September 2008

Barely a Scratch

Skipping invasive tests, veterinary detective work led to one happy polar bear

By Jacqueline Mitchell

Thanks to advances in medical technology, veterinarians can make diagnoses faster than ever. A blood test can reveal a toxin, or an X-ray can show exactly where it hurts. But what if an animal's size and strength makes these tests impractical?

A contented Kenda chills out at the EcoTarium, with some help from her veterinary friends. Photo: Worcester Telegram & Gazette

That's the case for Kenda, a 24-year-old polar bear born and raised at the EcoTarium science and nature center in Worcester, Mass. In 2006, Flo S. Tseng, director of the Wildlife Clinic at the Cummings School, joined a team of EcoTarium workers, wildlife officials and other veterinarians who anaesthetized Kenda to assess her overall health and perform routine dental work.

But immobilizing a 600-pound polar bear is a dangerous and complex undertaking. Due to Kenda's age-polar bears in the wild rarely live more than 18 years, although bears in captivity can survive into their 30s-the EcoTarium has no plans to put the bear under again. This past winter, Kenda began acting oddly and zoo officials called in Tseng to consult. But her work was more akin to Perry Mason-style sleuthing than a Marcus Welby, M.D., house call.

Over the course of an hour, Kenda's caretakers had seen the bear lift her right leg and lean to the left for 30 seconds at a time, apparently unaware of her surroundings. Soon she was back to her old self. But what happened to cause that strange behavior? Unable to take blood samples or perform up-close diagnostics, Tseng ran through a mental checklist.

"The first thing you think about is something traumatic," she says of the bear's strange behavior. There were no signs of an accident, so Tseng ruled that out. An infection would likely cause other problems, like lethargy or lack of appetite, but Kenda didn't exhibit those symptoms either.

After consulting with polar bear experts and Cumming School neurologist Philip March, Tseng began to suspect the bear had experienced a transient ischemic attack, or a small blood clot in the brain. Without tests to confirm the diagnosis, Tseng took a conservative approach to treatment. The prescription? Daily aspirin to prevent future clotting-administered via Kenda's favorite snack food, meatballs.

"No one has seen her do it again since, knock on wood," Tseng says.

Tseng returned to the EcoTarium again this summer to determine why Kenda had lost patches of fur on her face and back and was rubbing herself against objects in her enclosure to relieve the itch.

Again, without diagnostic tests like a skin biopsy or scraping, Tseng took a trial-and-error approach. She first asked EcoTarium officials to collect fur samples from Kenda's den while the bear was outside. But the samples didn't offer any clues, although skin problems are common among bears in captivity. So Tseng, aided by Wildlife Clinic intern Erica Smedberg, made a visual diagnosis.

"It didn't look like mange," she says, "but we gave her a de-wormer to be on the safe side." Tseng also prescribed topical steroid mists to relieve the itching and antibiotics to knock out a skin infection like dermatophilus, called "rain rot" in horses. "I'm not sure exactly what helped her, but she's so much better," says Tseng. "She's in good shape for a 24-year-old."

Jacqueline Mitchell may be reached at

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