Contamination of soil with parasite eggs in Surabaya, Indonesia

Soil was examined for contamination by parasite eggs in Surabaya Indonesia. Surveys were carried out on three occassion; July, 1993 (dry season), March, 1994 (rainy season), and August, 1994 (dry season). Throughout the study, five species of nematode eggs (Ascaris lumbricoides, Toxocara cati, Trichuris trichiura, Physaloptera sp, Capillaria sp), two species of cestode eggs (Hymenolepis diminuta, Spirometra erinacei), and one species of protozoa oocyst (Isospora felis) were detected. The contamination rate and number of species found from the soil were significantly different in the dry and rainy seasons. In the dry season, the prevalence was 8-20%, with two to four species detected. During the rainy season, this rate was 83% with eight species, suggesting parasite infection to possibly occur mainly in this season. The reason for this seasonal difference may be that, in spite of constant temperature around 27 to 29 degrees C throughout the year, rainfall in the dry season in only a few percent of that of the rainy season. We concluded that parasite eggs die during the dry season owing to dryness of the soil. Contamination of soil with parasite eggs and the number of species found were greater in alley-ways and at communal water supply sites around residential areas than in open-air parks or sandy beaches. The method used in the present study proved extremely effective for ascertaining the actual dynamics of parasite infection in a certain region.