Abstract
Zoonoses are major causes of morbidity and mortality worldwide. Among them, Brazilian Spotted Fever (BSF) is an important one that occurs in some regions of South America and can be transmitted by the "star tick" Amblyomma sculptum. Application of acaricides against the larval stage is important as strategy of population control. However, there is still a deficiency of studies on chemical control of A. sculptum and the present work aims to evaluate the in vitro acaricidal activity of cypermethrin, flumethrin, deltamethrin, fipronil, coumaphos and chlorpyrifos against A. sculptum larvae. Bioassays were performed using the larval immersion test method. A discriminatory analysis between the antiparasitic classes most used for tick control was carried out, which made it possible to determine the classes with higher potential for controlling A. sculptum larvae. Our results showed that A. sculptum larvae present highest sensitivity to the synthetic pyrethroid group, followed by the phenylpyrazole, organophosphate and macrocyclic lactone groups. These findings may support studies on improvement of tick control as in animals as in the environment.
Highlights
Ticks are widely distributed in Brazil with 70 species, being the Amblyomma genera (32 spp.) the most representative (Dantas-Torres et al, 2019)
The bioassay results showed that all the active ingredients tested exhibited acaricidal activity against A. sculptum larvae (Table 2)
The best efficacy results were found for the synthetic pyrethroid group, which achieved 100% efficacy at the concentrations of 0.625 μg.mL-1, 5 μg.mL-1 and 20 μg.mL-1, for flumethrin, deltamethrin and cypermethrin respectively
Summary
Ticks are widely distributed in Brazil with 70 species, being the Amblyomma genera (32 spp.) the most representative (Dantas-Torres et al, 2019). They need to feed on the blood of vertebrates (mainly mammals) and are responsible for causing cutaneous lesions, anemia, inoculation of toxins and transmission of pathogens. These occurrences can lead to host death (Prata, 2005; Rodrigues et al, 2015; Moraes-Filho, 2017). Infected ticks can transmit the bacterium Rickettsia rickettsii, etiological agent of Brazilian Spotted Fever (BSF), an important zoonosis and the most lethal rickettsiosis in the world (Bechah et al, 2008; Labruna et al, 2002; Labruna, 2009).
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Schedule a callMore From: Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology : Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria
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