The number of ticks, members of the acarids, is increasing in the Finnish nature, and the risk of tick-borne infections has therefore increased as well. The incidence of Lyme borreliosis and tick-borne encephalitis has also increased over the past few years. Possible recently discovered tick-borne infectious organisms include Borrelia miyamotoi and Anaplasma phagocytophilum bacteria and the babesia protozoon. Although infections caused by these microorganism are presumed to be rare in Finland, they should be considered in the differential, diagnosis of a febrile patient following a detected or suspected tick bite.