[Enzootic reservoir for new Ixodes ricinus-transmitted infections]

In the last decade new tick-transmitted zoonoses have emerged as threats to the public health in Europe. They are mostly due to infection by Borrelia burgdorferi s.I., Babesia divergens, B. microti and Ehrlichia sp. All these pathogens are transmitted by the rodent-feeding ticks of Ixodes persulcatus "complex". Also there is first serological information of coexistence of antibodies to B. burgdorferi, B. microti and Ehrlichia sp. in human exposured to these multiple tick-transmitted pathogens. Actually in Poland, the identification of the host species that act as zoonotical reservoir for these pathogens on which the competent vector becomes infected, is crucial to understand the dynamics of enzootic cycle of these pathogens. It is also important to assess the risk factor of infection in different habitats, especially in environmental condition where changing in farming system has left great land area under grassland or pasture, e.g. in Mazury Lakes District. Under such circumstances, susceptible rodent species, at least for two of these pathogens: B. micrnti and B. burgdorfeń s.l., increasingly became competent reservoirs. This aspect is currently receiving considerable attention in Europe.