Epidemiological Investigation Of Porcine Pseudorabies In Henan Province And Isolation And Determination Of Virus

Pseudorabies(PR)is an acute infectious disease caused by Pseudorabies virus(PRV).It has a wide range of hosts and can cause infection in a variety of animals,including fever,encephalomyelitis,respiration and Neurological disorders.PRV has latent infection ability.The PRV virus can be introduced into the respiratory tract through the nose and mouth of susceptible pigs in an aerosol form,and invading the central nervous system through nerve conduction eventually leads to neurological symptoms.This study systematically investigates and analyzes the current wild-type infection of PR in Henan,and understands the epidemic situation.It also identifies the pseudorabies virus for genetic evolution analysis to understand the changes of pseudorabies virus and pseudorabies.Prevention and eradication are important.1.Analysis of antibodies against wild rabies virus infection in some farms in Henan ProvinceIn order to investigate the wild-type infection of pseudorabies in Henan and to understand the prevalence of the disease,8947 pig sera from 387 farms in the whole year of 2018 were tested with the PRV wild-type antibody test kit and collected.The data of wild-type antibody detection in the animal disease detection and diagnosis center of Henan Agricultural University in the past three years.The results showed that the positive rate of pig farms in Henan was 86.3%,and the seroprevalence rate was 41.53%.The positive rate of piglets in the delivery room was 65.5%,and the positive rate of gilts was 21.1%.The seroprevalence rates for 2016-2018 were 47.8%,44.1%,and 41.43%,respectively.It can be seen that the PRV wild-type infection in Henan is very serious,and there are more positive pig farms,but the overall seroprevalence rate is decreasing year by year.2.Isolation and Identification of Porcine Pseudorabies VirusDuring the period from October 2017 to December 2018,the suspected pseudorabies disease was inoculated into Vero cells for virus isolation.Typical PRV lesions such as cell rounding,contraction and syncytia production occurred 48 hours after exposure.Identification by PCR identification,neutralization test,animal experiment,and the like.The TCID50 of the four isolates was detected as 10-6.8/0.1 ml,10-7.0/0.1 ml,10-7.1/0.1 ml,10-7.3/0.1 ml,respectively,and all four strains were able to be subjected to standard PRV.Positive sera were specifically neutralized,and the 4 strains isolated were identified as PRV strains.3.Sequence analysis of gC,gD and gE genes of four strains isolated from PRVAccording to the PRV gene sequence in GenBank,the whole gene-specific primers of gE gene,gC gene and gD gene were designed,and the DNA of 4 strains of PRV isolates was used as a template for PCR amplification and sequencing.The DNAStar software was used to analyze the sequence of the strain with the reference strains at home and abroad,to analyze the similarity of nucleotide sequence and amino acid sequence,and to analyze the genetic evolution tree of amino acid sequence.The results showed that the nucleotide and amino acid similarity between the gE gene and the reference strain were 97.7%-100%and 95.7%and 100%,respectively.The similarity between the gC gene sequence and the reference strain nucleotide and amino acid was 95.9%-100%and 93.1%and 100%,the nucleotide and amino acid similarity of the gD gene is 98.8%-99.3%and 97.5%-99.8%,respectively.All the four isolates were closely related to the domestic strains HN1201 and JS-2012.