(Other names: Avian diphtheria, bird pox, fowl pox)
Turkey with signs of severe avian pox.
Credit: Michigan Department of Natural Resources, Wildlife Disease Lab
Description
Avian pox is a slow-progressing disease in birds that is caused by viral species in the genus Avipoxvirus. This group of viruses have been found to cause disease in at least 232 bird species. There are several different types of avian pox viruses that cause disease. Most only infect a particular species of bird. Wild bird species most often affected include turkeys, raptors, owls, doves, and sparrows.
Transmission
Avian pox viruses can remain viable outside of a host for a long time. Transmission routes for wild birds tend to occur in three ways: bird-to-bird contact (e.g., mating, fighting), indirect contact (e.g., contaminated bird feeders), and through a biting insect (fleas, mosquitoes, midges, mites, etc.).
Clinical Signs
Avian pox occurs in one of two forms: a diphtheritic form (wet pox) and a cutaneous form (dry pox). Signs of wet pox include lesions in the upper respiratory tract and gastrointestinal lining of the birds. This condition can lead to general weakness, emaciation, and difficulty eating and breathing, and it can eventually lead to death.
Dry pox on wild birds causes wartlike growths on unfeathered areas of the bird, such as around the eyes, beaks, and legs. Growths typically persist for one to four weeks and may leave long-lasting scars; however, all clinical signs vary depending on the bird species, the severity of the avipoxviruses, and other complex factors.
Wildlife Management Implications
Avian pox is not generally a management concern in Indiana because it does not significantly affect bird populations in the state, but individual birds are often affected.
There are several actions you can take to help prevent transmission of avian pox in wild birds:
- Routinely clean bird feeders and bird baths with a 10% bleach solution (i.e., 1 cup of bleach mixed with 9 cups of water).
- Remove standing water on your property to reduce mosquito activity.
- If you encounter a wild bird with signs of avian pox, submit a Sick or Dead Wildlife Report to the Indiana DNR. Your reports help us track and mitigate potential disease outbreaks.
Human Health Significance
Avian pox has no noted effects on humans; however, always take a precautionary approach when removing a dead bird from your property. Wear gloves, seal the bird in a plastic bag, and put it in a secure garbage receptacle.
Additional Resources
Cornell University College of Veterinary Medicine
PennVet Wildlife Futures Program
Northeast Wildlife Disease Cooperative
Hansen, W. (1999). Avian pox (No. 1999-0001, pp. 163-169). US Geological Survey.