Discovery of Carcinogenic Liver Fluke Metacercariae in Second Intermediate Hosts and Surveillance on Fish-Borne Trematode Metacercariae Infections in Mekong Region of Myanmar.

Ei Ei Phyo Myint,Amornpun Sereemaspun,Choosak Nithikathkul,Joacim Rocklöv

doi:10.3390/ijerph17114108

Abstract

Countries of lower Mekong regions are highly alarmed by the spread of fish-borne trematode infections, i.e., small liver flukes and minute intestinal flukes especially in Thailand, Lao People’s Democratic Republic (Lao PDR), Vietnam, Cambodia and Myanmar. Moreover; the incidence of cholangiocarcinoma has also been increasing in the endemic area of liver fluke infections. Only a few reports have been published concerning the fish-borne trematodes infections in the central region of Myanmar. However; there is still a lack of information regarding the status of trematodes infections in second intermediate hosts in the Mekong region of Myanmar. Therefore, we conducted surveillance on the distribution of trematode metacercariae in small cyprinoid fishes collected from the Mekong region of Myanmar. A total of 689 fishes (12 different species of cyprinoid fishes) have been collected and examined by pepsin digestion methods. We discovered four species of fish-borne trematode metacercariae infections, i.e., carcinogenic liver fluke, Opisthorchis viverrini; minute intestinal flukes, Haplorchis taichui; Haplorchis pumilio and Haplorchoides sp. in Tachileik, the Mekong Region of Myanmar. The outcome of this study could be a useful index for the fish-borne zoonotic trematode epidemiology in the Mekong area. Besides, the results of our study contribute to filling the gap of information necessary for the control and prevention of fish-borne trematode zoonotic infections in the Mekong region.

Highlights

The important public health problem of the spread of fish-borne trematodes (FBT) has highly alarmed the countries of the lower Mekong basin especially Thailand, Lao People’s DemocraticRepublic (Lao PDR), Cambodia, Vietnam and Myanmar [1,2,3,4,5]
In the total of 689 fishes, 391 fishes were infected with the fish-borne trematode infections, and the overall prevalence was 46.29%
This study demonstrates the existence of the life cycles of four species of fish-borne trematode infections around Tachileik, the Mekong region of Myanmar

Summary

Introduction

The important public health problem of the spread of fish-borne trematodes (FBT) has highly alarmed the countries of the lower Mekong basin especially Thailand, Lao People’s DemocraticRepublic (Lao PDR), Cambodia, Vietnam and Myanmar [1,2,3,4,5]. The important public health problem of the spread of fish-borne trematodes (FBT) has highly alarmed the countries of the lower Mekong basin especially Thailand, Lao People’s Democratic. Fish-borne zoonotic trematodes (FZT) especially small liver flukes (Opisthorchiidae) and minute intestinal flukes (Heterophyidae) are highly prevalent in those regions [6]. These two flukes have similar life cycles involving two intermediate hosts [7,8]. Humans are infected through ingestion of undercooked or raw freshwater fishes, which are contaminated with the infective stage of the parasite, i.e., metacercariae [11]. The traditional habit of eating raw or undercooked fish is a known risk factor for human trematode

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Conclusion