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Don't touch bunnies. Illinois residents are warned about rabbit fever in their area

What is rabbit fever?

A case of rabbit fever was detected in a rabbit near Chicago, and an unconfirmed human case was reported. Here's what you should know about the disease, which is relatively rare and even rarer in Illinois.
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A case of rabbit fever was detected in a rabbit near Chicago, and an unconfirmed human case was reported. Here's what you should know about the disease, which is relatively rare and even rarer in Illinois.

Cook County, Illinois, health officials are warning residents of a Chicago suburb to keep themselves and their pets away from wild rabbits after a dead one found there last week had the disease tularemia, also known as rabbit fever.

The bacteria that cause the disease are typically spread through the bite of infected ticks and biting flies, according to health officials in Wisconsin, where two dead muskrats in a nature area were also found to have the disease last month, reported WBAY in Green Bay.

Because humans and animals can get the relatively rare disease, residents of Chicago's Tinley Park suburb received letters from city officials over the weekend telling them to keep a close eye and leashes on their pet dogs, CBS Chicago reported.

“It’s bad enough we’ve got to watch for the coyotes. Now we have to watch for the rabbits.” resident Roger Schneider, who worried about his dog's safety, told the CBS station.

The independent news website reported an unconfirmed case of rabbit fever in a human in Cook County, too, tied to exposure to an infected rabbit.

The website reported that state public health officials could not confirm a human had contracted the disease, nor where and when the person might have gotten it. A source told the website that the person was from Tinley Park and had been handling baby wild rabbits.

About 100 to 200 cases of rabbit fever in humans are reported every year in the United States, according to the Illinois Department of Public Health website.

Cases have been reported in all states except Hawaii, according to the Centers for Disease Control and Prevention, but rabbit fever is most common in south-central United States, the Pacific Northwest and parts of Massachusetts.

In 2016, 109 of 230 cases reported in the country came from Kansas, Missouri, Oklahoma, Nebraska and Colorado, according to the CDC.

Three years ago a CDC report found that rates of rabbit fever in the United States were rising, with a bulk of the cases reported in the first nine months of September 2015 occurring in Colorado, Nebraska, South Dakota and Wyoming. CDC officials were unsure what was causing the increase, though they suggested a growing rabbit and rodent population as one possible factor, Newsweek reported.

CDC map.jpg
Reported cases of tularemia, or rabbit fever, in the United States in 2016. CDC

Rabbit fever can be life-threatening if untreated, state and national health officials say, but most cases can be successfully treated with antibiotics.

Tularemia is caused by the bacterium Francisella tularensis, the CDC says. When rabbits hares and rodents — which are especially susceptible — get it they can die in large numbers.

Humans get it several ways, including from tick and deer fly bites, drinking contaminated water, and skin contact with infected animals, according to the CDC.

Up to 80 percent of cases are categorized as "ulceroglandular" — causing skin ulcers and swollen nymph glands — and come from direct contact with infected animals, the Illinois health department says.

Last month, when two dead muskrats tested positive for the disease in the Ken Euers Nature Area in Green Bay, WBAY reported, health officials there urged people to protect themselves and their pets from ticks and biting flies.

State officials in Kentucky issued a similar warning in April — and closed a 240-acre field in Morgantown — when a rabbit tested positive for the disease.

San Diego health officials urged residents to protect themselves and their dogs while hiking or walking in grassy areas in February when several ticks tested positive for rabbit fever, according to CBS 8.

Signs of tularemia in humans can include fever, flulike symptoms, rashes and red lesions on the skin, Matthew Mottel, a veterinarian at Avenue Animal Hospital in Tinley Park, told CBS Chicago.

And in family pets? They could have rabbit fever if "a dog just isn’t acting right, maybe they are a bit lethargic so decrease in energy, maybe decrease in appetite," Mottel said.

Health officials stress that people should not touch dead rabbits, or any other dead animal for that matter, and to call animal control authorities when possible.

Disease cases from mosquito, tick and flea bites more than tripled in the U.S. from 2004 to 2016, with tick-borne illness seeing the most dramatic increase. The CDC says many local health departments lack the tools to protect people.