ABSTRACT
Abstract Londrina is the fourth most populous city in southern Brazil. Its subtropical weather with rain in all seasons, as well as its high population density, make the city perfect for the Aedes aegypti (Linnaeus, 1762) life cycle. Over the last few years, Londrina presented high infestation indexes and was one of the cities with the most reported cases of dengue. Uncontrolled use of synthetic insecticides may influence the mosquito's genetic composition. In this paper, we studied mitochondrial DNA and kdr mutations in Aedes aegypti. The analysis of the ND4 gene in 330 specimens showed the presence of 27 haplotypes. The pyrethroid resistance alleles (kdr) evaluated are present in the collected populations, with a 50% frequency of the Val1016Ile and 48% of the Phe1534Cys mutations. Such analysis of the mutations in the populations collected at the State University of Londrina's campus - a microenvironment that differs from the rest of the city - showed frequencies of 57% and 62%, respectively. The low gene flow observed, Nm = 0.11 and Nm = 0.10, along with the elevated differentiation, Fst = 0.19 and Fst = 0.18, among populations suggest an influence of genetic drift. The strong presence of resistance alleles kdr in the city is evident, which demonstrates that even with the interruption of the use of pyrethroids by the National Dengue Control Program, resistance may be maintained due to domestic use. Thus, the results have shown the need for genetic monitoring, alongside other entomological surveillance monitoring tools, to create strategies of mosquito control.
ABSTRACT
ABSTRACT The aim of this study was to analyze the effectiveness of different control agents of Aedes aegypti and Aedes albopictus associated with ovitraps under laboratory and field conditions. Five treatments were used: grass infusion + Bacillus thuringiensis israelensis (gI + Bti), grass infusion + Saccharopolyspora spinosa (gI + Ss), grass infusion + Pyriproxyfen (gI + P), distilled water + Toxorhynchites haemorrhoidalis (dW + Th), and grass infusion (gI) (control). The highest mean number of eggs of both species were obtained with grass infusion in the laboratory. Among control agents, the lowest mean of A. aegypti eggs occurred with gI + Ss and the lowest mean of A. albopictus eggs occurred with dW + Th. There was no difference between treatments in A. aegypti (P = 0.4320) and A. albopictus (P = 0.7179). In the field, the highest mean number of eggs for both species were obtained with gI + Ss, and the lowest values were obtained with gI + P (P = 0.0124). The treatments can be applied to both the surveillance and the control, but ovitraps with biological larvicide Bti were more effective and safer considering the number of eggs laid and selectivity of pathogens for mosquitoes.
ABSTRACT
Aedes aegypti (Linnaeus, 1762) é o principal vetor do vírus do dengue, e coloca sob risco metade da população mundial. É um mosquito antropofílico e veicula também os vírus Chikungunya e Zika vírus. Aedes albopictus (Skuse, 1894) é abundante em áreas com vegetação próximas a residências e pode transmitir os vírus Chikungunya e febre amarela. Estratégias de monitoramento e controle desses vetores são necessários para redução da circulação viral. Estimar a variação populacional de Ae. aegypti e Ae. albopictus em relação à urbanização e aferir relações de sobreposição e competição desses vetores com o uso de ovitrampas foram os objetivos deste estudo. A amostragem foi realizada em 10 locais no campus da Universidade Estadual de Londrina, entre abril e outubro de 2015. A ovitrampa foi elaborada com pote plástico escuro, contendo no seu interior água, uma palheta, mistura atrativa e temephós. Os ovos coletados nas palhetas foram submetidos a eclosão para identificação das espécies por meio das larvas. Coletou-se 46.879 ovos de Aedes e abril apresentou a maior densidade de ovos (IDO=49,0). A temperatura apresentou forte correlação (r=0,88) com a atividade de oviposição, entre abril a julho. Aedes aegypti predominou em áreas urbanas nos diferentes locais. Os resultados obtidos comprovam que a ovitrampa é uma ferramenta eficaz para monitorar e auxiliar em estratégias de controle da população destes vetores.
Aedes aegypti (Linnaeus, 1762) is the main vector virus of dengue, and puts at risk half of the world population. It is an anthropophilic mosquito and carries the Chikungunya and Zika viruses. Aedes albopictus (Skuse, 1894) is abundant in vegetated areas near residences and can transmit Chikungunya virus and yellow fever. Strategies for monitoring and controlling these vectors are necessary to reduce viral circulation. Estimate the population variation of Ae. aegypti and Ae. albopictus in relation to urbanization and to verify relations of overlap and competition of these vectors with the use of ovitraps were the objective of this work. The research was carried out in 10 sites in the campus of the State University of Londrina, from April to October of 2015. The ovitrap was elaborated with dark plastic pot, containing in its interior water, a palette, attractive mixture and temephós. The eggs collected on the palettes were stimulated to hatch to identify the species through the larvae. We collected 46,879 Aedes eggs and April had the highest egg density (IDO=49.0). The temperature had a strong correlation with to oviposition activity between April and July (r=0.88). Aedes aegypti predominated in different sites in the urban areas. The results obtained prove that ovitrap is an effective tool to monitor and assist strategies to control the population of these vectors.