Helminth and intestinal protozoa infections, multiparasitism and risk factors in Champasack province, Lao People's Democratic Republic.

Somphou Sayasone,Kongsap Akkhavong,Penelope Vounatsou,Monely Vanmany,Tippi K Mak,Jürg Utzinger,Oroth Rasphone,Peter Odermatt,Jeffrey Michael Bethony

doi:10.1371/journal.pntd.0001037

Abstract

BackgroundDetailed investigations of multiparasitism are scarce in the Mekong River basin. We assessed helminth (trematode, nematode, and cestode), and intestinal protozoa infections, and multiparasitism in random population samples from three different eco-epidemiological settings in Champasack province, southern Lao People's Democratic Republic (Lao PDR), and determined underlying risk factors.MethodologyTwo stool samples were collected from 669 individuals aged ≥6 months over consecutive days and examined for helminth infections using the Kato-Katz method. Additionally, one stool sample per person was subjected to a formalin-ethyl acetate concentration technique for diagnosis of helminth and intestinal protozoa infections. Questionnaires were administered to obtain individual and household-level data pertaining to behavior, demography and socioeconomic status. Risk factors for hepato-biliary and intestinal parasitic infections and multiparasitism were determined using multiple logistic regressions analyses.Principal FindingsMultiple species intestinal parasite infections were common: 86.6% of the study participants harbored at least two and up to seven different parasites concurrently. Regarding nematode infections, hookworm was the most prevalent species (76.8%), followed by Ascaris lumbricoides (31.7%) and Trichuris trichiura (25.0%). Regarding trematodes, Opisthorchis viverrini and Schistosoma mekongi infections were found in 64.3% and 24.2% of the participants, respectively. Infections with intestinal protozoa were rare.Conclusions/SignificanceThere is a pressing need to intensify and sustain helminth control interventions in the southern part of Lao PDR. Given the high prevalence with nematode and trematode infections and the extent of multiparasitism, preventive chemotherapy is warranted. This intervention should be coupled with health education and improved access to clean water and adequate sanitation to consolidate morbidity control and enhance sustainability.

Highlights

Lao People’s Democratic Republic (Lao PDR) is a landlocked country situated in the Great Mekong sub-region of Southeast Asia, where socioeconomic and eco-epidemiological characteristics vary greatly according to location
We report results obtained from an in-depth study of hepato-biliary and intestinal multiparasitism and associated risk factors in three settings of the most southern province of Lao People’s Democratic Republic
Of particular concerns are the high prevalence of the liver fluke Opisthorchis viverrini (64.1%) and the moderate prevalence of the blood fluke Schistosoma mekongi (24.2%), as these fluke infections are responsible for severe hepato-biliary morbidity, including the bile duct cancer cholangiocarcinoma

Summary

Introduction

Lao People’s Democratic Republic (Lao PDR) is a landlocked country situated in the Great Mekong sub-region of Southeast Asia, where socioeconomic and eco-epidemiological characteristics vary greatly according to location. China) with mountains and highlands dominating the landscapes These topological features are natural barriers that might impede social and economic development, since transportation of commodities, communication and other exchanges are hampered. These issues exacerbate people’s access to health care, clean water and adequate sanitation. We assessed helminth (trematode, nematode, and cestode), and intestinal protozoa infections, and multiparasitism in random population samples from three different eco-epidemiological settings in Champasack province, southern Lao People’s Democratic Republic (Lao PDR), and determined underlying risk factors

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Results

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Conclusion