Ecological and environmental factors affecting the risk of tick-borne encephalitis in Europe, 2017 to 2021
During the last decades, the number of tick-borne encephalitis (TBE) cases reported in Europe has increased, making TBE a growing concern for public health. It is difficult to identify TBE risk areas, as the circulation of the TBE virus depends on the interplay between numerous environmental and ecological conditions. Our aim was to summarise all the different aspects that enhance TBE spread and identify the main forces that affect the distribution of TBE human infections in Europe.
TBE is a seasonal disease, dependent on tick abundance and activity. We found that TBE spread is favoured by the presence of key animal species, such as deer and rodents, in forested areas. We also discovered that specific climatic conditions, such as high precipitation during the driest months of the year, cold winters, small daily temperature variations and a steep decrease in late summer temperatures, increase the risk of TBE infections in humans.
The identification of all the environmental and ecological aspects that are influencing the risk of TBE across Europe is fundamental for the rapid assessment of potential TBE outbreaks. Hence, this study will be used to inform future risk mapping efforts in Europe and in the long run improve the targeting of prevention and control measures.