TORRANCE (AP) — The Catalina Island fox, one of the world’s most endangered species, suffered from frequent tumors for the past decade until scientists discovered a relatively simple solution: treating ear mites.
Research by veterinarians at the University of California, Davis and the Catalina Island Conservancy shows treating ear mites with an anti-parasitic drug helps block cancer, according to the Daily Breeze of Torrance (http://bit.ly/1TlxOBL). Ear infections that can lead to cancer were reduced from 98 percent to 10 percent among foxes that received the drug during a six-month trial.
Efforts to save the foxes, one of the six subspecies of the island gray fox native to the Channel Islands, began in the late 1990s when residents noticed the population declined — a result of canine distemper brought by visitors. The disease killed roughly 90 percent of the island fox population.
As of 1999, roughly 100 foxes remained, said Winston Vickers, associate veterinarian at University of California, Davis, and lead author of the study. As a result, all fox populations on the island were listed as endangered under the federal Endangered Species Act.
Scientists noticed the prevalence of ear mites and the incidence of cancer. A pilot study spearheaded by the conservancy began with 100 foxes to determine whether the drug ivermectin would be effective, administered through a syringe into the animal’s ear canal.
“It’s an oily based treatment that coats the inside of the ear and kills the mites,” said Calvin Duncan, wildlife biologist for the Catalina Island Conservancy and co-author of studies.
Initial lumps that indicate early stages of most tumors are no longer being seen, Vickers said.
In 2014, the fox population was surveyed at 1,717, and Duncan said this year’s data should indicate similar numbers.
The numbers have rebounded so much that the Catalina Island fox may no longer be listed as an endangered species. The designation, which prohibits hunting of the animals and other restrictions, is under review by the U.S. Fish and Wildlife Service.