Wildlife Diseases, Parasites, and Infections

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Bird Infections, Diseases & Parasites

While most bird infections, diseases, and parasites are difficult to identify without testing, finding a dead bird often is not a cause for concern. Birds occasionally run into windows, die from natural causes, or may succumb to the elements. If you find an aggregation of five or more dead birds, that may represent an illness among a population. If you find this, please contact a regional wildlife biologist and report your findings.

To help prevent the spread of various bird illnesses, clean your bird feeders regularly, removing old seeds and cleaning any debris and bird droppings. After cleaning, soak the feeder in a bleach and water solution for fifteen minutes, rinse and allow to dry before refilling with seed. If you want to attract birds without feeders, plant certain species of bushes and trees near your home, allowing a natural, clean and healthy environment for birds to use.

Avian Conjunctivitis

Avian conjunctivitis is a bacterial eye infection in birds that often impact many species of songbirds. The bacteria cause the tissue around the eye to swell, becoming red and irritated. If the infection is severe, it will continue to spread and can often cause the bird to become completely blind. Avian conjunctivitis is most common during summer months, where the bacteria can easily spread between bird feeders simply by an infected bird visiting the feeder.

Avian Pox

Avian pox is an infectious disease of birds, commonly transmitted through biting insects such as mosquitos, fleas, flies, and midges. Transmission occurs most often during warmer months when biting insects are ample. Transmission can also occur through direct contact with another infected bird by contaminated surfaces and objects, such as bird feeders. Avian pox causes wart-like growth on skin, especially on unfeathered parts of the body. In most cases, the bird will survive, and the warts will heal with time, however, in severe cases, more severe lesions can develop and sometimes lead to death. Turkeys are often reported with pox lesions causing blindness.

Avian Malaria

Avian Malaria is a single-celled protozoan that is transmitted through the bite of infected mosquitoes. It affects a wide variety of birds globally and can cause significant impacts to bird populations where there was no prior exposure and species had little opportunity to evolve defenses. While the majority of bird species don’t die from avian malaria, it can lead to chronic side effects and shorter lifespans (Audubon). As our climate continues to climb, malaria-carrying mosquitoes are expanding their range, possibly leading to greater impact on bird populations locally and globally.

Avian Influenza

Avian Influenza (AI) is a type A influenza virus naturally found in certain waterfowl and shorebird species. AI refers to the disease caused by infection with avian influenza Type A viruses. These viruses occur naturally among wild aquatic birds worldwide and can infect domestic poultry and other bird and animal species, but rarely infect humans. Avian influenza can be spread through saliva, nasal secretions, and feces directly from an infected bird or through contaminated surfaces. If a person contracts the avian influenza, they can experience a wide range of flu-like symptoms, though laboratory testing is needed to confirm the diagnoses. Learn more about Avian Influenza.

Avian Cholera

Avian Cholera is a contagious bacterial disease that affects ducks, geese, coots, gulls, and crows.
It can be transmitted by bird-to-bird contact, contact with secretions or feces of infected birds, or through food, water, and soil. It is deadly to birds, but not considered contagious to humans. Avian Cholera can cause thousands of deaths in wild waterfowl in North America during outbreaks. The bacteria cause hemorrhaging on the heart muscle and gizzard, causing very sudden death.

Wellfleet Bay Virus

The Wellfleet Bay virus is a disease that affects the Eider ducks and has thus far been confined to one location: Wellfleet, Massachusetts. Loosely related to the flu virus, it attacks the liver and gallbladder, and seems to work very fast. Transmission is not yet fully understood. Learn more at NWDC.

Lymphoproliferative Disease Virus (LPDV)

LPDV is a disease that affects turkeys and was not detected in the United States until 2012, though it had been seen in domestic turkeys in Great Britain. The disease is similar to Avian Pox and manifests as tumors to the head and feet of turkey, but it is not transmissible to humans. Transmission is believed to occur between birds that have had direct contact.

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Deer Diseases, Parasites, and Infections

Chronic Wasting Disease (CWD)

Chronic Wasting Disease (CWD) is a fatal disease that affects cervids such as deer and moose. It has not yet been found in Maine, and there are things hunters can do to prevent it from being spread here. Learn more by visiting our CWD page.

Epizootic Hemorrhagic Disease (EHD) and Bluetongue Virus (BT)

Epizootic Hemorrhagic Disease (EHD) as well as Bluetongue Virus (BT) are illnesses caused by two similar viruses impacting white-tailed deer with EHD being more common in deer. These viruses are transmitted by the biting midge, Culicoides. Learn more about Epizootic Hemorrhagic Disease and Bluetongue Virus.


Deer fibromas are wart-like growths on deer that are typically caused by an infection with a species-specific papillomavirus. In most cases, fibromas will not negatively impact the health of infected deer, and fibromas are not known to be a significant source of deer mortality. Learn more on our deer fibroma page.

Lice, mange, and/or dermatophilosis

It is not uncommon to see deer missing patches of fur, and there are several possible causes for this including lice, mange, and/or dermatophilosis, also known as rain rot. Learn more on our hair loss in deer page.

