Plague found in blind Idaho deer

PULLMAN, Wash. - An emaciated, blind mule deer found in Idaho earlier this year has been confirmed to have a rare case of plague, said scientists from Washington State University.

Last week, the school said the animal was spotted and reported on June 9 in Custer County, and the next day the deer was found and euthanized by an Idaho Department of Fish and Game officer.

The Washington Animal Disease Diagnotic Laboratory in the WSU College of Veterinary Medicine received tissue samples and the deer's eye to be tested.

Results confirmed plague was only detected in the deer's eye samples and not in its organs and other tissues.

"Deer and other ruminants don’t appear to be particularly susceptible to plague, but in the few published cases, it has specifically been found in the eyes," said Dr. Elis Fisk, a pathology resident at the lab. "The disease doesn’t necessarily kill the deer on its own, but it causes blindness, likely making them vulnerable to predators and significantly reducing their chances of survival."

A female mule deer or doe in sagebrush in a valley in Idaho.. (Photo by: Jon G. Fuller/VWPics/Universal Images Group via Getty Images)

Plague occurs naturally in the western United States and circulates among wild rodents and other animals. It's caused by the bacterium, Yersinia pestis. The disease most often appears as lesions in the eyes of deer, leading to blindness, a condition known as ocular plague.

"When we received the samples, the eyes appeared highly abnormal," Fisk said. "Usually, when you cut into the eye, it contains clear fluid, but in this case, it was filled with thick, reddish-brown debris. The other interesting thing was the retina was detached, and there was significant inflammation and necrosis."

All samples were destroyed after testing for safety reasons.

There have been five cases of plague in deer that were reported, none of which was in Idaho.

Wildlife officials are advising hunters and other people to avoid contact with animals that are blind or have abnormal behavior. If they do encounter any, report the location and species of the animal to their state wildlife agency.

Officials said if humans are exposed to plague, it can result in severe illness and death if not treated early.