Why Ixodes ricinus is increasing its geographical range

In the last two decades, several countries have reported an increasing abundance and distribution range of Ixodes ricinus, spreading into higher latitudes and altitudes (6, 19, 42–45).

The expansion of Ixodes ricinus is not completely understood but could be due to changes in host animal abundance and distribution (for example in Scotland, the increase in deer abundance and distribution (46, 47), changes in landscape structure and land use (48, 49), and environmental changes, due to climate change (6, 8).