Intestinal Parasitoses among Hilltribe People and Soil Contamination in Nan Province, Northern Thailand

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Wanna Maipanich
Nirun Itiponpanya
Wichit Rojekittikhun
Chutatip Siripanth
Somchit Pubampen
Surapol Sa-nguankiat
Chun Juntanavivat
Tassanee Sukosol



Hilltribe people in the north of Thailand reside in mountainous areas. In Nan Province, these people inhabit hill-side and plain areas, keeping the highlands for agriculture. Tropical climate, clustered housing and the traditional lifestyle of the people intensify the transmission of intestinal parasitic diseases in the area. When residents are parasitized and contaminate the land with their feces, the soil around the households becomes a source of infection. In this study, the prevalence rates of intestinal parasitic infections among 453 hilltribe people were assessed by fecal examination using simple direct smear, DMSO Modified Acid Fast staining, Kato-Katz’s modified thick smear and polyethylene tube cultivation methods. Contamination of soil samples with fecal matter was studied by sugar flotation technique. Fecal examination showed that the hilltribe people in Nan Province had protozoan infections with Giardia lamblia (3.5%), Entamoeba coli (7.5%), and Endolimax nana (0.2%), none of them was detected for Cryptosporidium parvum and 38.0% of the population had helminthic infections. Major helminthic infections detected in this study were Necator americanus (30.7%) and Ascaris lumbricoides (13.9%). For Trichuris trichiura, Enterobius vermicularis, Taenia spp, Opisthorchis viverrini and minute intestinal fluke; detection rates were only 0.2% for each infection.

The prevalence rate of helminthic infection among hilltribe people in Muang District was higher than the group from Pua District and soil samples collected around the household of Muang District also showed positive findings for A. lumbricoides eggs. Since the prevalence rate of hookworm infection in both districts were significant, 22.4% in Pua District and 39.4% in Muang District, the hilltribe group should be considered as a risk group or target group in the Intestinal Helminthiosis Control Program in Thailand.

Keywords : hilltribe, intestinal parasitic infections, soil contamination

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