SEROPREVALENCE OF LYME-DISEASE IN WESTERN FRANCE

The seroprevalence of Lyme disease was studied in the Loire area which is located in western France. Three hundred and seventy-four blood do nors and patients hospitalized for another condition had serum samples taken and answered a confidential epidemiological questionnaire. Sera were tested by indirect immunofluorescence and hemagglutination. Anti body titers greater-than-or-equal-to 1/128 by IF and/or greater-than-o r-equal-to 1/200 by hemagglutination were found in 33.7 % of tested su bjects; 12.6 % of sera were positive by IF only, 10.7 % were positive by hemagglutination only, and 10.4 % were positive by both techniques. A positive serologic test was not significantly correlated with sex, age, site of residence, occupation, exposure to rural environments, or a history of insect bites. These findings suggest that asymptomatic B orrelia burgdorferi occurs in western France. Problems with the specif icity and sensitivity of serologic tests are discussed.