Rabbit Hunters Take Note: Steps to Avoid Tularemia
The Professor's Blog 02.25.13
Hello all, in the previous blog I indicated that I would talk about Toxoplasma gondii and Trichinella spp. in feral pigs. However, recently two rabbit hunters in eastern North Carolina tested positive for tularemia so I decided to address the current event first.
Rabbit hunting is a fantastic hunting experience and I fondly remember many days hunting rabbits with friends and family in northern Indiana. There are many reasons that I enjoy rabbit hunting. First, hunting rabbits can be as simple as walking a field, fencerow, or edge by yourself or with a friend or two. Second, you can wander through the field systematically or haphazardly. Third, you can increase the experience and excitement by working a thick briar patch with a pack of beagles and four or five close friends. Fourth, you can hunt rabbits anytime of the day–you do not have to get up at o’dark thirty. I am sure you have additional reasons that you enjoy rabbit hunting and I would love to hear them. Nevertheless, the excitement when a rabbit breaks cover is hard to beat.
Tularemia is often called rabbit fever, deer fly fever, meat-cutter’s disease, Ohara disease, and Francis disease. It is a zoonotic (can be passed from wildlife to humans) disease caused by the bacterium Francisella tularensis. Francisella tularensis naturally occurs in the environment, can survive in water and soil for weeks, and is common in rabbits, hares, and rodents. In fact, tularemia has been documented in over 150 wildlife species and is responsible for killing large numbers of wild animals. Tularemia occurs primarily in the Northern Hemisphere and has been reported throughout North America, Europe, Asia, northern Africa, and the Middle East, and recently a case was reported in Australia. In the United States, approximately 200 human cases are reported each year with reports from every state except Hawaii.
In rabbits, the symptoms include a white- or yellow-spotted liver and the liver and/or spleen may be a dark bluish-red and appear very swollen. Additionally, you may notice external ulcerations or infected areas where the animal was bitten by a tick or deer fly.
Humans most commonly become infected through skin contact with infected animals (e.g., rabbits), ticks, deer flies, bites from infected cats, eating improperly cooked meat, drinking contaminated water, or inhaling airborne bacteria. In the United States, rabbits are the source of infection in 90 percent of the cases, 70 percent of which comes from the cottontail rabbit genus Sylvilagus (16 species in this genus are recognized worldwide).
The incubation period for tularemia in humans is usually three to five days after exposure but can range from one to 14 days. The signs and symptoms depend on mode of exposure. Possible symptoms include skin ulcers and rashes, swollen and painful lymph nodes, inflamed eyes, sore throat, mouth sores, diarrhea, or pneumonia. If inhaled, symptoms can include fever, chills, headache, muscle aches, joint pain, dry cough, and progressive weakness. People with pneumonia can develop chest pain, difficulty breathing, bloody sputum, and respiratory failure. Tularemia can be fatal if not treated with appropriate antibiotics.
Last week, I provided some simple recommendations for hunters who clean feral pigs. Many of the recommendations are the same for rabbits. Hunters should always wear long sleeves, gloves, and eye protection when cleaning any game animal. After cleaning the animal, clean and disinfect all knives, clothing, or cleaning surfaces and absolutely make sure to wash your hands and forearms frequently and carefully with soap and water. Additionally, avoid drinking unfiltered or unclean water from streams and rivers. Insect repellents containing DEET have been shown to help prevent tularemia.
Hunters should avoid eating rabbits that appear in the field to be “lazy” or do not act “normal.” During the cleaning process, be sure to wear gloves, and hunters should examine the external surfaces of the rabbit for any infected areas. ALWAYS check the liver for the appearance of white or yellow spots. Even if the liver appears bright, does not have spots, and the rabbit appeared healthy in the field, make sure to cook the meat thoroughly; F. tularensis are killed by heat above 160 F.
As always, as long as these proper precautions are taken there is no reason not to enjoy your favorite fried or braised rabbit or hasenpfeffer.
I grew up in Michigan where I spent my early years hunting and fishing with family and friends and where I learned the intrinsic value of the outdoors and wildlife. While pursuing a graduate education in my twenties, I was fortunate enough to live in northern Indiana and western and eastern South Dakota where I took full advantage of the unique hunting and fishing opportunities in each state. After graduate school, my first job as a state wildlife biologist brought me to southern Minnesota where I immersed myself in the science of wildlife and habitat management and began to really appreciate the connections of research and management. In 2004, I moved my wife and two children to North Carolina where I have dedicated my career to mentoring the next generation of wildlife biologists and educating the general public about wildlife research and management.
The goals of my blog are to help connect all of you to the science of wildlife management. I plan to bring the latest scientific research to you in a casual, fun, and informative format. Everyone from the die-hard hunter, to the professional land manger, and the everyday homeowner encounters wildlife on a daily basis. Helping people understand the science behind wildlife management, the laws that govern wildlife and their habitats, the ways citizens can use research to enhance their land and hunting experience, and dispelling the myths that surround wildlife, while fostering an appreciation for the natural world are my passions. Hopefully, that will come across in my posts and I encourage everyone to take advantage of the special question and answer section where I will do my best to offer you the latest scientific research to help enhance your enjoyment of the natural world.
Credentials
I earned a Bachelor of Science from Central Michigan University (1990), a Master of Science in Behavioral Ecology from Purdue University (1994), and a Ph.D. in Wildlife Management from South Dakota State University (1998). From 1999-2004, I worked as a research scientist for the Minnesota Department of Natural Resources. Since 2004, I have been a professor in the Fisheries, Wildlife, and Conservation Biology Program at North Carolina State University (NCSU) where my research interests include population ecology, habitat use and management of big game species and predators, predator/prey interactions, human/wildlife interaction, and wildlife and zoonotic diseases. Specifically, I have conducted research on white-tailed deer, coyotes, feral pigs, American woodcock, fox squirrels, wild turkey, Canada geese, river otters, amphibians, and reptiles, and other species.
I am a member of The Wildlife Society, American Society of Mammalogists, Great Plains Natural Science Society, Jack H. Berryman Institute, Scientific Advisory Panel, North Carolina Prescribed Fire Council, and the North Carolina Herpetological Society. In 2002, I became a ‘Certified Wildlife Biologist’ via The Wildlife Society. I have served as an Associate Editor of the Prairie Naturalist and the Proceedings of the Southeastern Association of Fish and Wildlife Agencies. Additionally, I am past-President of the Great Plains Natural Science Society and the North Carolina Chapter of The Wildlife Society.
