RESUMO
A total of 1 368 bedbugs of the species Cimex lectularius L were collected mainly from huts in villages or on farms at 6 localities in the northern Transvaal. They were tested in pools of 10 for the presence of hepatitis B surface antigen (HBsAg). None of 20 pools from Pietersburg was HBsAg-positive, but 32 out of 120 pools from the 5 other localities were HBsAg-positive. Estimated infection rates per 1 000 bugs were 17,1 (Messina), 24,9 (Waterpoort), 28,4 (Letaba), 54,5 (Potgietersrus) and 67,0 (Louis Trichardt), with an overall rate of 30,6. Seventeen out of 57 pools of the engorged bugs (infection rate 34,8) and 14 out of 62 pools of the unengorged bugs (infection rate 25,3) were HBsAg-positive. These very high infection rates, even in unengorged bugs, suggest that C. lectularius could be a vector of hepatitis B virus in the Transvaal, and that the varying degrees of infestation could explain the markedly different HBsAg-positive frequencies previously shown in sera collected from different population groups in that province.