Currently, South Africa has the largest number of people living with HIV in the world and is also experiencing a dramatically expanded tuberculosis epidemic. These two epidemics are tightly linked, as HIV increases TB risk and disease, and TB is the leading cause of death among people living with HIV. In 2002, the Yale AIDS Program began addressing the twin epidemics in KwaZuluNatal, the country's most populous and heavily burdened province.

The program—led by Yale professor Dr. Gerald Friedland, professor emeritus of medicine (infectious diseases), epidemiology, and public health, and South Africa colleagues—is based on a strategy of integrated TB/HIV diagnosis, care, and treatment intended to improve the outcomes of both diseases. The strategy was first implemented in Durban, the largest city in KwaZuluNatal and the third largest in South Africa.

Multiple drug resistant

Unfortunately, when the Yale and South African researchers analyzed the causes of death among those who died during their research, they discovered that 60% of the deaths were attributable to multiple drug resistant (MDR) or extensively drug resistant tuberculosis (XDR TB). The latter strain, had only been recently identified and was resistant to the most potent first- and second-line TB drugs, making it extraordinarily dangerous, said Friedland.

The recognition of XDR TB in the KwaZuluNatal patients led the Yale, U.S., and South African researchers to undertake a comprehensive epidemiologic and microbiologic prevalence study, which, according to Friedland, "uncovered a previously unrecognized underlying disastrous drug-resistant TB epidemic in South Africa."

"We were astonished and dismayed to learn that 40% of new TB patients had drug resistant TB, almost all were HIV co-infected, and among them 25% had XDR TB," Friedland said, noting that the mortality rate for these patients was close to 90%.

Incidence of HIV and TB

"Our group's findings received widespread international attention and publicity in both the lay media and medical literature and have called attention to the consequences of decades of neglect in tuberculosis diagnosis, drug development and treatment, and the amplifying effect of HIV on TB incidence and prevalence,"  said Friedland."

Added to these factors, he noted, was the absence of strategies to address TB and HIV co-infection, particularly in settings of high TB and HIV prevalence such as rural sub-Saharan Africa.

Shenoi said, "We learned that late presentation to care resulted in ongoing transmission of both diseases and that efforts in the community, not just health care facilities, was essential  to reversing the epidemics."

HIV and TB strategy

The integrated HIV and TB strategy today includes offering training and deploying community health care workers to perform disease screening; decentralizing TB care; expanding strategies for reaching "hard to reach" populations.

It also includes strengthening points along the care continuum, including improving medication adherence, retention in care, and a more recent focus on implementing prevention tools including isoniazid preventive therapy to reduce TB incidence and pre-exposure prophylaxis to reduce HIV transmission risk.

Researchers said:  "Working on the ground in rural KwaZuluNatal, we appreciate that another epochal advance and reaching the aspirational WHO goals and strategy of eliminating the HIV and TB epidemics by 2030, will not be accomplished without surmounting enormous remaining scientific, clinical and public health challenges."

"Lastly, of critical importance is the long-term commitment, political will and financial resources to address and to alleviate the social determinants which lie at the root of these intertwined epidemics."