Cases of TB have tripled in African countries with a high HIV prevalence since 1990, according to a report released by the World Health Organisation (WHO) to mark World TB Day on March 24th. Across the world, however, TB prevalence fell by 20% in the same period and the incidence of new cases is falling or stable in all world regions with the exception of Africa.
A large number of TB cases diagnosed around the world in 2003 involved HIV-positive individuals, according to WHO. Of the calculated 4 million new active and infectious TB cases in 2003, 674,000 were in HIV-positive individuals. TB is by far the commonest AIDS-defining infection seen in resource limited settings and along with PCP pnuemonia, the commonest AIDS-defining illness in the UK.
TB prevalence increased by between 3 – 4% in African countries with a high HIV prevalence. In Uganda, which is often highlighted as an African HIV “success story” fewer patients are being cured of HIV than four years ago, and over 50% of TB patients do not receive the recommended WHO directly observed therapy short course (DOTS) TB treatment because of overwhelming pressure on the country’s health services.
Echoing former South African President, Nelson Mandela, Dr Lee Jong-Wook, director general of WHO emphasised the link between TB and HIV , saying “we can’t fight AIDS unless we do more to fight TB, and it’s time to match his words with urgent action in Africa on the two epidemics together.”
India and China, two countries which are facing growing HIV epidemics, accounted for 63% of all cases of smear-positive TB. However, WHO highlight the progress both countries are making in detecting and treating TB.
Concern was also expressed by WHO about rates of multi-drug resistant TB in Europe and slow progress in countries from the former USSR in implementing DOTS. Nevertheless WHO is confident that global incidence of TB can be reduced by 50% by 2005.
Since 1995, DOTS has provided effective TB treatment to over 17 million people worldwide, but an annual $1 billion shortfall in funding for TB controlling exists.
Despite these concerns, the UK Secretary for International Development, Hilary Benn MP, remained upbeat. “It is a remarkable achievement that we are on target to reach the goal of halving TB cases by 2015 in most places.” He nevertheless remained realistic emphasising “the destructive link between TB and AIDS in Africa is causing an increase in cases. I call on the international community to step up efforts to tackle both of these diseases together.”
Medicine Sans Frontier (MSF), the international medical aid agency, marked World TB Day by reiterating the need for improved TB diagnostics. In 2004, MSF provided TB treatment to 16,500 patients with TB. MSF’s TB adviser, Dr Francine Matthys, said that there was an urgent need for “a simple test which yields results almost instantly and can be used by any laboratory technician, nurse or health workers even when far away from a laboratory.”
Diagnosing TB in resource limited countries still relies on sputum microscopy, a diagnostic method that was developed in the 19th century. This test is only capable of detecting TB bacteria in 45-60% of all people who have TB, and is even less effective for individuals who have both HIV and TB – over 30% of the nearly 40 million people living with HIV/AIDS globally.