Small mammal trapping and sampling
Small mammals were trapped from 2012 to 2014 five times per year, in mid-April and in each first week of June, July, September and October. The trapping grid consisted of 196 live-traps (14 X 14 Uggland special nr. 3, Grahnab, Sweden) set at 15 m intervals, covering a total area of 3.2 ha. For each session, traps were set for three consecutive nights and baited with carrots and sunflower seeds. Trapped rodents were individually marked with a transponder (Vétérissimo Mini RWI-I, Vethica, France). Blood samples were taken once per session through the retro-orbital sinus. Species, body mass, sex and tick presence were recorded and then the animals were released at the point of capture. We used the minimum value of weight observed during a second capture session to define the threshold value below which an individual was considered juvenile. Accordingly, individuals weighting less than 14 g for M. glareolus and 16 g for A. flavicollis were considered juveniles. From April 2012 to July 2013, all the ticks found on rodents were collected. In June and July 2012, given the high number of small rodents captured, although all the animals were subject to blood sampling and examined for tick presence, we only counted and collected the ticks of a number of randomly-chosen animals infested by ticks. All the ticks and blood samples were kept at +4°C until brought back to the laboratory. There, the blood clot was gently detached from the bottom of the Eppendorf tube before being centrifuged at 5000 rpm for 5 min and the serum obtained was stored at -20°C until tested for the presence of TBEV antibodies. Larvae were identified at genus level and nymphs/adults at species level based on their morphology using appropriate keys and descriptions (Pérez‐Eid, 2007). All the ticks were washed in 70% ethanol, rinsed twice in distilled water, dried, and stored at -80°C until tested for TBEV