Pathological observation and pathogen identification of Mongolian horses infection with horse stomach fly maggots
In order to clarify the pathological changes of tissues infected with horse stomach fly maggots and the species of horse stomach flies infected,nine Mongolian horses infected horse stomach fly maggots were collected from each of the slaughterhouses in Helin and Hulunbeier,Inner Mongolia,in December 2021.Pathological observations were made on pharynx,stomach,and duodenum of the infected horses,and morphological observations were made on the third instar larvae of the stomach fly using light microscope and scanning electron microscope.And the larvae of third instar of the horse stomach fly were selected at the same time.The mitochondrial cytochrome oxidase subunit Ⅱ(COXⅡ)gene was am-plified by PCR.The phylogenetic tree was constructed by comparing the homologous sequences of the COXⅡ gene with those of other species of the Gasterophilidae in the GenBank database using MEGA 6.0,Clustal W software.The results showed that the pathological changes in the affected horses mainly con-sisted of different degrees of damage and proliferative inflammation in the pharyngeal,gastric,and duodenal mucosa,with edema of the mucosal layer,infiltration of inflammatory cells,and vacuolization of epithelial cells.There were granulomas formed in the pharynx,and inflammatory focis of parasitic lesions of maggots in the stomach.The characteristics of oral cristae and papillary sensilla of the third instar larvae of the Helin Mongolian horse stomach fly were consistent with the morphology of the third instar larvae of Gasterophilus pecorum.The third instar larvae of Hulunbeier Mongolian horse stomach fly had similar oral spine and spine characteristics to those of Gasterophilus intestinalis.The phylogenetic tree indicated that Helin Mongolian horse stomach fly clustered with G.pecorum from the GenBank database,whereas Hulunbeier Mongolian horse stomach fly was alone in a single branch,with a large genetic distance from the other stomach fly genus.Therefore,Helin Mongolian horse stomach fly was identified as G.pecorum,and Hulunbeier Mongolian horse stomach fly was a genetically more variable stomach fly variant.
国家科技期刊平台
NSTL
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