Changes in the Genetic Structure of Aedes aegypti (Diptera: Culicidae) Populations in Queensland, Australia, Across Two Seasons: Implications for Potential Mosquito Releases

PubMed Central

ENDERSBY, N. M.; HOFFMANN, A. A.; WHITE, V. L.; RITCHIE, S. A.; JOHNSON, P. H.; WEEKS, A. R.

2012-01-01

Diseases transmitted by mosquitoes could be controlled if vector populations were replaced with strains that have reduced vector competency. Such a strategy is being developed for control of dengue virus which is transmitted by Aedes aegypti (L.) (Diptera: Culicidae). Mosquitoes artificially infected with the bacterium, Wolbachia pipientis Hertig, are being assessed as candidates for release at the adult stage with the aim of replacement of the wild population. Wolbachia can reduce the capacity of Ae. aegypti to transmit dengue virus and has potential to be driven through the natural population via a system of cytoplasmic incompatibility. Deployment of benign mosquito strains will be influenced by population size and structure of wild-type Ae. aegypti in proposed release areas, as well as rates of gene flow among populations in the wet and dry tropical seasons. Mosquitoes from northern Queensland were screened with genetic markers to find an optimal locality for release of a benign strain of Ae. aegypti. The inland towns of Chillagoe and Charters Towers and the coastal town of Ingham had mosquito populations that were partly genetically isolated from mosquitoes in other areas across both seasons. These locations may be suitable release sites if it is important for the released strain to be restricted during initial phases of implementation. Smaller genetic differences were also evident among other regions and were consistent over two seasons (wet and dry). PMID:21936318

Threshold Dynamics of a Temperature-Dependent Stage-Structured Mosquito Population Model with Nested Delays.

PubMed

Wang, Xiunan; Zou, Xingfu

2018-05-21

Mosquito-borne diseases remain a significant threat to public health and economics. Since mosquitoes are quite sensitive to temperature, global warming may not only worsen the disease transmission case in current endemic areas but also facilitate mosquito population together with pathogens to establish in new regions. Therefore, understanding mosquito population dynamics under the impact of temperature is considerably important for making disease control policies. In this paper, we develop a stage-structured mosquito population model in the environment of a temperature-controlled experiment. The model turns out to be a system of periodic delay differential equations with periodic delays. We show that the basic reproduction number is a threshold parameter which determines whether the mosquito population goes to extinction or remains persistent. We then estimate the parameter values for Aedes aegypti, the mosquito that transmits dengue virus. We verify the analytic result by numerical simulations with the temperature data of Colombo, Sri Lanka where a dengue outbreak occurred in 2017.

Adult Survivorship of the Dengue Mosquito Aedes aegypti Varies Seasonally in Central Vietnam

PubMed Central

Hugo, Leon E.; Jeffery, Jason A. L.; Trewin, Brendan J.; Wockner, Leesa F.; Thi Yen, Nguyen; Le, Nguyen Hoang; Nghia, Le Trung; Hine, Emma; Ryan, Peter A.; Kay, Brian H.

2014-01-01

The survival characteristics of the mosquito Aedes aegypti affect transmission rates of dengue because transmission requires infected mosquitoes to survive long enough for the virus to infect the salivary glands. Mosquito survival is assumed to be high in tropical, dengue endemic, countries like Vietnam. However, the survival rates of wild populations of mosquitoes are seldom measured due the difficulty of predicting mosquito age. Hon Mieu Island in central Vietnam is the site of a pilot release of Ae. aegypti infected with a strain of Wolbachia pipientis bacteria (wMelPop) that induces virus interference and mosquito life-shortening. We used the most accurate mosquito age grading approach, transcriptional profiling, to establish the survival patterns of the mosquito population from the population age structure. Furthermore, estimations were validated on mosquitoes released into a large semi-field environment consisting of an enclosed house, garden and yard to incorporate natural environmental variability. Mosquito survival was highest during the dry/cool (January-April) and dry/hot (May-August) seasons, when 92 and 64% of Hon Mieu mosquitoes had survived to an age that they were able to transmit dengue (12 d), respectively. This was reduced to 29% during the wet/cool season from September to December. The presence of Ae. aegypti older than 12 d during each season is likely to facilitate the observed continuity of dengue transmission in the region. We provide season specific Ae. aegypti survival models for improved dengue epidemiology and evaluation of mosquito control strategies that aim to reduce mosquito survival to break the dengue transmission cycle. PMID:24551251

Mosquito Surveillance for Prevention and Control of Emerging Mosquito-Borne Diseases in Portugal — 2008–2014

PubMed Central

Osório, Hugo C.; Zé-Zé, Líbia; Amaro, Fátima; Alves, Maria J.

2014-01-01

Mosquito surveillance in Europe is essential for early detection of invasive species with public health importance and prevention and control of emerging pathogens. In Portugal, a vector surveillance national program—REVIVE (REde de VIgilância de VEctores)—has been operating since 2008 under the custody of Portuguese Ministry of Health. The REVIVE is responsible for the nationwide surveillance of hematophagous arthropods. Surveillance for West Nile virus (WNV) and other flaviviruses in adult mosquitoes is continuously performed. Adult mosquitoes—collected mainly with Centre for Disease Control light traps baited with CO2—and larvae were systematically collected from a wide range of habitats in 20 subregions (NUTS III). Around 500,000 mosquitoes were trapped in more than 3,000 trap nights and 3,500 positive larvae surveys, in which 24 species were recorded. The viral activity detected in mosquito populations in these years has been limited to insect specific flaviviruses (ISFs) non-pathogenic to humans. Rather than emergency response, REVIVE allows timely detection of changes in abundance and species diversity providing valuable knowledge to health authorities, which may take control measures of vector populations reducing its impact on public health. This work aims to present the REVIVE operation and to expose data regarding mosquito species composition and detected ISFs. PMID:25396768

Methionine: a new biopesticide for use in mosquito management

USDA-ARS?s Scientific Manuscript database

Mosquito larvicides are an effective means of source reduction, controlling the population size so that the number of adult females that are present to bite and potentially spread pathogenic organisms is decreased. Currently utilized mosquito larvicides include insect growth regulators, organophosph...

Anthropogenic impacts on mosquito populations in North America over the past century

NASA Astrophysics Data System (ADS)

Rochlin, Ilia; Faraji, Ary; Ninivaggi, Dominick V.; Barker, Christopher M.; Kilpatrick, A. Marm

2016-12-01

The recent emergence and spread of vector-borne viruses including Zika, chikungunya and dengue has raised concerns that climate change may cause mosquito vectors of these diseases to expand into more temperate regions. However, the long-term impact of other anthropogenic factors on mosquito abundance and distributions is less studied. Here, we show that anthropogenic chemical use (DDT; dichlorodiphenyltrichloroethane) and increasing urbanization were the strongest drivers of changes in mosquito populations over the last eight decades in areas on both coasts of North America. Mosquito populations have increased as much as tenfold, and mosquito communities have become two- to fourfold richer over the last five decades. These increases are correlated with the decay in residual environmental DDT concentrations and growing human populations, but not with temperature. These results illustrate the far-reaching impacts of multiple anthropogenic disturbances on animal communities and suggest that interactions between land use and chemical use may have unforeseen consequences on ecosystems.

The Role of Climatic and Density Dependent Factors in Shaping Mosquito Population Dynamics: The Case of Culex pipiens in Northwestern Italy

PubMed Central

Giacobini, Mario; Pugliese, Andrea; Merler, Stefano; Rosà, Roberto

2016-01-01

Culex pipiens mosquito is a species widely spread across Europe and represents a competent vector for many arboviruses such as West Nile virus (WNV), which has been recently circulating in many European countries, causing hundreds of human cases. In order to identify the main determinants of the high heterogeneity in Cx. pipiens abundance observed in Piedmont region (Northwestern Italy) among different seasons, we developed a density-dependent stochastic model that takes explicitly into account the role played by temperature, which affects both developmental and mortality rates of different life stages. The model was calibrated with a Markov chain Monte Carlo approach exploring the likelihood of recorded capture data gathered in the study area from 2000 to 2011; in this way, we disentangled the role played by different seasonal eco-climatic factors in shaping the vector abundance. Illustrative simulations have been performed to forecast likely changes if temperature or density–dependent inputs would change. Our analysis suggests that inter-seasonal differences in the mosquito dynamics are largely driven by different temporal patterns of temperature and seasonal-specific larval carrying capacities. Specifically, high temperatures during early spring hasten the onset of the breeding season and increase population abundance in that period, while, high temperatures during the summer can decrease population size by increasing adult mortality. Higher densities of adult mosquitoes are associated with higher larval carrying capacities, which are positively correlated with spring precipitations. Finally, an increase in larval carrying capacity is expected to proportionally increase adult mosquito abundance. PMID:27105065

Identification of environmental covariates of West Nile virus vector mosquito population abundance.

PubMed

Trawinski, Patricia R; Mackay, D Scott

2010-06-01

The rapid spread of West Nile virus (WNv) in North America is a major public health concern. Culex pipiens-restuans is the principle mosquito vector of WNv in the northeastern United States while Aedes vexans is an important bridge vector of the virus in this region. Vector mosquito abundance is directly dependent on physical environmental factors that provide mosquito habitats. The objective of this research is to determine landscape elements that explain the population abundance and distribution of WNv vector mosquitoes using stepwise linear regression. We developed a novel approach for examining a large set of landscape variables based on a land use and land cover classification by selecting variables in stages to minimize multicollinearity. We also investigated the distance at which landscape elements influence abundance of vector populations using buffer distances of 200, 400, and 1000 m. Results show landscape effects have a significant impact on Cx. pipiens-estuans population distribution while the effects of landscape features are less important for prediction of Ae. vexans population distributions. Cx. pipiens-restuans population abundance is positively correlated with human population density, housing unit density, and urban land use and land cover classes and negatively correlated with age of dwellings and amount of forested land.

Mosquitoes Transmit Unique West Nile Virus Populations during Each Feeding Episode.

PubMed

Grubaugh, Nathan D; Fauver, Joseph R; Rückert, Claudia; Weger-Lucarelli, James; Garcia-Luna, Selene; Murrieta, Reyes A; Gendernalik, Alex; Smith, Darci R; Brackney, Doug E; Ebel, Gregory D

2017-04-25

Arthropod-borne viruses (arboviruses), such as Zika virus, chikungunya virus, and West Nile virus (WNV), pose continuous threats to emerge and cause large epidemics. Often, these events are associated with novel virus variants optimized for local transmission that first arise as minorities within a host. Thus, the conditions that regulate the frequency of intrahost variants are important determinants of emergence. Here, we describe the dynamics of WNV genetic diversity during its transmission cycle. By temporally sampling saliva from individual mosquitoes, we demonstrate that virus populations expectorated by mosquitoes are highly diverse and unique to each feeding episode. After transmission to birds, however, most genetic diversity is removed by strong purifying selection. Further, transmission of potentially mosquito-adaptive WNV variants is strongly influenced by genetic drift in mosquitoes. These results highlight the complex evolutionary forces a novel virus variant must overcome to alter infection phenotypes at the population level. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Satellite Microwave Remote Sensing for Environmental Modeling of Mosquito Population Dynamics

PubMed Central

Chuang, Ting-Wu; Henebry, Geoffrey M.; Kimball, John S.; VanRoekel-Patton, Denise L.; Hildreth, Michael B.; Wimberly, Michael C.

2012-01-01

Environmental variability has important influences on mosquito life cycles and understanding the spatial and temporal patterns of mosquito populations is critical for mosquito control and vector-borne disease prevention. Meteorological data used for model-based predictions of mosquito abundance and life cycle dynamics are typically acquired from ground-based weather stations; however, data availability and completeness are often limited by sparse networks and resource availability. In contrast, environmental measurements from satellite remote sensing are more spatially continuous and can be retrieved automatically. This study compared environmental measurements from the NASA Advanced Microwave Scanning Radiometer on EOS (AMSR-E) and in situ weather station data to examine their ability to predict the abundance of two important mosquito species (Aedes vexans and Culex tarsalis) in Sioux Falls, South Dakota, USA from 2005 to 2010. The AMSR-E land parameters included daily surface water inundation fraction, surface air temperature, soil moisture, and microwave vegetation opacity. The AMSR-E derived models had better fits and higher forecasting accuracy than models based on weather station data despite the relatively coarse (25-km) spatial resolution of the satellite data. In the AMSR-E models, air temperature and surface water fraction were the best predictors of Aedes vexans, whereas air temperature and vegetation opacity were the best predictors of Cx. tarsalis abundance. The models were used to extrapolate spatial, seasonal, and interannual patterns of climatic suitability for mosquitoes across eastern South Dakota. Our findings demonstrate that environmental metrics derived from satellite passive microwave radiometry are suitable for predicting mosquito population dynamics and can potentially improve the effectiveness of mosquito-borne disease early warning systems. PMID:23049143

Entomopathogenic fungi for mosquito control: A review

PubMed Central

Scholte, Ernst-Jan; Knols, Bart G.J.; Samson, Robert A.; Takken, Willem

2004-01-01

Fungal diseases in insects are common and widespread and can decimate their populations in spectacular epizootics. Virtually all insect orders are susceptible to fungal diseases, including Dipterans. Fungal pathogens such as Lagenidium, Coelomomyces and Culicinomyces are known to affect mosquito populations, and have been studied extensively. There are, however, many other fungi that infect and kill mosquitoes at the larval and/or adult stage. The discovery, in 1977, of the selective mosquito-pathogenic bacterium Bacillus thuringiensis Berliner israelensis (Bti) curtailed widespread interest in the search for other suitable biological control agents. In recent years interest in mosquito-killing fungi is reviving, mainly due to continuous and increasing levels of insecticide resistance and increasing global risk of mosquito-borne diseases. This review presents an update of published data on mosquito-pathogenic fungi and mosquito-pathogen interactions, covering 13 different fungal genera. Notwithstanding the potential of many fungi as mosquito control agents, only a handful have been commercialized and are marketed for use in abatement programs. We argue that entomopathogenic fungi, both new and existing ones with renewed/improved efficacies may contribute to an expansion of the limited arsenal of effective mosquito control tools, and that they may contribute in a significant and sustainable manner to the control of vector-borne diseases such as malaria, dengue and filariasis. PMID:15861235

Mosquito Larvae in Tires from Mississippi, United States: The Efficacy of Abiotic and Biotic Parameters in Predicting Spatial and Temporal Patterns of Mosquito Populations and Communities

PubMed Central

Yee, Donald A.; Abuzeineh, Alisa A.; Ezeakacha, Nnaemeka F.; Schelble, Stephanie S.; Glasgow, William C.; Flanagan, Stephen D.; Skiff, Jeffrey J.; Reeves, Ashton; Kuehn, Kevin

2015-01-01

Container systems, including discarded vehicle tires, which support populations of mosquitoes, have been of interest for understanding the variables that produce biting adults that serve as both nuisances and as public health threats. We sampled tires in six sites at three times in 2012 across the state of Mississippi to understand the biotic and abiotic variables responsible for explaining patterns of larvae of common species, species richness, and total abundance of mosquitoes. From 498 tires sampled, we collected >58,000 immatures representing 16 species, with the most common species including Aedes albopictus (Skuse), Culex quinquefasciatus (L.), Orthopodomyia signifera (Coquillett), Aedes triseriatus (Say), Toxorhynchites rutilus septentrionalis (Coquillett), and Culex territans (Walker) accounting for ∼97% of all larvae. We also documented 32 new county records for resident species and recent arrivals in the state, including Aedes japonicus japonicus (Theobald) and Culex coronator (Dyar & Knab). Cluster analysis, which was used to associate sites and time periods based on similar mosquito composition, did reveal patterns across the state; however, there also were more general patterns between species and genera and environmental factors. Broadly, Aedes was often associated with factors related to detritus, whereas Culex was frequently associated with habitat variables (e.g., tire size and water volume) and microorganisms. Some Culex did lack factors connecting variation in early and late instars, suggesting differences between environmental determinants of oviposition and survival. General patterns between the tire environment and mosquito larvae do appear to exist, especially at the generic level, and point to inherent differences between genera that may aid in predicting vector locations and populations. PMID:26334813

Monitoring Malaria Vector Control Interventions: Effectiveness of Five Different Adult Mosquito Sampling Methods

PubMed Central

Onyango, Shirley A.; Kitron, Uriel; Mungai, Peter; Muchiri, Eric M.; Kokwaro, Elizabeth; King, Charles H.; Mutuku, Francis M.

2014-01-01

Long-term success of ongoing malaria control efforts based on mosquito bed nets (long-lasting insecticidal net) and indoor residual spraying is dependent on continuous monitoring of mosquito vectors, and thus on effective mosquito sampling tools. The objective of our study was to identify the most efficient mosquito sampling tool(s) for routine vector surveillance for malaria and lymphatic filariasis transmission in coastal Kenya. We evaluated relative efficacy of five collection methods—light traps associated with a person sleeping under a net, pyrethrum spray catches, Prokopack aspirator, clay pots, and urine-baited traps—in four villages representing three ecological settings along the south coast of Kenya. Of the five methods, light traps were the most efficient for collecting female Anopheles gambiae s.l. (Giles) (Diptera: Culicidae) and Anopheles funestus (Giles) (Diptera: Culicidae) mosquitoes, whereas the Prokopack aspirator was most efficient in collecting Culex quinquefasciatus (Say) (Diptera: Culicidae) and other culicines. With the low vector densities here, and across much of sub-Saharan Africa, wherever malaria interventions, long-lasting insecticidal nets, and/or indoor residual spraying are in place, the use of a single mosquito collection method will not be sufficient to achieve a representative sample of mosquito population structure. Light traps will remain a relevant tool for host-seeking mosquitoes, especially in the absence of human landing catches. For a fair representation of the indoor mosquito population, light traps will have to be supplemented with aspirator use, which has potential for routine monitoring of indoor resting mosquitoes, and can substitute the more labor-intensive and intrusive pyrethrum spray catches. There are still no sufficiently efficient mosquito collection methods for sampling outdoor mosquitoes, particularly those that are bloodfed. PMID:24180120

A web-based relational database for monitoring and analyzing mosquito population dynamics.

PubMed

Sucaet, Yves; Van Hemert, John; Tucker, Brad; Bartholomay, Lyric

2008-07-01

Mosquito population dynamics have been monitored on an annual basis in the state of Iowa since 1969. The primary goal of this project was to integrate light trap data from these efforts into a centralized back-end database and interactive website that is available through the internet at http://iowa-mosquito.ent.iastate.edu. For comparative purposes, all data were categorized according to the week of the year and normalized according to the number of traps running. Users can readily view current, weekly mosquito abundance compared with data from previous years. Additional interactive capabilities facilitate analyses of the data based on mosquito species, distribution, or a time frame of interest. All data can be viewed in graphical and tabular format and can be downloaded to a comma separated value (CSV) file for import into a spreadsheet or more specialized statistical software package. Having this long-term dataset in a centralized database/website is useful for informing mosquito and mosquito-borne disease control and for exploring the ecology of the species represented therein. In addition to mosquito population dynamics, this database is available as a standardized platform that could be modified and applied to a multitude of projects that involve repeated collection of observational data. The development and implementation of this tool provides capacity for the user to mine data from standard spreadsheets into a relational database and then view and query the data in an interactive website.

West Nile Virus in Mosquitoes of Iranian Wetlands.

PubMed

Bagheri, Masoomeh; Terenius, Olle; Oshaghi, Mohammad Ali; Motazakker, Morteza; Asgari, Sassan; Dabiri, Farrokh; Vatandoost, Hassan; Mohammadi Bavani, Mulood; Chavshin, Ali Reza

2015-12-01

The West Nile virus (WNV) transmission cycle includes a wide range of migratory wetland birds as reservoirs, mosquitoes as biological vectors, and equines and humans as dead-end hosts. Despite the presence of potential vector species, there is no information about the existence of WNV in mosquito vectors in Iran. The Iranian West Azerbaijan Province is located in the northwestern part of Iran and has borders with Turkey, Iraq, Armenia, and the Republic of Azerbaijan. The current study was conducted to identify the wetland mosquitoes of the West Azerbaijan Province and their infection with WNV. In this study, 2143 specimens were collected, comprising 1541 adults and 602 larvae. Six species belonging to four genera were collected and identified: Anopheles maculipennis sensu lato (s.l.), Culex (Cx.) hortensis, Cx. pipiens s.l., Cx. theileri, Culiseta longiareolata, and Aedes (Ae.) (Ochlerotatus) caspius. In total, 45 pools of mosquitoes were examined. Two of the adult pools collected from the same location showed the presence of WNV in Ae. (Och.) caspius, from Sangar, Makoo County, as confirmed by PCR and sequencing. Due to the discovery of WNV in the mosquito population of the region, and the presence of wetlands and significant populations of migratory birds, the health sector should carefully monitor the factors involved in the cycle of this disease.

Use and effectiveness of commercial flit-spray insecticides in control of mosquito population in Sagamu, Southwest Nigeria.

PubMed

Adedeji, A A; Ahmed, I A; Akinwunmi, M; Aina, S A; Tikare, O; Adeboye, A F; Badmos, S O; Adedeji, K A; Fehintola, F A; Amoo, A O J

2012-06-01

Control of mosquito vector is crucial to reducing the burden of malaria in endemic region. In the present study, we investigated the use of commercial insecticides in families and their effectiveness in control of mosquito population in Sagamu, southwest Nigeria. A pretested structured questionnaire was used to determine mosquito adulticides techniques employed in the community and most commonly used adulticides were evaluated for effectiveness by exposing adult mosquitoes to varying concentrations of the insecticides and responses monitored. Families differ in methods adopted to prevent mosquito and use of flit-spray insecticide was commoner. Although parents constitute 64% of those applying the insecticide, 22.2% were children. Household pyrethroid insecticide products of Baygon (Imiprothrin, Prallethrin plus Cyfluthrin), Mobil (Neopynamin, Prallethrin plus Cyphenothrin) and Raid (Pynamin forte, Neopynamin plus Deltimethrin) were three commonly used in the community. The exposure tie interval for eath of osquitoes was shorter with Raid (100% at 8 minutes) when compared with Mobil (80%) and Baygon (85%) at 10 minutes (p = 0.005). Kaplan-Meier survival curve of cumulative probability of surviving exposure to insecticide was lowest with Raid (log rank 2 = 14.56, P = 0.001). Although flit-spray insecticides are affordable with simple application tool, inexplicit use-instruction on labels may cause discrepancies in application. Monitoring responses of mosquitoes to commercial flit-spray insecticide may support effective control technique and prevention of vector resistance in poor resource communities.

Transcriptome of the adult female malaria mosquito vector Anopheles albimanus.

PubMed

Martínez-Barnetche, Jesús; Gómez-Barreto, Rosa E; Ovilla-Muñoz, Marbella; Téllez-Sosa, Juan; García López, David E; Dinglasan, Rhoel R; Ubaida Mohien, Ceereena; MacCallum, Robert M; Redmond, Seth N; Gibbons, John G; Rokas, Antonis; Machado, Carlos A; Cazares-Raga, Febe E; González-Cerón, Lilia; Hernández-Martínez, Salvador; Rodríguez López, Mario H

2012-05-30

Human Malaria is transmitted by mosquitoes of the genus Anopheles. Transmission is a complex phenomenon involving biological and environmental factors of humans, parasites and mosquitoes. Among more than 500 anopheline species, only a few species from different branches of the mosquito evolutionary tree transmit malaria, suggesting that their vectorial capacity has evolved independently. Anopheles albimanus (subgenus Nyssorhynchus) is an important malaria vector in the Americas. The divergence time between Anopheles gambiae, the main malaria vector in Africa, and the Neotropical vectors has been estimated to be 100 My. To better understand the biological basis of malaria transmission and to develop novel and effective means of vector control, there is a need to explore the mosquito biology beyond the An. gambiae complex. We sequenced the transcriptome of the An. albimanus adult female. By combining Sanger, 454 and Illumina sequences from cDNA libraries derived from the midgut, cuticular fat body, dorsal vessel, salivary gland and whole body, we generated a single, high-quality assembly containing 16,669 transcripts, 92% of which mapped to the An. darlingi genome and covered 90% of the core eukaryotic genome. Bidirectional comparisons between the An. gambiae, An. darlingi and An. albimanus predicted proteomes allowed the identification of 3,772 putative orthologs. More than half of the transcripts had a match to proteins in other insect vectors and had an InterPro annotation. We identified several protein families that may be relevant to the study of Plasmodium-mosquito interaction. An open source transcript annotation browser called GDAV (Genome-Delinked Annotation Viewer) was developed to facilitate public access to the data generated by this and future transcriptome projects. We have explored the adult female transcriptome of one important New World malaria vector, An. albimanus. We identified protein-coding transcripts involved in biological processes that may

Climate-based models for West Nile Culex mosquito vectors in the Northeastern US

NASA Astrophysics Data System (ADS)

Gong, Hongfei; Degaetano, Arthur T.; Harrington, Laura C.

2011-05-01

Climate-based models simulating Culex mosquito population abundance in the Northeastern US were developed. Two West Nile vector species, Culex pipiens and Culex restuans, were included in model simulations. The model was optimized by a parameter-space search within biological bounds. Mosquito population dynamics were driven by major environmental factors including temperature, rainfall, evaporation rate and photoperiod. The results show a strong correlation between the timing of early population increases (as early warning of West Nile virus risk) and decreases in late summer. Simulated abundance was highly correlated with actual mosquito capture in New Jersey light traps and validated with field data. This climate-based model simulates the population dynamics of both the adult and immature mosquito life stage of Culex arbovirus vectors in the Northeastern US. It is expected to have direct and practical application for mosquito control and West Nile prevention programs.

Mosquito population dynamics from cellular automata-based simulation

NASA Astrophysics Data System (ADS)

Syafarina, Inna; Sadikin, Rifki; Nuraini, Nuning

2016-02-01

In this paper we present an innovative model for simulating mosquito-vector population dynamics. The simulation consist of two stages: demography and dispersal dynamics. For demography simulation, we follow the existing model for modeling a mosquito life cycles. Moreover, we use cellular automata-based model for simulating dispersal of the vector. In simulation, each individual vector is able to move to other grid based on a random walk. Our model is also capable to represent immunity factor for each grid. We simulate the model to evaluate its correctness. Based on the simulations, we can conclude that our model is correct. However, our model need to be improved to find a realistic parameters to match real data.

Comparative evaluation of the efficiency of the BG-Sentinel trap, CDC light trap and Mosquito-oviposition trap for the surveillance of vector mosquitoes.

PubMed

Li, Yiji; Su, Xinghua; Zhou, Guofa; Zhang, Hong; Puthiyakunnon, Santhosh; Shuai, Shufen; Cai, Songwu; Gu, Jinbao; Zhou, Xiaohong; Yan, Guiyun; Chen, Xiao-Guang

2016-08-12

The surveillance of vector mosquitoes is important for the control of mosquito-borne diseases. To identify a suitable surveillance tool for the adult dengue vector Aedes albopictus, the efficacy of the BG-Sentinel trap, CDC light trap and Mosquito-oviposition trap (MOT) on the capture of vector mosquitoes were comparatively evaluated in this study. The capture efficiencies of the BG-Sentinel trap, CDC light trap and Mosquito-oviposition trap for common vector mosquitoes were tested in a laboratory setting, through the release-recapture method, and at two field sites of Guangzhou, China from June 2013 to May 2014. The captured mosquitoes were counted, species identified and compared among the three traps on the basis of species. In the release-recapture experiments in a laboratory setting, the BG-Sentinel trap caught significantly more Aedes albopictus and Culex quinquefasciatus than the CDC light trap and Mosquito-ovitrap, except for Anopheles sinensis. The BG-Sentinel trap had a higher efficacy in capturing female rather than male Ae. albopictus and Cx. quinquefasciatus, but the capture in CDC light traps displayed no significant differences. In the field trial, BG-Sentinel traps collected more Aedes albopictus than CDC light traps and MOTs collected in both urban and suburban areas. The BG-Sentinel trap was more sensitive for monitoring the population density of Aedes albopictus than the CDC light trap and MOT during the peak months of the year 2013. However, on an average, CDC light traps captured significantly more Cx. quinquefasciatus than BG-Sentinel traps. The population dynamics of Cx. quinquefasciatus displayed a significant seasonal variation, with the lowest numbers in the middle of the year. This study indicates that the BG-Sentinel trap is more effective than the commonly used CDC light trap and MOT in sampling adult Aedes albopictus and Culex quinquefasciatus. We recommend its use in the surveillance of dengue vector mosquitoes in China.

Diel activity patterns of major species of adult mosquitoes and ULV spraying impacts in St. John's County, Florida

USDA-ARS?s Scientific Manuscript database

Knowledge of daily activity patterns in adult mosquitoes can be used to determine the best time to apply adulticides for mosquito control. Many factors influence these activity patterns, including migration, hormonal cycles in the mosquito, hunger, and the need to lay eggs. In this study, FL scien...

Mosquitoes of the Caatinga: 1. Adults stage survey and the emerge of seven news species endemic of a dry tropical forest in Brazil.

PubMed

Marteis, Letícia Silva; Natal, Delsio; Sallum, Maria Anice Mureb; Medeiros-Sousa, Antônio Ralph; Oliveira, Tatiane Marques Porangaba; La Corte, Roseli

2017-02-01

The Caatinga is the least known Brazilian biome in terms of the diversity of Culicidae. No systematic study of the diversity or ecology of the mosquitoes of this biome is available, despite the importance of vector diseases in Brazil. The present study addressed the mosquito biodiversity in the Caatinga biome by sampling adult populations. Specimens were sampled monthly from March 2013 to September 2014 in a Caatinga conservation unit located in the Brazilian semiarid zone. Mosquito collections were carried out in Shannon traps from late afternoon to early evening, and manual aspiration was used to capture diurnal species as well. A total of 4,692 mosquitoes were collected. The most dominant and constant species were all undescribed species belonging to the genera Wyeomyia and Runchomyia, which together represented 80% of the specimens. The most abundant species of epidemiological importance was Haemagogus (Con.) leucocelaenus. The abundance of mosquitoes was positively associated with the relative humidity and temperature recorded during the month preceding the collection date. In the Caatinga, the diversity of adult mosquitoes was associated with the availability (quantity and diversity) of natural larval habitats found in the different phytophysiognomies of the biome, which vary according to temperature and humidity. The number of species unknown to science reflects the levels of endemism that exist in the study area, and reinforces the need to further taxonomic investigation in the biome. Copyright © 2016 Elsevier B.V. All rights reserved.

Mosquito Larvae in Tires from Mississippi, United States: The Efficacy of Abiotic and Biotic Parameters in Predicting Spatial and Temporal Patterns of Mosquito Populations and Communities.

PubMed

Yee, Donald A; Abuzeineh, Alisa A; Ezeakacha, Nnaemeka F; Schelble, Stephanie S; Glasgow, William C; Flanagan, Stephen D; Skiff, Jeffrey J; Reeves, Ashton; Kuehn, Kevin

2015-05-01

Container systems, including discarded vehicle tires, which support populations of mosquitoes, have been of interest for understanding the variables that produce biting adults that serve as both nuisances and as public health threats. We sampled tires in six sites at three times in 2012 across the state of Mississippi to understand the biotic and abiotic variables responsible for explaining patterns of larvae of common species, species richness, and total abundance of mosquitoes. From 498 tires sampled, we collected >58,000 immatures representing 16 species, with the most common species including Aedes albopictus (Skuse), Culex quinquefasciatus (L.), Orthopodomyia signifera (Coquillett), Aedes triseriatus (Say), Toxorhynchites rutilus septentrionalis (Coquillett), and Culex territans (Walker) accounting for ∼97% of all larvae. We also documented 32 new county records for resident species and recent arrivals in the state, including Aedes japonicus japonicus (Theobald) and Culex coronator (Dyar & Knab). Cluster analysis, which was used to associate sites and time periods based on similar mosquito composition, did reveal patterns across the state; however, there also were more general patterns between species and genera and environmental factors. Broadly, Aedes was often associated with factors related to detritus, whereas Culex was frequently associated with habitat variables (e.g., tire size and water volume) and microorganisms. Some Culex did lack factors connecting variation in early and late instars, suggesting differences between environmental determinants of oviposition and survival. General patterns between the tire environment and mosquito larvae do appear to exist, especially at the generic level, and point to inherent differences between genera that may aid in predicting vector locations and populations. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please

Mosquito-disseminated pyriproxyfen yields high breeding-site coverage and boosts juvenile mosquito mortality at the neighborhood scale.

PubMed

Abad-Franch, Fernando; Zamora-Perea, Elvira; Ferraz, Gonçalo; Padilla-Torres, Samael D; Luz, Sérgio L B

2015-04-01

Mosquito-borne pathogens pose major public health challenges worldwide. With vaccines or effective drugs still unavailable for most such pathogens, disease prevention heavily relies on vector control. To date, however, mosquito control has proven difficult, with low breeding-site coverage during control campaigns identified as a major drawback. A novel tactic exploits the egg-laying behavior of mosquitoes to have them disseminate tiny particles of a potent larvicide, pyriproxyfen (PPF), from resting to breeding sites, thus improving coverage. This approach has yielded promising results at small spatial scales, but its wider applicability remains unclear. We conducted a four-month trial within a 20-month study to investigate mosquito-driven dissemination of PPF dust-particles from 100 'dissemination stations' (DSs) deployed in a 7-ha sub-area to surveillance dwellings and sentinel breeding sites (SBSs) distributed over an urban neighborhood of about 50 ha. We assessed the impact of the trial by measuring juvenile mosquito mortality and adult mosquito emergence in each SBS-month. Using data from 1,075 dwelling-months, 2,988 SBS-months, and 29,922 individual mosquitoes, we show that mosquito-disseminated PPF yielded high coverage of dwellings (up to 100%) and SBSs (up to 94.3%). Juvenile mosquito mortality in SBSs (about 4% at baseline) increased by over one order of magnitude during PPF dissemination (about 75%). This led to a >10-fold decrease of adult mosquito emergence from SBSs, from approximately 1,000-3,000 adults/month before to about 100 adults/month during PPF dissemination. By expanding breeding-site coverage and boosting juvenile mosquito mortality, a strategy based on mosquito-disseminated PPF has potential to substantially enhance mosquito control. Sharp declines in adult mosquito emergence can lower vector/host ratios, reducing the risk of disease outbreaks. This approach is a very promising complement to current and novel mosquito control strategies

Mosquito-Disseminated Pyriproxyfen Yields High Breeding-Site Coverage and Boosts Juvenile Mosquito Mortality at the Neighborhood Scale

PubMed Central

Abad-Franch, Fernando; Zamora-Perea, Elvira; Ferraz, Gonçalo; Padilla-Torres, Samael D.; Luz, Sérgio L. B.

2015-01-01

Background Mosquito-borne pathogens pose major public health challenges worldwide. With vaccines or effective drugs still unavailable for most such pathogens, disease prevention heavily relies on vector control. To date, however, mosquito control has proven difficult, with low breeding-site coverage during control campaigns identified as a major drawback. A novel tactic exploits the egg-laying behavior of mosquitoes to have them disseminate tiny particles of a potent larvicide, pyriproxyfen (PPF), from resting to breeding sites, thus improving coverage. This approach has yielded promising results at small spatial scales, but its wider applicability remains unclear. Methodology/Principal Findings We conducted a four-month trial within a 20-month study to investigate mosquito-driven dissemination of PPF dust-particles from 100 ‘dissemination stations’ (DSs) deployed in a 7-ha sub-area to surveillance dwellings and sentinel breeding sites (SBSs) distributed over an urban neighborhood of about 50 ha. We assessed the impact of the trial by measuring juvenile mosquito mortality and adult mosquito emergence in each SBS-month. Using data from 1,075 dwelling-months, 2,988 SBS-months, and 29,922 individual mosquitoes, we show that mosquito-disseminated PPF yielded high coverage of dwellings (up to 100%) and SBSs (up to 94.3%). Juvenile mosquito mortality in SBSs (about 4% at baseline) increased by over one order of magnitude during PPF dissemination (about 75%). This led to a >10-fold decrease of adult mosquito emergence from SBSs, from approximately 1,000–3,000 adults/month before to about 100 adults/month during PPF dissemination. Conclusions/Significance By expanding breeding-site coverage and boosting juvenile mosquito mortality, a strategy based on mosquito-disseminated PPF has potential to substantially enhance mosquito control. Sharp declines in adult mosquito emergence can lower vector/host ratios, reducing the risk of disease outbreaks. This approach is a very

Modelling the impact of vector control interventions on Anopheles gambiae population dynamics

PubMed Central

2011-01-01

Background Intensive anti-malaria campaigns targeting the Anopheles population have demonstrated substantial reductions in adult mosquito density. Understanding the population dynamics of Anopheles mosquitoes throughout their whole lifecycle is important to assess the likely impact of vector control interventions alone and in combination as well as to aid the design of novel interventions. Methods An ecological model of Anopheles gambiae sensu lato populations incorporating a rainfall-dependent carrying capacity and density-dependent regulation of mosquito larvae in breeding sites is developed. The model is fitted to adult mosquito catch and rainfall data from 8 villages in the Garki District of Nigeria (the 'Garki Project') using Bayesian Markov Chain Monte Carlo methods and prior estimates of parameters derived from the literature. The model is used to compare the impact of vector control interventions directed against adult mosquito stages - long-lasting insecticide treated nets (LLIN), indoor residual spraying (IRS) - and directed against aquatic mosquito stages, alone and in combination on adult mosquito density. Results A model in which density-dependent regulation occurs in the larval stages via a linear association between larval density and larval death rates provided a good fit to seasonal adult mosquito catches. The effective mosquito reproduction number in the presence of density-dependent regulation is dependent on seasonal rainfall patterns and peaks at the start of the rainy season. In addition to killing adult mosquitoes during the extrinsic incubation period, LLINs and IRS also result in less eggs being oviposited in breeding sites leading to further reductions in adult mosquito density. Combining interventions such as the application of larvicidal or pupacidal agents that target the aquatic stages of the mosquito lifecycle with LLINs or IRS can lead to substantial reductions in adult mosquito density. Conclusions Density-dependent regulation of

Vertical Transmission of Zika Virus by Aedes aegypti and Ae. albopictus Mosquitoes.

PubMed

Ciota, Alexander T; Bialosuknia, Sean M; Ehrbar, Dylan J; Kramer, Laura D

2017-05-01

To determine the potential role of vertical transmission in Zika virus expansion, we evaluated larval pools of perorally infected Aedes aegypti and Ae. albopictus adult female mosquitoes; ≈1/84 larvae tested were Zika virus-positive; and rates varied among mosquito populations. Thus, vertical transmission may play a role in Zika virus spread and maintenance.

Exploring Mosquito Fauna of Majuro Atoll (Republic of Marshall Islands) in the Context of Zika Outbreak.

PubMed

Marie, Jérôme; Perera, Devika; Garstang, Helentina; Bossin, Herve C; Bourtzis, Kostas

2018-04-09

First autochthonous Zika clinical case was reported in the Republic of Marshall Islands (RMI) on Majuro Atoll in February 2016. An entomological survey of mosquito larvae and adult populations was carried out in four areas of Majuro, the most populated atoll of RMI encompassing different habitats (forest, rural, or urban) including some with confirmed clinical Zika cases to evaluate which mosquito species could be involved in the Zika transmission. A total of 2,367 immature and adult mosquito specimens were collected and identified to the species level. In total, five mosquito species were detected, Aedes aegypti (Linnaeus), Aedes albopictus (Skuse), Aedes marshallensis (Stone and Bohart), Culex quinquefasciatus (Say), and Culex annulirostris (Skuse) (Diptera: Culicidae), a first record for RMI. The most abundant species was Ae. aegypti presumed to be the main vector of Zika virus followed by Ae. albopictus. Improved management of breeding containers through better public awareness and community engagement, mosquito surveillance and innovative mosquito control strategies using the sterile insect technique (SIT) and/or the incompatible insect technique (IIT) could help prevent outbreaks of arboviruses in the RMI.

Convergence between a mosquito-eating predator's natural diet and its prey-choice behaviour

PubMed Central

Jackson, Robert R.; Deng, Chan

2016-01-01

On the basis of 1115 records of Evarcha culicivora feeding in the field, we can characterize this East African jumping spider (Salticidae) as being distinctively stenophagic. We can also, on the basis of laboratory prey-choice experiments, characterize E. culicivora as having a specialized prey-classification system and a hierarchy of innate preferences for various categories of mosquitoes and other arthropods. Prey from the field belonged to 10 arthropod orders, but 94.5% of the prey records were dipterans. Mosquitoes were the dominant prey (80.2% of the records), with the majority (82.9%) of the mosquitoes being females, and thereafter midges were the most common prey (9.2% of the records). Preference profiles that were determined from experiments showed strong convergence with natural diet in some, but not all, instances. In experiments, E. culicivora adults appeared to distinguish between six prey categories and juveniles between seven, with blood-carrying anopheline female mosquitoes being ranked highest in preference. For adults, this was followed by blood-carrying culicine female mosquitoes and then anopheline female mosquitoes not carrying blood, but these two preferences were reversed for juveniles. Moreover, for juveniles, but not for adults, anopheline male mosquitoes seem to be a distinct prey category ranked in preference after blood-carrying culicine females and, for both adults and juveniles, preference for midges is evident when the alternatives are not mosquitoes. These findings illustrate the importance of going beyond simply specifying preferred prey categories when characterizing predators as ‘specialized’ and a need to make clear conceptual distinctions between a predator's natural diet, the prey categories that are relevant to the predator, and the predator's prey-choicebehaviour. PMID:28083103

Rodent malaria-resistant strains of the mosquito, Anopheles gambiae, have slower population growth than -susceptible strains

PubMed Central

Voordouw, Maarten J; Anholt, Bradley R; Taylor, Pam J; Hurd, Hilary

2009-01-01

Background Trade-offs between anti-parasite defence mechanisms and other life history traits limit the evolution of host resistance to parasites and have important implications for understanding diseases such as malaria. Mosquitoes have not evolved complete resistance to malaria parasites and one hypothesis is that anti-malaria defence mechanisms are costly. Results We used matrix population models to compare the population growth rates among lines of Anopheles gambiae that had been selected for resistance or high susceptibility to the rodent malaria parasite, Plasmodium yoelii nigeriensis. The population growth rate of the resistant line was significantly lower than that of the highly susceptible and the unselected control lines, regardless of whether mosquitoes were infected with Plasmodium or not. The lower population growth of malaria-resistant mosquitoes was caused by reduced post blood-feeding survival of females and poor egg hatching. Conclusion With respect to eradicating malaria, the strategy of releasing Plasmodium-resistant Anopheles mosquitoes is unlikely to be successful if the costs of Plasmodium-resistance in the field are as great as the ones measured in this study. High densities of malaria-resistant mosquitoes would have to be maintained by continuous release from captive breeding facilities. PMID:19379508

Established Population of the Invasive Mosquito Species Aedes albopictus in Romania, 2012-14.

PubMed

Prioteasa, Liviu F; Dinu, Sorin; Fălcuţă, Elena; Ceianu, Cornelia S

2015-06-01

During an entomological investigation carried out in Bucharest and surroundings in fall of 2012, 45 adult mosquitoes (38 females and 7 males) of Aedes albopictus were collected in a neighborhood from the southern area of the city. The morphological identification of the species was further confirmed by sequencing 2 mitochondrial DNA markers: the cytochrome c oxidase subunit I and NADH dehydrogenase subunit 5 genes. Aedes albopictus was collected again in 2013 in the same area from July until October. During late summer the species was found also in another location in the city, downtown Bucharest. Larvae were found in water barrels and other types of household containers, as well as in rain catch basins. In 2014, following a nuisance complaint of a Bucharest inhabitant, the entomological investigation found aggressive Ae. albopictus adults on his property that harbored many mosquito larvae in container-type breeding habitats. These findings are the 1st records of this invasive species and of its breeding population in Romania, and show maintenance of the species over 2 winter seasons. Surveillance of the species outside the area of the capital city was not performed, therefore it is not known whether Ae. albopictus has been introduced in other regions of the country. The presence of Ae. albopictus has been reported every year (2012-14) to competent public health authorities, stressing on the importance of surveillance and of implementation of control measures.

Incorporating the effects of humidity in a mechanistic model of Anopheles gambiae mosquito population dynamics in the Sahel region of Africa

PubMed Central

2013-01-01

Background Low levels of relative humidity are known to decrease the lifespan of mosquitoes. However, most current models of malaria transmission do not account for the effects of relative humidity on mosquito survival. In the Sahel, where relative humidity drops to levels <20% for several months of the year, we expect relative humidity to play a significant role in shaping the seasonal profile of mosquito populations. Here, we present a new formulation for Anopheles gambiae sensu lato (s.l.) mosquito survival as a function of temperature and relative humidity and investigate the effect of humidity on simulated mosquito populations. Methods Using existing observations on relationships between temperature, relative humidity and mosquito longevity, we developed a new equation for mosquito survival as a function of temperature and relative humidity. We collected simultaneous field observations on temperature, wind, relative humidity, and anopheline mosquito populations for two villages from the Sahel region of Africa, which are presented in this paper. We apply this equation to the environmental data and conduct numerical simulations of mosquito populations using the Hydrology, Entomology and Malaria Transmission Simulator (HYDREMATS). Results Relative humidity drops to levels that are uncomfortable for mosquitoes at the end of the rainy season. In one village, Banizoumbou, water pools dried up and interrupted mosquito breeding shortly after the end of the rainy season. In this case, relative humidity had little effect on the mosquito population. However, in the other village, Zindarou, the relatively shallow water table led to water pools that persisted several months beyond the end of the rainy season. In this case, the decrease in mosquito survival due to relative humidity improved the model’s ability to reproduce the seasonal pattern of observed mosquito abundance. Conclusions We proposed a new equation to describe Anopheles gambiae s.l. mosquito survival as a

Biological control of mosquitoes in scrap tires in Brownsville, Texas, USA and Matamoros, Tamaulipas, Mexico.

