Repellency testing by modified moving-object bioassay: animalprotection against ticks

The aim of this study was to evaluate use of the modified moving-object bioassay for the repellency testing in different living systems (humans, animals). It focused on behavioural observations of Ixodes ricinus (males, females, nymphs), the most common tick species in the Czech Republic and vector of numerous pathogens. During our experiment, the warmth, surface and olfactory properties were modified by using a filter paper (representing a smooth skin of a potential human host) or goat and rabbit fur as the contact surface area for ticks. The used repellent contained N, N-diethyl-m-toluamide (140 g/kg) and deltamethrin (0.1 g/kg) as the active substances, the dosage reflected the manufacturer's instructions. Without any repellent treatment, the surface was found to be attractive for 54% (filter paper), 89% (goat fur) and 95% (rabbit fur) of nymphs. When the repellent was applied, number of nymphs, which contacted the surface, significantly decreased.