Rare ‘Rabbit Fever’ That Causes Vomiting and Chills in Humans Detected in Colorado, Health Officials Say

Health officials in Larimer County, Colorado, have confirmed the presence of tularemia in a dead rabbit discovered in the town of Berthoud. The Larimer County Department of Health and Environment (LCDHE) issued the alert on June 9, warning residents that the bacteria Francisella tularensis, which causes the infectious disease known as “rabbit fever,” is endemic to the region.

How Tularemia Spreads to Humans

Tularemia is a highly infectious disease that transmits to humans through several pathways, according to the Cleveland Clinic. Infection typically occurs following contact with bodily fluids from infected animals, exposure to contaminated food or water, or insect bites.

The Centers for Disease Control and Prevention (CDC) identifies several tick species capable of transmitting the bacteria, including the American dog tick, the lone star tick, and the Rocky Mountain wood tick. Beyond ticks, the bacteria is commonly found in rabbits, hares, and various rodent populations.

Symptoms and Treatment

Infection in humans often results in a range of systemic symptoms. According to the Cleveland Clinic, individuals may experience fever, chills, nausea, vomiting, muscle aches, abdominal pain, and swollen lymph nodes. Medical professionals typically treat confirmed cases using antibiotics.

Preventative Measures for Residents

To reduce the risk of exposure, health officials have released specific guidance for residents in northern Colorado. Dr. Paul Mayer recommends using effective insect repellent and performing thorough skin checks for ticks after spending time outdoors. Furthermore, residents should maintain distance between themselves, their pets, and any wild animals, particularly rabbits and squirrels.

Additional safety recommendations include:

• Wear gloves while gardening and wash hands frequently before eating or touching the face.
• Use a dust mask when performing tasks that disturb soil, such as mowing, digging, or using leaf blowers.
• Wear shoes when outdoors, especially in areas where dead wildlife may be present.
• Use protective gloves if it becomes necessary to remove a dead animal from a property.

The LCDHE requests that residents report any instances of three or more dead animals found in the same vicinity within a two-week period to the Zoonosis Team at 970-498-6666.

What May Happen Next

Because the disease is endemic to the area bordering Wyoming, health officials suggest it is possible that the bacteria is present in other locations beyond the initial discovery site in Berthoud. If environmental conditions favor tick activity or animal contact, the potential for further wildlife cases remains. Residents are advised to continue monitoring their immediate surroundings for clusters of animal deaths, which could signal a higher concentration of the bacteria in the local ecosystem.

Frequently Asked Questions

What is tularemia?
Tularemia is a highly infectious disease caused by the Francisella tularensis bacterium, often referred to as “rabbit fever.”

How can I protect myself from infection?
Officials recommend using insect repellent, checking for ticks, wearing gloves while gardening, using a dust mask while performing yard work like mowing, and keeping children and pets away from wild animals.

What should I do if I find dead animals on my property?
Use protective gloves to move the animals and report clusters of three or more dead animals in the same area over a two-week period to the LCDHE Zoonosis Team at 970-498-6666.

Have you taken steps to tick-proof your outdoor gear this season?