(e) = estimate, *** Mortality estimate not available at this time, "suspect" = Diagnosis is not finalized, but field signs and historic patterns indicate the disease.

California Animal Health Food Safety Lab Network (CAF), Canadian Cooperative Wildlife Health Center (CCW), Cornell University (COR), Florida Fish and Wildlife Conservation Commission (FL), Idaho Wildlife Health Laboratory in Boise (ID), No diagnostics pursued (NON), USGS National Wildlife Health Center (NW), NY State Department, DEC, Division of Fish, Wildlife & Marine Resources (NY), Oregon State Diagnostic Laboratory (OR), Other (OT), Southeastern Cooperative Wildlife Disease Study (SCW), UC Davis (UCD), University of Connecticut Wildlife Laboratory (UCT), Unknown (UNK), Wisconsin Department of Natural Resources Wildlife Health Lab (WI), 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

Leucistic Tiger salamanders in Yellowstone National Park (WY)
Tiger salamanders (Ambystoma tigrinum melanostictum) were monitored and collected from Slough Creek area of Yellowstone National Park as part of a summer survey. Large numbers of apparently healthy tiger salamanders were found in pools, some of which had severely reduced amounts of black pigment (melanin) in the skin of their heads, bodies and limbs. This condition is known as leucism or leucistic variation, where melanin in skin cells is severely reduced. Leucism is different than albinism where the skin pigment, melanin, is completely absent. Leucism occurs in a variety of different species. Partial leucism is seen occasionally in other species of wildlife and is referred to as “piebald.” During the monitoring of this population of tiger salamanders, a die-off of the aquatic larvae occurred. Healthy animals collected prior to the die-off, sick, and dead salamanders were submitted to NWHC for diagnostic examinations. A ranavirus was isolated from one of the sick salamanders and is the presumptive cause of the die-off. Additional diagnostic tests are in progress. Ranaviral infections are a well-recognized cause of mortality in free-living larval tiger salamanders in Western States and Canada (from Arizona to Saskatchewan). This tiger salamander population in Yellowstone National Park appears to have a unique genetic composition, and this mortality event may be the first occurrence of ranavirus-associated deaths in salamanders within the Park.

Multiple Sandhill crane mortality events in north central Oklahoma (OK)
Lesser sandhill cranes in north central Oklahoma were plagued by a variety of mortality events this winter. Biologists from Salt Plains National Wildlife Refuge responded to a die-off of over 100 cranes in early November. Carcasses examined at NWHC were found to have experienced extreme trauma and had multiple fractures and lacerations without any external evidence of injury. Severe winds during a storm event were the likely cause of death. In late December and mid-January, two separate events occurred with cranes being found dead in peanut fields. The first event involved about 24 birds and the second was 160 birds. The cranes were consuming the peanuts and are suspected to have died from mycotoxin poisoning. Mycotoxins are produced from fungus that grows on the peanuts in appropriate conditions. These fields normally have waste peanuts plowed under the soil, but wet conditions prevented farmers from tilling the fields.

Unusual mortality event in California brown pelicans (CA)
In mid-December, a higher than normal number of California brown pelicans were being submitted to rehabilitation facilities. Sick and disorientated pelicans were being found along the coast from San Francisco down to Los Angeles. The International Bird Rescue and Rehabilitation Center estimated that 300-400 pelicans, both adults and juveniles, were affected. Carcass testing by multiple state and federal labs revealed a variety of findings, including infarcts on the feet (suggestive of frostbite), anemia, and emaciation. Many sick pelicans responded to supportive care in rehabilitation. Field information from Oregon indicated that substantial numbers (~5,000) of brown pelicans were present on East Sand Island at the Columbia River in Oregon in December when typical migration is mid-November. Extremely cold weather during the week of December 10 occurred around the same time that the pelicans started to move south. Corroborating pathology findings and field data indicate that severe winter weather and subsequent forced migration were responsible for some of the observed morbidity and mortality. California brown pelicans have recently been proposed for delisting so understanding impacts of mortality events is critical for continued overall population health.

Soybean impaction in North Dakota waterfowl (ND)
A concerned citizen found nearly two dozen mallards and Canada geese sick and dead in Wells County, North Dakota at the end of October and reported them to North Dakota Game and Fish. The birds appeared to be engorged with soybeans and were emaciated. Sick birds had limp necks, but some were still capable of flying. Examination of carcasses at NWHC found that each bird had a severely distended esophagus with moist soybeans causing pressure necrosis. Blood vessels in the neck above the blockage were swollen with blood suggesting that the obstruction was preventing venous return. Soybean impaction has been previously described in waterfowl when soybeans dry in the field and swell with water after ingestion. This area of North Dakota had weather conditions reported as a wet summer with a dry fall.

