Shirin S's List: Tuberculosis

• Robert Koch, a German physician and scientist,  presented his discovery of Mycobacterium  tuberculosis, the bacterium that causes  tuberculosis (TB), on the evening of March 24, 1882.
• Robert Koch was  now a famous scientist and became known as "The  Father of Bacteriology." He was presented with the  Nobel Prize in Physiology or Medicine in 1905 "for  his investigations and discoveries in relation to  tuberculosis."
• Tuberculosis is a global disease which is not only  specific to humans. There are variants of the TB  bacterium that infect cattle (milk was known to  transmit the disease from cattle to humans before  heat treatment - pasteurization - efficiently removed  the risk), birds, fish, turtles and frogs.
• After Koch's discovery, many attempts were made  over the years to find a compound that could stop the  growth of TB bacteria. In 1910, a German scientist  named Paul Ehrlich discovered a chemical that could  kill the microorganism that causes another disease,  syphilis, and effectively treat that disease. This  initiated the search for other chemical substances  which could destroy disease-causing  microorganisms.
• In 1935, another German scientist named Gerhard  Domagk published a report on the use of "Prontosil,"  an organic compound containing sulfur  (sulfanilamide), for treatment of bacterial  infections. Domagk was awarded The Nobel Prize in  Physiology or Medicine for his discovery in 1939.  Prontosil, and derivatives of it, had some effect on  TB bacteria in laboratory studies, but only in  concentrations that would be poisonous to humans.

• Another drug called "isoniazid," a derivative of a  compound researched earlier by Domagk, was developed  in 1952. It also found its place in TB therapy.

    

  Thus, in the decade between 1944 and 1954, largely  due to the work of Nobel Laureates, three drugs -  streptomycin, PAS and isoniazid – became  available. When taken in combination, and for a  sufficient length of time, the prognosis for a  patient with TB disease changed from dismal to the  expectation of cure.
• Tuberculosis, once called "consumption" and "white  plague," is an ancient disease that may have always  been with us. Evidence of tubercular decay found in  the skulls and spines of Egyptian mummies, tell us  that TB has been plaguing humans for at least 4,000  years. Hippocrates, the ancient Greek physician,  noted that "phthisis" (consumption) was the most  widespread and fatal disease of his time.
• It has been estimated that in the two centuries  from 1700 to 1900, tuberculosis was responsible for  the deaths of approximately one billion (one thousand  million) human beings. The annual death rate from TB  when Koch made his discovery, was seven million  people. Although the disease has not been eradicated,  there is no doubt that Robert Koch's discovery of the  tubercle bacillus, subsequent inventions for curing  infected and sick individuals as well as the  application of measures to prevent the spread of TB,  has had a profound impact on human history and has  saved many lives.

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• Over 1.5 million new TB cases per year occur in sub-Saharan Africa, nearly three million in South-East Asia and over a quarter of a million in Eastern Europe.
• It is estimated that between 2000 and 2020, nearly one billion people will be newly infected, 200 million will get sick, and 35 million will die from TB – if control measures are not significantly improved.

• The Vaccine

   
   
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    BCG (Bacillus Calmette-Guérin) is a live vaccine made  from a bacterium similar to the one that causes TB.

     
   
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    The vaccine, an injection under the skin, is usually only  given once.

     
   
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    Routine use in schoolchildren at about 12-13 years old was  in place from 1953-2005

     
   
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    In children over five years old it is usually only given  after a skin test.

     
   
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    It is given to those new born babies living in areas where  TB is common

     
   
   
   
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    It is also given to children of all ages who are considered  to be at high risk of catching TB  

     
   
   
   
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    Frequently it will leave a small scar but other side effects  are rare.

     
   
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    When given to school children it protects about 70-80% of them.

     
   
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    Protection is best against the more severe forms of TB.

     
   
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    Protection is probably not as good when given to babies.

     
   
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    It is not clear how long protection lasts.

• • One third of the world’s population are infected with TB.
   
  • Each year, nearly 9 million people around the world become sick with TB.
   
  • Each year, there are almost 2 million TB-related deaths worldwide.
   
  • TB is the leading killer of people who are HIV infected.
   

• Left untreated, each person with active TB disease will infect on average between 10 and 15 people every year.
• 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.

