scholarly journals Increasing Role of Roof Gutters asAedes aegypti(Diptera: Culicidae) Breeding Sites in Guadeloupe (French West Indies) and Consequences on Dengue Transmission and Vector Control

2012 ◽  
Vol 2012 ◽  
pp. 1-3 ◽  
Author(s):  
Joël Gustave ◽  
Florence Fouque ◽  
Sylvie Cassadou ◽  
Lucie Leon ◽  
Gabriel Anicet ◽  
...  

During the past ten years, the islands of Guadeloupe (French West Indies) are facing dengue epidemics with increasing numbers of cases and fatal occurrences. The vectorAedes aegyptiis submitted to intensive control, with little effect on mosquito populations. The hypothesis that importantAe. aegyptibreeding sites are not controlled is investigated herein. For that purpose, the roof gutters of 123 houses were systematically investigated, and the percentage of gutters positive forAe. aegyptivaried from 17.2% to 37.5%, from humid to dry locations. In the dryer location, most of houses had no other breeding sites. The results show that roof gutters are becoming the most importantAe. aegyptibreeding sites in some locations in Guadeloupe, with consequences on dengue transmission and vector control.

Author(s):  
Melisa B Bonica ◽  
Dario E Balcazar ◽  
Ailen Chuchuy ◽  
Jorge A Barneche ◽  
Carolina Torres ◽  
...  

Abstract Diseases caused by flaviviruses are a major public health burden across the world. In the past decades, South America has suffered dengue epidemics, the re-emergence of yellow fever and St. Louis encephalitis viruses, and the introduction of West Nile and Zika viruses. Many insect-specific flaviviruses (ISFs) that cannot replicate in vertebrate cells have recently been described. In this study, we analyzed field-collected mosquito samples from six different ecoregions of Argentina to detect flaviviruses. We did not find any RNA belonging to pathogenic flaviviruses or ISFs in adults or immature stages. However, flaviviral-like DNA similar to flavivirus NS5 region was detected in 83–100% of Aedes aegypti (L.). Despite being previously described as an ancient element in the Ae. aegypti genome, the flaviviral-like DNA sequence was not detected in all Ae. aegypti samples and sequences obtained did not form a monophyletic group, possibly reflecting the genetic diversity of mosquito populations in Argentina.


2020 ◽  
Author(s):  
Thien-An Ha ◽  
Tomás M. León ◽  
Karina Lalangui ◽  
Patricio Ponce ◽  
John M. Marshall ◽  
...  

AbstractBackgroundVector-borne diseases are a major cause of disease burden in Guayaquil, Ecuador, especially arboviruses spread by Aedes aegypti mosquitoes. Understanding which household characteristics and risk factors lead to higher Ae. aegypti densities and consequent disease risk can help inform and optimize vector control programs.MethodsCross-sectional entomological surveys were conducted in Guayaquil between 2013 and 2016, covering household demographics, municipal services, potential breeding containers, presence of Ae. aegypti larvae and pupae, and history of using mosquito control methods. A zero-truncated negative binomial regression model was fitted to data for estimating the household pupal index. An additional model assessed the factors of the most productive breeding sites across all of the households.ResultsOf surveyed households, 610 satisfied inclusion criteria. The final household-level model found that collection of large solid items (e.g., furniture and tires) and rainfall the week of and 2 weeks before collection were negatively correlated with average pupae per container, while bed canopy use, unemployment, container water volume, and the interaction between large solid collection and rainfall 2 weeks before the sampling event were positively correlated. Selection of these variables across other top candidate models with ΔAICc < 1 was robust, with the strongest effects from large solid collection and bed canopy use. The final container-level model explaining the characteristics of breeding sites found that contaminated water is positively correlated with Ae. aegypti pupae counts while breeding sites composed of car parts, furniture, sewerage parts, vases, ceramic material, glass material, metal material, and plastic material were all negatively correlated.ConclusionHaving access to municipal services like bulky item pickup was effective at reducing mosquito proliferation in households. Association of bed canopy use with higher mosquito densities is unexpected, and may be a consequence of large local mosquito populations or due to limited use or effectiveness of other vector control methods. The impact of rainfall on mosquito density is multifaceted, as it may both create new habitat and “wash out” existing habitat. Providing services and social/technical interventions focused on monitoring and eliminating productive breeding sites is important for reducing aquatic-stage mosquito densities in households at risk for Ae. aegypti-transmitted diseases.


