浙江省某鸡场火鸡组织滴虫和异刺线虫感染调查和分析OA

To investigate the prevalence of Histomonas meleagridis and Heterakis gallinarum in Zhejiang Province,an epidemiological survey was conducted on a free-range forest poultry farm in Qingtian County suspected of histomoniasis.Necropsy and gross pathological examinations were performed on diseased chickens.Fecal samples and cecal contents were collected for microscopic observation and analysis.Polymerase chain reaction(PCR)was used to amplify and sequence the 18S rRNA gene of H.meleagridis.The parasite was isolated and cultured in vitro using M199 medium,and the isolates were identified and compared with cecal content samples by PCR.Sequence homology analysis and phylogenetic tree construction were conducted based on the obtained sequences.The results showed typical"copper coin spot"like lesions on the liver surface of diseased chickens.Flagellated forms of H.meleagridis,as well as adults and eggs of H.gallinarum,were observed in feces and cecal contents.The PCR-positive rate of fecal samples was 3.4%(4/117),and specific bands of the H.meleagridis 18S rRNA gene were amplified from liver,fecal,cecal content,and parasite samples.A Qingtian isolate of H.meleagridis was successfully obtained through in vitro culture and confirmed by PCR.The 18S rRNA gene sequence of this isolate showed 99.6%homology with the AH-2 strain from Anhui and the YZ4 strain from Jiangsu,and clustered within the same subclade in the phylogenetic tree.These findings indicate a mixed infection of H.meleagridis and H.gallinarum in the investigated farm,and the infecting strains are likely local endemic strains.This study provides a reference for the prevention and control of mixed infections caused by H.meleagridis and H.gallinarum in Zhejiang Province.