Ticks are widely known to be extremely adept transmitters of disease, with public awareness of Lyme disease increasing exponentially over the course of the 21st century. However, it is also important to bring rare tick-borne diseases to the forefront, as proper preventative measures, diagnosis, and treatment can be vital in saving lives. Tularemia, often called ‘rabbit fever’, is an infection in rabbits and other wild rodents caused by the bacterium known as Franncisella tularensis.
Rabbit fever can be transmitted to humans by contact with infected animal tissues or by tick bites, but isn’t contagious through human-to-human contact. Despite the relatively innocuous nickname, the disease is potentially devastating to the body, so much so that it has been used as a method of bioterrorism in the past, because the infecting bacteria can be freeze dried and sprayed. Symptoms may include red spots on the skin, headaches, muscle pain, shortness of breath, enlarged lymph nodes, fever, and in some cases atypical pneumonia. Antibiotics called streptomycin and tetracyline are commonly used as treatments, though it is not uncommon for patients to have fatigue issues that continue for months after the infection resolves. Overall, 5% of untreated cases are fatal, with less than 1% of treated cases causing death. The severity of the disease is largely dependent on the organism responsible – for instance, untreated respiratory tularemia is estimated to have a fatality rate of over 50%.
While those numbers are worrisome, the disease is fortunately exceedingly rare, with less than one case per million people per year in the United States. Moreover, only those who have occupations or hobbies that include regularly coming into contact with animal carcasses face realistic risks – namely farmers, hunters, veterinarians, foresters, and landscape workers. A vaccine is available for those who face high risk for Tularemia, as the disease can be spread through inhalation of dried animal matter, eating undercooked game, skinning killed animals, and drinking water contaminated with animal carcasses. Of course, the general public is still at risk, with the virus being contractable through the bite of a tick, deerfly, or flea that has fed on a sick rabbit.
Recently, rabbit fever has declined in frequency in the US. According to microbiologist Dr. Charles Patrick Davis, this is likely a combination of two factors: one being increased public awareness, as well as “because wild rabbits are no longer available in markets”. The National Institute of Health is funding several research projects to develop an effective vaccine, as the vaccine given to laboratorians is under review by the FDA and not available to the public. Preventative measures include insect-repellants, not drinking untreated water, using gloves when handling animals (especially rabbits and other small rodents), and cooking game thoroughly.