Hyalomma marginatum (HM), native to the Mediterranean area, northern Africa and parts of Asia, is a vector of Crimean-Congo haemorrhagic fever virus and other pathogens. Recently, adult HM were frequently recorded in Central Europe. Therefore, personal protection against this tick species may become increasingly important. We investigated the repellent effect against HM of three active ingredients commonly used in repellent products against arthropod vectors. In an in vitro approach, 20% ethanolic solutions (w/w) of DEET, Icaridin, and EBAAP were tested on a temperature controlled surface for repellency against HM adults. Ticks were individually placed on the untreated centre of the surface and observed for a maximum of 3 min. Ticks walking more than 10cm in any direction were regarded as not repelled. Ticks remaining in the untreated centre or falling off the treated surface were regarded as repelled. Additionally, Icaridin was tested in vivo on the human arm. Ticks were regarded as not repelled when walking more than 10 cm on treated skin. In vitro, repellent efficacies against HM of the three active ingredients tested were below 20% with Icaridin achieving the highest repellency. Applied on human skin, 20% Icaridin repelled most of the ticks within a walking distance of 3 – 10cm. The results render Icaridin as suitable positive control for evaluation of repellents against HM using human subjects with a walking distance of at least 10cm as criterion for “not repelled”. Efficacy data of this “hunter” tick are not easily transferable to other tick species.
