Dados do Trabalho

Título

Aedes aegypti strain subjected to a chronic exposure to Bacillus thuringiensis svar. israelensis-based larvicide displays altered susceptibility to Zika virus

Introdução

Bacillus thuringiensis svar. israelensis (Bti)-based larvicides have beeb used to control Aedes aegypti. Its effectiveness and lack of mosquito resistance to Bti have been well documented, however, little is known about the impact of the chronic use of these larvicides on the life traits of mosquitoes. This is an important aspect since, in endemic countries, larvicides are applied throughout the year and to control Aedes populations.

Objetivo (s)

This study aimed at comparing biological parameters, including larvae susceptibility to Bti, female ssuctibility to Zika (ZIKV) and dengue (DENV) virus, of an Ae. aegypti strain (RecBti) exposed to Bti for 29 generations under laboratory condition, and a reference strain (Ref).

Material e Métodos

For that, biological parameters of individuals reared under controlled conditions of RecBti and Ref strains were compared.

Resultados e Conclusão

RecBti individuals, compared to RecL, were susceptible to Bti and did not display alterations in fecundity, fertility, pupal weight, developmental time, emergence rate, sex ratio and haematophagic capacity. Females from both strains were susceptible to dengue serotype 2 (DENV-2) and Zika virus (ZIKV). RecBti females showed significantly higher rates of ZIKV infection compared with RecL females at 7 (90% versus 68%) and 14 dpi (100% versus 87%) and for dissemination at 7 dpi (83.3% versus 36%). The susceptibility of RecBti females to DENV was lower, but not statistically different. Quantification of DENV-2 and ZIKV viral particles was similar results for females from both strains. Another parallel investigation showed that those females which had higher susceptibility to arbovirus displayed an altered expression of some immune genes, which supported their status. This finding was related to a background of Bti exposure for several generations and highlights that the effects of chronic exposure to Bti should be investigated.

Palavras-chave

Bti, mosquito control, ZIKV, DENV, arboviruses, vector competence

Agradecimentos

Brazilian Council of Research-CNPq (grants 4007471/2019-7) and Fundação para o Amparo à Ciência e Tecnologia do Estado de Pernambuco (FACEPE APQ-0096-2.13/16, BFP-0070-2.13/18, BFP-0090-2.13/20)