Tuberculosis (TB) is a contagious infectious disease caused principally by the bacillus Mycobacterium tuberculosis. Transmission occurs when airborne droplets of TB germs, which are known as bacilli, are propelled into the air by a patient with pulmonary TB (TB of the lung). Infectious people can propel these droplets by talking, sneezing, spitting and most notably coughing. One cough from a pulmonary TB patient produces up to 3000 droplets. Only people who have active pulmonary TB can transmit the bacilli, though, in fact, only about half of these people are contagious.
A person infected with TB may not show symptoms since the bacilli can remain inactive for several years. The asymptomatic form is TB infection; active TB disease can develop any time after infection. Between 5-10% of those infected with TB can expect to develop active TB at some point in their lives. This percentage changes, however, with other factors contributing to a weakened immune system.
TB usually affects the lungs, but most tissues and organs can become implicated, including the bones and the brain. Patients with active TB experience fever, night sweats, fatigue, weight loss, coughing and blood-streaked sputum (phlegm), among other symptoms. Left untreated, that person will infect, on average, between 10 and 15 people per year.
Risk of infection is greatest for those with high levels of exposure to the bacillus and those with weakened immune systems. For example, prisoners in overcrowded and poorly ventilated conditions contract TB at alarming rates. For those who are affected by malnutrition, chronic illness, or HIV infection, the risk of progressing to active TB from TB infection skyrockets.
Effective treatment for TB is available, involving lengthy multiple-drug regimens. Proper treatment is difficult to obtain in developing countries, where it is needed most.
WHAT IS MULTI-DRUG RESISTANT TB?
Multi-drug resistant TB (MDR-TB) is any strain of TB that is resistant to at least the two most powerful anti-TB drugs - isoniazid and rifampicin. What's more, these strains are spread just as easily as regular TB. MDR-TB is able to thrive in the presence of drugs that would kill a regular TB bacillus. Such strains can be found all over the world.
MDR-TB evolves chiefly by inconsistent or partial treatment - when a patient does not take all their drugs regularly for the full course of treatment. People often stop taking their medications when they begin to feel better. This erratic exposure to treatment incompletely kills the bacillus and gives them time to develop mutations that can resist first-line drug treatment. Incomplete treatment can also arise from inappropriate prescribing and/or unreliable drug availability. MDR-TB is rising at an alarming rate in some countries, especially the countries of Eastern Europe, and is threatening global TB control efforts.
From the perspective of public health, poorly supervised or incomplete treatment of TB is worse than no treatment at all. People infected with TB that is resistant to first-line TB drugs will confer this resistant form of TB to people they infect. MDR-TB is treatable, but it requires treatment for up Copyright MSF to 2 years, more careful monitoring and management of treatment, and involves drugs that have a greater risk of toxicity. In addition, treatment for MDR-TB is usually too expensive for the majority—up to 250 times more expensive than treatment of non-resistant TB.
Populations at risk must be educated about TB, MDR-TB, effective treatment, and strategies for preventing transmission. Action to halt the spread of MDR-TB should address existing poor TB treatment practices. In addition, there must be increased access to treatment for MDR-TB. This is one of the aims of the Doctors Without Borders/Médecins Sans Frontières (MSF) Campaign for Access to Essential Medicines.
WHAT IS DOTS TREATMENT?
See also, DOTS: TB Cure For All?, an MSF Press Release for World TB Day 2001
Directly Observed Treatment Short-course programs (DOTS) can be an effective way to ensure completion of regular TB treatment since health care workers physically watch patients take their medications. DOTS combines five elements: political commitment, microscopy services, drug supplies, surveillance and monitoring systems and use of highly efficacious regimes with direct observation of treatment
DOTS can prevent new infections by curing infectious patients. DOTS can get people back to work, back to school, and back to their families, helping economies and improving lives. DOTS can considerably lower the indirect costs of TB.
When DOTS treatment is provided free of cost, household assets may not be sold, loans and reductions in food may be greatly reduced, and the impact on children's education can be minimized. The advantage of the DOTS strategy is a higher probability of treatment success and reduced probability of relapse.
