Cocirculation of Two Distinct Genetic and Antigenic Lineages of Proposed Influenza D Virus in Cattle

Abstract

A novel bovine influenza virus was recently identified. Detailed genetic and antigenic studies led to the proposal that this virus represents a new genus of influenza, influenzavirus D (IDV). Here, we show that IDV is common in clinical samples of bovine respiratory disease complex (BRDC), with a prevalence similar to that of other established BRDC etiological agents. These results are in good agreement with the near-ubiquitous seroprevalence of IDV previously found. Phylogenetic analysis of complete genome sequences found evidence for two distinct cocirculating lineages of IDV which freely reassort. Significant antigenic differences, which generally agreed with the surface glycoprotein hemagglutinin esterase phylogeny, were observed between the two lineages. Based on these results, and on the ability of IDV to infect and transmit in multiple mammalian species, additional studies to determine the pathogenic potential of IDV are warranted.