A rare disease known as rabbit fever (also called tularemia) that was thought to have been largely conquered decades ago has made a resurgence in the U.S.
Health officials have only seen a yearly average of about 125 cases of tularemia, in the past 2 decades, but there have been 235 cases this year, the U.S. Centers for Disease Control and Prevention (CDC) said in a report published Thursday. That’s the most cases reported in a year since 1984.
At least 100 of this year’s cases have been in Colorado, Nebraska, South Dakota and Wyoming. Patients have ranged in age from 10 months to 89 years. The disease claimed the life of an 85-year-old man and landed 48 others in the hospital.
“This was something we noticed happening here in Nebraska, and when we contacted our colleagues in neighboring states, they were having similar experiences,” said Dr. Caitlin Pedati, of the Nebraska Department of Health and Human Services and the CDC and lead author of the report. Pedati said that health authorities in Colorado, South Dakota and Wyoming were also noticing more cases of rabbit fever, but other states beyond those were not showing such a dramatic increase.
Colorado has seen 10 times the average number of yearly cases in that state between 2004 and 2014. Wyoming has seen 1-1/2 times the normal yearly cases.
Scientists aren’t sure what’s causing the dramatic uptick in cases, but they theorize that weather conditions, including increased rainfall, have likely helped rodents – and bacteria – survive. Rabbit fever is spread by ticks and deer flies that pick up the bacteria from rabbits and other small mammals and then bite humans. The infection can also be spread through human contact with dead mammals, drinking contaminated water and by inhaling the bacteria.
Rabbit fever can be life-threatening but is usually treatable with antibiotics. Symptoms typically depend on how the bacteria entered the body. If an individual becomes infected by touching a dead animal without gloves, for instance, they may exhibit skin ulcers and swollen lymph nodes. Someone who accidentally inhales the bacteria would show throat and lung problems.
It takes about 3-5 days for symptoms of tularemia to start, though it could take longer, according to the CDC. Fever and chills, muscle or joint pain, a cough or trouble breathing, skin ulcers, pink eye, stomach pain with vomiting and diarrhea and sore throat are all general symptoms.
Tularemia is 1 of 5 diseases that experts believe have the greatest potential to be used as biological weapons. Anthrax is also on that list.
 Associated Press