Baseline Epidemiological Study of Malaria and Soil-transmitted Helminthiasis in Thai Rural Communities near the Myanmar Border

Abstract

Abstract

An analytic cross-sectional epidemiological study was conducted in January-March 2001 to measure the prevalence of malaria and helminthic infections, and to identify associated sociobehavioral risk factors in rural communities near the Thai-Myanmar border, in Suanphung, Ratchaburi Province, Thailand. A total of 2,898 individuals (85.7% of the total population) in two villages participated in the study. Of 2,280 individuals examined, 243 (10.7%) were positive for malaria. Among the positive cases, 129 (53.1%) were infected with Plasmodium falciparum, 109 (44.8%) with P. vivax and 5 (2.1%) with mixed infections. Males had significantly higher malaria prevalence (14.0%) than females (7.3%). Almost 56% of malaria cases occurred among those aged <16 years; and the highest prevalence was in the 4-15-year group. About 89% and 71% of the individuals in villages 4 and 6, respectively, stated that they always slept under mosquito nets; however, only 49% in village 6 possessed nets that were in good condition. The prevalence of malaria among those with damaged nets was 1.7 times higher than among those with nets in good condition. A total of 2,095 stool samples were collected and examined; more than half of the individuals (52.4%) were infected with at least one type of intestinal worm. The most common infection was hookworm (43.2%), followed by trichuriasis (15.9%), and ascariasis (13.2%). The prevalence of hookworm infection was significantly higher in village 6 (44.6%) than village 4 (39.1%); however, the prevalence of trichuriasis and ascariasis in village 4 was significantly greater than village 6. Males were more frequently infected with hookworm (47.0%) compared to females (39.1%), but no significant difference in prevalence between the sexes was observed for whipworm or roundworm. Ninety percent of individuals with hookworm and trichuriasis had light infections. Among those with ascariasis 40.1% and 12.7% had moderate and heavy infections, respectively. Heavy infections with ascariasis were frequently observed in children aged <7 years. About 13% and 31% of the households in villages 4 and 6 did not have latrines. In village 4, about 77% used latrines with septic tanks, with only 50% in village 6. Approximately one-third of individuals in village 6 defecated on the ground and 49% used paper/leaves or sticks to clean themselves after defecation.

Keywords: malaria; soil-transmitted helminthiasis; Thai-Myanmar border