TB is difficult to treat. There is no single antibiotic that is capable of killing all the tubercle bacilli in a person's body. Apart from being hardy, TB germs can also develop resistance to drugs used against it. The only effective method is to use several different drugs combined together over a long period of time - usually a minimum of six months.

This presents the further difficulty of ensuring that patients actually take all of their medicines over that long period of time. After a few weeks they will usually start to feel better - the fevers and haemoptysis may recede, and they begin to gain weight.

The danger is that they will then cease taking the medications. If that happens, the patients will eventually relapse and, what is even more serious, the tubercle bacilli that have been thus exposed to a sub-lethal dose of drugs have the opportunity to develop resistance to those drugs. Once the patients start coughing again they will spread these resistant organisms to others.

MSF had good results treating TB in the Indochinese refugee camps in Thailand during the 1980s. The strategy we used there was to train community health workers from among the refugees to supervise the therapy of the TB patients on a day-to-day basis. This experience and others elsewhere were the forerunners of a strategy known as DOTS - which stands for Directly Observed Treatment, Short-course. This strategy is discussed in the section on managing the epidemic.

MSF has TB control projects in countries as diverse as Angola, Guinea, Russia, Kazakhstan and Cambodia. The drugs that we commonly use in these programmes include isoniazid, streptomycin, ethambutol, pyrazinamide and rifampicin. These medicines are usually referred to by their abbreviations: INH, SM, ETH, PZA and RIF. The commonest regimen used under DOTS is two months of daily doses of INH, RIF, PZA and EMB followed by four months of twice weekly INH and RIF. This regimen is expensive but is usually highly effective.