TỈ LỆ NHIỄM SÁN LÁ SONG CHỦ TRÊN CÁ LÓC (Channa striata Bloch, 1793) Ở HUYỆN ĐỨC HUỆ, TỈNH LONG AN

Nghiên cứu trên 400 con cá lóc giai đoạn 2-4 tháng tuổi ở 20 ao nuôi ở huyện Đức Huệ, tỉnh Long An được thực hiện trong năm 2018. Kết quả phân tích cho thấy cá lóc trong nghiên cứu không bị nhiễm sán lá gan nhỏ. Nhóm tác giả đã xác định hai loài sán lá ruột nhỏ nhiễm trên cá lóc là Haplorchis pumilio và Centrocestus formosanus với tỉ lệ nhiễm chung là 2,8%. Loài metacercariae gây nhiễm nhiều nhất là sán lá ruột Haplorchis pumilo chiếm tỉ lệ 72,7%. Tỉ lệ nhiễm sán lá ruột nhỏ trên cá lóc nuôi ao ảnh hưởng bởi mùa vụ, lượng vôi bón, thời gian phơi đáy ao và nguồn thức ăn (P<0,05). Cần tiếp tục nghiên cứu tỉ lệ nhiễm sán lá song chủ trên các loài cá khác ở huyện Đức Huệ, tỉnh Long An để có thêm số liệu về tỉ lệ nhiễm trên cá, đồng thời cần có biện pháp kĩ thuật để giảm tỉ lệ nhiễm trên cá nuôi góp phần bảo đảm an toàn vệ sinh thực phẩm.

High Prevalence of Clonorchis sinensis and Other Zoonotic Trematode Metacercariae in Fish from a Local Market in Yen Bai Province, Northern Vietnam

A small survey was performed to investigate the recent infection status of Clonorchis sinensis and other zoonotic trematode metacercariae in freshwater fish from a local market of Yen Bai city, Yen Bai province, northern Vietnam. A total of 118 fish in 7 species were examined by the artificial digestion method on March 2016. The metacercariae of 4 species of zoonotic trematodes, i.e., C. sinensis, Haplorchis pumilio, Haplorchis taichui, and Centrocestus formosanus, were detected. The metacercariae of C. sinensis were found in 62 (69.7%) out of 89 fish (5 species), and their intensity of infection was very high, 81.2 per fish infected. Prevalences of 3 intestinal flukes, H. pumilio, H. taichui and C. formosanus, were 75.0%, 47.6%, and 31.7% in positive fish species, respectively, with the metacercarial intensities of 15.5, 10.3, and 2.2 per fish infected. From the above results, it has been confirmed that various species of freshwater fish continue to play the role of the infection source of C. sinensis and other zoonotic trematodes in Yen Bai city, Yen Bai province, northern Vietnam. It is of particular note that the prevalence and intensity of C. sinensis metacercariae are much higher than those reported in previous studies in fish in northern Vietnam.

Prevalence of trematode in wild fish from fishing in Ho Chi Minh City

A research on the prevalence of fishborne zoonotic trematodes (FZT), metacercariae stage, in wild fish from fishing in Nhieu Loc – Thi Nghe, Tau Hu – Ben Nghe and Thay Cai – An Ha canals was conducted in Ho Chi Minh City in the period of May 2017 and April 2018. The results showed that no metacercariae were found in fish in Nhieu Loc – Thi Nghe and Tau Hu – Ben Nghe canals. However, wild fish in Thay Cai – An Ha canal were infected with Haplorchis pumilio and Centrocestus formosanus. Metacecariae were infected in silver barb (80%), climbing perch (11.7%), snakehead (7.5%), and walking catfish (1.7%). The FZT prevalence in the wet season is significantly higher than in the dry season (P

Tỉ lệ nhiễm sán lá song chủ trên cá hô giống (Catlocarpio siamensis Boulenger, 1898) ở đồng bằng sông Cửu Long, Việt Nam

Nghiên cứu tỉ lệ nhiễm sán lá song chủ (giai đoạn metacercariae) trên 700 cá hô giống ở đồng bằng sông Cửu Long được thực hiện vào năm 2017. Kết quả cho thấy cá hô giống nhiễm metacercariae của hai loài sán lá ruột nhỏ Haplorchis pumilio và Centrocestus formosanus với tỉ lệ 2,4%. Tỉ lệ nhiễm ảnh hưởng bởi mùa vụ, lượng vôi bón và thời gian phơi đáy ao (P<0,05). Biện pháp kĩ thuật là cần thiết để giảm tỉ lệ nhiễm metacercariae trên cá giống, nhằm hạn chế tỉ lệ nhiễm trên cá hô thịt, góp phần bảo đảm an toàn vệ sinh thực phẩm.

