PREVALENCE OF TICK-BORNE ENCEPHALITIS AND LYME BORRELIOSIS IN A DEFINED SWEDISH POPULATION

Sera from 346 individuals living on Lisö an area south of Stockholm, endemic for tick-borne encephalitis (THE) and Lyme borreliosis, were tested for antibody activity to TBE-virus (TBEV) and Borrelia burgdorferi, using a sonicate antigen, by haemagglutination-inhibition and ELISA, respectively. 10/346 (3% individuals had a history of previous serologically confirmed TBE with encephalitic symptoms, and 33/346 (10% had a history of previous erythema chronicum migrans (ECM). Four individuals (1% had been treated for neuroborreliosis and another 4 (1% for acrodermatitis chronics atrophicans (ACA). Antibodies to TBEV and B. burgdorferi were detected in 40/346 (12% and 89/346 (26% individuals, respectively. The seroprevalence of Lyme borreliosis increased with age, time spent on Lisö and number of reported tick-bites. For TBE there was a correlation between seropositivity and time spent on Lisö only. In sera from 50 healthy blood-donors, living in a non-endemic area, no antibody activity to TBEV could be detected and only 1/50 (2% had antibodies to borrelia. In sera from 150 age and sex matched control individuals, living in the city of Stockholm, antibody activity to TBEV and borrelia was found in 8/150 (5% and 13/150 (9% respectively. © 1990 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.