Rabbit season — which began in Missouri on October 1 — is easily the year’s least heralded opening day. On the surface that seems odd, because rabbits are one of the state’s most popular small game animals.
Part of the problem this year is that the first couple of weeks of October have simply been too warm for beagles to chase bunnies or for humans to stomp brush piles. Even so, the real reason there’s so little interest in early season rabbit hunting in Missouri is a generations-old belief that rabbits aren’t safe to eat either until after the first hard freeze or after the first snowfall. The theory behind this fable is that the additional stress brought on by cold weather or snow cover will kill all of the “sick” rabbits.
Rabbits can indeed be carriers of a potentially disabling or even fatal disease that also affects humans. That disease is tularemia — a.k.a. rabbit fever, deer fly fever, Pahvant Valley Plague and O’Hara’s fever. Tularemia is caused by a bacterium that can be transmitted to humans in several ways. Ticks, deer flies and fleas are the primary rabbit-to-rabbit vectors and are often the source of human infections. Direct rabbit-to-human transfer can occur through handling infected rabbits, through inhaling bacteria present in the fur of infected rabbits and through eating the meat of infected rabbits. (Note: Thorough cooking destroys the bacterium.)
Tularemia is a serious disease. In the 4th century BC, It became the first organism known to have been used in biological warfare. Enhanced strains of the tularemia bacterium have been developed for modern biological warfare use, ironically because the organism is highly incapacitating but seldom lethal.
Delaying rabbit hunting is pointless, because there is no tularemia-free time of the year. While there’s no certain way to identify a live rabbit that’s infected with tularaemia, infected rabbits act sick and may be unwary or unable to run normally. In addition, the liver of a tularemia-infected rabbit will display many tiny white spots and may be swollen.
I assume any rabbit that can stay ahead of my beagles for an extended period of time is probably — and I stress probably — safe to eat. Even so, I always wear disposable vinyl gloves when cleaning any species of fish or game. Admittedly, my primary goal is to keep my hands clean, but wearing gloves is also an excellent first line of defense against exposure to either diseases or parasites. When I plan to clean my game in the field — which is most of the time — I carry soap and water or antibacterial wipes to thoroughly clean up after removing the gloves.
While I firmly believe in being cautious, I’m also aware of the fact that tularemia is very rare in the United States. The Center for Disease Control records less than 300 cases per year, and Kenneth C. Sadler, the Missouri Department of Conservation’s rabbit guru, has seen only two infected rabbits during the course of 20 years of extensive field research.
Missouri rabbit hunters occasionally find threadlike whitish streaks parallel to the muscle fibers in cleaned rabbits. These are the cysts of a parasite of the genus Sarcocystis. There is general scientific agreement that rabbits are an intermediate host for a species of Sarcocystis with cats as a final host. Humans are the final host for a species that occurs in cattle and swine, but there is no evidence of a rabbit/human connection. Even so, any hunter who decides to discard a rabbit infected with Sarcocystis won’t hear any criticism from me.
Oddly enough, some of the most horrible looking rabbit parasites are the most benign both to their host and to humans. Bladderworms are a case in point. Bladderworms, which are the intermediate stage of the canine tapeworm, form nearly clear, jelly-like cysts that attach themselves throughout the visceral cavity and may cause a small number of readily visible white spots on the liver. Bladderworms are very species-specific and pose no threat to humans.
Another species of tapeworm reaches the adult stage in the rabbit’s intestinal tract. This particular tapeworm can survive only in rabbits and poses no threat to humans.
The larval stage of a large species of bot fly may well be the most repulsive rabbit parasite. Also known as warbles, grubs or wolves, these larvae, which are often more than an inch long, lie just under the host rabbit’s skin. They emerge in mid- to late October and drop to the ground to pupate. They do no harm to their host and pose no threat to humans.
If you’re interested in reading more about this subject, I recommend “Common Diseases and Parasites of Cottontails” by Kenneth C. Sadler. It’s available on the MDC website.
Gerald Scott can be reached at [email protected]