, or the patient takes the drug for a very short time. All these behaviors contribute to the development of resistant strains of infectious organisms. If humans are to gain the upper hand against MDR bacteria, it is the responsibility of these industries and the public to educate themselves and to engage in careful practices and therapy.
Mechanisms of Resistance
Antibiotics, whether made in the laboratory or in nature by other microbes, are designed to hinder metabolic processes such as cell wall synthesis, protein synthesis, or transcription, among others. If humans are to prosper against microbial disease, it is necessary to understand how and why bacteria are able to mount their clever defenses. Aided with the knowledge of the genetics and mechanisms of resistance, scientists can discover new ways to combat the resistant bacteria.
The phenomenon of antibiotic resistance in some cases is innate to the microbe. For instance, penicillin directly interferes with the synthesis of bacterial cell walls. Therefore, it is useless against many other microbes such as fungi, viruses, wall-less bacteria like Mycoplasma (which causes "walking pneumonia"), and even many Gram negative bacteria whose outer membrane prevents penicillin from penetrating them. Other bacteria change their "genetic programs," which allows them to circumvent the antibiotic effect. These changes in the genetic programs can be in the form of chromosomal mutations, acquisition of R (resistance) plasmids, or through transposition of "pathogenicity islands."
The third method is transfer due to transposable elements on either side of a "pathogenicity island," which is group of genes that appear on the DNA and carry the codes for several factors which make the infection more successful. These transposable elements allow the genes to jump from bacteria to bacteria or simply from chromosome to plasmid within the organism.
The "road blocks" that bacteria have evolved which result in antibiotic resistance employ several mechanisms. One strategy is simply to destroy or limit the activity of the antibiotic. The beta-lactamases are enzymes which render the penicillin-like antibiotics dysfunctional by cleaving a vital part of the molecule. Some bacteria can deactivate antibiotics by adding chemical groups to them; for instance, by changing the electrical charge of the antibiotic through the addition of a phosphate group. Other bacteria accomplish a similar effect by bulking themselves up with the addition of an acetyl group.
Still other bacteria acquire resistance by simply not allowing the antibiotic to enter the cell. The bacterium mentioned above, Neisseria gonorrhea, has altered porin proteins, thereby stopping uptake of the antibiotic. Some bacteria acquire intricate pumping mechanisms to expel the drug when it gains entry to their cell.
Finally, bacteria may mutate the gene for the target macromolecule with which the antibiotic is supposed to bind. For example, tetracycline binds to and inhibits ribosomes, so a mutation in the ribosomal genes may cause conformational alterations in the ribosomal proteins that prevent tetracycline from binding but still allow the ribosome to function.
The effects of antibiotic resistance are reflected in the agriculture, food, medical, and pharmaceutical industries. Livestock are fed about half of the antibiotics manufactured in the United States as a preventative measure, rather than in the treatment of specific diseases. Such usage has resulted in hamburger meat that contains drug-resistant and difficult-to-treat Salmonella Newport, which has led to seventeen cases of gastroenteritis including one death. Some MDR-tuberculoid strains arise because patients are reluctant to follow the six-months or more of treatment needed to effectively cure tuberculosis. If the drug regimen is not followed, less sensitive bacteria have the chance to multiply and gradually emerge into resistant strains. In other cases the "shotgun" method of indiscriminately prescribing/taking several antibiotics runs the risk of creating "super MDR-germs." Moreover, millions of antibiotic prescriptions are written by physicians each year for viral infections, against which antibiotics are useless. The patient insists on a prescription, and many doctors willingly go along with the request.
Because global travel is common, the potential of creating pandemics is looming. In many Third World countries, diluted antibiotics are sold on the black market. The dosage taken is often too low to be effective, or the patient takes the drug for a very short time. All these behaviors contribute to the development of resistant strains of infectious organisms. If humans are to gain the upper hand against MDR bacteria, it is the responsibility of these industries and the public to educate themselves and to engage in careful practices and therapy.
The Antibiotics
9:21 PM
Antibiotics may be informally defined as the sub-group of anti-infectives that are derived from bacterial sources and are used to treat bacterial infections. Other classes of drugs, most notably the sulfonamides, may be effective antibacterials. Similarly, some antibiotics may have secondary uses, such as the use of demeclocycline (Declomycin, a tetracycline derivative) to treat the syndrome of inappropriate antidiuretic hormone (SIADH) secretion. Other antibiotics may be useful in treating protozoal infections.
Description
Classifications
Although there are several classification schemes for antibiotics, based on bacterial spectrum (broad versus narrow) or route of administration (injectable versus oral versus topical), or type of activity (bactericidal vs. bacteriostatic), the most useful is based on chemical structure. Antibiotics within a structural class will generally show similar patterns of effectiveness, toxicity, and allergic potential.
1. PENICILLINS. The penicillins are the oldest class of antibiotics, and have a common chemical structure which they share with the cephalopsorins. The two groups are classed as the beta-lactam antibiotics, and are generally bacteriocidal—that is, they kill bacteria rather than inhibiting growth. The penicillins can be further subdivided. The natural pencillins are based on the original penicillin G structure; penicillinase-resistant penicillins, notably methicillin and oxacillin, are active even in the presence of the bacterial enzyme that inactivates most natural penicillins. Aminopenicillins such as ampicillin and amoxicillin have an extended spectrum of action compared with the natural penicillins; extended spectrum penicillins are effective against a wider range of bacteria. These generally include coverage for Pseudomonas aeruginaosa and may provide the penicillin in combination with a penicillinase inhibitor.
