猪流行性腹泻病毒流行病学调查及毒株致病力研究

Epidemiological Investigation and Virulence of Porcine Epidemic Diarrhea Virus

为掌握我国PEDV流行情况,在2020年8月至2023年5月期间,共收集160个场区、908份临床腹泻样品,采用qPCR方法进行PEDV抗原检测,并选取部分病料进行了S基因序列测定和分析,同时分离获得了两株GⅡ群流行毒株,并对其致病力进行了研究。结果显示:PEDV病料阳性率为50.7%(460/908),猪场阳性率为68.8%(110/160)。可见,在临床出现腹泻症状的猪中,有很大部分是由PEDV引起的;对S基因的分析显示,当前我国流行的PEDV主要为GⅡ群,占比为90.3%(65/72),而GⅠ群呈现零星发病,占比为9.7%(7/72);成功分离获得两株GⅡ群流行毒株,两者均对3~4月龄的育肥猪有致病力,口服后,33%~67%猪可出现腹泻,实验猪100%感染并持续排毒,最长排毒时间可达攻毒后13 d。对PEDV的流行病学、基因变异和致病力进行的研究为疫病防控和产品开发提供了依据。

In order to grasp the prevalence of PEDV in China,a total of 908 clinical diarrhea samples from 160 sites were collected from August 2020 to May 2023,and PEDV antigen detection was performed by qPCR.Some samples were selected for S gene sequencing and analysis,and two prevalent strains of group GⅡwere isolated.The pathogenicity of these two strains was also studied.The results showed that the positive rate of PEDV was 50.7%(460/908)in disease samples and 68.8%(110/160)in pig farms,indicating that a large part of pigs with clinical diarrhea symptoms were caused by PEDV.The analysis of S gene showed that the current prevalence of PEDV in China was mainly in group GⅡ,accounting for 90.3%(65/72),while group GⅠshowed sporadic incidence,accounting for 9.7%(7/72).Two viral strains of Group GⅡwere successfully isolated and obtained,both of which had pathogenicity to fattening pigs of 3-4 months of age.The experimental pigs were attacked orally,33%-67%of the pigs could have diarrhea,100%of the experimental pigs were infected and sustained detoxification,and the longest detoxification time could reach 13 days after the challenge.The epidemiology,genetic variation and pathogenicity of PEDV were studied in this study,which provided a basis for disease prevention and control and product development.