Human case of rare insect-borne disease reported in Boulder County

DENVER (KDVR) — Boulder County is reporting its first human case of tularemia in 2024, following a case of tularemia in a Jefferson County resident was reported earlier this summer.

However, it isn't the first reported case of tularemia in the county this year. In July, a family's cat tested positive for the so-called "rabbit fever."

Tularemia is a rare disease that is carried most commonly by infected insects, such as ticks and deer flies, but can also be transmitted through infected animal tissues, and then carried by larger animals like rabbits or outdoor pets. If the animal particles become airborne, the bacteria can also be inhaled.

According to Boulder County public health officials, the infected person lives near the city of Boulder and began experiencing fever symptoms on Oct. 2. They then experienced progressing symptoms, including an altered mental status and fluid in the lungs.

The individual has been diagnosed with pneumonic tularemia, a rare respiratory form of tularemia, Boulder officials shared.

The individual told officials they had contact with a cat and dog during their exposure period, but neither animal has yet to show signs of illness. The individual could not confirm a recent insect bite with officials, but that remains the possible infection source.

Warning signs will be posted in the area where the infected person could have contracted the infection.

“It’s essential to take precautions around wild animals and avoid contact, as tularemia, while rare, poses serious health risks,” said Carly Wilson, Boulder County Public Health Vector Epidemiologist/Environmental Health Specialist, in a release. “If you develop a fever and know tularemia has been found in your area, or if you think you may have been exposed, be sure to mention it to your healthcare provider.”

To prevent the spread of tularemia, health officials recommend:

• Avoiding areas frequented by wild rabbits and rodents
• Apply insect repellent containing DEET if entering an area frequented by wild rodents
• Prevent pets from hunting or consuming wild animals
  • Prevent tick exposure to pets, especially cats
• Avoid contact with wild rodents, including rabbits and squirrels
• Do not touch sick or dead animals with bare hands
• Avoid drinking untreated water
• Do not mow over an animal carcass, as it can turn the infection into an aerosol
• Consider wearing a dust mask while mowing or landscaping
• Avoid tick exposure

If you have a high fever or swollen lymph nodes, seek medical care. If your pet shows signs of illness, consult a veterinarian.

For more information on tularemia, visit cdc.gov/tularemia or boco.org/Tularemia, or contact Boulder County Public Health at 303-441-1564. To report a rabbit die-off, call 303-441-1564.