swine flu, conceptual composite 3d . influenza virus h3n2 and portrait of a pig

virus pig swine flu influenza molecular structure infectious virology spike pathology microscopic immune contagious hemagglutinin orthomyxoviridae epidemic glycosylation cold orthomyxovirus glycan cell human microscope headache h3n2 3d illustration health research infection pandemic avian response vaccine concept biology microbiology diagnosis glycosylated science illness disease molecule medical 2022 2023 portrait isolated plain background