The prevalence and incidence of clinical and asymptomatic Lyme borreliosis in a population at risk

J Infect Dis. 1991 Feb;163(2):305-10. doi: 10.1093/infdis/163.2.305.


A past history of clinical Lyme borreliosis and the 6-month incidence of clinical and asymptomatic Lyme borreliosis was studied prospectively in a high-risk population. In the spring, blood samples were drawn from 950 Swiss orienteers, who also answered a questionnaire. IgG anti-Borrelia burgdorferi antibodies were detected by ELISA. Positive IgG antibodies were seen in 248 (26.1%), in contrast to 3.9%-6.0% in two groups of controls (n = 101). Of the orienteers, 1.9%-3.1% had a past history of definite or probable clinical Lyme borreliosis. Six months later a second blood sample was obtained from 755 participants, 558 (73.9%) of whom were seronegative initially; 45 (8.1%) had seroconverted from negative to positive. Only 1 (2.2%) developed clinical Lyme borreliosis. Among all participants, the 6-month incidence of clinical Lyme borreliosis was 0.8% (6/755) but was much higher (8.1%) for asymptomatic seroconversion (45/558). In conclusion, positive Lyme serology was common in Swiss orienteers, but clinical disease occurred infrequently.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Animals
  • Antibodies, Bacterial / blood*
  • Arachnid Vectors
  • Bites and Stings / complications
  • Borrelia burgdorferi Group / immunology*
  • Child
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Humans
  • Immunoglobulin G / analysis
  • Incidence
  • Lyme Disease / epidemiology*
  • Male
  • Middle Aged
  • Prevalence
  • Prospective Studies
  • Regression Analysis
  • Surveys and Questionnaires
  • Ticks


  • Antibodies, Bacterial
  • Immunoglobulin G