Rare disease discovered in blind deer by WSU pathologists: ‘Do not touch sick animals’

Washington State University (WSU) pathologists confirmed a blind deer was harboring a rare disease.

A news release from WSU reported a mule deer, found in Idaho, had the ocular plague. The plague, according to pathologists, is caused by the bacteria Yersinia pestis and occurs naturally in areas of the western United States. However, Anatomic Pathologist and Associate Professor at WSU Kyle Taylor said that while the disease is common in rodents, it is rare for other animals and not easily passed on to humans.

The deer was spotted by a member of the public on June 9 in Custer County, appearing to be thin, weak and blind.

The next day an Idaho Department of Fish and Wildlife Game officer found and euthanized the deer. Tissue samples and the deer’s eyes were submitted to the Washington Animal Disease Diagnostic Laboratory (WADDL) in WSU for testing, where they confirmed the ocular plague.

More on deer: WA Department of Fish and Wildlife sees uptick in calls about lumps on deer

“Moreover, deer are likely not particularly susceptible to plague, and the case that we detected is believed to be a very rare manifestation of an already rare disease, which has only been reported a handful of times,” Taylor wrote in an email to MyNorthwest on Tuesday.

The plague tends to affect a deer’s eyes, making them blind, according to Pathology Resident at WADDL, Dr. Elis Fisk. Therefore, named the ocular plague.

“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,” Fisk stated via the release.

According to the release, Taylor was aware of previous cases of the disease in Wyoming and Oregon.

However, Staci Lehman with the Washington Department of Fish and Wildlife (WDFW) said the plague is not related to chronic wasting disease (CWD), a deadly disease seen in animals such as deer, elk, moose and reindeer.

Taylor echoed this statement, saying the plague is caused by bacteria, which is endemic to the state, while CWD is a prion disease and is new to Washington. He added there is likely very little concern for the public, hunters or deer populations regarding the ocular plague.

More animal news: Days-old orca whale calf spotted swimming amongst pod in Strait of Georgia

However, Fisk said human exposure to the plague can lead to severe illness and death without early antibiotic treatment. If people do encounter a deer that looks sick, Lehman gave some advice.

“Don’t touch ANY sick animal,” she wrote. “Generally, wildlife diseases don’t pass easily to humans but the CDC recommends not taking the chance, it can also spread disease to areas where it wasn’t already.”

Second, Lehman said to report the sick animal to WDFW so a biologist or vet can look into the situation. To report, head to WDFW’s website.

Julia Dallas is a content editor at MyNorthwest. You can read her stories here. Follow Julia on X here and email her here.