(e) = estimate; * = morbidity and mortality

National Wildlife Health Center (NW); Southeastern Cooperative Wildlife Disease Study (SC); California Department of Fish and Game - Wildlife Investigations Laboratory (CFG); University of Florida-Gainesville (FL), Rose Lake Wildlife Disease Laboratory-Michigan (MI), Wisconsin Department of Natural Resources (WI).

Written and compiled by Kathryn Converse, Kimberli Miller, Linda Glaser, Terry Creekmore, 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

The following highlights wildlife morbidity and mortality events reported to the National Wildlife Health Center (NWHC) from April through June 1998. There were 26 reports this quarter.

Newcastle Disease along with colony abandonment is suspected to be the cause of mortality again this year in a double-crested cormorant colony in Salton Sea located in southern California. Mortality, estimated at 6000 young of the year cormorants, occurred early this spring on the Mullet Island colony of 2700 nests. Older juveniles exhibited the characteristic neurological signs of ND including spastic paralysis of one wing or leg. Young of the year birds were found sick or dead and ranged in age from nestlings (<3 weeks of age) to immature birds (3-8 weeks of age). Diagnostic evaluation revealed the microscopic lesions in brain and spinal cord associated with ND but a virus has not been isolated from these birds. Virus isolation and identification of the Newcastle Disease Virus (NDV) are required to confirm the diagnosis. Newcastle Disease caused significant mortality last year in this same nesting colony.

A large die-off of tiger salamanders was reported to NWHC by USFWS personnel from a 3-part wetland in south central North Dakota. Mortality was first observed in late May in the smallest section of the wetland and spread throughout the wetland within a month's time. Salamanders in a late stage of larval development appeared to be sick, moving slowly, and staying close to the water's edge. Other species using the wetland including birds, fish, and turtles, appeared to be unaffected. Sick and dead salamanders were submitted to the NWHC for diagnostic evaluation. Evidence of cell death in the liver and spleen was observed microscopically but no cause for these lesions has been found. Diagnostic evaluation continues. Last year, the Canadian Cooperative Wildlife Health Center in Saskatoon, Saskatchewan found that a virus was the cause of mortality in tiger salamanders from several sites in the prairie provinces.

In April 1998, an incident of mortality in American coots in northern Wisconsin was again attributed to infection by the trematode Leygonimus sp. As in the fall of 1997, concurrent mortality in lesser scaup on the same lake was attributed to infection by the trematode Sphaeridiotrema sp. This is the second known record of this trematode infecting coots in North America.

The New York Department of Conservation reported ten cases of individual poisonings in birds that are not listed in the mortality events table but merit comment. Intoxication with Brodifacoum, an anticoagulant rodenticide, was confirmed in a great horned owl collected in Dutchess County in June 1997, a great horned owl collected in Genesee County in April 1997 and in a screech owl collected in Erie County in October 1997. The owls were secondarily poisoned, most likely due to eating animals that had ingested the rodenticide. Chlordane poisoning was confirmed in an American crow and a blue jay collected July 1997 and a red-tailed hawk collected in September 1997 in three towns in Suffolk County, Long Island; in an American crow collected in Stamford, Connecticut in July 1997; and in a blue jay collected July 1997 in Nassau County, Long Island. Chlordane is a persistent toxicant used in the past for termite and turfgrass insect control. A house sparrow collected July 1997 and a white-throated sparrow collected December 1997 were non-target species that were poisoned by ingestion of Avitrol which is widely used in New York for pigeon control.

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.