Their findings are the first epidemiological data reported on the current outbreak of PDV, which was first detected in May 2002 when large numbers of dead seals were reported in Demark. The previous outbreak in 1988 was the largest such event in any marine mammal population.
The authors used mathematical models to compare the 2002 findings to the 1988 outbreak, and predict the 2002 event will have similar impacts on the harbour seal population. As many as 10,000 seals will die from PDV in 2002 in Denmark and Sweden alone. They used this information to explore how future seal plague outbreaks may affect population dynamics.
"This is, to our knowledge, the first study where the consequences of PDV outbreaks have been evaluated in terms of quasi-extinction," the authors say. "The risk of a catastrophic decline of the population is small, but other factors, like hunting, will increase that risk, as will more frequent PDV outbreaks."
The study was funded by the Swedish Environmental Protection Agency, US. Environmental Protection Agency, Oscar and Lili Lamm Research Foundation, Swedish Foundation for International Cooperation in Research and Higher Education, and the Helge Axson Johnson Research Foundation.