Development of an integrated geo-epidemiological system for the assessment of occupational risk of tick-borne pathogens.

INTRODUCTION: In europe, ticks are one of the most important vectors of human and animal infectious diseases. Certain occupational categories are at increased risk of exposure to potentially infected ticks. The aim of this project was to perform a risk assessment of tick-borne pathogens (TbPs) among those workers most exposed to tick bites in the “Triveneto” area. MATERIALS AND METHODS: Three categories of data were collected: i) presence and abundance of tick species in past and recent times; ii) occurrence of TbPs in ticks; iii) environmental and meteorological data. These data were used to model the ecological niche of ticks as to predict their habitat suitability range and to build risk maps for TbP exposure. Ticks were collected by dragging in 2020-2021 in veneto and friuli venezia Giulia regions; these data were integrated with historical tick collections (samplings of 2006-2017 period). after morphological tick identification, molecular tests were performed for Borrelia, Rickettsia, and Anaplasma, Babesia/Theileria species, Tbe and CChf viruses in pooled (larvae and nymphs) or adult ticks. estimates of pooled prevalence (ePP) and confidence limits 95% (Cl) for variable pool size w ere calculated. blood sam ples from transhu mant sheep herds located in historical Tb P detection areas were serologically screened. TbPs data in ticks were modeled with the environmental and meteorological data using maxent and Glms to define infected ticks’ ecological niche, which was subsequently studied in relation to pathogen detection in animal samples. a dedicated website to report information on the risk of infections and prevention measures is in progress. RESULTS AND CONCLUSIONS: In 2020-2021, 43 tick samplings were conducted and 2403 ticks (all stage s) w ere collected; of these, 1388 were pooled (175 total pools) and screened for TbPs. a first scree ning fo r TbPs detected 5 positive samples for Borrelia spp. (ePP=0.3 6; C l=0.13-0.78), 48 for Rickettsia spp. (ePP=4.03; Cl=3.01-5.26), 20 for A. phagocitophylum (ePP=1.53; Cl=0.96-2.30) and 30 for Babesia/Theileria spp. (ePP=2.27; Cl=1.56-3.18). fourteen samples presented co-infections or multiple TbPs detections. further tests are ongoing to confirm the TbPs screening results. no positive samples were detected for CChfv and Tbev. To date, 463 sera from domestic and wild ruminants have been collected but not tested for TbPs yet. a complete environmental/meteorological and TbP database was created and preliminary ecological niche analyses showed a relatively broad habitat suitability range for Anaplasma (mostl y defined by autumnal veg etation index), whereas the narrowe st range was observed for Borrelia (mostly defined by coldest temperature and altitude). website-building activities and information development have started. further spatial analyses are ongoing and the last step will be to develop a risk map of TbP exposure for workers.