Tularemia, widely known as rabbit fever, is a relatively rare disease that is spread among animals and people by biting insects and by contact with infected carcasses; it has been reported this spring and summer in Larimer and Boulder counties – indicating a need for awareness and precautions.
One person in Boulder County contracted tularemia in May and died of medical complications not related to the disease. Another human case was later diagnosed in northern Larimer County.
To avoid tularemia, avoid all contact with wild rodents, including squirrels and rabbits.
According to the Larimer County Health Department, tularemia already has been confirmed in several rabbits, prairie dogs and pet dogs in the county this year. In 2014, there were 16 human cases of tularemia in Colorado, says the Colorado Department of Public Health and Environment.
The Veterinary Diagnostic Laboratories at Colorado State University conduct tests to identify the disease and play a key role in tracking infection.
Tularemia is caused by the Francisella tularensis bacteria. Rabbits, rodents and cats are very susceptible to infection. Dogs are not as susceptible but may carry infected ticks.
Dogs and cats contract tularemia by eating infected rabbits or other animals, by drinking contaminated surface water, through tick and deer fly bites, and by exposure to contaminated soil through broken skin.
In humans, tularemia is most commonly transmitted through handling infected animals, and it can also be transmitted from a bite by an infected tick or deer fly. The highest risk is from handling dead infected animals, especially if people are skinning or eating them. Other routes include exposure to contaminated food, water, or soil, by eating, drinking, or direct contact with breaks in the skin, and by inhaling dust from mowing or moving contaminated hay, grass, grain or soil.
Tularemia cases in humans in Larimer County seem to be tied to soil, said Katie O’Donnell, Larimer County Department of Health and Environment. “This tends to be people who garden, or people who mow the lawn or landscape.”
How to avoid tularemia:
- Avoid all contact with wild rodents, including squirrels and rabbits.
- Hunters should avoid hunting and eating highly susceptible animals (rodents, rabbits and squirrels) during periods of transmission (warmer weather when insect vectors are active).
- Do not feed wildlife.
- Do not handle sick or dead animals. If you must move a carcass, place it in a garbage bag using a long-handled shovel, and place the bag in an outdoor garbage can.
- Wear an insect repellent with DEET, IR3535 or lemon eucalyptus oil to repel ticks, biting flies and mosquitoes.
- Wear shoes in areas where rabbits have died because the bacteria can live for several months.
- Wear a dust mask when mowing or blowing vegetation in areas where rabbits have died.
- Do not allow pets to hunt or eat wild rodents or rabbits. Infected pets can transmit the disease to people.
- Avoid ticks. The best protection for pets, especially cats, is to keep them indoors. If outdoors with pets, keep them out of heavily wooded areas.
- People and animals should not drink unpurified water from streams or lakes.
- Don’t mow over animal carcasses, and use a dust mask when doing landscape work.
Signs/symptoms of tularemia:
- Skin ulcers
- Swollen and painful lymph glands
- Inflamed eyes
- Sore throat
- Mouth sores
- Sudden fever
- Muscle aches
- Joint pain
- Dry cough
- Difficulty breathing
- Bloody sputum
- Respiratory failure
If you suspect tularemia:
- See a health care provider if you become ill with a high fever and/or swollen lymph nodes. Tularemia is treatable with antibiotics when diagnosed early.
- Contact a veterinarian if your pet becomes ill with a high fever and/or swollen lymph nodes.