Influenza virus is an infectious agent belonging to the virus family Orthomyxoviridae that causes a respiratory tract infection (influenza or 'flu') in vertebrates. There are three main species ...

Outbreaks of influenza D virus (IDV) continue to be reported in many countries. On the basis of the hemagglutinin-esterase fusion (HEF) gene, five IDV genetic lineages have been identified: D/OK, ...