Serological Investigation Of Three Subtypes Of Swine Influenza In Shandong Province

Swine influenza,or Swine Influenza(SI),is an acute,hot and highly contagious respiratory infection of swine caused by Swine influenza virus(SIV)infection.Swine flu is a zoonotic disease,and the pig's upper respiratory tract contains both human and bird flu virus receptors.If both human and bird flu viruses infect pigs,the two influenza viruses are likely to occur in pigs.Gene reassortment creates new strains of virus,and the population is often not immune to reassortant new viruses,potentially leading to an influenza pandemic.Therefore,it is of great public health importance to investigate the prevalence of swine influenza in pigs.So far,pigs in Shandong Province have not been immunized with swine influenza vaccines,so serological monitoring results can basically reflect the true antibody level of SIV infection in pigs in Shandong Province.To understand the infection status of H1 subtype and H3 subtype swine influenza virus among pig populations in Shandong Province during2016-2017,using HI antibody detection method,using poultry-type pig H1N1(EA H1N1)antigen,2009 A-type H1N1(2009)/H1N1)antigen and H3N2 subtype SIV antigen,detected7000 serums collected in Shandong Province from June 2016 to December 2017.The results showed that the total positive rate of SIV antibodies detected was 63.79%,among which birds were The positive rate of swine H1N1(EA H1N1)antibody was 56.31%.The positive rate of2009 H1N1(2009/H1N1)antibody was 24.61%,and the positive rate of H3N2 antibody was1.61%.The test results in the second half of 2016 showed that the positive rate of H1N1(EA H1N1)antibody was 45.85% in poultry-type pigs,16.20% in 2009 AH1N1(2009/H1N1)antibody,and 0.65% in H3N2 subtype antibody;The annual test results showed that the positive rate of H1N1(EA H1N1)antibody was 60.52%,the H1N1(2009/H1N1)antibody positive rate was 26.78%,and the H3N2 subtype antibody positive rate was 2.00%.The results show that in the past two years,the swine flu epidemic in Shandong province has beendominated by poultry-type pig H1N1(EA H1N1),followed by 2009 A-type H1N1(2009/H1N1).The prevalence of H3N2 subtype SIV in Shandong Province is very low..In addition,the results of the 2017 and 2016 tests showed that the positive rates of the three swine flu antibodies were significantly higher.The results of this study show that in the past two years,the positive rate of H1N1 antibody was highest in poultry-type pigs in Shandong Province,followed by 2009 A-type H1N1,and the positive rate of H3N2 antibody was relatively low;the poultry-type H1N1 and2009 A-type H1N1 antibodies were the most positive;In 2016,the positive rate of swine flu virus antibody increased,and the increase in H1N1 was most obvious.It indicates that the epidemic of three swine flu pathogens in Shandong Province has been strengthened and the pressure of prevention and control has increased.