PubMed

Uejio, Christopher K; Hayden, Mary H; Zielinski-Gutierrez, Emily; Lopez, Jose Luis Robles; Barrera, Roberto; Amador, Manuel; Thompson, Gregory; Waterman, Stephen H

2014-06-01

Dengue periodically circulates in southern Texas and neighboring Tamaulipas, Mexico; thus, a closer examination of human and vector ecology at the northern limits of North American transmission may improve prevention activities. Scrap tires produce large mosquito populations and increase the risk of dengue transmission. Some households choose not to pay tire disposal fees, and many tires are illegally dumped in residential areas. Biological control may provide low-cost and environmentally friendly mosquito control. This pilot study evaluated the ability of Mesocyclops longisetus to reduce mosquito populations in existing residential scrap tire piles. Mosquito populations were measured by the number of all mosquito pupae within tires or adult Aedes aegypti and Ae. albopictus near piles. Mesocyclops longisetus treated piles did not significantly reduce total mosquito pupae (P = 0.07) in Matamoros, Mexico. The study also evaluated the efficacy of native Toxorhynchites moctezuma which preferentially colonized tire piles under vegetation cover in Brownsville, TX. Toxorhynchites moctezuma larvae significantly reduced total mosquito pupae, but the strength of control diminished over time.

Population genomics reveals that an anthropophilic population of Aedes aegypti mosquitoes in West Africa recently gave rise to American and Asian populations of this major disease vector.

PubMed

Crawford, Jacob E; Alves, Joel M; Palmer, William J; Day, Jonathan P; Sylla, Massamba; Ramasamy, Ranjan; Surendran, Sinnathamby N; Black, William C; Pain, Arnab; Jiggins, Francis M

2017-02-28

The mosquito Aedes aegypti is the main vector of dengue, Zika, chikungunya and yellow fever viruses. This major disease vector is thought to have arisen when the African subspecies Ae. aegypti formosus evolved from being zoophilic and living in forest habitats into a form that specialises on humans and resides near human population centres. The resulting domestic subspecies, Ae. aegypti aegypti, is found throughout the tropics and largely blood-feeds on humans. To understand this transition, we have sequenced the exomes of mosquitoes collected from five populations from around the world. We found that Ae. aegypti specimens from an urban population in Senegal in West Africa were more closely related to populations in Mexico and Sri Lanka than they were to a nearby forest population. We estimate that the populations in Senegal and Mexico split just a few hundred years ago, and we found no evidence of Ae. aegypti aegypti mosquitoes migrating back to Africa from elsewhere in the tropics. The out-of-Africa migration was accompanied by a dramatic reduction in effective population size, resulting in a loss of genetic diversity and rare genetic variants. We conclude that a domestic population of Ae. aegypti in Senegal and domestic populations on other continents are more closely related to each other than to other African populations. This suggests that an ancestral population of Ae. aegypti evolved to become a human specialist in Africa, giving rise to the subspecies Ae. aegypti aegypti. The descendants of this population are still found in West Africa today, and the rest of the world was colonised when mosquitoes from this population migrated out of Africa. This is the first report of an African population of Ae. aegypti aegypti mosquitoes that is closely related to Asian and American populations. As the two subspecies differ in their ability to vector disease, their existence side by side in West Africa may have important implications for disease transmission.

Characteristics of Aedes aegypti adult mosquitoes in rural and urban areas of western and coastal Kenya

PubMed Central

Ndenga, Bryson Alberto; Mutuku, Francis Maluki; Ngugi, Harun Njenga; Mbakaya, Joel Omari; Aswani, Peter; Musunzaji, Peter Siema; Vulule, John; Mukoko, Dunstan; Kitron, Uriel; LaBeaud, Angelle Desiree

2017-01-01

Aedes aegypti is the main vector for yellow fever, dengue, chikungunya and Zika viruses. Recent outbreaks of dengue and chikungunya have been reported in Kenya. Presence and abundance of this vector is associated with the risk for the occurrence and transmission of these diseases. This study aimed to characterize the presence and abundance of Ae. aegypti adult mosquitoes from rural and urban sites in western and coastal regions of Kenya. Presence and abundance of Ae. aegypti adult mosquitoes were determined indoors and outdoors in two western (urban Kisumu and rural Chulaimbo) and two coastal (urban Ukunda and rural Msambweni) sites in Kenya. Sampling was performed using quarterly human landing catches, monthly Prokopack automated aspirators and monthly Biogents-sentinel traps. A total of 2,229 adult Ae. aegypti mosquitoes were collected: 785 (35.2%) by human landing catches, 459 (20.6%) by Prokopack aspiration and 985 (44.2%) by Biogents-sentinel traps. About three times as many Ae. aegypti mosquitoes were collected in urban than rural sites (1,650 versus 579). Comparable numbers were collected in western (1,196) and coastal (1,033) sites. Over 80% were collected outdoors through human landing catches and Prokopack aspiration. The probability of collecting Ae. aegypti mosquitoes by human landing catches was significantly higher in the afternoon than morning hours (P<0.001), outdoors than indoors (P<0.001) and in urban than rural sites (P = 0.008). Significantly more Ae. aegypti mosquitoes were collected using Prokopack aspiration outdoors than indoors (P<0.001) and in urban than rural areas (P<0.001). Significantly more mosquitoes were collected using Biogents-sentinel traps in urban than rural areas (P = 0.008) and in western than coastal sites (P = 0.006). The probability of exposure to Ae. aegypti bites was highest in urban areas, outdoors and in the afternoon hours. These characteristics have major implications for the possible transmission of arboviral

Characteristics of Aedes aegypti adult mosquitoes in rural and urban areas of western and coastal Kenya.

PubMed

Ndenga, Bryson Alberto; Mutuku, Francis Maluki; Ngugi, Harun Njenga; Mbakaya, Joel Omari; Aswani, Peter; Musunzaji, Peter Siema; Vulule, John; Mukoko, Dunstan; Kitron, Uriel; LaBeaud, Angelle Desiree

2017-01-01

Aedes aegypti is the main vector for yellow fever, dengue, chikungunya and Zika viruses. Recent outbreaks of dengue and chikungunya have been reported in Kenya. Presence and abundance of this vector is associated with the risk for the occurrence and transmission of these diseases. This study aimed to characterize the presence and abundance of Ae. aegypti adult mosquitoes from rural and urban sites in western and coastal regions of Kenya. Presence and abundance of Ae. aegypti adult mosquitoes were determined indoors and outdoors in two western (urban Kisumu and rural Chulaimbo) and two coastal (urban Ukunda and rural Msambweni) sites in Kenya. Sampling was performed using quarterly human landing catches, monthly Prokopack automated aspirators and monthly Biogents-sentinel traps. A total of 2,229 adult Ae. aegypti mosquitoes were collected: 785 (35.2%) by human landing catches, 459 (20.6%) by Prokopack aspiration and 985 (44.2%) by Biogents-sentinel traps. About three times as many Ae. aegypti mosquitoes were collected in urban than rural sites (1,650 versus 579). Comparable numbers were collected in western (1,196) and coastal (1,033) sites. Over 80% were collected outdoors through human landing catches and Prokopack aspiration. The probability of collecting Ae. aegypti mosquitoes by human landing catches was significantly higher in the afternoon than morning hours (P<0.001), outdoors than indoors (P<0.001) and in urban than rural sites (P = 0.008). Significantly more Ae. aegypti mosquitoes were collected using Prokopack aspiration outdoors than indoors (P<0.001) and in urban than rural areas (P<0.001). Significantly more mosquitoes were collected using Biogents-sentinel traps in urban than rural areas (P = 0.008) and in western than coastal sites (P = 0.006). The probability of exposure to Ae. aegypti bites was highest in urban areas, outdoors and in the afternoon hours. These characteristics have major implications for the possible transmission of arboviral

Application of biogenic carbon dioxide produced by yeast with different carbon sources for attraction of mosquitoes towards adult mosquito traps.

PubMed

Sukumaran, D; Ponmariappan, S; Sharma, Atul K; Jha, Hemendra K; Wasu, Yogesh H; Sharma, Ajay K

2016-04-01

Surveillance is a prime requisite for controlling arthropod vectors like mosquitoes that transmit diseases such as malaria, dengue and chikungunya. Carbon dioxide (CO2) is one of the main cues from vertebrate breath that attracts mosquitoes towards the host. Hence, CO2 is used as an attractant during surveillance of mosquitoes either from commercial cylinders or dry ice for mosquito traps. In the present study, the biogenic carbon dioxide production was optimized with different carbon sources such as glucose, simple sugar and jaggery with and without yeast peptone dextrose (YPD) media using commercial baker's yeast. The results showed that yeast produced more biogenic CO2 with simple sugar as compared to other carbon sources. Further substrate concentration was optimized for the continuous production of biogenic CO2 for a minimum of 12 h by using 10 g of baker's yeast with 50 g of simple sugar added to 1.5 l distilled water (without YPD media) in a 2-l plastic bottle. This setup was applied in field condition along with two different mosquito traps namely Mosquito Killing System (MKS) and Biogents Sentinel (BGS) trap. Biogenic CO2 from this setup has increased the trapping efficiency of MKS by 6.48-fold for Culex quinquefasciatus, 2.62-fold for Aedes albopictus and 1.5-fold for Anopheles stephensi. In the case of BGS, the efficiency was found to be increased by 3.54-fold for Ae. albopictus, 4.33-fold for An. stephensi and 1.3-fold for Armigeres subalbatus mosquitoes. On the whole, plastic bottle setup releasing biogenic CO2 from sugar and yeast has increased the efficiency of MKS traps by 6.38-fold and 2.74-fold for BGS traps as compared to traps without biogenic CO2. The present study reveals that, among different carbon sources used, simple sugar as a substance (which is economical and readily available across the world) yielded maximum biogenic CO2 with yeast. This setup can be used as an alternative to CO2 cylinder and dry ice in any adult mosquito traps to

AN IMPROVED TRAP TO CAPTURE ADULT CONTAINER-INHABITING MOSQUITOES

PubMed Central

BARRERA, ROBERTO; MACKAY, ANDREW J.; AMADOR, MANUEL

2015-01-01

Although dengue viruses are thought to be transmitted by Aedes aegypti in Puerto Rico, Aedes mediovittatus, the Caribbean tree hole mosquito, is also a potential vector. This species is native to the Greater Antilles and has been shown to be a competent vector of dengue viruses in the laboratory. Consequently, it has been suggested that Ae. mediovittatus could be acting as a secondary vector or virus reservoir. This study was part of an ongoing investigation into this, and it aimed to determine whether BG-Sentinel traps (BGS traps) could be used to collect adults of this mosquito and could be modified to increase the number of captures of this species in the field. We conducted experiments to test the relative attractiveness of BGS traps to Ae. mediovittatus and Ae. aegypti and explored the effects of chemical lures (BG-Lure, CO2, octenol) and optical properties (color, size) on the capture rates of BGS traps in a large, outdoor cage in San Juan city, Puerto Rico. We also conducted field tests to compare modified BGS traps with the original traps in a rural community in Patillas municipality, Puerto Rico. Results obtained from the large, outdoor cage experiments indicated that trap captures of both mosquito species could be significantly enhanced by using black instead of white BGS traps combined with BG-Lure. Field experiments revealed that the modified traps captured a significantly greater number of Ae. aegypti, Ae. mediovittatus, and Culex quinquefasciatus, with greater sensitivity for the latter 2 species, and also captured a larger number of mosquito species and a smaller ratio of Ae. aegypti to Ae. mediovittatus, with greater than expected species co-occurrences. PMID:24551969

HIV/AIDS Misconceptions among Latinos: Findings from a Population-Based Survey of California Adults

ERIC Educational Resources Information Center

Ritieni, Assunta; Moskowitz, Joel; Tholandi, Maya

2008-01-01

Misconceptions about HIV/AIDS among Latino adults (N=454) in California were examined using data from a population-based telephone survey conducted in 2000. Common misconceptions concerning modes of HIV transmission included transmission via mosquito or animal bite (64.1%), public facilities (48.3%), or kissing someone on the cheek (24.8%). A…

Permethrin treated clothing to protect outdoor workers: evaluation of different methods for mosquito exposure against populations with differing resistance status.

PubMed

Richards, Stephanie L; Agada, Nwanne; Balanay, Jo Anne G; White, Avian V

2018-02-01

Minimizing arthropod exposure (e.g. mosquito and tick bites) is vital to protect health of outdoor workers. Personal protective measures can help protect against exposure. Here, the quantity of permethrin was evaluated for different fabric types after washing. Cone and petri dish exposure assays were used to investigate the knockdown/mortality of permethrin-susceptible and permethrin-resistant populations of mosquitoes. Permethrin-treated clothing was effective against the tested mosquito population that was susceptible to permethrin but not a permethrin-resistant population. Permethrin quantity was significantly highest in the 100% cotton fabric and for the 0 wash group. Permethrin quantity in fabrics decreased with washing. No significant differences (p > 0.05) were observed in knockdown/mortality rates for either exposure method. The protective effect of permethrin-treated clothing against mosquitoes is impacted by many factors, e.g. wash frequency, fabric type, and the susceptibility/resistance status of local mosquito populations.

Dengue in Java, Indonesia: Relevance of Mosquito Indices as Risk Predictors

PubMed Central

Wijayanti, Siwi P. M.; Sunaryo, Sunaryo; Suprihatin, Suprihatin; McFarlane, Melanie; Rainey, Stephanie M.; Dietrich, Isabelle; Schnettler, Esther; Biek, Roman; Kohl, Alain

2016-01-01

Background No vaccine is currently available for dengue virus (DENV), therefore control programmes usually focus on managing mosquito vector populations. Entomological surveys provide the most common means of characterising vector populations and predicting the risk of local dengue virus transmission. Despite Indonesia being a country strongly affected by DENV, only limited information is available on the local factors affecting DENV transmission and the suitability of available survey methods for assessing risk. Methodology/principal findings We conducted entomological surveys in the Banyumas Regency (Central Java) where dengue cases occur on an annual basis. Four villages were sampled during the dry and rainy seasons: two villages where dengue was endemic, one where dengue cases occurred sporadically and one which was dengue-free. In addition to data for conventional larvae indices, we collected data on pupae indices, and collected adult mosquitoes for species identification in order to determine mosquito species composition and population density. Traditionally used larval indices (House indices, Container indices and Breteau indices) were found to be inadequate as indicators for DENV transmission risk. In contrast, species composition of adult mosquitoes revealed that competent vector species were dominant in dengue endemic and sporadic villages. Conclusions/significance Our data suggested that the utility of traditional larvae indices, which continue to be used in many dengue endemic countries, should be re-evaluated locally. The results highlight the need for validation of risk indicators and control strategies across DENV affected areas here and perhaps elsewhere in SE Asia. PMID:26967524

Dengue in Java, Indonesia: Relevance of Mosquito Indices as Risk Predictors.

PubMed

Wijayanti, Siwi P M; Sunaryo, Sunaryo; Suprihatin, Suprihatin; McFarlane, Melanie; Rainey, Stephanie M; Dietrich, Isabelle; Schnettler, Esther; Biek, Roman; Kohl, Alain

2016-03-01

No vaccine is currently available for dengue virus (DENV), therefore control programmes usually focus on managing mosquito vector populations. Entomological surveys provide the most common means of characterising vector populations and predicting the risk of local dengue virus transmission. Despite Indonesia being a country strongly affected by DENV, only limited information is available on the local factors affecting DENV transmission and the suitability of available survey methods for assessing risk. We conducted entomological surveys in the Banyumas Regency (Central Java) where dengue cases occur on an annual basis. Four villages were sampled during the dry and rainy seasons: two villages where dengue was endemic, one where dengue cases occurred sporadically and one which was dengue-free. In addition to data for conventional larvae indices, we collected data on pupae indices, and collected adult mosquitoes for species identification in order to determine mosquito species composition and population density. Traditionally used larval indices (House indices, Container indices and Breteau indices) were found to be inadequate as indicators for DENV transmission risk. In contrast, species composition of adult mosquitoes revealed that competent vector species were dominant in dengue endemic and sporadic villages. Our data suggested that the utility of traditional larvae indices, which continue to be used in many dengue endemic countries, should be re-evaluated locally. The results highlight the need for validation of risk indicators and control strategies across DENV affected areas here and perhaps elsewhere in SE Asia.

Modelling Wolbachia infection in a sex-structured mosquito population carrying West Nile virus.

PubMed

Farkas, József Z; Gourley, Stephen A; Liu, Rongsong; Yakubu, Abdul-Aziz

2017-09-01

Wolbachia is possibly the most studied reproductive parasite of arthropod species. It appears to be a promising candidate for biocontrol of some mosquito borne diseases. We begin by developing a sex-structured model for a Wolbachia infected mosquito population. Our model incorporates the key effects of Wolbachia infection including cytoplasmic incompatibility and male killing. We also allow the possibility of reduced reproductive output, incomplete maternal transmission, and different mortality rates for uninfected/infected male/female individuals. We study the existence and local stability of equilibria, including the biologically relevant and interesting boundary equilibria. For some biologically relevant parameter regimes there may be multiple coexistence steady states including, very importantly, a coexistence steady state in which Wolbachia infected individuals dominate. We also extend the model to incorporate West Nile virus (WNv) dynamics, using an SEI modelling approach. Recent evidence suggests that a particular strain of Wolbachia infection significantly reduces WNv replication in Aedes aegypti. We model this via increased time spent in the WNv-exposed compartment for Wolbachia infected female mosquitoes. A basic reproduction number [Formula: see text] is computed for the WNv infection. Our results suggest that, if the mosquito population consists mainly of Wolbachia infected individuals, WNv eradication is likely if WNv replication in Wolbachia infected individuals is sufficiently reduced.

Distribution and phylogeny of Wolbachia strains in wild mosquito populations in Sri Lanka.

PubMed

Nugapola, N W Nalaka P; De Silva, W A Priyanka P; Karunaratne, S H P Parakrama

2017-05-10

Wolbachia are a group of maternally inherited intracellular bacteria known to be widespread among arthropods. Infections with Wolbachia cause declines of host populations, and also induce host resistance to a wide range of pathogens. Over the past few decades, researchers were curious to use Wolbachia as a biological tool to control mosquito vectors. During the present study, assessment of the prevalence of Wolbachia infections among wild mosquito populations in Sri Lanka where mosquito-borne diseases are a major health concern, was carried out for the first time. DNA was extracted from the abdomens of mosquitoes, collected from seven provinces, and screened for the presence of Wolbachia by PCR using wsp and groE primers. Group-specific and strain-specific primers were used to classify Wolbachia into the supergroups A and B, and into the strains Mel, AlbA and Pip. A total of 330 individual mosquitoes belonging to 22 species and 7 genera were screened. Eighty-seven mosquitoes (26.36%) belonging to four species (i.e. Aedes albopictus, Culex quinquefasciatus, Armigeres subalbatus and Mansonia uniformis) were positive for Wolbachia infections. Primary vector of the dengue fever, Ae. aegypti was negative for Wolbachia infections while the secondary vector, Ae. albopictus, showed a very high infection rate. The filarial vector C. quinquefasciatus had a relatively high rate of infection. Japanese encephalitis vectors C. gelidus and C. triteaneorynchus, and the Anopheles vectors of malaria were negative for Wolbachia infections. Nine sequences of Wolbachia-positive PCR products were deposited in the GenBank and compared with other available data. Aedes albopictus was infected with both Wolbachia strains A (AlbA) and B (Pip) supergroups. Phylogenetic analysis of the wsp sequences showed two major branches confirming identities obtained from the PCR screening with strain-specific primers. Wolbachia infections were found only among four mosquito species in Sri Lanka: Aedes

Using barcoded Zika virus to assess virus population structure in vitro and in Aedes aegypti mosquitoes.

PubMed

Weger-Lucarelli, James; Garcia, Selene M; Rückert, Claudia; Byas, Alex; O'Connor, Shelby L; Aliota, Matthew T; Friedrich, Thomas C; O'Connor, David H; Ebel, Gregory D

2018-06-20

Arboviruses such as Zika virus (ZIKV, Flaviviridae; Flavivirus) must replicate in both mammalian and insect hosts possessing strong immune defenses. Accordingly, transmission between and replication within hosts involves genetic bottlenecks, during which viral population size and genetic diversity may be significantly reduced. To help quantify these bottlenecks and their effects, we constructed 4 "barcoded" ZIKV populations that theoretically contain thousands of barcodes each. After identifying the most diverse barcoded virus, we passaged this virus 3 times in 2 mammalian and mosquito cell lines and characterized the population using deep sequencing of the barcoded region of the genome. C6/36 maintain higher barcode diversity, even after 3 passages, than Vero. Additionally, field-caught mosquitoes exposed to the virus to assess bottlenecks in a natural host. A progressive reduction in barcode diversity occurred throughout systemic infection of these mosquitoes. Differences in bottlenecks during systemic spread were observed between different populations of Aedes aegypti. Copyright © 2018. Published by Elsevier Inc.

Effects of Mesocyclops longisetus (Copepoda:Cyclopidae) on mosquitoes that inhabit tires: influence of litter type, quality, and quantity.

PubMed

Schreiber, E T; Hallmon, C F; Eskridge, K M; Marten, G G

1996-12-01

A 59-week study was conducted to evaluate the impact of adult Mesocyclops longisetus populations on larval mosquito species inhabiting tires. Greater than 90% reduction of number of 1st and 2nd instars was recorded by 4 wk with 90% reduction of number of 3rd and 4th instars after 7 wk. Reduced control was noted with the onset of cooler winter water temperature. Overall. a 52% reduction in the number of 1st and 2nd instars was achieved, and a 57% reduction was noted in number of 3rd- and 4th-instar mosquito larvae. Cooler temperatures resulted in a decline of adult Mesocyclops, which resulted in reduced larval control. Significantly greater numbers of Mesocyclops adults were collected in tires with either new litter or heavy amounts of litter regardless of litter type. Lastly, litter type, either oak leaves or pine needles, did not influence mosquito reduction or abundance of Mesocyclops populations.

The use of sequential mark-release-recapture experiments to estimate population size, survival and dispersal of male mosquitoes of the  Anopheles gambiae complex in Bana, a west African humid savannah village.

PubMed

Epopa, Patric Stephane; Millogo, Abdoul Azize; Collins, Catherine Matilda; North, Ace; Tripet, Frederic; Benedict, Mark Quentin; Diabate, Abdoulaye

2017-08-07

Vector control is a major component of the malaria control strategy. The increasing spread of insecticide resistance has encouraged the development of new tools such as genetic control which use releases of modified male mosquitoes. The use of male mosquitoes as part of a control strategy requires an improved understanding of male mosquito biology, including the factors influencing their survival and dispersal, as well as the ability to accurately estimate the size of a target mosquito population. This study was designed to determine the seasonal variation in population size via repeated mark-release-recapture experiments and to estimate the survival and dispersal of male mosquitoes of the Anopheles gambiae complex in a small west African village. Mark-release-recapture experiments were carried out in Bana Village over two consecutive years, during the wet and the dry seasons. For each experiment, around 5000 (3407-5273) adult male Anopheles coluzzii mosquitoes were marked using three different colour dye powders (red, blue and green) and released in three different locations in the village (centre, edge and outside). Mosquitoes were recaptured at sites spread over the village for seven consecutive days following the releases. Three different capture methods were used: clay pots, pyrethroid spray catches and swarm sampling. Swarm sampling was the most productive method for recapturing male mosquitoes in the field. Population size and survival were estimated by Bayesian analyses of the Fisher-Ford model, revealing an about 10-fold increase in population size estimates between the end of dry season (10,000-50,000) to the wet season (100,000-500,000). There were no detectable seasonal effects on mosquito survival, suggesting that factors other than weather may play an important role. Mosquito dispersal ranged from 40 to 549 m over the seven days of each study and was not influenced by the season, but mainly by the release location, which explained more than 44% of

Tropical Mosquito Assemblages Demonstrate ‘Textbook’ Annual Cycles

PubMed Central

Franklin, Donald C.; Whelan, Peter I.

2009-01-01

Background Annual biological rhythms are often depicted as predictably cyclic, but quantitative evaluations are few and rarely both cyclic and constant among years. In the monsoon tropics, the intense seasonality of rainfall frequently drives fluctuations in the populations of short-lived aquatic organisms. However, it is unclear how predictably assemblage composition will fluctuate because the intensity, onset and cessation of the wet season varies greatly among years. Methodology/Principal Findings Adult mosquitoes were sampled using EVS suction traps baited with carbon dioxide around swamplands adjacent to the city of Darwin in northern Australia. Eleven sites were sampled weekly for five years, and one site weekly for 24 years, the sample of c. 1.4 million mosquitoes yielding 63 species. Mosquito abundance, species richness and diversity fluctuated seasonally, species richness being highly predictable. Ordination of assemblage composition demonstrated striking annual cycles that varied little from year to year. The mosquito assemblage was temporally structured by a succession of species peaks in abundance. Conclusion/Significance Ordination provided strong visual representation of annual rhythms in assemblage composition and the means to evaluate variability among years. Because most mosquitoes breed in shallow freshwater which fluctuates with rainfall, we did not anticipate such repeatability; we conclude that mosquito assemblage composition appears adapted to predictable elements of the rainfall. PMID:20011531

Development of an autodissemination strategy for the deployment of novel control agents targeting the common malaria mosquito, Anopheles quadrimaculatus say (Diptera: Culicidae).

PubMed

Swale, Daniel R; Li, Zhilin; Kraft, Jake Z; Healy, Kristen; Liu, Mei; David, Connie M; Liu, Zhijun; Foil, Lane D

2018-04-01

The reduced efficacy of current Anopheline mosquito control methods underscores the need to develop new methods of control that exploit unique target sites and/or utilizes novel deployment methods. Autodissemination methodologies using insect growth regulators (IGRs) is growing in interest and has been shown to be effective at controlling Aedes mosquitoes in semi-field and field environments, yet little information exists for Anopheline mosquitoes. Therefore, we tested the hypothesis that female-driven autodissemination of an IGR combined with a new mechanism of action insecticide (Kir channel inhibitor) could be employed to reduce Anopheline populations. We studied the ability of three IGRs to be transferred to the larval habitat during oviposition in laboratory and semi-field environments. Adult mosquitoes were exposed to the chemicals for 4 hours immediately after blood feeding and efficacy was tested using classical methodologies, including adult emergence inhibition and High Performance Liquid Chromatography (HPLC). A complete autodissemination design was tested in a semi-field environment. Larval survivability and adult emergence were significantly reduced in habitats that were visited by novaluron treated adults, but no statistical differences were observed with pyriproxyfen or triflumuron. These data suggested novaluron, but not pyriproxyfen or triflumuron, was horizontally transferred from the adult mosquito to the larval habitat during oviposition. HPLC studies supported the toxicity data and showed that novaluron was present in the majority of larval habitats, suggesting that novaluron can be horizontally transferred by Anopheles quadrimaculatus. Importantly, the combination of novaluron and the Kir channel inhibitor, VU041, was capable of reducing adult and larval populations in semi-field environments. Novaluron can be transferred to the adult at a greater efficacy and/or is not degraded as quickly during the gonotropic cycle when compared to

Repellent, irritant and toxic effects of 20 plant extracts on adults of the malaria vector Anopheles gambiae mosquito.

PubMed

Deletre, Emilie; Martin, Thibaud; Campagne, Pascal; Bourguet, Denis; Cadin, Andy; Menut, Chantal; Bonafos, Romain; Chandre, Fabrice

2013-01-01

Pyrethroid insecticides induce an excito-repellent effect that reduces contact between humans and mosquitoes. Insecticide use is expected to lower the risk of pathogen transmission, particularly when impregnated on long-lasting treated bednets. When applied at low doses, pyrethroids have a toxic effect, however the development of pyrethroid resistance in several mosquito species may jeopardize these beneficial effects. The need to find additional compounds, either to kill disease-carrying mosquitoes or to prevent mosquito contact with humans, therefore arises. In laboratory conditions, the effects (i.e., repellent, irritant and toxic) of 20 plant extracts, mainly essential oils, were assessed on adults of Anopheles gambiae, a primary vector of malaria. Their effects were compared to those of DEET and permethrin, used as positive controls. Most plant extracts had irritant, repellent and/or toxic effects on An. gambiae adults. The most promising extracts, i.e. those combining the three types of effects, were from Cymbopogon winterianus, Cinnamomum zeylanicum and Thymus vulgaris. The irritant, repellent and toxic effects occurred apparently independently of each other, and the behavioural response of adult An. gambiae was significantly influenced by the concentration of the plant extracts. Mechanisms underlying repellency might, therefore, differ from those underlying irritancy and toxicity. The utility of the efficient plant extracts for vector control as an alternative to pyrethroids may thus be envisaged.

Repellent, Irritant and Toxic Effects of 20 Plant Extracts on Adults of the Malaria Vector Anopheles gambiae Mosquito

PubMed Central

Deletre, Emilie; Martin, Thibaud; Campagne, Pascal; Bourguet, Denis; Cadin, Andy; Menut, Chantal; Bonafos, Romain; Chandre, Fabrice

2013-01-01

Pyrethroid insecticides induce an excito-repellent effect that reduces contact between humans and mosquitoes. Insecticide use is expected to lower the risk of pathogen transmission, particularly when impregnated on long-lasting treated bednets. When applied at low doses, pyrethroids have a toxic effect, however the development of pyrethroid resistance in several mosquito species may jeopardize these beneficial effects. The need to find additional compounds, either to kill disease-carrying mosquitoes or to prevent mosquito contact with humans, therefore arises. In laboratory conditions, the effects (i.e., repellent, irritant and toxic) of 20 plant extracts, mainly essential oils, were assessed on adults of Anopheles gambiae, a primary vector of malaria. Their effects were compared to those of DEET and permethrin, used as positive controls. Most plant extracts had irritant, repellent and/or toxic effects on An. gambiae adults. The most promising extracts, i.e. those combining the three types of effects, were from Cymbopogon winterianus, Cinnamomum zeylanicum and Thymus vulgaris. The irritant, repellent and toxic effects occurred apparently independently of each other, and the behavioural response of adult An. gambiae was significantly influenced by the concentration of the plant extracts. Mechanisms underlying repellency might, therefore, differ from those underlying irritancy and toxicity. The utility of the efficient plant extracts for vector control as an alternative to pyrethroids may thus be envisaged. PMID:24376515

Distribution of Aedes mosquitoes in the Kilimanjaro Region of northern Tanzania.

PubMed

Hertz, Julian T; Lyaruu, Lucille J; Ooi, Eng Eong; Mosha, Franklin W; Crump, John A

2016-05-01

Little is known about the presence and distribution of Aedes mosquitoes in northern Tanzania despite the occurence of viruses transmitted by these mosquitoes such as Chikungunya virus (CHIKV) and Dengue virus (DENV) in the region. Adult and larval mosquitoes were collected from rural and urban settings across a wide range of altitudes in the Kilimanjaro Region using the Mosquito Magnet CO2 Trap for collection of adults and old tires for breeding of larvae. Polymerase chain reaction assays were performed on captured adult mosquitoes to detect the presence of CHIKV and DENV. A total of 2609 Aedes aegypti adult mosquitoes were collected; no other Aedes species larvae were found. Mosquito yields were significantly higher in urban settings than rural settings (26.5 vs. 1.9 mosquitoes per day, p = 0.037). A total of 6570 Ae. aegypti larvae were collected from old tires; no other Aedes species larvae were found. Of the 2609 adult mosquitoes collected, none tested positive for CHIKV or DENV. As far as we are aware, this paper reports for the first time the presence of Ae. aegypti in the Kilimanjaro Region of northern Tanzania. Although CHIKV and DENV were not isolated from any of the collected mosquitoes in this study, the apparent absence of other Aedes species in the area suggests that Ae. aegypti is the primary local vector of these infections.

Species Composition and WNV Screening of Mosquitoes from Lagoons in a Wetland Area of the Algarve, Portugal

PubMed Central

Freitas, Ferdinando B.; Novo, Maria Teresa; Esteves, Aida; de Almeida, A. Paulo G.

2012-01-01

The aim of this study was to evaluate mosquito abundance, species diversity, larval and adult population dynamics in seven lagoons integrated in the wetland coastal system of the Algarve, Portugal, in the summer of 2007, as well as the screening of these for West Nile virus (WNV). WNV has been isolated from mosquitoes in this region, in the summer of 2004, next to the putative area of infection of two linked human WN cases. Adult mosquitoes were collected with CDC traps baited with CO2, and potential breeding sites were surveyed for immature stages. Morphological identification of 1,432 adult mosquitoes and 85 larvae revealed the presence of 10 species: Anopheles atroparvus, Anopheles algeriensis, Coquillettidia richiardii, Culex modestus, Culex pipiens, Culex theileri, Culex univittatus, Culiseta longiareolata, Aedes caspius, and Aedes detritus. Adult mosquito peak densities were recorded in July, contrasting with null larval breeding in the same month in the surveyed biotopes. Most abundant species were C. pipiens (52%), C. theileri (29%), and A. caspius (11%). Lagoon Salgados and Quinta das Salinas, exhibited the highest similarity of culicid fauna, despite being most distant from each other, Female mosquitoes (1,249 specimens) screened by RT-PCR, did not reveal WNV products. However, previous detection of WNV activity in this area, susceptible to re-introductions, demands for continued vigilance. PMID:22347862

Study of Culex tritaeniorhynchus and species composition of mosquitoes in a rice field in Greece.

PubMed

Lytra, Ioanna; Emmanouel, Nikolaos

2014-06-01

Mosquito species composition and seasonal abundance were studied in a rice field in western Greece over a three-year period (2009-2011). A total of 11,716 larvae and pupae of mosquitoes were recorded, representing seven species, namely Aedes caspius (Pallas), Anopheles hyrcanus (Pallas), Anopheles sacharovi Favre, Culex theileri Theobald, Culex tritaeniorhynchus Giles, Culex pipiens Linnaeus, Uranotaenia unguiculata Edwards and belonging to four genera. Cx. tritaeniorhynchus constituted the most abundant species. It is the second recorded occurrence of this species in Greece, but the first time that a high population of this mosquito species is recorded in the country. In all three years, the total population density of mosquitoes was found to be higher in early August. The number of immatures of all species was found higher in 2009 and 2010 than in 2011, as well was that of the Cx. tritaeniorhynchus adults derived from the rearing of the collected immatures. This regularity is probably due to the lack of water in the rice field in early August 2011. Cx. tritaeniorhynchus was found to be the most abundant species after the rearing of immatures representing 85.1%, 93.5% and 96.1% of the total number of the mosquito adults in 2009, 2010 and 2011, respectively. The rice culturing practices may have affected the seasonal occurrence of mosquito immatures in all of the study years. Copyright © 2014 Elsevier B.V. All rights reserved.

Response of adult mosquitoes to light-emitting diodes placed in resting boxes and in the field.

PubMed

Bentley, Michael T; Kaufman, Phillip E; Kline, Daniel L; Hogsette, Jerome A

2009-09-01

The response of adult mosquitoes to 4 light-emitting diode (LED) wavelengths was evaluated using diode-equipped sticky cards (DESCs) and diode-equipped resting boxes at 2 sites in north central Florida. Wavelengths evaluated were blue (470 nm), green (502 nm), red (660 nm), and infrared (IR) (860 nm). When trapping with DESCs, 15 mosquito species from 7 genera (Aedes, Anopheles, Coquillettidia, Culex, Mansonia, Psorophora, and Uranotaenia) were captured. Overall, approximately 43.8% of all mosquitoes were trapped on DESCs fitted with green LEDs. Significantly more females of Aedes infirmatus, Aedes vexans, and Culex nigripalpus were captured on DESCs fitted with blue LEDs compared with red or IR LEDs. DESCs with blue LEDs captured significantly more Culex erraticus females than those with IR LEDs. Using resting boxes, 12 species from 5 genera (Anopheles, Coquillettidia, Culex, Mansonia, and Uranotaenia) were collected. Resting boxes without LEDs captured 1,585 mosquitoes (22.2% of total). The fewest number of mosquitoes (16.7%) were collected from boxes affixed with the blue LEDs. Significantly more Anopheles quadrimaculatus females were aspirated from resting boxes fitted with red and IR LEDs than from those with blue or green LEDs, or from the unlit control. Blood-fed mosquitoes were recovered in highest numbers from unlit resting boxes, followed by resting boxes fitted with green, IR, and blue LEDs. Culex erraticus accounted for the majority of blood-fed mosquitoes followed by Coquillettidia perturbans. No blood-fed mosquitoes were recovered from resting boxes fitted with red LEDs.

Measurement of landing mosquito density on humans

USDA-ARS?s Scientific Manuscript database

In conventional vector surveillance systems, adult mosquito density and the rate of human-mosquito contact is estimated from the mosquito numbers captured in mechanical traps. However, the design of the traps, their placement in the habitat and operating time, microclimate, and other environmental ...

Hydrology and Mosquito Population Dynamics around a Hydropower Reservoir in Africa

NASA Astrophysics Data System (ADS)

Endo, N.; Eltahir, E. A.

2013-12-01

Malaria is associated with dams because their reservoirs provide mosquitoes, the vector of malaria, with permanent breeding sites. The risk of contracting malaria is likely to be enhanced following the increasing trend of hydropower dam construction to satisfy the expanding energy needs in developing countries. A close examination of its adverse health impacts is critical in the design, construction, and operation phases. We will present results of extensive field studies in 2012 and 2013 around the Koka Reservoir, Ethiopia. The results uncover the importance of reservoir management especially after the rainy seasons. Furthermore, we show the capability of a newly modified hydrology, entomology and malaria transmission simulator, HYDREMATS (Bomblies et al, 2008), and its potential as a tool for evaluating environmental management strategies to control malaria. HYDREMATS was developed to represent how the hydrology in nearby villages is impacted by the reservoir system, and the role of different types of vector ecologies associated with different Anopheles mosquito species. The hydrology component of HYDREMATS simulates three different mosquito breeding habitats: rain-fed pools, groundwater pools, and shoreline water. The entomology component simulates the life cycles of An. funestus and An. arabiensis, the two main vectors around the reservoir. The model was calibrated over the 2012-2013 period. The impact of reservoir water level management on the mosquito population is explored based on numerical model simulations and field experiments.

Evidence of carbamate resistance in urban populations of Anopheles gambiae s.s. mosquitoes resistant to DDT and deltamethrin insecticides in Lagos, South-Western Nigeria

PubMed Central

2012-01-01

Background Resistance monitoring is essential in ensuring the success of insecticide based vector control programmes. This study was carried out to assess the susceptibility status of urban populations of Anopheles gambiae to carbamate insecticide being considered for vector control in mosquito populations previously reported to be resistant to DDT and permethrin. Methods Two – three day old adult female Anopheles mosquitoes reared from larval collections in 11 study sites from Local Government Areas of Lagos were exposed to test papers impregnated with DDT 4%, deltamethrin 0.05% and propoxur 0.1% insecticides. Additional tests were carried out to determine the susceptibility status of the Anopheles gambiae population to bendiocarb insecticide. Members of the A. gambiae complex, the molecular forms, were identified by PCR assays. The involvement of metabolic enzymes in carbamate resistance was assessed using Piperonyl butoxide (PBO) synergist assays. The presence of kdr-w/e and ace-1R point mutations responsible for DDT-pyrethroid and carbamate resistance mechanisms was also investigated by PCR. Results Propoxur resistance was found in 10 out of the 11 study sites. Resistance to three classes of insecticides was observed in five urban localities. Mortality rates in mosquitoes exposed to deltamethrin and propoxur did not show any significant difference (P > 0.05) but was significantly higher (P < 0.05) in populations exposed to DDT. All mosquitoes tested were identified as A. gambiae s.s (M form). The kdr -w point mutation at allelic frequencies between 45%-77% was identified as one of the resistant mechanisms responsible for DDT and pyrethroid resistance. Ace-1R point mutation was absent in the carbamate resistant population. However, the possible involvement of metabolic resistance was confirmed by synergistic assays conducted. Conclusion Evidence of carbamate resistance in A. gambiae populations already harbouring resistance to DDT and permethrin is a

The Interactive Role of Immature Stage Competition, Cohort Overlap, and Resource Limitation on the Population Viability of the Treehole Mosquito Aedes triseriatus (Diptera: Culicidae).

PubMed

Hanly, Patrick J; Haase, Amanda T

2016-05-01

The size and success of epidemiologically significant adult mosquito populations are inherently tied to the conditions of the aquatic habitat in which juvenile stages grow until eclosion. While resource competition and quality are well-established controls to juvenile growth and survival, the implications to overall population rates of increase are less understood due to the large sample sizes needed to parameterize population models for all five juvenile life stages under multiple environmental and demographic conditions. Here, we present the results of >4,300 trials of wild-caught Aedes triseriatus (Say, 1823) larvae and pupae reared under varying resource quantity crossed by the presence or absence of competition within a single cohort as well as multiple overlapping cohorts. Demographic projection was used to make predictions of the realized growth rates of simulated Ae. triseriatus populations across the range of potential Ae. triseriatus fecundity. Further, to inform control efforts on juvenile habitat, we constructed a stochastic simulation to estimate the rates of successful emergence from habitats under different resource regimes and levels of cohort overlap. We found that while Ae. triseriatus populations were robust to low resource levels and competition within a cohort, the combination of these stressors with multiple cohort overlap led to self-limitation or complete collapse of mosquito populations. Despite this importance of intraspecific competition to population viability, the stochastic simulation revealed only a modest self-limitation of adult emergence, with the clear implication that high-resource habitats are a higher value control target. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Exploiting mosquito sugar feeding to detect mosquito-borne pathogens

PubMed Central

Hall-Mendelin, Sonja; Ritchie, Scott A.; Johansen, Cheryl A.; Zborowski, Paul; Cortis, Giles; Dandridge, Scott; Hall, Roy A.; van den Hurk, Andrew F.

2010-01-01

Arthropod-borne viruses (arboviruses) represent a global public health problem, with dengue viruses causing millions of infections annually, while emerging arboviruses, such as West Nile, Japanese encephalitis, and chikungunya viruses have dramatically expanded their geographical ranges. Surveillance of arboviruses provides vital data regarding their prevalence and distribution that may be utilized for biosecurity measures and the implementation of disease control strategies. However, current surveillance methods that involve detection of virus in mosquito populations or sero-conversion in vertebrate hosts are laborious, expensive, and logistically problematic. We report a unique arbovirus surveillance system to detect arboviruses that exploits the process whereby mosquitoes expectorate virus in their saliva during sugar feeding. In this system, infected mosquitoes captured by CO2-baited updraft box traps are allowed to feed on honey-soaked nucleic acid preservation cards within the trap. The cards are then analyzed for expectorated virus using real-time reverse transcription-PCR. In field trials, this system detected the presence of Ross River and Barmah Forest viruses in multiple traps deployed at two locations in Australia. Viral RNA was preserved for at least seven days on the cards, allowing for long-term placement of traps and continuous collection of data documenting virus presence in mosquito populations. Furthermore no mosquito handling or processing was required and cards were conveniently shipped to the laboratory overnight. The simplicity and efficacy of this approach has the potential to transform current approaches to vector-borne disease surveillance by streamlining the monitoring of pathogens in vector populations. PMID:20534559

Regulation of salt marsh mosquito populations by the 18.6-yr lunar-nodal cycle.

PubMed

Rochlin, Ilia; Morris, James T

2017-08-01

The 18.6-yr lunar-nodal cycle drives changes in tidal amplitude globally, affecting coastal habitat formation, species and communities inhabiting rocky shores, and salt marsh vegetation. However, the cycle's influence on salt marsh fauna lacked sufficient long-term data for testing its effect. We circumvented this problem by using salt marsh mosquito records obtained over a period of over four decades in two estuaries in the northeastern USA. Salt marsh mosquito habitat is near the highest tide level where the impact of the nodal cycle on flood frequency is greatest. Wavelet spectral and cross-correlation analyses revealed periodicity in salt marsh mosquito abundance that was negatively correlated with tidal amplitude. Tidal amplitude was a significant predictor of salt marsh mosquito abundance with the cycle maxima coinciding with lower mosquito populations, possibly due to access by predatory fish. However, these effects were detected only at the location with extensive salt marsh habitat and astronomical tides and were weakened or lacked significance at the location with small microtidal salt marshes and wind-driven tides. Mosquitoes can serve as proxy indicators for numerous invertebrate species on the salt marsh. These predictable cycles and their effects need to be taken into consideration when investigating, restoring, or managing intertidal communities that are also facing sea-level rise. © 2017 by the Ecological Society of America.

Mosquito population dynamic (Diptera: Culicidae) in a eutrophised dam.

PubMed

Wermelinger, E D; Benigno, C V; Machado, R N M; Cabello, P H; Meira, A M; Ferreira, A P; Zanuncio, J C

2012-11-01

This study observed the mosquito population in a rural eutrophised dam. Larvae of L3 and L4 stages and pupae were dipped out during twelve month collections and the reared to the adult stage for identification. The collections were done along nine metres from the edge of the dam divided in three parts (P1, P2 and P3), each part being 3 m long. P1 did not have vegetation (grass) along its edge,which would reach or sink into the water to promote some shade on the marginal water. A total of 217 adults of four species was identified with the following constancies and frequencies: Culex quinquefasciatus (Say, 1823) (83% and 40.6%), Anopheles (Nyssorhynchus) evansae (Brèthes, 1926) (92% and 26.7%), Anopheles (Nyssorhynchus) rangeli (Gabaldon, Cova Garcia and Lopez, 1940) (83% and 14.3%) and Culex nigripalpus (Theobald, 1901) (33% and 18.4%). C. quinquefasciatus, A. evansae, A. rangeli and C. nigripalpus were more frequent in the quarters Nov./Dec./Jan. (85.7%), May/June/July (75%), Aug./Sept./Oct. (29.4%) and Aug./Sept./Oct. (23.5%) particularly in the months of December (88.4%) Sept.tember (48.94), (38.3) and August (47.62) respectively. The presence of C. quinquefasciatus and the high incidence of Daphinia sp. and also the levels of Organic Nitrogen (0.28 mg/L) and of total Phosphorus (0.02 mg/L) are indications of the eutrophication of the dam. There was a difference regarding the total of Anopheles (A. avansae + A. rangeli) and Culex species (C. quinquefasciatus + C. nigripalpis) between P1 and P2 (χ(2) = 0.0097), P1 and P3 (χ(2) = 0.0005), but not between P2 and P3 (χ(2) = 0.2045).The high C. quinquefasciatus constancy and frequency were confirmed to be a good biological indicator for a eutrophised environment and A. evansae showed a good potential for this environment. Vegetation can be an important factor for anopheline population dynamic also in eutrophic breeding sites.

