, Volume 5, Issue 2, pp 213–223 | Cite as

Fatal Pneumonia Epizootic in Musk Ox (Ovibos moschatus) in a Period of Extraordinary Weather Conditions

  • Bjørnar YtrehusEmail author
  • Tord Bretten
  • Bjarne Bergsjø
  • Ketil Isaksen


The musk ox is adapted to extreme cold and regarded as vulnerable to the impacts of climate change. Population decline is proposed to occur due to changes in forage availability, insect harassment, parasite load, and habitat availability, while the possible role of infectious diseases has not been emphasized. The goal of the present article is to describe an outbreak of fatal pasteurellosis that occurred in the introduced musk ox population of Dovrefjell, Norway in 2006, causing the death of a large proportion of the animals. The epizootic coincided with extraordinary warm and humid weather, conditions that often are associated with outbreaks of pasteurellosis. The description is based on long series of data from the surveillance of the musk ox population, weather data from a closely located meteorological station, and pathoanatomical investigation of the diseased animals. It is concluded that the weather conditions likely were the decisive factors for the outbreak. It is suggested that such epizootics may occur increasingly among cold-adapted animals if global warming results in increased occurrence of heat waves and associated extreme weather events, thereby causing population declines and possibly extinctions.


musk ox Arctic climate change global warming pasteurellosis disease 



The authors thank mountain rangers Ingolf Røtvei, Jon Nørstebø, and Trond Toldnes, as well as Marthe Opland at Section for Wildlife Diseases, NVI, for the excellent technical assistance in the field and laboratory. In addition, we are grateful to Rebecca K. Davidson and Turid Vikøren at Section for Wildlife Diseases, NVI, and Øyvind Nordli at Climatology Division, NMI, for their helpful comments with the manuscript; we also thank Attila Tarpai at Section for Epidemiology, NVI, for his help with Figure 1. This report was supported by the National Health Surveillance Program for Cervids.


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Copyright information

© International Association for Ecology and Health 2008

Authors and Affiliations

  • Bjørnar Ytrehus
    • 1
    Email author
  • Tord Bretten
    • 2
  • Bjarne Bergsjø
    • 3
  • Ketil Isaksen
    • 4
  1. 1.Section for Wildlife DiseasesNational Veterinary InstituteOsloNorway
  2. 2.Oppdal BygdealmenningOppdalNorway
  3. 3.Section for BacteriologyNational Veterinary InstituteOsloNorway
  4. 4.Climatology DivisionNorwegian Meteorological InstituteOsloNorway

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