• 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 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.
• 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.
• In 2006, WHO launched the new Stop TB Strategy. The core of this strategy is DOTS, the TB control approach launched by WHO in 1995. Since its launch, more than 22 million patients have been treated under DOTS-based services. The new six-point strategy builds on this success, while recognizing the key challenges of TB/HIV and MDR-TB. It also responds to access, equity and quality constraints, and adopts evidence-based innovations in engaging with private health-care providers, empowering affected people and communities and helping to strengthen health systems and promote research.

  • 1. Pursuing high-quality DOTS expansiona and enhancement.
    2. Adressing TB/HIV, MDR-TB and other challenges.
    3. Contributing to helath system stregthening.
    4. Engaging all care providers.
    5. Empowering people with TB, and communities.
    6. Enabling and promoting research.

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• Tuberculosis (often called TB) is an infectious disease that usually attacks the lungs, but can attack almost any part of the body.
• Usually a person has to be close to someone with TB disease for a long period of time. TB is usually spread between family members, close friends, and people who work or live together. TB is spread most easily in closed spaces over a long period of time. However, transmission in an airplane, although rare, has been documented.
• Someone in the world is newly infected with TB bacilli every second and one-third of the world’s population is currently infected with TB.¹   Only about 10 percent of these people will develop TB disease in their lifetime. The other 90 percent will never get sick from the TB germs or be able to spread them to other people.²
• TB is an increasing and major world wide problem, especially in Africa where the spread has been facilitated by AIDS. It is estimated that nearly 1 billion people will become newly infected, over 150 million will become sick, and 36 million will die worldwide between now and 2020 – if control is not strengthened further. Each year there are more than 8.8 million cases and close to 1.6 million deaths attributed to TB.³

• Anyone can get TB. However, some groups are at higher risk to get active TB disease. The groups that are at high risk include:

    
   
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    People with HIV infection (the AIDS virus)
     
    
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    People in close contact with those known to be infectious with TB
     
    
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    People with medical conditions that make the body less able to protect itself from disease (for example: diabetes, the dust disease silicosis, or people undergoing treatment with drugs that can suppress the immune system, such as long-term use of corticosteroids)
     
    
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    Foreign-born people from countries with high TB rates
     
    
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    People who work in or are residents of long-term care facilities (nursing homes, prisons, some hospitals)
     
    
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    Health care workers and others such as prison guards
     
    
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    People who are malnourished
     
    
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    Alcoholics, IV drug users and people who are homeless
• Mantoux test.⁴
   
   For this test, a small amount of testing material is placed just below the top layers of skin, usually on the arm. Two to three days later a health care worker checks the arm to see if a bump has developed and measures the size of the bump. The significance of the size of the bump is determined in conjunction with risk factors for TB.
   
   Once the doctor knows that a person has TB infection he or she will want to determine if the person has TB disease. This is done by using several other tests including a chest X-ray and a test of a person's mucus (the material that is sometimes coughed up from the lungs).
• A person who has become infected with TB, but does not have active TB disease, may be given preventive therapy. Preventive therapy aims to kill germs that are not doing any damage right now, but could so do.
• the usual prescription is a daily dose of isoniazid (also called "INH"); an inexpensive TB medicine. The person takes INH for nine months (up to a year for some patients), with periodic checkups to make sure the medicine is being taken as prescribed.
• Years ago a patient with TB disease was placed in a special hospital for months, maybe even years, and would often have surgery. Today, TB can be treated with very effective drugs.
• The patient usually gets a combination of several drugs (most frequently INH plus two to three others including rifampin, pyrazinamide and ethambutol). The patient will probably begin to feel better only a few weeks after starting to take the drugs.
• If the medicine is taken incorrectly and the patient becomes sick with TB a second time, the TB may be harder to treat because it has become drug resistant. This means that the TB germs in the body are unaffected by some drugs used to treat TB.

• Multi-drug resistant tuberculosis (called MDR-TB for short) is a very dangerous form of tuberculosis. Some TB germs become resistant to the effects of some TB drugs. This happens when TB disease is not properly treated.

    

  These resistant germs can then cause TB disease. The TB disease they cause is much harder to treat because the drugs do not kill the germs. MDR-TB can be spread to others, just like regular TB.
• Extensively-drug resistant tuberculosis (XDR TB) is a strain of TB with extensive resistance to second-line drugs. XDR TB has emerged worldwide as a threat to public health and TB control, raising concerns of a future epidemic of virtually untreatable TB. Presently, XDR TB is rare in the U.S. and uncommon in the rest of the world. During 1993-2002, patients with XDR TB were 64% more likely to die or have treatment failure.⁶

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