1.Opisthorchis viverrini metacercarial infection in cyprinid fish in Nakhon Phanom Province, Northeastern Thailand
Laoprom, N. ; Prathummang, S. ; Chuangchaiya, S. ; Navanesan, S. ; Munajat, M.B. ; Suwannatrai, A.T. ; Idris, Z.M.
Tropical Biomedicine 2021;38(No.2):25-30
Opisthorchiasis is endemic in parts of Southeast Asia, including the northern and
northeastern regions of Thailand. In these regions, the transmission by fish intermediate
hosts has received little attention. We investigated the intensity of Opisthorchis viverrini
metacercariae (OV MC) in wild cyprinid fishes from five districts within the Nakhon Phanom
Province, Northeast Thailand. Fishes were procured from local markets in five districts
throughout three different seasons (hot, rainy and cold) between February 2018 and January
2019. The samples were identified, counted and weighed before metacercariae detection
was performed via the artificial digestion method. A total of 2,149 freshwater fishes,
representing 20 species were collected. The fish most commonly contaminated with OV MC
were Anematichthys repasson and Hampala dispar. The intensity of OV MC in Nakhon Phanom
was 0.23 OV MC/fish and varied among districts, ranging from 0.07 to 0.52. A low intensity of
OV MC/fish (defined as <1 cyst) was found in all three different seasons in the Nakhon
Phanom Province; hot season (0.55), cold season (0.22) and the rainy season (0.13). The
intensity of OV MC/fish was moderate (defined as >1 cyst) in the Renu Nakhon district (2.5)
in the hot season. By fish species, H. dispar yielded the highest, with a moderate intensity of
2.1. In natural freshwater cyprinid fish in Nakhon Phanom, OV MC infection is endemic with
intensity rates varying according to district, season and fish species.