Epidemiological Studies on Strongyloides stercoralis at Dilla District, Ethiopia

Abstract

Background and study aim: Some authors have accepted parthenogenesis or asexual reproduction and hermaphroditism (protandrogony) to be the only mode of reproduction of parasitic female Strongyloides stercoralis in human hosts as parasitic males of it did not exist in human hosts. Therefore, the first objective was to work out the infection rate of Strongyloides stercoralis in the population of elementary schools children at Dilla district; secondly, to produce a visible evidence for the presence of many parasitic males of Strongyloi-des stercoralis as there are parasitic femal-es in fresh stools samples of human hosts; and thirdly, to replace the unfit term by a correct one. Patients and methods: Stools samples were collected from student children of elementary schools, and observed under microscope in the laboratory of parasitology after employing Baermann apparatus technique. Results : In the study a total of 710 student children were examined for Strongyloides stercoralis infection out of whom 142 (in 1st study) were positive, confirming the infection rate to be 20% or 198 positive (in 2nd study) the infection rate being 28% by the parasite. Then, the average infection rate was 24%. All developmental stages and sexes of the parasite were obtained in the study executed. Conclusion : The presence of many parasitic males with everted spicules observed in fresh stools samples during this study had been a very strong evidence for the fact that male and female copulation & fertilization were naturally taking place among parasitic worms of Strongyloides stercoralis in human hosts. Parasitic and free living males of S.stercoralis have the same morphology including the curved or coiled posterior body part