The camouflaged hazards of hunting

Taking down large game can be the thrill of a lifetime for an outdoorsperson, but anyone who wields a weapon in the act of hunting should be cognizant of basic food safety and the diseases, parasites and bacteria that share the great outdoors. Jerry Shaw, programs supervisor for the Oklahoma Department of Wildlife Conservation, said although there are not too many wildlife diseases in his state that are of major concern, but all hunters need to be able to recognize the signs of sick animals and follow proper rules for food safety.

“One of the main diseases we are always on the lookout for is chronic wasting disease,” Shaw said. “It has not ever been shown to be transmissible to humans, but just as a protection to the resources, we want to make sure that we’re not taking deer that are CWD-positive and moving to other locations and leaving the bones and carcass where the disease can be spread to other deer.”

Shaw noted that internal and external parasites are often considered a bigger risk than disease in game animals.

“Most often if a deer has a disease, it’s either not going to be transmissible to humans or the animal is going to appear sick and therefore not as likely to be shot by a hunter,” he said.

Once an animal is killed and a hunter begins the field dressing process, there are certain signs that indicate the animal could harbor a disease or parasite. Shaw said one of the major symptoms or disease is internal abscesses when the animal is opened up.

“Additionally, anytime you notice meat that is an off color, it’s a bad sign,” he explained. “There are some diseases, especially if an animal becomes septic, that the meat will take on a green or gray tint. Also, if you notice a deer has staining around the rump from where it has been incontinent or has had scours it could likely be an indicator of sickness too. Anytime you see those things you should get in touch with a local wildlife department employee.”

The American Veterinary Medical Association recommends hunters minimize contact with brain or spinal tissues while boning out the carcass, keep both the head and spine intact. Hunters should never cut into the head of any antlered animal that showed abnormal behavior, even to remove the rack.

“We always recommend folks wear gloves when they’re field dressing deer and follow safe food handling practices and cook meat thoroughly,” Shaw added.

The AVMA advises if any of the intestines have an abnormal smell or discharge, or if pockets of blood are seen in the muscle not resulting from the bullet or arrow wound, the meat should be discarded. Additionally, any area of the carcass with old wounds, and especially if there is pus present, should not be consumed. A large area of tissue around the wound and pus pockets should also be cut away with the wound, even if the tissue looks normal, because it can still contain infection.

Hunters should avoid abdominal shots because they can lead to contamination of the meat. If any intestinal contents of the animal come in contact with meat, it should be considered contaminated. Do not feed the contaminated meat to other animals, or they may become ill.

“Always thoroughly clean carcasses and get it cooled down as quickly as possible, not only does it lend to proper food safety, but also just makes for a better product,” Shaw said. “If you have a lot of blood-shot meat in the area around the arrow or bullet wound, you should trim that away as quickly as possible because that will start to spoil before the rest of the tissue.”

Diseases and conditions to watch out for

Anaplasmosis is a tick-borne disease caused by the Anaplasma phagocytophilum bacteria. It is spread by tick bites, primarily by the blacklegged and western blacklegged ticks. According to the AVMA, the majority of the cases were reported in the eastern and central United States.

Brucellosis is most commonly caused by the Brucella abortus or the Brucella suis bacteria. Bison, elk, reindeer and caribou can become infected with the bacteria and develop brucellosis, but their part in spreading the infections to livestock remains unclear. Brucellosis is a serious diseases of livestock and causes substantial economic losses in production, and can be contracted by people. According to AVMA, there is a possibility that disease organisms could be transmitted from infected animals to humans, so hunters should take precautions around animals during the cleaning process, specifically feral hogs.

Chronic wasting disease is a transmissible spongiform encephalopathy, in the same class of diseases as bovine spongiform encephalopathy, commonly known as mad cow disease. These diseases are caused by prions, which are infectious proteins. The diseases affect the brain and spinal cord, causing signs such as weakness, incoordination and abnormal behavior. AMVA indicates it is not fully understood how CWD is spread from animal to animal, but it is believed to be transmitted through direct animal-to-animal contact or when an animal eats soil contaminated by saliva or feces from an infected animal. Only four species are known to be naturally susceptible to CWD: mule deer, white-tailed deer, Shiras moose and Rocky Mountain elk. Signs of a possibly infected animal include stumbling, lowered head, droopy ears, weakness, a wide stance, excessive salivation and emaciation. There is no current evidence that CWD passes to humans.

Trichinellosis, also called trichinosis, is caused by a parasite called Trichinella spiralis. Unlike many other parasites that can infect people, this parasite lives in the muscle tissue of animals. Because the meat of the animal is actually its muscle tissue, the parasite can infect people who eat the meat of an infected animal. In North America, it is common in the cougar and the grizzly bear but has also been reported in black bear, wolf, red fox, coyote, lynx and feral hogs. Although it is considered to be a relatively minor disease in wildlife, causing minimal behavioral changes—such as less activity, increased predation and decreased reproductive activity—trichinellosis can be fatal in humans. As the parasites burrow into the muscle cells, the muscle cells in effect shelter the larvae and can live for years in an animal. They only come out of dormancy when the meat they have been living in is eaten by a carnivore. The onset of illness depends on the number of parasites and the amount of meat eaten.

