| Wood frog is a kind of amphibian with important economic value,as a usual protected animal,it has been banned from illegal capture and utilization.Therefore,artificial breeding has become an important way for its increment and utilization.However,some diseases of wood frog breeding have a great impact on the aquaculture.Parasitic disease is one of the most important diseases,especially trematodes infection has become an important factor affecting frog breeding.There are a lot of studies on trematodes of wood frogs,and more than 60 species of flukes belonged to 24 genera 12 families have been reported in China,However,there is no detailed report on trematodes in wood frog in China.From September 2019 to December 2020,a total of 1376 wood frogs were collected in 19 locations from 13 cities in Heilongjiang Province,including 1150 Rana amurensis and 226 Rana dybowskii.The adult flukes in lung,bladder and intestine and metacercariae in muscle were collected by autopsy.The adult flukes and metacercariae were identified by preliminary morphological identification,then the molecular biology was used for further identified by the ITS and 28 S ribosomal sequence.The obtained sequences were analysed and conducted evolutionary analysis.Finally,the situation of wood frogs infected with trematodes was statistically analysed.In results,a number of metacercariae and 1912 flukes were detected,which were identified as eight species of flukes(six kinds adult flukes and two kinds metacercariae)in seven families and seven genera.They are Haematoloechus variegatus,Glypthelmins quieta,Diplodiscus japonicus,Diplodiscus mehari,Gorgodera dunhua,Pleurogenoides sp.,Pharyngostomum sp.and Apharyngostrigea sp.The adult flukes parasitize in lung,intestine and bladder,and the metacercaria were found in leg muscles and intestinal wall muscles.Among them,H.variegatus,G.quiet,Pharyngostomum sp.and Apharyngostrigea sp.were found for the first time in frog in China.The results showed that the infection rate of wood frog was 35.9% in totally,the fluke infection rates of R.amurensis and R.dybowskii were 36% and 35.84%,respectively.The maximum infection intensity was 83.Statistical analysis showed that the infection rate of wood frog infected with trematodes was different in different places with significant difference(P<0.001).The highest infection rate was 62.5% in Shuangyashan,and there was no trematode detected in Nehe City,Heilongjiang Province.Body weight was an important factor affecting the infection of wood frog trematode,and there were a very significant difference(P<0.001)and significant difference among different body weights(P<0.05)in R.amurensis and R.dybowskii,respectively.But there was no difference between different species and sexes.Most wood frogs infected with trematodes were mixed infection,and even up to four species of trematodes were infected by one frog,which mainly infected D.japonicus and D.mehari.D.japonicus and D.mehari were lived in two species of wood frog.They could be detected in all areas expect Nehe city and the infection rates are 26.6% and 13.15%,respectively.Therefore,these two species flukes are the dominant species of wood frogs.The present study was the investigation about the infection of wood frogs in Heilongjiang Province for the first time.There are six kinds of adult flukes and two kinds of metacercaria were detected in totally,of which two species of flukes and two metacercariae were found for the first time in China.D.japonicus and D.mehari are two dominant species of wood frogs in Heilongjiang Province.This study provides a basis for the prevention and control of fluke disease of wood frog breeding in Heilongjiang Province. |
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