The only other known case of rabies in a sea mammal was in a ringed seal in Norway's Svalbard islands in the early 1980s. That seal had likely been infected by a rabid arctic fox, researchers said, and there was no evidence of rabies spreading among seals there.

Scientists in South Africa have identified an outbreak of rabies in Cape fur seals, marking the first time the virus has spread among sea mammals. The virus is believed to have been transmitted from jackals in Namibia.