Hundreds of deer die due to virus in Cook County

Hundreds found dead in Cook, Kane counties; people, pets are safe

A disease that was unknown to local experts until only a few weeks ago is killing hundreds of deer in the Chicago area — and until the first frost comes, those numbers could still go up.

Humans can’t be infected, but so far, it has caused the deaths of roughly 200 deer in Cook County. Six suspect cases have also been reported in Kane County. None have been reported so far in DuPage and Lake counties.

“I have been working here for 30 years, but I have never come across EHD,” said Chris Anchor, wildlife biologist for the Cook County Forest Preserve District.

EHD is short for epizootic hemorrhagic disease, a virus that usually kills deer within a week after infection. It spreads from deer to deer through midges — small, biting flies. And until only a few weeks ago, it had been unknown in this part of Illinois.

EHD has been around in the United States for roughly 60 years, the first outbreak occurring in Michigan and New Jersey in 1955. The disease, which usually appears in the Midwest and Northeast, apparently found its way to this area with a combination of “a mild winter and a hot summer,” Anchor said.

It is a disease that seems to spread rapidly. Anchor heard of the first cases of EHD in Cook County only two weeks ago. And the number of deer deaths attributed to it has doubled in the last week. Cases have been concentrated in Hanover, Schaumburg and Palatine townships.

In Kane County, two cases have been reported to the Illinois Department of Natural Resources. People paddling canoes on the Fox River have reported finding four dead deer, said Bill Graser, wildlife biologist of the Kane County Forest Preserve District. Although he does not know yet if they died of EHD, he considers them to be “suspect cases.”

“And probably there will be more dead deer,” he said.

Graser said he is planning to do research to become more familiar with the symptoms of the disease.

The midge, a small fly that most humans don’t even notice, cannot survive frost, which means that the disease disappears with the onset of frost, usually in mid- or late October.

The disease cannot be transmitted to humans or pets.

Deer usually show signs of the illness a week after getting infected: They lose their appetite and their fear of humans, develop a high fever and respiration problems, and start to drool. Some also bleed internally. They look for bodies of water to cool themselves down. A few hours after these symptoms show, the deer enters a shocklike state, lies down and dies.

Could EHD become a regular phenomenon in this area?

“There is no way to predict that,” Anchor said.

If you find a dead deer, call your local forest preserve district. To report a dead deer on Forest Preserve of Cook County property, call (708) 771-1180. Cook County Forest Preserve District has posting information about EHD on its website,

Virus: Deer that get infected look for water to cool off

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