Pyrethroid insecticides maintain repellent effect on knock-down resistant populations of Aedes aegypti mosquitoes.

PubMed

Bowman, Natalie M; Akialis, Kristin; Cave, Grayson; Barrera, Roberto; Apperson, Charles S; Meshnick, Steven R

2018-01-01

Pyrethroid-treated clothing is commonly worn for protection against mosquitoes; pyrethroids are both insecticides and repellents. Pyrethroid resistance has become increasingly common in Aedes aegypti, the vector of dengue, Zika, and other arboviruses, but it is not clear whether resistance is associated with reductions in repellency. In order to determine whether long-lasting permethrin impregnated (LLPI) clothing is protective, we used Aedes aegypti from New Orleans, LA (pyrethroid-sensitive) and San Juan, PR (resistant) to measure both lethality and repellency. PCR and Sanger sequencing were used to confirm resistance status by detecting mutations in the kdr gene at positions 1016 and 1534. Arm-in-cage trials of 100 Aedes aegypti females from both populations were performed for 10 minutes to bare arm or an arm clothed in untreated military camouflage or military camouflage impregnated with deltamethrin, permethrin, or etofenprox. Trials were repeated 4-5 times on different days. Number of landings, number of blood meals, and immediate and 24-hour mortality were recorded. Mortality was extremely low in all trials. Compared to untreated cloth, mosquitoes demonstrated a trend towards a 2%-63% reduction in landings and a statistically significant 78-100% reduction in blood feeding on pyrethroid-treated cloth for most insecticides. Effects were observed in both pyrethroid-sensitive and pyrethroid-resistant mosquito populations. Our data show that kdr mutations are associated with pyrethroid resistance but are likely not the only contributors. Pyrethroids appear to maintain repellent effect against resistant mosquitoes. This finding suggests that even in places where pyrethroid resistance is widespread, permethrin still has a role for use as a repellent on clothing to protect against mosquito bites.

Intricate predatory decisions by a mosquito-specialist spider from Malaysia

PubMed Central

Jackson, Robert R.; Li, Daiqin; Woon, Jeremy R. W.; Hashim, Rosli; Cross, Fiona R.

2014-01-01

Paracyrba wanlessi is a southeast Asian jumping spider (Salticidae) that lives in the hollow internodes of fallen bamboo and preys on the larvae, pupae and adults of mosquitoes. In contrast to Evarcha culicivora, an East African salticid that is also known for actively targeting mosquitoes as preferred prey, there was no evidence of P. wanlessi choosing mosquitoes on the basis of species, sex or diet. However, our findings show that P. wanlessi chooses mosquitoes significantly more often than a variety of other prey types, regardless of whether the prey are in or away from water, and regardless of whether the mosquitoes are adults or juveniles. Moreover, a preference for mosquito larvae, pupae and adults is expressed regardless of whether test spiders are maintained on a diet of terrestrial or aquatic prey and regardless of whether the diet includes or excludes mosquitoes. Congruence of an environmental factor (in water versus away from water) with prey type (aquatic versus terrestrial mosquitoes) appeared to be important and yet, even when the prey were in the incongruent environment, P. wanlessi continued to choose mosquitoes more often than other prey. PMID:26064534

Detection of the Invasive Mosquito Species Aedes (Stegomyia) albopictus (Diptera: Culicidae) in Portugal.

PubMed

Osório, Hugo Costa; Zé-Zé, Líbia; Neto, Maria; Silva, Sílvia; Marques, Fátima; Silva, Ana Sofia; Alves, Maria João

2018-04-21

The Asian tiger mosquito Aedes albopictus is an invasive mosquito originating from the Asia-Pacific region. This species is of major concern to public and veterinary health because of its vector role in the transmission of several pathogens, such as chikungunya, dengue, and Zika viruses. In Portugal, a National Vector Surveillance Network (REde de VIgilância de VEctores—REVIVE) is responsible for the surveillance of autochthonous, but also invasive, mosquito species at points of entry, such as airports, ports, storage areas, and specific border regions with Spain. At these locations, networks of mosquito traps are set and maintained under surveillance throughout the year. In September 2017, Ae. albopictus was detected for the first time in a tyre company located in the North of Portugal. Molecular typing was performed, and a preliminary phylogenetic analysis indicated a high similarity with sequences of Ae. albopictus collected in Europe. A prompt surveillance response was locally implemented to determine its dispersal and abundance, and adult mosquitoes were screened for the presence of arboviral RNA. A total of 103 specimens, 52 immatures and 51 adults, were collected. No pathogenic viruses were detected. Despite the obtained results suggest low abundance of the population locally introduced, the risk of dispersal and potential establishment of Ae. albopictus in Portugal has raised concern for autochthonous mosquito-borne disease outbreaks.

Detection of the Invasive Mosquito Species Aedes (Stegomyia) albopictus (Diptera: Culicidae) in Portugal

PubMed Central

Osório, Hugo Costa; Zé-Zé, Líbia; Neto, Maria; Silva, Sílvia; Marques, Fátima; Silva, Ana Sofia; Alves, Maria João

2018-01-01

The Asian tiger mosquito Aedes albopictus is an invasive mosquito originating from the Asia-Pacific region. This species is of major concern to public and veterinary health because of its vector role in the transmission of several pathogens, such as chikungunya, dengue, and Zika viruses. In Portugal, a National Vector Surveillance Network (REde de VIgilância de VEctores—REVIVE) is responsible for the surveillance of autochthonous, but also invasive, mosquito species at points of entry, such as airports, ports, storage areas, and specific border regions with Spain. At these locations, networks of mosquito traps are set and maintained under surveillance throughout the year. In September 2017, Ae. albopictus was detected for the first time in a tyre company located in the North of Portugal. Molecular typing was performed, and a preliminary phylogenetic analysis indicated a high similarity with sequences of Ae. albopictus collected in Europe. A prompt surveillance response was locally implemented to determine its dispersal and abundance, and adult mosquitoes were screened for the presence of arboviral RNA. A total of 103 specimens, 52 immatures and 51 adults, were collected. No pathogenic viruses were detected. Despite the obtained results suggest low abundance of the population locally introduced, the risk of dispersal and potential establishment of Ae. albopictus in Portugal has raised concern for autochthonous mosquito-borne disease outbreaks. PMID:29690531

Optimization of mosquito egg production under mass rearing setting: effects of cage volume, blood meal source and adult population density for the malaria vector, Anopheles arabiensis.

PubMed

Mamai, Wadaka; Bimbile-Somda, Nanwintoum S; Maiga, Hamidou; Juarez, José Guillermo; Muosa, Zaynab A I; Ali, Adel Barakat; Lees, Rosemary Susan; Gilles, Jeremie R L

2017-01-24

Anopheles arabiensis is one of the major malaria vectors that put millions of people in endemic countries at risk. Mass-rearing of this mosquito is crucial for strategies that use sterile insect technique to suppress vector populations. The sterile insect technique (SIT) package for this mosquito species is being developed by the Insect Pest Control Subprogramme of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. To improve mass-rearing outcomes for An. arabiensis, the question of whether the egg production by females would be affected by the size of the adult holding cages, the source of the blood meal and the total number of pupae that could be loaded into the cages was addressed and finally the impact of adding additional pupae to the cage daily to maintain adult numbers on egg productivity assessed. Mass production cages of two different volumes, two different sources of blood meal (bovine and porcine) and two different population densities (cages originally loaded with either 15,000 or 20,000 pupae) were tested and evaluated on the basis of eggs produced/cage or per female. Males and females pupae with a ratio of 1:1 were added to the cages at day 1 and 2 of pupation. The emerging adults had constant access to 5% sugar solution and blood fed via the Hemotek membrane feeding system. Eggs were collected either twice a week or daily. A generalized linear model was used to identify factors which gave significantly higher egg production. Neither cage volume nor blood meal source affected egg production per cage or per female. However, increasing population density to 20,000 pupae had a negative effect on eggs produced per cage and per female. Although high density negatively impacted egg production, adding 1000 daily additional pupae compensating for daily mortality resulted in a substantial increase in egg production. Moreover, in all tests the first and the third egg batches collected were significantly higher than others eggs batches

Analysis of population structure and insecticide resistance in mosquitoes of the genus Culex, Anopheles and Aedes from different environments of Greece with a history of mosquito borne disease transmission.

PubMed

Fotakis, Emmanouil A; Chaskopoulou, Alexandra; Grigoraki, Linda; Tsiamantas, Alexandros; Kounadi, Stella; Georgiou, Loukas; Vontas, John

2017-10-01

Greece has been recently affected by several mosquito borne diseases with the West Nile Virus (WNV) outbreak in 2010 being one of the largest reported in Europe. Currently at the epicenter of an economic and refugee crisis and visited by over 16 million tourists a year the integrated management of diseases transmitted by mosquitoes is a public health and economic priority. Vector control programs rely mainly on insecticides, however data on insecticide resistance and the mosquito fauna is essential for successful applications. We determined the mosquito species composition and population dynamics in areas of increased vulnerability to vector borne disease transmission, as well as investigated the resistance status of major nuisance and disease vectors to insecticides. High mosquito densities were recorded in Thessaloniki and Evros, with Aedes caspius, a nuisance species, Culex pipiens, a known vector of WNV and Anopheles hyrcanus a potential vector of malaria being among the most prevalent species. Both vector species populations reached their peak in late summer. Aedes albopictus was recorded at high densities in Thessaloniki, but not in Evros. Notably, Cx. pipiens hybrids, which show an opportunistic biting behavior and are suspected to be involved in the transmission of the WNV, were recorded in considerable numbers in Thessaloniki and Attica. Culex pipiens and An. hyrcanus, but not Ae. caspius mosquitoes, showed moderate levels of resistance to deltamethrin. The presence of resistance in areas not exposed to vector control indicates that other factors could be selecting for resistance, i.e. pesticide applications for agriculture. Both L1014F and L101C kdr mutations were detected in Cx. pipiens populations. Anopheles hyrcanus resistance was not associated with mutations at the L1014 site. The Ace-1 mutations conferring insensitivity to organophosphates and carbamates were detected at low frequencies in all Cx. pipiens populations. Increased activity of P450s and

Persistent oscillations and backward bifurcation in a malaria model with varying human and mosquito populations: implications for control.

PubMed

Ngonghala, Calistus N; Teboh-Ewungkem, Miranda I; Ngwa, Gideon A

2015-06-01

We derive and study a deterministic compartmental model for malaria transmission with varying human and mosquito populations. Our model considers disease-related deaths, asymptomatic immune humans who are also infectious, as well as mosquito demography, reproduction and feeding habits. Analysis of the model reveals the existence of a backward bifurcation and persistent limit cycles whose period and size is determined by two threshold parameters: the vectorial basic reproduction number Rm, and the disease basic reproduction number R0, whose size can be reduced by reducing Rm. We conclude that malaria dynamics are indeed oscillatory when the methodology of explicitly incorporating the mosquito's demography, feeding and reproductive patterns is considered in modeling the mosquito population dynamics. A sensitivity analysis reveals important control parameters that can affect the magnitudes of Rm and R0, threshold quantities to be taken into consideration when designing control strategies. Both Rm and the intrinsic period of oscillation are shown to be highly sensitive to the mosquito's birth constant λm and the mosquito's feeding success probability pw. Control of λm can be achieved by spraying, eliminating breeding sites or moving them away from human habitats, while pw can be controlled via the use of mosquito repellant and insecticide-treated bed-nets. The disease threshold parameter R0 is shown to be highly sensitive to pw, and the intrinsic period of oscillation is also sensitive to the rate at which reproducing mosquitoes return to breeding sites. A global sensitivity and uncertainty analysis reveals that the ability of the mosquito to reproduce and uncertainties in the estimations of the rates at which exposed humans become infectious and infectious humans recover from malaria are critical in generating uncertainties in the disease classes.

An approach of the exact linearization techniques to analysis of population dynamics of the mosquito Aedes aegypti.

PubMed

Dos Reis, Célia A; Florentino, Helenice de O; Cólon, Diego; Rosa, Suélia R Fleury; Cantane, Daniela R

2018-05-01

Dengue fever, chikungunya and zika are caused by different viruses and mainly transmitted by Aedes aegypti mosquitoes. These diseases have received special attention of public health officials due to the large number of infected people in tropical and subtropical countries and the possible sequels that those diseases can cause. In severe cases, the infection can have devastating effects, affecting the central nervous system, muscles, brain and respiratory system, often resulting in death. Vaccines against these diseases are still under development and, therefore, current studies are focused on the treatment of diseases and vector (mosquito) control. This work focuses on this last topic, and presents the analysis of a mathematical model describing the population dynamics of Aedes aegypti, as well as present the design of a control law for the mosquito population (vector control) via exact linearization techniques and optimal control. This control strategy optimizes the use of resources for vector control, and focuses on the aquatic stage of the mosquito life. Theoretical and computational results are also presented. Copyright © 2017 Elsevier Inc. All rights reserved.

Mosquitoes in Moose Country: A Mosquito Survey of Northern Minnesota.

PubMed

Kinsley, A C; Moon, R D; Johnson, K; Carstensen, M; Neitzel, D; Craft, M E

2016-06-01

An adult mosquito survey was conducted at 12 sites using carbon dioxide traps in northern Minnesota throughout the summer of 2012. Specimens were counted, identified to species, sorted into pools, and tested for eastern equine encephalitis (EEEV) and West Nile virus (WNV). Our findings extend the known range of Culiseta melanura, Anopheles barberi, and An. quadrimaculatus and document the presence and abundance of 27 other mosquito taxa in the region. None of the pools tested positive for EEEV or WNV.

Spatial model for transmission of mosquito-borne diseases

NASA Astrophysics Data System (ADS)

Kon, Cynthia Mui Lian; Labadin, Jane

2015-05-01

In this paper, a generic model which takes into account spatial heterogeneity for the dynamics of mosquito-borne diseases is proposed. The dissemination of the disease is described by a system of reaction-diffusion partial differential equations. Host human and vector mosquito populations are divided into susceptible and infectious classes. Diffusion is considered to occur in all classes of both populations. Susceptible humans are infected when bitten by infectious mosquitoes. Susceptible mosquitoes bite infectious humans and become infected. The biting rate of mosquitoes is considered to be density dependent on the total human population in different locations. The system is solved numerically and results are shown.

Mosquitoes established in Lhasa city, Tibet, China

PubMed Central

2013-01-01

Background In 2009, residents of Lhasa city, Tibet Autonomous Region (TAR), China reported large numbers of mosquitoes and bites from these insects. It is unclear whether this was a new phenomenon, which species were involved, and whether these mosquitoes had established themselves in the local circumstances. Methods The present study was undertaken in six urban sites of Chengguan district Lhasa city, Tibet. Adult mosquitoes were collected by bed net trap, labor hour method and light trap in August 2009 and August 2012. The trapped adult mosquitoes were initially counted and identified according to morphological criteria, and a proportion of mosquitoes were examined more closely using a multiplex PCR assay. Results 907 mosquitoes of the Culex pipiens complex were collected in this study. Among them, 595 were females and 312 were males. There was no significant difference in mosquito density monitored by bed net trap and labor hour method in 2009 and 2012. Of 105 mosquitoes identified by multiplex PCR, 36 were pure mosquitoes (34.29%) while 69 were hybrids (65.71%). The same subspecies of Culex pipiens complex were observed by bed net trap, labor hour method and light trap in 2009 and 2012. Conclusion The local Culex pipiens complex comprises the subspecies Cx. pipiens pipiens, Cx. pipiens pallens, Cx. pipiens quinquefasciatus and its hybrids. Mosquitoes in the Cx. pipiens complex, known to be, potentially, vectors of periodic filariasis and encephalitis, are now present from one season to the next, and appear to be established in Lhasa City, TAR. PMID:24060238

Occurrence of Borrelia burgdorferi s.l. in different genera of mosquitoes (Culicidae) in Central Europe.

PubMed

Melaun, Christian; Zotzmann, Sina; Santaella, Vanesa Garcia; Werblow, Antje; Zumkowski-Xylander, Helga; Kraiczy, Peter; Klimpel, Sven

2016-03-01

Lyme disease or Lyme borreliosis is a vector-borne infectious disease caused by spirochetes of the Borrelia burgdorferi sensu lato complex. Some stages of the borrelial transmission cycle in ticks (transstadial, feeding and co-feeding) can potentially occur also in insects, particularly in mosquitoes. In the present study, adult as well as larval mosquitoes were collected at 42 different geographical locations throughout Germany. This is the first study, in which German mosquitoes were analyzed for the presence of Borrelia spp. Targeting two specific borrelial genes, flaB and ospA encoding for the subunit B of flagellin and the outer surface protein A, the results show that DNA of Borrelia afzelii, Borrelia bavariensis and Borrelia garinii could be detected in ten Culicidae species comprising four distinct genera (Aedes, Culiseta, Culex, and Ochlerotatus). Positive samples also include adult specimens raised in the laboratory from wild-caught larvae indicating that transstadial and/or transovarial transmission might occur within a given mosquito population. Copyright © 2015 Elsevier GmbH. All rights reserved.

Insecticide susceptibility of Anopheles mosquitoes changes in response to variations in the larval environment.

PubMed

Owusu, Henry F; Chitnis, Nakul; Müller, Pie

2017-06-16

Insecticide resistance threatens the success achieved through vector control in reducing the burden of malaria. An understanding of insecticide resistance mechanisms would help to develop novel tools and strategies to restore the efficacy of insecticides. Although we have substantially improved our understanding of the genetic basis of insecticide resistance over the last decade, we still know little of how environmental variations influence the mosquito phenotype. Here, we measured how variations in larval rearing conditions change the insecticide susceptibility phenotype of adult Anopheles mosquitoes. Anopheles gambiae and A. stephensi larvae were bred under different combinations of temperature, population density and nutrition, and the emerging adults were exposed to permethrin. Mosquitoes bred under different conditions showed considerable changes in mortality rates and body weight, with nutrition being the major factor. Weight is a strong predictor of insecticide susceptibility and bigger mosquitoes are more likely to survive insecticide treatment. The changes can be substantial, such that the same mosquito colony may be considered fully susceptible or highly resistant when judged by World Health Organization discriminatory concentrations. The results shown here emphasise the importance of the environmental background in developing insecticide resistance phenotypes, and caution for the interpretation of data generated by insecticide susceptibility assays.

Suppression of Aedes albopictus, the Asian tiger mosquito, using a 'hot spot' approach.

PubMed

Unlu, Isik; Klingler, Kim; Indelicato, Nicholas; Faraji, Ary; Strickman, Daniel

2016-07-01

Recent changes in climate and human behavior have led to dramatic increases in the abundance and geographic expansion of invasive mosquito vectors such as Aedes albopictus. Although source reduction has been shown to be effective in reducing mosquito populations, thousands of backyards need to be inspected during door-to-door campaigns, which is labor intensive and expensive. We identified 'hot spots' as high (five or more female or male Ae. albopictus) adult mosquito populations at very focal locations. We tested whether hot spot source reduction efforts were effective in reducing mosquito populations in the early summer season (June to July). Analysis of historical data from the study sites indicated the proportion of hot spots in the control site relative to the intervention site was much greater in 2011, when hot spot treatments were applied to the intervention site, than in 2012, 2013 and 2014 combined, when no sites were treated [OR (95% CI) = 3.9 (1.8, 8.5), Z = 3.39, P < 0.001). Hot spot treatments can be incorporated into existing integrated mosquito management programs to increase effectiveness while reducing the time, cost and effort spent on methods such as door-to-door source reduction. Published 2015. This article is a U.S. Government work and is in the public domain in the USA. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Productivity and population density estimates of the dengue vector mosquito Aedes aegypti (Stegomyia aegypti) in Australia.

PubMed

Williams, C R; Johnson, P H; Ball, T S; Ritchie, S A

2013-09-01

New mosquito control strategies centred on the modifying of populations require knowledge of existing population densities at release sites and an understanding of breeding site ecology. Using a quantitative pupal survey method, we investigated production of the dengue vector Aedes aegypti (L.) (Stegomyia aegypti) (Diptera: Culicidae) in Cairns, Queensland, Australia, and found that garden accoutrements represented the most common container type. Deliberately placed 'sentinel' containers were set at seven houses and sampled for pupae over 10 weeks during the wet season. Pupal production was approximately constant; tyres and buckets represented the most productive container types. Sentinel tyres produced the largest female mosquitoes, but were relatively rare in the field survey. We then used field-collected data to make estimates of per premises population density using three different approaches. Estimates of female Ae. aegypti abundance per premises made using the container-inhabiting mosquito simulation (CIMSiM) model [95% confidence interval (CI) 18.5-29.1 females] concorded reasonably well with estimates obtained using a standing crop calculation based on pupal collections (95% CI 8.8-22.5) and using BG-Sentinel traps and a sampling rate correction factor (95% CI 6.2-35.2). By first describing local Ae. aegypti productivity, we were able to compare three separate population density estimates which provided similar results. We anticipate that this will provide researchers and health officials with several tools with which to make estimates of population densities. © 2012 The Royal Entomological Society.

Reduced Insecticide Susceptibility in Aedes vexans (Diptera: Culicidae) Where Agricultural Pest Management Overlaps With Mosquito Abatement.

PubMed

Dunbar, Mike W; Bachmann, Amanda; Varenhorst, Adam J

2018-05-04

Mosquito abatement programs in Midwestern communities frequently exist within landscapes dominated by agriculture. Although separately managed, both agricultural pests and mosquitoes are targeted by similar classes of insecticides. As a result, there is the potential for unintended insecticide exposure to mosquito populations from agricultural pest management. To determine the impact that agricultural management practices have on mosquito insecticide susceptibility we compared the mortality of Aedes vexans (Meigen; Diptera: Culicidae) between populations sampled from locations with and without mosquito abatement in South Dakota, a region dominated by agricultural production. Collection locations were either within towns with mosquito abatement programs (n = 2; Brookings and Sioux Falls, SD) or located > 16 km from towns with mosquito abatement programs (n = 2; areas near Harrold and Willow Lake, SD). WHO bioassays were used to test susceptibly of adults to differing insecticide classes relative to their respective controls; 1) an organochlorine (dieldrin 4%), 2) an organophosphate (malathion 5%), and 3) a pyrethroid (lambda-cyhalothrin 0.05%). Corrected mortality did not significantly differ between locations with or without abatement; however, when locations were analized by proportion of developed land within the surrounding landscape pyrethroid mortality was significantly lower where crop production dominated the surrounding landscape and mosquito abatement was present. These data suggest that agricultural pest management may incidentally contribute to reduced mosquito susceptibility where overlap between agricultural pest management and mosquito abatement exists. Decoupling insecticide classes used by both agricultural and public health pest management programs may be necessary to ensure continued efficacy of pest management tools.

Multiple Cytochrome P450 genes: their constitutive overexpression and permethrin induction in insecticide resistant mosquitoes, Culex quinquefasciatus.

PubMed

Liu, Nannan; Li, Ting; Reid, William R; Yang, Ting; Zhang, Lee

2011-01-01

Four cytochrome P450 cDNAs, CYP6AA7, CYP9J40, CYP9J34, and CYP9M10, were isolated from mosquitoes, Culex quinquefasciatus. The P450 gene expression and induction by permethrin were compared for three different mosquito populations bearing different resistance phenotypes, ranging from susceptible (S-Lab), through intermediate (HAmCq(G0), the field parental population) to highly resistant (HAmCq(G8), the 8(th) generation of permethrin selected offspring of HAmCq(G0)). A strong correlation was found for P450 gene expression with the levels of resistance and following permethrin selection at the larval stage of mosquitoes, with the highest expression levels identified in HAmCq(G8), suggesting the importance of CYP6AA7, CYP9J40, CYP9J34, and CYP9M10 in the permethrin resistance of larva mosquitoes. Only CYP6AA7 showed a significant overexpression in HAmCq(G8) adult mosquitoes. Other P450 genes had similar expression levels among the mosquito populations tested, suggesting different P450 genes may be involved in the response to insecticide pressure in different developmental stages. The expression of CYP6AA7, CYP9J34, and CYP9M10 was further induced by permethrin in resistant mosquitoes. Taken together, these results indicate that multiple P450 genes are up-regulated in insecticide resistant mosquitoes through both constitutive overexpression and induction mechanisms, thus increasing the overall expression levels of P450 genes.

On the analysis of effectiveness in mass application of mosquito repellent for dengue disease prevention

NASA Astrophysics Data System (ADS)

Aldila, D.; Soewono, E.; Nuraini, N.

2012-05-01

Dengue disease has been known as one of dangerous vector-borne diseases and become serious threat in many tropical countries. With no vaccine and antiviral available until nowadays, and frequent appearance of extraordinary dengue outbreaks, many governments are forced to declare national problem for dengue. At this moment, the only method available to prevent dengue disease transmission is to combat the disease-carrying mosquitoes as well as to reduce the contact between human and mosquitoes. The fast growing dengue transmission in many countries in recent years indicates that the mosquito control programs are far from successful. The use of mosquito repellent is one possible instrument which could be used as an effective mass treatment to prevent the dengue outbreak during endemic period. Here in this paper a Susceptible-Infectious-Recovered (S-I-R) dengue transmission model with repellent mass treatment is being applied to portions of children and adult compartments. Analysis of the basic reproductive ratio (Ro) of the model is done. It is shown, with reasonable choices of portions of treated children and adults, in combination with reduction of mosquito population, the basic reproductive ratio can be significantly reduced and occurrence of endemic can be avoided. Numerical simulations are shown for various treatment scenarios.

Characterization of hemocytes from the mosquitoes Anopheles gambiae and Aedes aegypti.

PubMed

Castillo, J C; Robertson, A E; Strand, M R

2006-12-01

Hemocytes are an essential component of the mosquito immune system but current knowledge of the types of hemocytes mosquitoes produce, their relative abundance, and their functions is limited. Addressing these issues requires improved methods for collecting and maintaining mosquito hemocytes in vitro, and comparative data that address whether important vector species produce similar or different hemocyte types. Toward this end, we conducted a comparative study with Anopheles gambiae and Aedes aegypti. Collection method greatly affected the number of hemocytes and contaminants obtained from adult females of each species. Using a collection method called high injection/recovery, we concluded that hemolymph from An. gambiae and Ae. aegypti adult females contains three hemocyte types (granulocytes, oenocytoids and prohemocytes) that were distinguished from one another by a combination of morphological and functional markers. Significantly more hemocytes were recovered from An. gambiae females than Ae. aegypti. However, granulocytes were the most abundant cell type in both species while oenocytoids and prohemocytes comprised less than 10% of the total hemocyte population. The same hemocyte types were collected from larvae, pupae and adult males albeit the absolute number and proportion of each hemocyte type differed from adult females. The number of hemocytes recovered from sugar fed females declined with age but blood feeding transiently increased hemocyte abundance. Two antibodies tested as potential hemocyte markers (anti-PP06 and anti-Dox-A2) also exhibited alterations in staining patterns following immune challenge with the bacterium Escherichia coli.

Synthetic predator cues impair immune function and make the biological pesticide Bti more lethal for vector mosquitoes.

PubMed

Op De Beeck, Lin; Janssens, Lizanne; Stoks, Robby

2016-03-01

The control of vector mosquitoes is one of the biggest challenges facing humankind with the use of chemical pesticides often leading to environmental impact and the evolution of resistance. Although to a lesser extent, this also holds for Bacillus thuringiensis israelensis (Bti), the most widely used biological pesticide to control mosquito populations. This raises the need for the development of integrated pest management strategies that allow the reduction of Bti concentrations without loss of the mosquito control efficiency. To this end, we tested in a laboratory experiment the combined effects of larval exposure to a sublethal Bti concentration and predation risk cues on life history and physiology of larval and adult Culex pipiens mosquitoes. Besides natural predator kairomones and prey alarm cues, we also tested synthetic kairomones of Notonecta predators. Neither Bti nor predation risk cues affected mortality, yet when both stressors were combined mortality increased on average by 133% compared to the treatment with only predation risk cues. This synergistic interaction was also present when Bti was combined with synthetic kairomones. This was further reflected in changes of the composite index of population performance, which suggested lowered per capita growth rates in mosquitoes exposed to Bti but only when Bti was combined with synthetic kairomones. Furthermore, predation risk cues shortened larval development time, reduced mass at metamorphosis in males, and had an immunosuppressive effect in larval and adult mosquitoes which may affect the mosquito vector competence. We provide the first demonstration that synthetic kairomones may generate similar effects on prey as natural kairomones. The identified immunosuppressive effect of synthetic kairomones and the novel lethal synergism type between a biological pesticide and synthetic predator kairomones provide an important proof of principle illustrating the potential of this combination for integrated

Present Day and Future Population Dynamics of the Dengue Vector Mosquito Aedes aegypti Using a Water Container Energy Balance Model

NASA Astrophysics Data System (ADS)

Steinhoff, D.

2017-12-01

Dengue infections are estimated to total nearly 400 million per year worldwide, with both the geographic range and the magnitude of infections having increased in the past 50 years. The primary dengue vector mosquito Aedes aegypti is closely associated with humans. It lives exclusively in urban and semi-urban areas, preferentially bites humans, and spends its developmental stages in artificial water containers. Climate regulates the development of Ae. aegypti immature mosquitoes in artificial containers. Potential containers for Ae. aegypti immature development include, but are not limited to, small sundry items (e.g., bottles, cans, plastic containers), buckets, tires, barrels, tanks, and cisterns. Successful development of immature mosquitoes from eggs to larvae, pupae, and adults is largely dependent on the availability of water and the thermal properties of the water in the containers. An energy balance container model termed the Water Height And Temperature in Container Habitats Energy Model (WHATCH'EM) solves for water temperature and height for user-specified containers with readily available meteorological data. Output from WHATCH'EM is used to estimate development parameters for the immature life stages of the Ae. aegypti mosquito, allowing for assessment of habitat suitability across varying natural environments. Variability amongst different artificial containers (e.g., size, color, material, shape), shading scenarios, and water availability scenarios is also addressed. WHATCH'EM is also coupled with an Ae. aegypti life cycle model to include the effects of the aforementioned factors on survival. Projections of future climate scenarios that take into account changes not only in temperature but also precipitation, humidity, and radiative effects are used in WHATCH'EM to estimate how Ae. aegypti population dynamics may change.

Impact of slow-release Bacillus sphaericus granules on mosquito populations followed in a tropical urban environment.

PubMed

Skovmand, Ole; Ouedraogo, Thierry D A; Sanogo, Edith; Samuelsen, Helle; Toé, Lea P; Baldet, Thierry

2009-01-01

A floating, slow-release, granular formulation of Bacillus sphaericus (Neide) was used to control mosquito larvae in two suburban areas of two tropical cities: Ouagadougou and Bobo-Dioulasso, Burkina Faso. A circular area of 2 km2, diameter 1,600 m, was treated in each city using a similar, smaller area 1 km away as an untreated control. Mosquito captures were made in houses in four concentric circles, from the periphery to the center; each circle was 50 m in width. Mosquitoes were captured in CDC light traps or from human landings. More than 95% of the mosquitoes were Culex quinquefasciatus (Say) (Diptera: Culicidae). The human landing catches provided twice as many mosquitoes as did the CDC traps/night/house. The treatments resulted in important reductions relative to the control area and to preintervention captures. The reduction was more prominent in the inner circle (up to 90%) than in the outer circle (50-70%), presumably because of the impact of immigrating mosquitoes from nontreated breeding sites around the intervention area. This effect was more pronounced for light trap catches than from human landings. The impact of treatment was also measured as the mean ratio of mosquito density in the two outer circles to that of the two inner circles. This ratio was approximately 1:1 before the intervention and reached 1:0.43 during the intervention. This comparison does not depend on the assumption that, in the absence of intervention, the mosquito population development in the two areas would have been identical, but does depend on the homogeneity of the intervention area. The study showed that it is possible to organize mosquito control in a tropical, urban environment by forming and rapidly training teams of young people to carry out the mosquito control mostly using a biopesticide that can be applied without any tools except an iron bar to lift lids on some cesspits.

Development of the gravid Aedes trap for the capture of adult female container-exploiting mosquitoes (Diptera: Culicidae).

PubMed

Eiras, Alvaro E; Buhagiar, Tamara S; Ritchie, Scott A

2014-01-01

Monitoring dengue vector control by sampling adult Aedes aegypti (L.) recently has been used to replace both larval and pupal surveys. We have developed and evaluated the Gravid Aedes Trap (GAT) through a sequential behavioral study. The GAT does not require electricity to function, and trapped mosquitoes are identified easily during trap inspections. The GAT concept relies on visual and olfactory cues to lure gravid Ae. aegypti and an insecticide to kill trapped mosquitoes. Gravid mosquitoes are lured to a black bucket base containing oviposition attractant (infusion) and are trapped in a translucent chamber impregnated with a pyrethroid insecticide where they are killed within 3-15 min. In semifield observations, the GAT captured a significantly higher proportion of gravid mosquitoes than the double sticky ovitrap. We also demonstrated that the visual cues of the prototype GAT-LgBF (large black base bucket with a black funnel at the top of the translucent chamber) captured a significantly higher proportion of gravid mosquitoes than the other prototypes. The visual contrast created by the addition of a white lid to the top of the black funnel significantly increased the number of captured gravid mosquitoes when compared with the GAT-LgBF in semifield trials. We conclude that the GAT is more efficient in recapturing gravid Ae. aegypti when compared with sticky ovitraps. The GAT is an effective, practical, low cost, and easily transportable trap, features that are essential in large-scale monitoring programs, particularly in areas where funding is limited.

Risk assessment for adult butterflies exposed to the mosquito control pesticide naled.

PubMed

Bargar, Timothy A

2012-04-01

A prospective risk assessment was conducted for adult butterflies potentially exposed to the mosquito control insecticide naled. Published acute mortality data, exposure data collected during field studies, and morphometric data (total surface area and fresh body weight) for adult butterflies were combined in a probabilistic estimate of the likelihood that adult butterfly exposure to naled following aerial applications would exceed levels associated with acute mortality. Adult butterfly exposure was estimated based on the product of (1) naled residues on samplers and (2) an exposure metric that normalized total surface area for adult butterflies to their fresh weight. The likelihood that the 10th percentile refined effect estimate for adult butterflies exposed to naled would be exceeded following aerial naled applications was 67 to 80%. The greatest risk would be for butterflies in the family Lycaenidae, and the lowest risk would be for those in the family Hesperidae, assuming equivalent sensitivity to naled. A range of potential guideline naled deposition levels is presented that, if not exceeded, would reduce the risk of adult butterfly mortality. The results for this risk assessment were compared with other risk estimates for butterflies, and the implications for adult butterflies in areas targeted by aerial naled applications are discussed. Copyright © 2012 SETAC.

Risk assessment for adult butterflies exposed to the mosquito control pesticide naled

USGS Publications Warehouse

Bargar, Timothy A.

2012-01-01

A prospective risk assessment was conducted for adult butterflies potentially exposed to the mosquito control insecticide naled. Published acute mortality data, exposure data collected during field studies, and morphometric data (total surface area and fresh body weight) for adult butterflies were combined in a probabilistic estimate of the likelihood that adult butterfly exposure to naled following aerial applications would exceed levels associated with acute mortality. Adult butterfly exposure was estimated based on the product of (1) naled residues on samplers and (2) an exposure metric that normalized total surface area for adult butterflies to their fresh weight. The likelihood that the 10th percentile refined effect estimate for adult butterflies exposed to naled would be exceeded following aerial naled applications was 67 to 80%. The greatest risk would be for butterflies in the family Lycaenidae, and the lowest risk would be for those in the family Hesperidae, assuming equivalent sensitivity to naled. A range of potential guideline naled deposition levels is presented that, if not exceeded, would reduce the risk of adult butterfly mortality. The results for this risk assessment were compared with other risk estimates for butterflies, and the implications for adult butterflies in areas targeted by aerial naled applications are discussed.

Detection, monitoring, and evaluation of spatio-temporal change in mosquito populations

USDA-ARS?s Scientific Manuscript database

USDA-ARS scientists seek to implement a sampling and global information technology based system that can be used for mosquito detection and trap deployment, to estimate mosquito species composition and distribution in space and time, and for targeting and evaluation of mosquito controls. Knowledge ...

Effect of Deforestation and Land Use Changes on Mosquito Productivity and Development in Western Kenya Highlands: Implication for Malaria Risk.

PubMed

Kweka, Eliningaya J; Kimaro, Epiphania E; Munga, Stephen

2016-01-01

African highlands were known to be free of malaria for the past 50 years. However, the ever growing human population in the highlands of Africa has led to the deforestation and land coverage changes to create space for more land for cultivation, grazing, and house construction materials needs. This has lead to the creation of suitable breeding habitats, which are in open places. Decrease of canopy and forest cover has led to increased temperature both in outdoors and indoors in deforested areas. This increased temperature has resulted in the shortening of developmental stages of aquatic stages of mosquitoes and sporogony development in adult mosquitoes. Assessment of the effects of deforestation and land coverage changes (decrease), which leads to temperature changes and subsequently increases survivorship of adults and sporogony development in adult mosquitoes' body was gathered from previous data collected from 2003 to 2012 using different analysis techniques. Habitats productivity, species dynamics and abundance, mosquitoes feeding rates, and sporogony development are presented in relation to temperature changes. The effects of temperature rise due to land cover changes in highlands of western Kenya on larval developmental rates, adult sporogony developments, and malaria risk in human population were derived. Vector species dynamics and abundance in relation to land use changes have been found to change with time. This study found that, land cover changes is a key driver for the temperature rise in African highlands and increases the rate of malaria vectors Anopheles gambiae ssp., An. Funestus , and An. arabiensis colonizing the highlands. It has also significantly enhanced sporogony development rate and adult vector survival and therefore the risk of malaria transmission in the highlands.

Attractive Toxic Sugar Bait (ATSB) For Control of Mosquitoes and Its Impact on Non-Target Organisms: A Review

PubMed Central

Fiorenzano, Jodi M.; Koehler, Philip G.; Xue, Rui-De

2017-01-01

Mosquito abatement programs contend with mosquito-borne diseases, insecticidal resistance, and environmental impacts to non-target organisms. However, chemical resources are limited to a few chemical classes with similar modes of action, which has led to insecticide resistance in mosquito populations. To develop a new tool for mosquito abatement programs that control mosquitoes while combating the issues of insecticidal resistance, and has low impacts of non-target organisms, novel methods of mosquito control, such as attractive toxic sugar baits (ATSBs), are being developed. Whereas insect baiting to dissuade a behavior, or induce mortality, is not a novel concept, as it was first introduced in writings from 77 AD, mosquito baiting through toxic sugar baits (TSBs) had been quickly developing over the last 60 years. This review addresses the current body of research of ATSB by providing an overview of active ingredients (toxins) include in TSBs, attractants combined in ATSB, lethal effects on mosquito adults and larvae, impact on non-target insects, and prospects for the use of ATSB. PMID:28394284

Attractive Toxic Sugar Bait (ATSB) For Control of Mosquitoes and Its Impact on Non-Target Organisms: A Review.

PubMed

Fiorenzano, Jodi M; Koehler, Philip G; Xue, Rui-De

2017-04-10

Mosquito abatement programs contend with mosquito-borne diseases, insecticidal resistance, and environmental impacts to non-target organisms. However, chemical resources are limited to a few chemical classes with similar modes of action, which has led to insecticide resistance in mosquito populations. To develop a new tool for mosquito abatement programs that control mosquitoes while combating the issues of insecticidal resistance, and has low impacts of non-target organisms, novel methods of mosquito control, such as attractive toxic sugar baits (ATSBs), are being developed. Whereas insect baiting to dissuade a behavior, or induce mortality, is not a novel concept, as it was first introduced in writings from 77 AD, mosquito baiting through toxic sugar baits (TSBs) had been quickly developing over the last 60 years. This review addresses the current body of research of ATSB by providing an overview of active ingredients (toxins) include in TSBs, attractants combined in ATSB, lethal effects on mosquito adults and larvae, impact on non-target insects, and prospects for the use of ATSB.

Pre-West Nile virus outbreak: perceptions and practices to prevent mosquito bites and viral encephalitis in the United States.

PubMed

Herrington, James E

2003-01-01

Mosquitoes can transmit over 100 of the viruses that can cause encephalitis, meningitis, and hemorrhagic disease in humans (Chin 2000; Gubler 1996; Monath 1989). While much is known about the ecology, epidemiology, and clinical manifestations of the arboviral encephalitides (Campbell et al. 2002; Centers for Disease Control and Prevention 1997; Gubler 1998; Hayes 1989; Hubálek and Halouzka 1999), little empirical research exists regarding the U.S. population's knowledge of mosquitoes and arboviral encephalitis, particularly prior to the U.S. outbreak of West Nile virus (WNV) in 1999. A nationally representative 55-item survey instrument was successfully administered to 1,500 adults in the United States and an additional 250 adults in six states in the Northeast (Connecticut, Delaware, New Jersey, New York, Pennsylvania, and Rhode Island) regarding mosquitoes and mosquito-borne viral encephalitis. A summary outcome measure for mosquito bite prevention was created. Analyses revealed that the following were statistically significant predictors of behaviors taken to prevent mosquito bites: being concerned about being bitten by mosquitoes, perceived effectiveness of staying indoors in late afternoon and early evening was protective, perceived effectiveness that mosquito repellent is not harmful to health, owning dogs and/or cats as pets, being married, and being > or = 18-44 years old. Being concerned about being bitten by mosquitoes was the most robust predictor of behavioral action to prevent mosquito bites (OR = 7.3; 95% CI = 4.3, 12.2). Observed misperceptions and inadequate knowledge regarding insect repellents suggest increased promotion of the safety and efficacy of DEET-containing insect repellents is warranted.

Larval diet affects mosquito development and permissiveness to Plasmodium infection.

PubMed

Linenberg, Inbar; Christophides, George K; Gendrin, Mathilde

2016-12-02

The larval stages of malaria vector mosquitoes develop in water pools, feeding mostly on microorganisms and environmental detritus. Richness in the nutrient supply to larvae influences the development and metabolism of larvae and adults. Here, we investigated the effects of larval diet on the development, microbiota content and permissiveness to Plasmodium of Anopheles coluzzii. We tested three fish diets often used to rear mosquitoes in the laboratory, including two pelleted diets, Dr. Clarke's Pool Pellets and Nishikoi Fish Pellets, and one flaked diet, Tetramin Fish-Flakes. Larvae grow and develop faster and produce bigger adults when feeding on both types of pellets compared with flakes. This correlates with a higher microbiota load in pellet-fed larvae, in agreement with the known positive effect of the microbiota on mosquito development. Larval diet also significantly influences the prevalence and intensity of Plasmodium berghei infection in adults, whereby Nishikoi Fish Pellets-fed larvae develop into adults that are highly permissive to parasites and survive longer after infection. This correlates with a lower amount of Enterobacteriaceae in the midgut microbiota. Together, our results shed light on the influence of larval feeding on mosquito development, microbiota and vector competence; they also provide useful data for mosquito rearing.

Modelling and observing the role of wind in Anopheles population dynamics around a reservoir.

PubMed

Endo, Noriko; Eltahir, Elfatih A B

2018-01-25

Wind conditions, as well as other environmental conditions, are likely to influence malaria transmission through the behaviours of Anopheles mosquitoes, especially around water-resource reservoirs. Wind-induced waves in a reservoir impose mortality on aquatic-stage mosquitoes. Mosquitoes' host-seeking activity is also influenced by wind through dispersion of [Formula: see text]. However, no malaria transmission model exists to date that simulated those impacts of wind mechanistically. A modelling framework for simulating the three important effects of wind on the behaviours of mosquito is developed: attraction of adult mosquitoes through dispersion of [Formula: see text] ([Formula: see text] attraction), advection of adult mosquitoes (advection), and aquatic-stage mortality due to wind-induced surface waves (waves). The framework was incorporated in a mechanistic malaria transmission simulator, HYDREMATS. The performance of the extended simulator was compared with the observed population dynamics of the Anopheles mosquitoes at a village adjacent to the Koka Reservoir in Ethiopia. The observed population dynamics of the Anopheles mosquitoes were reproduced with some reasonable accuracy in HYDREMATS that includes the representation of the wind effects. HYDREMATS without the wind model failed to do so. Offshore wind explained the increase in Anopheles population that cannot be expected from other environmental conditions alone. Around large water bodies such as reservoirs, the role of wind in the dynamics of Anopheles population, hence in malaria transmission, can be significant. Modelling the impacts of wind on the behaviours of Anopheles mosquitoes aids in reproducing the seasonality of malaria transmission and in estimation of the risk of malaria around reservoirs.

Detection of dengue virus in individual Aedes aegypti mosquitoes in Delhi, India.

PubMed

Vikram, Kumar; Nagpal, B N; Pande, Veena; Srivastava, Aruna; Saxena, Rekha; Singh, Himmat; Gupta, Sanjeev K; Tuli, N R; Yadav, N K; Olivier, Telle; Richard, Paul; Valecha, Neena

2015-06-01

Delhi, the capital city of India, has so far witnessed several outbreaks of dengue fever since 1967 (last one reported in 2013). Improved virological and entomological surveillance are the only tools that can help in prevention of dengue as well as in the development of dengue control programmes. The aim of the study was to conduct a prospective field study to detect dengue virus in adult Aedes aegypti mosquitoes collected from various localities represented by different socioeconomic groups in Delhi. The study areas were selected and categorized into high, medium and low income groups on the basis of socioeconomical characteristics of the resident population, where dengue cases were reported during the past three years by MCD. Dengue viral infection was detected in the head squash of each adult mosquito by immunofluorescent assay (IFA) employing monoclonal antibodies against dengue virus (DENV). A total of 2408 females and 1206 males of Ae. aegypti were collected and tested by IFA. Out of 2408 Ae. aegypti females, 14 were found positive, with minimum infection rate (MIR) of 5.8 per 1000 mosquitoes. Among the 18 study areas, 11 localities were found positive for dengue virus infection. Low income group (LIG) areas showed highest mosquito infectivity (9.8), followed by medium income group (MIG), i.e. 6.2; while least was observed in high income group (HIG), i.e. 1.3. No vertical transmission of dengue virus could be detected in 1206 Ae. aegypti males collected. The study concludes that there was high MIR in the identified localities of low and medium income groups. Estimation of MIR in a female Aedes mosquito in the existing arsenals for dengue surveillance would be an added advantage for early warning of dengue outbreak. The presence of infected mosquitoes in identified localities of Delhi was alarming and require rigorous vector surveillance so that the severe outbreaks can be prevented.

