Recognizing and Understanding Wild Turkey Diseases
It’s fairly uncommon to tag or observe a wild turkey that shows signs of infection or disease, but it does happen. Overall, America’s favorite game bird continues to survive challenges as it has for eons. But there are some fowl diseases—bacterial and viral infections, and parasites that affect turkeys. As responsible hunters and gamekeepers, we can help turkeys by being vigilant for birds that appear ill, whether we’re observing them or admiring one up close after a successful hunt. Wild turkey diseases such as avian pox and LPDV (lymphoproliferative disease) can impact populations, making it important to recognize symptoms and report sick birds.
The spring column will focus on avian pox and LPDV (lymphoproliferative disease). What are these diseases, their symptoms, and how do we report sick birds? These questions and others are answered by wild turkey expert and researcher, Dr. Michael J. Chamberlain, PhD., Terrell Distinguished Professor of Wildlife Ecology and Management at Warnell School of Forestry and Natural Resources at the University of Georgia.
Avian Pox: The Most Common Disease in Wild Turkeys
Tes Jolly
Avian pox occurs worldwide in over 200 bird species, including domestic poultry. It’s reported less in raptors and rarely in waterfowl. Extensive research shows it’s the most common disease affecting wild turkeys.
Various strains of avipoxvirus cause this highly contagious, infectious disease. Transmission occurs primarily via biting insects like mosquitos or direct contact with an infected bird. It may also be ingested through contaminated food or water. Transmission via contaminated dust by inhalation may occur at wildlife feeder locations where turkeys repeatedly congregate. The disease is more common during warm months and in the South. Research shows wild turkeys have not been linked to outbreaks in domestic poultry.
Are There Different Types of Avian Pox Disease in Wild Turkeys?
Tes Jolly
Dr. Chamberlain: “There are two forms of avian pox, one that causes lesions on the head and neck and a second that causes lesions in the respiratory tract. Many birds will carry the virus and exhibit lesions on the head, neck, and legs but survive the virus. However, birds that end up with lesions in the respiratory tract have higher mortality rates as they may have compromised abilities to eat and breathe.”
What Are the Physical and Behavioral Signs of Avian Pox? Is It Transmissible to Humans?
Dr. Chamberlain: “The presence of lesions on the head, neck, and legs is a sign that the bird may be suffering from avian pox. Birds that have lesions in the respiratory system may appear lethargic and emaciated, and birds with severe lesions on the head where vision is compromised may act confused. The virus is not transmissible to humans.”
Are There Regional or Seasonal Trends for Avian Pox? Does It Impact Turkey Populations?
Dr. Chamberlain: “Avian pox appears in many populations and is reported throughout the species range annually. However, given that the virus is spread by biting insects, it’s logical to expect the disease to be more common where such insects are common. There is no evidence that avian pox results in any substantive impacts to turkey populations despite the fact that the virus does cause mortalities in some birds.”
LPDV (Lymphoproliferative Disease) in Wild Turkeys
Tes Jolly
LPDV has been known to occur in domestic turkeys in Europe and Israel since the 1970s. In 2009, the first documented case in North America was made in a wild turkey from Arkansas that had lymphoid tumors. Since then, LPDV has been observed in more than two dozen states and Canada.
Transmission occurs by direct contact with an infected bird. Ongoing work at Southeastern Cooperative Wildlife Disease Study (SCWDS) shows that it can also be spread by biting insects. The disease is caused by a retrovirus that’s capable of causing cancerous tumors in the head, neck, and organs. Dry, crusty lesions similar to those seen in avian pox may form on featherless body parts. Infected birds may experience lethargy, weakness, a compromised immune system, and other diseases such as bacterial infections or avian pox.
How Common Is LPDV in Wild Turkey Populations?
Tes Jolly
Dr. Chamberlain: “Ongoing work shows that occurrence varies considerably across populations, with some populations showing a 75% prevalence whereas others nearby show ~30%. Based on our work across the Southeast, it does appear that the virus is present in all populations at some prevalence exceeding 25%.”
What Are the Defining Clinical Signs in a Lab Diagnosis?
Dr. Chamberlain: “LPDV causes tumors in a number of organs, so in a lab diagnosis, tumors in the spleen, pancreas, and liver are often the defining clinical signs.”
What Is the Mortality Rate in Turkeys Infected with LPDV? Does It Impact Reproduction?
Dr. Chamberlain: “The mortality rate that LPDV has is unclear, as it appears that in many populations (as noted above) the prevalence rate is quite high but most birds are surviving the virus. Whether the virus impacts reproduction is also unclear, but is currently being studied throughout portions of the country.”
Does LPDV Share Similar Symptoms with Avian Pox? Is It Transmissible to Humans?
Tes Jolly
Dr. Chamberlain: “As for outward signs, infected birds will sometimes have lesions on the head and neck similar to avian pox, and there’s evidence that LPDV is often present with avian pox. The virus seems to be limited to turkeys and chickens.”
Conclusion: The Role of Hunters and Gamekeepers
The flocking nature of turkeys can be a risk factor in disease spread. As responsible gamekeepers who love this special wildlife resource, our thoughtful consideration is in order for the best methods of supplemental feeding that may potentially gather birds repeatedly in close proximity.
Ongoing disease studies are being supported and assisted in funding by Mossy Oak , state wildlife agencies, universities, conservation organizations and associations like Turkeys for Tomorrow, the National Wild Turkey Federation, hunters, landowners, and others.
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