Gert E. Olsson*†
, Neil White*†, Clas Ahlm†, Fredrik Elgh†‡§, Ann-Christin Verlemyr†, Per Juto†, and R. Thomas Palo*†
Figure 1. Mean (± SE) trap indices of bank voles in all six sites during a 5-year sampling period in northern Sweden. Trap indices represent success in sampling effort as numbers of voles captured per 100 trap nights. Lower, shaded part of the bars represents trap indices of Puumula virus (PUUV)-seropositive bank voles, and the upper part represents PUUV-seronegative voles at each sampling occasion.