Opisthorchiasis pathogen distribution in floodplain-river systems of central Vietnam

A survey of water bodies of different hydrological regimes in 7 provinces of Central Vietnam was conducted for the presence of larvae of Bithyniidae molluscs and fish infested with trematode pathogens. Biotopes of Bithynia siamensis goniomphalos molluscs were found in rice fields, bypass canals and small rivers with low flow. No molluscs infested with Opisthorchis viverrini larvae were found. In fish, metacercariae of this helminth were found only in Puntius brevis in a community pond. Other fish in the surveyed natural water bodies were infested only with intestinal trematodes. It is reasonable to assume that circulation of the opisthorchiasis pathogen in wildlife is practically absent. Therefore, opisthorchiasis in the surveyed areas can be classified as a zooanthroponosis and its foci are located in fish farms and private water bodies of community farms. This determines the prevalence of opistorchiasis among the population in the lower reaches of rivers in the coastal provinces.

1. Leiper, R.T., 1915. Notes on the occurrence of parasites presumably rare in man. J. R. Army Med. Corps 24. 569–575.

2. Sripa, B., Kaewkes, S., Intapan, P.M., Maleewong, W., Brindley, P.J. 2010. Food-borne trematodiases in Southeast Asia epidemiology, pathology, clinical manifestation and control. Adv. Parasitol. 72, 305–350.

3. Yukifumi Nawa. Clonorchis sinensis and Opisthorchis spp. in Vietnam: current status and prospects. Trans R Soc Trop Med Hyg. 2016; 110: 13–20.

4. WHO. Review on the epidemiological profile of helminthiases and their control in the Western Pacific Region, 1997–2008, MVP/ WPRO, The Western Pacific Region, World Health Organization (2008).

5. Thanh D.N., Hai H.N. Freshwater Mollusca: Gastropoda and Bivalvia. In: Fauna of Vietnam. Vietnam Science and Technology Publisher; 2010.

6. Petney T.N., Taraschewski, H., 2011. Water-borne parasitic diseases: hydrology, regional development and control. In: Frimmel, F.H. (Ed.), Water Chemistry and Microbiology. Elsevier. Amsterdam. 303–366.

7. Ha Thanh Thi Dao, Veronique Dermauwc, Sarah Gabriëld, Apiporn Suwannatraie, Smarn Tesanae, Giang Thanh Thi Nguyenf, Pierre Dornyb. Opisthorchis viverrini infection in the snail and fish intermediate hosts in Central Vietnam. Acta Tropica. 170 (2017). 120–125.

8. Murrell K.D., Cong L.D., Cam P.D., Chau L.V., Toan N.D., Dalsgaard A. The foodborne trematode zoonoses of Vietnam. Southeast Asian J. Trop. Med. Public Health. 2003;4 (Suppl.):12-34.

9. Vo The Dung, Jitra Waikagul, Bui Ngoc Thanh, Dung Thi Vo, Duy Nhat Nguyen,and K. Darwin Murrell. Endemicity of Opisthorchis viverrini Liver Flukes, Vietnam 2011–2012. Emerging Infectious Diseases. www.cdc.gov/eid .Vol. 20, No. 1, January 2014. 152-153.

10. Sidorov Е.G., Natural foci of opisthorchiasis. Alma-Ata, Nauka. KazSSR, 1983; 240. in Russian.

11. Thanh Thi Ha Dao, Tuan Van Bui, Emmanuel Nji Abatih, Sarah Gabriël, Thanh Thi Giang Nguyen, Quang Hong Huynh, Chuong Van Nguyen, Pierre Dorny. Opisthorchis viverrini infections and associated risk factors in a lowland area of Binh Dinh Province, Central Vietnam. Acta Tropica.Volume 157, May 2016. 151–157.