a1 Department of Biology, Evolutionary Ecology group, University of Antwerp, Antwerp, Belgium
a2 Comptoir Wallon des Matériels Forestiers de Reproduction, Marche-en-Famenne, Belgium
a3 Research Laboratory of Vector-Borne Diseases, Queen Astrid Military Hospital, Brussels, Belgium
a4 Scientific Institute of Public Health, Epidemiology Unit, Brussels, Belgium
a5 Danish Pest Infestation Laboratory, Department of Integrated Pest Management, Faculty of Agricultural Sciences, University of Aarhus, Denmark
Recently, human cases of nephropathia epidemica (NE) due to Puumala virus infection in Europe have increased. Following the hypothesis that high reservoir host abundance induces higher transmission rates to humans, explanations for this altered epidemiology must be sought in factors that cause bank vole (Myodes glareolus) abundance peaks. In Western Europe, these abundance peaks are often related to high tree seed production, which is supposedly triggered by specific weather conditions. We evaluated the relationship between tree seed production, climate and NE incidence in Belgium and show that NE epidemics are indeed preceded by abundant tree seed production. Moreover, a direct link between climate and NE incidence is found. High summer and autumn temperatures, 2 years and 1 year respectively before NE occurrence, relate to high NE incidence. This enables early forecasting of NE outbreaks. Since future climate change scenarios predict higher temperatures in Europe, we should regard Puumala virus as an increasing health threat.
(Accepted June 02 2008)
(Online publication July 07 2008)