Two-year survey of the incidence of Lyme borreliosis and tick-borne encephalitis in a high-risk population in Sweden.
A survey was made over a two-year period (September 1987 to August 1989) of a population living in an area endemic for Lyme borreliosis and tick-borne encephalitis in Sweden. For each patient a blood sample was collected and a questionnaire completed annually. All sera were tested for an antibody response to Borrelia burgdorferi in an EIA using sonicated antigen and for an antibody response to the tick-borne encephalitis virus using an EIA and a haemagglutination inhibition test. Antibodies to Borrelia burgdorferi and tick-borne encephalitis virus were detected in 89 (25.7%) and 40 (11.6%) respectively of 346 samples collected in August 1987. In the first year of the study 14 of 303 subjects (4.6%) developed Lyme borreliosis and in the second year 9 of 277 subjects (3.2%). A significant increase in the antibody titre for Borrelia burgdorferi was seen in 14 of 303 (4.6%) subjects in the first year and 8 of 277 (2.9%) subjects in the second year. An earlier episode of Lyme borreliosis or an elevated antibody titre did not seem to protect against reinfection. One case of tick-borne encephalitis was seen each year. Seroconversion for tick-borne encephalitis virus was found in 3 of 258 (1.2%) subjects in the first year and 5 of 211 (2.4%) in the second year, excluding subjects who had undergone successful immunisation or had earlier been hospitalised for tick-borne encephalitis. The study thus demonstrated a high yearly incidence of tick-borne infections in a population at risk.
Gustafson
R
R
Department of Infectious Diseases, Karolinska Institute, Huddinge University Hospital, Sweden.
Svenungsson
B
B
Forsgren
M
M
Gardulf
A
A
Granström
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D001096:Arachnid Vectors; D001733:Bites and Stings / Q000453:epidemiology; D015748:Borrelia burgdorferi Group / Q000276:immunology / Q000302:isolation & purification; D002648:Child; D004675:Encephalitis, Tick-Borne / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control; D015787:Erythema Chronicum Migrans / Q000453:epidemiology; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D015994:Incidence; D008193:Lyme Disease / Q000453:epidemiology* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology; D013987:Ticks / Q000382:microbiology; D014611:Vaccination; D014765:Viral Vaccines
D000907:Antibodies, Bacterial; D000914:Antibodies, Viral; D014765:Viral Vaccines