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


CONCLUSIONS
In a high-risk population, there was evidence of exposure to 5 tick-borne pathogens; however, many infections were asymptomatic, and coinfections were rare.
Hilton
E
E
North Shore-Long Island Jewish Health System, Division of Clinical Research, The Long Island Campus for the Albert Einstein College of Medicine, New Hyde Park, New York, USA.
DeVoti
J
J
Benach
J L
JL
Halluska
M L
ML
White
D J
DJ
Paxton
H
H
Dumler
J S
JS
D001404:Babesiosis / Q000453:epidemiology / Q000276:immunology; D015153:Blotting, Western; D016873:Ehrlichiosis / Q000453:epidemiology / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008193:Lyme Disease / Q000453:epidemiology / Q000276:immunology; D008297:Male; D009511:New England / Q000453:epidemiology; D012306:Risk; D012373:Rocky Mountain Spotted Fever / Q000453:epidemiology / Q000276:immunology; D016036:Seroepidemiologic Studies; D017282:Tick-Borne Diseases / Q000453:epidemiology* / Q000276:immunology*