一例七彩山鸡异刺线虫感染的临床诊断及其分子生物学鉴定

Clinical Diagnosis of a Case of Heterakis Infection in Phasianus colchicus and Molecular Biological Identification of Pathogeny

为确诊一例七彩山鸡疑似感染寄生虫死亡的原因,使用剖检、光镜形态学检测、HE病理染色观察等方法进行了临床诊断,使用PCR技术对获得的虫体18S rRNA进行扩增,鉴定感染虫体类型。剖检发现,病禽肠道黏膜内有细长白条状的线虫体寄生,感染数量较多,肝、心等部位未见明显病变;形态学检测发现,该线虫具有较为典型的尾刺结构。结合剖检症状和形态学鉴定,初步判断病禽感染的消化道线虫为异刺线虫。病理组织学检查发现,虫体寄生的肠道黏膜出现损伤及炎性症状;分子生物学鉴定发现,该线虫18S rRNA的PCR扩增条带大小为760 bp,同源性与鸡异刺线虫(DQ503462.1)最接近。经综合诊断,判定异刺线虫感染是导致本次七彩山鸡死亡的主要原因。本次分析鉴定的虫株与家禽源异刺线虫同源性较高,表明七彩山鸡感染的异刺线虫可能来自鸡等普通家禽。这提示,散养特种禽应定期驱虫,加强禽舍卫生清扫,尽量避免与普通家禽混养。

It was reported that several Phasianus colchicus suspected of being infected with parasites died,in order to confirm the cause of death,the Phasianus colchicus were clinically diagnosed through autopsy,morphological examination by light microscope,and observation by HE pathological staining,then for the obtained worm,18 S rRNA was amplified by PCR to identify the type of parasite.It was found that,by autopsy,the intestinal mucosae of the Phasianus colchicus were infested by a large number of long white-striped nematodes,and no obvious lesions were observed in livers and hearts;it was found that,by morphological examination,the nematodes were with typical tail spines.It was preliminarily determined that what the Phasianus colchicus infected was Heterakis according to the symptoms as observed by autopsy and morphological examination.It was found that,by histopathological examination,the intestinal mucosae where worms parasitized were damaged with inflammatory symptoms;it was found that,by molecular biological identification,the amplified band of 18 S rRNA was 760 bp,its homology was closest to that of Heterorhabdus gallinarum(DQ503462.1).It was concluded that the death of the Phasianus colchicus was mainly caused by Heterakis infection.The homology of the isolates identified in the study with poultry Heterakis was closest,which indicated that the Heterakis in Phasianus colchicus might come from chicken and other common poultry.Therefore,special poultry kept in free range should be regularly dewormed,their houses should be thoroughly cleaned and any mixed feeding with common poultry should be avoided as far as possible.