Blastocystis hominis: laboratory identification and clinical relevance

ABSTRACT

A total of 350 stool specimens from outpatient populations with gastrointestinal symptoms and 100 specimens from asymptomatic controls were examined for B. hominis and other associating parasites. Methods for preparation and staining of B. hominis were described. It was detected in 57 [16.3%] of the symptomatic patients and was the sole parasite in 39% [11.1%] of them. Among asymptomatic controls, it was detected in 10% and was the only parasite in 8% of them. Diarrhoea [71.8%] y specially mild and recurrent form was the most significant presenting symptom followed by flatulence [66.7%] and abdominal pain [60%]. Concomitant infection with other pathogenic parasites resulted in additional presentation with anorexia [38.9%], nausea and vomiting [27.8%] and tenesmus [27.8%]. Heavy infection [>5 organisms/HPF] was significantly associated with acute presentation of symptoms. Preliminary epidemiological features indicated a significant peak of incidence at ages 21-40 years and a male female ratio of 1 1.3. Possible spread within families was suspected. This study shows that B. hominis is a common finding in stool specimens and it should be included in the investigation of gastrointestinal disorders