Species identification of ticks collected in Skåne county and their role in the epidemiology of tick-borne Encephalitis (TBEV)

Abstract: Skåne is the southernmost county of Sweden where new tick species could become established due to the topography with milder climatic conditions and the geographical bordering with northern continental Europe. Ticks also play an important role as vectors and transmitter of tick-borne encephalitis, a viral disease caused by tick-borne encephalitis virus (TBEV), for which the incidence of human cases increased twice during 2011-2013 and 2014-2017 in Skåne county. In this study ticks (n=1000), either collected from five different host species (domestic dog, domestic cat, roe deer, fallow deer and moose) or questing ticks collected by flagging method during year 2011-2016 were identified at species level using morphological keys. The result showed that all but one ticks (n=999) were identified as common hard tick species Ixodes ricinus (adult females; n=613, adult males; n=190 and nymphs; n=196) and one tick found on one individual domestic cat (Felis catus) was identified as an adult female of Ixodes hexagonus. In order to assess if TBEV has been circulating in Skåne during the years of tick collection, the study also investigated the occurrence of TBEV in the same ticks samples using Real-Time PCR. The result showed that no TBEV positive ticks were found in the analyzed specimens.