Summary
Influenza D virus (IDV) is mainly associated with respiratory disease in cattle and its possible involvement in the bovine respiratory disease complex (BRDC). Despite its global distribution, uncertainties remain regarding the epidemiology and ecological behavior of the virus, its spread and transmission mechanisms between and within animal species, its potential for transmission to humans, and the associated public health risk in the context of an emerging pathogen. Due to its relatively recent discovery, IDV is the least studied of the influenza viruses. Therefore, this review presents basic information on virion structure, phylogenetic analysis of circulating strains, molecular characteristics, clinical signs, and diagnostic methods.