Investigating Interactions between HIV Infection and Tropical Diseases

The health of developing country populations in Africa where there is a high incidence of human immunodeficiency virus (HIV) infection is already seriously compromised by malnutrition and endemic diseases such as tuberculosis. Not only may HIV infection compromise currently used methods for the treatment of tropical diseases, but there may be a synergistic relationship between HIV and other diseases. Epidemiologic studies are thus needed to identify and quantify and such interactions. At present, evidence of such interactions may be limited by the fact that tropical diseases are most prevalent in rural areas while HIV cases have so far been concentrated in urban areas. However, any unexplained rise in the incidence or severity of a specific disease in areas where HIV is prevalent should be investigated as a possible interaction effect. Likewise, if the progression from HIV infection to acquired immunodeficiency syndrome (AIDS) seems to be occurring particularly rapidly in an area, AIDS patients should be examined for the presence of other diseases that may be triggering AIDS. Possible interactions between HIV infection and tropical diseases can be set forth in a schematic form in which both are divided into 3 infection states--uninfected, infected without clinical symptoms, and infected and diseases--and arrows are used to represent the transitions between states and possible interactions.