Topic summary
Influenza D virus
Influenza D virus is a species in the virusgenusDeltainfluenzavirus, 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 Influenza C virus.
Cases of infections from the Type D virus are rare compared to Types A, B, and C. Similar to Type C, Type D has seven RNA segments and encodes nine proteins, while Types A and B have eight RNA segments and encode at least 10 proteins.