Repellent activity of the non-host semiochemical (E)-2-octenal against Amblyomma sculptum and Amblyomma dubitatum ticks under field conditions.

Amblyomma ticks pose a significant public health threat due to their potential to transmit pathogens associated with rickettsial diseases. (E)-2-octenal, a compound found in donkeys (Equus asinus), exhibits strong repellent properties against Amblyomma sculptum nymphs under laboratory conditions. This study assessed the effectiveness of the (E)-2-octenal in wearable slow-release devices for personal human protection against Amblyomma ticks under natural conditions.

Repellent and acaricidal activity of coconut oil fatty acids and their derivative compounds and catnip oil against Amblyomma sculptum.

This study was carried out aiming to evaluate the repellent and acaricidal activity of major ingredient compounds from coconut oil including their methyl ester derivatives and catnip oil against nymphs and larvae of Amblyomma sculptum. Repellent candidates, coconut oil free fatty acids (coconut FFA mainly C, C and C acid); lauric acid (C acid); capric acid (C acid); methyl laurate; methyl caprate and 10 % each of C, C and C acid (1:1:1) in lavender oil formulation (CFA in lavender formula) and catnip oil (Nepeta cataria), were screened using a Petri dish bioassay to assess repellency. Catnip oil, methyl caprate, methyl laurate, and CFA in lavender formulation repelled ticks strongly (P < 0.

Efficacy of collars with allomones on dogs to control Rhipicephalus sanguineus sensu lato infestations under field conditions.

Benzaldehyde and 2-hexanone are allomones produced by beagle dogs that reduce infestation by Rhipicephalus sanguineus sensu lato on these animals and on susceptible dogs which artificially release these repellents. These observations were obtained in previous laboratory tests or artificial infestations of susceptible dogs under controlled conditions. Here we evaluated the efficacy of collars delivering these repellents for suppressing the loads of R.

Thymol and eugenol microemulsion for Rhiphicephalus sanguineus sensu lato control: Formulation development, field efficacy, and safety on dogs.

The present study aimed to develop a microemulsion formulation containing thymol and eugenol for field control of Rhipicephalus sanguineus sensu lato on dogs, as well to evaluate its safety and the physical characteristics of the formulation. The microemulsion using thymol and eugenol (5.0 + 5.

Seasonal dynamics of Amblyomma sculptum in two areas of the Cerrado biome midwestern Brazil, where human cases of rickettsiosis have been reported.

Amblyomma sculptum is a common human-biting tick in Brazil, where it plays an important role as a vector of Rickettsia rickettsii, the agent of the Brazilian spotted fever. Herein, we studied the seasonal dynamics of A. sculptum in an urban area of the Cerrado biome in midwestern Brazil, where human rickettsiosis is endemic.

First neuronal projection from Haller's organ to the synganglion and three-dimensional reconstruction of Amblyomma sculptum olfactory lobe.

Because information regarding neural and sensory functions of ticks is scarce, the aim of the present study was to ascertain the neuronal projection patterns of olfactory sensilla from Haller's organ to the olfactory lobes of the synganglion in Amblyomma sculptum adults. Additionally, the aim was to perform three-dimensional (3D) reconstruction of the glomeruli in the olfactory lobes. Unfed female and male adults of this tick species were immobilized, Haller's organ was sectioned, and the olfactory nerves were labelled with a neuronal tracer (1% dextran tetramethylrhodamine).

Identification of a non-host semiochemical from miniature pinscher, Canis lupus familiaris, that repels Rhipicephalus sanguineus sensu lato (Acari: Ixodidae).

It is already known that the beagle breed of domestic dogs produces semiochemicals capable of repelling the brown dog tick, Rhipicephalus sanguineus sensu lato (s.l.).

Combination of thymol and eugenol for the control of Rhipicephalus sanguineus sensu lato: Evaluation of synergism on immature stages and formulation development.

