It’s World TB Day

Posted on March 24, 2011

Apparently, I haven’t been doing justice by my regular readers because recently my mom (a regular reader) asked me if tuberculosis is curable…

YES!!  Tuberculosis is curable!

Today (March 24th) is World TB Day, so what better day to post about the scourge of my dissertation?

Tuberculosis is caused by a bacterium called Mycobacterium tuberculosis and some of its relatives (like M. africanus and M. bovis), which make up the Mycobaterium tuberculosis complex.  It primarily affects the lungs and is spread through the air when people with the disease cough, or even talk, laugh or sing.  But it doesn’t have to affect the lungs, it could affect any part of the body.  The symptoms that often accompany TB  include weakness, night sweats, fever, loss of appetite and weight loss.

If TB is curable, why is it such a big deal?

Because the treatment for tuberculosis involves taking combination of antibiotics (multiple pills) every day for at least 6 months.  That’s a long time!  Mycobacteria are very, very slow-growing, and the antibiotics are only effective when the bacterial cells are dividing.

If an antibiotic regimen is not strictly adhered to (i.e. you stop taking your antibiotics when you feel better, or you don’t remember to take your pills every day) you aren’t going to kill off all the bacteria in your body.  A small population of resistors will remain, and these resistors are the parents of the next generation of bacteria that will attack.  What doesn’t kill them makes them stronger!

When tuberculosis becomes resistant to the first line of drugs used to treat it (multi-drug-resistant-TB or MDR-TB), patients need to be given a second line of drugs which have more unpleasant side effects, a longer treatment duration, and cost more.  When tuberculosis becomes resistant to second line drugs as well (extremely-drug-resistant-TB or XDR-TB) there’s not much that can be done.

One third of the world’s population is latently infected with TB (this means they have the bacteria in their body, they are ‘colonized’, but they are not sick).  About 10% of these people will go on to develop active TB disease.  They are more likely to develop active disease if they are immunocompromised, for example, people with AIDS or other co-infections, or people who are malnourished.  TB is a disease of poverty: it thrives in places where people have little to eat, where they suffer from multiple infections, and where they live in crowded conditions.

Because the treatment for TB takes a very long time, and can have unpleasant side effects, it makes it difficult for patients to stick with the treatment plan.

While in many countries (including Paraguay) treatment for TB is now free, in some countries patients buy as many pills as they can afford, which is not enough to complete 6 months of treatment.  There are also hidden costs to treatment, like the bus fare to travel to the health clinic everyday where your free pills are given to you in a DOTS program (where a healthcare worker observes you taking your pills every day, to make sure you complete treatment), or the time you have to take off of work to travel to the health clinic and lost wages.  In some countries, the health system is not strong enough to maintain a reliable supply of TB drugs.  TB attacks the communities that don’t have the resources to fight back.

In some places, TB patients are stigmatized.  People don’t want to be seen going to the health clinic everyday, because their neighbours will suspect they have TB and shun them.  Women with TB are abandoned by their husbands and turned out from their homes.

So TB is a big deal for many reasons: the rise of antibiotic resistant strains, the number of people affected, its attack on vulnerable populations (the poor, AIDS patients), and the barriers to treating the disease.  The best preventive measure for TB is finding new cases early and getting them through their treatment program so they are no longer infectious.  And I would add, fighting against poverty and improving the living conditions of vulnerable populations are also important if we are ever going to eradicate TB.

Some recommended reading for World TB Day:

CDC page on TB

WHO page on TB

Preventing tuberculosis deaths in India : The New Yorker.

Posted in: Tuberculosis