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Small Mammal Infections, Diseases, and Parasites


Rabies is a virus that infects the central nervous system of mammals (most commonly bats, fox, raccoons, and skunk), causing a brain disease that is fatal unless treated before symptoms start. It is spread by direct contact through a scratch or bite that breaks the skin, or through a mucous membrane. Learn more about rabies.


Mange is a contagious skin disease that is caused by mites. Mange results in hair loss and is most commonly seen in foxes and coyotes in Maine, but has also been reported in bobcats, black bears, porcupines, rabbits, squirrels, and raccoons in other areas of North America. People can be infected with mange, a condition known as scabies. If you see a wild animal with mange, there is no need to call for help. Many affected animals with mange are able to recover from the disease. Mange is a naturally occurring disease that helps manage wildlife populations at healthy levels. Learn more at NWDC (PDF).

White-nose Syndrome

White-nose syndrome is a deadly disease that affects bats that hibernate in the winter. It is called white-nose syndrome because of the white fungus commonly found on the muzzles of infected bats. WNS emerged in Maine in 2011 and affects several native bat species. Learn more about white-nose syndrome.


Large accumulations of bat droppings may harbor histoplasmosis fungi spores, which when inhaled can result in a lung infection referred to as "histo." No histo cases have been reported in Maine, but precautions should be followed when cleaning or removing large accumulations of bat droppings. Call your local health department for recommendations.

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Moose Infections, Diseases, and Parasites

Winter Tick

The winter tick is a small, external parasite which, like all of Maine’s 15 tick species, survives on the blood of animals. Unlike other ticks, winter ticks are not known to spread disease. However, they can be deadly to moose. Learn more on our winter tick page.

Brain Worm

Brain worm is a parasitic nematode (round worm) called Parelaphostrongylus tenuis. White-tailed deer are the common host for brain worm, typically without negative impacts to the deer. However, other species such as moose, are hosts that often develop severe neurological deficits, abnormal behavior, and often die after a period of infection. Common signs and symptoms of a moose that is infected with Brainworm is loss of voluntary muscle control, listlessness and general weakness, fearlessness, circling behavior, head tilting, emaciation and paralysis . If you notice possible symptoms of brain worm, please contact a local game warden.

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Amphibian & Reptile Infections, Diseases, and Parasites

Chytrid Fungus

Chytridiomycosis (Chytrid) is an infectious disease caused by an aquatic fungal pathogen that has led to devasting declines in amphibian populations, mainly frogs and toads, around the world in the last 30 years. It is believed that chytrid fungus continues to spread through the amphibian trade for pets and human consumption, mainly by bullfrogs, and the fungus has been documented in several species of amphibians in Maine. The pathogen attaches to the keratinized portions of an amphibian and reproduces, eventually leading to degradation of the skin, weight loss and often death. Because frogs and salamander’s breath through their skin (cutaneous respiration), damage and disruption of skin function is sometimes lethal. To help prevent the spread chytrid fungus, do not release unwanted reptiles or amphibians, especially those imported from out of state, into Maine’s environment without first contacting MDIFW for guidance.


Batrachochytrium salamandrivorans (Bsal) is a fungal pathogen that is likely endemic to Asia but has spread through the global pet trade and primarily infects newts and salamanders, leading to a fatal skin disease in non-resistant species. While Bsal has not yet reached North America, it could be just one “shipment” away from arrival, and preventing this fungal pathogen is imperative to maintaining a healthy diversity of amphibians. Monitoring for the presence of Bsal in North American salamander populations is critical for developing rapid quarantine and control measures if detected. The NWHC is working with the EDGS Amphibian Research and Monitoring Initiative to reach a goal of 10,000 samples in high-risk areas (USGS). Do not release unwanted reptiles or amphibians, especially those imported from out of state, into Maine’s environment without first contacting MDIFW for guidance.


Ranavirus causes severe infections in amphibians, reptiles and fish with a mortality rate of 90-100% and a global distribution on five continents. Transmission of Ranavirus occurs through direct contact, ingestion of the virus, ingestion of infected animals, or exposure to contaminated soil or water. While scientists are still identifying likely methods of transfer, it is believed the virus is temperature and density dependent, peaking during summer months with high air temperatures and large numbers of frogs in and around ponds.

Snake Fungal Disease

Snake fungal disease is an infectious disease caused by the fungus Ophidiomyces ophiodiicola and has been detected in at least 38 states. While severity of the infection may vary from species to species, sign of this fungus may include localized thickening or crusting of the skin, bumps under the skin, abnormal molting, cloudiness of the eyes, and facial disfiguration leading to emaciation and death. Transmission is not well understood, though it’s thought to survive in the environment where snakes may come into direct contact with it.


Salmonella is a name for an entire family of bacterial that live in the intestines of humans or animals and are shed in the stool. While salmonella is well known for causing infections through contaminated food, you can also get infected by handling reptiles and amphibians or droppings existing in your environment. Ensure you always wash your hands thoroughly after handling reptiles and amphibians or anything in the area they live or roam. Do not catch and keep wild reptiles or amphibians and do not release unwanted reptiles or amphibians into the environment.

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