Colorado has seen 11 human cases of tularemia, or rabbit fever, since May of this year, a significant increase from the average number of cases annually, which was fewer than four, according to the state health department.
The following are five things to know about the outbreak and the illness.
1. Tularemia is caused by Francisella tularensis, a bacterium. While rabbits, hares and other rodents are especially susceptible to the illness and often die in large numbers during outbreaks, humans can also get infected, according to the Centers for Disease Control and Prevention.
2. Humans can become infected in a number of ways, including tick and deer fly bites, skin contact with infected animals, ingestion of contaminated water, laboratory exposure, inhalation of contaminated dusts or aerosols, or the result of bioterrorism, according to the CDC.
3. The large increase in the number of human cases of rabbit fever in Colorado have been attributed to conditions promoting more vegetation as well as a lack of rabbit predators due to outbreaks of mange and West Nile virus that have killed foxes and other predators, according to a Fox News report.
4. Tularemia can be life-threatening, but can usually be successfully treated with antibiotics, according to the CDC.
5. Tularemia can be difficult to diagnose, since it is a rare disease and can be mistaken for other illnesses. Isolation is not recommended for tularemia patients, according to the CDC, because it does not transmit human-to-human. Streptomycin is the drug of choice to treat tularemia, and tetracyclines can be a suitable alternative, the CDC reports. Find more information for clinicians on the illness here.