(e) = estimate; * = morbidity, not mortality

California Animal Health FS Laboratory Network (CAF), Florida Fish and Wildlife Commission (FL), Florida Fish and Wildlife Research Institute, St. Petersburg, FL (FMR), Idaho Wildlife Health Laboratory, Boise, Idaho (ID), Maryland Diagnostic Laboratory (MD), Michigan State University (MSU), Minnesota Department of Natural Resources (MNS), Nevada Veterinary Diagnostic Laboratory (NV), National Veterinary Services Laboratory, Ames, IA (NVL), National Marine Fisheries Service (NMF), Purdue University Animal Disease Diagnostic Laboratory (PUL), Southeastern Cooperative Wildlife Disease Study, Athens, GA (SCW), Tufts, Cummings School of Veterinary Medicine (TU), USGS National Wildlife Health Center (NW), University of Florida (UFL), Virginia Game and Fish (VA), Wisconsin Veterinary Diagnostic Laboratory (WVL), Wisconsin Dept. of Natural Resources (WI), Washing Department of Fish and Wildlife (WAS), and Washington Animal Disease Diagnostic Laboratory (WA)

Written and compiled by Rex Sohn -Western US, Kathryn Converse- Central US, Grace McLaughlin - Eastern US, NWHC. The Quarterly Wildlife Mortality Report is available at http://www.nwhc.usgs.gov. To report mortality or receive information about this report, contact the above NWHC staff, or for Hawaiian Islands contact Thierry Work. Phone: (608) 270-2400, FAX: (608) 270-2415 or e-mail: kathy_converse@usgs.gov. USGS National Wildlife Health Center, 6006 Schroeder Road, Madison, WI 53711.

Quarterly Mortality Reports

White Pelican Mortality due to West Nile Virus
In late July 2005 wildlife biologists from the Nevada Department of Wildlife and the U.S. Fish and Wildlife Service began observing sick and dead American white pelicans at saline wetlands in western Nevada. Over 90% of the pelicans observed were adults and 45 affected pelicans were picked up at the wetlands through early September. Sick birds were lethargic and lacked muscle coordination. Oral swabs from seven birds were confirmed positive for West Nile virus (WNV) by the State of Nevada WNV surveillance system. Subsequently, two of three adult pelicans submitted to the NWHC for diagnostic evaluation were positive for WNV by virus isolation. Significant mortality of juvenile American white pelicans also continued for the fourth consecutive year in Montana, North Dakota, South Dakota and Minnesota colonies. Similarly, mortality first noted in late June and July, continued until the birds fledged in August. Banding and surveillance data are being analyzed to determine the overall losses and fledging success in these colonies. There is concern that continued annual WNV mortality will have a negative impact on this species. If histopathology links the pelican mortality in Nevada to WNV, it will be the first reported mortality event involving primarily adult white pelicans.

Newcastle Disease in Nevada Double-crested Cormorants
During routine colonial nesting bird surveys at Anaho Island NWR on 8/16/06, U.S. Fish and Wildlife Service biologists discovered 10 dead and 3 sick double-crested cormorant fledglings at a nesting colony with an estimated population of 2,000 cormorants. The sick fledglings, which showed some degree of flaccid paralysis and hemorrhage from the mouth, were euthanized and submitted to the NWHC. Hemagglutination inhibition tests identified virus isolates as NDV. Samples of the viruses were sent to the USDA National Veterinary Services Lab, which confirmed the identification as NDV and determined that the isolates were highly pathogenic for chickens. NVSL conducted genetic analysis of the virus isolates and reported that they were different from the NDV strain that affected domestic poultry in southern California, Nevada and Texas in 2002 and 2003. However, the viruses were determined to have a high genetic homology with strains isolated from double-crested cormorants in the United States since 1992.

Botulism type C at Bear River MBR
From late July to mid-September U.S. Fish and Wildlife Service personnel picked up the carcasses of approximately 6,000 waterbirds from a 1,800 acre wetland management unit at Bear River Migratory Bird Refuge at the Northeast edge of the Great Salt Lake. The primary species involved were dabbling ducks and small wading birds. Ducks that were submitted to the NWHC in early August were positive for botulism type C toxin. The birds were negative for West Nile virus by virus isolation. Bear River MBR has a history of major botulism die-offs tracing back to the early part of the twentieth century. No significant mortality due to botulism type C has been documented since 1997 and 1998; More than 500,000 birds were estimated dead in 1997 and 10,627 birds were picked up in 1998.

Trematodiasis at Upper Mississippi National Wildlife Refuge, Wisconsin (UMNWR).
Blue wing teal began succumbing to trematodiasis in late August, the first time the small puddle ducks have been involved in the seven recurring outbreaks at the UMNWR since Fall 2002. Mortality attributed to infection by two tiny flukes, Sphaeridiotrema globulus and Cyathocotyle bushiensis, had its earliest start yet for waterfowl in their fall migration period. By the end of August, nearly 200 teal and about two dozen other dabbling ducks, including mallards, shovelers, pintail and black ducks, had been found dead. The birds were feeding in wild rice beds in an area of UMNWR where mortality from the trematodes had not previously been recorded. Carcasses of each species found were submitted to the NWHC for necropsies. Ongoing research on the distribution of invertebrates on the UMRNWR and in nearby waterways will help to determine if the non-native faucet snail, Bithynia tentaculata, which can act as both primary and secondary host to the flukes, is increasing its range in the Mississippi River. Monitoring of later-arriving coots and diving ducks will provide data for comparison to die-offs in previous years.

For additional information please contact Dr. Scott Wright, USGS National Wildlife Health Center - Disease Investigations Branch Chief, at 608-270-2460 or Paul Slota, USGS National Wildlife Health Center - Support Services Branch Chief at 608-270-2420.