^A **** = cessation date not available.

^B (e) = estimate, *** = mortality estimate not available.

^C Suspect diagnosis = diagnosis is not finalized or completed tests were unable to confirm the diagnosis, but field signs and historic patterns indicate the disease.

^D Alaska Department of Fish and Game (AKF), Cornell University (COR), Canadian Cooperative Wildlife Health Centre (CCW), USDA Foreign Animal Disease Laboratory (FAD), Florida Fish and Wildlife Conservation Commission (FL), Idaho Wildlife Health Laboratory (ID), Michigan Department of Natural Resources (MI), National Oceanic & Atmospheric Administration (NOA), No diagnostics pursued (NON), USGS National Wildlife Health Center (NW), Other (OT), Sea World (SW), University of Connecticut Wildlife Laboratory (UCT), University of Florida (UFL), University of Georgia Veterinary Diagnostic Laboratory (UGA), Unknown (UNK), Utah Division of Wildlife Resources (UT), Washington State Disease Laboratory (WA), Wisconsin Department of Natural Resources (WI).

Written and compiled by the U.S. Geological Survey National Wildlife Health Center Field Investigations Team members: Anne Ballmann, LeAnn White, Barb Bodenstein, Jenny Chipault and Jennifer Buckner.

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

For single animal mortality, nationwide, please contact: Jennifer Buckner, USGS National Wildlife Health Center Biologist by phone: (608) 270-2443, fax: (608)-270-2415, or email: jBuckner@usgs.gov

Quarterly Mortality Reports

Avian Botulism Type C throughout the U.S.
Late summer and early fall represents the peak period for avian botulism events and in 2011 botulism type C events were confirmed or suspected in all four migratory bird flyways.

In the Atlantic Flyway, botulism type C was the suspect cause of death for a mortality event in Orange County, Florida involving approximately 50 resident Muscovy Ducks (Cairina moschata).

In the Mississippi Flyway, mortality associated with botulism type C affected around 400 birds, with most of the events occurring in community ponds and retention areas and affecting primarily Mallards (Anas platyrhynchos) and Canada Geese (Branta canadensis).

The deaths associated with type C botulism were much higher in the Central Flyway which had almost 3,000 bird deaths, primarily in waterfowl species. The largest event in this flyway occurred at Blue Blanket Lake, Walworth County, South Dakota where over 1,000 Redheads (Aythya americana), Gadwalls (Anas strepera), Blue-wing Teal (Anas discors), Mallards and American Coots (Fulica americana) were affected.

In the Pacific Flyway, ten confirmed avian botulism events were investigated by the USGS National Wildlife Health Center (NWHC) and partnering agencies in Arizona, California, Nevada and Oregon. In addition, several mortality events in Utah and California were suspected to be avian botulism type C. Mortalities involved less than 200 birds per event with the exception of an event that occurred in Nevada on private land near Carson Lake State Wetland Complex and Fallon and Stillwater National Wildlife Refuges. Due to the flooding of vegetated fields during hot weather, conditions at this location were favorable for botulism. This was the largest reported botulism event in the country this year and involved an estimated 3,000 waterfowl and shorebirds of various species. In consultation with NWHC, Nevada Division of Wildlife and U.S. Fish and Wildlife Service biologists were able to respond and provide daily carcass pick up and disease management activities to mitigate the extent of this die-off. Disease management activities were essential since the location of the mortality was within two miles of a migratory staging area for over 80,000 additional waterfowl and shorebirds. One of the species most affected early in the mortality event were White-faced Ibis (Plegadis chihi).

Avian botulism Type E in the Great Lakes Region
Avian botulism type E mortality events, which are typically confined to the Great Lakes in the United States, were confirmed on Lake Ontario (Monroe and Wayne Counties, New York), northern Lake Erie, southeastern Georgian Bay on Lake Huron, and on Lake Michigan (Door County, Wisconsin and Leelanau County, Michigan). The botulism-confirmed mortality events on Lake Michigan were much larger than those reported on Lake Ontario; however, active surveillance for bird mortalities is conducted on Lake Michigan by Sleeping Bear Dunes National Lakeshore volunteers and USGS Avian Monitoring for Botulism Lakeshore Events Program (AMBLE) volunteers. The largest mortality event occurred at Lake Huron beginning in August, and affected fish (mostly sturgeon) and later birds. Avian mortalities occurred between September and October with an estimated total mortality of 3,000-8,000 birds: affected species included Ring-billed Gulls (Larus delawarensis), Herring Gulls (Larus argentatus), Common Loons (Gavia immer), Red-necked Grebes (Podiceps grisegena), Long-tailed Ducks (Clangula hyemalis), and White-winged Scoters (Melanitta fusca). Reporting agencies include National Wildlife Health Center, Cornell University, and Canadian Cooperative Wildlife Health Center.

Mortality in captive Mississippi Gopher Frog larvae (Harrison County, Mississippi)
In September, the USGS National Wildlife Health Center (NWHC) was contacted for assistance with an overnight mortality event involving approximately 2,400 newly hatched endangered larval Mississippi Gopher Frogs (Rana sevosa). The tadpoles originated from portions of several egg masses that had been collected one week earlier from a single natural pond for captive propagation. No natural mortality among adults or egg masses was observed at the pond at the time of collection. NWHC received representative specimens from each egg mass for diagnostic evaluation. Notable abnormalities in the 1-2 mm sized hatchlings from two egg masses included the presence of blisters and fluid accumulation in the skin and tails. Many of the tadpoles also had oddly curled tail tips. It could not be determined if these lesions occurred before death or represent post-mortem artifact. In addition, some of the tadpoles appeared too underdeveloped to have hatched under normal conditions, suggesting that some of the eggs might have prematurely burst open releasing the tadpoles. The cause of mortality is still under investigation although adverse husbandry conditions, such as exposure to acidified water, are one possible explanation for these findings. No fungi were observed and no viruses were isolated from pooled samples. Mississippi Gopher Frogs, a federally-listed species since 2004, currently number less than 100 adults in two isolated populations in southern Mississippi. An undescribed systemic Perkinsus-like protozoan infection and chytridiomycosis are known disease threats to the remaining population, as is predation of egg masses by Caddisfly larvae and snakes.