Résumé
In Europe, ticks can transmit many zoonotic pathogens to humans including bacteria of the Borrelia Burgdorferi (s.l.) complex responsible for Lyme borreliosis (LB). In the Auvergne Rhône-Alpes region (southeastern France), the incidence rate of LB was estimated 156 cases per 100,000 inhabitants. While the risk of exposure to tick bites is well known in forests and rural areas, it remains unclear in urban and peri-urban green spaces, which are however very frequented by human beings.Two urban parks and one peri-urban park were subject to acarological surveillance from 2019 to 2022 using the dragging method. A rural site was used as control. In each park, one hundred 10 m2 transects were chosen at random in closed (forests, woods), intermediate (edges) and open (lawns, meadows) environments. From 2020 to 2022, rodents were also captured with traps twice a year in one urban and one periurban park in the context of the BioRodDis BiodivERsA project. Ticks were stored in 70% ethanol for subsequent morphological identification. DNA extracted from ticks and ears from rodents and were screened for Borrelia burgdorferi sl by qPCR. In 2021 and 2022, new sites distributed along a western, northern ans southern ecological corridors from the outskirts to the center of the city were also monitored for ticks.The acarological surveillance confirms the presence of Ixodes ricinus ticks in urban and periurban sites respectively with significantly higher abundances in periurban green spaces. It shows that areas under forest cover and forest edges are the most at risk of tick exposure. Molecular analyses detected bacteria of the Borrelia burgdorferi sl complex in ticks in almost all periurban green space. Only one tick was found infected in the urban environments explored. Similar tendencies were obtained for prevalences in rodents.The study suggests that the risk of Ixodes ricinus and Borrelia burgdorferi sl exposure is possible even in the urban area but significantly lower than in peri-urban and rural environments. The surveillance should be extended to other sites, animals and humans to improve knowledge on risk exposure to ticks and determine drivers for ticks presence and abundance in urbanized environments.