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Speakers - Lígia Miranda Ferreira Borges

Type of the Presentation: (Short lecture)

 

IDENTIFICATION AND QUANTIFICATION OF NON-HOST SEMIOCHEMICALS FOR THE BRAZILIAN SPOTTED FEVER VECTOR, AMBLYOMMA SCULPTUM (ACARI: IXODIDAE), FROM TICK-RESISTANT HOSTS, EQUUS ASINUS

 

Lorena Lopes Ferreira, Andre Lucio Franceschini Sarria, Jaires Gomes de Oliveira Filho, Fernanda de Oliveira Silva, Stephen J. Powers, John C. Caulfield, John A. Pickett, Michael A. Birkett, Lígia Miranda Ferreira Borges

 

1  Universidade Federal de Goiás, Instituto de Patologia Tropical e Saúde Publica

*  Correspondence: ligia@ufg.br

 

Amblyomma sculptum parasites a variety of hosts and has medical and veterinary importance. Once olfactory cues are involved in tick-host interactions, repellents, produced by resistant hosts, are been proved as an alternative to control ticks. In natural and artificial interrelation between donkeys (Equus asinus), horses (Equus caballus) and A. scultptum, it was shown that donkeys are more resistant than horses. Considering that tick-resistant dogs produce repellents against Rhipicephalus sanguineus sensu lato ticks, here we investigated whether donkeys produce compounds that can act as repellent to A. sculptum. Sebum of ten donkeys and ten horses were collected. The odors were extracted from the dry sebum extract and the compounds there of identified by gas chromatography (GC) and coupled GC-mass spectrometry. Six main compounds were identified been five occurring in both species and one exclusively present on donkeys. Bioassays with A. sculptum nymphs in a Y-tube olfactometer were done using the odors, and the six compounds identified from the two species at 1.0M, 0.5M, 0.25M and 0.125M. The dry sebum extract and the compounds identified in both species did not show any effect. Only donkey compound was repellent and maintained a statistically significant repellence rate at four concentrations tested (p<0.05 Chi-squared test).  The effect of a combination of the donkey compound (0.25M) and a tick attractant (ammonium hydroxide 0.25M) was also investigated and it was observed repellency (p<0.05, Chi-squared test). The mean of the quantification of donkey compound in three donkey sebum extracts was 2.602 µg mL-1. These results indicate that the semiochemical identified here could be used to interfere in tick behavior and is therefore a potential compound to be transformed in a new technology to control A. sculptum.