Influenza A virus surveillance in domestic pigs in Kazakhstan 2018-2021

ABSTRACT: This study described the results of a surveillance program monitoring circulation of influenza A viruses among domestic pigs (Sus domesticus) in Kazakhstan during 2018-2021. PCR data derived from 2,513 samples (nasopharyngeal swabs) collected from swine on large pig complexes and peasant farms located in different regions of Kazakhstan revealed that about 5% of samples were positive for influenza A virus RNA. This result suggested low levels of influenza A virus circulation in Kazakhstan. Subtyping of a set of samples revealed that the main strains circulating in 2018-2019 were A/H1N1 and A/H3N2.Surveillance conducted in 2020-2021 identified only A/H1N1 viruses in swine. The PCR data were confirmed by isolation of six strains: five influenza A/H1N1 viruses and one A/H3N2 virus.