June 26, 2003 -- The latest health threat: Fuzzy bunnies. The CDC is rushing to investigate rabbit fever -- tularemia -- in three Nebraska men.
It's not particularly shocking that giant Gambian rats carry monkeypox. But bunny rabbits? Sad, but true. Wild bunnies can be just as big a health threat as exotic, oversize rodents.
Unlike monkeypox, rabbit fever isn't new to the U.S., says Lawrence T. Glickman, VMD, DrPH, professor, of veterinary epidemiology and environmental health at the Purdue School of Veterinary Medicine, West Lafayette, Ind.
"Tularemia is often out of sight and out of mind to most doctors," Glickman tells WebMD. "In the U.S. there are 20 to 50 reported cases a year, and this is clearly an underestimate of what really occurs. People usually get it from direct contact with rabbits -- hunters mostly, who nick themselves while skinning rabbits. And even that is relatively rare."
A person can also get tularemia via the bite of an infected tick or deerfly, by eating contaminated food, by drinking contaminated water, or by breathing in F. tularensis, the bacteria that causes rabbit fever. However, tularemia doesn't spread from person to person, even in severe cases.
Symptoms of Rabbit Fever
The kind of disease one gets depends on how one is infected. With the skin form, Glickman says, a person usually gets a skin ulcer and swollen lymph glands. Those who eat or drink rabbit-fever germs get a very sore throat and, in more severe cases, ulcers in the mouth, diarrhea, and vomiting.
The inhaled form is most severe, with a 30% to 60% fatality rate in untreated cases. It causes pneumonia with sudden fever, chills, muscle and joint aches, dry cough, and progressive weakness. In severe cases there is bloody spit with difficulty breathing. And it's very infectious: As few as 10 microscopic germs can cause a lethal infection. This is why tularemia was studied during World War II as a germ warfare agent. Tularemia weapons were developed, but never used, during the Cold War.
If diagnosed early, rabbit fever is easily cured with antibiotic treatment. There's also a live vaccine, although it's not approved for public use. Given by inoculation -- much like the smallpox vaccine -- the vaccine is under the control of the U.S. Department of Defense. It was given to the U.S. by the Soviet Union in the midst of the Cold War.
Lawn Mowing and Rabbit Fever
The three Nebraska men developed the inhaled form of rabbit fever -- pneumonic tularemia. It wasn't bioterror. Two of the men were exposed when they ran over a nest of wild rabbits while mowing a lawn. The third man was exposed while cleaning the mower. All were treated with antibiotics and all recovered, the Associated Press reports.
It's not the first time people have come down with tularemia after mowing down bunnies. Lawn mowing was linked to a 2000 rabbit-fever outbreak in Martha's Vineyard. And in 1990 there was a report of two young boys who got the infection after accidentally killing a rabbit with a hand-pushed mower.
What About Pet Rabbits?
Unless they were caught in the wild, pet rabbits don't carry rabbit fever.
"In 25 years I have never seen or heard of a domestic bunny having tularemia," Glickman says. "But wild bunnies are another thing. That is always the risk when one rescues abandoned baby bunnies. And there are a few reported cases where cats have brought tularemia into the home after killing wild rabbits. Cats can spread the disease to humans, although this is more often a problem for veterinarians."
This doesn't mean you can't help a lost baby bunny. Just remember to wear gloves, Glickman advises. And don't bring the animal into the house. Keep it away from small children. Do not let the kids take it to school for show-and-tell. Instead, Glickman recommends, take it to the local Humane Society.