The number of tick bites across the Netherlands is already unusually high early in the season, with officials warning the peak has not yet arrived. The trend is based on data from tekenradar.nl, a monitoring initiative run by the RIVM and Wageningen Universiteit. A biologist who spoke to NOS expects the peak in tick bites next week or the week after, while noting that July remains uncertain. Last year, the peak occurred in June and marked the highest number of reports in five years.

The system tracks weekly reports from several hundred people who indicate whether they were bitten by a tick. Two weeks ago, 28 percent of participants reported a tick bite, a level that is typically associated with peak conditions rather than early-season activity.

Weather conditions seem to be a major factor. In mid-May, rainfall created favorable conditions for ticks, followed by extreme heat later in the month. That combination has reportedly contributed to increased tick activity.

Biologist Arnold van Vliet from Wageningen Universiteit said the sequence of weather events played a direct role in tick behavior and human risk exposure.

“The drought in spring was good for us, because in principle it makes ticks less active,” he told NOS. “But the rainfall in mid-May came at a good moment for the ticks. As a result, they dried out less, which affects how they go hunting. And with the nice weather, many people went into green spaces, meaning you enter the tick’s domain.” He added, “After a visit to green areas, do a tick check.”

Van Vliet said current conditions suggest another surge is likely soon. “It is rainy now, but temperatures seem to rise again sharply, and precipitation chances are decreasing exactly in the peak season.”

Public health guidance emphasizes rapid removal of ticks. Van Vliet noted that earlier advice focused on removal within 24 hours, but that guidance has changed, saying, “now we know: the faster you remove it, the lower the chance of contracting Lyme disease.”

Beyond Lyme disease, ticks in the Netherlands can also transmit tick-borne encephalitis (TBE), a viral infection that can cause meningitis.

The virus is more common in Central and Eastern Europe. In recent years, the Netherlands has seen an increase in TBE infections, which researchers suspect are partly linked to climate change.

Climate patterns are reshaping tick dynamics in multiple ways. Warmer winters reduce tick mortality and may extend their active period.

The Scientific Climate Council (WKR) and the Health Council of the Netherlands have recently advised the Dutch government that climate change is broadly favorable for tick expansion. Van Vliet said the evolving relationship between climate change and tick populations should be closely monitored in the coming years due to potentially serious public health impacts.