RESUMO
Aedes aegypti, vector of dengue, chikungunya and Zika viruses, is found at high densities intropical urban areas. The dissemination of this vector is partially the consequence of failures in current vector control methods, still mainly relying upon insecticides. In the State of São Paulo (SP), Brazil, public health managers employed pyrethroids against Ae. aegypti adults from 1989 to 2000, when a robust insecticide resistance monitoring system detected resistance to pyrethroids in several Ae. aegypti populations. However, pyrethroids are also the preferred compounds engaged in household applications due to their rapid knockdown effect, lower toxicity to mammals and less irritating smell...
Assuntos
Animais , Aedes/crescimento & desenvolvimento , Piretrinas , Piretrinas/administração & dosagemRESUMO
Desde 1985, com a reinfestação do estado de São Paulo por Aedes aegypti, os estudos enfocaram fatores que propiciaram o estabelecimento da espécie, a dispersão passiva e a influência das condições climáticas na expansão geográfica desse vetor. A necessidade de monitorar a presença do inseto nas áreas infestadas foi atendida com metodologia simples, rápida, econômica e de fácil operacionalização, que permitiu avaliar os níveis de infestação, sazonalidade e flutuações das populações do vetor e determinar o impacto das medidas de controle...
Assuntos
Humanos , Animais , Aedes/crescimento & desenvolvimento , Controle de Vetores de Doenças , Dengue/prevenção & controleRESUMO
O Laboratório de Entomologia Aplicada (LEnA), instituído em 1988, está instalado em prédio próprio na cidade de Marília, com estrutura física adequada para alocação das equipes de campo, administração, insetário e laboratórios, construídos de acordo com as normas de biossegurança. Desenvolve as seguintes atividades: identificação taxonômica de artrópodes de importância médica; manutenção de colônias de Aedes aegypti; realização de bioensaios para caracterização de resistência de Aedes aegypti a inseticidas e de testes imunoenzimáticos para caracterização da atividade de enzimas envolvidas no metabolismo de inseticidas...
Assuntos
Humanos , Entomologia/métodos , Entomologia/tendências , Laboratórios/tendências , LaboratóriosRESUMO
The scarcity of information on the immature stages of sand flies and their preferred breeding sites has resulted in the focus of vectorial control on the adult stage using residual insecticide house-spraying. This strategy, along with the treatment of human cases and the euthanasia of infected dogs, has proven inefficient and visceral leishmaniasis continues to expand in Brazil. Identifying the breeding sites of sand flies is essential to the understanding of the vectors population dynamic and could be used to develop novel control strategies. Methodology/Principal finding: In the present study, an intensive search for the breeding sites of Lutzomyia longipalpis was conducted in urban and peri-urban areas of two municipalities, Promissão and Dracena, which are endemic for visceral leishmaniasis in São Paulo State, Brazil. During an exploratory period, a total of 962 soil emergence traps were used to investigate possible peridomiciliary breeding site micro habitats such as: leaf litter under tree, chicken sheds, other animal sheds and uncovered debris. A total of 160 sand flies were collected and 148 (92.5%) were L. longipalpis...
Assuntos
Animais , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/prevenção & controle , Leishmaniose Visceral/transmissão , Psychodidae/crescimento & desenvolvimentoRESUMO
The dengue virus is a vector-borne disease transmitted by mosquito Aedes aegypti and the incidence is strongly influenced by temperature and humidity which vary seasonally. To assess the effects of temperature on dengue transmission, mathematical models are developed based on the population dynamics theory. However, depending on the hypotheses of the modelling, different outcomes regarding to the risk of epidemics are obtained. We address this question comparing two simple models supplied with models parameters estimated from temperature-controlled experiments, especially the entomological parameters regarded to the mosquitos life cycle in different temperatures...
Assuntos
Humanos , Animais , Aedes/crescimento & desenvolvimento , Dengue/diagnóstico , Dengue/epidemiologia , Dengue/transmissãoRESUMO
Dengue is a vector-borne disease transmitted by the mosquito Aedes aegypti. The incidence of dengue disease shows a clear dependence on seasonal variation. How does the temperature affect the incidence? We addressed this question indirectly by estimating the size of the A. aegypti population for different temperatures applying population dynamics theory. In order to achieve this objective we designed temperature-controlled experiments to assess the entomological parameters regarding the mosquito's life-cycle at different temperatures. By obtaining the mortality, transition and oviposition rates for different stages of the life-cycle of the mosquito we were able to calculate the basic offspring number Q0, which is the capacity of vector reproduction and ultimately gives the size of the vector population...
Assuntos
Animais , Aedes , Aedes/crescimento & desenvolvimento , Aedes/químicaRESUMO
The incidence of dengue infection, a vector-borne disease transmitted by the mosquito Aedes aegypti, shows clear dependence on seasonal variation. Based on the quantification method that furnishes the size of the A. aegypti population in terms of the estimated entomological parameters for different temperatures, we assessed the risk of dengue outbreaks. The persistence and severity of epidemics can be assessed by the basic reproduction number R0, which varies with temperature. The expression for R0 obtained from true and pseudo mass action laws for dengue infection is discussed...
Assuntos
Animais , Aedes , Aedes/crescimento & desenvolvimento , Aedes/metabolismo , Aedes/químicaRESUMO
The dengue control programme in Brazil involves house-to-house inspection in each municipality, on abimonthly basis, for vector control and education activities. The sustainability of this strategy has been questioned due to its failure in interrupting dengue transmission and also by the exhaustion of field workers and lack of active cooperation by populations due to the tedious routine of bimonthly visits toall houses. An evaluation of the infestation of Aedes aegypti by larval, pupal and adult collection, and classification of houses with the premise condition index (PCI) in conjunction with residents housing characteristics was performed in 11 575 houses in Marilia, Sao Paulo state, Brazil. The results showed that the surveillance tool and associated data on resident housing characteristics were useful in identifying heavily infested premises. The index could thus provide a basis for prioritizing control measures within communities during routine vector control activities.
Assuntos
Aedes , Brasil , Controle de Vetores de DoençasRESUMO
Vector control with larvicides is an important component in dengue control programmes. In Brazil, the extensive use of temephos has led to the evolution of resistance in Aedes aegypti populations in manyparts of the country. One of the strategies proposed for managing temephos resistance is the use of theinsect-growth regulator pyriproxyfen. This study evaluated the lethal concentration for this product in mosquito populations with different profiles of susceptibility to temephos and semi-field residual responseto a commercial product. The results suggest the possibility of cross-resistance between temephos and pyriproxyfen.