McHenry County, IL
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What Is Rabies?
Rabies is a deadly but preventable viral disease that affects the central nervous system of mammals, including humans. It is typically spread through the saliva of an infected animal, often by a bite or scratch.
Once symptoms appear, rabies is almost always fatal. That’s why prompt evaluation and treatment are essential. For more information on how the rabies virus spreads and how it can be prevented, visit:
Learn more about rabies and PEP →
What We Do
The McHenry County Department of Health (MCDH) investigates all reported animal bites and potential rabies exposures in McHenry County.
Our response includes:
- Reviewing bite and animal exposure reports
- Assessing rabies risk based on species and circumstances
- Coordinating animal quarantine or testing when appropriate
- Recommending and guiding individuals through rabies post-exposure prophylaxis (PEP) if needed
- Monitoring trends in rabies activity across the county
Why We Do What We Do
Rabies is one of the deadliest diseases known—once symptoms begin, it is nearly always fatal. However, timely medical care and coordinated public health response can prevent illness and save lives. Investigating animal bites and exposures helps protect individuals from rabies, while also reducing the spread of this disease in our community.
The McHenry County Department of Health works to ensure that:
- Exposures are assessed quickly and accurately
- High-risk situations are identified and addressed in a timely fashion
- Infected or potentially rabid animals are not released back into the public
- Residents receive guidance and access to treatment when needed
- Potential rabies exposures are urgent, not emergent
By responding to every reported bite and exposure, the MCDH plays a critical role in preventing the spread of rabies, supporting safe human-animal interactions, and safeguarding the health of McHenry County residents.
Animals & Their Risk Level
Domestic cats and dogs over the age of 4 months are required by Illinois law to be vaccinated against rabies, so they are typically at lower risk for carrying the disease. These animals are also more easily contained for observation purposes, even if they are not up to date.
Bites from wild animals, such as foxes, coyotes, wolves, raccoons, and skunks, fall into a higher risk category. Bats typically raise the highest concern for rabies.
What Is a Potential Rabies Exposure From a Bat?
- If an actual bite from a bat occurs (bat teeth are extremely small, so the bite may go unnoticed)
- If someone wakes up to a bat in the room with them
- If a bat is found in a room with an individual who is a child, a person who has a cognitive disability or memory issues (such as dementia), or an individual who is intoxicated or high
What Should I Do If I Am Bitten or Am Unsure If I Was Bitten?
A bite is defined as a scratch, abrasion, puncture, or any break in the skin from the tooth of an animal. If a bite occurred, clean the wound immediately and remove as much saliva as possible. Seek medical care, as some bites may require treatment such as antibiotics.
If you're uncertain whether a bite occurred, call MCDH's Communicable Disease Program at (815) 334-4500. A registered nurse will ask questions to determine exposure risk and guide next steps. In some cases, especially with higher-risk animals that cannot be observed or tested, post-exposure prophylaxis (PEP) may be recommended.
How Is the MCDH Made Aware of a Bite?
Most bites are reported when a victim is treated at urgent care or an emergency room. Some are self-reported via fax or phone to Animal Control. A bite report form is filled out by the facility or over the phone. If the bite involved a high-risk animal, a Communicable Disease Nurse will call for an interview, as well as provide education and guidance.
Animal bite and exposure reports may come from:
- Hospitals, emergency departments, or urgent care providers
- Individuals who have been bitten or exposed
- McHenry County Animal Control staff
- Schools, residential properties, or regulated facilities
- Local law enforcement or municipal agencies
What Is PEP?
Post-exposure prophylaxis (PEP) is a treatment for potential rabies exposure. It consists of human rabies immune globulin (HRIG) and a series of rabies vaccines. The HRIG provides immediate protection while the vaccine builds longer immunity.
PEP Administration Process
- Day 0: HRIG and the first vaccine dose (in different anatomical sites)
- Day 3: Second vaccine
- Day 7: Third vaccine
- Day 14: Fourth vaccine
- Day 28: Fifth dose (if needed, e.g., for immunocompromised individuals or if earlier doses were improperly administered)
As the rabies vaccine is costly and has a short shelf-life, individuals will most likely need to go to an emergency room (ER) to receive the HRIG and first dose. Subsequent dates can then be arranged through an outpatient setting or infusion center. Talk with ER staff to see what can be arranged.
How We Investigate
The priorities of an animal exposure investigation are to evaluate the risk of rabies transmission to the individual and the public, implement appropriate follow-up (such as testing or quarantining the animal, or initiating rabies PEP), educate those involved on prevention, and ensure all public health protocols are followed to minimize future risk.
