"Rabbit fever" has health officials worried for hunters, farmers, and outdoor enthusiasts as cases of the rare bacterial illness surge in four states.
Over the last 20 years, the
Centers for Disease Control and Prevention has typically seen about 125 cases per year of
"rabbit fever," or tularemia, The Associated Press reported. But, so far in 2015, there have been 235 cases, 100 of which are in just four states — Colorado (43 cases), Nebraska (21), South Dakota (20) and Wyoming (16).
"This was something we noticed happening here in Nebraska and, when we contacted our colleagues in neighboring states, they were having similar experiences," Dr. Caitlin Pedati, of the Nebraska
Department of Health and Human Services, told LiveScience.com.
The number of "rabbit fever" cases in Colorado this year is nearly 10 times higher than the average number of its annual cases from 2004 and 2014, according to Live Science, while the numbers in Wyoming are up about one and a half times other years' averages.
According to the CDC, tularemia can be transmitted to humans via direct contact with infected animals — such a rabbits or cats — or by eating contaminated food, water, or soil; inhalation from aerosolization (such as landscaping, mowing over voles, hares, and rodents, or other farming activities); or bites from ticks or deer flies.
The Mayo Clinic noted that most people who are exposed to tularemia become sick within three to five days, although it can take as long as 14 days for symptoms to present. Victims can suffer from several types of symptoms, depending on how the bacteria enter the body.
The CDC reported that it is not clear exactly why "rabbit fever" cases have jumped this year, but the agency speculates it could be from "increased rainfall promoting vegetation growth, pathogen survival, and increased rodent and rabbit populations."
Medical workers across the U.S. should take note of the increase to see if the illness starts to rise in other parts of the country as well.
"Healthcare providers should be aware of the elevated risk for tularemia within these states and consider a diagnosis of tularemia in any person nationwide with compatible signs and symptoms," the CDC statement on "rabbit fever" said. "Residents and visitors to these areas should regularly use insect repellent, wear gloves when handling animals, and avoid mowing in areas where sick or dead animals have been reported."