Epidemiological Investigation Of Pseudorabies And Genetic Variation Analysis Of PRV-gE Genes In Some Pigs Farms In Anhui Province

Pseudorabies(Pseudorabies Disease),also known as Aujeszky’S disease(Aujeszky’S,AD),is an acute,highly contagious disease caused by pseudorabies virus(pseudorabies virus.PRV),which can infect various animals.Swine is the natural reservoir host,the clinical symptoms arc sow abortion,stillbirth,mummified fetus and piglet neurosis.At present,the disease is prevalent in some areas of China,and seriously endangers the healthy development of pig industry.Since the widespread application of Bartha-K61 vaccine since the 1990 s,the epidemic situation of PR has been effectively controlled.However,since the second half of2011,the occurrence of PR was continuously reported in pig farms with immune vaccine.Some scholars have shown that the antigenicity of the isolated strains have obvious variation compared with the traditional strains.The antibodies induced by the traditional PRV vaccine can not effectively neutralize the newly isolated virus strains,and thus can not protect the pigs completely.Since then,more and more reports about PRV variant strains have been reported,and researchs on them have gradually become a hot topic.From the laboratory received 526 samples of pathogen detection and 6639 samples of serum detection from farms in different regions of Anhui province.The test results showed that the nucleic acid positive rate of PRV was 11.60%(61 of 526),which was lower than the PR positive rate of Anhui province reported in previous years,indicating the prevention and control measures of PR in Anhui province have been slightly effective in the past two years,and local farms pay more attention to the prevention and control of PR and scientific pig breeding.The results of serological detection showed that the positive rate of antibody against g E and g B was26.16% and 90.10% respectively.The test of antibody against g E showed that there still exist wild virus infection in pig farms in Anhui province,while the test results of antibody against g B showed that the vaccination coverage rate of PRV in pig farms from Anhui province was ideal in relative terms.GE gene amplification,cloning and genetic evolution analysis were performed on 6 of the61 positive tissue samples.The results showed that the g E gene nucleotide sequence homology of the 6 strains of PRV isolates was 99.2%～99.9%,Belonged to the pseudorabies Group 1gene Group.the strains isolated from this study had high homology with domestic strains and belonged to the same branch in genetic evolution,which was significantly different from European and American reference strains.Therefore,we can conclude that there are several characteristics of pseudorabies in Anhui: 1 widespread in large-scale pig farms and high infection rate;2 isolated strains have higher homology with domestic strains.Therefore,the construction of a new gene deleted mutant vaccine and the development of bivalent or polyvalent vaccine will be the main direction of the future development for the PRV vaccine.