Molecular Virological Investigation Of Calf Diarrhea And P Reliminary Analysis Of Calf Fecal Viral Metagenomics In Ningxia

Calf diarrhea is a digestive tract disease in calves.Under the influence of many factors,calves have clinical features such as dyspepsia,diarrhea,dehydration,and emaciation,and severe and persistent diarrhea will lead to growth retardation,delayed first calving,low milk yield,and even death of calves.It is a common and frequently-occurring disease in the calf breeding industry and one of the main causes of economic losses in cattle farms.Calf diarrhea is divided into infectious diarrhea and noninfectious diarrhea,Infectious diarrhea is caused by pathogenic microorganisms such as viruses,bacteria,and parasites,and non-infectious diarrhea is mostly caused by nutrition,stress,and environmental sanitation.Common diarrhea viruses include Bovine viral diarrhea virus(BVDV),Bovine rotavirus(BRV),Bovine coronavirus(BCoV),emerging viruses include Bovine astrovirus(BAstV),Bovine torovirus(BToV),Bovine kobuvirus(BKoV),Bovine parvovirus(BPV)and Bovine norovirus(BNoV)have also been gradually concerned.In order to rapidly detect the infection of BVDV,BRV,BCoV,BAstV,BToV and BKoV,primers were designed for the conserved regions of the six viruses,and a multiplex PCR assay for the simultaneous detection of the six viruses was established,which has good specificity and sensitivity and can be used to detect clinical samples.To specifically understand the epidemiological status of viral diarrhea in calves,molecular biological detection of BVDV,BRV,BCoV,BAstV,BToV,BKoV,BNoV and BPV in calf feces was performed by constructing a multiplex PCR and using the reference PCR method.The results showed that the detection rates of BRV,BCoV,BAstV,BToV,BKoV,BNoV,and BPV in calf feces in Ningxia were 14.23%,5.69%,14.23%,10.57%,26.02%,4.47%,and 2.44%,respectively.The infection of diarrhea virus presents complexity and diversity.Genetic evolution analysis showed that the nucleic acid sequences of the positive samples were highly consistent and were on the branch of the virus group,further indicating that BRV-A,BCoV,BAstV,BToV,BKoV,BNoV GⅢ.2 and BPV1 were circulating in the calf population in Ningxia.In order to understand the viral composition in the feces of calves in Ningxia,feces were collected from calves less than 6 months of age,and three pooled samples from the healthy and three diarrhea groups were detected using viral metagenomics techniques,respectively.The sequencing results were annotated to 26 viridae including Picornaviridae,Astroviridae,Picobirnaviridae,Caliciviridae,Tobaniviridae,Reoviridae,and Coronaviridae.The genera annotated as Calf Diarrhea Virus are Bopivirus,Enterovirus,Kobuvirus,Hunnivirus,Nebovirus,Norovirus,Picobirnavirus,Mamastrovirus,Rotavirus,Torovirus,Betacoronavirus,Pestivirus.The results showed that the viral composition in the feces of calves in Ningxia was complex and diverse.This study analyzed the virus composition in calf feces in Ningxia,mastered the molecular prevalence of viral diarrhea,and laid the foundation for the study of emerging viruses,provided a reference for the etiological diagnosis of calf viral diarrhea,and provided data support for the prevention and control of calf diarrhea.