Prevalence and Intensity of Bothriocephalus acheilognathi in Tor putitora in Mahakali River, Nepal

Bothriocephalus acheilognathi Yamaguti, 1934 is a predominant parasite of cyprinid fish all over the world. This study was conducted to investigate the prevalence and mean intensity of Asian fish tapeworm (Bothriocephalus acheilognathi) in Golden Mahseer (Tor putitora) in Mahakali River, Nepal from October 2021 to September 2022. A total of 149 Tor fish were collected from the four sites of the river using gill nets and also purchased from the local markets of respective sites assuring the fish were from the Mahakali River. Parasites were recovered and processed using standard helminthological methods. Overall, prevalence and intensity of the Bothriocephalus acheilognathi in Tor putitora were 4.69% and 2.14 respectively. Size-wise, higher prevalence and intensity were found in 0.1-0.2 m long fish (5.71%, 2.5) than ˃0.2 m long fish (4%, 1.66). Weight-wise, highest prevalence was found in 0.101-0.15 kg weighted fish (8.82%) and highest intensity in 0.051-0.1 kg weighted fish (4). Month and sex-wise, highest prevalence and intensity were observed in April (17.39%, 2.5) followed by July (8.33%, 2), January (6.66%, 1) and June (5.88%, 2) in female host fish (5%, 2.14). Higher prevalence and intensity were found in spring season (10.52%, 2.5) followed by summer (4.87%, 2) and winter season (2.32%, 1). Statistically, the prevalence and intensity of the parasite were insignificant (p ˃ 0.05). This study reveals stable low infection of the Asian fish tapeworm in Golden Mahseer but increases the risk of dissemination of parasites from the Mahakali River to nearby fish farms and also zoonotic risk to human.