Intestinal microsporidiosis in HIV infected patients with chronic diarrhea in Thailand.

Microsporidia have been recognized as emerging opportunistic agents affecting multiple organs. Intestinal microsporidiosis caused by Enterocytozoon bieneusi and Encephalitozoon intestinalis is a common disease which is associated with gastrointestinal symptoms, particularly in AIDS patients. So far, information on the frequency of this enteric disease in Thailand is not available. Therefore, the present study was undertaken to investigate the prevalence of intestinal microsporidiosis in HIV infected persons with chronic diarrhea. From 1995 to 1996, multiple diarrheal stool specimens were received and examined for the presence of the organism using Weber's modified trichrome staining method and transmission electron microscopy for confirmation. Twenty-two of 66 patients (33.3%) were positive for microsporidia which appeared as pink-red spores of 0.8-1.2 x 0.7-0.9 microm with the characteristic transverse or oblique band representing the coiled polar filament. Clinical features of these patients included chronic diarrhea (100%), weight loss (100%), abdominal pain (77%), fever (36%), vomiting (36%) and anorexia (18%). Transmission electron microscopic examination of fecal specimens from the 22 patients with positive staining results revealed E. bieneusi in 18 cases.