Genetic Characterization of H5N1 Influenza A Virus Isolated from Pigs in Ogbomoso, Nigeria

Oladipo E.K.*1,2, Adeniji J.A.3, Oloke J.K2

1Department of Microbiology, Laboratory of Molecular Biology and Bioinformatics, Adeleke University, Ede, Osun State, Nigeria; 2Department of Pure and Applied Biology (Microbiology / Virology Unit), Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria; 3Department of Virology, College of Medicine, University of Ibadan, Ibadan, Oyo State, Nigeria

Introduction: Pigs are susceptible to infections with both avian and mammalian Influenza A viruses. Pigs play an important role in the ecology of influenza virus. The changing epidemiology of influenza has a significant implications for the circulation of viruses in pigs. Little is known about the circulating strains in this area. To understand the current the current situation regarding influenza viruses circulating among pigs in Ogbomoso, a surveillance study was conducted.

Methods: Viral isolation from nasal swabs collected from one hundred pigs was performed using egg inoculation, MDCK and haemagglutination assay. Reverse transcriptase polymerase chain reaction (RT-PCR) was carried out by amplifying the matrix gene for identification. The sequence was determined by Sanger dideoxy sequencing. The homology analysis was implemented by Influenza Research database (IRD) and phylogenetic analysis was performed by Maximum – Likelihood methods using MEGA 7.10 software package.

Results: Multiple sequence alignment showed that the matrix (M) genes of A/H5N1/Ogbomoso/2014 influenza virus showed highest nucleotide identity with A/Pigeon/Sichuan/NCXN29/2014(H5N1) and A/Duck/Sichuan/NCXN11/2014 (H5N1) {98% and 97% respectively}. The phylogenetic analysis of the matrix gene of A/H5N1/Ogbomoso/2014 indicated that this virus is closely related to H5N1 strains circulating in southwest China.

Conclusion: This is the first report of genetic characterization of influenza A virus H5N1 of swine origin isolate from Ogbomoso. The presented results can further promote Influenza A virus surveillance and epidemiology insight in this community. The potential role of pigs in interspecies transmission remains important.

Keywords: Pigs, H5N1, Ogbomoso, Influenza A, Genetic Characterization.