Novel poxvirus discovered in sea otters

Published on July 16, 2014
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A study of unusual skin lesions on two orphaned sea otter pups by University of Florida scientists and their collaborators has led to the identification of a previously unknown poxvirus.

“To our knowledge, this is the first report of a poxvirus in a mustelid, the group of mammals including otters, mink, badgers, and related species,” said Dr. James Wellehan, an assistant professor at the UF College of Veterinary Medicine who specializes in virology and zoological medicine.

Sea otter and pup
A wild southern female sea otter and her pup sheltering in the Great Tide Pool at the Monterey Bay Aquarium (Courtesy of Monterey Bay Aquarium/Photo by Tyson V. Rininger)

DNA testing revealed that viral gene sequences from both otters were identical and that this represents a virus that has never before been identified, according to findings published online this May by the Journal of Wildlife Diseases.

Scientists say the potential for transmission of this particular poxvirus to humans is unclear. Although no poxvirus infections have been reported in humans exposed to sea otters, the scientists advise wearing protective clothes and gloves when handling these animals, either in the wild or in rehabilitation settings.

The otter pups came from two geographically and genetically distinct populations—Alaska and California—leading researchers to conclude the virus must be geographically widespread. Both otters were undergoing rehabilitation at the time the skin lesions were detected and subsequently tested.

UF researchers found the virus poses a threat to otters because the lesions it causes interfere with the animals’ hair coat, impeding their natural ability to survive in water.

“When you look at a Steller’s sea cow, which is now extinct, a whale or a seal, they all have significant blubber layers,” Dr. Wellehan said. “But what keeps sea otters alive in the cold water is their hair coat. Anything affecting their hair coat, with its incredible density of fur, is a huge problem for them.”

Additional studies are needed to determine the source of the virus, how it was transmitted to the otters, its zoonotic potential, and its biological importance. “Understanding the diversity, ecology, and evolution of medically important groups of viruses is crucial to prediction and monitoring,” Dr. Wellehan said.

Other collaborators on the research team were Dr. Thomas B. Waltzek, an assistant professor of infectious diseases and co-director of UF’s Aquatic Animal Health program, and Alaska SeaLife Center, Monterey Bay Aquarium, Northwest ZooPath, and the Canadian Department of Fisheries and Oceans.