Science - September 2, 2009

Record high for ticks this summer

Fewer mice may mean more ticks in vegetation. Up to a quarter of all ticks are infected with Lyme bacteria.

Ticks at various stages of development
   The summer of 2009 was great for ticks, according to research by Arnold van Vliet of the Environmental Systems Analysis Group and the Laboratory of Entomology. But Van Vliet does not have a watertight explanation for the high numbers. 'There was a drop in the number of mice caught in several areas. So it's possible that this is why there are more ticks in the vegetation', he speculates.
Ticks create problems as they are carriers of Lyme disease. 'In some years, up to a quarter of the ticks can be infected with the Lyme-causing Borrelia bacteria', says van Vliet. The unsuspecting hiker should watch his step, especially in May and June, when the spidery little devils are all over the place. 'But ticks can be present everywhere at any time,' stresses Van Vliet. An average of as many as five ticks can be found in one square metre. Although the numbers of tick attacks vary greatly in the different catchment areas, temperature rises in every season seem to be in their favour.
Van Vliet will draw up a tick-risk map of The Netherlands once he can gather enough data. 'The big variations in numbers and in the infection from the Borrelia bacteria make it difficult to discern a trend at this moment', he explains.
For the unfortunate tick-bite victim, a simple but effective bit of advice: 'Remove the tick as soon as possible with a pair of tick tweezers or pincers or even with your nails to minimize the chances of infection. /HW