Infection status and molecular identification of digenean cercariae in snails in Kim Son district, Ninh Binh Province and Ba Vi district, Ha Noi

In this study, the molecular method was used to identify digenean cercariae from freshwater snails in Kim Son District (Ninh Binh Province) and Ba Vi District Ha Noi. A total of 9 snail species were collected and examined for cercarial infection. Three snail species (Radix swinhoei, Angulyagra polyzonata and Pomacea canaliculata) were not infected, while the other 6 species (Austropeplea viridis, Gyraulus convexiusculus, Parafossarulus striatulus, Bithynia fuchsiana, Melanoides tuberculata and Tarebia granifera) were infected with digenean cercariae at low infection rates, ranging from 2.3% to 6.3%. Seven cercarial groups were identified: Echinostome, Monostome, Parapleurophocercaria, Xiphidiocercaria, Fucocercaria, Gymnocephalous and Megalurous. Snails M. tuberculata and P. striatulus were infected with 4 cercarial groups, A. viridis and G. convexiusculus snails were infected with 2 groups, 2 snail species B. fuchsiana and T. granifera were infected with one group of cercaria. The results of ITS2 sequences analyses of the cercarial groups identified the larvae of 9 trematode species, namely Echinostoma revolutum, Echinochasmus japonicus, Notocotylus intestinalis, Philophthalmus gralli, Haplorchis pumilio, Procerovum cheni, Fasciola gigantica, Australapatemon burti and Cyathocotyle prussica. Among them the last three species, P. cheni, A. burti and C. prussica, were found for the first time in Vietnam. In addition, the ITS-2 sequence of Gymnocephalous cercariae which was previously identified as Sphaeridiotrema monorchis, from P. striatulus snail was 97% similar to that of Sphaeridiotrema pseudoglobulus. Likewise, ITS-2 sequence of Echinostome cercaria from B. fuchsiana snail was 93% similar to that of E. japonicus and that of Xiphidiocercaria cercaria from M. tuberculata snail was 93% similar to Lecithodendrium spathulatum.

Infection status and molecular identification of digenean cercariae in snails in Kim Son district, Ninh Binh Province and Ba Vi district, Ha Noi

In this study, the molecular method was used to identify digenean cercariae from freshwater snails in Kim Son District (Ninh Binh Province) and Ba Vi District Ha Noi. A total of 9 snail species were collected and examined for cercarial infection. Three snail species (Radix swinhoei, Angulyagra polyzonata and Pomacea canaliculata) were not infected, while the other 6 species (Austropeplea viridis, Gyraulus convexiusculus, Parafossarulus striatulus, Bithynia fuchsiana, Melanoides tuberculata and Tarebia granifera) were infected with digenean cercariae at low infection rates, ranging from 2.3% to 6.3%. Seven cercarial groups were identified: Echinostome, Monostome, Parapleurophocercaria, Xiphidiocercaria, Fucocercaria, Gymnocephalous and Megalurous. Snails M. tuberculata and P. striatulus were infected with 4 cercarial groups, A. viridis and G. convexiusculus snails were infected with 2 groups, 2 snail species B. fuchsiana and T. granifera were infected with one group of cercaria. The results of ITS2 sequences analyses of the cercarial groups identified the larvae of 9 trematode species, namely Echinostoma revolutum, Echinochasmus japonicus, Notocotylus intestinalis, Philophthalmus gralli, Haplorchis pumilio, Procerovum cheni, Fasciola gigantica, Australapatemon burti and Cyathocotyle prussica. Among them the last three species, P. cheni, A. burti and C. prussica, were found for the first time in Vietnam. In addition, the ITS-2 sequence of Gymnocephalous cercariae which was previously identified as Sphaeridiotrema monorchis, from P. striatulus snail was 97% similar to that of Sphaeridiotrema pseudoglobulus. Likewise, ITS-2 sequence of Echinostome cercaria from B. fuchsiana snail was 93% similar to that of E. japonicus and that of Xiphidiocercaria cercaria from M. tuberculata snail was 93% similar to Lecithodendrium spathulatum.