Deer Parapoxvirus has been reported in red deer in New Zealand, but human infections have occurred in the U.S. The virus is related to the orf virus, which affects sheep and goats, and the Pseudocowpox virus, which affects cattle. The deer parapoxvirus causes scabby, crusty lesions on the muzzle, lips, face, ears, neck and antlers of affected deer.

West Nile virus is carried by mosquitos and has been in the U.S. since the late 1990s. The virus infects wild birds and mosquitoes then transfers the virus to other animals and humans. Sudden bird deaths can indicate the presence of West Nile virus in the area. Hunters should avoid handling dead birds they encounter that have not been shot during the hunt.

Equine encephalitis viruses, including the Eastern equine encephalitis virus, Western equine encephalitis virus and Venezuelan equine encephalitis virus are transmitted by mosquitoes. Just like West Nile Virus, the primary hosts for the encephalitis viruses are wild birds.

Escherichia coli infection, or E. coli, is a bacteria that causes diarrhea and stomach pain in humans and can cause death. Although most cases of E. coli infection come from eating contaminated beef or drinking unpasteurized, contaminated milk, it is possible for white-tailed deer to become infected when they graze in cow pastures contaminated with the bacteria. According to AVMA, disease-causing E. coli has been found in cattle, goats, sheep, deer, elk, pigs and birds. Because the bacteria live in the animal’s intestines, shooting a deer through its abdomen can increase the risk of contamination of the muscle by the intestinal fluids. The risk of infection is also related to how the carcass is handled, dressed, processed, preserved, stored and cooked.

Tuberculosis Mycobacterium bovis, a bacteria, causes bovine tuberculosis. However, this is a different disease and bacteria than human tuberculosis. M. bovis infection has been reported in wild hogs, white-tailed deer, mule deer, elk, bison, badgers, possums, water buffalo, wapiti and other species. M. bovis poses a minimal risk to people, but can easily infect domestic cattle herds. When field dressing an elk or deer, hunters should look for tan or yellow pea-sized lumps in the wall of the rib cage or in the lungs. If these lumps are present, the hunter should immediately stop handling the carcass, attach a game tag, and contact the local fish and wildlife agency.

Lyme Disease, or Lyme borreliosis, is an illness caused by a bacterium, Borrelia burgdorferi. Deer ticks are the primary carriers of the bacteria. In humans, often the earliest indication of infection is a "bullseye" rash at the site of the tick bite. The disease can progress to cause chronic joint problems as well as heart and neurological problems. Lyme disease is not contagious from one person to another.

Plague is a disease caused by infection with Yersinia pestis bacteria, the same bacteria responsible for the "Black Death" that killed millions of people in the 1300s. The bacteria are still present in the environment in several regions of the nation, and the disease has recently been reported in mountain lions, rodents, rabbits, squirrels and other carnivorous animals. Plague can be transmitted to hunters through bites of infected fleas or by direct contact with infected animal tissues when skinning or handling wild game. The highest risks of exposures come from infected blood and tissues. The disease is more commonly found in areas with high populations of prairie dogs or other rodents.

Q fever is a disease caused by the Coxiella burnetii bacteria. Cattle, sheep and goats are the primary carriers of C. burnetii, but cats, dogs, some wild mammals, birds and ticks are also natural hosts. The bacteria can be present in high numbers in the birth tissues of infected animals. The nesting sites of infected animals pose a high risk for infection. The bacteria most often infects humans and animals through the air. Hunters can become infected with Q fever and it is often mistaken for a flu or cold. Many animals do not exhibit signs of the disease, but infected dogs can shed the bacteria in their urine or milk and serve as sources of infection of their owners.

Rabies is caused by different variants of the rabies virus. The virus is transmitted primarily through bites and causes severe damage to the brain. The AVMA indicates non-bite transmission of the rabies virus is extremely rare, but can occur through scratches, abrasions, open wounds or mucous membranes contaminated with saliva or other potentially infectious material—such as brain tissue—from a rabid animal. The virus can infect any mammal, but it is most common in raccoons, foxes, skunks and bats. Once clinical signs of rabies are observed, it is 100% fatal in animals and almost 100% fatal in humans.

Rocky Mountain Spotted Fever is caused by the Rickettsia rickettsii bacteria and can be transmitted to hunters via tick bites. RMSF cannot be transmitted from person to person.

Salmonellosis is a bacterial infection caused by Salmonella species. There are many Salmonella species that can cause infection and illness. Many species of animals, including pets, livestock, reptiles, birds and wildlife, can be infected and can spread Salmonella. These bacteria usually infect the intestinal tract but also can be found in urine, blood or in other body tissues. Salmonella bacteria spreads through fecal-oral transmission.

Lacey Newlin can be reached at 620-227-1871 or [email protected].