Investigating the survival ability of Ixodes ricinus ticks

Tick on impregnated fabric
Fig. 1: Nymph of I. ricinus on impregnated fabric.

Over the past several years we have investigated various aspects of tick biology that may be of public interest. Ticks are commonly brought into home, for example on clothes after a walk in the woods. Dogs or cats can also bring ticks into the home. The question then arises whether such ticks can survive or even reproduce, and thus pose a potential danger for humans or animals even at home.

We investigated the survival of ticks at different relative humidities commonly observed in apartments. Depending on their developmental stage, I. ricinus can survive several days or even weeks under normal room conditions. We thus advise that clothes which may be harboring ticks not be left in rooms with easy access to humans, such as bedrooms.

Can the risk of tick bites be eliminating by immediately washing clothes that have potentially been exposed to ticks? Our tests show that ticks can survive a regular washing cycle (including detergent and a spinning program) if the temperature of the water does not exceed 40 °C. However, at 60 °C or above all ticks were killed, which was also true if clothes were dried in a drier.

We also investigated the survival period of ticks when kept under water, as well as several possible methods for safely killing ticks at home. Further information can be found at www.zecken.de (in German).

ticks in a washing machine
Fig. 2: Testing of survivability of ticks in a washing machine.

ticks under water
Fig. 3: Determination of survival period of ticks under water.