Epidemiological situation and molecular identification of cercarial stage in freshwater snails in Chao-Phraya Basin, Central Thailand

Molecular confirmation of trematodes in the snail intermediate hosts from Ratchaburi Province, Thailand

“…Digenetic trematodes, particularly intestinal and liver flukes, are widely distributed in many Asian countries including Korea, Vietnam, Myanmar, Cambodia, Laos and Thailand, and remain a public health problem throughout the region [1][2][3][4][5][6][7]. The heterophyid trematode and some liver flukes can infect mammals and humans who eat raw or uncooked infected-fish species such as Haplorchis taichui (H. taichui) and Haplorchis pumilio (H. pumilio) [2,8,9].…”

“…This river is the primary source for several types of freshwater ecosystems, including irrigation canals, paddy fields and waterfalls. These water bodies provide suitable conditions for cercaria and metacercaria development [1,18].…”

“…The internal transcribed spacer 2 (ITS2) of the 18S rDNA gene was selected and used in this study. This region can be used for the purposes of identification of various stages of minus intestinal trematode (cercaria, metacercaria and adult stages) infections in their intermediate and definitive hosts [1,22,23]. Moreover, the sequences of the ITS2 region have been used as a potential molecular marker at the species or population level [24].…”

“…Molecular biological methods have been acknowledged as the most efficient and accurate tools that can be used for the identification of several parasitic organisms including trematodes [1,14,[19][20][21]. The internal transcribed spacer 2 (ITS2) of the 18S rDNA gene was selected and used in this study.…”

“…Freshwater snails and fish typically serve as the intermediate host in most instances [1,6,14,15]. These trematodes are endemic throughout the Southeast Asian region, including Thailand, Lao PDR, Vietnam, Korea and the Philippines [1,2,5,7,10,15], with a high incidence of mixed infections involving small liver trematodes and other minute intestinal trematodes [16,17]. The distribution of trematodes requires specific suitable ecological conditions, typically involving certain water resources such as those located in agricultural areas as well as rivers and irrigation canals.…”