Prevalence patterns of intestinal parasitoses among school children in Mahaweli System C: a new settlement in Sri Lanka

Abstract

SUMMARY: Studentsattending three schools in the settlements of Bakmeedeniya, Ranhelagama and Nagaswewa in Mahaweli System C, were examined at approxi¬mately yearly intervals from December 1986 to November 1989, to assess the prevalence patterns of intestinal parasitoses in the area. The age of the students at the time of examination ranged from 5-19 years, with 89% being in the 5-14 year age group. The male:female ratio was 1:1.1. Faecal smears in saline and iodine were examined for protozoan cysts and helminth ova. Children positive for pathogens were given appropriate therapy. A total of 765 stool samples (from 496 children) were examined: 203 in 1986/87, 365 in 1988 and 197 in 1989. The prevalence of the soil-transmitted helminths was very low throughout, and the rates facAscarislumbricoides, Trichuristrtehiura and hookworm infection was always less than 4 %. Of the intestinal protozoan parasites, the cysts most commonly seen were those of Entamoeba coli, which was found at rates of 16%, 13% and 10% in 1986/87,1988 and 1989 respectively. The commonest pathogenic protozoan was however Giardia intestinalis (positivity rates: 10%, 10% and 8% respectively). lodamoeba butschlii was also detected at low levels, the rates being 3%, 1 % and 2% respectively. E. histolytica was not seen.