Dysentery in patients infected with human immunodeficiency virus in Zimbabwe: an emerging role for Schistosoma mansoni and Escherichia coli O157?

Information on bloody diarrhoea in HIV-positives is scarce. A prospective study was therefore performed, in Zimbabwe, to determine and compare the pathogens associated with bloody diarrhoea in 25 antiretroviral-naïve HIV-infected patients and 15 non-HIV-infected patients. Stool cultures and colonic biopsies were performed. Shigella was isolated from 18 (45%) of the subjects, Schistosoma mansoni from eight (16%), Escherichia coli H7:O157 from three (8%) and Campylobacter jejunii from two (5%). There was no evidence of Salmonella, Entamoeba histolytica or cytomegalovirus infection. Shigella dysenteriae type-1 occurred more often in the HIV-negatives than the HIV-positives (P = 0.02). Although HIV-associated bloody diarrhoea in Zimbabwe appears to be most frequently caused by Shigella, it may also be commonly the result of infection with Sc. mansoni or shiga-toxin-producing E. coli. A larger study specifically to examine the role of Sc. mansoni and E. coli O157 is warranted.