Ticks transmit more pathogen species than any other 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 research, 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 4Â % w:v) and TM (0.03, 0.13, 0.5, 2, and 4Â %) were prepared in distilled water and administered to engorged females of H. dromedarii. SF-treated ticks were illuminated with a light source for 30Â 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 minimum least concentration that causes 100Â % acaricidal effect was 4Â % PT with SF and TM, for 8 and 48Â h, respectively. LC50 values 8 and 24Â h PT were 0.08, 0.03 and 0.78, 0.20Â %, respectively. Comparing LC50 and LC90 2Â h PT, SF was 33 and 22 times more potent than TM. LT50 of 4Â % SF and TM were 0.80 and 2.17Â 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.
Photosensitizers in the fight against ticks: safranin as a novel photodynamic fluorescent acaricide to control the camel tick Hyalomma dromedarii (Ixodidae)
BENELLI, GIOVANNI
2016-01-01
Abstract
Ticks transmit more pathogen species than any other 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 research, 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 4Â % w:v) and TM (0.03, 0.13, 0.5, 2, and 4Â %) were prepared in distilled water and administered to engorged females of H. dromedarii. SF-treated ticks were illuminated with a light source for 30Â 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 minimum least concentration that causes 100Â % acaricidal effect was 4Â % PT with SF and TM, for 8 and 48Â h, respectively. LC50 values 8 and 24Â h PT were 0.08, 0.03 and 0.78, 0.20Â %, respectively. Comparing LC50 and LC90 2Â h PT, SF was 33 and 22 times more potent than TM. LT50 of 4Â % SF and TM were 0.80 and 2.17Â 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.