Epidemiology of Intestinal Parasitic Infections among Karen School Children on the Western Border of Thailand

Abstract

Abstract

We studied the stool samples of 701 school children from three primary schools near theThai-Myanmar border, in Suanphung District, Ratchaburi, Thailand, to determine theprevalence and intensity of intestinal parasitic infections in August and September, 2005. The samples,49.4% male and 50.6% female were examined using the Kato-Katz technique to detect helmintheggs, and simple smear method to detect protozoa. The intensity of infection was categorized aslight, moderate or heavy according to the thresholds set by the World Health Organization. Theresults revealed a helminth infection rate of 40.8%, while protozoa infections accounted for 26.4%,mixed infections were common, resulting in a total prevalence of both parasites of 55.1%. The mostcommon infection was hookworm (24.5%) followed by trichuriasis (22.4%) and ascariasis (7.9%).The protozoal infections were Entamoeba coli (14.1%), Giardia intestinalis (8.4%), Endolimax nana(4.9%), E. histolytica (2.6%) and Cyclospora cayetanensis (0.1%). The prevalence rates of trichuriasisand ascariasis infections were significantly different among the three schools. Males were morefrequently infected with hookworm (30.4%) than females (18.9%), but no significant difference inprevalence rates for both sexes were observed for whipworm and roundworm infections. Theprevalence rates of hookworm tended to increase among the age group of 12-16 years (41.4%).Roundworm infections were more common among those aged <12 years, with the highest prevalencerate among children in the age group 8-11 years (10.0%). Hookworm and trichuriasis infectionsamong Karen children were significantly higher than Thai, and children from other ethnic groups(p < 0.05). More than 80% of individuals with hookworm and trichuriasis had light infections.Among those with ascariasis, 10.9 and 49.1%, had moderate and heavy infections, respectively.Heavy infections with ascariasis were frequently observed in children aged 4-7 years.

Keywords: epidemiology; intestinal parasitic infections; Karen; school children; western border; Thailand