Infection of encysted trematode metacercariae in Cyprinoid fish from the middle Mun-upper Chi River basin of Thailand, with micromorphological and molecular approach using

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Wiwat Sungkhabut
Taweechai Wisanuyothin
Nathkapach Rattanapitoon
Chatchawal Noiwangkang
Kulyanee Junthima
Chalermporn Devahastin Na Ayudhya
Kaitsuda Saiprom


The Cyprinoid fish play a crucial role in the distribution and proliferation of trematode metacercariae in the ecosystem. They also serve as significant intermediate hosts transmitting liver fluke diseases to humans. However, there is a lack of epidemiological surveillance data on the second intermediate host in the river basins of the at-risk areas of Nakhon Ratchasima, Buriram, Surin and Chaiyaphum provinces. Therefore, information on infection in disease reservoir hosts is essential. This study focuses on the infection of trematode metacercariae and aims to develop sentinel surveillance methods using micromorphological and molecular techniques. The study area encompasses 11 sub-districts in the middle Mun-upper Chi River basin of Thailand. A total of 813 fresh fish samples, representing four species of Cyprinoid fish, were collected. The samples underwent pepsin HCL digestion and were subsequently confirmed via PCR, revealing the presence of Haplorchoides sp. metacercariae in 5 sub-districts in Buriram province during the winter season, Opisthorchis viverrini (Ov) metacercariae in 2 sub-districts in Chaiyaphum province during the rainy season, and unknown metacercariae in 4 sub-districts in Nakhon Ratchasima, Chaiyaphum, and Surin provinces during the rainy season. Ov metacercariae were also found in 1 sub-district in Nakhon Ratchasima province during the rainy season. Micromorphological examination of Haplorchoides sp. metacercariae was performed, and illustrations were created as supporting references. This study emphasizes that Cyprinoid fish act as second intermediate hosts for many species of trematodes, and in the upper Chi River basin, there continues to be contamination with Ov metacercariae. The collaboration of local networks is crucial for monitoring the epidemic spread of intermediate hosts transmitting diseases to humans in the areas of regional health 9.

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Sungkhabut W, Wisanuyothin T, Rattanapitoon N, Noiwangkang C, Junthima K, Devahastin Na Ayudhya C, Saiprom K. Infection of encysted trematode metacercariae in Cyprinoid fish from the middle Mun-upper Chi River basin of Thailand, with micromorphological and molecular approach using. JMPH4 [Internet]. 2024 Jun. 11 [cited 2024 Jul. 23];14(2):148-57. Available from:
Original Articles


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