Cases of extremely drug-resistant tuberculosis (XDR-TB) are being diagnosed throughout South Africa and could be going undetected in other parts of the region.
This emerged at a two-day workshop convened in Pretoria this week at the urgent request of the South African Health Department, attended by experts from the World Health Organisation (WHO), and health ministers and scientists from the Southern African Development Community (SADC).
The aim of the meeting was to develop an emergency action plan for controlling the spread of the deadly strain. XDR-TB poses a particularly serious threat to this part of the continent, where HIV prevalence is the highest in the world.
In a telephone interview with PlusNews, Paul Nunn of the WHO's Stop TB Department confirmed that HIV-positive people were much more susceptible to XDR-TB infection, and that the disease progressed more rapidly in such patients. "This means you need to be much quicker in your diagnosis and treatment, and you can't afford to make any mistakes in treatment."
So far over 100 cases of XDR-TB have been detected in the country, most of them in KwaZulu-Natal Province on the east coast, while none have been reported elsewhere in southern Africa. Prof Ronnie Green-Thompson from the Department of Health pointed out that South Africa was one of only a handful of countries on the continent with the equipment and technical knowledge to diagnose the deadly strain.
"We don't know the prevalence of XDR-TB in the rest of Africa because other countries don't have the capacity to do the tests, so it's not that South Africa is polluted, it's that South Africa has the diagnostic equipment."
Part of the WHO's response to the crisis will involve equipping other countries in the region to diagnose cases of the resistant strain. "It's not just a question of flying in some equipment but of improving the capacity of laboratories, training staff and changing policies, so it will take time," Nunn said.
As an emergency measure, the WHO will conduct rapid surveys, using laboratories in other countries if necessary, to determine the size and extent of the epidemic and the role of HIV; patients not responding to a first course of TB treatment, particularly those who were HIV-infected, would be tested for the XDR strain.
Workshop participants also discussed the need to strengthen existing TB programmes. About 250,000 new TB cases are diagnosed in South Africa each year, but only about 53 percent are cured. Drug-resistant TB arises when patients with ordinary TB fail to complete the six-month course of medication.
Most countries, including South Africa, have adopted the Directly Observed Treatment, Short-course (DOTS) strategy for TB drug adherence, in which patients are closely monitored to make sure they complete the course of drugs, but Nunn said implementation was often lacking.
"Part of this, of course, is because of the burden of HIV, which has multiplied the number of TB cases by five or six times, and public health services haven't been able to keep up with that rate of increase," he said.
Green-Thompson dismissed the possibility of introducing quarantine measures to prevent XDR-TB from spreading in South Africa, while Nunn took the view that complete isolation should only be used as a last resort for patients who refused treatment, but added that the WHO does provide a legal framework for this.
Despite the high death rate from XDR-TB in South Africa - to date 74 of the 78 patients confirmed with XDR-TB in KwaZulu-Natal have died - Nunn told PlusNews that the infection was "most likely" treatable with a combination of four drugs: two are already available in South Africa and the other two were recently imported, but they would need to be prescribed under highly controlled conditions to avoid further drug resistance developing.
Implementing the workshop recommendations will depend to a large extent on the resources available. "The WHO can provide the expertise and the knowledge, but international development agencies or governments will need to come up with the commodities and the funding," Nunn said.
He added that the Global Fund to Fight AIDS, Tuberculosis and Malaria had agreed to requests by grant recipients to redirect existing funds towards combating XDR-TB, and that the US-backed President's Emergency Plan for AIDS Relief was considering similar requests.