Influence of climatic variables on the Aedes aegypti and Culex quinquefasciatus populations in Mato Grosso, Brazil (original) (raw)
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Memórias do Instituto Oswaldo Cruz, 2014
A longitudinal study was conducted in Manaus, Brazil, to monitor changes of adult Aedes aegypti (L.) abundance. The objectives were to compare mosquito collections of two trap types, to characterise temporal changes of the mosquito population, to investigate the influence of meteorological variables on mosquito collections and to analyse the association between mosquito collections and dengue incidence. Mosquito monitoring was performed fortnightly using MosquiTRAPs (MQT) and BG-Sentinel (BGS)
Tropical Medicine and Infectious Disease
Using collection methods for Aedes adults as surveillance tools provides reliable indices and arbovirus detection possibilities. This study compared the effectiveness of different methods for collecting Ae. aegypti and Ae. albopictus and detecting arboviruses circulating in field-caught female specimens. Collection sites were defined in urban, peri-urban, and rural landscapes in two Brazilian cities. Collections were performed using Adultraps (ADT), BG-Sentinel (BGS), CDC-like traps (CDC), and indoor (ASP-I) and outdoor (ASP-O) aspiration during the rainy and dry seasons of 2015 and 2016. Generalized linear mixed models were used to model the effectiveness of each collection method. A total of 434 Ae. aegypti and 393 Ae. albopictus were collected. In total, 64 Ae. aegypti and sixteen Ae. albopictus female pools were tested for DENV, CHIKV, ZIKV, or YFV; none were positive. Positivity and density were linear at low densities (<1 specimen); thereafter, the relationship became non-l...
The Open Tropical Medicine Journal, 2013
This study aimed to estimate the occurrence of Aedes aegypti adults at distinct climatic seasons at neighborhoods from the municipality of São Luís, Maranhão State, Brazil, as well as to verify the presence of Dengue virus (DENV) in the specimens collected. A total of 320 properties were visited in eight neighborhoods that were previously randomly chosen. Samplings were made at three periods: dry season/2008, rainy season/2009 and dry season/2009. A total of 563 Ae. aegypti mosquitoes were collected, with 141 of them collected during dry season/2008, 272 during rainy season/2009 and the remnant, during dry season/2009. Specimen were divided into lots and subjected to RT-semi-nested-PCR analysis and virus isolation was carried out using cell culture (C6/36 clone) of Ae. albopictus. The number of adults significantly varied at the neighborhoods of Coréia de Baixo, Lira, João Paulo, and Conjunto Cohatrac I. Molecular analyses of specimens showed no positivity for DENV. At the municipality of São Luís, seasonal climate variation might influence the density of Ae. aegypti adults, however, other factors such as population density, sanitation conditions, and the presence of mosquito breeding sites ought to be assessed as important parameters influencing vector dispersion.
Journal of Vector Ecology, 2016
The mosquito Aedes aegypti is the primary vector of dengue and is common throughout tropical and subtropical regions. Its distribution is modulated by environmental factors, such as temperature. This study aimed to evaluate the influence of temperature on the life cycle and expansion of Ae. aegypti populations in the cities of Campina Grande, João Pessoa, and Patos. Samples of Ae. aegypti were collected in the three cities and raised in the laboratory. We assessed the life cycles of the three Ae. aegypti populations under six constant temperatures (16, 22, 28, 33, 36, and 39° C), selected on the basis of historical temperature tendencies of each city. We also used existing climate data to calculate projected temperature increases for all three areas. Our results suggest that Campina Grande, João Pessoa, and Patos will experience, respectively, maximum temperature increases of 0.030° C/year, 0.069° C/year, and 0.061° C/year, and minimum temperature increases of 0.019° C/year,-0.047° C/year, and-0.086° C/year. These projected increases will result in temperatures favorable to the Ae. aegypti life cycle, causing rapid population growth. Therefore, Ae. aegypti populations are likely to expand in the mesoregions represented by these cities.
Journal of Medical Entomology, 2009
Dengue dynamics in Rio de Janeiro, Brazil, as in many dengue-endemic regions of the world, is seasonal, with peaks during the wetÐ hot months. This temporal pattern is generally attributed to the dynamics of its mosquito vector Aedes aegypti (L.). The objectives of this study were to characterize the temporal pattern of Ae. aegypti population dynamics in three neighborhoods of Rio de Janeiro and its association with local meteorological variables; and to compare positivity and density indices obtained with ovitraps and MosquiTraps. The three neighborhoods are distinct in vegetation coverage, sanitation, water supply, and urbanization. Mosquito sampling was carried out weekly, from September 2006 to March 2008, a period during which large dengue epidemics occurred in the city. Our results show peaks of oviposition in early summer 2007 and late summer 2008, detected by both traps. The ovitrap provided a more sensitive index than MosquiTrap. The MosquiTrap detection threshold showed high variation among areas, corresponding to a mean egg density of Ϸ25Ð52 eggs per ovitrap. Both temperature and rainfall were signiÞcantly related to Ae. aegypti indices at a short (1 wk) time lag. Our results suggest that mean weekly temperature above 22Ð24ЊC is strongly associated with high Ae. aegypti abundance and consequently with an increased risk of dengue transmission. Understanding the effects of meteorological variables on Ae. aegypti population dynamics will help to target control measures at the times when vector populations are greatest, contributing to the development of climate-based control and surveillance measures for dengue fever in a hyperendemic area. KEY WORDS population dynamics, Aedes aegypti, meteorological variables, dengue, traps Dengue is the most prevalent mosquito-borne viral disease in the world and an increasingly important cause of morbidity and mortality. Since the reinvasion of Brazil by the primary dengue vector Aedes aegypti (L.) in 1977, this country has experienced several dengue epidemics, with 4.5 million cases of dengue until 2008 (Ministé rio da Saú de 2008). Dengue was Þrst recognized in Brazil in 1981Ð1982, during an outbreak in the city of Boa Vista, Roraima, northern Brazil. In this outbreak, DENV-1 and DENV-4 serotypes were isolated, and 11,000 cases were conÞrmed (Osanai et al. 1983). Countrywide transmission of DENV-1 began only 4 yr later, when a large dengue epidemic started in metropolitan Rio de Janeiro. Rio de Janeiro was the port of entry for DENV-2 and DENV-3 into the country, in 1990 and 2001, respectively. In 2001Ð2002, DENV-3 caused a widespread
Memorias Do Instituto Oswaldo Cruz, 2009
Roraima is the northernmost state of Brazil, bordering both Venezuela and Guyana. Appropriate climate and vector conditions for dengue transmission together with its proximity to countries where all four dengue serotypes circulate make this state, particularly the capital Boa Vista, strategically important for dengue surveillance in Brazil. Nonetheless, few studies have addressed the population dynamics of Aedes aegypti in Boa Vista. In this study, we report temporal and spatial variations in Ae. aegypti population density using ovitraps in two highly populated neighbourhoods; Centro and Tancredo Neves. In three out of six surveys, Ae. aegypti was present in more than 80% of the sites visited. High presence levels of this mosquito suggest ubiquitous human exposure to the vector, at least during part of the year. The highest infestation rates occurred during the peak of the rainy seasons, but a large presence was also observed during the early dry season (although with more variation...
