National Wildlife Health Center

...advancing wildlife and ecosystem health

USGS National Wildlife Health Center
Quarterly Wildlife Mortality Report
April 2012 to June 2012

Reported
State
Location Dates A Species Mortality B Diagnosis C Laboratory D
AZ Dewey 06/01/12-07/31/12 Desert Cottontail Rabbit 25 (e) Tularemia AZ, CDC, WA
AZ Pinal County 06/15/12-08/10/12 Eurasian Collared Dove 750 (e) Viral Infection: Avian Paramyxovirus 1 NW
AZ Maricopa County 06/18/12-08/10/12 Eurasian Collared Dove 2300 (e) Viral Infection: Avian Paramyxovirus 1 NW
CA Channel Islands NP 06/01/12-06/22/12 Townsend's Big-eared Bat 11 (e) Emaciation: starvation suspect NW
CA City of Marysville 04/23/12-05/06/12 Mallard, Muscovy Duck 30 (e) Botulism type C CAF
CA Gibson Ranch County Park 04/08/12-04/27/12 American Coot, Mallard, Western Canada Goose 25 (e) Avian cholera CAF
CA Lake Perris 05/30/12-06/13/12 Western Grebe 20 Drowning suspect NON
CA Sacramento 06/08/12-06/22/12 Tricolored Blackbird, American Kestrel, Yellow-billed Magpie 30 (e) Undetermined NON
CA Vasona Reservoir 06/20/12-06/24/12 Western Gull, Unidentified Frog, Common Carp 12 (e) Undetermined CAF
DC Washington DC 06/28/12-**** Mallard 13 Botulism type C NW
FL Brevard County 04/01/12-05/12/12 Brown Pelican 15 (e) Emaciation NW
FL Vero Beach to St Augustine 06/18/12-06/23/12 Greater Shearwater 254 (e) Emaciation NW
HI Kaelepulu Pond 04/14/12-**** Great Barracuda 36 (e) Open NW, OT
HI Kanaha Pond 06/13/12-**** Hawaiian Coot, Hawaiian Stilt, Hybrid Mallard x Hawaiian Duck 67 Botulism type C NW
IN Jefferson County 05/20/12-**** Unidentified Bat 30 (e) Autolyzed/Decomposed NW
MI Gulliver, Lake Michigan 06/06/12-ongoing Red-necked Grebe, Horned Grebe 278 Botulism suspect NON
MI Sleeping Bear Dunes National Lakeshore 06/23/12-ongoing Double-crested Cormorant, Ring-billed Gull, Horned Grebe, Common Loon 523 Botulism type E NW
MN Big Cormorant Lake 05/01/12-**** Mudpuppy Salamander 1000 (e) Open NW
MN Farmington 06/30/12-ongoing Mallard 75 (e) Botulism type C NW
MN Glencoe 04/15/12-04/16/12 Northern Leopard Frog 100 (e) Fungal Infection: chytrid suspect NW
MN Lake Winnibigoshish 04/22/12-05/05/12 Lesser Scaup, Greater Scaup 250 (e) Parasitism: Cyathocotyle bushiensis NW
MS Crescent Lake 05/01/12-05/24/12 Hieroglyphic River Cooter 600 (e) Toxicosis: blue-green algae suspect NW
MS Leake County 05/09/12-05/31/12 Blue Jay 24 Trauma NW
NC Moore County 06/03/12-07/03/12 Big Brown Bat 15 Rabies NW
ND Chase Lake NWR 05/14/12-09/13/12 Unidentified Gull, Unidentified Waterfowl, Double-crested Cormorant, American White Pelican, Cattle Egret 142 (e) Botulism type C NW
ND Divide County 06/02/12-06/02/12 American White Pelican 6 (e) Trauma NW
NE Crescent Lake NWR 06/20/12-ongoing Eared Grebe, American White Pelican 46 Botulism suspect NW
NY Great Gull Island 06/06/12-07/05/12 Roseate Tern 75 Emaciation: starvation NW
NY Seneca County 05/10/12-05/11/12 American Goldfinch 7 (e) Trauma NW
OH Erie County 06/21/12-06/23/12 Mallard, Canada Goose 57 Botulism type C NW
OH Lancaster 06/09/12-06/13/12 European Starling 30 (e) Parasitism: coccidiosis NW
PA York County 05/31/12-06/25/12 Spotted Salamander 10 Viral Infection: Ranavirus NW
SD Swan Lake NWR 06/19/12-08/31/12 Western Grebe, Unidentified Duck or Goose, Mallard, Wood Duck, Franklin's Gull 405 (e) Botulism type C NW
SD Zabrashaw WPA 06/18/12-ongoing Double-crested Cormorant, Eared Grebe, Wood Duck, American White Pelican 479 (e) Botulism type C NW
TX Muleshoe NWR 04/23/12-05/15/12 Northern Shoveler, Blue-winged Teal 10 (e) Open: botulism suspect NW
TX Turtle Bay 04/12/12-**** Brown Pelican 300 Emaciation NW
WA King County 05/24/12-05/24/12 Green-winged Teal, Northern Pintail, Mallard, American Crow 18 (e) Trauma suspect NON
WA Skagit County 06/24/12-07/02/12 Yuma Bat 14 Trauma NW
WI Brown County 05/01/12-06/19/12 Tree Swallow 40 (e) Emaciation: starvation suspect NW
WI Lake Michigan and Green Bay beaches 06/05/12-ongoing Ring-billed Gull, Herring Gull, Double-crested Cormorant 69 Botulism type E NW
WY Grand Teton National Park 06/20/12-09/11/12 Boreal Toad, Columbia Spotted Frog 750 (e) Viral Infection: Ranavirus NW

