Definitive Host Fish and Their Geographical Distribution of the Asian Fish Tapeworm,Bothriocephalus acheilognathi,in China

The Asian Fish Tapeworm( Bothriocephalus acheilognathi Yamaguti,1934)( Cestoda:Bothriocephalidea) is an important parasite of cultured carp,which has caused worldwide concern,due to its pathogenecity and wide distribution.It was commonly considered to be originated from East Asian,however,reports on its infected host range and distribution in China was limited.Based on authors field investigation and the previous records in literatures,this paper firstly present the detailed host range and distribution of B.acheilognathi in China.In the present research,tapeworms found were isolated from the host's intestine and rinsed in saline solution.Specimens used for morphological identification were fixed with hot( almost boiling)4% formaldehyde solution,and permanent preparations were stained with iron hydrochloric carmine,destained in 70% acid ethanol,dehydrated in an alcohol series,cleared in clove oil and mounted in Canada balsam.The result revealed that B.acheilognathi occurred in almost all freshwater habitats from north to south China( LiaoheRiver,Haihe River,IrtySh River,Yili River,Yellow River,Huaihe River,Yangtze River,Min River,Pearl River),infected about 31 freshwater fishes,including 26 from Cyprinidae,1 from Channidae,1 from Eleotridae,1 from Cichlidae and 2 from Poeciliidae.B.acheilognathi from wild fish Opsariichthys bidens and Squaliobarbus curriculus habiting in all Rivers present higher infection prevalence.Based on the epidemiologic characters and the population genetic variations,authors considered that fish O.bidens maybe the primary hosts of B.acheilognathi.As the wide geographic distribution and diverse host,B.acheilognathi represents an attractive model for studies on parasite host switch and speciation.Future research is required to enclose the genetic diversity of B.acheilognathi populations from different definitive hosts.