Epidemiology of tick-borne encephalitis in Poland.

Tick-borne encephalitis are connected with existence of natural foci in environment, where virus circulation between natural host (rodents, wood mammals) and virus vectors does occur independently from humans. In Poland the first confirmed cases of tick-borne encephalitis occurred in following voivodships: białostockie, olsztyńskie, opolskie in 1948-1952. Between 1970 and 1993-816 cases of tick-borne encephalitis have been reported and annual morbidity has been from 0.01 to 0.6/100,000. In 1993 a sharp 30 fold-increase of reported cases occurred in comparison with previous year. In this year 249 cases were reported were reported and 94% of them and serological confirmation. Most of them were notified in following voivodships: białostockie, opolskie, ostrołeckie. In 1994-181 cases were reported mainly from endemic areas in the north-eastern territories of Poland.