Avaliação preliminar da tecnologia "MI-Dengue" para o monitoramento e controle do Aedes aegypti

The "Intelligent Dengue Monitoring" technology (MI-Dengue) consists of a trap that captures gravid female Aedes aegypti, and is coupled with a computerized system for field data collection, transmission, and access to georeferenced maps in real time. This study describes the first experience with a system for monitoring adult Aedes aegypti. It presents the preliminary results in the three municipalities that adopted MI-Dengue as a strategy to identify key areas and orient control measures. Preliminary results suggest that this control strategy combined with house-to-house visits in a 200m radius of the trap helped reduce dengue in the municipalities that adopted the system.As limitações na identificação do Aedes aegypti em laboratório e no processamento das informações obtidas em campo pelo método da pesquisa larvária levaram ao desenvolvimento do "Monitoramento Inteligente da Dengue" (MI-Dengue). O MI-Dengue consiste em uma armadilha que captura fêmeas grávidas de Ae. aegypti associada ao sistema informatizado de coleta, transmissão e acesso das informações de campo, e mapas georreferenciados em tempo real. O objetivo deste trabalho foi descrever pela primeira vez um sistema de monitoramento de adultos de Ae. aegypti e apresentar os resultados preliminares em três municípios que adotaram o MI-Dengue como estratégia para identificar áreas e direcionar as ações de controle. Semanalmente, mapas georreferenciados e o indicador entomológico (IMFA) forneceram informações das áreas onde os níveis de infestações, caracterizados por cores em função da quantidade de fêmeas de Ae. aegypti capturadas, indicaram situação de sem risco, alerta e crítica que desencadearam ações de controle. Os resultados preliminares sugerem que a adoção dessa estratégia de controle com visitas casa a casa em um raio de 200m da armadilha positiva contribuiu para a redução de casos de dengue nos municípios que adotaram o MI-Dengue

DISTÂNCIA DE ATUAÇÃO EM OLFATÔMETRO DO FEROMÔNIO SEXUAL DE ATRAÇÃO DE Anocentor nitens (ACARI : IXODIDAE), 2,6-DICLOROFENOL

Neste trabalho determinou-se a distância de atuação do 2,6-diclorofenol (2,6-DCF), em um olfatômetro, visando obter subsídios para o uso de iscas deste feromônio para o controle de Anocentor nitens. Foram liberados, individualmente, vinte machos sexualmente maduros, nas distâncias de 5 e 10 cm, diante de septos de borracha limpos e tratados com 50, 500 e 5.000 ng de 2,6-DCF e fêmeas atrativas. As fêmeas, na distância de 5 cm, já não atraíram os machos, pois os percentuais de orientação e de ângulos em cada categoria foram similares. Em ambas as distâncias, os melhores desempenhos foram observados para os machos testados nas menores concentrações do 2,6-DCF, cujos percentuais de orientação foram mais altos; os machos tiveram de ser testados menos vezes; as freqüências de ângulos entre 0° e 10°, que indicam a atração do carrapato para a fonte de odor, foram maiores. Os machos foram igualmente rápidos para alcançar o septo tratado com qualquer concentração do 2,6-DCF, do que para as fêmeas ou septo controle.Esses resultados demonstram o marcado papel do 2,6-DCF como atraente para A. nitens nas concentrações de 50 a 500ng e a possibilidade do seu uso como isca, associado ou não a um acaricida, no controle desse carrapato. PALAVRAS-CHAVE: Anocentor nitens, olfatometria, feromônio sexual, 2,6-diclorofenol

Factors associated with the occurrence of dengue epidemics in Brazil: a systematic review

Objective To identify and describe broadly the factors related to the occurrence of dengue epidemics in Brazil. Methods Systematic review of studies published in Medline, Lilacs, PubMed, Cochrane, BVS, Web of Science, Scopus, and thesis and dissertations databases using descriptors cataloged in DeCs and MeSH on dengue and factors associated with the occurrence of epidemics, published from 2008 to 2018. Results Thirty-five studies carried out in the country were selected. The epidemics recorded in Brazil were associated and/or correlated with multiple factors such as environment, socioeconomic conditions, climate, and aspects related to the vector, among others. Conclusions. Dengue epidemics are complex and multifactorial. The continuity of the vector control actions was found to be relevant to the reduction of Aedes aegypti and for disease control. To contain the spread of the disease, effective measures are needed in all sectors, including health, education, economy, population, business, and government. Actions for the early detection of cases of the disease can prevent new outbreaks of epidemics

The spatial and temporal scales of local dengue virus transmission in natural settings:a retrospective analysis

Background Dengue is a vector-borne disease caused by the dengue virus (DENV). Despite the crucial role of Aedes mosquitoes in DENV transmission, pure vector indices poorly correlate with human infections. Therefore there is great need for a better understanding of the spatial and temporal scales of DENV transmission between mosquitoes and humans. Here, we have systematically monitored the circulation of DENV in individual Aedes spp. mosquitoes and human patients from Caratinga, a dengue endemic city in the state of Minas Gerais, in Southeast Brazil. From these data, we have developed a novel stochastic point process pattern algorithm to identify the spatial and temporal association between DENV infected mosquitoes and human patients. Methods The algorithm comprises of: (i) parameterization of the variogram for the incidence of each DENV serotype in mosquitoes; (ii) identification of the spatial and temporal ranges and variances of DENV incidence in mosquitoes in the proximity of humans infected with dengue; and (iii) analysis of the association between a set of environmental variables and DENV incidence in mosquitoes in the proximity of humans infected with dengue using a spatio-temporal additive, geostatistical linear model. Results DENV serotypes 1 and 3 were the most common virus serotypes detected in both mosquitoes and humans. Using the data on each virus serotype separately, our spatio-temporal analyses indicated that infected humans were located in areas with the highest DENV incidence in mosquitoes, when incidence is calculated within 2.5–3 km and 50 days (credible interval 30–70 days) before onset of symptoms in humans. These measurements are in agreement with expected distances covered by mosquitoes and humans and the time for virus incubation. Finally, DENV incidence in mosquitoes found in the vicinity of infected humans correlated well with the low wind speed, higher air temperature and northerly winds that were more likely to favor vector survival and dispersal in Caratinga. Conclusions We have proposed a new way of modeling bivariate point pattern on the transmission of arthropod-borne pathogens between vector and host when the location of infection in the latter is known. This strategy avoids some of the strong and unrealistic assumptions made by other point-process models. Regarding virus transmission in Caratinga, our model showed a strong and significant association between high DENV incidence in mosquitoes and the onset of symptoms in humans at specific spatial and temporal windows. Together, our results indicate that vector surveillance must be a priority for dengue control. Nevertheless, localized vector control at distances lower than 2.5 km around premises with infected vectors in densely populated areas are not likely to be effective