There has been a sharp rise in the number of tick bites reported in May and June this year, the public health institute RIVM said on Monday.

So far reports to the tick hotline Tekenrader.nl are up 13% on the average over the past three years and the RIVM expects over 400,000 people will be bitten this month. June is considered the peak in the tick season.

Half of the reports were made by people who were bitten while walking in woods and one third were bitten while in their own gardens. Over one in five reports came from Gelderland province.

The RIVM says people who have been out for a walk in woody areas should check themselves carefully for ticks on their return. Some 25,000 people a year are diagnosed with Lyme’s disease in the Netherlands, according to RIVM figures.