Once an animal bite or exposure report is received, the Animal Exposure Response Team—consisting of Animal Control, Communicable Disease, Environmental Health, and Epidemiology—works together to:
- Review exposure details and assess rabies risk
- Monitor or test the animal involved, if able
- Determine if post-exposure prophylaxis (PEP) is recommended
- Provide follow-up and education to the exposed person
- Track trends and maintain surveillance of confirmed rabies cases
Each investigation is documented, and when appropriate, a final summary is shared with stakeholders or used to inform public messaging.
Potential rabies exposures are urgent, not emergent. If you had a concerning animal bite or exposure, call your healthcare provider or the MCDH at (815) 334-4500.
Information for Providers
What We Do
MCDH investigates all domestic and wild animal bites. Reports should be submitted to both the Animal Control and the Communicable Disease divisions.
Healthcare Provider's Responsibility
Provide wound care as indicated and complete the MCDH Bite Report Form. Fax the completed form to:
- Animal Control: (815) 334-4682
- Communicable Disease: (815) 334-0191
If the bite victim is completing the form, please encourage legible handwriting and ensure all fields are completed as thoroughly as possible.
PEP or No PEP?
PEP is not always necessary. For example, bites from dogs and cats—whether owned or stray—may not warrant it. However, bites from higher-risk animals such as bats, raccoons, muskrats, and foxes typically require stronger consideration. Refer to the rabies exposure algorithm poster below or contact MCDH Communicable Disease at (815) 334-4500 for guidance. After-hours calls are directed to our on-call service.
Rabies Vaccine Administration Tips
Common errors include giving HRIG and the vaccine in the same site, or administering either one in the gluteus. HRIG should also not be given to someone who previously completed the vaccine series.
Refer to the rabies PEP poster below for administration guidance.
Animal Control
What Does McHenry County Animal Control Do?
After a bite is reported, an activity report is created and dispatched to an animal control officer. All biting animals must be seen by a licensed veterinarian within 24 hours of the bite and undergo a 10-day rabies quarantine. The location of the quarantine depends on the animal's vaccination status. A currently vaccinated animal may be quarantined at the owner's home and must be examined by a vet on the first and last day of the quarantine. An unvaccinated animal must complete the 10-day quarantine at a veterinary facility. An animal control officer will provide paperwork outlining the owner's legal responsibilities under state and local ordinances.
Quarantine
A rabies-infected dog or cat typically shows symptoms within 10 days of exposure. The quarantine period applies to animals that appear healthy at the time of the bite. If any signs of rabies develop during the quarantine, the animal should be reported immediately and sent for testing.
Wild Animals
Wild animals present a higher rabies risk than domestic dogs and cats. McHenry County Animal Control (MCAC) responds to reports of sick or injured wild animals or those posing a significant community health risk, including those found inside homes. Officers are trained to assess rabies risk in wildlife and use exposure forms to evaluate potential contact. While all mammals can carry rabies, species such as raccoons, skunks, foxes, coyotes, and wolves have higher incidence rates in the U.S., with bats posing the greatest risk in Illinois.
Animal Control Ordinance for McHenry County
Public Health Ordinance Article VI (English | Español): Effective December 1, 2022
Communication
The McHenry County Department of Health is committed to transparency throughout the investigation process. We share information with affected individuals, relevant businesses and establishments, policymakers, and the public, while protecting confidentiality and not compromising investigations.
Our Public Information Officer (PIO) collaborates with experts from communicable disease, epidemiology, and environmental health teams to develop clear, accurate communications. All messaging is approved by the Public Health Administrator before release.
When investigations involve partners such as IDPH, CDC, or local schools, the PIO coordinates to ensure consistent and accurate information reaches the public.
Media inquiries during outbreaks are managed by the PIO working with health experts to provide factual and relevant responses.
How You Can Help
- Stay Informed: Follow MCDH on social media and check the website for updates on outbreaks.
- Public Input: Participate when public input is requested during investigations via announcements or social media.
- Preventive Measures: Practice good hygiene and adhere to food safety guidelines to reduce illness spread.
After an investigation concludes, findings are shared with involved partners and affected parties. A news release announces the investigation’s completion and directs the public to the final report.
Additional Resources
- What Should I Know About Animal Bites (PDF)
- Rabies PEP Decision Poster (PDF)
- Bat Encounters...What to Know (PDF)
- Bat & Wildlife Removal Services (PDF)
- Communicable Diseases Data and Reports
By working together, we can maintain a healthy McHenry County. For questions or concerns, please contact the McHenry County Department of Health.
Contact Information
McHenry County Department of Health
Phone: (815) 334-4510
Communicable Disease Program
Phone: (815) 334-4500
Animal Control & Adoption Center
Phone: (815) 459-6222