title: Small risk of developing symptomatic tick-borne diseases following a tick bite in The Netherlands.
abstract: BACKGROUND
  In The Netherlands, the incidence of Lyme borreliosis is on the rise. Besides its causative agent, Borrelia burgdorferi s.l., other potential pathogens like Rickettsia, Babesia and Ehrlichia species are present in Ixodes ricinus ticks. The risk of disease associated with these microorganisms after tick-bites remains, however, largely unclear. A prospective study was performed to investigate how many persons with tick-bites develop localized or systemic symptoms and whether these are associated with tick-borne microorganisms.
  
  
  RESULTS
  In total, 297 Ixodes ricinus ticks were collected from 246 study participants who consulted a general practitioner on the island of Ameland for tick bites. Ticks were subjected to PCR to detect DNA of Borrelia burgdorferi s.l., Rickettsia spp., Babesia spp. or Ehrlichia/Anaplasma spp.. Sixteen percent of the collected ticks were positive for Borrelia burgdorferi s.l., 19% for Rickettsia spp., 12% for Ehrlichia/Anaplasma spp. and 10% for Babesia spp.. At least six months after the tick bite, study participants were interviewed on symptoms by means of a standard questionnaire. 14 out of 193 participants (8.3%) reported reddening at the bite site and 6 participants (4.1%) reported systemic symptoms. No association between symptoms and tick-borne microorganisms was found. Attachment duration ≥24 h was positively associated with reddening at the bite site and systemic symptoms. Using logistic regression techniques, reddening was positively correlated with presence of Borrelia afzelii, and having 'any symptoms' was positively associated with attachment duration.
  
  
  CONCLUSIONS
  The risk of contracting acute Lyme borreliosis, rickettsiosis, babesiosis or ehrlichiosis from a single tick bite was <1% in this study population.
authors.affiliation: Laboratory for Zoonoses and Environmental Microbiology, Centre for Infectious Disease Control Netherlands, National Institute for Public Health and Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Ellen
authors.initials: E
authors.lastname: Tijsse-Klasen
authors.forename: Jac J
authors.initials: JJ
authors.lastname: Jacobs
authors.forename: Arno
authors.initials: A
authors.lastname: Swart
authors.forename: Manoj
authors.initials: M
authors.lastname: Fonville
authors.forename: Johan H
authors.initials: JH
authors.lastname: Reimerink
authors.forename: Afke H
authors.initials: AH
authors.lastname: Brandenburg
authors.forename: Joke W B
authors.initials: JW
authors.lastname: van der Giessen
authors.forename: Agnetha
authors.initials: A
authors.lastname: Hofhuis
authors.forename: Hein
authors.initials: H
authors.lastname: Sprong
mesh_terms: D000818:Animals; D001403:Babesia / Q000235:genetics / Q000302:isolation & purification; D025065:Borrelia burgdorferi / Q000235:genetics / Q000302:isolation & purification; D004536:Ehrlichia / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D007299:Insect Bites and Stings / Q000150:complications*; D018884:Ixodes / Q000382:microbiology* / Q000469:parasitology*; D009426:Netherlands / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D012281:Rickettsia / Q000235:genetics / Q000302:isolation & purification; D018570:Risk Assessment; D017282:Tick-Borne Diseases / Q000453:epidemiology* / Q000382:microbiology / Q000469:parasitology