(e) = estimate; “suspect” = Diagnosis not finalized, but field signs and historic patterns indicate the disease.

Center for Disease Control (CDC), California State University at Stanislaus (CSS), Maryland Diagnostic Laboratory (MD), Michigan Department of Natural Resources (MI), Michigan State University (MSU), Montana Fish, Wildlife and Parks Diagnostic Lab (MT), No diagnostics pursued (NON), Nevada Dept of Agriculture - Animal Disease & Food Safety Lab (NVA), National Veterinary Services Laboratory, Ames IA (NVL), USGS National Wildlife Health Center (NW), Other (OT), Southeastern Cooperative Wildlife Disease Study (SCW), South Dakota University Diagnostic Laboratory (SD), University of California-Davis (UCD), Unknown (UNK), Washington State Disease Laboratory (WA), Wisconsin Veterinary Diagnostic Laboratory (WVL).

Written and compiled by: Anne Ballmann - Eastern US, Krysten Schuler - Western US, and Julia Hoeh – Technician.

To report mortality or receive information about this report, please contact the USGS National Wildlife Health Center, 6006 Schroeder Road, Madison , WI 53711

Quarterly Mortality Reports

Virulent Newcastle Disease responsible for cormorant mortalities in multiple Minnesota counties (MN)
Summer mortality events beginning in July 2008 involving double-crested cormorants were determined to be the result of virulent Newcastle Disease (vND) in 8 MN counties. In addition, individual cases of Newcastle Disease in cormorants were reported to NWHC from WI, MI, CT and MO. Mortality counts ranged from less than 10 birds up to 1200 birds at the various sites and often included other species such as ring-billed gulls and American white pelicans. While the virus was isolated from several pelicans and a common loon in this epizootic, characteristic brain lesions were not observed. At one MN site, infections of West Nile virus, salmonellosis, and intestinal parasitism contributed to the large number of pelican mortalities (1900 estimated) where the overall avian mortality was estimated to be 2500 birds. This was the second consecutive year that vND occurred at two of the MN sites. On-site incineration of carcasses and restricted access to affected areas were instituted to reduce spread of the virus. Canada also experienced increased cormorant mortality associated with avian paramyxovirus-1, the agent of Newcastle Disease, this summer around Lakes Ontario, Erie and Huron. Virulent Newcastle Disease outbreaks in cormorants have occurred intermittently throughout the United States since 1992. No known domestic poultry was involved with this summer’s outbreak.

Botulism type C outbreaks at the Capital Reflecting Pool (Washington, DC)
On July 11, 2008, Capital Police observed multiple mallard ducks displaying neurologic signs and dying upon entering the Capital Reflecting Pool. Earlier reports in the vicinity that day indicated possible human illnesses which were later found to be unrelated. Onsite testing conducted by the FBI was negative for particular agents of concern and the US National Park Service Crew Supervisor confirmed no pesticide application had occurred recently in the immediate area. A total of 17 mallards were collected from the pool and necropsied at the MD Veterinary Diagnostic Lab. Tissues from those necropsied and an additional dead mallard collected from a nearby park were flown to NWHC for further evaluation. Botulism type C toxin was detected in samples from both locations. A second mortality event at the Reflecting Pool, involving 26 mallards, occurred on July 26-27. Samples submitted to NWHC were again confirmed to be botulism type C. Since draining and cleaning of the Pool as the potential source of the toxin, no additional mortalities have been reported.

Botulism type E mortalities recurring in the Great Lakes region (Lakes Michigan, Erie and Ontario)
Beach monitoring along the shores of the Great Lakes this summer has again detected a variety of birds dying from botulism type E intoxication. The first mortality reports attributed to the toxin began in late June from the western shores of Lake Michigan (Mason Co., MI) and northern shores of Lake Ontario (Canadian Cooperative Wildlife Health Centre reporting). Species affected have been mostly common loons, double-crested cormorants, several gull species, and various shorebirds, including Caspian terns and sandpipers. Botulism Type E was also suspected in the death of an endangered piping plover juvenile at Sleeping Bear Dunes National Lakeshore. Four affected Michigan counties (Oceana, Mason, Benzie, and Emmet) represent the furthest southern extent reported along the western Lake Michigan shoreline. Along the eastern shore, September mortalities were detected in Door (bayside) and Milwaukee counties in Wisconsin. Total numbers of birds affected thus far are estimated at 200 for Lake Michigan, 113 for Lake Erie, and 12 for Lake Ontario. Last year, the total mortality from the four lakes was estimated at 17,125 with the majority of the mortalities detected between Oct-Nov. Botulism type C toxin has been detected at some locations including the Kingston, Ontario area and Presque Isle State Park (Erie, PA).