Bat White-nose syndrome expands range in Mid-Atlantic states (NJ, PA, WV)
Bat white-nose syndrome(WNS), which was first recognized near Albany, NY in 2006, has been confirmed at hibernacula in 3 new states (NJ, PA, WV) so far this winter. Suspect cases from VA and NH are also currently under investigation (See Weekly Mortality Report Update). Previously, the condition appeared only in hibernacula in CT, MA, NY, and VT. Mortality has been variable at the new sites, but is expected to increase as the season progresses. NWHC has confirmed WNS in little brown bats, northern myotis, eastern pipistrelles, and endangered Indiana bats. Since its discovery, white-nose syndrome may have resulted in the death or disappearance of hundreds of thousands of insect-eating bats in the northeastern United States. Characteristics of the syndrome include behavioral and physical changes, such as large shifts of the roosting bat population to the front of the hibernaculum; day flying activity in suboptimal temperatures; delayed or absent arousal response; white fungal growth on the muzzle, ears, and/or wing membranes; emaciation; and increased winter mortality rates. Center scientists identified a novel, cold-growing fungus, Geomyces sp., invading the skin of bats examined from affected sites. Pathogencity and transmission studies are currently underway. (Blehert et al. 2009. Bat white-nose syndrome: An emerging fungal pathogen? Science 323:227; http://www.nwhc.usgs.gov/disease_information/white-nose_syndrome/index.jsp)

Infected faucet snails detected at Lake Winnibigoshish (MN)
For the second consecutive year, Lake Winnibigoshish experienced avian mortalities this autumn due to intestinal trematodes infections with Sphaeridiotrema globulus and Cyathocoytle bushinesis. Mortalities also were detected at nearby Bowstring Lake (MN) for the first time. An estimated 857 birds died, primarily lesser scaup and American coots. Snail surveys conducted this summer at Lake Winnibigoshish found the invasive host snail, Bithynia tentaculata. Parasite infection rate for snails was between 0-93% with the highest prevalence occurring near shore. All 3 trematodes, S. globulus, C. bushinesis, and Legyonimus polyoon were detected. In some instances, a single snail was infected by more than 1 species of metacercariae, the intermediate life stage of the parasites. Trematode-related waterfowl mortalities in the Upper Mississippi River NWR (WI) also occurred this spring and fall; mortality estimates were 2500-3500 birds, representing a decrease of 80% from 2007 mortality estimates. One possible reason is that lesser scaup were observed flocking in greater numbers at lower pools of the refuge where Bithynia populations are lower. Trematodiasis events have occurred annually at Upper Mississippi River NWR since 2002 with the death of between 50,000-60,000 individuals since its discovery in 2002.

Botulism E bird mortalities down for the Great Lakes in 2008
Avian mortalities attributed to botulism type E in the Great Lakes between Jun - Dec 2008 were significantly less than last year’s estimated total of 17,125 birds despite similar beach survey efforts. Carcass tallies for Lake Ontario were 162 birds and estimate 1628 dead. Lake Erie reported 458 carcasses with estimates of mortality as high as 2005 birds. Lake Michigan reported 234 carcasses. Although total mortalities were low in 2008, the distribution of affected birds expanded further south (Emmet County, MI) along the western shore of Lake Michigan than previously recorded. Lakes Huron and Superior reported no bird mortalities attributed to botulism E. Common loons and various gull species remain the primary birds affected. Type E avian botulism has caused the deaths of thousands of fish-eating birds per year since 2000. Carcasses were received by NWHC for confirmation of botulism type E in 2008 from Lakes Michigan (MI, WI) and Erie (PA), including Sleeping Bear Dunes National Lakeshore in Michigan. Botulinum type C toxin also was identified as the cause of death at some locations including the Kingston, ON (CAN) area and Presque Isle State Park (Erie, PA), earlier in the summer before Type E intoxication was detected.

Avian cholera die-offs in AR waterfowl and Arctic sea ducks (Nanavut)
A die-off event of over 1000 waterfowl, including primarily lesser snow geese, greater white-fronted geese, mallards, and northern pintails, occurred in 3 northeastern Arkansas counties beginning in late November and lasted several weeks. Carcasses were found at a water impoundment area at Bald Knob NWR as well as harvested rice fields in Poinsett and Lawrence counties. Avian cholera was determined to be the cause of death. This is only the second avian cholera die-off recorded from AR. The last event in 2001 involved 206 birds at a private duck club. Another large avian cholera outbreak occurred in Hudson Strait and East Bay Migratory Bird Sanctuary on Southampton Island in the northern Hudson Bay (Nanavut, CAN) colonies this winter. An estimated 1500 common eiders died. According to the National Wildlife Research Centre (Ottawa), East Bay accounts for 1/3 of all breeding female eiders and there is potential for population impacts.