Infectious diseases in Africa.

Abstract

As a result of inadequate surveillance systems and definitive diagnostic standards, it is impossible to quantify the incidence and true pattern of infectious diseases in Africa. Nonetheless, it is clear that viral, bacterial, spirochetal, protozoal, helminthic, and mycotic infections contribute the greatest proportion of health afflictions among all age groups and population subgroups. Particularly alarming is the high prevalence of viral hepatitis in tropical Africa. By the age of 30 years, 70-90% of Africans show indications of past or current hepatitis B virus infection. Scarification, blood sucking vectors, sexual intercourse, and multiple uncontrolled injections are considered the major risk factors associated with this infection, which appears to be etiologically related to primary liver carcinoma. At least 25% of children born to mothers with antigens to hepatitis B become infected. Hepatitis B immunization--demonstrated to be safe and effective in infants as well as adults--is the best strategy to curb the infection rate. Human T-cell lymphotropic retroviruses have a higher prevalence in Africa than any other continent and are linked to T and B-cell neoplasia. In terms of human immunodeficiency virus (HIV) infection, a minimum of 5-10 million Africans are infected and there are well over 100,000 cases of acquired immunodeficiency syndrome (AIDS). The major risk factor for HIV infection is heterosexual promiscuity. Another problematic infection is Lassa fever virus, which can reach epidemic proportions but has not led to significant mortality.