ORIGINAL PAPER Photosensitizers in the fight against ticks: safranin as a novel photodynamic fluorescent acaricide to control the camel tick Hyalomma dromedarii (Ixodidae) Hanem Khater 1 & Nabil Hendawy 2 & Marimuthu Govindarajan 3 & Kadarkarai Murugan 4 & Giovanni Benelli 5,6 Received: 12 May 2016 /Accepted: 13 May 2016 # Springer-Verlag Berlin Heidelberg 2016 Abstract Ticks transmit more pathogen species than any oth- er group of blood-feeding arthropods worldwide, affecting humans, livestock, and companion animals. Hyalomma dromedarii is the predominant tick species infesting camels, and its effective control is of pivotal importance. In this re- search, we compared the phytoefficacy of safranin (SF), a fluorescent dye applied as an acaricide for the first time, to that of tetramethrin (TM) against engorged females of H. dromedarii through in vitro immersion bioassays. Furthermore, the effect of SF exposure was evaluated on the reproductive potential of surviving tick females. Different concentrations of SF (0.03, 0.06, 0.3, 1, and 4 % w:v) and TM (0.03, 0.13, 0.5, 2, and 4 %) were prepared in distilled water and administered to engorged females of H. dromedarii. SF-treated ticks were illuminated with a light source for 30 min post-treatment (PT). Photophysical properties of SF were studied, and the relative efficacy of the used light source and sunlight was calculated. Results showed that the mini- mum least concentration that causes 100 % acaricidal effect was 4 % PTwith SF and TM, for 8 and 48 h, respectively. LC 50 values 8 and 24 h PT were 0.08, 0.03 and 0.78, 0.20 %, respectively. Comparing LC 50 and LC 90 2 h PT, SF was 33 and 22 times more potent than TM. LT 50 of 4 % SF and TM were 0.80 and 2.17 h, respectively. Treatment with the lowest concentrations of SF and TM induced reduction of the number of ovipositing females, eggs per female, ticks laying viable eggs, and hatched eggs. Overall, our results highlighted that SF is highly effective if compared to TM, allowing use to candidate it for the development of novel and safer acaricides. Keywords Africa . Arbovirus . Fluorescent material . Ixodidae . Ovicides . Reproductive potential . Tetramethrin . Tick-borne diseases Introduction Arthropods are dangerous vectors of deadly diseases, which may hit as epidemics or pandemics in the increasing world population of humans and animals (Benelli 2015; Benelli and Mehlhorn 2016; Benelli et al. 2016a, b). Among them, ticks transmit more pathogen species than any other group of blood-feeding arthropods worldwide, affecting humans, live- stock, and companion animals (Mukhebi et al. 1999; Sonenshine et al. 2002; Bissinger and Roe 2010; Dantas- Torres et al. 2012; Pfäffle et al. 2013). Currently, almost 900 tick species have been described. In European countries, sev- eral tick species, such as Ixodes ricinus and Ixodes persulcatus, attack humans and numerous animal species (Mehlhorn et al. 2012; Sonenshine and Roe 2014; Abdel- Ghaffar et al. 2015). They are important vectors of agents of * Giovanni Benelli g.benelli@sssup.it; benelli.giovanni@gmail.com 1 Department of Parasitology, Faculty of Veterinary Medicine, Benha University, Moshtohor, Toukh 13736, Egypt 2 Department of Physics, Faculty of Science, Benha University, Benha 13111, Egypt 3 Unit of Vector Control, Phytochemistry and Nanotechnology, Department of Zoology, Annamalai University, Annamalainagar, Tamil Nadu 608002, India 4 Division of Entomology, Department of Zoology, School of Life Sciences, Bharathiar University, Coimbatore, Tamil Nadu 641046, India 5 Insect Behavior Group, Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, Pisa 56124, Italy 6 The BioRobotics Institute, Sant’Anna School of Advanced Studies, Viale Rinaldo Piaggio 34, Pontedera 56025, Italy Parasitol Res DOI 10.1007/s00436-016-5136-9