Ferrari et al.
A new hotspot of tick-borne encephalitis virus (TBEV) in the Autonomous Province of Trento, Italy. Ticks Tick Borne Dis. Published online July 18, 2025. doi:10.1016/j.ttbdis.2025.102513
In Italy, the tick-borne encephalitis (TBE) virus is primarily found in the north-eastern regions. In the Autonomous Province of Trento, the number of TBE cases has increased in recent years. However, the municipality of Canal San Bovo (Upper Vanoi Valley, Trentino) had never reported any cases until 2022, when an unexpected cluster of seven infections was identified. Additional cases were subsequently observed in the same area and neighboring municipalities.
To investigate this emergence, a study was conducted to estimate tick infection prevalence in Canal San Bovo and to characterize the genetic features of local TBE virus strains. Among 458 ticks collected by dragging, the minimum infection rate was 4.6% in adults and 1.1% in nymphs, revealing a previously undetected TBE hotspot.
Genetic analyses showed that TBE virus isolates from Canal San Bovo belonged to the European subtype and clustered together in a distinct clade, encompassing isolates from both western and eastern Trentino.
The combination of a high infection prevalence in ticks and the occurrence of human cases indicates sustained TBE virus circulation in this newly identified hotspot within the Trentino Province.