USDA Wildlife Services Aids in Discovery of Mysterious Eider Virus

Wildlife Services employs a diverse team of wildlife experts who help resolve a wide array of human-wildlife conflicts. Wildlife disease management is one area where our expertise in capturing and handling wildlife is frequently called upon by our conservation partners. I am pleased to present the following story how a Wildlife Services disease biologist in Massachusetts made important contributions to the discovery of a new virus impacting a keystone waterfowl species.

APHIS Wildlife Disease Biologist Randy Mickley
Image Credit: Randy Mickley, USDA APHIS Wildlife Services

Since 1998, thousands of North America’s largest sea duck, the Common eider (Somateria mollissima), have been mysteriously dying on Cape Cod’s beaches. Nantucket Sound is the winter home to many thousands of these eiders at the southern edge of their Atlantic coast range. Eiders are an important indicator species of ecosystem health, but since 2006 more than 6,000 common eiders have fallen ill around Cape Cod National Seashore’s Jeremy Point near Wellfleet, Massachusetts where a large mussel bed attracts them.

With concerns about the population-level impact this disease could have, the U. S. Fish and Wildlife Service enlisted the help of USDA APHIS Wildlife Services to determine the underlying cause of these unexplained deaths. With cooperation from over twenty federal, state and university collaborators, APHIS wildlife disease biologist Randy Mickley has provided thousands of biological samples from dead and sickened common eiders to the U. S. Geological Survey’s National Wildlife Health Center in Madison, WI and the Southeastern Cooperative Wildlife Disease Study in Athens, GA for laboratory analyses. Necropsies and tests conducted on these samples indicated that a virus was the cause of illness in the majority of these cases. In 2010, pathologists were finally able to isolate a previously unrecognized orthomyxovirus, tentatively named the Wellfleet Bay virus, after its geographic origin.

Seroprevalence studies from common eider populations across their Atlantic breeding range showed Massachusetts’s common eiders have the highest incidence of exposure to Wellfleet Bay virus. Genomic analysis of the Wellfleet Bay virus has indicated a tick vector may be involved in transmission. GPS telemetry and DNA marker studies are underway to try to identify a source of the virus and mode of transmission. By developing a better understanding of eider movement patterns, scientists hope to better manage the disease and prevent its expansion to other parts of the eider’s Atlantic range.

Wildlife Services is a Strategic Partner of The Wildlife Society.