Environmental and ecological potential for enzootic cycles of Puumala hantavirus in Great Britain.

Puumala virus (PUUV) is a zoonotic rodent-borne hantavirus in continental Europe. Its reservoir host, the bank vole (Myodes glareolus), is ubiquitous in Great Britain (GB); however, there has been no reported incidence of virus in either animals or humans. In northwest Europe, increases in bank vole numbers, stimulated by increases in production of beech/oak crops (mast), are associated with outbreaks of nephropathia epidemica (NE) in humans. These so-called 'mast years' are determined by sequential climatic events. This paper investigates the contribution of a number of ecological and environmental factors driving outbreaks of PUUV in northwest Europe and assesses whether such factors might also permit enzootic PUUV circulation in GB. Analysis of GB climate data, using regression models, confirms that mast years in GB are stimulated, and can be predicted, by the same climatic events as mast years in PUUV-endemic regions of northwest Europe. A number of other possible non-climatic constraints on enzootic cycles are discussed.