Copyright Serge Sibert/MSF
Even with DOTS and despite adequate delivery of services, some patients with TB do not complete treatment to cure. The DOTS strategy requires adaptation in specific social, cultural and political environments. Such adaptations require guidance and technical support from global health institutions. For a successful TB control program, political commitment by policy makers and governments is crucial. Resource poor countries need compatible policies, strategies, and sufficient resources. There needs to be a thorough assessment of the successes and failures of DOTS. Transparency in achievements thus far will help to define future action. TB should not be rising despite success stories.
HOW DOES HIV/AIDS AFFECT TB?
HIV (Human Immunodeficiency Virus), the virus that causes AIDS (Acquired Immunodeficiency Syndrome) weakens a person's immune system and thus can speed the progression of TB infection to active TB. In fact, an HIV-positive person is 30 times more likely to develop TB disease from TB infection than someone who is HIV-negative.
TB is the most common infection among people with HIV. Three quarters of dually infected people live in Sub-Saharan Africa. In Africa, HIV is the single most important factor determining the increased incidence of TB in the last ten years. One-third of all AIDS-related deaths are due to TB infection, making TB the single largest killer of HIV patients.
Effective TB treatment in HIV cases can reduce the likelihood of TB infection escalating to active TB, and can extend life expectancy and quality. Treatment of TB in HIV-positive patients is, however, more complex than in other TB patients. This is because some of the drugs commonly used for TB interact adversely with HIV medications, or cause more side effects than in non-HIV patients.
WHAT IS MSF DOING TO HELP?
Doctors Without Borders/Médecins Sans Frontières (MSF) teams are working in TB programs in Africa, Asia, and the countries of the former Soviet Union. In all of these programs MSF is helping to implement DOTS. These efforts are in addition to MSF's Access to Essential Medicines Campaign, which calls for renewed research and development for an effective TB vaccine that is simple and inexpensive to implement in developing countries. MSF, along with other organizations, is working to increase access to second-line treatments for MDR-TB patients, and is negotiating with drug companies to gain a stock and sustainable production of anti-TB drugs. Finally, MSF is a partner in the Stop TB Initiative, launched in 1998 by the World Health Organization.
Copyright Serge Sibert/MSF
WHAT IS THE PURPOSE OF WORLD TB DAY?
The purpose of World TB Day is to raise awareness of the worldwide devastation caused by TB. Although the greatest burden rests on developing countries, developed Western countries are not immune to TB. With increased international travel and migration, a disease like TB can easily permeate state and regional borders. The spread of TB can, however, be stopped. Effective treatment of existing TB cases is our most immediately effective tool to prevent the spread of TB. This is why we need widespread access to good TB treatment. Vaccines exist, as do facilities to research and develop more potent vaccines to prevent TB. Vaccine development is, however, a long-term hope that will not bear fruit for many years, even if it is highly successful. At present, the will to eradicate TB is missing.
The theme for World TB Day 2001, DOTS: TB Cure For All, calls for equal access to TB care for anyone who has TB, free from discrimination - rich or poor, man or woman, adult or child, imprisoned or free, including other vulnerable groups such as people with HIV or drug resistant TB. DOTS: TB Cure For All contributes to the fulfillment of everyone's right to the enjoyment of the highest attainable standard of health.
There is more to TB control than direct observation of treatment. This warrants global leadership to assure quality of currently used drugs, promote research and development for improved treatment options, and intervention strategies. Such a ravaging disease needs utmost attention by policymakers and all implementing partners. TB is a challenge for all, and the fight is the responsibility of all.
MSF strongly supports the Global Alliance for TB Drug Development in its mandate to foster public-private partnerships aimed at finding and developing new TB treatments. However, it is imperative that governments, international agencies and the pharmaceutical industry all step up their efforts simultaneously to bring new, simpler drugs on the market to combat TB.
Become a part of the will needed to combat TB. Learn more about TB from the websites listed below. Find out how people just like you are being affected. Imagine being sick with TB but being unable to afford the medicines, and imagine that this is a reality for millions of people.
For more information on TB and the MSF Access to Essential Medicines Campaign, see the following websites: