摘要
[Objective]The paper was to identify,isolate,and characterize porcine astrovirus in Shandong Province between 2021 and 2023.[Method]A total of 1025 samples of porcine diarrhea samples were collected from various regions of Shandong Province between January 2021 and October 2023.The samples were tested by RT-PCR,followed by sequencing and phylogenetic analyses of the polymerase.[Result]The total positive rate of PAstV was 34.6%(355/1025).The respective proportions of individuals infected with PAstV-1,PAstV-2,PAstV-4 and PAstV-5 were 25.4%(90/355),28.2%(100/355),35.2%(125/355)and 22.5%(80/355),respectively.Additionally,mixed infection was observed.Meanwhile,849 samples of healthy pigs were tested by RT-PCR,and the results demonstrated that the total positive rate of PAstV was 8.13%(69/849).Of these,the proportion of PAstV-1,PAstV-2 and PAstV-4 infection was 27.5%(19/69),37.7%(26/69)and 40.6%(28/69),and a mixed infection also existed.Further sequencing and characterization of some the selected isolates revealed low sequence identities(56.2%)with known PAstV strains,indicating the presence of novel types or genotypes of PAstVs.Furthermore,the isolation conditions of porcine astrovirus were optimized,resulting in the purification of a pure PAstV-4 strain(designated PAstV-4-GRF1).The virus was found to exhibit typical astroviral morphology,with nucleotide identity ranging from 89.9 to 95.4%with previously published PAstV-4 strains.Then,macrovirus transcriptome sequencing showed that 88.30%of the CRF1 samples were mammalian astroviruses.By species classification,PAstV 4 and PAstV 2 accounted for 21.79%and 0.32%,respectively.Phylogenetic tree analysis showed that the c15050 fragment was identical to the GRF-1 sequencing fragment of the isolated strain,and exhibited the highest homology with the Hunan PAstV-4 sequence MK460231 in China.[Conclusion]As the inaugural isolated PAstV-4 strain,it furnishes pivotal materialfor the investigation ofthe biological and pathogenic properties of this virus as well as for the prospectivedevelopment of relevant biological and diagnostic reagents.
基金
Supported by Sub-project of the National Key Research and Development Program(2023YFD1800804-06)
National Natural Science Funds of China(32302918 and 32302919)
Innovation Capacity Improvement Project for Technology-based SMEs in Shandong Province(2023TSGC0006)
Science and Technology Cooperation Project of Shandong and Chongqing(2022LYXZ030)
Shandong Province Key R&D Program Rural Revitalization Project(2023TZXD083)。