2. CEPHALOSPORINS. Cephalosporins and the closely related cephamycins and carbapenems, like the pencillins, contain a beta-lactam chemical structure. Consequently, there are patterns of cross-resistance and cross-allergenicity among the drugs in these classes. The "cepha" drugs are among the most diverse classes of antibiotics, and are themselves subgrouped into 1st, 2nd and 3rd generations. Each generation has a broader spectrum of activity than the one before. In addition, cefoxitin, a cephamycin, is highly active against anaerobic bacteria, which offers utility in treatment of abdominal infections. The 3rd generation drugs, cefotaxime, ceftizoxime, ceftriaxone and others, cross the blood-brain barrier and may be used to treat meningitis and encephalitis. Cephalopsorins are the usually preferred agents for surgical prophylaxis.
3. FLUROQUINOLONES. The fluroquinolones are synthetic antibacterial agents, and not derived from bacteria. They are included here because they can be readily interchanged with traditional antibiotics. An earlier, related class of antibacterial agents, the quinolones, were not well absorbed, and could be used only to treat urinary tract infections. The fluroquinolones, which are based on the older group, are broad-spectrum bacteriocidal drugs that are chemically unrelated to the penicillins or the cephaloprosins. They are well distributed into bone tissue, and so well absorbed that in general they are as effective by the oral route as by intravenous infusion.
4. TETRACYCLINES. Tetracyclines got their name because they share a chemical structure that has four rings. They are derived from a species of Streptomyces bacteria. Broad-spectrum bacteriostatic agents, the tetracyclines may be effective against a wide variety of microorganisms, including rickettsia and amebic parasites.
5. MACROLIDES. The macrolide antibiotics are derived from Streptomyces bacteria, and got their name because they all have a macrocyclic lactone chemical structure. Erythromycin, the prototype of this class, has a spectrum and use similar to penicillin. Newer members of the group, azithromycin and clarithyromycin, are particularly useful for their high level of lung penetration. Clarithromycin has been widely used to treat Helicobacter pylori infections, the cause of stomach ulcers.
6. OTHERS. Other classes of antibiotics include the aminoglycosides, which are particularly useful for their effectiveness in treating Pseudomonas aeruginosa infections; the lincosamindes, clindamycin and lincomycin, which are highly active against anaerobic pathogens. There are other, individual drugs which may have utility in specific infections.
Description
Classifications
Although there are several classification schemes for antibiotics, based on bacterial spectrum (broad versus narrow) or route of administration (injectable versus oral versus topical), or type of activity (bactericidal vs. bacteriostatic), the most useful is based on chemical structure. Antibiotics within a structural class will generally show similar patterns of effectiveness, toxicity, and allergic potential.
1. PENICILLINS. The penicillins are the oldest class of antibiotics, and have a common chemical structure which they share with the cephalopsorins. The two groups are classed as the beta-lactam antibiotics, and are generally bacteriocidal—that is, they kill bacteria rather than inhibiting growth. The penicillins can be further subdivided. The natural pencillins are based on the original penicillin G structure; penicillinase-resistant penicillins, notably methicillin and oxacillin, are active even in the presence of the bacterial enzyme that inactivates most natural penicillins. Aminopenicillins such as ampicillin and amoxicillin have an extended spectrum of action compared with the natural penicillins; extended spectrum penicillins are effective against a wider range of bacteria. These generally include coverage for Pseudomonas aeruginaosa and may provide the penicillin in combination with a penicillinase inhibitor.
2. CEPHALOSPORINS. Cephalosporins and the closely related cephamycins and carbapenems, like the pencillins, contain a beta-lactam chemical structure. Consequently, there are patterns of cross-resistance and cross-allergenicity among the drugs in these classes. The "cepha" drugs are among the most diverse classes of antibiotics, and are themselves subgrouped into 1st, 2nd and 3rd generations. Each generation has a broader spectrum of activity than the one before. In addition, cefoxitin, a cephamycin, is highly active against anaerobic bacteria, which offers utility in treatment of abdominal infections. The 3rd generation drugs, cefotaxime, ceftizoxime, ceftriaxone and others, cross the blood-brain barrier and may be used to treat meningitis and encephalitis. Cephalopsorins are the usually preferred agents for surgical prophylaxis.
3. FLUROQUINOLONES. The fluroquinolones are synthetic antibacterial agents, and not derived from bacteria. They are included here because they can be readily interchanged with traditional antibiotics. An earlier, related class of antibacterial agents, the quinolones, were not well absorbed, and could be used only to treat urinary tract infections. The fluroquinolones, which are based on the older group, are broad-spectrum bacteriocidal drugs that are chemically unrelated to the penicillins or the cephaloprosins. They are well distributed into bone tissue, and so well absorbed that in general they are as effective by the oral route as by intravenous infusion.
4. TETRACYCLINES. Tetracyclines got their name because they share a chemical structure that has four rings. They are derived from a species of Streptomyces bacteria. Broad-spectrum bacteriostatic agents, the tetracyclines may be effective against a wide variety of microorganisms, including rickettsia and amebic parasites.
5. MACROLIDES. The macrolide antibiotics are derived from Streptomyces bacteria, and got their name because they all have a macrocyclic lactone chemical structure. Erythromycin, the prototype of this class, has a spectrum and use similar to penicillin. Newer members of the group, azithromycin and clarithyromycin, are particularly useful for their high level of lung penetration. Clarithromycin has been widely used to treat Helicobacter pylori infections, the cause of stomach ulcers.
6. OTHERS. Other classes of antibiotics include the aminoglycosides, which are particularly useful for their effectiveness in treating Pseudomonas aeruginosa infections; the lincosamindes, clindamycin and lincomycin, which are highly active against anaerobic pathogens. There are other, individual drugs which may have utility in specific infections.
RSS Feed (xml)