Scientists monitoring the country’s tick population captured over 16,500 from standard collection points all over the country last year, 64% more than the average over the past six years, the public health institute RIVM said at the weekend.

The increase was due to a surge in the number of juvenile ticks and larvae and the number of adults remained the same at about 400, the RIVM said.

In addition, the RIVM and Wageningen University received reports of 9,000 tick bites over the year.

Some 20% of the 1,500 ticks sent for analysis by members of the public last year were carrying Lyme disease, the RIVM said. Around 2% of the people who sent in a tick went on to develop the disease.

Lyme can cause problems with the joints, heart and central nervous system if left untreated.

People who spend time in areas known to have a high tick population, such as the Utrechtse Heuvelrug, the Veluwe heathland areas and the dunes west of Amsterdam, are being warned to check carefully for bites at the end of a day out.