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Saving the Island Fox
Ear mites, infectious diseases lead scientists down conservation road
by Heather Grimshaw
From AnimalNews 9.3
Santa Catalina Island foxes are not able to trumpet the work of wildlife veterinarians like Dr. Linda Munson and a team of professionals working to spring them from the endangered species list. But they may be able to hear celebratory horns coming from the Morris Animal Foundation (MAF) office in Denver.
Several MAF-funded studies have focused on the health
of these tiny, docile animals, which live exclusively on the six largest Channel Islands of southern California. Island foxes, the largest terrestrial mammal on the Channel Islands, were added to the endangered species list in 2004 after the population dwindled from 6,000 to fewer than 1,300 over a seven-year period.
Munson—a veterinary pathologist who specializes in wild canid and felid diseases—was contacted by veterinarians and biologists who were concerned about the population decline, which was later attributed to golden eagle predation and a canine distemper epidemic.
A team of veterinary experts, including Drs. Munson, Jonna Mazet, Deanna Clifford and Winston Vickers, responded to that call.
Over the last 10 years, MAF has funded the work of this multidisciplinary research team that expanded to include veterinary epidemiologists, geneticists, oncologists and virologists. At various stages, team members studied how foreign pathogens affect the foxes, and they now hope to evaluate how the loss of genetic diversity impacts the foxes' ability to respond to stresses of climate change, fires and everyday life.
Recently researchers assessed exposure to infectious diseases and, through extensive surveillance, discovered a high prevalence of ear canal cancer. The cancer not only interferes with well-being, but it may also delay population recovery, says Munson.
Researchers believe ear tumors are related to the presence of ear mite infections, which lead to chronic inflammation and may induce cancer. Previously, the team ruled out environmental toxins and viruses as causes for the ear canal cancer.
Currently, Dr. Warren Johnson at the National Cancer Institute assesses genetic predisposition to ear canal cancer, and Munson conducts a pathology surveillance that looks for infectious diseases.
"We plan to investigate what specific viruses are circulating
through the fox populations... [and] will continue to monitor
the population for emerging diseases," she adds.
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