Human Intestinal Flukes Haplorchis taichui and Haplorchis pumilio in their Intermediate Hosts, Freshwater Snails Family Thiaridae in Thailand

The intestinal flukes Haplorchis taichui (Nishigori, 1924) and Haplorchis pumilio (Looss, 1899) (family Heterophyidae) are among the most important food-borne parasitic zoonoses found in Southeast Asia. Here, the infection rates of freshwater snails family Thiaridae in Thailand were reported. The snails were collected by handpicking and scooping every two months for one year at several locations between December 2004 and September 2009. The snail samples were examined for parasitic infections in the lab by shedding and crushing methods. Parasite infections were found in snails from 66 of 126 sampling sites. Six species of thiarid snails were collected in this study, viz. Melanoides tuberculata (Muller, 1774) Melanoides jugicostis (Hanley & Theobald, 1876), Thiara scabra (Muller, 1774), Sermyla riqueti (Grateloup, 1840), Neoradina prasongi (Brandt, 1974) and Tarebia granifera (Lamarck, 1822). Five species (M. tuberculata, T. scraba, T. granifera, S. riqueti and N. prasongi) were found to be infected with H. taichui, while four species (M. tuberculata, M. jugicostis, T. scraba and S. riqueti) were found to be infected with H. pumilio. The infection rates of H. taichui and H. pumilio were 0.22% (133/59,884) and 1.03% (619/59,884), respectively.