Epidemiological Survey Of Swine Influenza Virus H1N1and H3N2in Swine Herd In Nanjing

Swine influenza caused by the Orthomyxoviridae family influenza A virus is a kind of pigs’acute and highly contagious respiratory infections, which greatly do harm to the global livestock industry and human public health. There are nine different subtypes of Swine influenza virus, and SIV H1N1and H3N2is mainly epidemic in China.Mainly based on the SIV H1N1and H3N2, epidemiological survey was conducted in nine counties of Nanjing. Pig blood samples and swine nasal swabs were collected for testing, and the samples covered the circulation and breeding link, and other fields. The survey was conducted for a year-long from serology and etiology, including different days age and different species of pigs. The investigation results in this study reflect the prevalent situation of the SIV H1N1and H3N2.Hemagglutination inhibition test results show, the positive rates of SIV H1N1and H3N2antibody were3.64%and13.04%, respectively, from a total of989samples. The survey results from different seasons found that positive rate of the SIV H1N1and H3N2antibody was6.31%and17.57%respectively, which was higher in spring. From the results of different counties, we can find, the positive rate of SIV H1N1antibodies was higher in Yuhua District by8.57%, and the positive rate of SIV H3N2antibody was higher by34.88%in Jianye District, while the two subtypes antibodies of SIV was not detected in Xuanwu District. It shows that there are some regional differences in the distribution of the SIV H1N1and H3N2antibody. The results of antibody analysis showed that, with the pigs’ age increasing, the positive rate of the two subtypes SIV antibodies will also increase accordingly. Some samples were tested using the ELISA method, and the results were in agreement basically with the results of the hemagglutination inhibition assay.According to the SIV gene sequences, using Primer premier5.0, the specific primers of SIV H1N1and H3N2were designed, and the samples were detected by RT-PCR method. The results showed that, the SIV H1N1and H3N2was not detected from the pigs.Serological survey reflects the actual situation of the SIV H1N1and H3N2antibody in Nanjing. Overall, the antibody positive rate of the two subtypes is not high. The etiological survey showed that two subtypes of SIV were possibility infected in a certain period in pigs of Nanjing, and heal quickly, therefore two subtypes of SIV were not detected.