Tick-Borne Infections: Results from a Prospective Observational Study from a Single Centre in Northern Italy.

BACKGROUND

Data on tick-borne diseases (TBDs) in Italy are fragmented. This study aimed to describe tick-borne pathogens (TBPs) and TBDs observed in a hospital in Italy and to assess the correlation between TBPs and human disease.

METHODS

A prospective observational study was conducted in a single hospital between March 2024 and January 2025. Inclusion criteria were: individuals ≥ 8 years of age and consent to study participation. Data and blood samples were collected at baseline (T0), and 12-18 weeks later (T1). Ticks collected at T0 were pooled and analyzed by real-time PCR. Serological and molecular tests were used for TBD diagnosis.

RESULTS

Ninety-three individuals (median age 39 years; 52.7% female) were enrolled. The pathogens most frequently detected in the tick pools were Rickettsia spp. (15.1%) and Borrelia spp. (7.5%). Sixteen participants (17.2%) developed TBD-compatible symptoms, but TBD was confirmed in only four cases: Lyme borreliosis (n = 2), scalp eschar and neck lymphadenopathy after tick bite (SENLAT, n = 1), and tick-borne encephalitis (TBE, n = 1). Concordance between TBP detection and the corresponding TBD development in humans was observed in only two cases (2.1%).

CONCLUSIONS

The low concordance between pathogens detected in participant-level tick pools and confirmed human tick-borne disease supports the limited clinical value of tick testing in this setting.