Transgenic Mosquitoes - Fact or Fiction?

PubMed

Wilke, André B B; Beier, John C; Benelli, Giovanni

2018-06-01

Technologies for controlling mosquito vectors based on genetic manipulation and the release of genetically modified mosquitoes (GMMs) are gaining ground. However, concrete epidemiological evidence of their effectiveness, sustainability, and impact on the environment and nontarget species is lacking; no reliable ecological evidence on the potential interactions among GMMs, target populations, and other mosquito species populations exists; and no GMM technology has yet been approved by the WHO Vector Control Advisory Group. Our opinion is that, although GMMs may be considered a promising control tool, more studies are needed to assess their true effectiveness, risks, and benefits. Overall, several lines of evidence must be provided before GMM-based control strategies can be used under the integrated vector management framework. Copyright © 2018 Elsevier Ltd. All rights reserved.

How does competition among wild type mosquitoes influence the performance of Aedes aegypti and dissemination of Wolbachia pipientis?

PubMed Central

de Oliveira, Suellen; Villela, Daniel Antunes Maciel; Dias, Fernando Braga Stehling; Moreira, Luciano Andrade

2017-01-01

Background Wolbachia has been deployed in several countries to reduce transmission of dengue, Zika and chikungunya viruses. During releases, Wolbachia-infected females are likely to lay their eggs in local available breeding sites, which might already be colonized by local Aedes sp. mosquitoes. Therefore, there is an urgent need to estimate the deleterious effects of intra and interspecific larval competition on mosquito life history traits, especially on the duration of larval development time, larval mortality and adult size. Methodology/principal findings Three different mosquito populations were used: Ae. aegypti infected with Wolbachia (wMelBr strain), wild Ae. aegypti and wild Ae. albopictus. A total of 21 treatments explored intra and interspecific larval competition with varying larval densities, species proportions and food levels. Each treatment had eight replicates with two distinct food levels: 0.25 or 0.50 g of Chitosan and fallen avocado leaves. Overall, overcrowding reduced fitness correlates of the three populations. Ae. albopictus larvae presented lower larval mortality, shorter development time to adult and smaller wing sizes than Ae. aegypti. The presence of Wolbachia had a slight positive effect on larval biology, since infected individuals had higher survivorship than uninfected Ae. aegypti larvae. Conclusions/significance In all treatments, Ae. albopictus outperformed both wild Ae. aegypti and the Wolbachia-infected group in larval competition, irrespective of larval density and the amount of food resources. The major force that can slow down Wolbachia invasion is the population density of wild mosquitoes. Given that Ae. aegypti currently dominates in Rio, in comparison with Ae. albopictus frequency, additional attention must be given to the population density of Ae. aegypti during releases to increase the likelihood of Wolbachia invasion. PMID:28991902

Parameterization and Sensitivity Analysis of a Complex Simulation Model for Mosquito Population Dynamics, Dengue Transmission, and Their Control

PubMed Central

Ellis, Alicia M.; Garcia, Andres J.; Focks, Dana A.; Morrison, Amy C.; Scott, Thomas W.

2011-01-01

Models can be useful tools for understanding the dynamics and control of mosquito-borne disease. More detailed models may be more realistic and better suited for understanding local disease dynamics; however, evaluating model suitability, accuracy, and performance becomes increasingly difficult with greater model complexity. Sensitivity analysis is a technique that permits exploration of complex models by evaluating the sensitivity of the model to changes in parameters. Here, we present results of sensitivity analyses of two interrelated complex simulation models of mosquito population dynamics and dengue transmission. We found that dengue transmission may be influenced most by survival in each life stage of the mosquito, mosquito biting behavior, and duration of the infectious period in humans. The importance of these biological processes for vector-borne disease models and the overwhelming lack of knowledge about them make acquisition of relevant field data on these biological processes a top research priority. PMID:21813844

Use of Nicotiana tabacum L extract for anti-Aedes Aegypti mosquito paint

NASA Astrophysics Data System (ADS)

Sandralintang, Trisiana Chrysanthi; Fauzantoro, Ahmad; Hermansyah, Heri; Jufri, Mahdi; Gozan, Misri

2018-02-01

This study intended to formulate mosquito repellent paints based tobacco leaf extracts-free pyrethroid substance which is safe for users. The active substance which was added to the paint as a mosquito repellent was an extract of tobacco leaves. The result of Anti-mosquito paint formulation produced was according to the Indonesia National Standard (SNI). The results of anti-Aedes Aegypti mosquito paint effectiveness test showed that 5% concentration of tobacco extract could kill half of the mosquito population (LC50) for 2 hours, the concentration of tobacco extract between 3-5% killed half the mosquito population (LC50) during 4 hours, while 1-3% and 0-1% concentration of tobacco extract killed half the mosquito population (LC50) for 6 and 24 hours, respectively.

Stage-Structured Population Dynamics of AEDES AEGYPTI

NASA Astrophysics Data System (ADS)

Yusoff, Nuraini; Budin, Harun; Ismail, Salemah

Aedes aegypti is the main vector in the transmission of dengue fever, a vector-borne disease affecting world population living in tropical and sub-tropical countries. Better understanding of the dynamics of its population growth will help in the efforts of controlling the spread of this disease. In looking at the population dynamics of Aedes aegypti, this paper explored the stage-structured modeling of the population growth of the mosquito using the matrix population model. The life cycle of the mosquito was divided into five stages: eggs, larvae, pupae, adult1 and adult2. Developmental rates were obtained for the average Malaysian temperature and these were used in constructing the transition matrix for the matrix model. The model, which was based only on temperature, projected that the population of Aedes aegypti will blow up with time, which is not realistic. For further work, other factors need to be taken into account to obtain a more realistic result.

Mosquito-producing containers, spatial distribution, and relationship between Aedes aegypti population indices on the southern boundary of its distribution in South America (Salto, Uruguay).

PubMed

Basso, César; Caffera, Ruben M; García da Rosa, Elsa; Lairihoy, Rosario; González, Cristina; Norbis, Walter; Roche, Ingrid

2012-12-01

A study was conducted in the city of Salto, Uruguay, to identify mosquito-producing containers, the spatial distribution of mosquitoes and the relationship between the different population indices of Aedes aegypti. On each of 312 premises visited, water-filled containers and immature Ae. aegypti mosquitoes were identified. The containers were counted and classified into six categories. Pupae per person and Stegomyia indices were calculated. Pupae per person were represented spatially. The number of each type of container and number of mosquitoes in each were analyzed and compared, and their spatial distribution was analyzed. No significant differences in the number of the different types of containers with mosquitoes or in the number of mosquitoes in each were found. The distribution of the containers with mosquito was random and the distribution of mosquitoes by type of container was aggregated or highly aggregated.

Mosquito-Producing Containers, Spatial Distribution, and Relationship between Aedes aegypti Population Indices on the Southern Boundary of its Distribution in South America (Salto, Uruguay)

PubMed Central

Basso, César; Caffera, Ruben M.; García da Rosa, Elsa; Lairihoy, Rosario; González, Cristina; Norbis, Walter; Roche, Ingrid

2012-01-01

A study was conducted in the city of Salto, Uruguay, to identify mosquito-producing containers, the spatial distribution of mosquitoes and the relationship between the different population indices of Aedes aegypti. On each of 312 premises visited, water-filled containers and immature Ae. aegypti mosquitoes were identified. The containers were counted and classified into six categories. Pupae per person and Stegomyia indices were calculated. Pupae per person were represented spatially. The number of each type of container and number of mosquitoes in each were analyzed and compared, and their spatial distribution was analyzed. No significant differences in the number of the different types of containers with mosquitoes or in the number of mosquitoes in each were found. The distribution of the containers with mosquito was random and the distribution of mosquitoes by type of container was aggregated or highly aggregated. PMID:23128295

Fine-scale variation in microclimate across an urban landscape shapes variation in mosquito population dynamics and the potential of Aedes albopictus to transmit arboviral disease

PubMed Central

Evans, Michelle V.; McClanahan, Taylor D.; Miazgowicz, Kerri L.; Tesla, Blanka

2017-01-01

Most statistical and mechanistic models used to predict mosquito-borne disease transmission incorporate climate drivers of disease transmission by utilizing environmental data collected at geographic scales that are potentially coarser than what mosquito populations may actually experience. Temperature and relative humidity can vary greatly between indoor and outdoor environments, and can be influenced strongly by variation in landscape features. In the Aedes albopictus system, we conducted a proof-of-concept study in the vicinity of the University of Georgia to explore the effects of fine-scale microclimate variation on mosquito life history and vectorial capacity (VC). We placed Ae. albopictus larvae in artificial pots distributed across three replicate sites within three different land uses–urban, suburban, and rural, which were characterized by high, intermediate, and low proportions of impervious surfaces. Data loggers were placed into each larval environment and in nearby vegetation to record daily variation in water and ambient temperature and relative humidity. The number of adults emerging from each pot and their body size and sex were recorded daily. We found mosquito microclimate to significantly vary across the season as well as with land use. Urban sites were in general warmer and less humid than suburban and rural sites, translating into decreased larval survival, smaller body sizes, and lower per capita growth rates of mosquitoes on urban sites. Dengue transmission potential was predicted to be higher in the summer than the fall. Additionally, the effects of land use on dengue transmission potential varied by season. Warm summers resulted in a higher predicted VC on the cooler, rural sites, while warmer, urban sites had a higher predicted VC during the cooler fall season. PMID:28558030

Fine-scale variation in microclimate across an urban landscape shapes variation in mosquito population dynamics and the potential of Aedes albopictus to transmit arboviral disease.

PubMed

Murdock, Courtney C; Evans, Michelle V; McClanahan, Taylor D; Miazgowicz, Kerri L; Tesla, Blanka

2017-05-01

Most statistical and mechanistic models used to predict mosquito-borne disease transmission incorporate climate drivers of disease transmission by utilizing environmental data collected at geographic scales that are potentially coarser than what mosquito populations may actually experience. Temperature and relative humidity can vary greatly between indoor and outdoor environments, and can be influenced strongly by variation in landscape features. In the Aedes albopictus system, we conducted a proof-of-concept study in the vicinity of the University of Georgia to explore the effects of fine-scale microclimate variation on mosquito life history and vectorial capacity (VC). We placed Ae. albopictus larvae in artificial pots distributed across three replicate sites within three different land uses-urban, suburban, and rural, which were characterized by high, intermediate, and low proportions of impervious surfaces. Data loggers were placed into each larval environment and in nearby vegetation to record daily variation in water and ambient temperature and relative humidity. The number of adults emerging from each pot and their body size and sex were recorded daily. We found mosquito microclimate to significantly vary across the season as well as with land use. Urban sites were in general warmer and less humid than suburban and rural sites, translating into decreased larval survival, smaller body sizes, and lower per capita growth rates of mosquitoes on urban sites. Dengue transmission potential was predicted to be higher in the summer than the fall. Additionally, the effects of land use on dengue transmission potential varied by season. Warm summers resulted in a higher predicted VC on the cooler, rural sites, while warmer, urban sites had a higher predicted VC during the cooler fall season.

Mosquito, adult feeding on the skin (image)

MedlinePlus

There are many different species of mosquito, which can carry some of the world's most common and significant infectious diseases, including West Nile, Malaria, yellow fever, viral encephalitis, and ...

Monitoring the age of mosquito populations using near-infrared spectroscopy

USDA-ARS?s Scientific Manuscript database

Mosquito control with bednets, residual sprays or fumigation remains the most effective tool for preventing vector-borne diseases such as malaria, dengue and Zika, though there are no widely used entomological methods for directly assessing its efficacy. Mosquito age is the most informative method f...

Functional characterization of three MicroRNAs of the Asian Tiger Mosquito, Aedes albopictus

PubMed Central

2013-01-01

Background Temporal and stage specific expression of microRNAs (miRNAs) in embryos, larvae, pupae and adults of Aedes albopictus showed differential expression levels across the four developmental stages, indicating their potential regulatory roles in mosquito development. The functional characterization of these miRNAs was not known. Accordingly our study evaluated the functional characterization of three miRNAs, which are temporally up-regulated in the various developmental stages of Ae. albopictus mosquitoes. Methods miRNA mimics, inhibitors and negative controls were designed and their knock-in and knock-down efficiency were analyzed by qRT-PCR after transfecting the mosquito cell lines C6/36, and also by injecting in their specific developmental stages. The functional role of each individual miRNA was analyzed with various parameters of development such as, hatching rate and hatching time in embryos, eclosion rate in larvae, longevity and fecundity in the adult mosquitoes. Results The knock-in with the specifically designed miRNA mimics showed increased levels of expression of miRNA compared with their normal controls. We confirmed these findings using qRT-PCR, both by in vitro expression in C6/36 mosquito cell lines after transfection as well as in in vivo expression in developmental stages of mosquitoes by microinjection. The knock-down of expression with the corresponding inhibitors showed a considerable decrease in the expression levels of these miRNAs and obvious functional effects in Ae. albopictus development, detected by a decrease in the hatching rate of embryos and eclosion rate in larvae and a marked reduction in longevity and fecundity in adults. Conclusion This study carried out by knock-in and knock-down of specifically and temporally expressed miRNAs in Ae. albopictus by microinjection is a novel study to delineate the importance of the miRNA expression in regulating mosquito development. The knock-down and loss of function of endogenously

3D mosquito screens to create window double screen traps for mosquito control.

PubMed

Khattab, Ayman; Jylhä, Kaisa; Hakala, Tomi; Aalto, Mikko; Malima, Robert; Kisinza, William; Honkala, Markku; Nousiainen, Pertti; Meri, Seppo

2017-08-29

reducing mosquito population size.

Evidence of natural Wolbachia infections and molecular identification of field populations of Culex pipiens complex (Diptera: Culicidae) mosquitoes in western Turkey.

PubMed

Morçiçek, Burçin; Taskin, Belgin Gocmen; Doğaç, Ersin; Doğaroğlu, Taylan; Taskin, Vatan

2018-06-01

Establishing reliable risk projection information about the distribution pattern of members of the Culex pipiens complex is of particular interest, as these mosquitoes are competent vectors for certain disease-causing pathogens. Wolbachia, a maternally inherited bacterial symbiont, are distributed in various arthropod species and can induce cytoplasmic incompatibility, i.e., reduced egg hatch, in certain crosses. It is being considered as a tool for population control of mosquito disease vectors. The Aegean region is characterized by highly populated, rural, and agricultural areas and is also on the route of the migratory birds. In this study, a fragment of the 658 bp of the mitochondrial cytochrome c oxidase subunit 1 (COI) gene, which includes the barcode region, was employed to differentiate Cx. pipiens complex species found in this region. Moreover, for the first time, the prevalence of Wolbachia endobacteria in these natural populations was examined using PCR amplification of a specific wsp gene. Our results revealed a widespread (more than 90%, n=121) presence of the highly efficient West Nile virus vector Cx. quinquefasciatus in the region. We also found that Wolbachia infection is widespread; the average prevalence was 62% in populations throughout the region. This study provided valuable information about the composition of Cx. pipiens complex mosquitoes and the prevalence of Wolbachia infection in these populations in the Aegean region. This information will be helpful in tracking mosquito-borne diseases and designing and implementing Wolbachia-based control strategies in the region. © 2018 The Society for Vector Ecology.

Mathematical assessment of the role of temperature and rainfall on mosquito population dynamics.

PubMed

Abdelrazec, Ahmed; Gumel, Abba B

2017-05-01

A new stage-structured model for the population dynamics of the mosquito (a major vector for numerous vector-borne diseases), which takes the form of a deterministic system of non-autonomous nonlinear differential equations, is designed and used to study the effect of variability in temperature and rainfall on mosquito abundance in a community. Two functional forms of eggs oviposition rate, namely the Verhulst-Pearl logistic and Maynard-Smith-Slatkin functions, are used. Rigorous analysis of the autonomous version of the model shows that, for any of the oviposition functions considered, the trivial equilibrium of the model is locally- and globally-asymptotically stable if a certain vectorial threshold quantity is less than unity. Conditions for the existence and global asymptotic stability of the non-trivial equilibrium solutions of the model are also derived. The model is shown to undergo a Hopf bifurcation under certain conditions (and that increased density-dependent competition in larval mortality reduces the likelihood of such bifurcation). The analyses reveal that the Maynard-Smith-Slatkin oviposition function sustains more oscillations than the Verhulst-Pearl logistic function (hence, it is more suited, from ecological viewpoint, for modeling the egg oviposition process). The non-autonomous model is shown to have a globally-asymptotically stable trivial periodic solution, for each of the oviposition functions, when the associated reproduction threshold is less than unity. Furthermore, this model, in the absence of density-dependent mortality rate for larvae, has a unique and globally-asymptotically stable periodic solution under certain conditions. Numerical simulations of the non-autonomous model, using mosquito surveillance and weather data from the Peel region of Ontario, Canada, show a peak mosquito abundance for temperature and rainfall values in the range [Formula: see text]C and [15-35] mm, respectively. These ranges are recorded in the Peel region

Landing response of Aedes (Stegomyia) polynesiensis mosquitoes to coloured targets.

PubMed

Chambers, E W; Bossin, H C; Ritchie, S A; Russell, R C; Dobson, S L

2013-09-01

Aedes polynesiensis Marks (Diptera: Culicidae) is the primary vector of lymphatic filariasis (LF) in the island countries and territories of the South Pacific. In the development of a novel control tool, the response of Ae. polynesiensis to six different colours (three solid fabrics, two patterned fabrics and a plastic tarp) was measured using a digital photographic system. Adult mosquitoes were placed into an environmental chamber and allowed to choose between a white target and one of six experimental targets. Mosquito landing frequency and landing duration were calculated. Adult female Ae. polynesiensis preferred all of the experimental targets to the white control target. Mosquito landing frequency was highest for the solid targets (black, navy blue and red) followed in turn by the two colour pattern targets and the polyethylene target. Mosquito landing duration was greater for experimental targets when compared with white control targets. Mosquito landing frequencies did not change over time during the course of the assay. The response of male Ae. polynesiensis was also measured when exposed to a 100% cotton black target. Male mosquitoes preferred the black target to the white control target, although at levels lower than that observed in female mosquitoes. The results suggest that future investigations evaluating the visual responses of Ae. polynesiensis mosquitoes are warranted, with a special emphasis on semi-field and field-based experiments. © 2013 The Royal Entomological Society.

Repellent action of neem cream against mosquitoes.

PubMed

Dua, V K; Nagpal, B N; Sharma, V P

1995-06-01

Neem cream was used as mosquito repellent to provide protection against Aedes albopictus, Ae. aegypti, Culex quinquefasciatus, Anopheles culicifacies and An. subpictus mosquitoes. The application of neem cream on exposed body parts @2.0 gm/person showed 78 (range 65-95), 89 (range 66-100) and 94.4 (range 66-100) per cent protection against Aedes, Culex and Anopheles mosquitoes respectively. Significant difference was observed between neem cream treated and untreated group of population for Aedes mosquitoes (p < 0.001). Application of neem cream was found to be a safe and suitable alternative to insecticide impregnated coils for personal protection against mosquitoes and one application was 68% effective for four hours.

Socioeconomic status affects mosquito (Diptera: Culicidae) larval habitat type availability and infestation level.

PubMed

Dowling, Zara; Ladeau, Shannon L; Armbruster, Peter; Biehler, Dawn; Leisnham, Paul T

2013-07-01

Mosquito populations are largely regulated by processes occurring at the larval stage. We sampled mosquito larval microhabitats (mostly water-holding containers) in six neighborhoods in the Washington, DC, area that varied in socioeconomic status (SES) and housing structure (row houses vs. stand-alone houses) to test associations among these neighborhood characteristics, microhabitat abundance and parameters, and mosquito occurrence and densities. Thirty-four percent (33.9%) of sampled microhabitats contained mosquito larvae, and 93.1% of larvae were Aedes albopictus Skuse or Culex pipiens L. Five specific container types (drains, corrugated flexible drainpipes, planters, garbage cans, and buckets) accounted for the majority of water-holding (56.0%) and mosquito-positive (50.6%) microhabitats sampled. We found no associations between SES or housing structure with total microhabitat abundance per yard, mosquito occurrence or mosquito densities per microhabitat. In contrast, container purpose varied with SES, with low SES neighborhoods having greater numbers of disused containers and lower numbers of functional containers than low and medium SES neighborhoods. Ae. albopictus were 83% more abundant in disused containers, whereas Cx. pipiens were more abundant in structural and functional containers, possibly owing to species-specific oviposition and development related to water quality. Ae. albopictus densities increased over the summer, whereas Cx. pipiens densities remained constant. Ae. albopictus is usually the dominant pest in urban areas in the eastern United States; therefore, integrated mosquito management programs should incorporate the elimination of disused containers to reduce its infestation and adult production, especially in low SES neighborhoods where they occur most frequently.

A Field Study in Benin to Investigate the Role of Mosquitoes and Other Flying Insects in the Ecology of Mycobacterium ulcerans.

PubMed

Zogo, Barnabas; Djenontin, Armel; Carolan, Kevin; Babonneau, Jeremy; Guegan, Jean-François; Eyangoh, Sara; Marion, Estelle

2015-01-01

Buruli ulcer, the third mycobacterial disease after tuberculosis and leprosy, is caused by the environmental mycobacterium M. ulcerans. There is at present no clear understanding of the exact mode(s) of transmission of M. ulcerans. Populations affected by Buruli ulcer are those living close to humid and swampy zones. The disease is associated with the creation or the extension of swampy areas, such as construction of dams or lakes for the development of agriculture. Currently, it is supposed that insects (water bugs and mosquitoes) are host and vector of M. ulcerans. The role of water bugs was clearly demonstrated by several experimental and environmental studies. However, no definitive conclusion can yet be drawn concerning the precise importance of this route of transmission. Concerning the mosquitoes, DNA was detected only in mosquitoes collected in Australia, and their role as host/vector was never studied by experimental approaches. Surprisingly, no specific study was conducted in Africa. In this context, the objective of this study was to investigate the role of mosquitoes (larvae and adults) and other flying insects in ecology of M. ulcerans. This study was conducted in a highly endemic area of Benin. Mosquitoes (adults and larvae) were collected over one year, in Buruli ulcer endemic in Benin. In parallel, to monitor the presence of M. ulcerans in environment, aquatic insects were sampled. QPCR was used to detected M. ulcerans DNA. DNA of M. ulcerans was detected in around 8.7% of aquatic insects but never in mosquitoes (larvae or adults) or in other flying insects. This study suggested that the mosquitoes don't play a pivotal role in the ecology and transmission of M. ulcerans in the studied endemic areas. However, the role of mosquitoes cannot be excluded and, we can reasonably suppose that several routes of transmission of M. ulcerans are possible through the world.

Targeting male mosquito swarms to control malaria vector density

PubMed Central

Sawadogo, Simon Peguedwinde; Niang, Abdoulaye; Bilgo, Etienne; Millogo, Azize; Maïga, Hamidou; Dabire, Roch K.; Tripet, Frederic; Diabaté, Abdoulaye

2017-01-01

Malaria control programs are being jeopardized by the spread of insecticide resistance in mosquito vector populations. It has been estimated that the spread of resistance could lead to an additional 120000 deaths per year, and interfere with the prospects for sustained control or the feasibility of achieving malaria elimination. Another complication for the development of resistance management strategies is that, in addition to insecticide resistance, mosquito behavior evolves in a manner that diminishes the impact of LLINs and IRS. Mosquitoes may circumvent LLIN and IRS control through preferential feeding and resting outside human houses and/or being active earlier in the evening before people go to sleep. Recent developments in our understanding of mosquito swarming suggest that new tools targeting mosquito swarms can be designed to cut down the high reproductive rate of malaria vectors. Targeting swarms of major malaria vectors may provide an effective control method to counteract behavioral resistance developed by mosquitoes. Here, we evaluated the impact of systematic spraying of swarms of Anopheles gambiae s.l. using a mixed carbamate and pyrethroid aerosol. The impact of this intervention on vector density, female insemination rates and the age structure of males was measured. We showed that the resulting mass killing of swarming males and some mate-seeking females resulted in a dramatic 80% decrease in population size compared to a control population. A significant decrease in female insemination rate and a significant shift in the age structure of the male population towards younger males incapable of mating were observed. This paradigm-shift study therefore demonstrates that targeting primarily males rather than females, can have a drastic impact on mosquito population. PMID:28278212

The Aquaporin gene family of the yellow fever mosquito, Aedes aegypti.

PubMed

Drake, Lisa L; Boudko, Dmitri Y; Marinotti, Osvaldo; Carpenter, Victoria K; Dawe, Angus L; Hansen, Immo A

2010-12-29

The mosquito, Aedes aegypti, is the principal vector of the Dengue and yellow fever viruses. During feeding, an adult female can take up more than its own body weight in vertebrate blood. After a blood meal females excrete large amounts of urine through their excretion system, the Malpighian tubules (MT). Diuresis starts within seconds after the mosquito starts feeding. Aquaporins (AQPs) are a family of membrane transporters that regulate the flow of water, glycerol and other small molecules across cellular membranes in both prokaryotic and eukaryotic cells. Our aim was to identify aquaporins that function as water channels, mediating transcellular water transport in MTs of adult female Ae. aegypti. Using a bioinformatics approach we screened genome databases and identified six putative AQPs in the genome of Ae. aegypti. Phylogenetic analysis showed that five of the six Ae. aegypti AQPs have high similarity to classical water-transporting AQPs of vertebrates. Using microarray, reverse transcription and real time PCR analysis we found that all six AQPs are expressed in distinct patterns in mosquito tissues/body parts. AaAQP1, 4, and 5 are strongly expressed in the adult female MT. RNAi-mediated knockdown of the MT-expressed mosquito AQPs resulted in significantly reduced diuresis. Our results support the notion that AQP1, 4, and 5 function as water transporters in the MTs of adult female Ae. aegypti mosquitoes. Our results demonstrate the importance of these AQPs for mosquito diuresis after blood ingestion and highlight their potential as targets for the development of novel vector control strategies.

Pesticide-Free Device a Fatal Attraction for Mosquitoes

NASA Technical Reports Server (NTRS)

2005-01-01

Are those pesky mosquitoes getting more entertainment out of your family picnic than you are? If the answer is yes, then it is time to reclaim your backyard with assistance from an unlikely partner. Nowadays, NASA is developing tools to track and predict the spread of the West Nile Virus on a global scale, but several years ago, the Space Agency carved out some time to collaborate with an outdoor products manufacturer in order to help control mosquito populations on a local level. The technology resulting from this union leveraged a space-age heat blanket to attract mosquitoes, which would then be eliminated without the use of harmful pesticides or chemicals. technical assistance from NASA and is an environmentally safe way to reduce the mosquito population.

Plant extracts as potential mosquito larvicides

PubMed Central

Ghosh, Anupam; Chowdhury, Nandita; Chandra, Goutam

2012-01-01

Mosquitoes act as a vector for most of the life threatening diseases like malaria, yellow fever, dengue fever, chikungunya ferver, filariasis, encephalitis, West Nile Virus infection, etc. Under the Integrated Mosquito Management (IMM), emphasis was given on the application of alternative strategies in mosquito control. The continuous application of synthetic insecticides causes development of resistance in vector species, biological magnification of toxic substances through the food chain and adverse effects on environmental quality and non target organisms including human health. Application of active toxic agents from plant extracts as an alternative mosquito control strategy was available from ancient times. These are non-toxic, easily available at affordable prices, biodegradable and show broad-spectrum target-specific activities against different species of vector mosquitoes. In this article, the current state of knowledge on phytochemical sources and mosquitocidal activity, their mechanism of action on target population, variation of their larvicidal activity according to mosquito species, instar specificity, polarity of solvents used during extraction, nature of active ingredient and promising advances made in biological control of mosquitoes by plant derived secondary metabolites have been reviewed. PMID:22771587

Plant extracts as potential mosquito larvicides.

PubMed

Ghosh, Anupam; Chowdhury, Nandita; Chandra, Goutam

2012-05-01

Mosquitoes act as a vector for most of the life threatening diseases like malaria, yellow fever, dengue fever, chikungunya ferver, filariasis, encephalitis, West Nile Virus infection, etc. Under the Integrated Mosquito Management (IMM), emphasis was given on the application of alternative strategies in mosquito control. The continuous application of synthetic insecticides causes development of resistance in vector species, biological magnification of toxic substances through the food chain and adverse effects on environmental quality and non target organisms including human health. Application of active toxic agents from plant extracts as an alternative mosquito control strategy was available from ancient times. These are non-toxic, easily available at affordable prices, biodegradable and show broad-spectrum target-specific activities against different species of vector mosquitoes. In this article, the current state of knowledge on phytochemical sources and mosquitocidal activity, their mechanism of action on target population, variation of their larvicidal activity according to mosquito species, instar specificity, polarity of solvents used during extraction, nature of active ingredient and promising advances made in biological control of mosquitoes by plant derived secondary metabolites have been reviewed.

Environmentally friendly tool to control mosquito populations without risk of insecticide resistance: the Lehmann’s funnel entry trap

PubMed Central

2013-01-01

Background Current malaria control strategies have cut down the malaria burden in many endemic areas, however the emergence and rapid spread of insecticide and drug resistance undermine the success of these efforts. There is growing concern that malaria eradication will not be achieved without the introduction of novel control tools. One approach that has been developed in the last few years is based on house screening to reduce indoor mosquito vector densities and consequently decrease malaria transmission. Here screening and trapping were combined in one tool to control mosquito populations. The trap does not require an insecticide or even an attractant, yet it effectively collects incoming resistant and susceptible mosquitoes and kills them. Results Performance of the funnel entry trap was tested in low and high malaria vector density areas. An overall reduction of 70 to 80% of mosquito density was seen in both. Species and molecular forms of Anopheles gambiae identification indicated no variation in the number of Anopheles arabiensis and the molecular forms of An. gambiae between houses and traps. Mosquitoes collected in the traps and in houses were highly resistant to pyrethroids (0.9 kdr-based mechanism). Conclusion There is a global consensus that new intervention tools are needed to cross the last miles in malaria elimination/eradication. The funnel entry trap showed excellent promise in suppressing mosquito densities even in area of high insecticide resistance. It requires no chemicals and is self-operated. PMID:23758904

Microbial Pre-exposure and Vectorial Competence of Anopheles Mosquitoes

PubMed Central

Dieme, Constentin; Rotureau, Brice; Mitri, Christian

2017-01-01

Anopheles female mosquitoes can transmit Plasmodium, the malaria parasite. During their aquatic life, wild Anopheles mosquito larvae are exposed to a huge diversity of microbes present in their breeding sites. Later, adult females often take successive blood meals that might also carry different micro-organisms, including parasites, bacteria, and viruses. Therefore, prior to Plasmodium ingestion, the mosquito biology could be modulated at different life stages by a suite of microbes present in larval breeding sites, as well as in the adult environment. In this article, we highlight several naturally relevant scenarios of Anopheles microbial pre-exposure that we assume might impact mosquito vectorial competence for the malaria parasite: (i) larval microbial exposures; (ii) protist co-infections; (iii) virus co-infections; and (iv) pathogenic bacteria co-infections. In addition, significant behavioral changes in African Anopheles vectors have been associated with increasing insecticide resistance. We discuss how these ethological modifications may also increase the repertoire of microbes to which mosquitoes could be exposed, and that might also influence their vectorial competence. Studying Plasmodium–Anopheles interactions in natural microbial environments would efficiently contribute to refining the transmission risks. PMID:29376030

Efficacy of Commercial Mosquito Traps in Capturing Phlebotomine Sand Flies in Egypt

USDA-ARS?s Scientific Manuscript database

Adult mosquito traps of four types that are marketed for homeowner use in residential settings were compared with a standard CDC light trap for efficacy in collecting phlebotomine sand flies. We evaluated the Mosquito MagnetTM Pro (MMP), the SentinelTM 360 mosquito trap (S360), the BG-SentinelTM mo...

Comparison of carbon dioxide-baited trapping systems for sampling outdoor mosquito populations in Tanzania.

PubMed

Mboera LEG; Knols BGJ; Braks MAH; Takken, W

2000-09-01

For collecting mosquitoes (Diptera: Culicidae) the outdoor catching efficiency of four types of trapping devices baited with carbon dioxide (CO2, 300 ml/ min) was evaluated and compared in two areas of Tanzania. The types of traps employed were: the CDC miniature trap with the incandescent light bulb switched on or off; electric nets (ENT) and a Counterflow Geometry (CFG) trap. In Njage, southeast Tanzania, Anopheles gambiae Giles sensu stricto was the most abundant of the seven mosquito species obtained, comprising of 74.3% of the total number caught (n=2,171). In Muheza, north-east Tanzania, Culex quinquefasciatus Say was the predominant species (90.9%) among 1,080 caught. At both localities the CFG trap was superior to the CDC trap with light-on or light-off for sampling both An. gambiae and Cx. quinquefasciatus. Efficiency of the CFG trap and ENT were similar for sampling these species of mosquitoes (P > 0.05). However, ENT was superior to the CDC trap with light-off for collecting both species. Significantly more (P < 0.05) Cx. quinquefasciatus were obtained by the CDC trap with light-off than with light-on, especially outdoors. It is concluded that both ENT and the CFG are effective tools for sampling populations of An. gambiae and Cx. quinquefasciatus outdoors.

Environmental fate model for ultra-low-volume insecticide applications used for adult mosquito management

USGS Publications Warehouse

Schleier, Jerome J.; Peterson, Robert K.D.; Irvine, Kathryn M.; Marshall, Lucy M.; Weaver, David K.; Preftakes, Collin J.

2012-01-01

One of the more effective ways of managing high densities of adult mosquitoes that vector human and animal pathogens is ultra-low-volume (ULV) aerosol applications of insecticides. The U.S. Environmental Protection Agency uses models that are not validated for ULV insecticide applications and exposure assumptions to perform their human and ecological risk assessments. Currently, there is no validated model that can accurately predict deposition of insecticides applied using ULV technology for adult mosquito management. In addition, little is known about the deposition and drift of small droplets like those used under conditions encountered during ULV applications. The objective of this study was to perform field studies to measure environmental concentrations of insecticides and to develop a validated model to predict the deposition of ULV insecticides. The final regression model was selected by minimizing the Bayesian Information Criterion and its prediction performance was evaluated using k-fold cross validation. Density of the formulation and the density and CMD interaction coefficients were the largest in the model. The results showed that as density of the formulation decreases, deposition increases. The interaction of density and CMD showed that higher density formulations and larger droplets resulted in greater deposition. These results are supported by the aerosol physics literature. A k-fold cross validation demonstrated that the mean square error of the selected regression model is not biased, and the mean square error and mean square prediction error indicated good predictive ability.

Assessing the efficiency of Wolbachia driven Aedes mosquito suppression by delay differential equations.

PubMed

Huang, Mugen; Luo, Jiaowan; Hu, Linchao; Zheng, Bo; Yu, Jianshe

2017-12-14

To suppress wild population of Aedes mosquitoes, the primary transmission vector of life-threatening diseases such as dengue, malaria, and Zika, an innovative strategy is to release male mosquitoes carrying the bacterium Wolbachia into natural areas to drive female sterility by cytoplasmic incompatibility. We develop a model of delay differential equations, incorporating the strong density restriction in the larval stage, to assess the delicate impact of life table parameters on suppression efficiency. Through mathematical analysis, we find the sufficient and necessary condition for global stability of the complete suppression state. This condition, combined with the experimental data for Aedes albopictus population in Guangzhou, helps us predict a large range of releasing intensities for suppression success. In particular, we find that if the number of released infected males is no less than four times the number of mosquitoes in wild areas, then the mosquito density in the peak season can be reduced by 95%. We introduce an index to quantify the dependence of suppression efficiency on parameters. The invariance of some quantitative properties of the index values under various perturbations of the same parameter justifies the applicability of this index, and the robustness of our modeling approach. The index yields a ranking of the sensitivity of all parameters, among which the adult mortality has the highest sensitivity and is considerably more sensitive than the natural larvae mortality. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spatial and Temporal Distributions of Mosquito Adulticide in Houston during Spraying Season

NASA Astrophysics Data System (ADS)

Usenko, S.; Clark, A. E.; Yoon, S.; Sheesley, R. J.

2015-12-01

It is a common practice for urban areas in the south to control the mosquito population through the routine spraying of pesticides utilizing ultra-low volume (ULV) foggers, either aerially or from trucks. Adult mosquitoes are known disease-borne vectors, including, but not limited to, West Nile Virus. Common mosquito adulticides include Permethrin (a pyrethroid) which is a neurotoxin. The EPA has labelled this pesticide good for mosquito treatment due to low cost, high effectiveness and low pest resistance. Permethrin is released directly into the atmosphere during active ULV fogger spraying, resulting in potentially significantly elevated atmospheric concentrations for hours to days after spray event. The metropolitan area of Houston, TX has a population of nearly 6 million people, making it the fourth most populous city in the U.S., and covers over 9000 square miles. During the DISCOVER-AQ sampling campaign in September 2013, nearly 300 atmospheric particular matter samples were collected during the month-long sampling campaign at four different locations in the Houston metropolitan area. Both total suspended particle (TSP) and particulate matter less than 2.5 microns in aerodynamic diameter (PM2.5) samples were collected, the latter of which is more readily inhaled and presents a greater risk to human health. Harris County, the main county of the Houston metropolitan area, controls mosquito for ~4-7 months, annually, covering the summer months. During 2013, Harris County utilized Permethrin as one of two pesticides in a weekly rotation from April to October. Proposed daily ULV treatment plans are published online on a neighborhood scale (Zip Code). Preliminary atmospheric concentrations show that Permethrin has been detected coinciding with days when treatment was proposed by the county. During or directly after use, atmospheric concentration of Permethrin were measuring at typically >10 ng m-3, but as high as 90 ng m-3. Atmospheric concentrations were also

Uncovering the Repertoire of Endogenous Flaviviral Elements in Aedes Mosquito Genomes

PubMed Central

Suzuki, Yasutsugu; Frangeul, Lionel; Dickson, Laura B.; Blanc, Hervé; Verdier, Yann; Vinh, Joelle

2017-01-01

ABSTRACT Endogenous viral elements derived from nonretroviral RNA viruses have been described in various animal genomes. Whether they have a biological function, such as host immune protection against related viruses, is a field of intense study. Here, we investigated the repertoire of endogenous flaviviral elements (EFVEs) in Aedes mosquitoes, the vectors of arboviruses such as dengue and chikungunya viruses. Previous studies identified three EFVEs from Aedes albopictus cell lines and one from Aedes aegypti cell lines. However, an in-depth characterization of EFVEs in wild-type mosquito populations and individual mosquitoes in vivo has not been performed. We detected the full-length DNA sequence of the previously described EFVEs and their respective transcripts in several A. albopictus and A. aegypti populations from geographically distinct areas. However, EFVE-derived proteins were not detected by mass spectrometry. Using deep sequencing, we detected the production of PIWI-interacting RNA-like small RNAs, in an antisense orientation, targeting the EFVEs and their flanking regions in vivo. The EFVEs were integrated in repetitive regions of the mosquito genomes, and their flanking sequences varied among mosquito populations. We bioinformatically predicted several new EFVEs from a Vietnamese A. albopictus population and observed variation in the occurrence of those elements among mosquitoes. Phylogenetic analysis of an A. aegypti EFVE suggested that it integrated prior to the global expansion of the species and subsequently diverged among and within populations. The findings of this study together reveal the substantial structural and nucleotide diversity of flaviviral integrations in Aedes genomes. Unraveling this diversity will help to elucidate the potential biological function of these EFVEs. IMPORTANCE Endogenous viral elements (EVEs) are whole or partial viral sequences integrated in host genomes. Interestingly, some EVEs have important functions for host

Uncovering the Repertoire of Endogenous Flaviviral Elements in Aedes Mosquito Genomes.

PubMed

Suzuki, Yasutsugu; Frangeul, Lionel; Dickson, Laura B; Blanc, Hervé; Verdier, Yann; Vinh, Joelle; Lambrechts, Louis; Saleh, Maria-Carla

2017-08-01

Endogenous viral elements derived from nonretroviral RNA viruses have been described in various animal genomes. Whether they have a biological function, such as host immune protection against related viruses, is a field of intense study. Here, we investigated the repertoire of endogenous flaviviral elements (EFVEs) in Aedes mosquitoes, the vectors of arboviruses such as dengue and chikungunya viruses. Previous studies identified three EFVEs from Aedes albopictus cell lines and one from Aedes aegypti cell lines. However, an in-depth characterization of EFVEs in wild-type mosquito populations and individual mosquitoes in vivo has not been performed. We detected the full-length DNA sequence of the previously described EFVEs and their respective transcripts in several A. albopictus and A. aegypti populations from geographically distinct areas. However, EFVE-derived proteins were not detected by mass spectrometry. Using deep sequencing, we detected the production of PIWI-interacting RNA-like small RNAs, in an antisense orientation, targeting the EFVEs and their flanking regions in vivo The EFVEs were integrated in repetitive regions of the mosquito genomes, and their flanking sequences varied among mosquito populations. We bioinformatically predicted several new EFVEs from a Vietnamese A. albopictus population and observed variation in the occurrence of those elements among mosquitoes. Phylogenetic analysis of an A. aegypti EFVE suggested that it integrated prior to the global expansion of the species and subsequently diverged among and within populations. The findings of this study together reveal the substantial structural and nucleotide diversity of flaviviral integrations in Aedes genomes. Unraveling this diversity will help to elucidate the potential biological function of these EFVEs. IMPORTANCE Endogenous viral elements (EVEs) are whole or partial viral sequences integrated in host genomes. Interestingly, some EVEs have important functions for host fitness and

Multiple Resistances and Complex Mechanisms of Anopheles sinensis Mosquito: A Major Obstacle to Mosquito-Borne Diseases Control and Elimination in China

PubMed Central

Fang, Qiang; Hartsel, Joshua; Zhou, Guofa; Shi, Linna; Fang, Fujin; Zhu, Changliang; Yan, Guiyun

2014-01-01

Malaria, dengue fever, and filariasis are three of the most common mosquito-borne diseases worldwide. Malaria and lymphatic filariasis can occur as concomitant human infections while also sharing common mosquito vectors. The overall prevalence and health significance of malaria and filariasis have made them top priorities for global elimination and control programmes. Pyrethroid resistance in anopheline mosquito vectors represents a highly significant problem to malaria control worldwide. Several methods have been proposed to mitigate insecticide resistance, including rotational use of insecticides with different modes of action. Anopheles sinensis, an important malaria and filariasis vector in Southeast Asia, represents an interesting mosquito species for examining the consequences of long-term insecticide rotation use on resistance. We examined insecticide resistance in two An. Sinensis populations from central and southern China against pyrethroids, organochlorines, organophosphates, and carbamates, which are the major classes of insecticides recommended for indoor residual spray. We found that the mosquito populations were highly resistant to the four classes of insecticides. High frequency of kdr mutation was revealed in the central population, whereas no kdr mutation was detected in the southern population. The frequency of G119S mutation in the ace-1 gene was moderate in both populations. The classification and regression trees (CART) statistical analysis found that metabolic detoxification was the most important resistance mechanism, whereas target site insensitivity of L1014 kdr mutation played a less important role. Our results indicate that metabolic detoxification was the dominant mechanism of resistance compared to target site insensitivity, and suggests that long-term rotational use of various insecticides has led An. sinensis to evolve a high insecticide resistance. This study highlights the complex network of mechanisms conferring multiple

Molecular survey of Dirofilaria immitis and Dirofilaria repens by direct PCR for wild caught mosquitoes in the Republic of Korea.

PubMed

Lee, Sang-Eun; Kim, Heung-Chul; Chong, Sung-Tae; Klein, Terry A; Lee, Won-Ja

2007-09-01

Adult mosquito collections using New Jersey light traps and Black-hole light traps were conducted to determine the potential vectors and the relative mosquito infection rates of Dirofilaria immitis and Dirofilaria repens in Gyeonggi and Gangwon Provinces, Republic of Korea, 2005. Dirofilaria spp. were confirmed by polymerase chain reaction (PCR) using species-specific primers for D. immitis and D. repens. Minimum field infection rates (MFIR) [MFIR = (number infected pools/total number of mosquitoes) x 1000] of 12 pools/2059 total number mosquitoes (5.8) and 21 pools (10.1) of the wild caught mosquitoes were positive by PCR for D. immitis and D. repens, respectively. Dual infections of both D. immitis and D. repens were detected by PCR in eight pools (3.9). Anopheles sinensis sensu lato (includes An. sinensis s.s., An. pullus, An. kleini, An. belenrae, and An. lesteri), An. sineroides, Aedes vexans nipponi, Culex pipiens and Armigeres subalbatus were found to be infected and are potential vectors of D. immitis and D. repens in Korea. Infections observed in mosquitoes represent potential health risks for domestic animal and human populations.

Dynamics of West Nile virus evolution in mosquito vectors.

PubMed

Grubaugh, Nathan D; Ebel, Gregory D

2016-12-01

West Nile virus remains the most common cause of arboviral encephalitis in North America. Since it was introduced, it has undergone adaptive genetic change as it spread throughout the continent. The WNV transmission cycle is relatively tractable in the laboratory. Thus the virus serves as a convenient model system for studying the population biology of mosquito-borne flaviviruses as they undergo transmission to and from mosquitoes and vertebrates. This review summarizes the current knowledge regarding the population dynamics of this virus within mosquito vectors. Copyright © 2016 Elsevier B.V. All rights reserved.

