Scientists Discover New Virus That Cause Beak Deformities in Birds

Scientists have discovered a new virus responsible for causing mysterious deformities in birds.

Researchers from the California Academy of Sciences, University of California San Francisco (UCSF) and the U.S. Geological Survey (USGS) have found the new virus that has been linked to Avian Keratin Disorder (AKD), a disease that causes debilitating beak overgrowth.

The disease has affected populations of wild birds around the world, and the cause has remained elusive despite decades of research.

"Take one look at a bird suffering from Avian Keratin Disorder, and you'll understand the importance of stopping its spread," Jack Dumbacher, Academy curator of ornithology and mammalogy and co-author of the study, said in a press release.

"Birds must be able to feed themselves and preen their plumage by carefully spreading waterproofing oils on their feathers. When deformed beaks restrict them from these life-giving activities, birds become cold, hungry, and often die. We're trying to understand the causes, origins, and distribution of this disorder."

Avian Keratin Disorder is characterized by severe beak deformities such as elongation, crossing or curvature. The deformities affect birds' basic behaviors such as feeding and preening, which are crucial to their survival.

The mysterious condition was first documented among a population of black-capped chickadees in south-central Alaska in the 90s and spread into Canada and the Pacific Northwest.

Previous AKD studies point to possible causes including bacterial or fungal infection, avian diseases, human food sources, environmental contaminants, behavioral changes or trauma.

But after genetic testing of pathogens in samples taken from Alaska, the research teams were able to track down a cryptic virus hiding in the birds' DNA.

In the study, which was published in mBio, the researchers took tissue samples from both sick and healthy birds, and through advanced sequencing technology, they were able to pull out genetic information from microbes inside the birds.

From the fragments of potential viruses, the research team found the culprit, which belongs to the picornavirus family - a large and diverse group that includes polio, hepatitis A and the common cold. The virus, which was named Poecivirus, remains the strongest lead to AKD, researchers said.

The research team also generated a detailed map of Poecivirus' genetic material, which will help scientists all over the world track bird species affected by AKD.

"We detected Poecivirus in red-breasted nuthatches and northwestern crows with beak deformities, as well as in every chickadee with AKD that we have tested," Maxine Zylberberg, UCSF researcher and lead author of the study, said in the same statement.

"More work is needed to determine if Poecivirus is causing AKD, but the evidence suggests that it is a strong candidate."

For the next step in the research, the scientists will investigate how AKD is transmitted and understand how the virus stimulates abnormal beak growth.