Some epidemiological data on TBE and Lyme borreliosis in Croatia

TEE in Croatia was first discovered in 1953 but its mandatory reporting, as a distinct nosological entity, was instituted in 1987. Data presented here concern the 1989-1998 decade. During this period a total of 500 cases of T EE was recorded, ranging from 23 (1990) to 87 (1994) per year, with an aver age of 50 cases annually. There is only one natural focus in the northern p art of: the country, between the rivers Sava and Drava. Alleged cases of TE E, as occurring out of the focus (Zadar and Pula), have not been certified. The seasonal distribution of TEE cases is typical, most cases occurring fr om May to July (75%). As for the age distribution of TBE, a substantial ris e is seen after the age of 20, only some 3% of cases occurring in children younger than 10 years. The first documented cases of human Lyme borreliosis in Croatia were published in 1986, its official compulsory reporting start ing in 1991. Since then 1464 cases were recorded with an annual average of some 150 cases, varying from 93 (1992) up to 335 (1996). The age distributi on is somewhat different from TBE, since the age group 0-9 years recruits 2 0% of ail cases. Nevertheless, most of the diseased are of adult age. About 92% of the cases occur between May and August. The disease occurs mostly i n the inland, above the 45th parallel, and only sporadically on the Adriati c coast.