The Florida dolphin, a juvenile male, was found in a canal in Dixie County in March, where residents noticed the animal was trapped between the piers of a pier and a seawall, Dr. Michael Walsh, a veterinarian at the University of Florida College of Veterinary Medicine who directs the university’s marine animal rescue program.
When rescuers arrived, the dolphin was already dead, he said. The team, which routinely performs autopsies, collected a variety of samples from the dolphin and stored them until they could be analyzed more closely.
At the time, scientists had no reason to believe avian flu had entered dolphins, and they were in no particular hurry, said Dr. Walsh, who was examining with Dr. Robert Ossiboff, a veterinary pathologist. and Andrew Allison, a veterinary virologist, both at the University of Florida College of Veterinary Medicine.
When the results came back this summer, they showed signs of inflammation in the dolphin’s brain and surrounding tissues, said Dr. Walsh. Scientists have previously documented brain inflammation in fox pups infected with the virus, which can cause neurological symptoms in birds and mammals.
Subsequent laboratory tests revealed Eurasian H5N1 in the dolphin’s brain and lungs. “The brain tissue showed really high levels of virus,” said Dr. Walsh.
Whether the virus contributed to the dolphin’s death remains unknown, as does exactly how the animal contracted it. But it’s not hard to imagine a young dolphin examining a sick bird near shore, said Dr. Walsh, adding, “These animals are always curious about their surroundings and checking things out. So if he comes across a sick, either dying or dead bird, he might be very curious about it. He could say it.”