Influenza D virus

Influenza D virus is a species in the virus genus Deltainfluenzavirus, in the family Orthomyxoviridae, that causes influenza.

Influenza D viruses are known to infect pigs and cattle; no human infections from this virus have been observed. First isolated from pigs in 2011, the virus was categorized as a new genus of Orthomyxoviridae in 2016, distinct from the previously-known Influenzavirus C genus; before then, Influenza D virus was thought to be a subtype of Influenzavirus C.

Cases of infections from the Type D virus are rare compared to Types A, B, and C. Similar to Type C, Type D has 7 RNA segments and encodes 9 proteins, while Types A and B have 8 RNA segments and encode at least 10 proteins.