According to recent WHO estimates, malaria causes over 1 million deaths a year. In 1998, AIDS deaths totalled some 2.5 million. Both diseases are among the five top killers worldwide. However, it is important not to overlook the dynamics in this picture. Already in 1954, millions of people were dying annually of malaria. AIDS is a still-emerging epidemic whose death toll rises every year, while the ranks of the newly infected swell by some 16 000 a day.
Tuberculosis, the second biggest infectious killer, is also on the rise, driven in large part by the HIV epidemic. People whose immune defences are weakened by HIV infection become an easy prey for other microbes, including the bacillus that causes tuberculosis. The resulting infections (along with some cancers) are responsible for the recurring illnesses which in their late stages are called “AIDS”, and which ultimately lead to death. Around 30% of all AIDS deaths result directly from tuberculosis.
While people undermined by HIV infection are more easily infected with the TB bacillus, many already harbour it from childhood. In either case, individuals with dual HIV/TB infection run a far greater risk than TB carriers who are HIV-negative that their tuberculosis will become active and potentially lethal. Worldwide, millions of people are already infected with both HIV and the tuberculosis bacillus, and the potential for further growth of co-infection in the developing countries is vast, given the crushing prevalence of TB carriers in the general population (some 30%) and the almost 6 million new HIV infections a year. Tackling the dual epidemics calls for stronger TB casefinding and treatment–tuberculosis can be cured with antibiotics regardless of whether the person is HIV-infected or not–in parallel with stronger AIDS prevention programmes to avert new HIV infections.