A **** = cessation date not available.

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

C Suspect = diagnosis is not finalized or completed tests were unable to confirm the diagnosis, but field signs and historic patterns indicate the disease; Open = diagnosis is not finalized and tests are on-going; Undetermined = testing is complete or was not pursued and no cause of death was evident; NOS = not otherwise specified.

D California Animal Health and Food Safety Laboratory Network (CAF), Centers for Disease Control and Prevention (CDC), National Wildlife Health Center (NW), No diagnostics pursued (NON), Other (OT), University of Arizona Diagnostic Laboratory (AZ), Washington State Disease Laboratory (WA).

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

Eastern United States


Dr. Anne Ballmann
Wildlife Disease Specialist
Phone: (608) 270-2445
Fax: (608) 270-2415
Email: aballmann@usgs.gov

Central United States


Dr. LeAnn White
Wildlife Disease Specialist
Phone: (608) 270-2491
Fax: (608) 270-2415
Email: clwhite@usgs.gov

Western United States


Barb Bodenstein
Wildlife Disease Specialist
Phone: (608) 270-2447
Fax: (608) 270-2415
Email: bbodenstein@usgs.gov

Hawaiian Islands


Dr. Thierry Work
Wildlife Disease Ecologist
P.O. Box 50167
300 Ala Moana Blvd., Rm 8-132
Honolulu, HI 96850
Phone: (808) 792-9520
FAX: (808) 792-9596
Email: Thierry_work@usgs.gov

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

Mass mortality of Hieroglyphic River Cooters at rural Mississippi lake (Mississippi)
An estimated 600 river cooters (Pseudemys concinna hieroglyphica) were reported dead at a wooded lake in rural Mississippi in early May 2012. Several private residences with lakeshore access described finding dead turtles all around the lake. The total turtle population density for the location is not known and other turtle species were suspected to reside at the lake as well, however, only river cooters (predominantly adults) appeared to be involved in the die-off. Grass carp had recently been added to the lake to help control aquatic vegetation overgrowth. Common findings among the turtles included good nutritional condition and lack of significant gross or microscopic lesions in multiple tissues. No underlying infectious diseases were detected from bacterial and viral cultures. A variety of parasites were identified but none were at loads considered likely to have a significant impact on the animal�s health. Toxicology screens were negative for heavy metals and over 40 common toxic compounds. Free microcystin and cylindrospermopsin were detected in the livers of two turtles; these toxins are produced by various cyanobacteria (blue-green algae) and may have been the source of mortality in this event. The relative sensitivity of river cooters to these toxins compared to other species is unknown; a higher sensitivity could explain why only cooters were affected.

River cooters are omnivorous, freshwater turtles native to the central and eastern US. They are generally found in rivers with a moderate current but can also be found in lakes and tidal marshes.

