An influenza D virus in D/Yama2019 lineage from stillbirth fetus of cattle in China

Influenza D virus (IDV), a respiratory pathogen primarily affecting cattle, is known to have the potential to infect a wide range of animal species. In this study, a novel IDV strain, designated D/JLSL and belonging to the D/Yama2019 lineage, was isolated from a stillborn bovine fetus. Phylogenetic analysis revealed that all 7 genomic segments of the D/JLSL cluster within the D/Yama2019 lineage. Notably, the hemagglutinin-esterase-fusion (HEF) protein of D/JLSL exhibits 7 amino acid substitutions compared with the 3 previously characterized D/Yama2019 strains. These findings suggest that D/JLSL may represent a distinct variant within the D/Yama2019 lineage. This study marks the first identification and genetic characterization of IDV from the D/Yama2019 lineage in a stillborn bovine fetus, highlighting the need for further surveillance to elucidate its prevalence and biological properties.