ATHENS, Ga. -- Scientists are no closer to finding the cause of a mysterious malady that is killing bald eagles and waterfowl in several Southern states, despite a recent conference to discuss the problem.
As the conference in Athens drew to a close this week, scientists were worried there could be new outbreaks this winter of avian brain lesion syndrome.
The disease first surfaced at DeGray Lake, Ark., in 1994, where 58 bald eagles have since died. Researchers at first thought the malady was confined to Arkansas.
But last December, a 5-year-old female bald eagle was found dead at Savannah River Site in Aiken County. Just a few days earlier, another bald eagle was found dead at Thurmond Lake in Lincoln County.
Since the first outbreak five years ago, a growing number of scientists and research organizations have joined the effort to solve the mystery, deciding this week to organize a regional task force to study the problem.
The eagles at SRS and Thurmond Lake were the first eagle deaths outside Arkansas, but others have since been reported at Lake Juliette and at Wood Lake, N.C.
This year, it killed eagles and coots in South Carolina, and the discovery of the disease January in North Carolina ducks increased the concern.
Hunters shoot and eat ducks, raising the possibility of a threat to human health, said Vic Nettles, director of the University of Georgia-based Southeastern Cooperative Wildlife Disease Study.
No human cases have been reported, however, and there have been no cases so far outside the four states.
Tissues from infected birds have been examined for bacteria, viruses and parasites that might cause the disease, said Chris Brand of Wisconsin's National Wildlife Health Center.
Scientists have even tested infected birds for prions, the proteins that cause mad cow disease and a similar disease in American elk and deer.
Infected birds have also been tested for dozens of potential toxins, including botulism, pesticides, poisonous plants and heavy metals such as mercury and lead.
The disease shows up as microscopic lesions in the animals' brains and spinal cords.
Researchers have largely ruled out bacteria and viruses as a culprit, leading many to consider the syndrome likely to be caused by an unidentified toxin.
As the malady progresses, birds become uncoordinated and disoriented. Eagles fly into rocks, have trouble walking and wobble when they fly. Coots may swim upside down or find themselves unable to lift off from the water.
Mr. Nettles said one of the top items on scientists' agenda is to procure federal research funds to help with the investigation.
Even though federal wildlife officials have formed a national committee on the issue, there is so far very little federal money available, said Allen Robinson, contaminants program manager for the U.S. Fish and Wildlife Service's Southeastern Region.
Locally, scientists at Savannah River Ecology Lab at SRS are studying coots in efforts to learn more about the disease.
Staff Writer Rob Pavey contributed to this article.