Sintomatología y factores epidemiologicos asociados al parasitismo por Blastocystis hominis

To contribute to the knowledge of symptoms and factors associated with the infection by Blastocystis hominis of patients attending the outpatient clinic of the Department of Enfermedades Transmisibles y Dermatologicas (DETD) of the Hospital Nacional Cayetano Heredia. A prospective case-control study was carried out from January to March 1999, in patients between the ages of 5 to 80 years. The case-patients had a positive stool examination for B. hominis (in the absence of other pathogens such helminths) done at the laboratory of Tropical Medicine. The controls had at least 2 of 3 negative fecal samples of B. hominis, in absence of other pathogens. The presence of B. hominis was examined under direct microscopy (high-power field x 400) and it was rated from 1 plus to 4 plus according to the quantity of parasites present. Epidemiological data, symptomatology and the factors associated with infection in each patient were registered A total of 144 persons (74 cases and 70 controls) matched by age and sex were included in the study. A significant statistical correlation (p < 0.05) was found between the presence of B. hominis and the presence of symptoms (91.9%). The predominant symptoms in order of significance (p < 0.05), associated to the infection by B. hominis were: abdominal pain (OR = 3) 1.47 < OR < 6.60, abdominal distention (OR = 2.36) 1.06 < OR < 5.29, urticaria (OR = 3.19) 0.81 < OR < 12.48. The only risk factor found associated with the infection with B. hominis, was the consumption of raw unboiled water (OR = 2.52) 1.01 < OR < 5.83