Investigation of a Pinniped Skin Disease Outbreak in the Arctic and Bering Sea Regions
IAAAM 2013
Tristan L. Burgess1*+; Kathy Burek-Huntington2; Raphaela Stimmelmayr3; Gay Sheffield4; Joel Garlich Miller5; Stephen Raverty6; Kate Savage7; Michelle Barbieri8,11; Cadhla Firth9; Ole Nielsen10; Deborah Fauquier11; Teresa K. Rowles11
1Wildlife Health Center, School of Veterinary Medicine, University of California, Davis, California, 95616, USA; 2Alaska Veterinary Pathology Services, Eagle River, Alaska, 99577, USA; 3Department of Wildlife Management, North Slope borough, Barrow, Alaska, 99723, USA 4University of Alaska Fairbanks, Marine Advisory Program, Nome, Alaska, 99762, USA; 5U.S. Fish and Wildlife Service, Marine Mammals Management, Anchorage, Alaska 99503, USA; 6Animal Health Centre, Ministry of Agriculture, Abbotsford, British Columbia V3G2M3, Canada; 7Alaska Regional Office, National Marine Fisheries Service, Juneau, Alaska, 99802, USA; 8The Marine Mammal Center, Sausalito, California, 94965,USA; 9Center for Infection and Immunity, Mailman School of Public Health, Columbia University, New York, New York, 10032, USA; 10Department of Fisheries and Oceans Canada, Winnipeg, MB R3T 2N6, Canada; 11Office of Protected Resources, National Marine Fisheries Service, Silver Spring, Maryland, 20910, USA
Abstract
Sporadic cases of alopecia and retained pelage have previously been reported in arctic phocids.3 Since July 2011 nearly 300 seals with skin disease have been reported in the Bering Strait region and North Slope Borough, Alaska, USA as well as Chukotka, Russia, and Northwest Territories, Canada. Affected species were ringed seal (Phoca hispida), bearded seal (Erignathus barbatus) and spotted seal (Phoca larga).2 In September 2011, an estimated 6% of Pacific walruses (Odobenus rosmarus) hauled out at Point Lay, Alaska were observed to have skin lesions.1 Affected walruses have also been reported in Chukotka. Based upon these findings, NOAA and USFWS declared an Unusual Mortality Event (UME) for pinnipeds and walruses in December 2011.
Cases have been designated UME-1 for those with alopecia only, and UME-2 for those with alopecia in conjunction with skin lesions. Some of the latter animals were weak and lethargic with signs of systemic illness. Seventy seals received a full necropsy and histopathology examination, resulting in 29 UME-2 cases, eight UME-1 cases, 14 non-cases, and the balance non-diagnostic. Specimens from 15 walruses were examined, with 10 recorded as cases.
A descriptive analysis of skin lesions and their association with case status was undertaken to understand the etiology and guide future research. Sex was not associated with case status, and there was no age predilection, with all age classes represented among cases. Skin and mucosal lesions, as well as hepatitis, occurred more commonly in cases than non-cases, and several skin lesions tended to co-occur, rather than appear in isolation. Cardiac and respiratory lesions, though commonly observed, were not associated with case status, suggesting they were likely incidental findings. The most common pathogen, and the only one associated with lesions, was Streptococcus phocae; whether this organism represents an opportunistic infection or a part of the etiology is not known.
Acknowledgements
Dr. Tristan Burgess (Ph.D. candidate, UC Davis) received funding support from the NOAA/NMFS UME contingency fund; veterinary diagnostic sample work up and analysis was supported through NOAA/NMFS UME Contingency, NOAA/NMFS Emergency Prescott funds (North Slope Borough Department of Wildlife Management and Alaska Veterinary Pathology Services) and the Working Group for Marine Mammal Unusual Mortality Events. The ongoing Alaskan Pinniped Unusual Mortality Event investigation is a large-scale trans-boundary interdisciplinary disease investigative team joining Native subsistence hunters from Alaska, Chuktoka, Northwest Territories and scientists (USA and international). We especially thank North Slope Borough, and Bering Strait Native coastal communities, and the respective Alaska Native marine mammal co-management organizations including the Ice Seal Committee and Eskimo Walrus Commission for their dedication to field response and disease surveillance.
* Presenting author
+ Student presenter
Literature Cited
1. Garlich-Miller J (USFWS), Neakok W (Eskimo Walrus Commission), Stimmelmayr R (NSB Dept. Wildl. Mgt.). 2011. Field Report: Walrus Carcass Survey, Point Lay Alaska September 11–15, 2011. US Fish and Wildlife Service, Marine Mammals Management.
2. C. Goertz (Eds). 2012. Proceedings of the Arctic Pinniped Disease Investigation Workshop Alaska Marine Science Symposium Wednesday, Jan 18th.
3. McLaren IA. 1958. The biology of the ringed seal (Phoca hispida Schreber) in the eastern Canadian Arctic; Ottawa: Fisheries Research Board of Canada. 97 p.