Abstract
Since 2011 (summer/fall) a "new" ulcerative dermatitis disease syndrome of unknown etiology has been observed in ice seals (ringed, bearded, spotted, ribbon)1 and Pacific Walrus2 in Northern Alaska. Since July 2011, nearly 300 seals have been reported in Alaska. Additional cases have been reported from Chukotka, Russia (ice seals and walrus) and the Northwest Territory (NWT), Canada (ice seals). Ice seals and Pacific walruses are key species within the Arctic Ecosystem and an essential marine subsistence resource for Native communities throughout the Arctic. Thus food safety and food security aspects are integral components of this emerging Arctic marine mammal disease event. In response to the disease event a large scale trans-boundary interdisciplinary disease investigative team joining Native hunters from Alaska, Chuktoka, NWT and scientists (USA and international) was assembled. As of yet no specific cause has been identified, although numerous bacteria and viruses known to affect marine mammals have been ruled out. The disease is characterized by a variety of skin associated lesions (ulcers/erosion) with body site specific distribution (eyes; snout; hind flippers; tail, trunk) for ice seals and a more generalized distribution for Pacific walrus. For ice seals skin lesions are often associated with patchy hair loss and/or delayed molt; however a number of ice seals, in particular bearded and spotted seals have only presented with patchy to generalized hair loss with few to no skin lesions at all. All age classes have been affected in ice seals. For Pacific walrus sub-adults and calves appear primarily affected. Affected ice seals displayed uncommon behaviors such as unusual approachability, lethargy, and increased tendency for hauling out on land. In some animals respiratory signs are prominent. Gross pathological and histopathological findings indicate significant pathologic involvement of lung, liver, the immune system, and the skin associated vascular bed. The latter lesions are hypothesized to be the primary cause for the observed skin lesions. There is some mortality associated with the disease syndrome, however at this time we do not have enough epidemiological data to assess disease burden and develop reliable baseline estimates for ulcerative dermatitis disease syndrome associated mortalities among ice seal and Pacific walrus populations. Based on the overall positive spring and fall ice seal and walrus harvest (2012) reports which mostly indicated healthy and normal seals/walruses and the low numbers of observed stranding events (no live animals observed which is in stark contrast to 2011) in the North Slope and Bering Strait regions the disease event may have come to an end. A concise and brief summary of 2011–2012 case material including case definitions, geographic and temporal trends, case demographics, and the updated proposed Tier II action plan will be presented. In addition outcomes and recommendations based on an After-Action Review of the investigation highlighting the Alaskan Perspective will be summarized.
Acknowledgements
We especially thank North Slope Borough and Bering Strait Native subsistence hunters for their extraordinary support in field response and disease surveillance. The authors also wish to thank all the Working Group on Marine Mammal Unusual Mortality Events members and associated national and international investigative team members, and these are many, for their technical expertise and insightful guidance in this ALASKA disease investigation. Funding for the diagnostic sample work up and analysis was supported through NOAA/NMFS Unusual Mortality Event Fund and Emergency funds from NOAA/NMFS John H. Prescott Emergency Marine Mammal Rescue Assistance Grant Program (NSB-DWM, AVPS) as well as in kind contributions by the North Slope Borough, Department of Wildlife Management; Center for Infection and Immunity, Mailman School of Public Health, Columbia University, New York, NY 10032, USA, (Cadhla Firth); the Animal Health Center, Abbotsford, Canada, (Stephen Raverty); and the Department of Fisheries and Oceans Canada, Winnipeg, MB R3T 2N6, Canada (Ole Nielsen).
*Presenting author
Literature Cited
1. C. Goertz (Eds). 2012. Proceedings of the Arctic Pinniped Disease Investigation Workshop Alaska Marine Science Symposium Wednesday, Jan 18th, Anchorage, Alaska.
2. 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.