When in vitro cultivation was used as the 'gold standard' for the detection of Blastocystis hominis in stool specimens, simple smear and trichrome staining showed sensitivities of 16.7% and 40.2% and specificities of 94% and 80.4%, respectively. In vitro cultivation also enhanced PCR amplification for the detection of B. hominis in stool specimens. Our data show the usefulness of in vitro cultivation for the detection and molecular study of B. hominis in stool specimens.

Opisthorchis viverrini infection is one of the major public health problems in Thailand. Although information about transmission of this parasite to humans is well established, infections are still prevalent in the northern and northeastern Thailand. Thus, prospective epidemiologic information is needed for developing more effective public health interventions. A cohort study to identify incidence and risk factors of O. viverrini infection was conducted in a rural community in Thailand during December 2002-February 2004. The incidence rate of opisthorchiasis was 21.6/100 person-years. The independent factors associated with opisthorchiasis were an age > 60 years and consuming chopped raw fish salad (Koi pla). Thus, avoiding this raw fish salad should be emphasized in the national control program.

Stool samples from seven human immunodeficiency virus (HIV)-negative and two HIV-positive children with asymptomatic Enterocytozoon bieneusi infections were daily examined to quantify spore shedding using Gram-chromotrope staining under light microscopy. The spore shedding pattern and intensity in these children was variable. Mean spore concentrations in the stool samples from these children ranged from 2.4 × 102 to 1.2 × 105 spores per gram. Light microscopy could detect spores in stool specimens for 9–33 days, while PCR was able to detect E. bieneusi in stool specimens for 3–40 days longer. This suggests that light microscopy may not detect low levels of spore shedding. Considering that the asymptomatic group are a potential source of infection, detection methods with a higher sensitivity should be used.

In Thailand, it was not uncommon for dialysis patients to acquire viral hepatitis infections. However, our prevalence is similar to reports from some other South-East Asian countries.