(e) = estimate * = morbidity and mortality

California Dept. of Fish & Game-Wildlife Invest. Lab (CA); Centers for Disease Control, Ft. Collins, CO (CDC); Colorado Division of Wildlife (CO), Connecticut Ag. Exp. Station & Univ. of Connecticut (CT); Illinois Dept. of Nat. Res. (IL); Live- stock Disease Diagnostic Center (KY); Louisiana Game & Fish (LA); Nat'l Wildlife Health Center (NW); New Jersey Dept. of Fish & Wildlife (NJ); New York State Dept. of Env. Cons. (NY); Purdue Diagnostics Lab (PD); Southeastern Cooperative Wildlife Disease Study (SC); US Geological Survey (GS), Washington Dept. of Fish & Game (WA), and Wisconsin Dept. of Nat. Res. (WI).

Written and compiled by Kathryn Converse, Kimberli Miller, Linda Glaser, and Audra Schrader, National Wildlife Health Center (NWHC). To report mortality or if you would like specific information on these mortalities, contact one of the following NWHC staff: Western US Kathryn Converse; Eastern US--Kimberli Miller; Hawaiian Islands--Thierry Work. Phone (608) 270-2400, FAX (608) 270-2415 or E-mail kathy_converse@usgs.gov. National Wildlife Health Center, 6006 Schroeder Road, Madison, WI 53711.

Quarterly Mortality Reports

There were 4 die-offs this quarter with estimated losses equal to or greater than 4,000 birds. The largest event occurred in mid October, when over 20,000 red-winged blackbirds and nearly 6,000 brown-headed cowbirds were found dead and dying in an Illinois wheat field during an intentional poisoning event involving the carbamate compound carbofuran. US Fish & Wildlife Service Law Enforcement and IL Department of Conservation Officers investigated the incident.

California Dept. of Fish and Game informed the National Wildlife Health Center (NWHC) of a fall avian botulism die-off at Leavitt Lake in California leaving an estimated 8,000 waterfowl dead (primarily shoveler, pintail and coots). The Department launched a major carcass pick up effort. The last known botulism die-off at this site occurred in the late 1980's and involved 300 birds. This year's mortality was considered significant because it was believed the waterfowl losses were at least equal to the total annual waterfowl production of all the Northern California-North Coastal Region Wildlife Areas.

From early November through late January, approximately 5,000 pintails and mallards died due to lead poisoning at Catahoula Lake in Louisiana. This was the worst lead poisoning event there since 1989. Contributing factors included an increase in duck numbers, lower than usual lake levels due to ongoing drought conditions, and birds feeding at the lake instead of nearby agricultural fields and wetlands normally flooded at this time of year.

Over 4,000 birds, primarily coots, were collected during a dieoff at Lake Shawano near Green Bay, Wisconsin. The cause of the mortality was due to the parasite Leyogonimus polyoon. This parasite was first detected during a waterbird dieoff at this site in 1997 when coot losses exceeded 11,000 birds. Retrospective work revealed this parasite was responsible for a 1996 dieoff at the site also. Although this is a common cause of coot and moorhen mortality in Eastern Europe, it had never been reported in North America. Lake Shawano continues to be the only known North American site where this disease has occurred.

Avian Vacuolar Myelinopathy (AVM), the unusual neurologic disease in coots, eagles, and waterfowl that has occurred nearly annually since 1994 was documented again in the fall of 1999 in all the previously known locations. NWHC confirmed the disease in coots on Wood Lake, North Carolina. The Southeastern Cooperative Wildlife Disease Study confirmed the disease in coots on Lakes De Gray and Ouachita in Arkansas, Lake Juliette and Strom Thurmond Lake in Georgia, and Lake Murray and 2 lakes near Aiken, South Carolina. One eagle from Lake Ouachita is confirmed with the disease and another from the same lake is a suspect mild case. Brains from eagles from Arkansas and one collected near Aiken, SC are being examined for the lesion. So far, it appears to be a mild year for AVM with few losses and no new locations or species reported.

An iridovirus infection is suspected as the cause of death in over 500 Northern Leopard frogs in a creek in McLean county, North Dakota. Additional virology and diagnostic samples are in progress. A similar virus was isolated from a North Dakota salamander die-off in 1998.

The West Nile virus (WNV) die-off in crows continued through October and into November in the New York City area. Thousands of crows are estimated to have died and crows were found positive for WNV in 10 counties in New York, 15 counties in New Jersey, and 2 counties in Connecticut. Eighteen native species were found positive for the virus although it is unknown whether all these species died from the infection (see NWHC website information on WNV for list of species at ). One crow from Baltimore, MD was also found positive for the virus. This was the only dead bird found positive for WNV outside of the 3-state area of NY, NJ, and CT. West Nile virus is an arthropod-borne virus, never previously reported in the Western hemisphere, which generally causes a milder disease in humans than St. Louis encephalitis virus; however it can cause human fatalities, especially in the elderly, and seven people died out of 61 clinically ill people during this outbreak in New York City. Crows with WNV infection were used as a sentinel system to detect the presence of the virus in an area and guide decisions on public health response efforts. Bird surveillance to detect WNV activity is planned for the next mosquito season in multiple states along the Atlantic and Gulf coasts. Bird surveillance was listed first in recommendations outlined by CDC for WNV surveillance in the January 21st Morbidity and Mortality Weekly Report.

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.