Seroprevalence of Lyme disease in southwest Asturias.

INTRODUCTION

To correctly interpret the serological markers of Lyme disease, it is very important to determine the region's infection rate. The aim of this study was to ascertain the prevalence of specific antibodies against Borrelia burgdorferi in a rural district in northern Spain.

METHODS

The presence of IgG antibodies against B. burgdorferi was determined by qualitative enzyme immunoassay in the serum of 1,432 people divided into 3groups: 316 blood donors, 432 individuals who attended the hospital without infection and 684 for whom Lyme serology testing was specifically requested as part of a differential diagnosis. In the latter group, the presence or absence of an occupational risk factor was recorded.

RESULTS

Antibodies against B. burgdorferi were detected in 189 individuals (13.2%): 16 (5.1%) in the blood donors group, 62 (14.4%) in subjects who attended hospital without infection and 111 (16.2%) in subjects in whom a differential diagnosis of Lyme disease was requested (p < 0.0001). In subjects with an occupational risk factor, the prevalence was 23.5%, peaking at 45.8% in men over 65 years.

CONCLUSION

Our study showed a high prevalence of antibodies against B. burgdorferi and higher than that seen in other areas with similar characteristics in Spain. However, our results are similar to those published from other European regions. The prevalence in the blood donors group was lower than that observed in the other groups. Older age, the male gender and occupational risks were associated with a higher prevalence of Lyme disease.