The aim of this study was to investigate whether the combination of thymol with eugenol has a synergistic effect on the immature life stages of Rhipicephalus sanguineus sensu lato (s.l.), to evaluate the cost-benefit ratio of using these compounds in combination, and to develop a formulation combining thymol with eugenol with activity on immature stages of R.

Identification of a non-host semiochemical from tick-resistant donkeys (Equus asinus) against Amblyomma sculptum ticks.

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.

Surface lipidome of the lone star tick, Amblyomma americanum, provides leads on semiochemicals and lipid metabolism.

Lipids extracted from the surface of the lone star tick, Amblyomma americanum, were analyzed by high resolution mass spectrometry. Prior to lipid extraction, the adult ticks were either unfed or fed on cattle, and the fed ticks were in groups either containing males and females together, or containing only males or females. Cholesteryl esters were found on the surfaces of fed females, and they may provide a more complete description of the composition of the mounting sex pheromone.

Better than DEET Repellent Compounds Derived from Coconut Oil.

Hematophagous arthropods are capable of transmitting human and animal pathogens worldwide. Vector-borne diseases account for 17% of all infectious diseases resulting in 700,000 human deaths annually. Repellents are a primary tool for reducing the impact of biting arthropods on humans and animals.

Persistence and efficacy of a new formulation based on dog allomonal repellents against Rhipicephalus sanguineus sensu lato tick.

Beagles are less susceptible to Rhipicephalus sanguineus sensu lato tick due to the production of the allomones benzaldehyde and 2-hexanone. Our previous published work showed that these compounds can reduce tick burden on susceptible dogs. Here we tested the hypothesis that an increase in repellent dose and release rate could increase repellent efficacy and persistence.

In vitro repellency of DEET and β-citronellol against the ticks Rhipicephalus sanguineus sensu lato and Amblyomma sculptum.

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 β-citronellol in a Petri dish bioassay.

Brown dog tick, Rhipicephalus sanguineus sensu lato, infestation of susceptible dog hosts is reduced by slow release of semiochemicals from a less susceptible host.

Domestic dog breeds are hosts for the brown dog tick, Rhipicephalus sanguineus sensu lato, but infestation levels vary among breeds. Beagles are less susceptible to tick infestations than English cocker spaniels due to enhanced production of 2-hexanone and benzaldehyde that act as volatile tick repellents. We report the use of prototype slow-release formulations of these compounds to reduce the burden of R.

Neuronal projections from the Haller's organ and palp sensilla to the synganglion of Amblyomma americanum§.

The present study was conducted to elucidate the neuronal pathways between peripheral olfactory and taste sensilla and the synganglion in an Ixodidae tick species. The tarsus of the front legs (olfactory nerves) and the fourth palpal segment (gustatory nerves) of unfed Amblyomma americanum males and females were excised. A neuronal tracer, dextran tetramethylrhodamine, was used for filling of the sensory neurons.

The chemosensory appendage proteome of Amblyomma americanum (Acari: Ixodidae) reveals putative odorant-binding and other chemoreception-related proteins.

Proteomic analyses were done on 2 chemosensory appendages of the lone star tick, Amblyomma americanum. Proteins in the fore tarsi, which contain the olfactory Haller's organ, and in the palps, that include gustatory sensilla, were compared with proteins in the third tarsi. Also, male and female ticks were compared.

Quantification of brown dog tick repellents, 2-hexanone and benzaldehyde, and release from tick-resistant beagles, Canis lupus familiaris.

We have recently shown that repellency of the tick Rhipicephalus sanguineus sensu lato by the tick resistant dog breed, the beagle, is mediated by volatile organic compounds (VOCs) 2-hexanone and benzaldehyde present in beagle odour. Ectoparasite location of animal hosts is affected by variation in these odour components and their ratios. The aim of this study was to quantify the release rate, and the ratio, of 2-hexanone and benzaldehyde from beagles.