Seasonal summer avian botulism outbreaks across the states (HI, CA, NV, UT, MT, ND, SD, WI, FL, OH, PA, MA)
Botulism type C mortality events were observed in waterfowl across several states during the summer months. Botulism mortality occurs when birds ingest toxins produced by Clostridium botulinum bacteria. The Midway Atoll experienced a significant die-off of endangered Laysan ducks. An estimated 140 ducks died in a population of approximately 200-400 individuals. US Fish and Wildlife Service management actions were to drain and remove sediments from a catchment pond that was the primary site of the event. The largest avian botulism event was at Lake Bowdoin, Montana, where 2000 ducks and coots died in two locations on the lake. Turtle Lake Wildlife Development Area, North Dakota, experienced a month-long botulism event that killed more than 700 ducks and coots. Another large event occurred at Horicon National Wildlife Refuge, Wisconsin, where approximately 1000 birds, primarily mallards and green-winged teal, died over a 6 week period. The Salton Sea National Wildlife Refuge, California, lost 200 birds, mostly American white pelicans and some endangered brown pelicans, black-legged stilts, and gulls. Many affected areas experience annual mortality from botulism. Dry conditions, hot temperatures, and low oxygen levels in wetlands during late summer contribute to botulism outbreaks. Prompt carcass removal of impacted areas can reduce additional mortality from birds eating toxin-contaminated maggots on decomposing carcasses.

Expansion of plague-affected area into black-footed ferret area in Conata Basin (SD)
Sylvatic plague reached the Conata Basin area of South Dakota earlier this July. The Conata Basin is a portion of the Buffalo Gap National Grasslands, south of Badlands National Park, where the last remaining plague-free area existed for black-footed ferret reintroduction. Prior estimates indicated the plague had spread to about 10,000 of the 25,000 acres of black-tailed prairie dog habitat. Prairie dogs carry fleas infected with Yersinia pestis, the bacteria that causes plague. Black-footed ferrets primarily feed on prairie dogs. Ferret populations in Conata Basin were estimated around 300 animals (roughly half of the free-ranging black-footed ferret population), but the plague outbreak may have killed as many as 100. Fall spotlight surveys are underway to obtain more accurate estimates. US Fish and Wildlife Service and partners plan to dust 11,000 acres with insecticide and continue to vaccinate ferrets against plague. As a new management option, USGS – National Wildlife Health Center and other partners are working to develop a plague vaccine that can be delivered via oral bait for prairie dogs and ferrets to protect against plague-associated mortalities.

Documented anthrax mortality in wildlife (MT)
Two deer, 14 elk, and a black bear are suspected to have died from naturally occurring anthrax in several creek drainages near a ranch that was experiencing anthrax mortality in bison. An estimated 250 bison died. Wildlife mortalities were spotted during aerial surveys around the ranch by Montana Fish, Wildlife and Parks. Anthrax is a bacterial disease caused by Bacillus anthracis. Bacterial spores can remain dormant in soil for long periods of time and mortalities tend to recur at contaminated sites although this was the first documentation of anthrax in Gallatin County, Montana. Appropriate weather conditions during summer promote germination of the spores that animals then ingest during feeding. Since anthrax is a zoonotic disease Montana Fish, Wildlife and Parks provided information on proper field dressing of harvested animals to hunters.

Epizootic hemorrhagic disease detected in northern US (WA, SD, MI)
Reports of epizootic hemorrhagic disease (EHD) in white-tailed deer occurred in 3 new northern states during August and September 2008. Die-offs involving 20-500 animals were detected in the Snake River Drainage area (Walla Walla, WA), Butte and Lawrence counties (SD) and Oakland County, MI. EHD is cause by a virus, closely related to bluetongue viruses, and is transmitted by the Culicoides sp. midge. Because of the insect vector, mortalities are more commonly detected in the southeastern US, although it has occurred previously in CO, AZ, and NE. A northward range expansion in the eastern US was noted in 2007 (2007-4 Quarterly Mortality Report).