Effect of antiretroviral therapy on cryptosporidiosis and microsporidiosisin patients infected with human immunodeficiency virus type 1

To better understand whether potent antiretroviral therapies can modify the natural history of HIV-1-associated microsporidiosis and cryptosporidiosis , the response to antimicrobial treatment of these opportunistic infections was evaluated in patients with or without antiretroviral treatment. Fifty patients with diarrhoea, all positive for Cryptosporidium parvum or Enteroc ytozoon bieneusi, were included in the study. Retrospective data were colle cted concerning demographics, clinical and microbiological characteristics of the parasitic infection, antiretroviral therapy and prophylaxis against opportunistic infections. Faecal samples were prepared using the Richie for malin-ethyl acetate method and stained using the modified Ziehl-Neelsen met hod for detection of Cryptosporidium parvum and Isospora belli, the modifie d trichrome and calcofluor white technique for detection of Enterocytozoon spp., and iodine for detection of ova, cysts or vegetative forms. Diarrhoea was defined as an abnormal increase in stool liquidity, an abnormal increa se in stool frequency and a daily stool weight of more than 250 g for a per iod of at least 4 days. Patients treated with double antiretroviral therapy or protease inhibitors demonstrated an excellent response and a sustained therapeutic effect after follow-up (range, 5-36 months). The relapse of cry ptosporidiosis in two patients who discontinued antiretroviral therapy sugg ests that the infection might remain in a latent stage. The resolution of t he diarrhoea seems to be related to an increased CD4+ cell count rather tha n to the viral load. In conclusion, these data strongly support the hypothe sis that combination antiretroviral therapy is able to greatly modify the c ourse of cryptosporidiosis and microsporidiosis in patients infected with H IV-1.