Seroprevalence and seroconversion for tick-borne diseases in a high-risk population in the northeast United States

Am J Med. 1999 Apr;106(4):404-9. doi: 10.1016/s0002-9343(99)00046-7.


Purpose: To determine the prevalence of serologic reactivity, the 1-year incidence of seroconversion, and the frequency of multiple infections, and their associations with symptoms in a group of volunteers at high risk for tick-borne infections in New York state.

Methods: We performed a seroepidemiologic study of Lyme borreliosis, 2 of the ehrlichioses, Rocky Mountain spotted fever, and babesiosis among 671 participants who lived or worked in a high-risk area (mainly in eastern Long Island, New York) for tick-borne diseases. Sera were collected in the winters of 1994 and 1995. Signs and symptoms of tick-borne disease were monitored monthly by mail and telephone. Lyme borreliosis serologies were done by enzyme-linked immunosorbent assay and Western blot. Rocky Mountain spotted fever serologies were initially screened using Dip-S-Ticks, followed by specific indirect immunofluorescence. Ehrlichiosis serologies were determined by epifluorescent microscopy, as were antibodies to Babesia microti.

Results: Of the 671 participants, 88 (13%) had antibodies to > or = 1 tick-borne organisms, including 34 (5% of the total) with antibodies to Borrelia burgdorferi. Twenty-seven participants had evidence of exposure to B. burgdorferi at baseline. Seven participants (1%) seroconverted during the course of the study, 5 of whom were symptomatic for Lyme borreliosis. Antibodies to spotted fever group rickettsiae were seen in 28 participants (4%), 22 of whom were positive at baseline and 6 of whom seroconverted during the observation period. None of the seropositive patients had any symptoms or signs of infection. Twenty-four participants (3%) had serologic evidence of exposure to Ehrlichia (all but one to Ehrlichia equi); 5 (0.7%) seroconverted during the observation period, including 3 subjects who were asymptomatic. Antibodies to B. microti were seen in 7 participants (1%), including one asymptomatic seroconversion during the year of observation. There was evidence of possible dual infection in 5 patients.

Conclusion: In a high-risk population, there was evidence of exposure to 5 tick-borne pathogens; however, many infections were asymptomatic, and coinfections were rare.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Babesiosis / epidemiology
  • Babesiosis / immunology
  • Blotting, Western
  • Ehrlichiosis / epidemiology
  • Ehrlichiosis / immunology
  • Enzyme-Linked Immunosorbent Assay
  • False Positive Reactions
  • Female
  • Humans
  • Lyme Disease / epidemiology
  • Lyme Disease / immunology
  • Male
  • New England / epidemiology
  • Risk
  • Rocky Mountain Spotted Fever / epidemiology
  • Rocky Mountain Spotted Fever / immunology
  • Seroepidemiologic Studies
  • Tick-Borne Diseases / epidemiology*
  • Tick-Borne Diseases / immunology*