Wildlife Diseases

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Chronic Wasting Disease
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Wildlife Diseases
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Diseases Wildlife Get

Viruses, bacteria, fungi, and parasites are a normal and unavoidable part of the natural environment, so some disease is normal within a wildlife population. Usually diseases affect only a portion of animals and are not detrimental to a population, yet some diseases can spread widely and become a serious concern. MDC biologists watch for outbreaks of diseases that can harm wildlife populations as well as those that can be transmitted to humans, pets, and livestock.

Browse this section to learn about diseases that affect wildlife in Missouri and which ones can be harmful to humans and domestic animals.

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For your safety
  • Avoid handling sick or dead wildlife.
  • If you must handle a dead animal, always wear gloves and wash your hands after.
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Deer and Elk Diseases
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Liver abscess
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An abscess is a localized bacterial infection that often contains white, green, or yellow creamy material.

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Brainworm is caused by the parasitic roundworm Parelaphostrongylus tenuis.

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CWD is a slow-progressing disease affecting members of the deer family (cervids).

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These growths are variable in color, texture, number, and size (from a dime to a baseball), and often found around eyes and neck.

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Deer suffering from hair loss syndrome, credit Jeremy Holtzer
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Hair loss can be caused by a variety of bacteria, parasites, and fungi.

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Closeup of Hemal Nodes
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Hemal nodes are pea-sized spherical structures embedded within the fatty tissues of the body.

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Deer in pond.
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Biting midge flies in the genus Culicoides spread the viruses that cause this disease.

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Liver flukes
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Varying sizes of purple-gray, flat, oval parasites (flukes) may be seen in the liver.

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Adult female botflies eject developing larvae into the nostrils of deer.

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Deer with Seroma in the snow
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Yellow or reddish, clear fluid under skin or within muscle.

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Other Mammal Diseases
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Raccoons at water edge.
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Illness ranges from no symptoms to severe disease. Leptospirosis can be fatal if not treated.

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Raccoon with distemper
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Canine and feline distemper are caused by two different viruses that affect wild and domestic carnivores.

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Closeup of Hemal Nodes
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Hemal nodes are pea-sized spherical structures embedded within the fatty tissues of the body.

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Infected animal with cysticercosis
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Cysts, often resembling fluid-filled bladders, can appear on the surface of several organs in the abdomen as well as in the muscle tissue.

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Elk with mange grazing in snow
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Infected mammals show varying degrees of hair loss, usually on the legs and tail.

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Big brown bat on tree
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Rabies is a viral disease of mammals. Rabies testing requires brain tissue.

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RHDV2 is a highly contagious and potentially fatal disease for rabbits. It is a foreign animal disease and is of high concern in the United States.

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Closeup of raccoon intestine infected with raccoon ringworm
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The roundworm is called Baylisascaris procyonis. It is found primarily in raccoons.

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Closeup of intestine full of ringworms
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Roundworms are some of the most common worms found in wildlife worldwide.

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Tularemia is caused by a bacterium called Francisella tularensis

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Feral hog rooting in the woods
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Trichinosis is caused by a roundworm called Trichinella found in the muscles of infected animals.

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Bat with white fungus around nose
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Infected bats may exhibit white fungal growth on the muzzle and/or wings, and they often display abnormal behaviors in their hibernation sites during winter.

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Bird Diseases
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Bird infected with Aspergillosis
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Aspergillosis is a fungal infection caused by several Aspergillus species.

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Avian Pox In A Wild Turkey
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Avian pox is caused by a virus and has been shown to infect numerous species of birds worldwide.

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Symptoms of lead poisoning may include weakness, drooping wings, inability to fly, and green, watery diarrhea.

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This disease of wild turkey is so newly discovered that much remains unknown.

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Affected birds have cream-colored cysts resembling rice grains in the breast, heart, and leg muscles.

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Pigeons and doves are commonly infected, but they may not show clinical signs.

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Crow perched on tree branch
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WNV primarily infects and multiplies in birds, which serve as reservoirs (a persisting group of carriers) for the virus.

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Fish Diseases
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Fish with signs of columnaris
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The affected skin may have pale patches and/or a characteristic sore or lesion shaped like a saddle across the dorsal fin.

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Fluke larvae burrow into the flesh of the fish and form a cyst.

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Melanosis is not an infection but an increase in the melanin in the skin.

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Fish roundworms in body cavity of a fish
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Red, off-white, and white worms found under the skin, in the intestines, and in the body cavity.

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Sandy flesh shown in two filets
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The diseased flesh appears tough, granular, coarse, and yellow to brown, often resembling freezer-burned meat.

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Tapeworm larvae in fish cavity
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Tapeworm larvae (plerocercoids) often appear as white cysts or coiled worms in the flesh or internal organs

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Ulcers on the skin of a fish
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The most common causes are three bacteria in the genus Aeromonas.

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Numerous warts on the skin of a fish
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Fish have wartlike growths on the skin, fins, and occasionally gills.

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Water mold on skin of a catfish
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Water molds (which are not true molds or fungi) appear as white, gray, or tan cottony growths on the skin of the fish when submerged in water.