2019 ◽  
Vol 53 ◽  
pp. 29 ◽  
Author(s):  
Gerson Laurindo Barbosa ◽  
Mariana De Oliveira Lage ◽  
Valmir Roberto Andrade ◽  
Antônio Henrique Alves Gomes ◽  
Jose Alberto Quintanilha ◽  
...  

OBJECTIVE: To evaluate whether sites with large amount of potential breeding sites for immature forms of Aedes aegypti, called strategic points, influence in the active vector’s dispersion into properties in their surroundings. METHODS: We selected four areas in the municipality of Campinas, three of them with strategic points classified as high, moderate, and low risk according to infestation and a control area, without strategic points. Between October 2015 and September 2016, we monthly installed oviposition traps and evaluated the infestation by Ae. aegypti in all properties of each selected area. To verify if there was vector dispersion from each strategic point, based on its location, we investigated the formation of clusters with excess of eggs or larvae or pupae containers, using the Gi spatial statistics. RESULTS: The amount of eggs collected in the ovitraps and the number of positive containers for Ae. aegypti did not show clusters of high values concerning its distance from the strategic point. Both presented random distribution not spatially associated with the positioning of strategic points in the area. CONCLUSIONS: Strategic points are not confirmed as responsible for the vector’s dispersion for properties in their surroundings. We highlight the importance of reviewing the current strategy of the vector control program in Brazil, seeking a balance from the technical, operational, and economic point of view, without disregarding the role of strategic points as major producers of mosquitoes and their importance in the dissemination of arboviruses in periods of transmission.


2019 ◽  
Vol 56 (4) ◽  
pp. 1078-1086 ◽  
Author(s):  
Nancy M Endersby-Harshman ◽  
Jason K Axford ◽  
Ary A Hoffmann

Abstract Wolbachia-infected Aedes aegypti (L.) mosquitoes for control of dengue transmission are being released experimentally in tropical regions of Australia, south-east Asia, and South America. To become established, the Wolbachia Hertig (Rickettsiales: Rickettsiaceae) strains used must induce expression of cytoplasmic incompatibility (CI) in matings between infected males and uninfected females so that infected females have a reproductive advantage, which will drive the infection through field populations. Wolbachia is a Rickettsia-like alphaproteobacterium which can be affected by tetracycline antibiotics. We investigated whether exposure of Wolbachia-infected mosquitoes to chlortetracycline at environmentally relevant levels during their aquatic development resulted in loss or reduction of infection in three strains, wAlbB, wMel, and wMelPop. Wolbachia density was reduced for all three strains at the tested chlortetracycline concentrations of 5 and 50 µg/liter. Two of the strains, wMel and wMelPop, showed a breakdown in CI. The wAlbB strain maintained CI and may be useful at breeding sites where tetracycline contamination has occurred. This may include drier regions where Ae. aegypti can utilize subterranean water sources and septic tanks as breeding sites.


2019 ◽  
Vol 286 (1914) ◽  
pp. 20192136 ◽  
Author(s):  
David P. Tchouassi ◽  
Juliah W. Jacob ◽  
Edwin O. Ogola ◽  
Rosemary Sang ◽  
Baldwyn Torto

