Short communicationThe genome of an influenza virus from a pilot whale: Relation to influenza viruses of gulls and marine mammals

- The first full genome of a cetacean influenza virus (from a pilot whale) is presented.
- Sequence data reveal a transspecies infection of the diseased pilot whale.
- This virus is characteristic of gulls and terns of the western hemisphere.
- This virus exhibits a rare H13N2 genotype and may have ceased in the 1980s.
- Virus isolates of a baleen whale and pinnipeds are characteristic of geese and ducks.

Influenza virus A/whale/Maine/328B/1984 (H13N2) was isolated from a diseased pilot whale. Since only a partial sequence was available, its complete genome was sequenced and compared to the sequences of subtype H13 influenza viruses from shorebirds and various influenza viruses of marine mammals. The data reveal a rare genotype constellation with all gene segments derived of an influenza virus adapted to gulls, terns and waders. In contrast, the phylogenetic trees indicate that the majority of influenza viruses isolated from marine mammals derived from influenza viruses adapted to geese and ducks. We conclude that A/whale/Maine/328B/1984 is the first record of an infection of a marine mammal from a gull-origin influenza virus.