Spinosad: a biorational mosquito larvicide for use in car tires in southern Mexico

PubMed Central

2012-01-01

Background Car tires are important habitats for mosquito development because of the high density populations they can harbor and their presence in urban settings. Water in experimental tires was treated with one of three insecticides or an untreated control. Aquatic invertebrates were sampled at weekly intervals. Eggs, larval and pupal samples were laboratory-reared to estimate seasonal fluctuations in Aedes aegypti and Ae. albopictus abundance. Results Spinosad treatments at 1 or 5 ppm (mg a.i./liter) provided 6–8 weeks of effective control of Ae. aegypti, Ae. albopictus, Culex quinquefasiatus and Cx. coronator larvae, both in the dry season and the rainy season when mosquito populations increased markedly in southern Mexico. Spinosad continued to provide partial control of larvae for several weeks after initial recolonization of treated tires. The larvicidal performance of VectoBac 12AS (Bacillus thuringiensis var. israelensis) was relatively poor with one week of complete control of Aedes spp. larvae and no discernible control of Culex spp., whereas the duration of larvicidal activity of 1% temephos mineral-based granules was intermediate between those of VectoBac and spinosad treatments. Populations of chironomids, ostracods and Toxorhynchites theobaldi were generally reduced in spinosad and temephos treatments, but were similar in control and VectoBac treatments. Conclusion The present study is the first to report spinosad as an effective larvicide against Cx. coronator, which is currently invading the southern United States. These results substantiate the use of spinosad as a highly effective mosquito larvicide, even in habitats such as unused car tires that can represent prolific sources of adult mosquitoes. PMID:22608138

Evaluating the effects of mosquito control adulticides on honey bees

USDA-ARS?s Scientific Manuscript database

While mosquito control adulticides can be effective in rapidly reducing mosquito populations during times of high arbovirus transmission, the impacts of these control measures on pollinators has been of recent interest. The purpose of our study was to evaluate mosquito and honey bee mortality using ...

Ecological distribution and population dynamics of Rift Valley fever virus mosquito vectors (Diptera, Culicidae) in Senegal.

PubMed

Biteye, Biram; Fall, Assane G; Ciss, Mamadou; Seck, Momar T; Apolloni, Andrea; Fall, Moussa; Tran, Annelise; Gimonneau, Geoffrey

2018-01-09

Many zoonotic infectious diseases have emerged and re-emerged over the last two decades. There has been a significant increase in vector-borne diseases due to climate variations that lead to environmental changes favoring the development and adaptation of vectors. This study was carried out to improve knowledge of the ecology of mosquito vectors involved in the transmission of Rift Valley fever virus (RVFV) in Senegal. An entomological survey was conducted in three Senegalese agro-systems, Senegal River Delta (SRD), Senegal River Valley (SRV) and Ferlo, during the rainy season (July to November) of 2014 and 2015. Mosquitoes were trapped using CDC light traps set at ten sites for two consecutive nights during each month of the rainy season, for a total of 200 night-traps. Ecological indices were calculated to characterize the different populations of RVFV mosquito vectors. Generalized linear models with mixed effects were used to assess the influence of climatic conditions on the abundance of RVFV mosquito vectors. A total of 355,408 mosquitoes belonging to 7 genera and 35 species were captured in 200 night-traps. RVFV vectors represented 89.02% of the total, broken down as follows: Ae. vexans arabiensis (31.29%), Cx. poicilipes (0.6%), Cx. tritaeniorhynchus (33.09%) and Ma. uniformis (24.04%). Comparison of meteorological indices (rainfall, temperature, relative humidity), abundances and species diversity indicated that there were no significant differences between SRD and SRV (P = 0.36) while Ferlo showed significant differences with both (P < 0.001). Mosquito collection increased significantly with temperature for Ae. vexans arabiensis (P < 0.001), Cx. tritaeniorhynchus (P = 0.04) and Ma. uniformis (P = 0.01), while Cx. poicilipes decreased (P = 0.003). Relative humidity was positively and significantly associated with the abundances of Ae. vexans arabiensis (P < 0.001), Cx. poicilipes (P = 0.01) and Cx. tritaeniorhynchus (P�

Relevant microclimate for determining the development rate of malaria mosquitoes and possible implications of climate change.

PubMed

Paaijmans, Krijn P; Imbahale, Susan S; Thomas, Matthew B; Takken, Willem

2010-07-09

The relationship between mosquito development and temperature is one of the keys to understanding the current and future dynamics and distribution of vector-borne diseases such as malaria. Many process-based models use mean air temperature to estimate larval development times, and hence adult vector densities and/or malaria risk. Water temperatures in three different-sized water pools, as well as the adjacent air temperature in lowland and highland sites in western Kenya were monitored. Both air and water temperatures were fed into a widely-applied temperature-dependent development model for Anopheles gambiae immatures, and subsequently their impact on predicted vector abundance was assessed. Mean water temperature in typical mosquito breeding sites was 4-6 degrees C higher than the mean temperature of the adjacent air, resulting in larval development rates, and hence population growth rates, that are much higher than predicted based on air temperature. On the other hand, due to the non-linearities in the relationship between temperature and larval development rate, together with a marginal buffering in the increase in water temperature compared with air temperature, the relative increases in larval development rates predicted due to climate change are substantially less. Existing models will tend to underestimate mosquito population growth under current conditions, and may overestimate relative increases in population growth under future climate change. These results highlight the need for better integration of biological and environmental information at the scale relevant to mosquito biology.

How does the dengue vector mosquito Aedes albopictus respond to global warming?

PubMed

Jia, Pengfei; Chen, Xiang; Chen, Jin; Lu, Liang; Liu, Qiyong; Tan, Xiaoyue

2017-03-11

Global warming has a marked influence on the life cycle of epidemic vectors as well as their interactions with human beings. The Aedes albopictus mosquito as the vector of dengue fever surged exponentially in the last decade, raising ecological and epistemological concerns of how climate change altered its growth rate and population dynamics. As the global warming pattern is considerably uneven across four seasons, with a confirmed stronger effect in winter, an emerging need arises as to exploring how the seasonal warming effects influence the annual development of Ae. albopictus. The model consolidates a 35-year climate dataset and designs fifteen warming patterns that increase the temperature of selected seasons. Based on a recently developed mechanistic population model of Ae. albopictus, the model simulates the thermal reaction of blood-fed adults by systematically increasing the temperature from 0.5 to 5 °C at an interval of 0.5 °C in each warming pattern. The results show the warming effects are different across seasons. The warming effects in spring and winter facilitate the development of the species by shortening the diapause period. The warming effect in summer is primarily negative by inhibiting mosquito development. The warming effect in autumn is considerably mixed. However, these warming effects cannot carry over to the following year, possibly due to the fact that under the extreme weather in winter the mosquito fully ceases from development and survives in terms of diapause eggs. As the historical pattern of global warming manifests seasonal fluctuations, this study provides corroborating and previously ignored evidence of how such seasonality affects the mosquito development. Understanding this short-term temperature-driven mechanism as one chain of the transmission events is critical to refining the thermal reaction norms of the epidemic vector under global warming as well as developing effective mosquito prevention and control strategies.

Climatic Factors Driving Invasion of the Tiger Mosquito (Aedes albopictus) into New Areas of Trentino, Northern Italy

PubMed Central

Castellani, Cristina; Arnoldi, Daniele; Rizzoli, Annapaola

2011-01-01

Background The tiger mosquito (Aedes albopictus), vector of several emerging diseases, is expanding into more northerly latitudes as well as into higher altitudes in northern Italy. Changes in the pattern of distribution of the tiger mosquito may affect the potential spread of infectious diseases transmitted by this species in Europe. Therefore, predicting suitable areas of future establishment and spread is essential for planning early prevention and control strategies. Methodology/Principal Findings To identify the areas currently most suitable for the occurrence of the tiger mosquito in the Province of Trento, we combined field entomological observations with analyses of satellite temperature data (MODIS Land Surface Temperature: LST) and human population data. We determine threshold conditions for the survival of overwintering eggs and for adult survival using both January mean temperatures and annual mean temperatures. We show that the 0°C LST threshold for January mean temperatures and the 11°C threshold for annual mean temperatures provide the best predictors for identifying the areas that could potentially support populations of this mosquito. In fact, human population density and distance to human settlements appear to be less important variables affecting mosquito distribution in this area. Finally, we evaluated the future establishment and spread of this species in relation to predicted climate warming by considering the A2 scenario for 2050 statistically downscaled at regional level in which winter and annual temperatures increase by 1.5 and 1°C, respectively. Conclusions/Significance MODIS satellite LST data are useful for accurately predicting potential areas of tiger mosquito distribution and for revealing the range limits of this species in mountainous areas, predictions which could be extended to an European scale. We show that the observed trend of increasing temperatures due to climate change could facilitate further invasion of Ae. albopictus

Transmission of tularemia from a water source by transstadial maintenance in a mosquito vector

NASA Astrophysics Data System (ADS)

Bäckman, Stina; Näslund, Jonas; Forsman, Mats; Thelaus, Johanna

2015-01-01

Mosquitoes are thought to function as mechanical vectors of Francisella tularensis subspecies holarctica (F. t. holarctica) causing tularemia in humans. We investigated the clinical relevance of transstadially maintained F. t. holarctica in mosquitoes. Aedes egypti larvae exposed to a fully virulent F. t. holarctica strain for 24 hours, were allowed to develop into adults when they were individually homogenized. Approximately 24% of the homogenates tested positive for F. t. DNA in PCR. Mice injected with the mosquito homogenates acquired tularemia within 5 days. This novel finding demonstrates the possibility of transmission of bacteria by adult mosquitoes having acquired the pathogen from their aquatic larval habitats.

Dispersal of adult culex mosquitoes in an urban west nile virus hotspot: a mark-capture study incorporating stable isotope enrichment of natural larval habitats.

PubMed

Hamer, Gabriel L; Anderson, Tavis K; Donovan, Danielle J; Brawn, Jeffrey D; Krebs, Bethany L; Gardner, Allison M; Ruiz, Marilyn O; Brown, William M; Kitron, Uriel D; Newman, Christina M; Goldberg, Tony L; Walker, Edward D

2014-03-01

Dispersal is a critical life history behavior for mosquitoes and is important for the spread of mosquito-borne disease. We implemented the first stable isotope mark-capture study to measure mosquito dispersal, focusing on Culex pipiens in southwest suburban Chicago, Illinois, a hotspot of West Nile virus (WNV) transmission. We enriched nine catch basins in 2010 and 2011 with 15N-potassium nitrate and detected dispersal of enriched adult females emerging from these catch basins using CDC light and gravid traps to distances as far as 3 km. We detected 12 isotopically enriched pools of mosquitoes out of 2,442 tested during the two years and calculated a mean dispersal distance of 1.15 km and maximum flight range of 2.48 km. According to a logistic distribution function, 90% of the female Culex mosquitoes stayed within 3 km of their larval habitat, which corresponds with the distance-limited genetic variation of WNV observed in this study region. This study provides new insights on the dispersal of the most important vector of WNV in the eastern United States and demonstrates the utility of stable isotope enrichment for studying the biology of mosquitoes in other disease systems.

Detection of all four dengue serotypes in Aedes aegypti female mosquitoes collected in a rural area in Colombia

PubMed Central

Pérez-Castro, Rosalía; Castellanos, Jaime E; Olano, Víctor A; Matiz, María Inés; Jaramillo, Juan F; Vargas, Sandra L; Sarmiento, Diana M; Stenström, Thor Axel; Overgaard, Hans J

2016-01-01

The Aedes aegypti vector for dengue virus (DENV) has been reported in urban and periurban areas. The information about DENV circulation in mosquitoes in Colombian rural areas is limited, so we aimed to evaluate the presence of DENV in Ae. aegypti females caught in rural locations of two Colombian municipalities, Anapoima and La Mesa. Mosquitoes from 497 rural households in 44 different rural settlements were collected. Pools of about 20 Ae. aegypti females were processed for DENV serotype detection. DENV in mosquitoes was detected in 74% of the analysed settlements with a pool positivity rate of 62%. The estimated individual mosquito infection rate was 4.12% and the minimum infection rate was 33.3/1,000 mosquitoes. All four serotypes were detected; the most frequent being DENV-2 (50%) and DENV-1 (35%). Two-three serotypes were detected simultaneously in separate pools. This is the first report on the co-occurrence of natural DENV infection of mosquitoes in Colombian rural areas. The findings are important for understanding dengue transmission and planning control strategies. A potential latent virus reservoir in rural areas could spill over to urban areas during population movements. Detecting DENV in wild-caught adult mosquitoes should be included in the development of dengue epidemic forecasting models. PMID:27074252

Detection of all four dengue serotypes in Aedes aegypti female mosquitoes collected in a rural area in Colombia.

PubMed

Pérez-Castro, Rosalía; Castellanos, Jaime E; Olano, Víctor A; Matiz, María Inés; Jaramillo, Juan F; Vargas, Sandra L; Sarmiento, Diana M; Stenström, Thor Axel; Overgaard, Hans J

2016-04-01

The Aedes aegypti vector for dengue virus (DENV) has been reported in urban and periurban areas. The information about DENV circulation in mosquitoes in Colombian rural areas is limited, so we aimed to evaluate the presence of DENV in Ae. aegypti females caught in rural locations of two Colombian municipalities, Anapoima and La Mesa. Mosquitoes from 497 rural households in 44 different rural settlements were collected. Pools of about 20 Ae. aegypti females were processed for DENV serotype detection. DENV in mosquitoes was detected in 74% of the analysed settlements with a pool positivity rate of 62%. The estimated individual mosquito infection rate was 4.12% and the minimum infection rate was 33.3/1,000 mosquitoes. All four serotypes were detected; the most frequent being DENV-2 (50%) and DENV-1 (35%). Two-three serotypes were detected simultaneously in separate pools. This is the first report on the co-occurrence of natural DENV infection of mosquitoes in Colombian rural areas. The findings are important for understanding dengue transmission and planning control strategies. A potential latent virus reservoir in rural areas could spill over to urban areas during population movements. Detecting DENV in wild-caught adult mosquitoes should be included in the development of dengue epidemic forecasting models.

Reduction of mosquito biting-pressure: spatial repellents or mosquito traps? A field comparison of seven commercially available products in Israel

USDA-ARS?s Scientific Manuscript database

The personal protection capability of seven commercially available mosquito control devices (MCD) is compared under field conditions in Israel. Trials were performed in a high biting-pressure area inhabited by large populations of mosquito and biting midge species and using human volunteers for lan...

Comparisons of mosquito populations before and after construction of a wetland for water quality improvement in Pitt County, North Carolina, and data-reliant vectorborne disease management.

PubMed

Anderson, Alice L; O'Brien, Kevin; Hartwell, Megan

2007-04-01

Wetlands serve an important purpose in flood control and water quality, but constructed-wetland sites also provide habitats for mosquito breeding. Communities near constructed-wetland sites often raise a "mosquito" objection when constructed wetlands are proposed. Wildlife and wetland advocates can confuse the public by making unsubstantiated claims about natural predators eliminating or controlling mosquito problems in a constructed wetland. Management of constructed-wetland mosquito habitat, with adequate mosquito surveillance and data analysis, can help lead to a successful project and satisfied citizens. The cooperative project described in this paper, was conducted in the town of Simpson, North Carolina, and was designed to determine the mosquito population impact of wetland construction at Mill Branch Stream, a small tributary of the Tar River in Eastern North Carolina. In the authors' analysis of three years of mosquito surveillance data, month (time of year standing in for temperature and day length) was a significant factor in regression analysis for mosquito numbers, but rainfall was not. Numbers of mosquitoes were not found to be significantly higher after construction than before construction.

Immune reactivity to dengue and Aedes albopictus mosquitoes in the population from Macao, China, before dengue occurrence.

PubMed

De Carvalho, Isabel Lopes; Rocha, Diara Kady; Almeida, A Paulo G

2011-01-01

A serological survey was conducted in Macao, China, in 753 individuals, with the objective of looking for antibodies to the mosquito, Aedes albopictus (Skuse 1894) (Diptera: Culicidae), and to dengue, before the occurrence of any autochthonous dengue cases. Blood samples were collected at several public health services, a questionnaire was answered, and enzyme-linked immunosorbant assay (ELISA) and Western blot techniques were performed with extracts of mosquito head and thorax (HT). Anti-Aedes albopictus IgG antibodies were present in titres 1:10(2)-1:10(3) in 9%, and in titres 1:10(4)-1:10(5) in 42% of the sera tested. This reactivity was more frequent (59%) in the population which had resided only in Macao in the 2 years previous to the survey, as opposed to those that had also resided in other areas (50%). From the 230 reactive sera selected for immunoblot, 48 (21%) reacted with a wide range of proteins from above 224 kDa to 21 kDa, with different patterns according to individual sera. Proteins in the intervals 35.3-28.7 kDa and 28.7-21.1 kDa were labelled by the greatest number of sera, 15 and 19 respectively. The presence of anti-Aedes albopictus antibodies presented a statistical relation to skin reaction to mosquito bites, but immunoblot patterns did not. Anti-dengue IgG antibodies were found in 48% of the subjects, with a higher proportion in people who had resided out of Macao, or who were nationals from dengue-endemic neighboring countries. Anti-dengue reactivity was in agreement with anti-mosquito reactivity in half of the population. It would be interesting to see if this proportion has changed since dengue became endemic in Macao in 2001.

Citizen Science as a Tool for Mosquito Control.

PubMed

Jordan, Rebecca C; Sorensen, Amanda E; Ladeau, Shannon

2017-09-01

In this paper, we share our findings from a 2-year citizen science program called Mosquito Stoppers. This pest-oriented citizen science project is part of a larger coupled natural-human systems project seeking to understand the fundamental drivers of mosquito population density and spatial variability in potential exposure to mosquito-borne pathogens in a matrix of human construction, urban renewal, and individual behaviors. Focusing on residents in West Baltimore, participants were recruited through neighborhood workshops and festivals. Citizen scientists participated in yard surveys of potential mosquito habitat and in evaluating mosquito nuisance. We found that citizen scientists, with minimal education and training, were able to accurately collect data that reflect trends found in a comparable researcher-generated database.

Assessing the impacts of truck based ultra-low volume applications of mosquito adulticides on honey bees (Apis mellifera)

USDA-ARS?s Scientific Manuscript database

Mosquito control reduces populations of mosquitoes to minimize the risk of mosquito-borne diseases. As part of an integrated approach to mosquito control, application of adulticides can be effective in rapidly reducing mosquito populations during times of high arbovirus transmission. However, impact...

A Field Study in Benin to Investigate the Role of Mosquitoes and Other Flying Insects in the Ecology of Mycobacterium ulcerans

PubMed Central

Zogo, Barnabas; Djenontin, Armel; Carolan, Kevin; Babonneau, Jeremy; Guegan, Jean-François; Eyangoh, Sara; Marion, Estelle

2015-01-01

Background Buruli ulcer, the third mycobacterial disease after tuberculosis and leprosy, is caused by the environmental mycobacterium M. ulcerans. There is at present no clear understanding of the exact mode(s) of transmission of M. ulcerans. Populations affected by Buruli ulcer are those living close to humid and swampy zones. The disease is associated with the creation or the extension of swampy areas, such as construction of dams or lakes for the development of agriculture. Currently, it is supposed that insects (water bugs and mosquitoes) are host and vector of M. ulcerans. The role of water bugs was clearly demonstrated by several experimental and environmental studies. However, no definitive conclusion can yet be drawn concerning the precise importance of this route of transmission. Concerning the mosquitoes, DNA was detected only in mosquitoes collected in Australia, and their role as host/vector was never studied by experimental approaches. Surprisingly, no specific study was conducted in Africa. In this context, the objective of this study was to investigate the role of mosquitoes (larvae and adults) and other flying insects in ecology of M. ulcerans. This study was conducted in a highly endemic area of Benin. Methodology/Principal Findings Mosquitoes (adults and larvae) were collected over one year, in Buruli ulcer endemic in Benin. In parallel, to monitor the presence of M. ulcerans in environment, aquatic insects were sampled. QPCR was used to detected M. ulcerans DNA. DNA of M. ulcerans was detected in around 8.7% of aquatic insects but never in mosquitoes (larvae or adults) or in other flying insects. Conclusion/Significance This study suggested that the mosquitoes don't play a pivotal role in the ecology and transmission of M. ulcerans in the studied endemic areas. However, the role of mosquitoes cannot be excluded and, we can reasonably suppose that several routes of transmission of M. ulcerans are possible through the world. PMID:26196901

Biological Control Strategies for Mosquito Vectors of Arboviruses.

PubMed

Huang, Yan-Jang S; Higgs, Stephen; Vanlandingham, Dana L

2017-02-10

Historically, biological control utilizes predatory species and pathogenic microorganisms to reduce the population of mosquitoes as disease vectors. This is particularly important for the control of mosquito-borne arboviruses, which normally do not have specific antiviral therapies available. Although development of resistance is likely, the advantages of biological control are that the resources used are typically biodegradable and ecologically friendly. Over the past decade, the advancement of molecular biology has enabled optimization by the manipulation of genetic materials associated with biological control agents. Two significant advancements are the discovery of cytoplasmic incompatibility induced by Wolbachia bacteria, which has enhanced replacement programs, and the introduction of dominant lethal genes into local mosquito populations through the release of genetically modified mosquitoes. As various arboviruses continue to be significant public health threats, biological control strategies have evolved to be more diverse and become critical tools to reduce the disease burden of arboviruses.

Biological Control Strategies for Mosquito Vectors of Arboviruses

PubMed Central

Huang, Yan-Jang S.; Higgs, Stephen; Vanlandingham, Dana L.

2017-01-01

Historically, biological control utilizes predatory species and pathogenic microorganisms to reduce the population of mosquitoes as disease vectors. This is particularly important for the control of mosquito-borne arboviruses, which normally do not have specific antiviral therapies available. Although development of resistance is likely, the advantages of biological control are that the resources used are typically biodegradable and ecologically friendly. Over the past decade, the advancement of molecular biology has enabled optimization by the manipulation of genetic materials associated with biological control agents. Two significant advancements are the discovery of cytoplasmic incompatibility induced by Wolbachia bacteria, which has enhanced replacement programs, and the introduction of dominant lethal genes into local mosquito populations through the release of genetically modified mosquitoes. As various arboviruses continue to be significant public health threats, biological control strategies have evolved to be more diverse and become critical tools to reduce the disease burden of arboviruses. PMID:28208639

City-Dwellers and Country Folks: Lack of Population Differentiation Along an Urban-Rural Gradient in the Mosquito Culex pipiens (Diptera: Culicidae).

PubMed

Honnen, Ann-Christin; Monaghan, Michael T; Sharakhov, Igor

2017-09-01

Mosquitoes (Diptera, Culicidae) occur in natural, urban, and peri-urban areas throughout the globe. Although the characteristics of urban and peri-urban habitats differ from those of natural habitats in many ways (e.g., fragmentation, pollution, noise, and light), few studies have examined the population connectivity of mosquitoes in urban areas. To obtain an overview of the species composition, we sampled mosquitoes from 23 sites in and around the city of Berlin, Germany. Of 23 species, five occurred in urban, 10 in peri-urban, and 20 in rural areas. Culex pipiens Linnaeus (Diptera: Culicidae) was the most common species collected (75% of all individuals) and occurred in all habitats. Hence this species was selected to be analysed at 10 microsatellite markers. There was no significant differentiation (FST = 0.016, P = 0.9) or isolation by distance (P = 0.06) among Cx. pipiens populations along an urban-rural gradient. The only significant differences detected were between Cx. pipiens and a laboratory population of Cx. pipiens f. molestus (pairwise FST = 0.114-0.148, P ≤ 0.001 in all comparisons), suggesting that the markers chosen were suitable for the identification of population differentiation. Our results indicate that Cx. pipiens gene flow is widespread within and among urban, peri-urban, and rural areas and that urban habitat does not necessarily impede or enhance gene flow among these populations. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

Diverse Dengue Type 2 Virus Populations Contain Recombinant and Both Parental Viruses in a Single Mosquito Host

PubMed Central

Craig, Scott; Thu, Hlaing Myat; Lowry, Kym; Wang, Xiao-fang; Holmes, Edward C.; Aaskov, John

2003-01-01

Envelope (E) protein genes sampled from populations of dengue 2 (DEN-2) virus in individual Aedes aegypti mosquitoes and in serum from dengue patients were copied to cDNA, cloned, and sequenced. The nucleotide sequences of the E genes in more than 70% of the clones differed from the consensus sequence for the corresponding virus population at up to 11 sites, and 24 of the 94 clones contained at least one stop codon. Virus populations recovered up to 2 years apart yielded clones with similar polymorphisms in the E gene. For one mosquito, the clones obtained fell into two genotypes. One group of sequences was closely related to those of viruses recovered from dengue patients in the same locality (Yangon, Myanmar) since 1995 and were classified as Asian 1 genotype. The second group were Cosmopolitan genotype viruses which were also circulating in Yangon in 2000 and which were related to DEN-2 viruses sampled from southern China in 1999. Finally, one clone was identified as a recombinant genome composed of portions of these two “parental” genotypes. This is the first report of recombinant and parental dengue viruses in a single host. PMID:12634407

Bacterial microbiota assemblage in Aedes albopictus mosquitoes and its impacts on larval development.

PubMed

Wang, Xiaoming; Liu, Tong; Wu, Yang; Zhong, Daibin; Zhou, Guofa; Su, Xinghua; Xu, Jiabao; Sotero, Charity F; Sadruddin, Adnan A; Wu, Kun; Chen, Xiao-Guang; Yan, Guiyun

2018-05-30

Interactions between bacterial microbiota and mosquitoes play an important role in mosquitoes' capacity to transmit pathogens. However, microbiota assemblages within mosquitoes and the impact of microbiota in environments on mosquito development and survival remain unclear. This study examined microbiota assemblages and the effects of aquatic environment microbiota on the larval development of the Aedes albopictus mosquito, an important dengue virus vector. Life table studies have found that reducing bacterial load in natural aquatic habitats through water filtering and treatment with antibiotics significantly reduced the larva-to-adult emergence rate. This finding was consistent in two types of larval habitats examined-discarded tires and flowerpots, suggesting that bacteria play a crucial role in larval development. Pyrosequencing of the bacterial 16S rRNA gene was used to determine the diversity of bacterial communities in larval habitats and the resulting numbers of mosquitoes under both laboratory and field conditions. The microbiota profiling identified common shared bacteria among samples from different years; further studies are needed to determine whether these bacteria represent a core microbiota. The highest microbiota diversity was found in aquatic habitats, followed by mosquito larvae, and the lowest in adult mosquitoes. Mosquito larvae ingested their bacterial microbiota and nutrients from aquatic habitats of high microbiota diversity. Taken together, the results support the observation that Ae. albopictus larvae are able to utilize diverse bacteria from aquatic habitats and that live bacteria from aquatic habitats play an important role in larval mosquito development and survival. These findings provide new insights into bacteria's role in mosquito larval ecology. © 2018 John Wiley & Sons Ltd.

What does not kill them makes them stronger: larval environment and infectious dose alter mosquito potential to transmit filarial worms.

PubMed

Breaux, Jennifer A; Schumacher, Molly K; Juliano, Steven A

2014-07-07

For organisms with complex life cycles, larval environments can modify adult phenotypes. For mosquitoes and other vectors, when physiological impacts of stressors acting on larvae carry over into the adult stage they may interact with infectious dose of a vector-borne pathogen, producing a range of phenotypes for vector potential. Investigation of impacts of a common source of stress, larval crowding and intraspecific competition, on adult vector interactions with pathogens may increase our understanding of the dynamics of pathogen transmission by mosquito vectors. Using Aedes aegypti and the nematode parasite Brugia pahangi, we demonstrate dose dependency of fitness effects of B. pahangi infection on the mosquito, as well as interactions between competitive stress among larvae and infectious dose for resulting adults that affect the physiological and functional ability of mosquitoes to act as vectors. Contrary to results from studies on mosquito-arbovirus interactions, our results suggest that adults from crowded larvae may limit infection better than do adults from uncrowded controls, and that mosquitoes from high-quality larval environments are more physiologically and functionally capable vectors of B. pahangi. Our results provide another example of how the larval environment can have profound effects on vector potential of resulting adults. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Aerial ULV application of permethrin against adult mosquitoes over open field and medium density canopy habitat in a hot-temperate zone

USDA-ARS?s Scientific Manuscript database

Although aerial ULV application of adulticides is a common adult mosquito control strategy, not enough is known about the fate of the pesticide or its efficacy over different habitats. Dye labeling of droplets is used to evaluate ULV applications, and, by inference, their efficacy. Placement of cage...

Carryover effects of larval exposure to different environmental bacteria drive adult trait variation in a mosquito vector

PubMed Central

Dickson, Laura B.; Jiolle, Davy; Minard, Guillaume; Moltini-Conclois, Isabelle; Volant, Stevenn; Ghozlane, Amine; Bouchier, Christiane; Ayala, Diego; Paupy, Christophe; Moro, Claire Valiente; Lambrechts, Louis

2017-01-01

Conditions experienced during larval development of holometabolous insects can affect adult traits, but whether differences in the bacterial communities of larval development sites contribute to variation in the ability of insect vectors to transmit human pathogens is unknown. We addressed this question in the mosquito Aedes aegypti, a major arbovirus vector breeding in both sylvatic and domestic habitats in Sub-Saharan Africa. Targeted metagenomics revealed differing bacterial communities in the water of natural breeding sites in Gabon. Experimental exposure to different native bacterial isolates during larval development resulted in significant differences in pupation rate and adult body size but not life span. Larval exposure to an Enterobacteriaceae isolate resulted in decreased antibacterial activity in adult hemolymph and reduced dengue virus dissemination titer. Together, these data provide the proof of concept that larval exposure to different bacteria can drive variation in adult traits underlying vectorial capacity. Our study establishes a functional link between larval ecology, environmental microbes, and adult phenotypic variation in a holometabolous insect vector. PMID:28835919

Newly discovered population of Aedes japonicus japonicus (Diptera: Culicidae) in Upper Bavaria, Germany, and Salzburg, Austria, is closely related to the Austrian/Slovenian bush mosquito population.

PubMed

Zielke, Dorothee E; Walther, Doreen; Kampen, Helge

2016-03-21

The German mosquito surveillance instrument 'Mueckenatlas' requests the general public to collect and submit mosquito specimens. Among these, increasing numbers of individuals of invasive species have been registered. Specimens of the Asian bush mosquito Aedes japonicus japonicus submitted from German Upper Bavaria, where this species had not previously been recorded, triggered regional monitoring in mid-2015. The search for Ae. j. japonicus breeding sites and developmental stages concentrated on cemeteries in the municipality of origin of the submitted specimens and, subsequently, in the whole region. A virtual grid consisting of 10 × 10 km(2) cells in which up to three cemeteries were checked, was laid over the region. A cell was considered positive as soon as Ae. j. japonicus larvae were detected, and regarded negative when no larvae could be found in any of the cemeteries inspected. All cells surrounding a positive cell were screened accordingly. A subset of collected Aedes j. japonicus specimens was subjected to microsatellite and nad4 sequence analyses, and obtained data were compared to individuals from previously discovered European populations. Based on the grid cells, an area of approximately 900 km(2) was populated by Ae. j. japonicus in Upper Bavaria and neighbouring Austria. Genetic analyses of microsatellites and nad4 gene sequences generated one genotype out of two previously described for Europe and three haplotypes, one of which had previously been found in Europe only in Ae. j. japonicus samples from a population in East Austria and Slovenia. The genetic analysis suggests the new population is closely related to the Austrian/Slovenian population. As Ae. j. japonicus is well adapted to temperate climates, it has a strong tendency to expand and to colonise new territories in Central Europe, which is facilitated by human-mediated, passive transportation. The new population in Upper Bavaria/Austria is the seventh separate population described in

Mosquito Consumption by Insectivorous Bats: Does Size Matter?

PubMed Central

Gonsalves, Leroy; Bicknell, Brian; Law, Brad; Webb, Cameron; Monamy, Vaughan

2013-01-01

Insectivorous bats have often been touted as biological control for mosquito populations. However, mosquitoes generally represent only a small proportion of bat diet. Given the small size of mosquitoes, restrictions imposed on prey detectability by low frequency echolocation, and variable field metabolic rates (FMR), mosquitoes may not be available to or profitable for all bats. This study investigated whether consumption of mosquitoes was influenced by bat size, which is negatively correlated with echolocation frequency but positively correlated with bat FMR. To assess this, we investigated diets of five eastern Australian bat species (Vespadelus vulturnus Thomas, V. pumilus Gray, Miniopterus australis Tomes, Nyctophilus gouldi Tomes and Chalinolobus gouldii Gray) ranging in size from 4-14 g in coastal forest, using molecular analysis of fecal DNA. Abundances of potential mosquito and non-mosquito prey were concurrently measured to provide data on relative prey abundance. Aedes vigilax was locally the most abundant mosquito species, while Lepidoptera the most abundant insect order. A diverse range of prey was detected in bat feces, although members of Lepidoptera dominated, reflecting relative abundance at trap sites. Consumption of mosquitoes was restricted to V. vulturnus and V. pumilus, two smaller sized bats (4 and 4.5 g). Although mosquitoes were not commonly detected in feces of V. pumilus, they were present in feces of 55 % of V. vulturnus individuals. To meet nightly FMR requirements, Vespadelus spp. would need to consume ~600-660 mosquitoes on a mosquito-only diet, or ~160-180 similar sized moths on a moth-only diet. Lower relative profitability of mosquitoes may provide an explanation for the low level of mosquito consumption among these bats and the absence of mosquitoes in feces of larger bats. Smaller sized bats, especially V. vulturnus, are likely to be those most sensitive to reductions in mosquito abundance and should be monitored during mosquito

Applications of a sugar-based surveillance system to track arboviruses in wild mosquito populations.

PubMed

van den Hurk, Andrew F; Hall-Mendelin, Sonja; Townsend, Michael; Kurucz, Nina; Edwards, Jim; Ehlers, Gerhard; Rodwell, Chris; Moore, Frederick A; McMahon, Jamie L; Northill, Judith A; Simmons, Russell J; Cortis, Giles; Melville, Lorna; Whelan, Peter I; Ritchie, Scott A

2014-01-01

Effective arbovirus surveillance is essential to ensure the implementation of control strategies, such as mosquito suppression, vaccination, or dissemination of public warnings. Traditional strategies employed for arbovirus surveillance, such as detection of virus or virus-specific antibodies in sentinel animals, or detection of virus in hematophagous arthropods, have limitations as an early-warning system. A system was recently developed that involves collecting mosquitoes in CO2-baited traps, where the insects expectorate virus on sugar-baited nucleic acid preservation cards. The cards are then submitted for virus detection using molecular assays. We report the application of this system for detecting flaviviruses and alphaviruses in wild mosquito populations in northern Australia. This study was the first to employ nonpowered passive box traps (PBTs) that were designed to house cards baited with honey as the sugar source. Overall, 20/144 (13.9%) of PBTs from different weeks contained at least one virus-positive card. West Nile virus Kunjin subtype (WNVKUN), Ross River virus (RRV), and Barmah Forest virus (BFV) were detected, being identified in 13/20, 5/20, and 2/20 of positive PBTs, respectively. Importantly, sentinel chickens deployed to detect flavivirus activity did not seroconvert at two Northern Territory sites where four PBTs yielded WNVKUN. Sufficient WNVKUN and RRV RNA was expectorated onto some of the honey-soaked cards to provide a template for gene sequencing, enhancing the utility of the sugar-bait surveillance system for investigating the ecology, emergence, and movement of arboviruses.

Mosquito Control

MedlinePlus

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A natural agonist of mosquito TRPA1 from the medicinal plant Cinnamosma fragrans that is toxic, antifeedant, and repellent to the yellow fever mosquito Aedes aegypti.

PubMed

Inocente, Edna Alfaro; Shaya, Marguerite; Acosta, Nuris; Rakotondraibe, L Harinantenaina; Piermarini, Peter M

2018-02-01

Plants produce various secondary metabolites that offer a potential source of novel insecticides and repellents for the control of mosquito vectors. Plants of the genus Cinnamosma are endemic to, and widely-distributed throughout, the island of Madagascar. The barks of these species are commonly used in traditional medicines for treating a wide range of maladies. The therapeutic nature of the bark is thought to be associated with its enrichment of pungent drimane sesquiterpenes, which elicit antifeedant and toxic effects in some insects. Here we test the hypothesis that a bark extract of Cinnamosma fragrans (CINEX) and its major drimane sesquiterpenes are insecticidal, antifeedant, and repellent to Aedes aegypti, the principal mosquito vector of chikungunya, dengue, yellow fever, and Zika viruses. We demonstrate that CINEX is 1) toxic to larval and adult female mosquitoes, and 2) antifeedant and repellent to adult female mosquitoes. Moreover, we show that cinnamodial (CDIAL), a sesquiterpene dialdehyde isolated from CINEX, duplicates these bioactivities and exhibits similar toxic potency against pyrethroid-susceptible and -resistant strains of Ae. aegypti. Importantly, we show that CDIAL is an agonist of heterologously-expressed mosquito Transient Receptor Potential A1 (TRPA1) channels, and the antifeedant activity of CDIAL is dampened in a TRPA1-deficient strain of Ae. aegypti (TRPA1-/-). Intriguingly, TRPA1-/- mosquitoes do not exhibit toxic resistance to CDIAL. The data indicate that modulation of TRPA1 is required for the sensory detection and avoidance of CDIAL by mosquitoes, but not for inducing the molecule's toxicity. Our study suggests that CDIAL may serve as a novel chemical platform for the development of natural product-based insecticides and repellents for controlling mosquito vectors.

EPA Registers the Wolbachia ZAP Strain in Live Male Asian Tiger Mosquitoes

EPA Pesticide Factsheets

EPA registered a new mosquito biopesticide – ZAP Males® - that can reduce local populations of the type of mosquito (Aedes albopictus, or Asian Tiger Mosquitoes) that can spread numerous diseases of significant human health concern, including the Zika viru

Field evaluation of four widely used mosquito traps in Central Europe

PubMed Central

2014-01-01

Background To monitor adult mosquitoes several trapping devices are available. These are differently constructed and use various mechanisms for mosquito attraction, thus resulting in different trapping sensitivities and efficacies for the various species. Mosquito monitoring and surveillance programs in Europe use various types of mosquito traps, but only a few comparisons have been conducted so far. This study compared the performance of four commercial trapping devices, which are commonly used in Europe. Methods Four different traps, Biogents Sentinel trap (BG trap), Heavy Duty Encephalitis Vector Survey trap (EVS trap), Centres for Disease Control miniature light trap (CDC trap) and Mosquito Magnet Patriot Mosquito trap (MM trap) were compared in a 4 × 4 latin square study. In the years 2012 and 2013, more than seventy 24-hour trap comparisons were conducted at ten different locations in northern and southern Germany, representing urban, forest and floodplain biotopes. Results Per 24-hour trapping period, the BG trap caught the widest range of mosquito species, the highest number of individuals of the genus Culex as well as the highest number of individuals of the species Ochlerotatus cantans, Aedes cinereus/geminus, Oc. communis and Culex pipiens/torrentium. The CDC trap revealed best performance for Aedes vexans, whereas the MM trap was most efficient for mosquitoes of the genus Anopheles and the species Oc. geniculatus. The EVS trap did not catch more individuals of any genus or species compared to the other three trapping devices. The BG trap caught the highest number of individuals per trapping period in urban environments as well as in wet forest, while the CDC trap caught the highest number of individuals in the floodplain biotopes. Additionally, the BG trap was most efficient for the number of mosquito species in urban locations. Conclusion The BG trap showed a significantly better or similar performance compared to the CDC, EVS or MM trap with

Genetic divergence between populations of feral and domestic forms of a mosquito disease vector assessed by transcriptomics

PubMed Central

2015-01-01

Culex pipiens, an invasive mosquito and vector of West Nile virus in the US, has two morphologically indistinguishable forms that differ dramatically in behavior and physiology. Cx. pipiens form pipiens is primarily a bird-feeding temperate mosquito, while the sub-tropical Cx. pipiens form molestus thrives in sewers and feeds on mammals. Because the feral form can diapause during the cold winters but the domestic form cannot, the two Cx. pipiens forms are allopatric in northern Europe and, although viable, hybrids are rare. Cx. pipiens form molestus has spread across all inhabited continents and hybrids of the two forms are common in the US. Here we elucidate the genes and gene families with the greatest divergence rates between these phenotypically diverged mosquito populations, and discuss them in light of their potential biological and ecological effects. After generating and assembling novel transcriptome data for each population, we performed pairwise tests for nonsynonymous divergence (Ka) of homologous coding sequences and examined gene ontology terms that were statistically over-represented in those sequences with the greatest divergence rates. We identified genes involved in digestion (serine endopeptidases), innate immunity (fibrinogens and α-macroglobulins), hemostasis (D7 salivary proteins), olfaction (odorant binding proteins) and chitin binding (peritrophic matrix proteins). By examining molecular divergence between closely related yet phenotypically divergent forms of the same species, our results provide insights into the identity of rapidly-evolving genes between incipient species. Additionally, we found that families of signal transducers, ATP synthases and transcription regulators remained identical at the amino acid level, thus constituting conserved components of the Cx. pipiens proteome. We provide a reference with which to gauge the divergence reported in this analysis by performing a comparison of transcriptome sequences from conspecific

Fauna, Ecological Characteristics, and Checklist of the Mosquitoes in Mazandaran Province, Northern Iran.

PubMed

Nikookar, Seyed Hassan; Fazeli-Dinan, Mahmoud; Azari-Hamidian, Shahyad; Nasab, Seyed Nouraddin Mousavi; Aarabi, Mohsen; Ziapour, Seyyed Payman; Enayati, Ahmadali; Hemingway, Janet

2018-05-04

Mosquitoes are important vectors of human and animal diseases. This study updates current knowledge on fauna, dominance, and distribution of mosquitoes in Mazandaran Province, Northern Iran, to inform disease control effort. Larval collections, using standard dippers or droppers, and adult collections, using total catches, shelter pits, CDC light traps, and human landing catches, were performed monthly in 30 villages across 16 counties, from May to December 2014. Ovitraps, baited with hay infusion as oviposition attractants or stimulants for Aedes (Stegomyia) mosquitoes, were installed in each village and inspected weekly for eggs. Lactophenol and Berlese media were used for preserving and mounting specimens. Overall, 36,024 mosquito specimens (19,840 larvae and 16,184 adults) belonging to 4 genera and 20 species were morphologically identified. The dominance and distribution indices showed that Culex pipiens s.s. was the eudominant species with a constant distribution of larvae (D = 69.07%, C = 100%) and adults (D = 31.86%, C = 100%), followed by Cx tritaeniorhynchus (D = 38.14%, C = 100%) and Anopheles maculipennis s.l. (D = 11.05%, C = 100%) as adults. Aedes vexans was the dominant (7.85%) species, but it had a sporadic (20%) distribution. Culex torrentium and Culiseta morsitans were added as the new species to the checklist of mosquitoes in Mazandaran Province. Due to the potential role, Cx. pipiens s.s. as a vector of various pathogens, further ecological studies are recommended.

Insecticide resistance in Culex quinquefasciatus mosquitoes after the introduction of insecticide-treated bed nets in Macha, Zambia

PubMed Central

Norris, Douglas E.

2014-01-01

Culex quinquefasciatus , an arboviral and filarial vector, is present in high numbers throughout sub-Saharan Africa, and insecticide-resistant populations have been reported worldwide. In order to determine the insecticide resistance status of Cx. quinquefasciatus in Macha, Zambia, adult mosquitoes reared from eggs collected from oviposition traps were tested by bioassay. High levels of resistance to DDT, pyrethroids, malathion, and deltamethrin-treated net material were detected, and molecular assays revealed that the knockdown resistance (kdr) allele was frequent in the Cx. quinquefasciatus population, with 7.0% homozygous for the kdr L1014 allele and 38.5% heterozygous (0.263 kdr frequency). The kdr frequency was significantly higher in mosquitoes that had successfully fed on human hosts, and screening archived specimens revealed that kdr was present at lower frequency prior to the introduction of ITNs, indicating that ITNs might be a selective force in this population. Additionally, metabolic detoxification enzyme activity assays showed upregulated glutathione S-transferases, α-esterases, and β-esterases. Continued monitoring and assessment of the Cx. quinquefasciatus population is necessary to determine levels of resistance. PMID:22129413

Genetic diversity and population genetics of mosquitoes (Diptera: Culicidae: Culex spp.) from the Sonoran Desert of North America.

PubMed

Pfeiler, Edward; Flores-López, Carlos A; Mada-Vélez, Jesús Gerardo; Escalante-Verdugo, Juan; Markow, Therese A

2013-01-01

The population genetics and phylogenetic relationships of Culex mosquitoes inhabiting the Sonoran Desert region of North America were studied using mitochondrial DNA and microsatellite molecular markers. Phylogenetic analyses of mitochondrial cytochrome c oxidase subunit I (COI) from mosquitoes collected over a wide geographic area, including the Baja California peninsula, and mainland localities in southern Arizona, USA and Sonora, Mexico, showed several well-supported partitions corresponding to Cx. quinquefasciatus, Cx. tarsalis, and two unidentified species, Culex sp. 1 and sp. 2. Culex quinquefasciatus was found at all localities and was the most abundant species collected. Culex tarsalis was collected only at Tucson, Arizona and Guaymas, Sonora. The two unidentified species of Culex were most abundant at Navojoa in southern Sonora. Haplotype and nucleotide diversities in the COI gene segment were substantially lower in Cx. quinquefasciatus compared with the other three species. Analysis of molecular variance revealed little structure among seven populations of Cx. quinquefasciatus, whereas significant structure was found between the two populations of Cx. tarsalis. Evidence for an historical population expansion beginning in the Pleistocene was found for Cx. tarsalis. Possible explanations for the large differences in genetic diversity between Cx. quinquefasciatus and the other species of Culex are presented.

Genetic Diversity and Population Genetics of Mosquitoes (Diptera: Culicidae: Culex spp.) from the Sonoran Desert of North America

PubMed Central

Pfeiler, Edward; Flores-López, Carlos A.; Mada-Vélez, Jesús Gerardo; Escalante-Verdugo, Juan; Markow, Therese A.

