Larimer County and Colorado State University Report a Case of Tularemia in Wildlife

The Larimer County Department of Health and Environment and Colorado State University’s Environmental Health Services report that a weasel found dead at the Environmental Learning Center was infected with tularemia, a bacterial disease common in wildlife.

The Centers for Disease Control in Fort Collins tested the weasel and two beavers and confirmed that the weasel was infected with tularemia. Though the beaver remains did not yield conclusive test results, health officials suspect that they also were infected. Because the disease can affect humans and domestic animals as well as wildlife, staff at the Environmental Learning Center, located at the intersection of Drake Road and Ziegler Road, have posted signs advising that all visitors stay on trails, keep animals on leashes and avoid touching wildlife. Environmental Learning Center staff also will be on hand to discuss precautions with visitors. Several antibiotics, including streptomycin, are effective in treating the disease; however, people are urged to prevent infection by taking proper precautions when handling animals or visiting areas where tularemia cases have been reported.

While many kinds of wild and domestic animals may be infected with tularemia, rabbits are most often involved. Other wildlife that may become infected include muskrats, voles and beavers. Insects, primarily certain ticks and deer flies, can become infected with tularemia bacteria and transmit the infection to animals by introducing the bacteria when biting.

Humans may become infected through the bites of infected insects, such as wood ticks and deer flies, but are most commonly infected from handling infected animals. Hunters are at risk of exposure when skinning or butchering wild animals when their skin or mucous membranes come into contact with the blood or tissues of infected animals. People also may become infected by eating insufficiently cooked rabbit meat. Less common means of spread include drinking contaminated water and inhaling dust from contaminated soil or handling contaminated pelts or paws of infected animals. Another uncommon route of spread is from the bite of a skunk, coyote, squirrel, dog or cat whose mouth came in contact with an infected animal.

Tularemia infection can be prevented by taking proper precautions when handling animals, especially rabbits. Sick or dead animals found in the wild should not be handled. Hunters should wear protective gloves when handling or skinning rabbit carcasses. Wild rabbit and rodent meat should be cooked thoroughly. Ticks and deer fly bites can be prevented by using effective insect repellents. Drinking, bathing, swimming or working in untreated water should be avoided in areas where infection is common among wild animals. People also should check domestic animals for ticks and for symptoms.

Symptoms generally appear in two to 10 days, usually about three to five days after exposure. Tularemia may be first recognized by the presence of an ulcer-type of lesion at the insect bite site and enlarged, swollen, painful glands near the site. A sore throat, intestinal pain, vomiting and diarrhea may result from ingesting the organism in water or meat. Inhaling the organism may produce a fever alone or along with pneumonia. Tularemia infections may be mistaken for plague, cat scratch fever, staphylococcus or streptococcus infections.

No cases of human tularemia have been reported in Larimer County this year or in 2001.