HIV/AIDS-associated opportunistic protozoal diarrhea

Abstract

Human immunodeficiency virus (HIV) infection has altered both the epidemiology and outcome of enteric opportunistic parasitic infections. This study was done to determine the prevalence and species/genotypes of intestinal coccidian and microsporidial infections among HIV/AIDS patients with diarrhea and/or a history of diarrhea alternately with an asymptomatic interval, and their association with CD4 T cell count. This cross-sectional study was done from May 2010 to May 2011 in Shiraz University of Medical Sciences, South of Iran. A blood sample was obtained from HIV-positive patients for a CD4 T cell count upon enrollment. Sociodemographic data and a history of diarrhea were collected by interviewing 356 consecutive participants (273 males and 83 females). Whenever possible more than a fecal sample was collected from all the participants and examined for parasites using direct, physiological saline solution ethyl acetate, an acid-fast trichrome stain, nested polymerase chain reaction, and sequencing techniques for the detection, confirmation, and genotyping of Cryptosporidium spp., Cyclospora cayetanensis, Isospora belli, and intestinal microsporidia (Enterocytozoon bieneusi). The most common opportunistic and nonopportunistic pathogens were Cryptosporidium spp. (C. parvum and C. andersoni), E. bieneusi, Giardia lamblia, Sarcocystis spp., and Blastocystis homonis affecting 34, 8, 23, 1, and 14 patients, respectively. C. cayetanensis, I. belli, Enterobius vermicularis, and Hymenolepis nana were observed in few patients. A CD4 count <200 cells/μl was significantly associated with the presence of opportunistic parasites and diarrhea (p<0.05). Opportunistic intestinal parasites should be suspected in any HIV/AIDS patient with chronic diarrhea. Tropical epidemic nonopportunistic enteric parasitic infections among such patients should not be neglected in Iran.

FIG. 1.

Photomicrographs of fecal smears. (A) Oocysts of Cryptosporidium spp. in acid-fast stain (1000×). (B) Oocysts of Isospora belli in acid-fast stain (1000×). (C) Oocysts of Cyclospora cayetanensis in acid-fast stain (1000×). (D) Spores of Enterocytozoon bienusei in acid-fast trichrome (1000×). Color images available online at www.liebertpub.com/aid

FIG. 2.

PCR products of Isospora belli on electrophoresis on 1.5% agarose gel. Lane M: 100 bp DNA size marker. Lanes 1–2: negative and positive control, respectively. Lane 3: positive sample.

FIG. 3.

Detection of Cryptosporidium-specific fragments by nested PCR. Lanes: M, molecular marker; 1–3, positive samples; 4–5, negative and positive control samples, respectively. The molecular weight marker was a 100-bp ladder.

FIG. 4.

Nested PCR-amplified products of Enterocytozoon bieneusi from stool samples (M: 100-bp MW; lanes 1 and 2: negative and positive control, respectively; lanes 3–5: positive samples).

FIG. 5.

Nested PCR amplification of Cyclospora cayetanensis DNA. Lane M: molecular size markers; lanes 1 and 2: positive control and study specimen.