Small risk of developing symptomatic tick-borne diseases following a tick bite in the Netherlands

• Main Authors: Hofhuis Agnetha, Brandenburg Afke H, van der Giessen Joke WB, Reimerink Johan H, Fonville Manoj, Jacobs Jac J, Swart Arno, Tijsse-Klasen Ellen, Sprong Hein
• Format: Article
• Language: English
• Published: BMC 2011-02-01
• Series: Parasites & Vectors
• Online Access: http://www.parasitesandvectors.com/content/4/1/17

<p>Abstract</p> <p>Background</p> <p>In The Netherlands, the incidence of Lyme borreliosis is on the rise. Besides its causative agent, <it>Borrelia burgdorferi </it>s.l., other potential pathogens like <it>Rickettsia</it>, <it>Babesia </it>and <it>Ehrlichia </it>species are present in <it>Ixodes ricinus </it>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.</p> <p>Results</p> <p>In total, 297 <it>Ixodes ricinus </it>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 <it>Borrelia burgdorferi s.l.</it>, <it>Rickettsia </it>spp., <it>Babesia </it>spp. or <it>Ehrlichia/Anaplasma </it>spp.. Sixteen percent of the collected ticks were positive for <it>Borrelia burgdorferi s.l</it>., 19% for <it>Rickettsia </it>spp., 12% for <it>Ehrlichia</it>/<it>Anaplasma </it>spp. and 10% for <it>Babesia </it>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 <it>Borrelia afzelii</it>, and having 'any symptoms' was positively associated with attachment duration.</p> <p>Conclusion</p> <p>The risk of contracting acute Lyme borreliosis, rickettsiosis, babesiosis or ehrlichiosis from a single tick bite was <1% in this study population.</p>