Epidemiologic Investigation Of Porcine Pseudorabies In Henan Province From 2017 To 2018

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 are 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.In order to discover the epidemic situation of swine pseudorabies in Henan Province,and provide reference for scientific prevention and control of pseudorabies,the serum epidemiology,pathogen epidemiology and gE gene genetic variation of the disease were carried out.14508 serum samples from 240 pig farms of Henan Provincein in 2017-2018 were detected on PRV gE antibody by enzyme-linked immunosorbent assay(ELISA),the result showed that:3995 samples from 118 farms were detected as positive,the total positive rate in herd and indivadual were 49.17%and 27.54%respectively;the positive rate of herd(82.14%)and indivadual(53.43%)were both highest in eastern Henan,then the central Henan and Northern Henan,and the positive rate of herd(30%)and indivadual(14.7%)were the lowest in southern Henan;The indivadual positive rate of fattening pigs,nursery pigs and sows were higher(39.47%,28.34%and 26.97%),the indivadual positive rates of boar,piglet and reserve sows were lower(20.06%,21.34%and 22.87%);PRV wild virus infection in winter and spring is more serious.A total of 2856 tissue samples from commercial pig farms,slaughtehouses and harmless treatment plants of carcass in Henan province were tested by fluorescence PCR,and 41 positive samples were detected,with a positive detection rate of 1.44%.The detection rate of the harmless treatment plants is the highest,which is 3.57%.The detection rate of the commercial pig farms and the slaughterhousesis almost the same,which is 0.54%and 0.57%respectively.GE gene amplification,cloning and genetic evolution analysis were performed on 6 of the 41 positive tissue samples.The results showed that the gE gene nucleotide sequence homology of the 6 strains of PRV isolates was 99.1%?99.9%,belonged to the pseudorabies Group 1 gene Group.The nucleotide homology with Min-A strain was 98.4%?99%,and the nucleotide homology with HNBA2012-CH strain prevalent in China after 2012 was 99.2%?99.8%.The nucleotide homology with foreign isolates BecKer-USA-2002,89V87-Belgium-2009,and 75V19-belgium-2009 was 96.9%?97.8%,not belonging to the same gene group.Nucleotide sequence analysis showed that the isolated strains had individual site mutations compared with the Min-A nucleotide sequence of the PRV standard strain.Therefore,the gE gene of Henan province's popular PRV strain during 2017-2018 was significantly different from that of the classical strain,and it has higher homology with other currently popular domestic strains,belonging to the same branch.