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Avian cholera suspected in snow geese deaths
Friday, Jan 13, 2006
By Joe Mosby
Arkansas News Correspondent
A suspected outbreak of avian cholera has killed 1,300 to 1,500 snow geese at Bald Knob National Wildlife Refuge in north-central Arkansas, according to U.S. Fish and Wildlife Service officials.
The dead include some Ross' geese, a smaller cousin of snow geese.
Wildlife officials say humans are not at a high risk for infection with the bacterial strain causing avian cholera.
Refuge workers found the dead and dying geese Monday, according to Dennis Widner, head of the agency's East Arkansas refuges that also include Cache River, Wapanocca and Big Lake.
The refuge is two miles south of Bald Knob in White County and is on the White River. It covers 14,800 acres and is the newest of the Arkansas national wildlife refuges, created in 1993.
Widner said when the dead snow geese were found, he contacted the U.S. Geological Survey Wildlife Health Center in Madison, Wis., and the Southeastern Cooperative Wildlife Disease Study at the University of Georgia College of Veterinary Medicine, both leaders in the field of wildlife diseases.
Based on the description of symptoms provided by the refuge biologists, experts from both locations suspected avian cholera.
The outbreak is confined at present to snow geese and Ross' geese with no other species of waterfowl affected, Widner said. The birds are contained in a part of the refuge that is designated as a sanctuary and not accessible to the public.
"We are doing everything possible to contain the disease outbreak here at the refuge by not disturbing the rest of the flock of geese here now," Widner said. "While we can't capture the thousands of geese here, our recovery operations are designed to not chase them away from this site. This should help reduce the chance of spreading the disease."
Dr. Lou Sileo, a wildlife pathologist from the National Wildlife Health Center, made a field diagnosis at the refuge this week and said the snow geese found dead on the Bald Knob refuge most likely died from avian cholera, a bacterial infection which is one of the most prevalent diseases in waterfowl populations nationally.
Specimens have also been collected and shipped to the NWHC for complete necropsies, which is standard procedure to confirm the field diagnosis, he said.
"We have done field necropsies that have all indicated avian cholera as the cause of death," said Sileo. "We will need laboratory confirmation to be 100 percent certain."
Outbreaks of avian cholera are fairly common, especially in California, Texas and Oklahoma, and occur among many waterfowl species, according to the Fish and Wildlife Service.
In the past six years, there have been 41 outbreaks of avian cholera across the United States that killed nearly 70,000 geese, ducks, grebes and other species.
Snow geese populations have greatly expanded in the past two decades. Waterfowl biologists are concerned that the large numbers of snow geese are destroying the prime nesting habitat for all bird species and other wildlife in the Hudson Bay area of Canada.
Concentrations of wintering snow geese continue to grow each year in Arkansas and surrounding states. Fish and Wildlife officials said the growth could be a contributing factor to infection outbreaks. Another factor may be reduced habitat from lack of rain that concentrates flocks onto smaller wetlands - increasing the transmission of disease.
The Fish and Wildlife Service has liberalized snow geese hunting regulations to reduce the size of their populations and thin out the number of birds on the breeding grounds in Canada and the affects on other species.
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