Third Article in Lancet Series Examines HIV’s Interaction With Other Infectious Diseases in Africa
The third article in the Lancet's five-part series on AIDS in Africa this week examines how the AIDS epidemic has interacted with several other infectious diseases on the continent. Dr. Elizabeth Corbett of the London School of Hygiene and Tropical Medicine and colleagues specifically examined HIV's relationship with malaria, tuberculosis and sexually transmitted diseases. Summaries of their findings appear below:
- Malaria: Malaria has "consistently" been one of the top three causes of infant and child mortality in Africa; the World Health Organization estimates that malaria contributes to more than one million child deaths in Africa each year. Although HIV and malaria do not "crossreact" on HIV blood tests and HIV transmission by mosquitoes -- the primary mode of transmission for malaria -- has been "ruled out," malaria has indirectly contributed to the spread of HIV through unscreened blood transfusions to treat malaria-associated anemia. In addition, the authors note that the use of antimalarial drugs in patients who present with fever -- a common symptom of HIV infection, as well as other infections -- and who have unconfirmed malaria may increase resistance to such drugs, thereby worsening the malaria epidemic. HIV transmission through blood transfusions can be mitigated by instituting stronger blood safety measures, the authors state. They also call for malaria prevention efforts such as the use of insecticides and bed nets and conclude that more research needs to be conducted into how the two diseases interact.
- STDs: STDs, especially ulcerative STDS such as genital herpes, have "enhanced" the spread of HIV in Africa by "increasing the infectiousness of HIV-1-positive individuals and the susceptibility of HIV-1-negative individuals," the authors state. WHO estimates that sub-Saharan Africa has 69 million new curable STD cases annually among 15- to 49-year-olds, the highest incidence rate in the world. STD infection facilitates HIV transmission by "compromising mucosal integrity" through ulceration and inflammation, leaving people more infectious and vulnerable to infection. Diagnosing and treating STD cases in a timely manner is an "essential component of HIV-1 control," the authors state, adding that the promotion of safe sex and condom use should be included in any STD control program.
- Tuberculosis: Africa's TB epidemic has been exacerbated by the HIV/AIDS epidemic. The incidence of TB, one of the "most frequent" HIV-related illnesses and the leading cause of death among HIV-positive Africans, is expected to rise annually by about 10% in many of the continent's areas that are the worst-affected by HIV/AIDS. HIV infection increases the risk of latent TB infection "reactivation" and the risk of rapid disease progression in people recently infected or reinfected with TB. Prevention of reinfection and reactivation is "one of the key challenges" of controlling TB in Africa, as is preventing new infections. The directly observed therapy, short course strategy, or DOTS, has proven successful in treating TB; however, DOTS has "no element aimed at direct prevention of TB in high-risk individuals, and is not sufficient to contain TB incidence in the face of rising HIV-1 prevalence," the authors state, concluding that "commitment and funding on a hitherto unseen level" are needed to reduce the TB burden in Africa.