First human case of rare rodent, insect-carried disease reported in Colorado

DENVER (KDVR) — A rare disease associated with rodents, ticks and deerflies has been confirmed in a Colorado resident.

Jefferson County Public Health said the resident had tularemia — this is the first positive human case in Jefferson County in 2024.

Tularemia is a bacterial disease also known as “rabbit fever.” It can be transmitted to humans through infected insects, animals, contaminated food or water or airborne bacteria.

In June, Boulder County identified the disease in a dead rabbit.

“While tularemia is rare, it is important for residents to be aware of the symptoms and take preventive measures,” said Rachel Reichardt, an environmental health specialist at Jefferson County Public Health. “Prompt treatment with antibiotics is effective, so early diagnosis and medical attention are crucial.” 

What are the symptoms in humans?

According to Jefferson County Public Health, the symptoms can vary depending on how the infection was transmitted.

Some symptoms include fever, non-healing skin ulcer at the site of infection and swollen and painful lymph glands. If the infection was caused by ingesting contaminated food or water, the person might have a sore throat, mouth sores, abdominal pain and diarrhea.

If the bacteria is airborne and inhaled, the symptoms may include pneumonia, fever, chills, headache, muscle aches, dry cough and progressive weakness. 

Is Tularemia treatable?

Jefferson County Public Health said tularemia can be treated successfully and cured. If you have any of the symptoms listed and think you may have been in contact with an infected animal or insect, see your physician right away.

In 2023, there were four human cases of tularemia in Boulder County and 11 total in Colorado.

In the past 13 years, Colorado has seen an average of 5.8 human tularemia cases, except in 2015 when there was a spike with 52 reported cases, according to the state health department.

How to prevent exposure

Now that tularemia has been identified in both humans and animals, Jefferson County Public Health has these tips on how to stay safe.

• Use insect repellent while outdoors  
• Avoid all contact with wild rodents
• Do not feed or entice any rodent or rabbit into your yard or patio 
• Get rid of piles of lumber, trash and weeds around your home
• Avoid touching sick or dead animals, or wear gloves if necessary  
• Do not mow over dead animals
• Do not drink untreated surface water, like lakes, ponds and rivers 
• Be sure to cook meat thoroughly before eating 
• Keep pets on a leash while in areas where contact with wildlife is possible 
• Consult a veterinarian for any pet interaction
• Provide immediate veterinary care for sick pets and do not handle sick pets without using hand and face protection

More information on the rare disease can be found on Jefferson County Public Health’s website.