2013-01-01

The population genetics and phylogenetic relationships of Culex mosquitoes inhabiting the Sonoran Desert region of North America were studied using mitochondrial DNA and microsatellite molecular markers. Phylogenetic analyses of mitochondrial cytochrome c oxidase subunit I (COI) from mosquitoes collected over a wide geographic area, including the Baja California peninsula, and mainland localities in southern Arizona, USA and Sonora, Mexico, showed several well-supported partitions corresponding to Cx. quinquefasciatus, Cx. tarsalis, and two unidentified species, Culex sp. 1 and sp. 2. Culex quinquefasciatus was found at all localities and was the most abundant species collected. Culex tarsalis was collected only at Tucson, Arizona and Guaymas, Sonora. The two unidentified species of Culex were most abundant at Navojoa in southern Sonora. Haplotype and nucleotide diversities in the COI gene segment were substantially lower in Cx. quinquefasciatus compared with the other three species. Analysis of molecular variance revealed little structure among seven populations of Cx. quinquefasciatus, whereas significant structure was found between the two populations of Cx. tarsalis. Evidence for an historical population expansion beginning in the Pleistocene was found for Cx. tarsalis. Possible explanations for the large differences in genetic diversity between Cx. quinquefasciatus and the other species of Culex are presented. PMID:24302868

MosquitoNet: investigating the use of UAV and artificial neural networks for integrated mosquito management

NASA Astrophysics Data System (ADS)

Case, E.; Ren, Y.; Shragai, T.; Erickson, D.

2017-12-01

Integrated mosquito control is expensive and resource intensive, and changing climatic factors are predicted to expand the habitable range of disease-carrying mosquitoes into new regions in the United States. Of particular concern in the northeastern United States are aedes albopictus, an aggressive, invasive species of mosquito that can transmit both native and exotic disease. Ae. albopictus prefer to live near human populations and breed in artificial containers with as little as two millimeters of standing water, exponentially increasing the difficulty of source control in suburban and urban areas. However, low-cost unmanned aerial vehicles (UAVs) can be used to photograph large regions at centimeter-resolution, and can image containers of interest in suburban neighborhoods. While proofs-of-concepts have been shown using UAVs to identify naturally occurring bodies of water, they have not been used to identify mosquito habitat in more populated areas. One of the primary challenges is that post-processing high-resolution aerial imagery is still time intensive, often labelled by hand or with programs built for satellite imagery. Artificial neural networks have been highly successful at image recognition tasks; in the past five years, convolutional neural networks (CNN) have surpassed or aided trained humans in identification of skin cancer, agricultural crops, and poverty levels from satellite imagery. MosquitoNet, a dual classifier built from the Single Shot Multibox Detector and VGG16 architectures, was trained on UAV­­­­­ aerial imagery taken during a larval study in Westchester County in southern New York State in July and August 2017. MosquitoNet was designed to assess the habitat risk of suburban properties by automating the identification and counting of containers like tires, toys, garbage bins, flower pots, etc. The SSD-based architecture marked small containers and other habitat indicators while the VGG16-based architecture classified the type of

Disrupting Mosquito Reproduction and Parasite Development for Malaria Control

PubMed Central

Gabrieli, Paolo; Buckee, Caroline O.; Catteruccia, Flaminia

2016-01-01

The control of mosquito populations with insecticide treated bed nets and indoor residual sprays remains the cornerstone of malaria reduction and elimination programs. In light of widespread insecticide resistance in mosquitoes, however, alternative strategies for reducing transmission by the mosquito vector are urgently needed, including the identification of safe compounds that affect vectorial capacity via mechanisms that differ from fast-acting insecticides. Here, we show that compounds targeting steroid hormone signaling disrupt multiple biological processes that are key to the ability of mosquitoes to transmit malaria. When an agonist of the steroid hormone 20-hydroxyecdysone (20E) is applied to Anopheles gambiae females, which are the dominant malaria mosquito vector in Sub Saharan Africa, it substantially shortens lifespan, prevents insemination and egg production, and significantly blocks Plasmodium falciparum development, three components that are crucial to malaria transmission. Modeling the impact of these effects on Anopheles population dynamics and Plasmodium transmission predicts that disrupting steroid hormone signaling using 20E agonists would affect malaria transmission to a similar extent as insecticides. Manipulating 20E pathways therefore provides a powerful new approach to tackle malaria transmission by the mosquito vector, particularly in areas affected by the spread of insecticide resistance. PMID:27977810

Mosquito-Disseminated Insecticide for Citywide Vector Control and Its Potential to Block Arbovirus Epidemics: Entomological Observations and Modeling Results from Amazonian Brazil

PubMed Central

Abad-Franch, Fernando; Luz, Sérgio L. B.

2017-01-01

Background Mosquito-borne viruses threaten public health worldwide. When the ratio of competent vectors to susceptible humans is low enough, the virus’s basic reproductive number (R0) falls below 1.0 (each case generating, on average, <1.0 additional case) and the infection fades out from the population. Conventional mosquito control tactics, however, seldom yield R0 < 1.0. A promising alternative uses mosquitoes to disseminate a potent growth-regulator larvicide, pyriproxyfen (PPF), to aquatic larval habitats; this kills most mosquito juveniles and substantially reduces adult mosquito emergence. We tested mosquito-disseminated PPF in Manacapuru, a 60,000-inhabitant city (~650 ha) in Amazonian Brazil. Methods and Findings We sampled juvenile mosquitoes monthly in 100 dwellings over four periods in February 2014–January 2016: 12 baseline months, 5 mo of citywide PPF dissemination, 3 mo of focal PPF dissemination around Aedes-infested dwellings, and 3 mo after dissemination ended. We caught 19,434 juvenile mosquitoes (66% Aedes albopictus, 28% Ae. aegypti) in 8,271 trap-months. Using generalized linear mixed models, we estimated intervention effects on juvenile catch and adult emergence while adjusting for dwelling-level clustering, unequal sampling effort, and weather-related confounders. Following PPF dissemination, Aedes juvenile catch decreased by 79%–92% and juvenile mortality increased from 2%–7% to 80%–90%. Mean adult Aedes emergence fell from 1,077 per month (range 653–1,635) at baseline to 50.4 per month during PPF dissemination (range 2–117). Female Aedes emergence dropped by 96%–98%, such that the number of females emerging per person decreased to 0.06 females per person-month (range 0.002–0.129). Deterministic models predict, under plausible biological-epidemiological scenarios, that the R0 of typical Aedes-borne viruses would fall from 3–45 at baseline to 0.004–0.06 during PPF dissemination. The main limitations of our study were

Distribution of mosquitoes and mosquito-borne arboviruses in Yunnan Province near the China-Myanmar-Laos border.

PubMed

Wang, Jinglin; Zhang, Hailin; Sun, Xiaohong; Fu, Shihong; Wang, Huanqin; Feng, Yun; Wang, Huanyu; Tang, Qing; Liang, Guo-Dong

2011-05-01

Economic development and increased tourism in the southern region of Yunnan Province in China, adjacent to several countries in Southeast Asia, has increased the likelihood of import and export of vectors and vector-borne diseases. We report the results of surveillance of mosquitoes and mosquito-borne arboviruses along the border of China-Myanmar-Laos in 2005 and 2006, and information associating several arboviruses with infections and possibly disease in local human populations. Seventeen mosquito species representing four genera were obtained, and 14 strains of mosquito-borne viruses representing six viruses in five genera were isolated from Culex tritaeniorhynchus. In addition, IgM against Japanese encephalitis virus, Sindbis virus, Yunnan orbivirus and novel Banna virus was detected in acute-phase serum samples obtained from hospitalized patients with fever and encephalitis near the areas where the viruses were isolated. This investigation suggests that Japanese encephalitis virus, Sindbis virus, and lesser-known arboviruses circulate and may be infecting humans in the China-Myanmar-Laos border region.

Antibiotic Utilization and the Role of Suspected and Diagnosed Mosquito-borne Illness Among Adults and Children With Acute Febrile Illness in Pune, India.

PubMed

Robinson, Matthew L; Kadam, Dileep; Kagal, Anju; Khadse, Sandhya; Kinikar, Aarti; Valvi, Chhaya; Basavaraj, Anita; Bharadwaj, Renu; Marbaniang, Ivan; Kanade, Savita; Raichur, Priyanka; Sachs, Jonathan; Klein, Eili; Cosgrove, Sara; Gupta, Amita; Mave, Vidya

2018-05-02

Antibiotic resistance mechanisms originating in low- and middle- income countries are among the most common worldwide. Reducing unnecessary antibiotic use in India, the world's largest antibiotic consumer, is crucial to control antimicrobial resistance globally. Limited data describing factors influencing Indian clinicians to start or stop antibiotics are available. Febrile adults and children admitted to a public tertiary care hospital in Pune, India, were enrolled. Antibiotic usage and clinical history were recorded. Immunoassays for mosquito-borne disease and bacterial cultures were performed by protocol and clinician-directed testing. Clinical factors were assessed for association with empiric antibiotic initiation and discontinuation by day 5 using multivariable logistic regression and propensity score-matched Cox proportional hazard models. Among 1486 participants, 683 (82%) adults and 614 (94%) children received empiric antibiotics. Participants suspected of having mosquito-borne disease were less likely to receive empiric antibiotics (adjusted odds ratio [AOR], 0.5; 95% confidence interval [CI], .4-.8). Empiric antibiotics were discontinued in 450 (35%) participants by day 5. Dengue or malaria testing performed before day 4 was positive in 162 (12%) participants, and was associated with antibiotic discontinuation (AOR, 1.7; 95% CI, 1.2-2.4). In a propensity score-matched model accounting for admission suspicion of mosquito-borne disease, positive dengue or malaria tests increased hazard of antibiotic discontinuation (hazard ratio, 1.6; 95% CI, 1.2-2.0). Most patients with acute febrile illness in an Indian public hospital setting receive empiric antibiotics. Mosquito-borne disease identification is associated with reduced empiric antibiotic use and faster antibiotic discontinuation.

French invasive Asian tiger mosquito populations harbor reduced bacterial microbiota and genetic diversity compared to Vietnamese autochthonous relatives

PubMed Central

Minard, G.; Tran, F. H.; Van, Van Tran; Goubert, C.; Bellet, C.; Lambert, G.; Kim, Khanh Ly Huynh; Thuy, Trang Huynh Thi; Mavingui, P.; Valiente Moro, C.

2015-01-01

The Asian tiger mosquito Aedes albopictus is one of the most significant pathogen vectors of the twenty-first century. Originating from Asia, it has invaded a wide range of eco-climatic regions worldwide. The insect-associated microbiota is now recognized to play a significant role in host biology. While genetic diversity bottlenecks are known to result from biological invasions, the resulting shifts in host-associated microbiota diversity has not been thoroughly investigated. To address this subject, we compared four autochthonous Ae. albopictus populations in Vietnam, the native area of Ae. albopictus, and three populations recently introduced to Metropolitan France, with the aim of documenting whether these populations display differences in host genotype and bacterial microbiota. Population-level genetic diversity (microsatellite markers and COI haplotype) and bacterial diversity (16S rDNA metabarcoding) were compared between field-caught mosquitoes. Bacterial microbiota from the whole insect bodies were largely dominated by Wolbachia pipientis. Targeted analysis of the gut microbiota revealed a greater bacterial diversity in which a fraction was common between French and Vietnamese populations. The genus Dysgonomonas was the most prevalent and abundant across all studied populations. Overall genetic diversities of both hosts and bacterial microbiota were significantly reduced in recently established populations of France compared to the autochthonous populations of Vietnam. These results open up many important avenues of investigation in order to link the process of geographical invasion to shifts in commensal and symbiotic microbiome communities, as such shifts may have dramatic impacts on the biology and/or vector competence of invading hematophagous insects. PMID:26441903

The first detected airline introductions of yellow fever mosquitoes (Aedes aegypti) to Europe, at Schiphol International airport, the Netherlands.

PubMed

Ibañez-Justicia, A; Gloria-Soria, A; den Hartog, W; Dik, M; Jacobs, F; Stroo, A

2017-12-08

Air-borne introduction of exotic mosquitoes to Schiphol airport in the Netherlands has been considered plausible based upon findings of mosquitoes in aircraft cabins during 2008, 2010 and 2011. Beginning in 2013, surveillance efforts at Schiphol had focused on promptly detecting accidental introductions at the airport facilities in order to quickly react and avoid temporary proliferation or establishment of mosquito populations, identify the origin of the introductions, and avoid potential transmission of vector-borne diseases. BG-Mosquitaire mosquito traps were set at the most likely locations for arrival of the invasive Aedes mosquitoes as part of the mosquito monitoring program at Schiphol airport. Samples were collected bi-weekly. Upon detection of exotic specimens, information about the origin of the flights arriving to the particular location at the airport where specimens were captured was requested from airport authorities. The GIS tool Intersect was then used to identify airports of origin common to positive trapping locations during the specific trapping period. Captured Aedes aegypti mosquitoes were subsequently genotyped at 12 highly polymorphic microsatellite markers and compared to a reference database of 79 populations around the world to further narrow down their location of origin. In 2016, six adult yellow fever mosquitoes were captured indoors and outdoors at the airport of Schiphol in the Netherlands confirming, for the first time, air-borne transport of this mosquito vector species into Europe. Mosquitoes were captured during three time periods: June, September and October. Containers carried by aircrafts are considered the most likely pathway for this introduction. GIS analysis and genetic assignment tests on these mosquitoes point to North America or the Middle East as possible origins, but the small sample size prevents us from reliably identifying the geographic origin of this introduction. The arrival of Ae. aegypti mosquitoes to Schiphol

RNA-Seq Comparison of Larval and Adult Malpighian Tubules of the Yellow Fever Mosquito Aedes aegypti Reveals Life Stage-Specific Changes in Renal Function.

PubMed

Li, Yiyi; Piermarini, Peter M; Esquivel, Carlos J; Drumm, Hannah E; Schilkey, Faye D; Hansen, Immo A

2017-01-01

Introduction: The life history of Aedes aegypti presents diverse challenges to its diuretic system. During the larval and pupal life stages mosquitoes are aquatic. With the emergence of the adult they become terrestrial. This shifts the organism within minutes from an aquatic environment to a terrestrial environment where dehydration has to be avoided. In addition, female mosquitoes take large blood meals, which present an entirely new set of challenges to salt and water homeostasis. Methods: To determine differences in gene expression associated with these different life stages, we performed an RNA-seq analysis of the main diuretic tissue in A. aegypti , the Malpighian tubules. We compared transcript abundance in 4th instar larvae to that of adult females and analyzed the data with a focus on transcripts that encode proteins potentially involved in diuresis, like water and solute channels as well as ion transporters. We compared our results against the model of potassium- and sodium chloride excretion in the Malpighian tubules proposed by Hine et al. (2014), which involves at least eight ion transporters and a proton-pump. Results: We found 3,421 of a total number of 17,478 (19.6%) unique transcripts with a P < 0.05 and at least a 2.5 fold change in expression levels between the two groups. We identified two novel transporter genes that are highly expressed in the adult Malpighian tubules, which have not previously been part of the transport model in this species and may play important roles in diuresis. We also identified candidates for hypothesized sodium and chloride channels. Detoxification genes were generally higher expressed in larvae. Significance: This study represents the first comparison of Malpighian tubule transcriptomes between larval and adult A. aegypti mosquitoes, highlighting key differences in their renal systems that arise as they transform from an aquatic filter-feeding larval stage to a terrestrial, blood-feeding adult stage.

A geospatial study of the potential of two exotic species of mosquitoes to impact the epidemiology of West Nile virus in Maryland.

PubMed

Kutz, Frederick W; Wade, Timothy G; Pagac, Benedict B

2003-09-01

We used geospatial techniques to study the potential impact of 2 exotic mosquitoes, Aedes albopictus and Ochlerotatus japonicus japonicus, on the epidemiology of West Nile virus in Maryland. These 2 species have established populations in Maryland over the past 15 years. Larvae of both mosquito species are found in natural and artificial water-holding cavities and containers, particularly water in tires. Therefore, we used locations of licensed tire dealers and of tire dumps scheduled for clean up as an index for potential sources of mosquito vectors. This index was expected to underestimate the actual population of source habitats. West Nile virus activity in Maryland during 1999, 2000, and 2001 was indicated by the presence of dead, infected birds, particularly American crows and other corvids; infected pools of mosquitoes; and human and horse infections. Adult females of both mosquito species are aggressive, opportunistic feeders that have been observed to take blood meals from avian and mammalian hosts. Susceptible vertebrate hosts, particularly birds, are ubiquitously distributed throughout the developed areas of the state. This analysis demonstrated a spatial convergence of the virus, the exotic mosquito vectors, and susceptible hosts. This conjunction indicated that these 2 mosquito species have a high potential to serve as bridge vectors and thus, impact the epidemiology of West Nile virus under favorable environmental and climatic conditions. Positive mosquito pools were collected from only the Baltimore-Washington metropolitan corridor, suggesting a newly created enzootic focus for this virus. Land-cover analysis of the sites where virus activity had been detected showed predominantly developed land uses. Analyses of the environmental justice aspects (social, economic, and housing characteristics) of block groups with human West Nile fever cases or with positive mosquito pools were equivocal. Human cases seemed to occur in developed block groups with

Effect of ebastine on mosquito bites.

PubMed

Reunala, T; Brummer-Korvenkontio, H; Petman, L; Palosuo, T; Sarna, S

1997-07-01

Mosquito bites usually cause wealing and delayed bite papules. Cetirizine decreases wealing, bite papules and pruritus but the effect of other antihistamines on mosquito bites is unknown. We studied the effect of ebastine in 30 mosquito bite-sensitive adult subjects. Ebastine 10 mg or 20 mg and placebo were given for 4 days in a cross-over fashion. Aedes aegypti bites were given on forearms. The size of the bite lesions and pruritus (visual analogue score) were measured at 15 min, 2, 6, and 24 h after the bites. Twenty-five subjects were evaluable in the study. At 15 min ebastine decreased significantly the size of the bite lesion (p = 0.0017) and pruritus (p<0.0001). The effects of 10 mg and 20 mg of ebastine were similar. No significant effect was found at 2, 6 or 24 h, but when the measurements at all four time points were compiled the size of the bite lesion and pruritus score decreased significantly. Sedation occurred during ebastine treatment in 6 (21%) and during placebo treatment in 2 (7%) subjects. The present results show that prophylactically given ebastine is effective against immediate mosquito bite symptoms.

Japanese encephalitis on Saipan: a survey of suspected mosquito vectors.

PubMed

Mitchell, C J; Savage, H M; Smith, G C; Flood, S P; Castro, L T; Roppul, M

1993-04-01

An outbreak of Japanese encephalitis (JE) occurred on Saipan, Commonwealth of Northern Mariana Islands, in October 1990. Adult and larval mosquitoes were collected during September-October 1991 to retrospectively determine the probable mosquito vector(s). Virus was not isolated from 119 mosquito pools composed of 7,250 adult specimens as follows: Aedes vexans nocturnis (14%), Culex tritaeniorhynchus (39%), Cx. sitiens group (11%), Culex (Culex) species (35%), and < 1% each of Ae. albopictus, Ae. oakleyi, Aedes saipanensis, Cx. annulirostris marianae, and Cx. fuscanus. Three additional species were collected only as larvae: Anopheles indefinitus, Ae. neopandani, and Cx. quinquefasciatus. Among the vectors of JE incriminated in other areas, Cx. tritaeniorhynchus was the predominant species in our collections and the principal species feeding on swine. This is the first published record of the occurrence of this species on Saipan. Culex tritaeniorhynchus is abundant and widely distributed on the southern half of Saipan where human JE cases occurred in 1990, and where swine seroconversions were detected. Although the identity of the mosquito vector(s) responsible for the 1990 outbreak cannot be established with certainty, our results suggest that Cx. tritaeniorhychus was probably involved.

Modeled response of the West Nile virus vector Culex quinquefasciatus to changing climate using the dynamic mosquito simulation model

NASA Astrophysics Data System (ADS)

Morin, Cory W.; Comrie, Andrew C.

2010-09-01

Climate can strongly influence the population dynamics of disease vectors and is consequently a key component of disease ecology. Future climate change and variability may alter the location and seasonality of many disease vectors, possibly increasing the risk of disease transmission to humans. The mosquito species Culex quinquefasciatus is a concern across the southern United States because of its role as a West Nile virus vector and its affinity for urban environments. Using established relationships between atmospheric variables (temperature and precipitation) and mosquito development, we have created the Dynamic Mosquito Simulation Model (DyMSiM) to simulate Cx. quinquefasciatus population dynamics. The model is driven with climate data and validated against mosquito count data from Pasco County, Florida and Coachella Valley, California. Using 1-week and 2-week filters, mosquito trap data are reproduced well by the model ( P < 0.0001). Dry environments in southern California produce different mosquito population trends than moist locations in Florida. Florida and California mosquito populations are generally temperature-limited in winter. In California, locations are water-limited through much of the year. Using future climate projection data generated by the National Center for Atmospheric Research CCSM3 general circulation model, we applied temperature and precipitation offsets to the climate data at each location to evaluate mosquito population sensitivity to possible future climate conditions. We found that temperature and precipitation shifts act interdependently to cause remarkable changes in modeled mosquito population dynamics. Impacts include a summer population decline from drying in California due to loss of immature mosquito habitats, and in Florida a decrease in late-season mosquito populations due to drier late summer conditions.

“Looking over the Backyard Fence”: Householders and Mosquito Control

PubMed Central

Mainali, Samir; Lamichhane, Ram Sharan; Clark, Kim; Beatty, Shelley; Fatouros, Maria; Neville, Peter; Oosthuizen, Jacques

2017-01-01

(1) Background: Vector-borne diseases are a significant public health problem in Western Australia. Mosquitoes are responsible for the transmission of a number of pathogens and may pose a serious nuisance problem. Prevention efforts in the State are multi-faceted and include physical, chemical, and cultural control methods for restricting mosquito breeding. This is less complex where breeding areas are located within public open spaces. In Australia’s developed urban areas, breeding sites are, however, frequently located within private residential landholdings, where the scope of public health officials to act is constrained by law and practicality. Consequently, mosquito prevention in these locations is predominantly the responsibility of the residents. This research addressed a gap, both in understanding the degree to which “backyard” mosquito breeding has the potential to contribute to local mosquito problems, and in assessing what residents “think and do” about mosquito control within their home environment. (2) Methods: The study was conducted in the Town of Bassendean, a metropolitan Local Government Area of Perth, Western Australia, in close proximity to two natural, productive mosquito breeding sites, namely Ashfield Flats and Bindaring Park. A total of 150 householders were randomly surveyed during the summer of 2015–2016, to gauge residents’ knowledge, attitudes, and practices (KAP (knowledge, attitudes, and practices) Survey) in regards to mosquitoes, their breeding and ecology, and avoidance or minimization strategies. The survey comprised nine questions covering residents’ knowledge (3 questions), attitudes (3 questions), and practices (3 questions), as well as additional questions regarding the basic demographics of the resident. Larvae were collected from backyard containers and reared to adults for species identification. A series of Encephalitis Vector Surveillance carbon dioxide (EVS CO2) traps were also deployed, to assess adult

Early warning of West Nile virus mosquito vector: climate and land use models successfully explain phenology and abundance of Culex pipiens mosquitoes in north-western Italy.

PubMed

Rosà, Roberto; Marini, Giovanni; Bolzoni, Luca; Neteler, Markus; Metz, Markus; Delucchi, Luca; Chadwick, Elizabeth A; Balbo, Luca; Mosca, Andrea; Giacobini, Mario; Bertolotti, Luigi; Rizzoli, Annapaola

2014-06-12

West Nile Virus (WNV) is an emerging global health threat. Transmission risk is strongly related to the abundance of mosquito vectors, typically Culex pipiens in Europe. Early-warning predictors of mosquito population dynamics would therefore help guide entomological surveillance and thereby facilitate early warnings of transmission risk. We analysed an 11-year time series (2001 to 2011) of Cx. pipiens mosquito captures from the Piedmont region of north-western Italy to determine the principal drivers of mosquito population dynamics. Linear mixed models were implemented to examine the relationship between Cx. pipiens population dynamics and environmental predictors including temperature, precipitation, Normalized Difference Water Index (NDWI) and the proximity of mosquito traps to urban areas and rice fields. Warm temperatures early in the year were associated with an earlier start to the mosquito season and increased season length, and later in the year, with decreased abundance. Early precipitation delayed the start and shortened the length of the mosquito season, but increased total abundance. Conversely, precipitation later in the year was associated with a longer season. Finally, higher NDWI early in the year was associated with an earlier start to the season and increased season length, but was not associated with abundance. Proximity to rice fields predicted higher total abundance when included in some models, but was not a significant predictor of phenology. Proximity to urban areas was not a significant predictor in any of our models. Predicted variations in start of the season and season length ranged from one to three weeks, across the measured range of variables. Predicted mosquito abundance was highly variable, with numbers in excess of 1000 per trap per year when late season temperatures were low (average 21°C) to only 150 when late season temperatures were high (average 30°C). Climate data collected early in the year, in conjunction with local land

Pyrethroid resistance in Aedes aegypti and Aedes albopictus: Important mosquito vectors of human diseases.

PubMed

Smith, Letícia B; Kasai, Shinji; Scott, Jeffrey G

2016-10-01

Aedes aegypti and A. albopictus mosquitoes are vectors of important human disease viruses, including dengue, yellow fever, chikungunya and Zika. Pyrethroid insecticides are widely used to control adult Aedes mosquitoes, especially during disease outbreaks. Herein, we review the status of pyrethroid resistance in A. aegypti and A. albopictus, mechanisms of resistance, fitness costs associated with resistance alleles and provide suggestions for future research. The widespread use of pyrethroids has given rise to many populations with varying levels of resistance worldwide, albeit with substantial geographical variation. In adult A. aegypti and A. albopictus, resistance levels are generally lower in Asia, Africa and the USA, and higher in Latin America, although there are exceptions. Susceptible populations still exist in several areas of the world, particularly in Asia and South America. Resistance to pyrethroids in larvae is also geographically widespread. The two major mechanisms of pyrethroid resistance are increased detoxification due to P450-monooxygenases, and mutations in the voltage sensitive sodium channel (Vssc) gene. Several P450s have been putatively associated with insecticide resistance, but the specific P450s involved are not fully elucidated. Pyrethroid resistance can be due to single mutations or combinations of mutations in Vssc. The presence of multiple Vssc mutations can lead to extremely high levels of resistance. Suggestions for future research needs are presented. Copyright © 2016 Elsevier B.V. All rights reserved.

In a warmer Arctic, mosquitoes avoid increased mortality from predators by growing faster.

PubMed

Culler, Lauren E; Ayres, Matthew P; Virginia, Ross A

2015-09-22

Climate change is altering environmental temperature, a factor that influences ectothermic organisms by controlling rates of physiological processes. Demographic effects of warming, however, are determined by the expression of these physiological effects through predator-prey and other species interactions. Using field observations and controlled experiments, we measured how increasing temperatures in the Arctic affected development rates and mortality rates (from predation) of immature Arctic mosquitoes in western Greenland. We then developed and parametrized a demographic model to evaluate how temperature affects survival of mosquitoes from the immature to the adult stage. Our studies showed that warming increased development rate of immature mosquitoes (Q10 = 2.8) but also increased daily mortality from increased predation rates by a dytiscid beetle (Q10 = 1.2-1.5). Despite increased daily mortality, the model indicated that faster development and fewer days exposed to predators resulted in an increased probability of mosquito survival to the adult stage. Warming also advanced mosquito phenology, bringing mosquitoes into phenological synchrony with caribou. Increases in biting pests will have negative consequences for caribou and their role as a subsistence resource for local communities. Generalizable frameworks that account for multiple effects of temperature are needed to understand how climate change impacts coupled human-natural systems. © 2015 The Author(s).

Exotic mosquito threats require strategic surveillance and response planning.

PubMed

Webb, Cameron E; Doggett, Stephen L

2016-12-14

Mosquito-borne diseases caused by endemic pathogens such as Ross River, Barmah Forest and Murray Valley encephalitis viruses are an annual concern in New South Wales (NSW), Australia. More than a dozen mosquito species have been implicated in the transmission of these pathogens, with each mosquito occupying a specialised ecological niche that influences their habitat associations, host feeding preferences and the environmental drivers of their abundance. The NSW Arbovirus Surveillance and Mosquito Monitoring Program provides an early warning system for potential outbreaks of mosquito-borne disease by tracking annual activity of these mosquitoes and their associated pathogens. Although the program will effectively track changes in local mosquito populations that may increase with a changing climate, urbanisation and wetland rehabilitation, it will be less effective with current surveillance methodologies at detecting or monitoring changes in exotic mosquito threats, where different surveillance strategies need to be used. Exotic container-inhabiting mosquitoes such as Aedes aegypti and Ae. albopictus pose a threat to NSW because they are nuisance-biting pests and vectors of pathogens such as dengue, chikungunya and Zika viruses. International movement of humans and their belongings have spread these mosquitoes to many regions of the world. In recent years, these two mosquitoes have been detected by the Australian Government Department of Agriculture and Water Resources at local airports and seaports. To target the detection of these exotic mosquitoes, new trapping technologies and networks of surveillance locations are required. Additionally, incursions of these mosquitoes into urban areas of the state will require strategic responses to minimise substantial public health and economic burdens to local communities.

Community Ecology of Container Mosquitoes (Diptera: Culicidae) in Virginia Following Invasion by Aedes japonicus

PubMed Central

ARMISTEAD, JENNIFER S.; NISHIMURA, NAOYA; ARIAS, JORGE R.; LOUNIBOS, L. PHILIP

2012-01-01

The success of an invasive species in a new region depends on its interactions with ecologically similar resident species. Invasions by disease vector mosquitoes are important as they may have ecological and epidemiological consequences. Potential interactions of a recent invasive mosquito, Aedes japonicus Theobald, with resident species in Virginia were evaluated by sampling larvae from containers and trapping adults. Distinct species compositions were observed for artificial containers and rock pools, with Ae. albopictus most abundant in the former and Ae. japonicus in the latter. However, these two species were found to co-occur in 21.2% of containers sampled. Among the six mosquito species most common in containers from May through September, 2006, only interspecific associations of Ae.japonicus with Aedesalbopictus(Skuse) and Aedestriseriatus(Say) were significant, and both were negative. In addition to differences in habitat preference, mean crowding estimates suggest that interspecific repulsion may contribute to the significant negative associations observed between these species. High relative abundances of late instars and pupae of Ae. japonicus seem to provide this species with a mechanism of evading competition with Ae. albopictus, facilitating their coexistence in artificial containers. Although annual fluctuations were observed, trends in adult populations over a 6-yr period provide no evidence of declines. In summary, this survey of diverse container types and all life stages provided only limited evidence for competitive displacements or reductions of resident container species by Ae. japonicus, as observed elsewhere in its invasive range. PMID:23270159

Mosquitoes Associated with Ditch-Plugged and Control Tidal Salt Marshes on the Delmarva Peninsula

PubMed Central

Leisnham, Paul T.; Sandoval-Mohapatra, Sarah

2011-01-01

A study was conducted during the summer of 2009 (from July to September) to characterize mosquito communities among different habitats in five historically ditched tidal salt marshes and three adjacent wooded areas in the E.A. Vaughn Wetland Management Area on the Maryland Delmarva Peninsula, USA. Study marshes are characteristic of Atlantic coastal salt marshes that had undergone grid ditching from the 1930s to 1950s. In the autumn of 2008 (October and November) ditches were plugged near their outlets in two (‘experimental’) marshes with the aim to restore their natural tidal hydrology. The three other marshes were not plugged. Marshes were sampled from July to September in 2009 by using standard dip count method. A total of 2,457 mosquito larvae representing six species were collected on 15.4% (86/557) of all sample occasions and 399 adults representing four mosquito species were collected from landing counts. Aedes sollicitans, Anopheles bradleyi and Culex salinarius were the most common species collected in larval habitats, and Ae. sollicitans was the most common adult collected. Wooded habitats had more total mosquitoes, were also more frequently occupied by mosquitoes and had higher densities of mosquitoes than marsh habitats. Almost all larvae collected from marshes were from one experimental and one control site. The majority of larvae at the control site were Ae. sollicitans in marsh pannes while Cx. salinarius, An. bradleyi, Ae. cantator, and Ae. sollicitans were collected in high numbers from ditches at the experimental site. We found a difference in the proportion of marsh pannes occupied by Ae. sollicitans but not total mosquitoes sampled 4–5 days after spring tide events than on other occasions. Salinity measures of 42 larval habitats showed lower median salinity in mosquito-occupied habitats (11.5 ppt) than unoccupied habitats (20.1 ppt), and in habitats in wooded areas followed by ditches and pannes in marsh areas. The results of this study

Comparison of cetirizine, ebastine and loratadine in the treatment of immediate mosquito-bite allergy.

PubMed

Karppinen, A; Kautiainen, H; Petman, L; Burri, P; Reunala, T

2002-06-01

People frequently experience whealing and delayed papules from mosquito bites. Whealing is mediated by antisaliva immunoglobulin (Ig)E antibodies and histamine. Cetirizine, ebastine and loratadine have earlier shown effects on mosquito-bite reactions but no comparative studies exist. A double-blind, placebo-controlled, cross-over study was performed with cetirizine 10 mg, ebastine 10 mg and loratadine 10 mg in 29 mosquito-bite-sensitive adults exposed to Aedes aegypti mosquito-bites. The size of the bite lesion and the intensity of pruritus (visual analog scale) were measured at 15 min and 2, 6 and 24 h. Cetirizine and ebastine, but not loratadine, decreased significantly the size of whealing (P < 0.01) and accompanying pruritus (P < 0.001) compared to placebo. Cetirizine was most effective on pruritus but caused more often sedation than ebastine or loratadine. The delayed bite symptoms remained too faint for any statistical comparison. This comparative study in mosquito-bite-sensitive adults shows that cetirizine and ebastine decrease significantly whealing and accompanying pruritus, and that cetirizine seems to be the most effective against pruritus.

Establishment of a medium-scale mosquito facility: tests on mass production cages for Aedes albopictus (Diptera: Culicidae).

PubMed

Zhang, Dongjing; Li, Yongjun; Sun, Qiang; Zheng, Xiaoying; Gilles, Jeremie R L; Yamada, Hanano; Wu, Zhongdao; Xi, Zhiyong; Wu, Yu

2018-03-19

Mass egg production is an important component of Aedes albopictus mosquito control programs, such as the sterile insect technique and incompatible insect technique, which requires the releases of large number of sterile males. Developing standard operating procedures and optimized cages for adult maintenance of Ae. albopictus can improve the mass rearing efficiency. Three different sex ratios of females to males with a total number of 4,000 mosquitoes were tested by evaluating the insemination rate, egg production (total number of eggs per cage), female fecundity and egg hatch rate in small cage (30 × 30 × 30 cm). Blood meals with adenosine triphosphate (ATP, 0.05 g/ml), cage structures (Big cage A: 90 × 30 × 30 cm; Big cage B: 90 × 30 × 50 cm or 90 × 50 × 30 cm) and rearing densities (12,000, 16,000 and 20,000 mosquitoes, corresponding to 0.9 cm 2 /mosquito, 0.675 cm 2 /mosquito and 0.54 cm 2 /mosquito, respectively) were also tested and evaluated on the basis of egg production, female fecundity and egg hatch rate. An adult rearing unit holding 15 of Big cage A with optimal egg production was designed to produce 10 million eggs per rearing cycle in a 1.8 m 2 space. Female to male ratios at 3:1 in small cages resulted in higher egg production but did not affect insemination rate, female fecundity and egg hatch rate. A concentration of 0.05 g/ml of ATP added to blood meals improved the blood-feeding frequency and thus increased the overall egg production per cage. Cage structures affected the egg production per cage, but not egg hatch rate. A medium rearing density at 0.675 cm 2 /mosquito (16,000 mosquitoes) resulted in higher egg production compared to both low and high densities. An adult rearing unit for Ae. albopictus on the basis of Big cage A has been developed with the capacity of producing 10 million eggs within 15 days. Our results have indicated that the adult rearing methods and adult maintenance unit are recommended for Ae. albopictus mass

Wild Anopheles funestus mosquito genotypes are permissive for infection with the rodent malaria parasite, Plasmodium berghei.

PubMed

Xu, Jiannong; Hillyer, Julián F; Coulibaly, Boubacar; Sacko, Madjou; Dao, Adama; Niaré, Oumou; Riehle, Michelle M; Traoré, Sekou F; Vernick, Kenneth D

2013-01-01

Malaria parasites undergo complex developmental transitions within the mosquito vector. A commonly used laboratory model for studies of mosquito-malaria interaction is the rodent parasite, P. berghei. Anopheles funestus is a major malaria vector in sub-Saharan Africa but has received less attention than the sympatric species, Anopheles gambiae. The imminent completion of the A. funestus genome sequence will provide currently lacking molecular tools to describe malaria parasite interactions in this mosquito, but previous reports suggested that A. funestus is not permissive for P. berghei development. An A. funestus population was generated in the laboratory by capturing female wild mosquitoes in Mali, allowing them to oviposit, and rearing the eggs to adults. These F1 progeny of wild mosquitoes were allowed to feed on mice infected with a fluorescent P. berghei strain. Fluorescence microscopy was used to track parasite development inside the mosquito, salivary gland sporozoites were tested for infectivity to mice, and parasite development in A. funestus was compared to A. gambiae. P. berghei oocysts were detectable on A. funestus midguts by 7 days post-infection. By 18-20 days post-infection, sporozoites had invaded the median and distal lateral lobes of the salivary glands, and hemocoel sporozoites were observed in the hemolymph. Mosquitoes were capable of infecting mice via bite, demonstrating that A. funestus supports the complete life cycle of P. berghei. In a random sample of wild mosquito genotypes, A. funestus prevalence of infection and the characteristics of parasite development were similar to that observed in A. gambiae-P. berghei infections. The data presented in this study establish an experimental laboratory model for Plasmodium infection of A. funestus, an important vector of human malaria. Studying A. funestus-Plasmodium interactions is now feasible in a laboratory setting. This information lays the groundwork for exploitation of the awaited genome

Patterns of phenoloxidase activity in insecticide resistant and susceptible mosquitoes differ between laboratory-selected and wild-caught individuals.

PubMed

Cornet, Stéphane; Gandon, Sylvain; Rivero, Ana

2013-10-31

Insecticide resistance has the potential to alter vector immune competence and consequently affect the transmission of diseases. Using both laboratory isogenic strains and field-caught Culex pipiens mosquitoes, we investigated the effects of insecticide resistance on an important component of the mosquito immune system: the phenoloxidase (PO) activity. As infection risk varies dramatically with the age and sex of mosquitoes, allocation to PO immunity was quantified across different stages of the mosquito life cycle. Our results were consistent in showing that larvae have a higher PO activity than adults, females have a higher PO activity than males, and PO activity declines with adult age. We obtained, however, a marked discrepancy between laboratory and field-collected mosquitoes on the effect of insecticide resistance on PO activity. In the laboratory selected strains we found evidence of strong interactions between insecticide resistance and the age and sex of mosquitoes. In particular, 7 and 14 day old esterase-resistant adult females and acetylcholine-esterase resistant males had significantly higher PO activities than their susceptible counterparts. No such effects were, however, apparent in field-caught mosquitoes. Combined, the field and laboratory-based approaches employed in this study provide a powerful test of the effect of insecticide resistance on PO-mediated immunity. The use of laboratory-selected insecticide-resistant strains is still the most widely used method to investigate the pleiotropic effects of insecticide resistance. Our results suggest that the outcome of these laboratory-selected mosquitoes must be interpreted with caution and, whenever possible, compared with mosquitoes captured from the field.

Seasonal variation in wing size and shape between geographic populations of the malaria vector, Anopheles coluzzii in Burkina Faso (West Africa).

PubMed

Hidalgo, Kevin; Dujardin, Jean-Pierre; Mouline, Karine; Dabiré, Roch K; Renault, David; Simard, Frederic

2015-03-01

The mosquito, Anopheles coluzzii is a major vector of human malaria in Africa with widespread distribution throughout the continent. The species hence populates a wide range of environments in contrasted ecological settings often exposed to strong seasonal fluctuations. In the dry savannahs of West Africa, this mosquito population dynamics closely follows the pace of surface water availability: the species pullulates during the rainy season and is able to reproduce throughout the dry season in areas where permanent water bodies are available for breeding. The impact of such environmental fluctuation on mosquito development and the phenotypic quality of emerging adults has however not been addressed in details. Here, we examined and compared phenotypic changes in the duration of pre-imaginal development, body dry mass at emergence and wing size, shape and surface area in young adult females An. coluzzii originated from five distinct geographic locations when they are reared in two contrasting conditions mimicking those experienced by mosquitoes during the rainy season (RS) and at the onset of the dry season (ODS) in Burkina Faso (West Africa). Our results demonstrated strong phenotypic plasticity in all traits, with differences in the magnitude and direction of changes between RS and ODS depending upon the geographic origin, hence the genetic background of the mosquito populations. Highest heterogeneity within population was observed in Bama, where large irrigation schemes allow year-round mosquito breeding. Further studies are needed to explore the adaptive value of such phenotypic plasticity and its relevance for local adaptation in An. coluzzii. Copyright © 2015 Elsevier B.V. All rights reserved.

Insecticide resistance in Culex quinquefasciatus mosquitoes after the introduction of insecticide-treated bed nets in Macha, Zambia.

PubMed

Norris, Laura C; Norris, Douglas E

2011-12-01

Culex quinquefasciatus, an arboviral and filarial vector, is present in high numbers throughout sub-Saharan Africa, and insecticide-resistant populations have been reported worldwide. In order to determine the insecticide resistance status of Cx. quinquefasciatus in Macha, Zambia, adult mosquitoes reared from eggs collected from oviposition traps were tested by bioassay. High levels of resistance to DDT, pyrethroids, malathion, and deltamethrin-treated net material were detected, and molecular assays revealed that the knockdown resistance (kdr) allele was frequent in the Cx. quinquefasciatus population, with 7.0% homozygous for the kdr L1014 allele and 38.5% heterozygous (0.263 kdr frequency). The kdr frequency was significantly higher in mosquitoes that had successfully fed on human hosts, and screening archived specimens revealed that kdr was present at lower frequency prior to the introduction of ITNs, indicating that ITNs might be a selective force in this population. Additionally, metabolic detoxification enzyme activity assays showed upregulated glutathione S-transferases, α-esterases, and β-esterases. Continued monitoring and assessment of the Cx. quinquefasciatus population is necessary to determine levels of resistance. © 2011 The Society for Vector Ecology.

Using mobile phones as acoustic sensors for high-throughput mosquito surveillance.

PubMed

Mukundarajan, Haripriya; Hol, Felix Jan Hein; Castillo, Erica Araceli; Newby, Cooper; Prakash, Manu

2017-10-31

The direct monitoring of mosquito populations in field settings is a crucial input for shaping appropriate and timely control measures for mosquito-borne diseases. Here, we demonstrate that commercially available mobile phones are a powerful tool for acoustically mapping mosquito species distributions worldwide. We show that even low-cost mobile phones with very basic functionality are capable of sensitively acquiring acoustic data on species-specific mosquito wingbeat sounds, while simultaneously recording the time and location of the human-mosquito encounter. We survey a wide range of medically important mosquito species, to quantitatively demonstrate how acoustic recordings supported by spatio-temporal metadata enable rapid, non-invasive species identification. As proof-of-concept, we carry out field demonstrations where minimally-trained users map local mosquitoes using their personal phones. Thus, we establish a new paradigm for mosquito surveillance that takes advantage of the existing global mobile network infrastructure, to enable continuous and large-scale data acquisition in resource-constrained areas.

Using mobile phones as acoustic sensors for high-throughput mosquito surveillance

PubMed Central

Mukundarajan, Haripriya; Hol, Felix Jan Hein; Castillo, Erica Araceli; Newby, Cooper

2017-01-01

The direct monitoring of mosquito populations in field settings is a crucial input for shaping appropriate and timely control measures for mosquito-borne diseases. Here, we demonstrate that commercially available mobile phones are a powerful tool for acoustically mapping mosquito species distributions worldwide. We show that even low-cost mobile phones with very basic functionality are capable of sensitively acquiring acoustic data on species-specific mosquito wingbeat sounds, while simultaneously recording the time and location of the human-mosquito encounter. We survey a wide range of medically important mosquito species, to quantitatively demonstrate how acoustic recordings supported by spatio-temporal metadata enable rapid, non-invasive species identification. As proof-of-concept, we carry out field demonstrations where minimally-trained users map local mosquitoes using their personal phones. Thus, we establish a new paradigm for mosquito surveillance that takes advantage of the existing global mobile network infrastructure, to enable continuous and large-scale data acquisition in resource-constrained areas. PMID:29087296

Efficacy of Two Common Methods of Application of Residual Insecticide for Controlling the Asian Tiger Mosquito, Aedes albopictus (Skuse), in Urban Areas.

PubMed

Marini, Lorenzo; Baseggio, Alberto; Drago, Andrea; Martini, Simone; Manella, Paolo; Romi, Roberto; Mazzon, Luca

2015-01-01

After its first introduction in the 1980's the Asian tiger mosquito, Aedes albopictus (Skuse), has spread throughout Southern Europe. Ae. albopictus is considered an epidemiologically important vector for the transmission of many viral pathogens such as the yellow fever virus, dengue fever and Chikungunya fever, as well as several filarial nematodes such as Dirofilaria immitis or D. repens. It is therefore crucial to develop measures to reduce the risks of disease transmission by controlling the vector populations. The aim of the study was to compare the efficacy of two application techniques (mist vs. stretcher sprayer) and two insecticides (Etox based on the nonester pyrethroid Etofenprox vs. Microsin based on the pyrethroid type II Cypermetrin) in controlling adult tiger mosquito populations in highly populated areas. To test the effect of the two treatments pre- and post-treatment human landing rate counts were conducted for two years. After one day from the treatment we observed a 100% population decrease in mosquito abundance with both application methods and both insecticides. However, seven and 14 days after the application the stretcher sprayer showed larger population reductions than the mist sprayer. No effect of insecticide type after one day and 14 days was found, while Etox caused slightly higher population reduction than Microsin after seven days. Emergency measures to locally reduce the vector populations should adopt adulticide treatments using stretcher sprayers. However, more research is still needed to evaluate the potential negative effects of adulticide applications on non-target organisms.

Midgut of the non-hematophagous mosquito Toxorhynchites theobaldi (Diptera, Culicidae).

