High prevalence of Microsporidium infection in HIV-infected patients. 
Sixty-four patients infected with human immunodeficiency virus (HIV) participated in a study to determine opportunistic enteric pathogens and compare them with the patients' clinical status.  The most frequently found pathogens were microsporidium (81.2%), Cryptosporidium parvum (20.3%), Candida albicans (12.5%) and Blastocystis hominis (10.9%).  Less frequently found pathogens were Giardia intestinalis (6.2%), Cyclospora (4.7%), Opishorchis viverrini ova (3.1%), Strongyloides stercoralis larvae (3.1%) and hookworm ova (1.6%).  The presence of enteric pathogens was not significantly associated with sex, length of HIV seropositivity and diarrheal symptoms.  A high prevalence of microsporidium, based on microscopic examination, was found in Thai HIV-infected patients.  This confirms the importance of microsporidium in HIV-infected/AIDS patients and the necessity for stool evaluation in all HIV-infected patients.