This Turkey Tuesday is about avian pox, which is the most common disease affecting wild turkeys. Avian pox is caused by a strain of avipoxvirus and there are 2 forms of the disease that include a dry and wet form. The wet form affects the bird’s mucous membranes in the upper respiratory and gastrointestinal systems, but the dry form is what most of us see when we encounter birds suffering from avian pox. That is, infected birds with wart-like growths on the head, neck, and legs. In some cases, a bird may only have a few small lesions that heal and slough off in a few weeks, so the condition resolves itself. But in more severe cases, like the bird in this image, the lesions become large and cover much of the head, often interfering with vision and the bird’s ability to feed, and sometimes contributing to mortality. Avian pox is spread by mosquitoes and outbreaks are more common during hot months when mosquitoes are abundant. The virus is also highly transmissible, so when one bird becomes infected it’s likely other birds will as well – this is one reason why concentrating birds around feeders can be problematic, as the virus can be easily spread. The impact that avian pox has on wild turkeys at a population level is unclear and is difficult to determine precisely, although ongoing work shows that many dead birds who test positive for avian pox also test positive for other diseases. The take home is avian pox is a common disease affecting wild turkeys, but the severity of the infection varies considerably across individuals.
Pic by Gregory Cowles.
