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Common rabbit and hare afflictions
Shope fibromas are gray, black, and white wart-like growths that occur on the face, ears, or feet of cottontail rabbits. They are caused by a virus transmitted through biting insects. Fibromas are usually small (maximum 25 mm diameter) and are few in number. The growths may remain for 10 to 14 months and can then spontaneously regress. Fibromas generally do not cause harm to the animal and they only involve the skin, therefore the meat of the animal is edible.
External parasites can occur on the carcasses of rabbits and hares. Ticks are normally found on the head and ears and fleas can be found over the entire body. These parasites usually do not cause any harm to the animal unless they oc-cur in large numbers. External parasites will leave the host after it dies.
Warbles are the larval stage of the botfly (Cuterebra sp.). They usually live within the skin and subcutaneous space of the neck and throat area of the cottontail rabbit. The larvae complete their development in this space, changing color from white to black and reaching sizes of ½ inch x 1 inch. Warbles are normally present in the rabbit during the summer months but it is possible for some to remain during the early portion of the hunting season. It is possible for the warble to have a debilitating and fatal effect on the rabbit. Humans can’t be infected with the lar-vae so the carcass is edible.
Sarcocystosis is a disease of cottontail rabbits caused by the protozoan parasite Sarcocystis cuniculi. The sarcocyst appears as an elongate white strand within the musculature of the legs. Unlike sarcocystosis in waterfowl, sarcocystosis in rabbits does affect the animal’s behavior due to a weakening of the musculature. These animals are lethargic and could be easily preyed upon by predators or easily harvested. It is unlikely that humans could be infected by ingesting the cysts, but it is recommend-ed that the carcass be disposed of and not consumed.
Cysticerci (cysts) of the tapeworm Multiceps serialis occur occa-sionally in snowshoe hares and rarely in cottontail rabbits and are found be-tween the muscle layers of the rear legs. These cysts occur in clusters (grape-like), are fairly large and elon-gate, and contain clear liquid and sever-al white floating objects (the heads of the tapeworms). The cysts resemble blisters, which is a common name for them. Humans can’t be infected by han-dling or consuming an infected carcass so the meat is edible.
Cysticerci (cysts) of the tapeworm Taenia pisiformis occur in cottontail rabbits usually attached to the surface of the liver and the intestines and occasionally on the lungs. These cysts occur singly, are 5 to 7 mm in diameter, and contain clear liquid and a single white floating object (head of the tapeworm). The cysts are normally removed when the animal is field dressed, and any that might be missed would be killed in the cooking process. Humans can’t be infected by handling or consuming an infected carcass so the meat is edible.
Liver and spleen
Tularemia is a bacterial infection caused by the bacterium Francisella tularensis and the terrestrial form of the disease has been diagnosed in rabbits and snowshoe hares. Small white necrotic foci (pimple-like in appearance) are observed on and in the liver and the spleen. The disease does cause the rabbit to act lethargic or sick. Humans can contract the disease via contamination with blood or by ingesting insufficiently-cooked Infected carcasses. Rabbits that display liver and spleen lesions consistent with the above description should be collected and submitted to the Lab for examination.
Rabbit Hemorrhagic Disease Virus 2 (RHDV2)
Rabbit Hemorrhagic Disease Virus 2 is a highly contagious and fatal calicivirus that affects Lagomorphs (domestic and wild rabbits, hares, and pikas). In Michigan, this includes cottontail rabbits and snowshoe hares. It’s been found in wild populations in 14 states, but has not been found in Michigan. The virus attacks the internal organs and causes hemorrhaging, leading the affected animal to bleed out. Sudden death in otherwise healthy rabbit populations is usually observed, along with blood around the mouth and nostrils of dead specimens. If a wild rabbit or hare is found dead with blood around their nose and mouth, and no obvious cause of death, it should be collected and submitted to the Lab for testing.