2018
Objective: In this study it was investigated the special distribution of Aedes mosquitoes with the use of ovitrap, in the city of Volta Redonda, Rio de Janeiro. Methodology: In order to obtain a representative population sample, three neighborhoods with different demographic characteristics were chosen: Aterrado (Urban), Jardim Amália (Transition zone) and Três Poços (Rural). Then it was established a stratum per neighborhood. Fifteen ovitraps were installed in each stratum. The IPO (Ovitrap Positivity Index) was used in order to analyze the vectors spacial distribution. The ovitraps were weekly monitored, during five weeks the vertical plywood panels (Eucatex® boards) containing eggs were colected, these were separated according to the place it was captured and later on analised in the Zoology laboratory of the UniFOA university. Results and Conclusions: It was possible to observe that the amount of eggs varied in a similar way in the three stratums analised, along the five weeks o...
Revista Brasileira de Entomologia, 2020
Aedes (Stegomyia) aegypti (A. aegypti) transmits arboviral diseases of high public health importance, including those caused by Zika virus (ZIKV), Dengue virus (DENV), Chikungunya virus (CHIKV) and Yellow fever virus (YFV). Barreiras is a city with 157,638 inhabitants in the West of the State of Bahia, Northeast of Brazil. The climate is dry, with well-determined and concentrated seasons of rains. The city is crossed by a Federal Highway and by the Rio Grande river. In this study, we aimed to understand the dynamics of mosquito vectors and arboviral diseases in Barreiras. We used correlation statistics to investigate a possible relationship among rains, mosquito abundance and transmission of diseases. In addition, as a preliminary population genetics estimate, we used geometric morphometrics to compare mosquitoes from areas limited by a highway and a river. We found that i) infestation occurs in rain-dependent cycles and that ii) both, the river and the highway segregate populations of A. aegypti in different areas of the studied city. Our results indicate that it is necessary to treat anthropic containers with mosquito breading capacity during both, the dry and rain seasons in urban areas similar to Barreiras.
Background: Measure the populations of Ae. aegypti and Ae. albopictus adults according to sex and location inside or outside the residence, estimate Ae. aegypti female density per house and per resident, and test the association with abiotic factors. Methods: Adult mosquitoes were collected monthly with a hand net and portable electric catcher in the peridomiciliary and intradomiciliary premises of residences in an urban area with ongoing dengue transmission in the municipality of São Sebastião, Brazil, from February 2011 to February 2012. Results: Of the 1,320 specimens collected, 1,311 were Ae. aegypti, and nine were Ae. albopictus. A total of 653 male and 658 female of Ae. aegypti were recorded, of which 80% were intradomiciliary. The mean density of Ae. aegypti adult females was 1.60 females/house and 0.42 females/resident. There was an association between the number of females and the number of residents in both intradomiciliary and peridomiciliary premises (r2 = 0.92; p < 0.001 and r2 = 0.68; p < 0.001, respectively). There was an association between the number of females and the mean and total rainfall; the correlation was better in peridomiciliary premises (p = 0.00; r2 = 77%) than intradomiciliary premises in both cases (p = 0.01; r2 = 48%). Minimum temperature was associated in both environments, exhibiting the same coefficient of determination (p = 0.02; r2 = 40%). The low frequency of Ae. albopictus (seven females and two males) did not allow for detailed evaluation. Conclusions: Ae. aegypti is well established within the urban area studied, and the frequency of isolation is higher inside the houses. Female density was directly proportional to the number of residents in the houses. Our data show that human population density positively affects the number of Ae. aegypti females within the residence. Meteorological variables also affected mosquito populations. These data indicate a high probability of human-vector contact, increasing the possible transmission and spread of the DEN virus. Entomological indicators of adult females revealed important information complimenting what was obtained with traditional Stegomyia indices. This information should be a part of an interconnected data set for evaluating and controlling the vector. Keywords: Aedes aegypti, Vector control, Culicidae, Dengue, Entomological indicator, Meteorological