12/23/2025
Dear peeps, We routinely get notifications about dogs who test positive for Leptospirosis in Cook, Will and DuPage counties. This is an important zoonotic disease that can cause serious illness in humans. This morning we were issued a public health announcement about a dog testing POSITIVE for Rabies in Cook county. Please see the attached notification. Rabies is 100% fatal in humans if left untreated. Those employees in contact with this dog, as well as the individual bitten, will now have to undergo Rabies prophylaxis. Please be sure that your pet's Rabies vaccination is up to date. Let us know if you have any questions!
TO: Illinois Local Health Departments, Animal Controls, and Veterinarians
FROM: Communicable Disease Control Section
DATE: December 22, 2025
SUBJECT: Rabid Dog Identified in Chicago
A Chicago dog tested positive for rabies by direct fluorescent antibody testing on December 19 at the IDPH Chicago lab. The test was repeated, and the repeat test was also positive. This is the first rabid dog in the state since 1994 and the first rabid dog in Cook County since before 1964. This dog was younger than a year old and was adopted by a Chicago household from a Chicago rescue. The dog was from a litter of puppies sent to the Chicago rescue from a Florida rescue group in May 2025.
The dog had behavioral issues throughout its life which got worse on December 16. Behaviors included growling, snapping, increased barking and anxiety. The dog was rabies vaccinated and rabies was not suspected. Due to the dog’s behavior, it was euthanized on December 18. Because the dog had bitten someone on December 11 and per state law must be held 10 days or tested for rabies, it was tested for rabies and was found to be rabies positive.
Currently the source of rabies for this dog is under investigation. Strain typing to determine whether the strain is bat, fox or raccoon strain is being conducted. This will help direct efforts in determining a source. The Illinois owners reported no known exposures to wild animals including bats, while the dog was living with them. Currently, bats are the reservoir for animal rabies in the state. The last skunk positive for rabies in Illinois was in 1998 and the last raccoon positive for rabies in the state was in 1983.
The dog was vaccinated for rabies in June 2025. Because the exposure source is not yet identified, it is possible the dog was exposed to a rabid animal prior to rabies vaccination.
Chicago Department of Public Health (CDPH) and Illinois Department of Public Health (IDPH) are evaluating any people in contact with the dog to determine if rabies post-exposure prophylaxis (PEP) should be recommended for them. In addition, Cook County Animal and Rabies Control (CCARC) are following-up with owners of littermates to the rabid dog and to dogs that this rabid dog may have been in contact with including at a doggy day care. Any dog that is up to date on rabies vaccination and was in contact with the rabid dog should get a booster rabies vaccination and be held in a home quarantine for 45 days with close monitoring for any symptoms suggestive of rabies.
The incubation period for rabies is typically from 20 to 60 days in animals but can be up to one
year. Symptoms of rabies in animals include aggression, restlessness, hypersensitivity,
excessive slobbering, lethargy, weakness, inability to raise the head or make sounds and
hydrophobia.
This situation provides a reminder that pre-exposure rabies vaccination in veterinarians and
their staff helps protect them against unknown rabies exposures and reduces the number of
vaccines needed for rabies post-exposure treatment. It is also a reminder of the importance of
keeping pet rabies vaccinations up to date to reduce the risk of rabies.
