Tick bite and Lyme borreliosis risk at a recreational site in England

The risk of tick bite and Lyme borreliosis in a forested area in England wi th public access was studied over a two-year period. Tick infestation level s were high with more than 1000 members of the public reporting for tick re moval at a local clinic. Most of the attached ticks were nymphs (82%) and d istinct differences in anatomical sites of attachment were observed in chil dren and adults. Children sustained nymphal bites to the head, neck and axi lla region much more frequently than adults (48 vs. 10%), whereas adults we re bitten on the lower legs more frequently than children (46 vs. 9%). The vegetation was heavily infested with ticks and high numbers were particular ly associated with areas used by deer. The average density of nymphs collec ted from the vegetation was 14.1 per 10 m(2) (range 5.1-43.6). Infection ra tes of these nymphs determined by PCR and indirect IFA ranged from 5.2-17.0 %, and the genospecies Borrelia valaisiana and B. garinii were detected, su ggesting that birds may be important reservoir hosts in this area. It is es timated that, at the level of tick challenge observed here, at least 50 per sons per year may be bitten by infected ticks at this site. However, no cas es of Lyme borreliosis have been reported through the clinic follow-up proc edure, and sera from 19 forest workers were negative for antibody to B. bur gdorferi sensu lato. Despite the high challenge from tick bites, this parti cular recreational forest site poses a low risk of infection to the general public, and prophylactic antibiotic treatment or serological testing follo wing a bite is not justified.