Abstract

GUZMAN DE RONDON, Carmen et al. Biological behavior of Blastocystis hominis in patients treated with Secnidazol (Unidazol^®). Rev. Soc. Ven. Microbiol. [online]. 2008, vol.28, n.1, pp.66-71. ISSN 1315-2556.

Blastocystis hominis, classified as Stramenopile, is the most frequent intestinal parasite in humans. In feces and cultures, forms with a central body (FCB), granulose forms (GraF), as well as globulous and ameboid forms in binary division or in cysts are seen. Its elevated prevalence, association with symptoms in humans, and lack of effective treatment, justified the evaluation of secnidazol (Unidazol ® ZOUZ-PHARMA) in 14 individuals (7 males and 7 females) infected with B. hominis, with ages between 5-79 years, who were clinically and parasitologically evaluated before and after treatment; with one dose of the drug: 2 g for adults and 30 mg/Kg body weight for children. In feces serial examinations we evaluated morphology, number of parasites per microscopic field (400X), reproductive forms, and growth in culture. The study showed that in 14.3% (2/14) of patients the parasite was eliminated, and there was a significant decrease of the number per field (p< 0.05), of the FCB (p= 0.001) and of GraF (p< 0.05) frequency in the rest, as well as a decrease of positive direct examinations (p< 0.001). These preliminary results show that the drug in a single dose occasionally eradicated B. hominis, decreased the excretion of vegetative forms and induced the occurrence of cysts.These studies should be continued.

Keywords : Blastocystis hominis; blastocytosis; secnidazol; antiprotozoa.