(CN) – Bald eagles are dying from a new disease that mimics the symptoms of hepatitis C in humans and has been found in birds across the country, according to research released Friday.
Infected eagles were discovered while researchers were studying a deadly syndrome native to the Lower Wisconsin River that causes eagles to stumble, vomit and have seizures.
Of 47 eagles tested across 19 states, researchers found 32% were infected with bald eagle hepacivirus, or BeHV, according to the study published in the journal Scientific Reports.
Researchers from the University of Wisconsin-Madison, the U.S. Geological Survey National Wildlife Health Center and the Wisconsin Department of Natural Resources thought BeHV was exclusively linked to Wisconsin River Eagle Syndrome (WRES), but that wasn’t the whole story.
The team found the virus in seven states in the Midwest, but also in birds of prey in Washington state and Florida. Eagles in Wisconsin were more likely to carry the new virus, and it was 14 times more common in counties that surround the Lower Wisconsin River, according to the study results.
The fact that eagles collected outside Wisconsin were infected with the new virus suggests it may not be exclusively linked to the syndrome.
Tony Goldberg, a UW-Madison professor, led the study and questioned if the virus is the cause of the syndrome or if the topic is more complicated.
Goldberg’s lab is custom fit to discover new viruses and his team analyzed the genetic material of BeHV infected tissue, finding liver damage similar to symptoms humans experience from Hepatitis C infections.
Some explanations offered by the study say infected birds may be more likely to die of starvation or other illnesses before they show symptoms of the syndrome. There’s also the possibility the Wisconsin River provides a suitable habitat for the raptors to survive long enough for the disease to progress to the end stage, according to the study authors.
LeAnn White with the USGS National Wildlife Health Center said lesions found in the livers of dead eagles are nonspecific and there’s still more work needed to understand the virus and the syndrome.
Sean Strom with the Wisconsin Department of Natural Resources said, “We don’t think this virus is having a serious impact on the bald eagle population, but the fact that WRES is an unknown condition keeps our interest.”
In 2007, the bald eagle was endangered with just 412 nesting pairs across the United States, but more recent estimates show 1,700 nesting pairs in the state of Wisconsin alone.