Análise molecular e bioquímica da resistência do Boophilus microplus (acari.ixodidae) à cipermetrina

Abstract

The cattle tick (Boophilus microplus) is one of the most important ectoparasites for Brazilian agriculture and other tropical and subtropical regions, being responsible for significant economic losses. It is estimated that this parasite causes 65% direct damage and 35% indirect damage to cattle raising, leading to losses in milk production, birth, weight gain, increased mortality and tick consumption, and damage to the leather industry. . Among the various control methods, we highlight the use of pyrethroid-based ticks that exert a neurotoxic effect on the parasite's sodium channel, gradually promoting its inactivation. Some mutations in the teleogen sodium channel gene of this tick have been described, conferring insensitivity sites to the neurotoxic effect of pyrethroids. Resistance to this group of ticks may also be mediated by esterases such as acetylcholinesterase (AchE), in which high levels of resistance were evidenced by the combination of several mutations in the active site of this enzyme. Testing with esterase inhibitors indicated the presence of an esterase in this AchE group of B microplus associated with resistance to cypermethrin (pyrethroid). Preliminary data with Single strand conformation polymorphism (LIS-SSCP) showed a difference in the migration of 337 bp fragments of the sodium channel domain IIIS6 from sensitive and resistant teleogens. A new method for detection of mutations in gene products, called LSART (low stringency asymmetric RT-PCR), was performed. LSART data also suggested the presence of other mutations in the sodium channel of B. microplus2 teleogens. polymorphic bands, when resistant to cypermethrin-resistant teleogins, in a population of Uberlandia, Minas Gerais.