title: Prospective study on the incidence of infection by Borrelia burgdorferi sensu lato after a tick bite in a highly endemic area of Switzerland.
abstract: The periurban forest of Neuchâtel (Switzerland) is a high-risk area for Lyme Borreliosis, due to a high density of infected Ixodes ricinus ticks. In this study, we evaluated the risk of subclinical (seroconversion) and clinical infection after a tick bite in Neuchâtel inhabitants from 2003 to 2005. Inhabitants have been invited, through media, to visit a physician after a tick bite. A questionnaire was filled out and two blood samples were taken at 8-week interval. EIA screening tests for IgM and IgG (IMX system, Abbott) were applied for paired sera. In case of a change in antibody titres between both samples, a homemade Western-blot using Borrelia afzelii, B. burgdorferi sensu stricto and B. garinii as antigens was performed. Participants were included into two groups. Group one included asymptomatic participants (n=255). Among them, nine (3.5%) seroconverted with seroconversion rates varying between 6.8% in 2003, 2.1% in 2004 and 2.3% in 2005. Participants who developed clinical symptoms of LB were included into group two (n=14). Erythema migrans (EM) was reported in 5.2% of participants (5.2%), varying between 7.5% in 2003, 5% in 2004 and 3.4% in 2005. Ticks obtained from 186 participants were examined for B. burgdorferi infection by PCR/Reverse Line Blotting, and by Real Time PCR and tick attachment duration was estimated. Among I. ricinus ticks collected from participants, 32.8% were infected by B. burgdorferi sensu lato. B. afzelii predominated among these ticks. Globally, 65.9% of nymphs remained attached for more than 24h whereas only 38.3% of female ticks remained attached for more than 24h. We observed that 6.6% and 2.4% of participants bitten by infected and uninfected ticks, respectively, developed EM.
authors: Institut de Biologie, Laboratoire d'Eco-Epidémiologie, Université de Neuchâtel, 2000 Neuchâtel, Switzerland.
authors: Delphine
authors: D
authors: Huegli
authors: Jacqueline
authors: J
authors: Moret
authors: Olivier
authors: O
authors: Rais
authors: Yves
authors: Y
authors: Moosmann
authors: Philippe
authors: P
authors: Erard
authors: Raffaele
authors: R
authors: Malinverni
authors: Lise
authors: L
authors: Gern
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D001096:Arachnid Vectors / Q000382:microbiology* / Q000502:physiology; D001733:Bites and Stings / Q000276:immunology / Q000382:microbiology; D015153:Blotting, Western; D025065:Borrelia burgdorferi / Q000302:isolation & purification*; D015748:Borrelia burgdorferi Group / Q000302:isolation & purification*; D002648:Child; D002675:Child, Preschool; D004269:DNA, Bacterial / Q000032:analysis; D005260:Female; D005929:Glossitis, Benign Migratory / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis / Q000276:immunology; D007075:Immunoglobulin M / Q000032:analysis / Q000276:immunology; D015994:Incidence; D007223:Infant; D018884:Ixodes / Q000382:microbiology* / Q000502:physiology; D008193:Lyme Disease / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology* / Q000276:immunology / Q000382:microbiology / Q000635:transmission; D008297:Male; D008875:Middle Aged; D009758:Nymph / Q000382:microbiology* / Q000502:physiology; D011446:Prospective Studies; D060888:Real-Time Polymerase Chain Reaction; D012698:Serologic Tests; D013557:Switzerland / Q000453:epidemiology
chemical_list: D004269:DNA, Bacterial; D007074:Immunoglobulin G; D007075:Immunoglobulin M