Eurosurveillance - Volume 31, Issue 20, 21 May 2026

Tick-borne encephalitis virus (TBEV) was detected in the Netherlands in 2015. Current monitoring through serology in deer, tick collection and reported human cases, may underestimate areas of virus circulation. Including estimates of suitability of the habitat for TBEV can guide risk-based monitoring.

We aimed to improve the accuracy of the TBEV distribution map by adding estimates of TBEV habitat suitability to guide targeted tick monitoring in newly identified risk regions.

Habitat suitability for TBEV was assessed by calculating the basic reproduction number (R0) for 1 km² grid cells aggregating various data sources for tick hosts such as mice or voles, tick abundance and TBEV transmission. The importance of different tick hosts was determined in scenario analyses. The baseline scenario was validated against data on seropositive roe deer and TBEV-positive ticks and rodents.

The suitability (R0 ≥ 1) was associated with tick habitat suitability and the abundance of competent host species. Variation in competent host densities had a greater effect on R0 estimates than incompetent hosts. Monitoring data corresponded well with model-predicted high-risk areas and confirmed further spread of TBEV.

The TBEV suitability map is a useful tool for targeted sentinel surveillance by identifying new risk areas, informing local municipal health services of endemic areas for potential human exposure. Our results support targeted efforts for awareness, preparedness and outbreak response, even in regions where TBEV has not yet been detected. Integrating One Health monitoring with spatial modelling can strengthen preparedness in emerging TBEV regions.

Enterovirus D68 (EV-D68) is a re-emerging pathogen that can cause acute respiratory illness in children and difficult to predict outbreaks.

To anticipate outbreaks in children, we investigated if wastewater surveillance could timely detect circulation of EV-D68 and its respective subclades in Niigata City, Japan.

During January−December 2024, wastewater samples were collected once a week for EV-D68 RNA concentration determination. Numbers of children (≤ 15 years old) admitted with wheezing to six hospitals with paediatric beds in Niigata City were monitored; in a subset of children, nasopharyngeal swabs were tested for EV-D68 during September−December. Nucleotide sequences of EV-D68 derived from patient and wastewater samples were phylogenetically analysed.

During January−December 2024, EV-D68 RNA was found in 39 (41.9%) of 93 wastewater samples. The first EV-D68 detection occurred in week 27, with RNA concentrations rising in subsequent samples. From week 32, numbers of children hospitalised with wheezing increased, peaking in week 37. Up to week 52, 195 children with wheezing were admitted to the six hospitals. The wastewater EV-D68 RNA concentrations positively correlated with paediatric hospitalisations for wheezing (ρ = 0.54, p < 0.001). In weeks 37–52, 16 (10 girls/6 boys; median age: 4.8 years; interquartile range: 3.1–7.5) of 31 hospitalised children tested for EV-D68 were positive. Strains affecting them were of subclade B3 only, while strains in wastewater belonged to subclades D1 and B3.

Wastewater surveillance timely detected an increase in EV-D68 activity, revealing the circulation of subclades undetected among patients. It thus can potentially support EV-D68 outbreak prediction and response and could possibly be extended to other pathogens.