Tick-borne encephalitis virus, illustration. Tick-borne encephalitis virus can affect birds, rodents, ruminants and can also spread from animals to humans, mainly from dogs. Tick- borne encephalitis covers a range of illnesses ranging from a severe paralytic encephalitis, which occurs in Siberia and is transmitted by Ixodes persulcatus, to diseases such as meningitis, encephalitis and meningoencephalitis. A less paralytic encephalitis is found in central Europe and transmitted by Ixodes ricinus. Agricultural and forestry workers are most frequently affected, as the foci of infection are in and around forest areas, the vertebrate maintenance hosts being rodents and ground-living birds.