Abstract

Topic: Physiology, diseases and genetics

77 years of moose disease surveillance at the Swedish Veterinary Agency

Erik Olof Ågren¹, Karin Olofsson-Sannö¹, Jonas Malmsten², Gustav Averhed¹, Caroline Bröjer¹, Dolores Gavier-Widén¹, Gete Hestvik¹, Aleksija Neimanis¹, Elina Thorsson¹, Henrik Uhlhorn¹, Torsten Mörner³

Dept of Pathology and Wildlife Diseases, Swedish Veterinary Agency, 751 89 Uppsala, Sweden
Viltkonsult Jonas Malmsten AB Mörbytorpsvägen 303 18684 Vallentuna, Sweden
Viltvet veterinärservice AB, Sältlösavägen 1, 197 93 Bro, Sweden

The systematic wildlife disease surveillance in Sweden started in 1948 at the present Swedish Veterinary Agency (SVA). Initially financed by the Swedish Association for Hunting and Wildlife Management, veterinary pathologist Karl Borg pioneered this work, with focus on game animals. Health and disease aspects of moose has been and still is of highest importance for the hunting community and for the symbolic value moose has for Sweden. Management of the moose population is mainly done with hunting quotas. Disease as a cause of mortality in Swedish moose is low compared to hunting, followed by traffic-related mortality. But, when unusual mortality events or disease outbreaks occur, there is always concern for the moose population, and possible effects on the traditional moose hunt. The long-term disease surveillance at SVA has provided data for both causes of death and findings of new diseases by necropsies and ancillary testing of fallen moose (i.e. found dead or euthanized sick animals). Targeted surveillance projects have been used to screen the moose population for specific diseases, where sampling of hunter harvested moose has been useful. Over 11,400 moose have been examined as full carcasses, parts of carcasses or tissue samples submitted to SVA over 77 years. Examples of diseases or syndromes found and studied include Moose Wasting Syndrome, Chronic wasting disease, ethmoidal tumours, fibromas, deer ked infestation, hair-loss syndrome, nasal bots, chronic colitis, chronic ulcerative dermatitis, anaplasmosis, heavy metal contamination, stress-related mortality, neonatal calf mortality, and age-related changes such as cataracts and dental attrition. Odd or unusual diseases, such as ergotism, kyphosis, and hermaphroditism are also documented in this systematic surveillance. Apart from the diagnoses registered, the routine tissue samples taken at necropsy and stored in the SVA biobank, compiles into an invaluable collection of frozen tissues accompanied with animal data, all available for future retrospective research. An interdisciplinary approach and research collaboration with e.g. ecologists and wildlife managers is also needed to better use and understand the collected necropsy data and how it relates to changes in factors such as moose population density, or long-term changes in habitat or climate.