Increased Roseate Tern chick mortality observed at Great Gull Island (New York)
Greater than usual chick mortality (75 total) was observed in a well-studied Roseate Tern (Sterna dougalli) population this past spring on Great Gull Island (New York). In previous seasons, fluctuations in the prey base and starvation were suspected to be the cause of chick mortality. Fourteen 2 to 3 day- old chicks were submitted to the USGS National Wildlife Health Center for diagnostic evaluation this season; seven chicks were examined. All chicks were emaciated; some had evidence of hemorrhaging into the intestines which can be associated with simple starvation. No underlying bacterial or viral diseases were detected. Roseate Terns of the Northern Atlantic subpopulation are federally-listed as endangered. Threats to population recovery include predation at nesting sites, habitat degradation from erosion and/or invasive plants, human disturbance, and contaminants. Great Gull Island supports the largest nesting colony (1300 pairs) of Roseate Terns in the Northeast US.

Muskrat mortality observed at two northeastern wildlife refuges (Massachusetts)
Approximately 11 adult muskrats (Ondantra zibethicus) were found sick or dead on the Assabet River NWR and Great Meadows NWR sporadically over a two month period beginning in mid-March 2012. These two refuges are separated by approximately 8 miles but share a common watershed. Clinical signs observed in affected muskrats included lethargy and lack of awareness of their surroundings. Animals submitted to NWHC for diagnostic evaluation were consistently found to be emaciated. Although tularemia was a concern, bacterial cultures were negative for all animals tested as were viral cultures. One specimen submitted from each of the two refuges had evidence of renal nephrosis and acute kidney failure. A small number of suspect calcium oxalate crystals were detected in one individual. Common sources of calcium oxalates are antifreeze (ethylene glycol) or various plants such as Philodendrens, Diffenbachia, Jack-in-the-Pulpit, and skunk cabbage. The origin of suspect oxalate exposure could not be identified, and the number of crystals present was not sufficient to diagnose poisoning by antifreeze. Another finding among the muskrats examined was the apicomplexan protozoal parasite Frenkelia sp. encysted in brain tissues. No inflammation or necrosis was associated with the presence of the parasite as can sometimes occur in this species so these infections were not thought to have directly contributed to their death.

Mudpuppy mortality Big Cormorant Lake (Minnesota)
In May 2012 biologists with the Minnesota Department of Natural Resources reported thousands of dead common mudpuppies (Necturus maculosus) at Big Cormorant Lake, Becker County, MN. The carcasses were observed on shore up to 10 feet from the water�s edge. Since mudpuppies are fully-aquatic salamanders that never form air-breathing lungs, but rather rely on external gills behind their heads to breathe, this distance from the water suggested that sick animals crawled out of the water before dying. Seven animals were submitted to the US Geological Survey�s National Wildlife Health Center (NWHC) for examination. The primary finding for the examined animals was emaciation. No pathogenic bacteria or viruses were isolated from the tissues but most of the examined animals had saprolegniasis (watermold skin infections). It could not be determined, however, whether the watermold growth occurred before or after death as only one mudpuppy arrived alive and watermold growth can occur post-mortem on dead chilled animals. NWHC has been involved with investigations of three other mudpuppy mortality events since 2000 in which a definitive cause of death could not be determined. Although botulism was associated with mortality of other animal species at one of the previous mudpuppy mortality events, botulism tests performed on samples from these mudpuppies were inconclusive. Severe autolysis (decomposition) in the other case interfered with histologic interpretation. Chytrid fungus and ranavirus have not yet been documented in this species.

Investigating alopecia in polar bears of South Beaufort Sea (Alaska)
During late March through May of 2012, the USGS Alaska Science Center Polar Bear Project field capture crew observed alopecia on 23 of 82 (28%) bears captured at the boundary of the Southern Beaufort Sea off the North Slope of Alaska. The USGS Polar Bear Project and the USGS NWHC are investigating the occurrence of the alopecia using various samples that were collected from anesthetized bears during the 2012 field season to attempt to determine the cause of these abnormalities and their potential implications for polar bear health. Similar cases of alopecia were previously observed in approximately 19% of the bears captured by the USGS Polar Bear Project in 1999. Histopathologic findings in biopsy samples from 2012 bears were consistent and characterized by epidermal and follicular hyperkeratosis with variable secondary bacterial folliculitis. These findings are most suggestive of hormonal or nutritional abnormalities, such as hypothyroidism or Vitamin A deficiency, as the cause of hair loss in affected bears. Vitamin A deficiency most often results from inadequate dietary intake, while hypothyroidism can occur as a secondary effect of a number of conditions. Documented conditions causing hypothyroidism in bears include exposure to organochlorine (OC) and/or polychlorinated biphenyl (PCB) compounds. Flame retardants (PBDEs) also may suppress thyroid hormone activity due to their chemical similarity to PCBs. Further investigations as to the underlying cause are underway.

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