Efeitos toxicológicos e ineficiência in vitro de deltametrina sobre larvas de Rhipicephalus sanguineus, de Goiânia, Goiás, Brasil

Abstract

It has been observed that formulations of deltamethrin developed for disinsectization of infested places and control of parasitic arthropods of bovines and equines have frequently been used by breeders of dogs to control ticks in their animals and kennels, but without due consideration of the correct dosage or means of application. With the purpose of evaluating the efficacy of this product on Rhipicephalus sanguineus, bioassays were realized with larvae at 27+/-1 degrees C, UR>80% and light period of 12 hours. The mortality and toxicological effects were observed for 30 h, at 6 h intervals. Important toxicological effects were observed on the larvae, such as lack of co-ordination, knock-down and paralysis followed by death, although the lethal capacity of the product after 30 h was low, with mean mortality of only 34%, 40.2%, 46% and 57.6% respectively, for the 0.5 ml/l; 1 ml/l; 2 ml/l/; and 3 ml/l dosages. There was no mortality in the control group. The results obtained did not indicate the use of this formulation, in the tested dosages, as a method of choice for R. sanguineus control.

Monitoring of evolution of resistance to commercial acaricidal products in Rhipicephalus sanguineus sensu lato (Latreille, 1806) (Acari: Ixodidae) from Goiânia, Goiás State, Brazil

“…Low acaricide efficiency or ineffectiveness was observed for all products composed only of pyrethroids, evaluated in this work, on larvae of R. sanguineus from Goiânia. These data are consistent with those of Fernandes and et al, 6,22,23,25 who had previously reported the loss of larvicidal efficiency of pyrethroid-based products, also in populations of R. sanguineus from this municipality, now confirmed with the results of the present Work. This becomes an obstacle for the choice of less toxic acaricides for dogs and for humans (dog breeders), to control this tick, since pyrethroids are considered, among other toxicological groups, the less toxic to mammals and therefore safer to use.…”

“…The growing number of scientific reports of ineffectiveness of commercial chemical acaricides as a result of the development of tick resistance to various acaricide bases, such as pyrethroids, formamidines, organochlorines and organophosphates, has been a reality in Brazil, Latin America and several other countries. 33,34,44,45 Fernandes and et al, 6,22,23,25 had already reported resistance of R. sanguineus to the synthetic pyrethroids Deltamethrin and Cypermethrin, also in Goiânia, Goiás -a picture consistent with the results found in the present study, which also revealed resistance of R. sanguineus larvae to these pyrethroids, and, now, also to Permethrin. These data confirm the increasing loss of effectiveness of pyrethroid acaricides, in the dosages recommended by the manufacturing laboratories for the control of R. sanguineus.…”

“…In Brazil, the first works on the chemical control of this species only appeared from the mid-1990s, as well as the first report of the development of acaricide-resistant populations of R. sanguineus s. l. (tropical lineage) in Brazil, carried out by Fernandes FF and his team of student researchers. 6,[22][23][24][25] More recently, the development of tolerance or resistance to different acaricide bases in different populations of Rhipicephalus sanguineus has been reported in other locations around the world. 4,[26][27][28][29] The accomplishment of regional studies to monitoring the susceptibility or resistance of R. sanguineus to chemical acaricides is of fundamental importance to guide local communities in choosing more efficient acaricide products, with a view to the health of domestic dogs, the reduction of the environmental impact with the rational use of these toxic products, and the decrease in the occurrence of cases of emerging tick-borne diseases in humans.…”

Controle de Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) no canil da Escola de Veterinária da UFMG, Belo Horizonte, Minas Gerais, Brasil

“…Assim, por se desenvolver em ambientes sinantrópicos de várias cidades do país, onde ocorre em alta densidade e prevalência, este carrapato poderá vir a causar aumento na incidência de Erliquiose, Babesiose e Febre Maculosa, como antropozoonoses emergentes (FERNANDES et al, 2001).…”

Native strains of Beauveria bassiana for the control of Rhipicephalus sanguineus sensu lato

“…Due to their ability to survive under different climatic conditions and ecological niches, these ticks have a cosmopolitan distribution and their control is still a major challenge for veterinarians and pet owners. The main line of defence against ticks is the use of chemicals [ 2 ], although this approach may present disadvantages such as the development of resistance, human and animal toxicity and environmental pollution [ 3 , 4 ]. For example, the resistance of R. sanguineus s.l.…”