Interactions between Aedes ( Stegomyia ) species and non-human primate (NHP) and human hosts govern the transmission of the pathogens, dengue, zika, yellow fever and chikungunya viruses. Little is known about Aedes mosquito olfactory interactions with these hosts in the domestic and sylvatic cycles where these viruses circulate. Here, we explore how the different host-derived skin odours influence Aedes mosquito responses in these two environments. In field assays, we show that the cyclic ketone cyclohexanone is a signature cue for Aedes mosquitoes to detect the NHP baboon, sykes and vervet, whereas for humans, it is the unsaturated aliphatic keto-analogue 6-methyl-5-hepten-2-one (sulcatone). We find that in the sylvatic environment, CO 2 -baited traps combined with either cyclohexanone or sulcatone increased trap catches of Aedes mosquitoes compared to traps either baited with CO 2 alone or CO 2 combined with NHP- or human-derived crude skin odours. In the domestic environment, each of these odourants and crude human skin odours increased Aedes aegypti catches in CO 2 -baited traps. These results expand our knowledge on the role of host odours in the ecologies of Aedes mosquitoes, and the likelihood of associated spread of pathogens between primates and humans. Both cyclohexanone and sulcatone have potential practical applications as lures for monitoring Aedes disease vectors.


2010 ◽  
Vol 16 (1) ◽  
pp. 134-139 ◽  
Author(s):  
Romain Girod ◽  
Pascal Gaborit ◽  
Laurence Marrama ◽  
Manuel Etienne ◽  
Cédric Ramdini ◽  
...  

BMC Genomics ◽  
2009 ◽  
Vol 10 (1) ◽  
pp. 494 ◽  
Author(s):  
Sébastien Marcombe ◽  
Rodolphe Poupardin ◽  
Frederic Darriet ◽  
Stéphane Reynaud ◽  
Julien Bonnet ◽  
...  

2011 ◽  
Vol 84 (1) ◽  
pp. 118-126 ◽  
Author(s):  
Sébastien Marcombe ◽  
Vincent Corbel ◽  
André Yébakima ◽  
Manuel Etienne ◽  
Marie-Michelle Yp-Tcha ◽  
...  

2020 ◽  
Author(s):  
Elizabet L. Estallo ◽  
Rachel Sippy ◽  
Anna M. Stewart-Ibarra ◽  
Marta G. Grech ◽  
Elisabet M. Benitez ◽  
...  

AbstractBackgroundArgentina is located at the southern temperate range of arboviral transmission by the mosquito Aedes aegypti and has experienced a rapid increase in disease transmission in recent years. Here we present findings from an entomological surveillance study that began in Córdoba, Argentina, following the emergence of dengue in 2009.MethodsFrom 2009 to 2017, larval surveys were conducted monthly, from November to May, in 600 randomly selected households distributed across the city. From 2009 to 2013, ovitraps (n=177) were sampled weekly to monitor the oviposition activity of Ae. aegypti. We explored seasonal and interannual dynamics of entomological variables and dengue transmission. Cross correlation analysis was used to identify significant lag periods.ResultsAedes aegypti were detected over the entire study period, and abundance peaked during the summer months (January to March). We identified a considerable increase in the proportion of homes with juvenile Ae. aegypti over the study period (from 5.7% of homes in 2009-10 to 15.4% of homes in 2016-17). Aedes aegypti eggs per ovitrap and larval abundance were positively associated with temperature in the same month. Autochthonous dengue transmission peaked in April, following a peak in imported dengue cases in March; autochthonous dengue was not positively associated with vector or climate variables.ConclusionsThis longitudinal study provides insights into the complex dynamics of arbovirus transmission and vector populations in a temperate region of arbovirus emergence. Our findings suggest that Córdoba is well suited for arbovirus disease transmission, given the stable and abundant vector populations. Further studies are needed to better understand the role of regional human movement.Author summaryThere is an increasing risk of arbovirus transmission in temperate regions. Argentina is located at the southern range of dengue virus transmission by the Aedes aegypti mosquito. In the last decade, epidemics of dengue fever have emerged for the first time in the city of Córdoba, Argentina. We present the study design and findings from an entomological surveillance study in Córdoba, which began following the emergence of dengue in 2009. We found that Ae. aegypti were most abundant from January to March, followed by a peak in local dengue transmission in April. Over the study period, we noted a considerable increase in the proportion of homes with Ae. aegypti. Vector indices were positively associated with warmer temperatures, which have been increasing in this region. However, the timing of local dengue transmission appears to be driven by the appearance of imported dengue cases associated with human movement. These results highlight the important role of long term surveillance studies in areas of disease emergence.


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