In vitro activity of 3β-O-tigloylmelianol from Guarea kunthiana A. Juss (Meliaceae) on oogenesis and ecdysis of the cattle tick Rhipicephalus (Boophilus) microplus (Canestrini) (Acari: Ixodidae).

We evaluated the effects of 3β-O-tigloylmelianol from Guarea kunthiana A. Juss (Meliaceae) on oogenesis, as a larvicide and on ecdysis of the larvae and the nymphs of the cattle tick Rhipicephalus (Boophilus) microplus (Canestrini) (Acari: Ixodidae). On the oogenesis' test, 48 engorged females were divided into three groups, evaluated at 24, 48 and 72 h post-treatment.

Identification of non-host semiochemicals for the brown dog tick, Rhipicephalus sanguineus sensu lato (Acari: Ixodidae), from tick-resistant beagles, Canis lupus familiaris.

Studies have shown that the brown dog tick, Rhipicephalus sanguineus sensu lato, when fed on the beagle breed of dog, Canis lupus familiaris, development negatively affected in comparison with tick development after feeding on the English cocker spaniel breed. Thus leading to the suggestion that beagle dogs are be tick-resistant dogs. Behavioural studies have demonstrated that more ticks are attracted by extracts from cocker spaniels than from beagles and that the odour of beagles is a repellent.

Role of Rhipicephalus microplus cheliceral receptors in gustation and host differentiation.

Rhipicephalus microplus is considered the most economically important ectoparasite of cattle worldwide. It is known that zebuine breeds of cattle are less susceptible to tick infestation than taurine breeds. Contact chemoreceptors in the cheliceral pit sensilla of ticks respond selectively to phagostimulant compounds, however their role in blood feeding relative to host susceptibility to infestation remains to be fully understood.

Ovary histology and quantification of hemolymph proteins of Rhipicephalus (Boophilus) microplus treated with Melia azedarach.

This study aimed to analyze ovary histology and quantify total protein in the hemolymph of Rhipicephalus (Boophilus) microplus females treated with hexane extracts from green fruits of Melia azedarach. Eight engorged females were immersed in the extract at 0.25% concentration, and eight in water containing 5% acetone (control).

Study on cheliceral sensilla of the brown dog tick Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) involved in taste perception of phagostimulants.

Phagostimulants are chemical compounds that stimulate feeding. Some tick species are known to have pores in their inner cheliceral digits, called pit sensillum (ps), which are involved in taste perception. This study investigated the existence of ps in chelicerae of Rhipicephalus sanguineus ticks by scanning electron microscopy (SEM) and their involvement in the perception of phagostimulatory substances, such as the salts potassium chloride and sodium chloride (KCl and NaCl), sugars (glucose, sucrose and fructose), purines (guanine and hypoxanthine), the nucleotide adenosine triphosphate (ATP) and the tripeptide reduced glutathione (GSH), as well as their combinations at different concentrations.

In vitro activities of plant extracts from the Brazilian Cerrado and Pantanal against Rhipicephalus (Boophilus) microplus (Acari: Ixodidae).

A total of 73 ethanol extracts from different anatomical parts of 44 plant species belonging to 24 families, native to the Mid-Western region of Brazil, were assessed in vitro for their effect on the reproductive cycle of engorged females of the cattle tick Rhipicephalus (Boophilus) microplus, using the adult immersion test. All extracts were evaluated at the concentration of 0.2 % and, among the extracts tested, the one obtained from the fruits of Guarea kunthiana (Meliaceae) proved to be highly efficacious, showing 99.

Electrophysiological responses of the olfactory receptors of the tick Amblyomma cajennense (Acari: Ixodidae) to host-related and tick pheromone-related synthetic compounds.

In the present study, host-related and tick pheromone-related chemical compounds were tested by means of the tip-recording technique in order to obtain electrophysiological responses in olfactory sensilla of non-fed Amblyomma cajennense ticks. The following chemicals were tested on the multiporose sensilla DI.1, located anterior to Haller's organ, and the sensillum DII.