PubMed

Godoy, Raquel S M; Fernandes, Kenner M; Martins, Gustavo F

2015-10-30

In most mosquito species, the females require a blood-feeding for complete egg development. However, in Toxorhynchites mosquitoes, the eggs develop without blood-feeding, and both females and males exclusively feed on sugary diets. The midgut is a well-understood organ in blood-feeding mosquitoes, but little is known about it in non-blood-feeding ones. In the present study, the detailed morphology of the midgut of Toxorhynchites theobaldi were investigated using histochemical and ultrastructural methods. The midgut of female and male T. theobaldi adults consists of a long, slender anterior midgut (AMG), and a short, dilated posterior midgut (PMG). The AMG is subdivided into AMG1 (short, with folds) and AMG2 (long, without folds). Nerve branches and enteroendocrine cells are present in AMG and PMG, respectively. Compared with the PMG of blood-feeding female mosquitoes, the PMG of T. theobaldi is smaller; however, in both mosquitoes, PMG seems be the main region of food digestion and absorption, and protein secretion. The epithelial folds present in the AMG of T. theobaldi have not been reported in other mosquitoes; however, the midgut muscle organization and endocrine control of the digestion process are conserved in both T. theobaldi and blood-feeding mosquitoes.

West Nile virus in overwintering Culex mosquitoes, New York City, 2000.

PubMed Central

Nasci, R. S.; Savage, H. M.; White, D. J.; Miller, J. R.; Cropp, B. C.; Godsey, M. S.; Kerst, A. J.; Bennett, P.; Gottfried, K.; Lanciotti, R. S.

2001-01-01

After the 1999 West Nile (WN) encephalitis outbreak in New York, 2,300 overwintering adult mosquitoes were tested for WN virus by cell culture and reverse transcriptase-polymerase chain reaction. WN viral RNA and live virus were found in pools of Culex mosquitoes. Persistence in overwintering Cx. pipiens may be important in the maintenance of WN virus in the northeastern United States. PMID:11585542

Dry season ecology of Anopheles gambiae complex mosquitoes in The Gambia.

PubMed

Jawara, Musa; Pinder, Margaret; Drakeley, Chris J; Nwakanma, Davis C; Jallow, Ebrima; Bogh, Claus; Lindsay, Steve W; Conway, David J

2008-08-18

Malaria in The Gambia is highly seasonal, with transmission occurring as Anopheles gambiae s.l. populations expand during and immediately after a single annual rainy season that lasts from June to October. There has been very limited investigation of the ecology of vectors during the dry season, when numbers are very limited and distributions may be restricted. Weekly adult mosquito collections (pyrethrum spray, light trap, and search collections from rooms, as well as light trap collections from animal shelters, abandoned wells and grain stores), and artificial sentinel breeding site surveys were performed in four villages near the upper tidal and partially saline part of the Gambia River in the last four months of an annual dry season (March to June). Mosquito species were identified by morphological and DNA analysis, and ELISA assays were performed to test for Plasmodium falciparum sporozoites and human blood meal components. Adults of An. gambiae s.l. were collected throughout the period, numbers increasing towards the end of the dry season when humidity was increasing. Adult collections were dominated by An. melas (86%), with An. gambiae s.s. (10%) and An. arabiensis (3%) also present throughout. Most females collected in room search and spray collections contained blood meals, but most from light traps were unfed. None of the females tested (n = 1709) contained sporozoites. Larvae (mostly An. gambiae s.s.) were recovered from artificial sentinel breeding sites in the two villages that had freshwater pools. These two villages had the highest proportions of An. gambiae s.s. adults, and experienced the most substantial increase in proportions of An. gambiae s.s. after the onset of rains. During the dry season population minimum, An. melas was the predominant vector species, but differences among villages in availability of fresh-water breeding sites correlate with egg laying activity and relative numbers of An. gambiae s.s. adults, and with the increase in this

RNA-Seq Comparison of Larval and Adult Malpighian Tubules of the Yellow Fever Mosquito Aedes aegypti Reveals Life Stage-Specific Changes in Renal Function

PubMed Central

Li, Yiyi; Piermarini, Peter M.; Esquivel, Carlos J.; Drumm, Hannah E.; Schilkey, Faye D.; Hansen, Immo A.

2017-01-01

Introduction: The life history of Aedes aegypti presents diverse challenges to its diuretic system. During the larval and pupal life stages mosquitoes are aquatic. With the emergence of the adult they become terrestrial. This shifts the organism within minutes from an aquatic environment to a terrestrial environment where dehydration has to be avoided. In addition, female mosquitoes take large blood meals, which present an entirely new set of challenges to salt and water homeostasis. Methods: To determine differences in gene expression associated with these different life stages, we performed an RNA-seq analysis of the main diuretic tissue in A. aegypti, the Malpighian tubules. We compared transcript abundance in 4th instar larvae to that of adult females and analyzed the data with a focus on transcripts that encode proteins potentially involved in diuresis, like water and solute channels as well as ion transporters. We compared our results against the model of potassium- and sodium chloride excretion in the Malpighian tubules proposed by Hine et al. (2014), which involves at least eight ion transporters and a proton-pump. Results: We found 3,421 of a total number of 17,478 (19.6%) unique transcripts with a P < 0.05 and at least a 2.5 fold change in expression levels between the two groups. We identified two novel transporter genes that are highly expressed in the adult Malpighian tubules, which have not previously been part of the transport model in this species and may play important roles in diuresis. We also identified candidates for hypothesized sodium and chloride channels. Detoxification genes were generally higher expressed in larvae. Significance: This study represents the first comparison of Malpighian tubule transcriptomes between larval and adult A. aegypti mosquitoes, highlighting key differences in their renal systems that arise as they transform from an aquatic filter-feeding larval stage to a terrestrial, blood-feeding adult stage. PMID:28536536

Field Validation of a Transcriptional Assay for the Prediction of Age of Uncaged Aedes aegypti Mosquitoes in Northern Australia

PubMed Central

Hugo, Leon E.; Cook, Peter E.; Johnson, Petrina H.; Rapley, Luke P.; Kay, Brian H.; Ryan, Peter A.; Ritchie, Scott A.; O'Neill, Scott L.

2010-01-01

Background New strategies to eliminate dengue have been proposed that specifically target older Aedes aegypti mosquitoes, the proportion of the vector population that is potentially capable of transmitting dengue viruses. Evaluation of these strategies will require accurate and high-throughput methods of predicting mosquito age. We previously developed an age prediction assay for individual Ae. aegypti females based on the transcriptional profiles of a selection of age responsive genes. Here we conducted field testing of the method on Ae. aegypti that were entirely uncaged and free to engage in natural behavior. Methodology/Principal Findings We produced “free-range” test specimens by releasing 8007 adult Ae. aegypti inside and around an isolated homestead in north Queensland, Australia, and recapturing females at two day intervals. We applied a TaqMan probe-based assay design that enabled high-throughput quantitative RT-PCR of four transcripts from three age-responsive genes and a reference gene. An age prediction model was calibrated on mosquitoes maintained in small sentinel cages, in which 68.8% of the variance in gene transcription measures was explained by age. The model was then used to predict the ages of the free-range females. The relationship between the predicted and actual ages achieved an R2 value of 0.62 for predictions of females up to 29 days old. Transcriptional profiles and age predictions were not affected by physiological variation associated with the blood feeding/egg development cycle and we show that the age grading method could be applied to differentiate between two populations of mosquitoes having a two-fold difference in mean life expectancy. Conclusions/Significance The transcriptional profiles of age responsive genes facilitated age estimates of near-wild Ae. aegypti females. Our age prediction assay for Ae. aegypti provides a useful tool for the evaluation of mosquito control interventions against dengue where mosquito

Advances in mosquito dynamics modeling

NASA Astrophysics Data System (ADS)

Wijaya, Karunia Putra; Götz, Thomas; Soewono, Edy

2016-11-01

It is preliminarily known that Aedes mosquitoes are very close to humans and their dwellings, also give rises to a broad spectrum of diseases: dengue, yellow fever, chikungunya. In this paper, we explore a multi-age-class model for mosquito population secondarily classified into indoor-outdoor dynamics. We accentuate a novel design for the model in which periodicity of the affecting time-varying environmental condition is taken into account. Application of the optimal control with collocated measure as apposed to the widely-used prototypic smooth time-continuous measure is also considered. Using two approaches: least-square and maximum likelihood, we estimate several involving undetermined parameters. We analyze the model enforceability to biological point of view such as existence, uniqueness, positivity and boundedness of solution trajectory, also existence and stability of (non)trivial periodic solution(s) by means of the basic mosquito offspring number. Some numerical tests are brought along at the rest of the paper as a compact realistic visualization of the model.

Potential for mosquitoes (Diptera: Culicidae) from Florida to transmit rift valley fever virus

USDA-ARS?s Scientific Manuscript database

We evaluated 8 species of mosquitoes collected in Florida to determine which of these should be targeted for control should Rift Valley fever virus (RVFV) be detected in North America. Female mosquitoes that had fed on adult hamsters inoculated with RVFV were incubated for 7-21 d at 26°C, allowed to...

The effect of long-lasting insecticidal water container covers on field populations of Aedes aegypti (L.) mosquitoes in Cambodia.

PubMed

Seng, Chang Moh; Setha, To; Nealon, Joshua; Chantha, Ngan; Socheat, Doung; Nathan, Michael B

2008-12-01

Dengue in Cambodia is mainly transmitted by Aedes aegypti (L.) mosquitoes that primarily breed in large, concrete jars (> or =200 liters) used for the storage of water for domestic use. Following a preliminary risk assessment, long-lasting insecticidal netting (LN) treated with deltamethrin was incorporated into the design of the covers for these jars. Their effect on immature and adult female populations of Ae. aegypti in six villages in a peri-urban area of Cambodia were compared with populations in six nearby control villages before and for 22 weeks after distribution of the jar covers. There were significantly fewer pupae per house in intervention villages than in control villages (6.6 and 31.9, respectively, p<0.01). Fewer pupae were recovered from intervention houses than from control houses at every post-intervention assessment. Two weeks after the intervention, the average number of indoor resting female Ae. aegypti per house in the intervention villages had declined approximately three-fold, whereas in the controls there was only a slight reduction (16%). The magnitude of the difference between the two areas diminished over time, which contact bioassays confirmed was likely due to a gradual reduction of insecticidal effect of the jar covers. In the study area, insecticide-treated covers for large concrete water storage jars were efficacious for controlling Ae. aegypti in the protected water jars and with a demonstrable effect on adult densities and survival. Further studies of this targeted container strategy in Cambodia, and elsewhere, are recommended. However, improvements in technology that would extend the duration of insecticidal effectiveness of LN materials may be needed for the development of cost-effective public health applications.

Mosquito Vectors and the Globalization of Plasmodium falciparum Malaria.

PubMed

Molina-Cruz, Alvaro; Zilversmit, Martine M; Neafsey, Daniel E; Hartl, Daniel L; Barillas-Mury, Carolina

2016-11-23

Plasmodium falciparum malaria remains a devastating public health problem. Recent discoveries have shed light on the origin and evolution of Plasmodium parasites and their interactions with their vertebrate and mosquito hosts. P. falciparum malaria originated in Africa from a single horizontal transfer between an infected gorilla and a human, and became global as the result of human migration. Today, P. falciparum malaria is transmitted worldwide by more than 70 different anopheline mosquito species. Recent studies indicate that the mosquito immune system can be a barrier to malaria transmission and that the P. falciparum Pfs47 gene allows the parasite to evade mosquito immune detection. Here, we review the origin and globalization of P. falciparum and integrate this history with analysis of the biology, evolution, and dispersal of the main mosquito vectors. This new perspective broadens our understanding of P. falciparum population structure and the dispersal of important parasite genetic traits.

Mosquitoes and the environment in Nile Delta villages with previous rift valley fever activity

USDA-ARS?s Scientific Manuscript database

Egypt is affected by serious human and animal mosquito-borne diseases such as Rift Valley fever (RVF). We investigated how potential RVF virus mosquito vector populations are affected by environmental conditions in the Nile Delta region of Egypt by collecting mosquitoes and environmental data from t...

Evaluation of plant-mediated synthesized silver nanoparticles against vector mosquitoes.

PubMed

Veerakumar, Kaliyan; Govindarajan, Marimuthu; Hoti, S L

2014-12-01

Diseases transmitted by blood-feeding mosquitoes, such as dengue fever, dengue hemorrhagic fever, Japanese encephalitis, malaria, and filariasis, are increasing in prevalence, particularly in tropical and subtropical zones. To control mosquitoes and mosquito-borne diseases, which have worldwide health and economic impacts, synthetic insecticide-based interventions are still necessary, particularly in situations of epidemic outbreak and sudden increases of adult mosquitoes. Green nanoparticle synthesis has been achieved using environmentally acceptable plant extract and eco-friendly reducing and capping agents. In view of the recently increased interest in developing plant origin insecticides as an alternative to chemical insecticide, in the present study, the adulticidal activity of silver nanoparticles (AgNPs) synthesized using Heliotropium indicum plant leaf extract against adults of Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus was determined. Adult mosquitoes were exposed to varying concentrations of aqueous extract of H. indicum and synthesized AgNPs for 24 h. AgNPs were rapidly synthesized using the leaf extract of H. indicum, and the formation of nanoparticles was observed within 6 h. The results recorded from UV-vis spectrum, Fourier transform infrared, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy support the biosynthesis and characterization of AgNPs. The maximum efficacy was observed in synthesized AgNPs against the adult of A. stephensi (lethal dose (LD)₅₀ = 26.712 μg/mL; LD₉₀ = 49.061 μg/mL), A. aegypti (LD₅₀ = 29.626 μg/mL; LD₉₀ = 54.269 μg/mL), and C. quinquefasciatus (LD₅₀ = 32.077 μg/mL; LD₉₀ = 58.426 μg/mL), respectively. No mortality was observed in the control. These results suggest that the leaf aqueous extracts of H.indicum and green synthesis of AgNPs have the potential to be used as an ideal eco-friendly approach for the control of

Population Health Management for Older Adults

PubMed Central

Tkatch, Rifky; Musich, Shirley; MacLeod, Stephanie; Alsgaard, Kathleen; Hawkins, Kevin; Yeh, Charlotte S.

2016-01-01

Background: The older adult population is expanding, living longer, with multiple chronic conditions. Understanding and managing their needs over time is an integral part of defining successful aging. Population health is used to describe the measurement and health outcomes of a population. Objectives: To define population health as applied to older adults, summarize lessons learned from current research, and identify potential interventions designed to promote successful aging and improved health for this population. Method: Online search engines were utilized to identify research on population health and health interventions for older adults. Results: Population health management (PHM) is one strategy to promote the health and well-being of target populations. Interventions promoting health across a continuum tend to be disease, risk, or health behavior specific rather than encompassing a global concept of health. Conclusion: Many existing interventions for older adults are simply research based with limited generalizability; as such, further work in this area is warranted. PMID:28680938

Occurrence and Spread of the Invasive Asian Bush Mosquito Aedes japonicus japonicus (Diptera: Culicidae) in West and North Germany since Detection in 2012 and 2013, Respectively.

PubMed

Kampen, Helge; Kuhlisch, Cornelius; Fröhlich, Andreas; Scheuch, Dorothee E; Walther, Doreen

2016-01-01

The invasive Asian bush mosquito Aedes japonicus japonicus was first recognised as established in Germany in 2008. In addition to the first known and quickly expanding population in the southwestern part of the country, three separate populations were discovered in West, North and southeastern Germany in 2012, 2013 and 2015, respectively, by means of the 'Mueckenatlas', a German instrument of passive mosquito surveillance. Since the first findings of mosquito specimens in West and North Germany, these regions were checked annually for continuing colonisation and spread of the species. Both affected areas were covered by a virtual 10x10km2 grid pattern in the cells of which cemeteries were screened for immature stages of the mosquito. The cells were considered populated as soon as larvae or pupae were detected, whereas they were classified as negative when no mosquito stages were found in the cemeteries of at least three different towns or villages. Presence was also recorded when Ae. j. japonicus adults were submitted to the 'Mueckenatlas' from the respective cell or when there was evidence of local occurrence in localities other than cemeteries. Based on this approach, a significant expansion of the populated area was documented in West Germany since the first detection of Ae. j. japonicus in 2012 (increase in positive grid cells by more than 400%), while the North German population appears not to be expanding so far (reduction of positive grid cells by ca. 30% since 2013). As Ae. j. japonicus finds suitable climatic and ecological conditions in Germany, the differential expansion of the two populations might be attributed to the West German population being older and thus more firmly established than the closely related but younger North German population that might still be in its founder phase. However, geographic spread of all German populations in the future is anticipated. Continuous surveillance is recommended, as Ae. j. japonicus is a competent vector of

A highly stable blood meal alternative for rearing Aedes and Anopheles mosquitoes.

PubMed

Baughman, Ted; Peterson, Chelsea; Ortega, Corrie; Preston, Sarah R; Paton, Christopher; Williams, Jessica; Guy, Amy; Omodei, Gavin; Johnson, Brian; Williams, Helen; O'Neill, Scott L; Ritchie, Scott A; Dobson, Stephen L; Madan, Damian

2017-12-01

We investigated alternatives to whole blood for blood feeding of mosquitoes with a focus on improved stability and compatibility with mass rearing programs. In contrast to whole blood, an artificial blood diet of ATP-supplemented plasma was effective in maintaining mosquito populations and was compatible with storage for extended periods refrigerated, frozen, and as a lyophilized powder. The plasma ATP diet supported rearing of both Anopheles and Aedes mosquitoes. It was also effective in rearing Wolbachia-infected Aedes mosquitoes, suggesting compatibility with vector control efforts.

Quantitative Trait Loci Mapping of Genome Regions Controlling Permethrin Resistance in the Mosquito Aedes aegypti

PubMed Central

Saavedra-Rodriguez, Karla; Strode, Clare; Flores Suarez, Adriana; Fernandez Salas, Ildefonso; Ranson, Hilary; Hemingway, Janet; Black, William C.

2008-01-01

The mosquito Aedes aegypti is the principal vector of dengue and yellow fever flaviviruses. Permethrin is an insecticide used to suppress Ae. aegypti adult populations but metabolic and target site resistance to pyrethroids has evolved in many locations worldwide. Quantitative trait loci (QTL) controlling permethrin survival in Ae. aegypti were mapped in an F3 advanced intercross line. Parents came from a collection of mosquitoes from Isla Mujeres, México, that had been selected for permethrin resistance for two generations and a reference permethrin-susceptible strain originally from New Orleans. Following a 1-hr permethrin exposure, 439 F3 adult mosquitoes were phenotyped as knockdown resistant, knocked down/recovered, or dead. For QTL mapping, single nucleotide polymorphisms (SNPs) were identified at 22 loci with potential antixenobiotic activity including genes encoding cytochrome P450s (CYP), esterases (EST), or glutathione transferases (GST) and at 12 previously mapped loci. Seven antixenobiotic genes mapped to chromosome I, six to chromosome II, and nine to chromosome III. Two QTL of major effect were detected on chromosome III. One corresponds with a SNP previously associated with permethrin resistance in the para sodium channel gene and the second with the CCEunk7o esterase marker. Additional QTL but of relatively minor effect were also found. These included two sex-linked QTL on chromosome I affecting knockdown and recovery and a QTL affecting survival and recovery. On chromosome II, one QTL affecting survival and a second affecting recovery were detected. The patterns confirm that mutations in the para gene cause target-site insensitivity and are the major source of permethrin resistance but that other genes dispersed throughout the genome contribute to recovery and survival of mosquitoes following permethrin exposure. PMID:18723882

A novel video-tracking system to quantify the behaviour of nocturnal mosquitoes attacking human hosts in the field.

PubMed

Angarita-Jaimes, N C; Parker, J E A; Abe, M; Mashauri, F; Martine, J; Towers, C E; McCall, P J; Towers, D P

2016-04-01

Many vectors of malaria and other infections spend most of their adult life within human homes, the environment where they bloodfeed and rest, and where control has been most successful. Yet, knowledge of peri-domestic mosquito behaviour is limited, particularly how mosquitoes find and attack human hosts or how insecticides impact on behaviour. This is partly because technology for tracking mosquitoes in their natural habitats, traditional dwellings in disease-endemic countries, has never been available. We describe a sensing device that enables observation and recording of nocturnal mosquitoes attacking humans with or without a bed net, in the laboratory and in rural Africa. The device addresses requirements for sub-millimetre resolution over a 2.0 × 1.2 × 2.0 m volume while using minimum irradiance. Data processing strategies to extract individual mosquito trajectories and algorithms to describe behaviour during host/net interactions are introduced. Results from UK laboratory and Tanzanian field tests showed that Culex quinquefasciatus activity was higher and focused on the bed net roof when a human host was present, in colonized and wild populations. Both C. quinquefasciatus and Anopheles gambiae exhibited similar behavioural modes, with average flight velocities varying by less than 10%. The system offers considerable potential for investigations in vector biology and many other fields. © 2016 The Authors.

Odor Coding in the Maxillary Palp of the Malaria Vector Mosquito Anopheles gambiae

PubMed Central

Lu, Tan; Qiu, Yu Tong; Wang, Guirong; Kwon, Jae Young; Rutzler, Michael; Kwon, Hyung-Wook; Pitts, R. Jason; van Loon, Joop J.A.; Takken, Willem; Carlson, John R.; Zwiebel, Laurence J.

2011-01-01

Summary Background Many species of mosquitoes, including the major malaria vector Anopheles gambiae, utilize carbon dioxide (CO2) and 1-octen-3-ol as olfactory cues in host-seeking behaviors that underlie their vectorial capacity. However, the molecular and cellular basis of such olfactory responses remains largely unknown. Results Here, we use molecular and physiological approaches coupled with systematic functional analyses to define the complete olfactory sensory map of the An. gambiae maxillary palp, an olfactory appendage that mediates the detection of these compounds. In doing so, we identify three olfactory receptor neurons (ORNs) that are organized in stereotyped triads within the maxillary-palp capitate-peg-sensillum population. One ORN is CO2-responsive and characterized by the coexpression of three receptors that confer CO2 responses, whereas the other ORNs express characteristic odorant receptors (AgORs) that are responsible for their in vivo olfactory responses. Conclusions Our results describe a complete and highly concordant map of both the molecular and cellular olfactory components on the maxillary palp of the adult female An. gambiae mosquito. These results also facilitate the understanding of how An. gambiae mosquitoes sense olfactory cues that might be exploited to compromise their ability to transmit malaria. PMID:17764944

Mosquito-borne viruses circulating in Kinshasa, Democratic Republic of the Congo.

PubMed

Mbanzulu, Kennedy Makola; Wumba, Roger; Mukendi, Jean-Pierre Kambala; Zanga, Josué Kikana; Shija, Fortunate; Bobanga, Thierry Lengu; Aloni, Michel Ntetani; Misinzo, Gerald

2017-04-01

Diseases caused by mosquito-borne viruses are among the most important emerging diseases that threaten human and animal health, particularly in Africa. However, little attention has been paid to these diseases in the Democratic Republic of the Congo (DRC). The present cross-sectional study was undertaken between March and May 2014 to investigate the presence of mosquito-borne viruses in mosquitoes collected from five municipalities of Kinshasa, DRC. Mosquitoes were collected using BG-Sentinel traps and battery-powered aspirators. Female mosquitoes were pooled according to their genera and sampling locations, preserved in RNAlater, and later screened for viruses using reverse transcription PCR (RT-PCR) assays. A total of 2922 mosquitoes were collected and 29 pools of female mosquitoes, containing approximately 30 mosquitoes each, were tested. Twelve of the 29 (41.4%) mosquito pools were found to be infected with at least one arbovirus, with eight (27.5%) pools positive for Alphavirus, nine (31%) for Flavivirus, and five (17.2%) for Bunyaviridae. Chikungunya, o'nyong'nyong, and Rift valley fever viruses were detected. The present study shows that mosquitoes in Kinshasa carry mosquito-borne viruses that may have serious public health implications. Further investigations on the presence of mosquito-borne viruses in the human and livestock populations of Kinshasa and DRC are recommended. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Estimating malaria transmission from humans to mosquitoes in a noisy landscape.

PubMed

Reiner, Robert C; Guerra, Carlos; Donnelly, Martin J; Bousema, Teun; Drakeley, Chris; Smith, David L

2015-10-06

A basic quantitative understanding of malaria transmission requires measuring the probability a mosquito becomes infected after feeding on a human. Parasite prevalence in mosquitoes is highly age-dependent, and the unknown age-structure of fluctuating mosquito populations impedes estimation. Here, we simulate mosquito infection dynamics, where mosquito recruitment is modelled seasonally with fractional Brownian noise, and we develop methods for estimating mosquito infection rates. We find that noise introduces bias, but the magnitude of the bias depends on the 'colour' of the noise. Some of these problems can be overcome by increasing the sampling frequency, but estimates of transmission rates (and estimated reductions in transmission) are most accurate and precise if they combine parity, oocyst rates and sporozoite rates. These studies provide a basis for evaluating the adequacy of various entomological sampling procedures for measuring malaria parasite transmission from humans to mosquitoes and for evaluating the direct transmission-blocking effects of a vaccine. © 2015 The Authors.

Estimating malaria transmission from humans to mosquitoes in a noisy landscape

PubMed Central

Reiner, Robert C.; Guerra, Carlos; Donnelly, Martin J.; Bousema, Teun; Drakeley, Chris; Smith, David L.

2015-01-01

A basic quantitative understanding of malaria transmission requires measuring the probability a mosquito becomes infected after feeding on a human. Parasite prevalence in mosquitoes is highly age-dependent, and the unknown age-structure of fluctuating mosquito populations impedes estimation. Here, we simulate mosquito infection dynamics, where mosquito recruitment is modelled seasonally with fractional Brownian noise, and we develop methods for estimating mosquito infection rates. We find that noise introduces bias, but the magnitude of the bias depends on the ‘colour' of the noise. Some of these problems can be overcome by increasing the sampling frequency, but estimates of transmission rates (and estimated reductions in transmission) are most accurate and precise if they combine parity, oocyst rates and sporozoite rates. These studies provide a basis for evaluating the adequacy of various entomological sampling procedures for measuring malaria parasite transmission from humans to mosquitoes and for evaluating the direct transmission-blocking effects of a vaccine. PMID:26400195

Field Evaluation of Four Spatial Repellent Devices Against Arkansas Rice-Land Mosquitoes

DTIC Science & Technology

2014-03-01

FIELD EVALUATION OF FOUR SPATIAL REPELLENT DEVICES AGAINST ARKANSAS RICE-LAND MOSQUITOES DAVID A. DAME,1 MAX V. MEISCH,2 CAROLYN N. LEWIS,2 DANIEL L... mosquitoes to locate a host. There are many commercially available spatial repellent products currently on the market. These products include...a large rice growing area where late-spring and summer agricultural irriga- tion generates dense mosquito populations. Spatial repellent devices

Effects of lambda-cyhalothrin on mosquito larvae and predatory aquatic insects.

PubMed

Lawler, Sharon P; Dritz, Deborah A; Christiansen, Julie A; Cornel, Anthony J

2007-03-01

Agricultural insecticides can affect mosquito production in rice fields by controlling mosquitoes, disrupting biological control or contributing to selection of insecticide resistance. The duration of insecticidal activity of the pyrethroid lambda-cyhalothrin was quantified on predatory insects in rice fields and on three kinds of mosquito larva: a pyrethroid-susceptible strain of Culex tarsalis Coquillet, a pyrethroid-resistant strain of Cx pipiens L. (sensu lato) and non-resistant Cx pipiens s.l. Lambda-cyhalothrin killed most caged, susceptible mosquitoes for up to 21 days. It killed fewer resistant Cx pipiens s.l., but suppressed their survival for over a week. Lambda-cyhalothrin suppressed field populations of predatory insects through day 29. Agricultural use of lambda-cyhalothrin can provide incidental mosquito control. However, the pyrethroid persisted in sediment and gradually decreased in activity, which could contribute to selection of pyrethroid-resistant mosquitoes. Because caged mosquitoes showed good survival before predators recovered, disruption of biological control is possible. It is therefore advisable for growers and mosquito control agencies to communicate about pesticide use. Copyright 2006 Society of Chemical Industry.

Detection of Francisella tularensis in Alaskan Mosquitoes (Diptera: Culicidae) and Assessment of a Laboratory Model for Transmission

PubMed Central

TRIEBENBACH, ALISON N.; VOGL, SIGRID J.; LOTSPEICH-COLE, LEDA; SIKES, DEREK S.; HAPP, GEORGE M.; HUEFFER, KARSTEN

2013-01-01

Tularemia is a zoonotic disease caused by the Category A bioterrorism agent Francisella tularensis. In Scandinavia, tularemia transmission by mosquitoes has been widely cited in the literature. We tested >2,500 mosquitoes captured in Alaska and found Francisella DNA in 30% of pooled samples. To examine the potential for transmission of Francisella by mosquitoes, we developed a mosquito model of Francisella infection. Larvae of Anopheles gambiae Giles and Aedes aegypti (L.) readily ingest F. tularensis but do not efficiently transfer infective doses of the bacterium to the pupal or adult stage. After a bloodmeal containing Francisella, adult female An. gambiae and Ae. aegypti retained detectable levels of Francisella DNA for 3 d, but when they took a second bloodmeal, the mammalian host was not infected. This study suggests that although Francisella DNA can be detected in a significant portion of wild-caught mosquitoes, transmission of Francisella is either very inefficient or is species dependent for the Francisella strain or the arthropod vector. PMID:20695280

Mosquito repellent activity of volatile oils from selected aromatic plants.

PubMed

Lalthazuali; Mathew, Nisha

2017-02-01

Essential oils from fresh leaves of four aromatic plants viz., Ocimum sanctum, Mentha piperita, Eucalyptus globulus and Plectranthus amboinicus were extracted by hydrodistillation. The test solutions were prepared as 20% essential oil in ethanol and positive control as 20% DEET in ethanol. Essential oil blend was prepared as 5% concentration. Nulliparous, 3-5-day-old female adult Aedes aegypti mosquitoes were used for repellency screening as per ICMR protocol. The study showed that the repellency of 20% essential oil of O. sanctum, M. piperita and P. amboinicus were comparable with that of the standard DEET (20%) as no mosquito landing on the test was observed up to 6 h. The E. globulus oil exhibited mosquito repellency only upto 1½ h. Considerable mosquito landing and feeding was displayed in negative control. In the case of the oil blend, no landing of mosquitoes was seen up to 6 h as that of positive control. The results showed that the essential oil blend from O. sanctum, M. piperita, E. globulus and P. amboinicus could repel Ae. aegypti mosquitoes or prevent from feeding as in the case of DEET even at a lower concentration of 5%. This study demonstrates the potential of essential oils from O. sanctum, M. piperita, E. globulus and P. amboinicus and their blend as mosquito repellents against Ae. aegypti, the vector of dengue, chikungunya and yellow fever.

Biodiversity and ecosystem risks arising from using guppies to control mosquitoes

PubMed Central

Frauendorf, Therese C.; Marques, Piata S.; Mackenzie, Richard A.; Manna, Luisa R.; Mazzoni, Rosana; Phillip, Dawn A. T.; Warbanski, Misha L.; Zandonà, Eugenia

2016-01-01

Deploying mosquito predators such as the guppy (Poecilia reticulata) into bodies of water where mosquitoes breed is a common strategy for limiting the spread of disease-carrying mosquitoes. Here, we draw on studies from epidemiology, conservation, ecology and evolution to show that the evidence for the effectiveness of guppies in controlling mosquitoes is weak, that the chances of accidental guppy introduction into local ecosystems are large, and that guppies can easily establish populations and damage these aquatic ecosystems. We highlight several knowledge and implementation gaps, and urge that this approach is either abandoned in favour of more effective strategies or that it is used much more rigorously. Controlling mosquitoes does not need to come at the expense of freshwater biodiversity. PMID:28120806

Commensal Viruses of Mosquitoes: Host Restriction, Transmission, and Interaction with Arboviral Pathogens

PubMed Central

Hall, Roy A.; Bielefeldt-Ohmann, Helle; McLean, Breeanna J.; O’Brien, Caitlin A.; Colmant, Agathe M.G.; Piyasena, Thisun B.H.; Harrison, Jessica J.; Newton, Natalee D.; Barnard, Ross T.; Prow, Natalie A.; Deerain, Joshua M.; Mah, Marcus G.K.Y.; Hobson-Peters, Jody

2016-01-01

Recent advances in virus detection strategies and deep sequencing technologies have enabled the identification of a multitude of new viruses that persistently infect mosquitoes but do not infect vertebrates. These are usually referred to as insect-specific viruses (ISVs). These novel viruses have generated considerable interest in their modes of transmission, persistence in mosquito populations, the mechanisms that restrict their host range to mosquitoes, and their interactions with pathogens transmissible by the same mosquito. In this article, we discuss studies in our laboratory and others that demonstrate that many ISVs are efficiently transmitted directly from the female mosquito to their progeny via infected eggs, and, moreover, that persistent infection of mosquito cell cultures or whole mosquitoes with ISVs can restrict subsequent infection, replication, and transmission of some mosquito-borne viral pathogens. This suggests that some ISVs may act as natural regulators of arboviral transmission. We also discuss viral and host factors that may be responsible for their host restriction. PMID:28096646

Gene Silencing in Adult Aedes aegypti Mosquitoes Through Oral Delivery of Double-Stranded RNA

DTIC Science & Technology

2012-01-01

utilization of dsRNA as a bio-insecticide against mosquitoes has only recently begun to be evaluated. Double-stranded RNA targeting chitin syn- thase...double- stranded RNA nanoparticle-mediated RNA interference to silence chitin synthase genes through larval feeding in the African malaria mosquito

The effect of pesticide residue on caged mosquito bioassays.

PubMed

Barber, J A S; Greer, Mike; Coughlin, Jamie

2006-09-01

Wind tunnel experiments showed that secondary pickup of insecticide residue by mosquitoes in cage bioassays had a significant effect on mortality. Cage bioassays using adult Ochlerotatus taeniorhynchus (Wiedemann) investigated the effect of exposure time to a contaminated surface. Cages were dosed in a wind tunnel using the LC50 for naled (0.124 mg a.i./ml) and an LC25 (0.0772 mg a.i./ml) for naled. Half of the bioassay mosquitoes were moved directly into clean cages with the other half remaining in the sprayed, hence contaminated, cage. Treatment mortality was assessed at 8, 15, 30, 60, 120, 240, and 1,440 min postapplication. Cage contamination had a significant effect on mosquito mortality for both the LC25 and LC50 between 15 and 30 min postapplication.

Effects of Organic Amendments on Microbiota Associated with the Culex nigripalpus Mosquito Vector of the Saint Louis Encephalitis and West Nile Viruses.

PubMed

Duguma, Dagne; Hall, Michael W; Smartt, Chelsea T; Neufeld, Josh D

2017-01-01

Pollution from nutrients in aquatic habitats has been linked to increases in disease vectors, including mosquitoes and other pestiferous insects. One possibility is that changes in mosquito microbiomes are impacted by nutrient enrichments and that these changes affect various traits, including larval development, susceptibility to larval control agents, and susceptibility of the adult mosquitoes to pathogens. We tested this hypothesis using field mesocosms supplemented with low- and high-organic-nutrient regimens and then sampled microbial communities associated with the naturally colonizing Culex nigripalpus mosquito vector. By high-throughput sequencing of 16S rRNA gene sequences, we found no significant differences in overall microbial communities associated with sampled mosquitoes, despite detecting discernible differences in environmental variables, including pH, dissolved oxygen, and nutrient amendments. Nevertheless, indicator species analysis revealed that members of the Clostridiales were significantly associated with mosquitoes that originated from high-nutrient enrichments. In contrast, members of the Burkholderiales were associated with mosquitoes from the low-nutrient enrichment. High bacterial variability associated with the life stages of the C. nigripalpus was largely unaffected by levels of nutrient enrichments that impacted larval microbial resources, including bacteria, ciliates, and flagellates in the larval environments. IMPORTANCE Mosquito microbiota provide important physiological and ecological attributes to mosquitoes, including an impact on their susceptibility to pathogens, fitness, and sensitivity to mosquito control agents. Culex nigripalpus mosquito populations transmit various pathogens, including the Saint Louis and West Nile viruses, and proliferate in nutrient-rich environments, such as in wastewater treatment wetlands. Our study examined whether increases in nutrients within larval mosquito developmental habitats impact microbial

Direct PCR of indigenous and invasive mosquito species: a time- and cost-effective technique of mosquito barcoding.

PubMed

Werblow, A; Flechl, E; Klimpel, S; Zittra, C; Lebl, K; Kieser, K; Laciny, A; Silbermayr, K; Melaun, C; Fuehrer, H-P

2016-03-01

Millions of people die each year as a result of pathogens transmitted by mosquitoes. However, the morphological identification of mosquito species can be difficult even for experts. The identification of morphologically indistinguishable species, such as members of the Anopheles maculipennis complex (Diptera: Culicidae), and possible hybrids, such as Culex pipiens pipiens/Culex pipiens molestus (Diptera: Culicidae), presents a major problem. In addition, the detection and discrimination of newly introduced species can be challenging, particularly to researchers without previous experience. Because of their medical importance, the clear identification of all relevant mosquito species is essential. Using the direct polymerase chain reaction (PCR) method described here, DNA amplification without prior DNA extraction is possible and thus species identification after sequencing can be achieved. Different amounts of tissue (leg, head; larvae or adult) as well as different storage conditions (dry, ethanol, -20 and -80 °C) and storage times were successfully applied and showed positive results after amplification and gel electrophoresis. Overall, 28 different indigenous and non-indigenous mosquito species were analysed using a gene fragment of the COX1 gene for species differentiation and identification by sequencing this 658-bp fragment. Compared with standard PCR, this method is time- and cost-effective and could thus improve existing surveillance and control programmes. © 2015 The Authors. Medical and Veterinary Entomology published by John Wiley & Sons Ltd on behalf of Royal Entomological Society.

Potential impacts of climate change on the ecology of dengue and its mosquito vector the Asian tiger mosquito (Aedes albopictus)

NASA Astrophysics Data System (ADS)

Erickson, R. A.; Hayhoe, K.; Presley, S. M.; Allen, L. J. S.; Long, K. R.; Cox, S. B.

2012-09-01

Shifts in temperature and precipitation patterns caused by global climate change may have profound impacts on the ecology of certain infectious diseases. We examine the potential impacts of climate change on the transmission and maintenance dynamics of dengue, a resurging mosquito-vectored infectious disease. In particular, we project changes in dengue season length for three cities: Atlanta, GA; Chicago, IL and Lubbock, TX. These cities are located on the edges of the range of the Asian tiger mosquito within the United States of America and were chosen as test cases. We use a disease model that explicitly incorporates mosquito population dynamics and high-resolution climate projections. Based on projected changes under the Special Report on Emissions Scenarios (SRES) A1fi (higher) and B1 (lower) emission scenarios as simulated by four global climate models, we found that the projected warming shortened mosquito lifespan, which in turn decreased the potential dengue season. These results illustrate the difficulty in predicting how climate change may alter complex systems.

British Container Breeding Mosquitoes: The Impact of Urbanisation and Climate Change on Community Composition and Phenology

PubMed Central

Townroe, Susannah; Callaghan, Amanda

2014-01-01

The proliferation of artificial container habitats in urban areas has benefitted urban adaptable mosquito species globally. In areas where mosquitoes transmit viruses and parasites, it can promote vector population productivity and fuel mosquito-borne disease outbreaks. In Britain, storage of water in garden water butts is increasing, potentially expanding mosquito larval habitats and influencing population dynamics and mosquito-human contact. Here we show that the community composition, abundance and phenology of mosquitoes breeding in experimental water butt containers were influenced by urbanisation. Mosquitoes in urban containers were less species-rich but present in significantly higher densities (100.4±21.3) per container than those in rural containers (77.7±15.1). Urban containers were dominated by Culex pipiens (a potential vector of West Nile Virus [WNV]) and appear to be increasingly exploited by Anopheles plumbeus (a human-biting potential WNV and malaria vector). Culex phenology was influenced by urban land use type, with peaks in larval abundances occurring earlier in urban than rural containers. Among other factors, this was associated with an urban heat island effect which raised urban air and water temperatures by 0.9°C and 1.2°C respectively. Further increases in domestic water storage, particularly in urban areas, in combination with climate changes will likely alter mosquito population dynamics in the UK. PMID:24759617

British container breeding mosquitoes: the impact of urbanisation and climate change on community composition and phenology.

PubMed

Townroe, Susannah; Callaghan, Amanda

2014-01-01

The proliferation of artificial container habitats in urban areas has benefitted urban adaptable mosquito species globally. In areas where mosquitoes transmit viruses and parasites, it can promote vector population productivity and fuel mosquito-borne disease outbreaks. In Britain, storage of water in garden water butts is increasing, potentially expanding mosquito larval habitats and influencing population dynamics and mosquito-human contact. Here we show that the community composition, abundance and phenology of mosquitoes breeding in experimental water butt containers were influenced by urbanisation. Mosquitoes in urban containers were less species-rich but present in significantly higher densities (100.4±21.3) per container than those in rural containers (77.7±15.1). Urban containers were dominated by Culex pipiens (a potential vector of West Nile Virus [WNV]) and appear to be increasingly exploited by Anopheles plumbeus (a human-biting potential WNV and malaria vector). Culex phenology was influenced by urban land use type, with peaks in larval abundances occurring earlier in urban than rural containers. Among other factors, this was associated with an urban heat island effect which raised urban air and water temperatures by 0.9°C and 1.2°C respectively. Further increases in domestic water storage, particularly in urban areas, in combination with climate changes will likely alter mosquito population dynamics in the UK.

Mosquito control insecticides: a probabilistic ecological risk assessment on drift exposures of naled, dichlorvos (naled metabolite) and permethrin to adult butterflies.

PubMed

Hoang, T C; Rand, G M

2015-01-01

A comprehensive probabilistic terrestrial ecological risk assessment (ERA) was conducted to characterize the potential risk of mosquito control insecticide (i.e., naled, it's metabolite dichlorvos, and permethrin) usage to adult butterflies in south Florida by comparing the probability distributions of environmental exposure concentrations following actual mosquito control applications at labeled rates from ten field monitoring studies with the probability distributions of butterfly species response (effects) data from our laboratory acute toxicity studies. The overlap of these distributions was used as a measure of risk to butterflies. The long-term viability (survival) of adult butterflies, following topical (thorax/wings) exposures was the environmental value we wanted to protect. Laboratory acute toxicity studies (24-h LD50) included topical exposures (thorax and wings) to five adult butterfly species and preparation of species sensitivity distributions (SSDs). The ERA indicated that the assessment endpoint of protection, of at least 90% of the species, 90% of the time (or the 10th percentile from the acute SSDs) from acute naled and permethrin exposures, is most likely not occurring when considering topical exposures to adults. Although the surface areas for adulticide exposures are greater for the wings, exposures to the thorax provide the highest potential for risk (i.e., SSD 10th percentile is lowest) for adult butterflies. Dichlorvos appeared to present no risk. The results of this ERA can be applied to other areas of the world, where these insecticides are used and where butterflies may be exposed. Since there are other sources (e.g., agriculture) of pesticides in the environment, where butterfly exposures will occur, the ERA may under-estimate the potential risks under real-world conditions. Copyright © 2014 Elsevier B.V. All rights reserved.

Design for mosquito abundance, diversity, and phenology sampling within the National Ecological Observatory Network

USGS Publications Warehouse

Hoekman, D.; Springer, Yuri P.; Barker, C.M.; Barrera, R.; Blackmore, M.S.; Bradshaw, W.E.; Foley, D. H.; Ginsberg, Howard; Hayden, M. H.; Holzapfel, C. M.; Juliano, S. A.; Kramer, L. D.; LaDeau, S. L.; Livdahl, T. P.; Moore, C. G.; Nasci, R.S.; Reisen, W.K.; Savage, H. M.

2016-01-01

The National Ecological Observatory Network (NEON) intends to monitor mosquito populations across its broad geographical range of sites because of their prevalence in food webs, sensitivity to abiotic factors and relevance for human health. We describe the design of mosquito population sampling in the context of NEON’s long term continental scale monitoring program, emphasizing the sampling design schedule, priorities and collection methods. Freely available NEON data and associated field and laboratory samples, will increase our understanding of how mosquito abundance, demography, diversity and phenology are responding to land use and climate change.

Infection of Laboratory-Colonized Anopheles darlingi Mosquitoes by Plasmodium vivax

PubMed Central

Moreno, Marta; Tong, Carlos; Guzmán, Mitchel; Chuquiyauri, Raul; Llanos-Cuentas, Alejandro; Rodriguez, Hugo; Gamboa, Dionicia; Meister, Stephan; Winzeler, Elizabeth A.; Maguina, Paula; Conn, Jan E.; Vinetz, Joseph M.

2014-01-01

Anopheles darlingi Root is the most important malaria vector in the Amazonia region of South America. However, continuous propagation of An. darlingi in the laboratory has been elusive, limiting entomological, genetic/genomic, and vector–pathogen interaction studies of this mosquito species. Here, we report the establishment of an An. darlingi colony derived from wild-caught mosquitoes obtained in the northeastern Peruvian Amazon region of Iquitos in the Loreto Department. We show that the numbers of eggs, larvae, pupae, and adults continue to rise at least to the F6 generation. Comparison of feeding Plasmodium vivax ex vivo of F4 and F5 to F1 generation mosquitoes showed the comparable presence of oocysts and sporozoites, with numbers that corresponded to blood-stage asexual parasitemia and gametocytemia, confirming P. vivax vectorial capacity in the colonized mosquitoes. These results provide new avenues for research on An. darlingi biology and study of An. darlingi–Plasmodium interactions. PMID:24534811

Infection of laboratory-colonized Anopheles darlingi mosquitoes by Plasmodium vivax.

