Tedesco A, et al.
Tick-borne infections: Results from a prospective observational study from a single centre in northern Italy. Pathogens. 2026;15:736. doi:10.3390/pathogends15070736
When bitten by a tick, many individuals become concerned about the possibility of acquiring a tick-borne infection. Some laboratories offer testing services to analyse individual tick(s) for the presence of selected pathogens.
An Italian team conducted a prospective observational study at a hospital in Verona, northern Italy, to (i) estimate the proportion of participant-level tick pools testing positive for at least one pathogen, (ii) estimate the proportion of tick-borne diseases (TBDs) transmitted to humans following a tick bite, and (iii) identify emerging TBDs.
The ticks were analysed for tick-borne encephalitis (TBE) virus, Borrelia burgdorferi sensu lato, B. miyamotoi, B. afzelii, B. garinii, B. hermsii, Anaplasma phagocytophilum, Rickettsia spp., Ehrlichia chaffeensis, Ehrlichia muris, Babesia microti/divergens, and Coxiella burnetii.
A total of 120 individuals presented to the hospital following a tick bite, of whom 93 were enrolled in the study. In 77/93 (82.8%) cases, participants presented with one tick; in six (6.5%) cases, with two ticks; and in 10/93 (10.8%) cases, with three or more ticks. Of the 93 tick pools (143 ticks in total), 90 (96.8%) consisted of Ixodes spp. The remaining ticks comprised one Dermacentor marginatus, one Hyalomma marginatum, and one Aponomma spp. (originating from Malawi). Overall, 30 tick pools (32.2%) tested positive for at least one pathogen.
In this study, concordance between pathogens detected in tick pools and the final diagnosis of TBD was low, occurring in only 2 of 93 participants (2.1%).
The two concordant cases were:
- One patient with scalp eschar and neck lymphadenopathy, in whom Rickettsia slovaca was detected in the attached D. marginatus tick.
- One patient with erythema migrans, in whom Borrelia spp. and Rickettsia spp. were detected in the attached Ixodes ricinus tick.
This study demonstrated the limited clinical value of tick testing in this setting. The majority of suspected TBDs were not confirmed by laboratory testing. A TBD was diagnosed in 4.3% of participants, but concordance between pathogens detected in ticks and the clinical diagnosis was confirmed in only two cases (2.1%).