Location: Livestock Arthropod Pests ResearchTitle: In vitro repellency of DEET against the ticks Rhipicephalus sanguineus sensu lato and Amblyomma sculptum
|FERREIRA, LORENA - Federal University Of Goias|
|OLIVEIRA FILHO, JAIRES - Federal University Of Goias|
|MASCARIN, GABRIEL - Embrapa|
|Perez De Leon, Adalberto - Beto|
|BORGES, LIGIA - Federal University Of Goias|
Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/12/2017
Publication Date: 4/12/2017
Citation: Ferreira, L.L., Oliveira Filho, J.G., Mascarin, G.M., Perez De Leon, A.A., Borges, L. 2017. In vitro repellency of DEET against the ticks Rhipicephalus sanguineus sensu lato and Amblyomma sculptum. Veterinary Parasitology. 239:42-45.
Interpretive Summary: The ticks scientifically known as Rhipicephalus sanguineus and Amblyomma sculptum can bite humans and domestic animals. A common name for R. sanguineus is the brown dog tick. Some of the disease-causing agents these ticks carry can be transmitted from animals to humans. Repellents are an important tool to reduce the harm caused by blood-feeding ticks. This study aimed to compare the efficacy of the standard repellent commonly known as DEET versus the component of a plant extract called ß-citronellol. Tests conducted in the laboratory showed that A. sculptum was more sensitive to repellency by DEET and ß-citronellol than the brown dog tick. ß-citronellol had a stronger repellency effect than DEET against both ticks species. ß-citronellol could be formulated to protect humans and other animals from infestation with the brown dog tick and A. sculptum. By comparison to DEET-based products, stronger repellency with a ß-citronellol formulation could also decrease further the risk of exposure to ticks carrying disease causing agents.
Technical Abstract: Rhipicephalus sanguineus sensu lato and Amblyomma sculptum can parasite humans and domestic animals and are vectors of pathogens, including zoonoses. Repellents are an important tool of tick control. This study aimed to compare the efficacy of N,N-diethyl- 3-methylbenzamide (DEET), a standard repellent, versus ß-citronellol in a Petri dish bioassay. A semicircle of filter paper (31.8 cm2) was treated with 87 µl of one of four concentrations (0.200, 0.100, 0.050 and 0.025 mg/cm2) of ß-citronellol, DEET or solvent (ethanol). A head-to-head test was developed treating one side with increasing concentrations of ß-citronellol as above mentioned, against the highest concentration of DEET. Besides that a blank assay was performed. Three males and three females were placed in the middle of the plate and their location was evaluated 5, 10 and 30 min after the test was initiated. As a result, the time had no significant effect on repellency response of the ticks exposed to both compounds and their concentrations. The repellency response raised according with the increase of concentration. Additionally, our findings indicate that the tick A. sculptum was more sensitive to the compounds tested and ß-citronellol showed a higher efficacy than DEET. In addition, ß-citronellol could be formulated to protect humans and other animals from R. sanguineus s. l. and A. sculptum infestation, as well as the diseases transmitted by these species.