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Ticks Tick Borne Dis

Title:		Identification of a non-host semiochemical from tick-resistant donkeys (Equus asinus) against Amblyomma sculptum ticks
Author(s):		Ferreira LL; Sarria ALF; de Oliveira Filho JG; de Silva FO; Powers SJ; Caulfield JC; Pickett JA; Birkett MA; Borges LMF;
Address:		"Escola de Veterinaria e Zootecnia, Universidade Federal de Goias, Campus Samambaia, Avenida Esperanca, s/n, Campus Universitario, CEP: 74690-900, Goiania, Goias, Brazil. Electronic address: loren4_lopes@hotmail.com. Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, United Kingdom. Electronic address: andre.sarria@rothamsted.ac.uk. Escola de Veterinaria e Zootecnia, Universidade Federal de Goias, Campus Samambaia, Avenida Esperanca, s/n, Campus Universitario, CEP: 74690-900, Goiania, Goias, Brazil. Electronic address: jaires_filho@hotmail.com. Escola de Veterinaria e Zootecnia, Universidade Federal de Goias, Campus Samambaia, Avenida Esperanca, s/n, Campus Universitario, CEP: 74690-900, Goiania, Goias, Brazil. Electronic address: oliveiras.fer@outlook.com. Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, United Kingdom. Electronic address: stephen.powers@rothamsted.ac.uk. Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, United Kingdom. Electronic address: john.caulfield@rothamsted.ac.uk. Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, United Kingdom. Electronic address: pickettj4@cardiff.ac.uk. Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, United Kingdom. Electronic address: mike.birkett@rothamsted.ac.uk. Instituto de Patologia Tropical e Saude Publica, Universidade Federal de Goias, Rua 235 s/n, Setor Universitario, CEP: 74605050, Goiania, Goias, Brazil. Electronic address: borges.ligia@gmail.com"
Journal Title:		Ticks Tick Borne Dis
Year:		2019
Volume:		20190216
Issue:		3
Page Number:		621 - 627
DOI:		10.1016/j.ttbdis.2019.02.006
ISSN/ISBN:		1877-9603 (Electronic) 1877-959X (Print) 1877-959X (Linking)
Abstract:		"Amblyomma sculptum is a tick affecting animal and human health across Argentina, Bolivia, Paraguay and Brazil. Donkeys, Equus asinus, are known to be resistant to A. sculptum, suggesting that they can produce non-host tick semiochemicals (allomones), as already demonstrated for some other vertebrate host/pest interactions, whereas horses, Equus caballus, are considered as susceptible hosts. In this study, we tested the hypothesis that donkeys produce natural repellents against A. sculptum, by collecting sebum from donkeys and horses, collecting the odour from sebum extracts, and identifying donkey-specific volatile compounds by gas chromatography (GC) and coupled GC-mass spectrometry (GC-MS). From the complex collected blends, five main compounds were identified in both species. Hexanal, heptanal and (E)-2-decenal were found predominantly in donkey extracts, whilst ethyl octanoate and ethyl decanoate were found predominantly in horse extracts. One compound, (E)-2-octenal, was detected exclusively in donkey extracts. In Y-tube olfactometer bioassays 36 different A. sculptum nymphs were tested for each extract, compound and concentration. The dry sebum extracts and the compounds identified in both species induced neither attraction nor repellency. Only (E)-2-octenal, the donkey-specific compound, displayed repellency, with more nymphs preferring the arm containing the solvent control when the compound was presented in the test arm across four concentrations tested (p < 0.05, Chi-square test). A combination of a tick attractant (ammonia) and (E)-2-octenal at 0.25 M also resulted in preference for the control arm (p < 0.05, Chi-square test). The use of semiochemicals (allomones) identified from less-preferred hosts in tick management has been successful for repelling brown dog ticks, Rhipicephalus sanguineus sensu lato from dog hosts. These results indicate that (E)-2-octenal could be used similarly to interfere in tick host location and be developed for use in reducing A. sculptum numbers on animal and human hosts"
Keywords:		"Aldehydes/isolation & purification/pharmacology Alkenes/isolation & purification/pharmacology Animals Caprylates/isolation & purification/pharmacology Chromatography, Gas Decanoates/isolation & purification/pharmacology Equidae/*physiology Female Gas Chro;"
Notes:		"MedlineFerreira, Lorena Lopes Sarria, Andre Lucio Franceschini de Oliveira Filho, Jaires Gomes de Silva, Fernanda de Oliveira Powers, Stephen J Caulfield, John C Pickett, John A Birkett, Michael A Borges, Ligia Miranda Ferreira eng Biotechnology and Biological Sciences Research Council/United Kingdom Research Support, Non-U.S. Gov't Netherlands 2019/02/26 Ticks Tick Borne Dis. 2019 Apr; 10(3):621-627. doi: 10.1016/j.ttbdis.2019.02.006. Epub 2019 Feb 16"