The Larimer County Department of Health and Environment has confirmed the first human case of tularemia in a county resident in 2016. This patient developed a lung infection, and may have been exposed while mowing the yard or gardening at home in an urban subdivision. Soil can be contaminated by tularemia-causing bacteria from the droppings or urine of sick animals, most often rabbits. When a person mows, blows leaves, or turns up the soil, these bacteria can aerosolize and be inhaled, causing pneumonic tularemia.
All warm-blooded animals are susceptible to tularemia, including livestock and pets such as dogs, cats and birds, however these bacteria normally occur in nature in rabbits and hares, as well as in small rodents, voles, muskrats, and beavers. A recent die-off of rabbits or rodents in a neighborhood suggests a possible tularemia outbreak among the animals in that area. The bacteria these animals shed can persist in the soil or water for weeks, and it takes very few bacteria to cause an infection.
Tularemia can be transmitted to people, such as hunters, who have handled infected animals. Infection can also arise from the bite of infected insects (most commonly ticks and deer flies); by exposure to contaminated food, water, or soil; by eating, drinking, putting hands to eyes, nose, or mouth before washing after outdoor activities; by direct contact with breaks in the skin; or by inhaling particles carrying the bacteria (through mowing or blowing vegetation and excavating soil). In recent years, most human tularemia cases along the Front Range have been attributed to activities involving soil and vegetation.
Typical signs of infection in humans may include fever, chills, headache, swollen and painful lymph glands, and fatigue. If tularemia is caused by the bite of an infected insect or from bacteria entering a cut or scratch, it usually causes a skin ulcer or pustule and swollen glands. Eating or drinking food or water containing the bacteria may produce a throat infection, mouth ulcers, stomach pain, diarrhea and vomiting. Inhaling the bacteria may cause an infection of the lungs with chest pain and coughing.
Tularemia can be effectively treated with antibiotics. Should you have any of these early signs, seek medical attention as soon as possible. Untreated tularemia can lead to hospitalization and may be fatal if not diagnosed and treated appropriately.
Gardeners, landscapers, mowers, outdoor workers, and others participating in leisure activities outside are advised to:
- Wear gloves when gardening or planting trees, and always wash hands before eating or putting hands to mouth, nose, or eyes
- Wear a dust mask when mowing or blowing vegetation, or excavating or tilling soil
- Wear an insect repellent effective against ticks, biting flies and mosquitoes (DEET, picaridin, or IR3535 are good choices)
- Wear shoes, rather than going barefoot, on grassy lawns, especially if dead rabbits or rodents have been seen in the neighborhood
- Never touch dead animals with bare hands