PubMed

Moreno, Marta; Tong, Carlos; Guzmán, Mitchel; Chuquiyauri, Raul; Llanos-Cuentas, Alejandro; Rodriguez, Hugo; Gamboa, Dionicia; Meister, Stephan; Winzeler, Elizabeth A; Maguina, Paula; Conn, Jan E; Vinetz, Joseph M

2014-04-01

Anopheles darlingi Root is the most important malaria vector in the Amazonia region of South America. However, continuous propagation of An. darlingi in the laboratory has been elusive, limiting entomological, genetic/genomic, and vector-pathogen interaction studies of this mosquito species. Here, we report the establishment of an An. darlingi colony derived from wild-caught mosquitoes obtained in the northeastern Peruvian Amazon region of Iquitos in the Loreto Department. We show that the numbers of eggs, larvae, pupae, and adults continue to rise at least to the F6 generation. Comparison of feeding Plasmodium vivax ex vivo of F4 and F5 to F1 generation mosquitoes showed the comparable presence of oocysts and sporozoites, with numbers that corresponded to blood-stage asexual parasitemia and gametocytemia, confirming P. vivax vectorial capacity in the colonized mosquitoes. These results provide new avenues for research on An. darlingi biology and study of An. darlingi-Plasmodium interactions.

Characterizing the relationship between Asian tiger mosquito abundance and habitat in urban New Jersey

NASA Astrophysics Data System (ADS)

Ferwerda, Carolin

2009-12-01

Since its introduction to North America in 1987, the Asian tiger mosquito (Aedes albopictus) has spread rapidly. Due to its unique ecology and preference for container breeding sites, Ae. albopictus commonly inhabits urban/suburban areas and is often in close contact with humans. An aggressive pest, this mosquito species is a vector of multiple arboviruses. In order for mosquito control efforts to remain effective, control of this important vector must be guided by spatially explicit habitat models that aid in predicting mosquito outbreaks. Using linear regression, I determined the relationship between adult Ae. albopictus abundance and climate, census, and land use factors in nine urban/suburban study sites in central New Jersey. Systematically collected adult counts (females and males) from July to October 2008, served as estimates of abundance. Fine-scale land use/land cover data were obtained from object-oriented classifications of 2007 CIR orthophotos in Definiens eCognition. Mosquito abundance data were tested for spatial autocorrelation via Moran's I, semivariograms, and hotspot analysis in order to reveal consistent patterns in abundance. Spatial pattern analysis produced little evidence of consistent spatial autocorrelation, though several sites exhibited recurring hotspots, especially in areas near residential housing and vegetation. Stepwise multiple regression was able to explain 20-25 percent of variation in Ae. albopictus abundance at the 'backyard' or cell level and 72-78 percent of variation in abundance at the 'neighborhood' or study site level. Meteorological variables (temperature on the trap date and precipitation), census variables (vacant housing units and population density), and more detailed land use/land cover classes (deciduous woody vegetation, rights-of-way and vacant lots) were frequently selected in all eight models, though many other independent variables were included in the individual models. The results of the spatial statistics

Agricultural chemicals: life changer for mosquito vectors in agricultural landscapes?

PubMed

Kibuthu, Tabitha W; Njenga, Sammy M; Mbugua, Amos K; Muturi, Ephantus J

2016-09-13

Although many mosquito species develop within agricultural landscapes where they are potentially exposed to agricultural chemicals (fertilizers and pesticides), the effects of these chemicals on mosquito biology remain poorly understood. This study investigated the effects of sublethal concentrations of four agricultural chemicals on the life history traits of Anopheles arabiensis and Culex quinquefasciatus mosquitoes. Field and laboratory experiments were conducted to examine how sublethal concentrations of four agricultural chemicals: an insecticide (cypermethrin), a herbicide (glyphosate), and two nitrogenous fertilizers (ammonium sulfate and diammonium phosphate) alter oviposition site selection, emergence rates, development time, adult body size, and longevity of An. arabiensis and Cx. quinquefasciatus. Both mosquito species had preference to oviposit in fertilizer treatments relative to pesticide treatments. Emergence rates for An. arabiensis were significantly higher in the control and ammonium sulfate treatments compared to cypermethrin treatment, while emergence rates for Cx. quinquefasciatus were significantly higher in the diammonium phosphate treatment compared to glyphosate and cypermethrin treatments. For both mosquito species, individuals from the ammonium sulfate and diammonium phosphate treatments took significantly longer time to develop compared to those from cypermethrin and glyphosate treatments. Although not always significant, males and females of both mosquito species tended to be smaller in the ammonium sulfate and diammonium phosphate treatments compared to cypermethrin and glyphosate treatments. There was no significant effect of the agrochemical treatments on the longevity of either mosquito species. These results demonstrate that the widespread use of agricultural chemicals to enhance crop production can have unexpected effects on the spatial distribution and abundance of mosquito vectors of malaria and lymphatic filariasis.

Modulation of Host Learning in Aedes aegypti Mosquitoes.

PubMed

Vinauger, Clément; Lahondère, Chloé; Wolff, Gabriella H; Locke, Lauren T; Liaw, Jessica E; Parrish, Jay Z; Akbari, Omar S; Dickinson, Michael H; Riffell, Jeffrey A

2018-02-05

How mosquitoes determine which individuals to bite has important epidemiological consequences. This choice is not random; most mosquitoes specialize in one or a few vertebrate host species, and some individuals in a host population are preferred over others. Mosquitoes will also blood feed from other hosts when their preferred is no longer abundant, but the mechanisms mediating these shifts between hosts, and preferences for certain individuals within a host species, remain unclear. Here, we show that olfactory learning may contribute to Aedes aegypti mosquito biting preferences and host shifts. Training and testing to scents of humans and other host species showed that mosquitoes can aversively learn the scent of specific humans and single odorants and learn to avoid the scent of rats (but not chickens). Using pharmacological interventions, RNAi, and CRISPR gene editing, we found that modification of the dopamine-1 receptor suppressed their learning abilities. We further show through combined electrophysiological and behavioral recordings from tethered flying mosquitoes that these odors evoke changes in both behavior and antennal lobe (AL) neuronal responses and that dopamine strongly modulates odor-evoked responses in AL neurons. Not only do these results provide direct experimental evidence that olfactory learning in mosquitoes can play an epidemiological role, but collectively, they also provide neuroanatomical and functional demonstration of the role of dopamine in mediating this learning-induced plasticity, for the first time in a disease vector insect. Copyright © 2017 Elsevier Ltd. All rights reserved.

Avian Plasmodium infection in field-collected mosquitoes during 2012-2013 in Tarlac, Philippines.

PubMed

Chen, Tien-Huang; Aure, Wilfredo E; Cruz, Estrella Irlandez; Malbas, Fedelino F; Teng, Hwa-Jen; Lu, Liang-Chen; Kim, Kyeong Soon; Tsuda, Yoshio; Shu, Pei-Yun

2015-12-01

Global warming threatens to increase the spread and prevalence of mosquito-transmitted diseases. Certain pathogens may be carried by migratory birds and transmitted to local mosquito populations. Mosquitoes were collected in the northern Philippines during bird migration seasons to detect avian malaria parasites as well as for the identification of potential vector species and the estimation of infections among local mosquito populations. We used the nested PCR to detect the avian malaria species. Culex vishnui (47.6%) was the most abundant species collected and Cx. tritaeniorhynchus (13.8%) was the second most abundant. Avian Plasmodium parasites were found in eight mosquito species, for which the infection rates were between 0.5% and 6.2%. The six Plasmodium genetic lineages found in this study included P. juxtanucleare -GALLUS02, Tacy7 (Donana04), CXBIT01, Plasmodium species LIN2 New Zealand, and two unclassified lineages. The potential mosquito vectors for avian Plasmodium parasites in the Philippines were Cq. crassipes, Cx. fuscocephala, Cx. quinquefasciatus, Cx. sitiens, Cx. vishnui, and Ma. Uniformis; two major genetic lineages, P. juxtanucleare and Tacy7, were identified. © 2015 The Society for Vector Ecology.

On the analysis of parasite effect for Aedes aegypti and Aedes albopictus population

NASA Astrophysics Data System (ADS)

Kallista, Meta; Aldila, Dipo; Nuraini, Nuning; Soewono, Edy

2014-03-01

It has been reported in some countries that the population of Aedes aegypti has been significantly reduced by the invasion of Aedes albopictus. There has been a hypothesis explaining this phenomenon of which investigated the influence of parasites pathogenesis to the competition between these two mosquito species in the fields. Ascogregarina taiwanensis and Ascogregarina culicis are known as parasites that infect Aedes albopictus and Aedes aegypti, respectively. Several studies have concluded that Ascogregarina taiwanensis caused high fatality for Aedes aegypti larvae, but Ascogregarina culicis was not pathogenic to Aedes albopictus larvae. Therefore, Ascogregarina taiwanensis may contribute to reduce the number of populations Aedes aegypti in the fields. Inspired by these facts, a mathematical model depicting interaction between parasites and mosquitoes is constructed in this paper. In this model are included six dynamic mosquito compartments, i.e. egg, larvae, infected larvae, adult, infected adult and one dynamic compartment for parasite. Derivation of the existence criteria and the stability analysis of parasite-free equilibrium as well as the basic offspring for the model are presented. Numerical simulations for sensitivity analysis indicating the invasive species for variation parameters are shown.

Mosquito and Blackfly Category Manual.

ERIC Educational Resources Information Center

Bowman, James S.; And Others

This manual provides information needed to meet the standards for pesticide applicator certification. Section one is concerned with the morphology, life cycle and breeding areas of mosquitoes and the diseases resulting from their presence. The second section covers similar categories in relation to the black fly population. Calculation methods and…

Population dynamics of Aedes aegypti and dengue as influenced by weather and human behavior in San Juan, Puerto Rico.

PubMed

Barrera, Roberto; Amador, Manuel; MacKay, Andrew J

2011-12-01

Previous studies on the influence of weather on Aedes aegypti dynamics in Puerto Rico suggested that rainfall was a significant driver of immature mosquito populations and dengue incidence, but mostly in the drier areas of the island. We conducted a longitudinal study of Ae. aegypti in two neighborhoods of the metropolitan area of San Juan city, Puerto Rico where rainfall is more uniformly distributed throughout the year. We assessed the impacts of rainfall, temperature, and human activities on the temporal dynamics of adult Ae. aegypti and oviposition. Changes in adult mosquitoes were monitored with BG-Sentinel traps and oviposition activity with CDC enhanced ovitraps. Pupal surveys were conducted during the drier and wetter parts of the year in both neighborhoods to determine the contribution of humans and rains to mosquito production. Mosquito dynamics in each neighborhood was compared with dengue incidence in their respective municipalities during the study. Our results showed that: 1. Most pupae were produced in containers managed by people, which explains the prevalence of adult mosquitoes at times when rainfall was scant; 2. Water meters were documented for the first time as productive habitats for Ae. aegypti; 3. Even though Puerto Rico has a reliable supply of tap water and an active tire recycling program, water storage containers and discarded tires were important mosquito producers; 4. Peaks in mosquito density preceded maximum dengue incidence; and 5. Ae. aegypti dynamics were driven by weather and human activity and oviposition was significantly correlated with dengue incidence.

Does targeting key-containers effectively reduce Aedes aegypti population density?

PubMed

Maciel-de-Freitas, Rafael; Lourenço-de-Oliveira, Ricardo

2011-08-01

The elimination of Aedes aegypti breeding sites has been broadly adopted worldwide to keep vector population density below a critical threshold. We observed the effectiveness of targeting the most productive containers on adult A. aegypti females density, which was evaluated weekly. Adult mosquitoes were collected weekly over 55 weeks and pupal surveys were done in intervals of 4 months to determine container productivity and guidelines for interventions. Pupal surveys indicated that water tanks (72% of pupae in first survey) and metal drums (30.7% of pupae in second survey) were the most productive container types. We observed a dramatic but short-term decrease in weekly adult female A. aegypti density after covering 733 water tanks with nylon net. A long-term decrease in female adult population density was achieved only when we covered both water tanks and metal drums. Overall, pupae abundance and pupae standing crop diminished after netting water tanks and metal drums. Pupae per person, per hectare and per house decreased gradually between the first and the third pupal surveys, suggesting that targeting the most productive container types (water tanks and metal drums) produced a reduction in adult population density and infestation levels. Overall, targeting the most productive container types caused the adult mosquito density to decrease over time, supporting the assumption that this intervention is an effective tool for dengue control. However, this effect was observed only when both water tanks and metal drums were covered, possibly due to the functional similarity between these container types, which are large, often shaded, perennial water storage containers. © 2011 Blackwell Publishing Ltd.

Area-wide management of Aedes albopictus: choice of study sites based on geospatial characteristics, socioeconomic factors, and mosquito populations

USDA-ARS?s Scientific Manuscript database

Aedes (Stegomyia) albopictus (Skuse), the Asian tiger mosquito, is an introduced invasive species in the U.S. responsible for a significant proportion of service requests to local mosquito control programs. This container-utilizing mosquito is refractory to standard mosquito abatement measures in th...

First record of the Asian bush mosquito, Aedes japonicus japonicus, in Italy: invasion from an established Austrian population.

PubMed

Seidel, Bernhard; Montarsi, Fabrizio; Huemer, Hartwig P; Indra, Alexander; Capelli, Gioia; Allerberger, Franz; Nowotny, Norbert

2016-05-16

In 2011 we identified the Asian bush mosquito, Aedes japonicus japonicus (Theobald, 1901) (Diptera: Culicidae) for the first time in northern Slovenia and in the bordering Austrian federal state of Styria. Between May and July 2012 the distribution area of Ae. j. japonicus was already found to be extended westwards into Carinthia and eastwards towards Burgenland and bordering Hungary. In August 2012 the species was first detected in a western province of Hungary. In subsequent years, follow-up field studies demonstrated an active spread westwards throughout Carinthia, reaching the border to northern Italy. In July 2015 several aquatic-stage specimens of the species were discovered at three different sites in the Friuli Venezia Giulia region, north-eastern Italy. In September 2015, co-occurrence of Ae. j. japonicus and Aedes albopictus (Skuse, 1895) was observed in the same sample in that region. Ae. j. japonicus actively extended its geographic range from an established population in Carinthia (Austria) southwards to northern Italy by crossing Alpine ranges. Since Ae. albopictus and Aedes koreicus (Edwards, 1917) are already well established in northern Italy, it will be pivotal to monitor the consequences of a third invasive mosquito species trying to populate the same geographic region.

Effect of Novaluron (Rimon 10 EC) on the mosquitoes Anopheles albimanus, Anopheles pseudopunctipennis, Aedes aegypti, Aedes albopictus and Culex quinquefasciatus from Chiapas, Mexico.

PubMed

Arredondo-Jiménez, J I; Valdez-Delgado, K M

2006-12-01

Dengue fever is a serious problem in Mexico and vector control has not been effective enough at preventing outbreaks. Malaria is largely under control, but it is important that new control measures continue to be developed. Novaluron, a novel host-specific insect growth regulator and chitin synthesis inhibitor, has proved to be effective against agricultural pests, but its efficacy against larval mosquito vectors under field conditions remains unknown. In accordance with the World Health Organization Pesticide Evaluation Scheme, phase I, II and III studies were conducted to evaluate the efficacy and residual effect of Novaluron (Rimon 10 EC, Makhteshim, Beer-Sheva, Israel) on the malaria vectors Anopheles albimanus Wiedemann (Diptera: Culicidae) and Anopheles pseudopunctipennis Theobald, the dengue vectors Aedes aegypti (L) and Aedes albopictus Skuse and the nuisance mosquito Culex quinquefasciatus Say. Laboratory susceptibility tests yielded diagnostic concentrations for all five target species. Field trials to identify the optimum field dosage of Novaluron against Anopheles mosquitoes were carried out under semi-natural conditions in artificial plots and in vessels with wild mosquitoes. Efficacy was measured by monitoring mortality of larvae and pupae and the percentage of inhibition of emergence from floating cages. Dosages of Novaluron for field tests were based on pupal LC(99) (lethal concentration 99%) of An. pseudopunctipennis (0.166 mg/L) in plots and average pupal LC(99) of Ae. aegypti and Ae. albopictus (0.55 mg/L). At all dosages tested, Novaluron significantly reduced larval populations of An. albimanus, Culex coronator Dyar & Knab, Ae. albopictus and Cx. quinquefasciatus by approximately 90%, inhibited adult emergence of An. albimanus and An. pseudopunctipennis by approximately 97% for almost 4 months in experimental plots, and inhibited adult emergence of Ae. aegypti and Ae. albopictus by approximately 97% for up to 14 weeks. Recommended dosages of

Direct and Indirect Effects of Animal Detritus on Growth, Survival, and Mass of Invasive Container Mosquito Aedes albopictus (Diptera: Culicidae)

PubMed Central

YEE, DONALD A.; KESAVARAJU, BANUGOPAN; JULIANO, STEVEN A.

2007-01-01

Compared with plant detritus, animal detritus yields higher growth rates, survival, adult mass, and population growth of container-dwelling mosquitoes. It is unclear whether the benefit from animal detritus to larvae results from greater microorganism growth, direct ingestion of animal detritus by larvae, or some other mechanism. We tested alternative mechanisms by which animal detritus may benefit the invasive container-dwelling mosquito Aedesalbopictus (Skuse) (Diptera: Culicidae). In the laboratory, larvae were reared under three conditions with access to 1) detritus, but where microorganisms in the water column were reduced through periodic flushing; 2) water column microorganisms, but larvae had no direct access to detritus; or 3) both water column microorganisms and detritus. Access treatments were conducted for three masses of animal detritus: 0.005, 0.010, and 0.020 g. Water column bacterial productivity (measured via incorporation of [3H]leucine) decreased significantly with flushing and with larval presence. Removing microorganisms through flushing significantly reduced mass of adult mosquitoes (both sexes), and it significantly prolonged developmental times of females compared with treatments where water column microorganisms or microorganisms and detritus were available. Survival to adulthood was greatest when larvae had access to both water column microorganisms and 0.020 g of detritus, but it declined when only water column microorganisms were available or when 0.005 g of detritus was used. These findings indicate both direct (as a food source) and indirect (assisting with decomposition of detritus) roles of microorganisms in producing the benefit of animal detritus to container mosquito larvae. PMID:17695011

An analysis of community perceptions of mosquito-borne disease control and prevention in Sint Eustatius, Caribbean Netherlands

PubMed Central

Leslie, Teresa E.; Carson, Marianne; van Coeverden, Els; De Klein, Kirsten; Braks, Marieta; Krumeich, Anja

2017-01-01

ABSTRACT Background: In the Caribbean, mosquito-borne diseases are a public health threat. In Sint Eustatius, dengue, Chikungunya and Zika are now endemic. To control and prevent mosquito-borne diseases, the Sint Eustatius Public Health Department relies on the community to assist with the control of Aedes aegypti mosquito. Unfortunately, community based interventions are not always simple, as community perceptions and responses shape actions and influence behavioural responses Objective: The aim of this study was to determine how the Sint Eustatius population perceives the Aedes aegypti mosquito, mosquito-borne diseases and prevention and control measures and hypothesized that increased knowledge of the virus, vector, control and prevention should result in a lower AQ1 prevalence and incidence of mosquito-borne diseases. Methods: This study was conducted in Sint Eustatius island in the Eastern Caribbean. We combined qualitative and quantitative designs. We conducted interviews and focus groups discussions among community member and health professional in 2013 and 2015. We also conducted cross-sectional survey to assess local knowledge on the vector, virus, and control and prevention. Results: The population is knowledgeable; ©however, mosquito-borne diseases are not the highest health priority. While local knowledge is sometimes put into action, it happens on the 20 household/individual level as opposed to the community level. After the 2014 CHIK outbreak, there was an increase in knowledge about mosquito control and mosquito-borne diseases. Discussion: In the context of Sint Eustatius, when controlling the Aedes population it may be a strategic option to focus on the household level rather than the community and build collaborations with households by supporting them when they actively practice mosquito 25 control. To further increase the level of knowledge on the significance of mosquito-borne diseases, it may also be an option to contextualize the issue of the

An analysis of community perceptions of mosquito-borne disease control and prevention in Sint Eustatius, Caribbean Netherlands.

PubMed

Leslie, Teresa E; Carson, Marianne; Coeverden, Els van; De Klein, Kirsten; Braks, Marieta; Krumeich, Anja

2017-01-01

In the Caribbean, mosquito-borne diseases are a public health threat. In Sint Eustatius, dengue, Chikungunya and Zika are now endemic. To control and prevent mosquito-borne diseases, the Sint Eustatius Public Health Department relies on the community to assist with the control of Aedes aegypti mosquito. Unfortunately, community based interventions are not always simple, as community perceptions and responses shape actions and influence behavioural responses Objective: The aim of this study was to determine how the Sint Eustatius population perceives the Aedes aegypti mosquito, mosquito-borne diseases and prevention and control measures and hypothesized that increased knowledge of the virus, vector, control and prevention should result in a lower AQ1 prevalence and incidence of mosquito-borne diseases. This study was conducted in Sint Eustatius island in the Eastern Caribbean. We combined qualitative and quantitative designs. We conducted interviews and focus groups discussions among community member and health professional in 2013 and 2015. We also conducted cross-sectional survey to assess local knowledge on the vector, virus, and control and prevention. The population is knowledgeable; ©however, mosquito-borne diseases are not the highest health priority. While local knowledge is sometimes put into action, it happens on the 20 household/individual level as opposed to the community level. After the 2014 CHIK outbreak, there was an increase in knowledge about mosquito control and mosquito-borne diseases. In the context of Sint Eustatius, when controlling the Aedes population it may be a strategic option to focus on the household level rather than the community and build collaborations with households by supporting them when they actively practice mosquito 25 control. To further increase the level of knowledge on the significance of mosquito-borne diseases, it may also be an option to contextualize the issue of the virus, vector, prevention and control into a

Northern range expansion of the Asian tiger mosquito (Aedes albopictus): Analysis of mosquito data from Connecticut, USA.

PubMed

Armstrong, Philip M; Andreadis, Theodore G; Shepard, John J; Thomas, Michael C

2017-05-01

The Asian tiger mosquito (Aedes albopictus) is an invasive species and important arbovirus vector that was introduced into the U.S. in the 1980's where it continues to expand its range. Winter temperature is an important constraint to its northward expansion, with potential range limits located between the 0° and -5°C mean cold month isotherm. Connecticut is located within this climatic zone and therefore, Ae. albopictus was monitored statewide to assess its northern range expansion and to delineate where populations can stably persist. Ae. albopictus females were monitored at fixed trapping sites throughout Connecticut from June-October over a 20-year period, 1997-2016. In addition, Ae. albopictus larvae and pupae were collected from tire habitats and tires were retrieved from the field in the spring and flooded to evaluate overwintering success of hatching larvae. Ae. albopictus was first detected during statewide surveillance when a single adult female was collected in 2006. This species was not collected again until 2010 and was subsequently detected each successive year with increasing abundance and distribution except following the unusually cold winters of 2014 and 2015. Ae. albopictus mosquitoes were most abundant in urban and suburban locations along the southwestern shoreline of Connecticut; however, single specimens were occasionally detected in central parts of the state. Field-collected females were also screened for arbovirus infection yielding two isolations of Cache Valley virus and one isolation of West Nile virus, highlighting the threat posed by this mosquito. Ae. albopictus overwintered in Connecticut under mild winter conditions as shown by recovery of hatched larvae from field collected tires in spring and by early season detection of larvae and pupae. This study documents the establishment and expansion of Ae. albopictus at the northern boundary of its range in the northeastern U.S. and provides a baseline for monitoring the future spread

Northern range expansion of the Asian tiger mosquito (Aedes albopictus): Analysis of mosquito data from Connecticut, USA

PubMed Central

Andreadis, Theodore G.; Shepard, John J.; Thomas, Michael C.

2017-01-01

Background The Asian tiger mosquito (Aedes albopictus) is an invasive species and important arbovirus vector that was introduced into the U.S. in the 1980's where it continues to expand its range. Winter temperature is an important constraint to its northward expansion, with potential range limits located between the 0° and -5°C mean cold month isotherm. Connecticut is located within this climatic zone and therefore, Ae. albopictus was monitored statewide to assess its northern range expansion and to delineate where populations can stably persist. Methodology/Principal findings Ae. albopictus females were monitored at fixed trapping sites throughout Connecticut from June-October over a 20-year period, 1997–2016. In addition, Ae. albopictus larvae and pupae were collected from tire habitats and tires were retrieved from the field in the spring and flooded to evaluate overwintering success of hatching larvae. Ae. albopictus was first detected during statewide surveillance when a single adult female was collected in 2006. This species was not collected again until 2010 and was subsequently detected each successive year with increasing abundance and distribution except following the unusually cold winters of 2014 and 2015. Ae. albopictus mosquitoes were most abundant in urban and suburban locations along the southwestern shoreline of Connecticut; however, single specimens were occasionally detected in central parts of the state. Field-collected females were also screened for arbovirus infection yielding two isolations of Cache Valley virus and one isolation of West Nile virus, highlighting the threat posed by this mosquito. Ae. albopictus overwintered in Connecticut under mild winter conditions as shown by recovery of hatched larvae from field collected tires in spring and by early season detection of larvae and pupae. Conclusions/Significance This study documents the establishment and expansion of Ae. albopictus at the northern boundary of its range in the

Identification of Wolbachia Strains in Mosquito Disease Vectors

PubMed Central

Osei-Poku, Jewelna; Han, Calvin; Mbogo, Charles M.; Jiggins, Francis M.

2012-01-01

Wolbachia bacteria are common endosymbionts of insects, and some strains are known to protect their hosts against RNA viruses and other parasites. This has led to the suggestion that releasing Wolbachia-infected mosquitoes could prevent the transmission of arboviruses and other human parasites. We have identified Wolbachia in Kenyan populations of the yellow fever vector Aedes bromeliae and its relative Aedes metallicus, and in Mansonia uniformis and Mansonia africana, which are vectors of lymphatic filariasis. These Wolbachia strains cluster together on the bacterial phylogeny, and belong to bacterial clades that have recombined with other unrelated strains. These new Wolbachia strains may be affecting disease transmission rates of infected mosquito species, and could be transferred into other mosquito vectors as part of control programs. PMID:23185484

Effect of Quorum Sensing by Staphylococcus epidermidis on the Attraction Response of Female Adult Yellow Fever Mosquitoes, Aedes aegypti aegypti (Linnaeus) (Diptera: Culicidae), to a Blood-Feeding Source

PubMed Central

Zhang, Xinyang; Crippen, Tawni L.; Coates, Craig J.; Wood, Thomas K.; Tomberlin, Jeffery K.

2015-01-01

Aedes aegypti, the principal vector of yellow fever and dengue fever, is responsible for more than 30,000 deaths annually. Compounds such as carbon dioxide, amino acids, fatty acids and other volatile organic compounds (VOCs) have been widely studied for their role in attracting Ae. aegypti to hosts. Many VOCs from humans are produced by associated skin microbiota. Staphyloccocus epidermidis, although not the most abundant bacteria according to surveys of relative 16S ribosomal RNA abundance, commonly occurs on human skin. Bacteria demonstrate population level decision-making through quorum sensing. Many quorum sensing molecules, such as indole, volatilize and become part of the host odor plum. To date, no one has directly demonstrated the link between quorum sensing (i.e., decision-making) by bacteria associated with a host as a factor regulating arthropod vector attraction. This study examined this specific question with regards to S. epidermidis and Ae. aegypti. Pairwise tests were conducted to examine the response of female Ae. aegypti to combinations of tryptic soy broth (TSB) and S. epidermidis wildtype and agr- strains. The agr gene expresses an accessory gene regulator for quorum sensing; therefore, removing this gene inhibits quorum sensing of the bacteria. Differential attractiveness of mosquitoes to the wildtype and agr- strains was observed. Both wildtype and the agr- strain of S. epidermidis with TSB were marginally more attractive to Ae. aegypti than the TSB alone. Most interestingly, the blood-feeder treated with wildtype S. epidermidis/TSB attracted 74% of Ae. aegypti compared to the agr- strain of S. epidermidis/TSB (P ≤ 0.0001). This study is the first to suggest a role for interkingdom communication between host symbiotic bacteria and mosquitoes. This may have implications for mosquito decision-making with regards to host detection, location and acceptance. We speculate that mosquitoes “eavesdrop” on the chemical discussions occurring

Adult repellency and larvicidal activity of five plant essential oils against mosquitoes.

PubMed

Zhu, Junwei; Zeng, Xiaopeng; Yanma; Liu, Ting; Qian, Kuen; Han, Yuhua; Xue, Suqin; Tucker, Brad; Schultz, Gretchen; Coats, Joel; Rowley, Wayne; Zhang, Aijun

2006-09-01

The larvicidal activity and repellency of 5 plant essential oils--thyme oil, catnip oil, amyris oil, eucalyptus oil, and cinnamon oil--were tested against 3 mosquito species: Aedes albopictus, Ae. aegypti, and Culex pipiens pallens. Larvicidal activity of these essentials oils was evaluated in the laboratory against 4th instars of each of the 3 mosquito species, and amyris oil demonstrated the greatest inhibitory effect with LC50 values in 24 h of 58 microg/ml (LC90 = 72 microg/ml) for Ae. aegypti, 78 microg/ml (LC90 = 130 microg/ml) for Ae. albopictus, and 77 microg/ml (LC90 = 123 microg/ml) for Cx. p. pallens. The topical repellency of these selected essential oils and deet against laboratory-reared female blood-starved Ae. albopictus was examined. Catnip oil seemed to be the most effective and provided 6-h protection at both concentrations tested (23 and 468 microg/ cm2). Thyme oil had the highest effectiveness in repelling this species, but the repellency duration was only 2 h. The applications using these natural product essential oils in mosquito control are discussed.

Insecticide resistance status of United States populations of Aedes albopictus and mechanisms involved

USDA-ARS?s Scientific Manuscript database

Aedes albopictus (Skuse) is an invasive mosquito that has become an important vector of chikungunya and dengue viruses. Immature Ae. albopictus thrive in backyard household containers that require treatment with larvicides and when adult populations reach pest levels or disease transmission is ongoi...

A malaria transmission-directed model of mosquito life cycle and ecology

PubMed Central

2011-01-01

Background Malaria is a major public health issue in much of the world, and the mosquito vectors which drive transmission are key targets for interventions. Mathematical models for planning malaria eradication benefit from detailed representations of local mosquito populations, their natural dynamics and their response to campaign pressures. Methods A new model is presented for mosquito population dynamics, effects of weather, and impacts of multiple simultaneous interventions. This model is then embedded in a large-scale individual-based simulation and results for local elimination of malaria are discussed. Mosquito population behaviours, such as anthropophily and indoor feeding, are included to study their effect upon the efficacy of vector control-based elimination campaigns. Results Results for vector control tools, such as bed nets, indoor spraying, larval control and space spraying, both alone and in combination, are displayed for a single-location simulation with vector species and seasonality characteristic of central Tanzania, varying baseline transmission intensity and vector bionomics. The sensitivities to habitat type, anthropophily, indoor feeding, and baseline transmission intensity are explored. Conclusions The ability to model a spectrum of local vector species with different ecologies and behaviours allows local customization of packages of interventions and exploration of the effect of proposed new tools. PMID:21999664

Regulation of Aedes aegypti Population Dynamics in Field Systems: Quantifying Direct and Delayed Density Dependence

PubMed Central

Walsh, Rachael K.; Aguilar, Cristobal L.; Facchinelli, Luca; Valerio, Laura; Ramsey, Janine M.; Scott, Thomas W.; Lloyd, Alun L.; Gould, Fred

2013-01-01

Transgenic strains of Aedes aegypti have been engineered to help control transmission of dengue virus. Although resources have been invested in developing the strains, we lack data on the ecology of mosquitoes that could impact the success of this approach. Although studies of intra-specific competition have been conducted using Ae. aegypti larvae, none of these studies examine mixed age cohorts at densities that occur in the field, with natural nutrient levels. Experiments were conducted in Mexico to determine the impact of direct and delayed density dependence on Ae. aegypti populations. Natural water, food, and larval densities were used to estimate the impacts of density dependence on larval survival, development, and adult body size. Direct and delayed density-dependent factors had a significant impact on larval survival, larval development, and adult body size. These results indicate that control methods attempting to reduce mosquito populations may be counteracted by density-dependent population regulation. PMID:23669230

Mosquito Life Cycle

EPA Pesticide Factsheets

Knowing the stages of the mosquito's life will help you prevent mosquitoes around your home and help you choose the right pesticides for your needs, if you decide to use them. All mosquito species go through four distinct stages during their live cycle.

Technologies to Combat Aedes Mosquitoes: A Model Based on Smart City.

PubMed

de Souza Silva, Geovanna Cristine; Peltonen, Laura-Maria; Pruinelli, Lisiane; Yoshikazu Shishido, Henrique; Jacklin Eler, Gabrielle

2018-01-01

Aedes aegypti and Aedes albopictus mosquitoes are responsible for the transmission of diseases such as dengue fever, yellow fever, chikungunya fever, zika virus fever, some of which can cause irreversible central nervous system problems and death. This study investigates what technologies are being used for combatting and monitoring the Aedes mosquitoes and to propose joining these technologies into a single and complete solution using the Smart Cities concept. A search for newscasts on Google and mobile apps in app stores were performed to identify technological solutions for combat to Aedes mosquitoes. Also, a model for joint technology was proposed. Results identified the following technologies: 170 software, two sensors, two drones, one electronic device, ten mosquito traps/lures, seven biological tools, six biotechnologies, and eight chemical formulations. Technological resources and adoption of preventive measures by the population could be a useful method for the mosquito control. Examples include a georeferenced model for identification and examination of larvae, application of chemical/biological products, real-time mapping, sending of educational materials via email or social media for the population, and alerts to health professionals in the zones of combat/risk. In combination, these technologies may indicate a better solution to the current problem.

Application Site and Mosquito Age Influences Malathion- and Permethrin-Induced Mortality in Culex quinquefasciatus (Diptera: Culicidae).

PubMed

Aldridge, Robert L; Kaufman, Phillip E; Bloomquist, Jeffrey R; Gezan, Salvador A; Linthicum, Kenneth J

2017-11-07

Concentrations of malathion and permethrin typical in droplets generated from ultra-low-volume and low-volume applications used to control mosquito populations were evaluated for efficacy against multiple-aged Culex quinquefasciatus Say (Diptera: Culicidae), using a topical bioassay. Although insecticide droplets will impinge on many exoskeletal body regions and a range of ages of mosquitoes in a population, traditional mosquito topical bioassays focus pesticide application to the mesothoracic pleural or dorsal regions across an average mosquito age (e.g., 3-7 d). Our results document nonuniform insecticide sensitivity across body regions at ages not previously assessed in mosquitoes (teneral and 14-d old). We expect our findings to influence the topical bioassay process, illustrating the difference in mosquito body regions and ages that ultimately may explain insecticide effectiveness wherever droplets impinge upon the mosquito body during field control applications. Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Variation in Aedes aegypti Mosquito Competence for Zika Virus Transmission.

PubMed

Roundy, Christopher M; Azar, Sasha R; Rossi, Shannan L; Huang, Jing H; Leal, Grace; Yun, Ruimei; Fernandez-Salas, Ildefonso; Vitek, Christopher J; Paploski, Igor A D; Kitron, Uriel; Ribeiro, Guilherme S; Hanley, Kathryn A; Weaver, Scott C; Vasilakis, Nikos

2017-04-01

To test whether Zika virus has adapted for more efficient transmission by Aedes aegypti mosquitoes, leading to recent urban outbreaks, we fed mosquitoes from Brazil, the Dominican Republic, and the United States artificial blood meals containing 1 of 3 Zika virus strains (Senegal, Cambodia, Mexico) and monitored infection, dissemination, and virus in saliva. Contrary to our hypothesis, Cambodia and Mexica strains were less infectious than the Senegal strain. Only mosquitoes from the Dominican Republic transmitted the Cambodia and Mexica strains. However, blood meals from viremic mice were more infectious than artificial blood meals of comparable doses; the Cambodia strain was not transmitted by mosquitoes from Brazil after artificial blood meals, whereas 61% transmission occurred after a murine blood meal (saliva titers up to 4 log 10 infectious units/collection). Although regional origins of vector populations and virus strain influence transmission efficiency, Ae. aegypti mosquitoes appear to be competent vectors of Zika virus in several regions of the Americas.

Variation in Aedes aegypti Mosquito Competence for Zika Virus Transmission

PubMed Central

Roundy, Christopher M.; Azar, Sasha R.; Rossi, Shannan L.; Huang, Jing H.; Leal, Grace; Yun, Ruimei; Fernandez-Salas, Ildefonso; Vitek, Christopher J.; Paploski, Igor A.D.; Kitron, Uriel; Ribeiro, Guilherme S.; Hanley, Kathryn A.

2017-01-01

To test whether Zika virus has adapted for more efficient transmission by Aedes aegypti mosquitoes, leading to recent urban outbreaks, we fed mosquitoes from Brazil, the Dominican Republic, and the United States artificial blood meals containing 1 of 3 Zika virus strains (Senegal, Cambodia, Mexico) and monitored infection, dissemination, and virus in saliva. Contrary to our hypothesis, Cambodia and Mexica strains were less infectious than the Senegal strain. Only mosquitoes from the Dominican Republic transmitted the Cambodia and Mexica strains. However, blood meals from viremic mice were more infectious than artificial blood meals of comparable doses; the Cambodia strain was not transmitted by mosquitoes from Brazil after artificial blood meals, whereas 61% transmission occurred after a murine blood meal (saliva titers up to 4 log10 infectious units/collection). Although regional origins of vector populations and virus strain influence transmission efficiency, Ae. aegypti mosquitoes appear to be competent vectors of Zika virus in several regions of the Americas. PMID:28287375

Evidence for regular ongoing introductions of mosquito disease vectors into the Galápagos Islands

PubMed Central

Bataille, Arnaud; Cunningham, Andrew A.; Cedeño, Virna; Cruz, Marilyn; Eastwood, Gillian; Fonseca, Dina M.; Causton, Charlotte E.; Azuero, Ronal; Loayza, Jose; Martinez, Jose D. Cruz; Goodman, Simon J.

2009-01-01

Wildlife on isolated oceanic islands is highly susceptible to the introduction of pathogens. The recent establishment in the Galápagos Islands of the mosquito Culex quinquefasciatus, a vector for diseases such as avian malaria and West Nile fever, is considered a serious risk factor for the archipelago's endemic fauna. Here we present evidence from the monitoring of aeroplanes and genetic analysis that C. quinquefasciatus is regularly introduced via aircraft into the Galápagos Archipelago. Genetic population structure and admixture analysis demonstrates that these mosquitoes breed with, and integrate successfully into, already-established populations of C. quinquefasciatus in the Galápagos, and that there is ongoing movement of mosquitoes between islands. Tourist cruise boats and inter-island boat services are the most likely mechanism for transporting Culex mosquitoes between islands. Such anthropogenic mosquito movements increase the risk of the introduction of mosquito-borne diseases novel to Galápagos and their subsequent widespread dissemination across the archipelago. Failure to implement and maintain measures to prevent the human-assisted transport of mosquitoes to and among the islands could have catastrophic consequences for the endemic wildlife of Galápagos. PMID:19675009

Novel flaviviruses from mosquitoes: Mosquito-specific evolutionary lineages within the phylogenetic group of mosquito-borne flaviviruses

PubMed Central

Huhtamo, Eili; Cook, Shelley; Moureau, Gregory; Uzcátegui, Nathalie Y.; Sironen, Tarja; Kuivanen, Suvi; Putkuri, Niina; Kurkela, Satu; Harbach, Ralph E.; Firth, Andrew E.; Vapalahti, Olli; Gould, Ernest A.; de Lamballerie, Xavier

2014-01-01

Novel flaviviruses that are genetically related to pathogenic mosquito-borne flaviviruses (MBFV) have been isolated from mosquitoes in various geographical locations, including Finland. We isolated and characterized another novel virus of this group from Finnish mosquitoes collected in 2007, designated as Ilomantsi virus (ILOV). Unlike the MBFV that infect both vertebrates and mosquitoes, the MBFV-related viruses appear to be specific to mosquitoes similar to the insect-specific flaviviruses (ISFs). In this overview of MBFV-related viruses we conclude that they differ from the ISFs genetically and antigenically. Phylogenetic analyses separated the MBFV-related viruses isolated in Africa, the Middle East and South America from those isolated in Europe and Asia. Serological cross-reactions of MBFV-related viruses with other flaviviruses and their potential for vector-borne transmission require further characterization. The divergent MBFV-related viruses are probably significantly under sampled to date and provide new information on the variety, properties and evolution of vector-borne flaviviruses. PMID:25108382

A mosquito hemolymph odorant-binding protein family member specifically binds juvenile hormone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Il Hwan; Pham, Van; Jablonka, Willy

Juvenile hormone (JH) is a key regulator of insect development and reproduction. In adult mosquitoes, it is essential for maturation of the ovary and normal male reproductive behavior, but how JH distribution and activity is regulated after secretion is unclear. Here, we report a new type of specific JH-binding protein, given the name mosquito juvenile hormone-binding protein (mJHBP), which circulates in the hemolymph of pupal and adult Aedes aegypti males and females. mJHBP is a member of the odorant-binding protein (OBP) family, and orthologs are present in the genomes of Aedes, Culex, and Anopheles mosquito species. Using isothermal titration calorimetry,more » we show that mJHBP specifically binds JH II and JH III but not eicosanoids or JH derivatives. mJHBP was crystallized in the presence of JH III and found to have a double OBP domain structure reminiscent of salivary “long” D7 proteins of mosquitoes. We observed that a single JH III molecule is contained in the N-terminal domain binding pocket that is closed in an apparent conformational change by a C-terminal domain-derived α-helix. The electron density for the ligand indicated a high occupancy of the natural 10R enantiomer of JH III. Of note, mJHBP is structurally unrelated to hemolymph JHBP from lepidopteran insects. A low level of expression of mJHBP in Ae. aegypti larvae suggests that it is primarily active during the adult stage where it could potentially influence the effects of JH on egg development, mating behavior, feeding, or other processes.« less

A mosquito hemolymph odorant-binding protein family member specifically binds juvenile hormone.

PubMed

Kim, Il Hwan; Pham, Van; Jablonka, Willy; Goodman, Walter G; Ribeiro, José M C; Andersen, John F

2017-09-15

Juvenile hormone (JH) is a key regulator of insect development and reproduction. In adult mosquitoes, it is essential for maturation of the ovary and normal male reproductive behavior, but how JH distribution and activity is regulated after secretion is unclear. Here, we report a new type of specific JH-binding protein, given the name mosquito juvenile hormone-binding protein (mJHBP), which circulates in the hemolymph of pupal and adult Aedes aegypti males and females. mJHBP is a member of the odorant-binding protein (OBP) family, and orthologs are present in the genomes of Aedes , Culex , and Anopheles mosquito species. Using isothermal titration calorimetry, we show that mJHBP specifically binds JH II and JH III but not eicosanoids or JH derivatives. mJHBP was crystallized in the presence of JH III and found to have a double OBP domain structure reminiscent of salivary "long" D7 proteins of mosquitoes. We observed that a single JH III molecule is contained in the N-terminal domain binding pocket that is closed in an apparent conformational change by a C-terminal domain-derived α-helix. The electron density for the ligand indicated a high occupancy of the natural 10 R enantiomer of JH III. Of note, mJHBP is structurally unrelated to hemolymph JHBP from lepidopteran insects. A low level of expression of mJHBP in Ae. aegypti larvae suggests that it is primarily active during the adult stage where it could potentially influence the effects of JH on egg development, mating behavior, feeding, or other processes.

Guidelines to site selection for population surveillance and mosquito control trials: a case study from Mauritius.

PubMed

Iyaloo, Diana P; Elahee, Khouaildi B; Bheecarry, Ambicadutt; Lees, Rosemary Susan

2014-04-01

Many novel approaches to controlling mosquito vectors through the release of sterile and mass reared males are being developed in the face of increasing insecticide resistance and other limitations of current methods. Before full scale release programmes can be undertaken there is a need for surveillance of the target population, and investigation of parameters such as dispersal and longevity of released, as compared to wild males through mark-release-recapture (MRR) and other experiments, before small scale pilot trials can be conducted. The nature of the sites used for this field work is crucial to ensure that a trial can feasibly collect sufficient and relevant information, given the available resources and practical limitations, and having secured the correct regulatory, community and ethical approvals and support. Mauritius is considering the inclusion of the sterile insect technique (SIT), for population reduction of Aedes albopictus, as a component of the Ministry of Health and Quality of Life's 'Operational Plan for Prevention and Control of Chikungunya and Dengue'. As part of an investigation into the feasibility of integrating the SIT into the Integrated Vector Management (IVM) scheme in Mauritius a pilot trial is planned. Two potential sites have been selected for this purpose, Pointe des Lascars and Panchvati, villages in the North East of the country, and population surveillance has commenced. This case study will here be used to explore the considerations which go into determining the most appropriate sites for mosquito field research. Although each situation is unique, and an ideal site may not be available, this discussion aims to help researchers to consider and balance the important factors and select field sites that will meet their needs. Copyright © 2013 International Atomic Energy Agency 2013. Published by Elsevier B.V. All rights reserved.

A Synergistic Transcriptional Regulation of Olfactory Genes Drives Blood-Feeding Associated Complex Behavioral Responses in the Mosquito Anopheles culicifacies.

PubMed

Das De, Tanwee; Thomas, Tina; Verma, Sonia; Singla, Deepak; Chauhan, Charu; Srivastava, Vartika; Sharma, Punita; Kumari, Seena; Tevatiya, Sanjay; Rani, Jyoti; Hasija, Yasha; Pandey, Kailash C; Dixit, Rajnikant

2018-01-01

Decoding the molecular basis of host seeking and blood feeding behavioral evolution/adaptation in the adult female mosquitoes may provide an opportunity to design new molecular strategy to disrupt human-mosquito interactions. Although there is a great progress in the field of mosquito olfaction and chemo-detection, little is known about the sex-specific evolution of the specialized olfactory system of adult female mosquitoes that enables them to drive and manage the complex blood-feeding associated behavioral responses. A comprehensive RNA-Seq analysis of prior and post blood meal olfactory system of An. culicifacies mosquito revealed a minor but unique change in the nature and regulation of key olfactory genes that may play a pivotal role in managing diverse behavioral responses. Based on age-dependent transcriptional profiling, we further demonstrated that adult female mosquito's chemosensory system gradually learned and matured to drive the host-seeking and blood feeding behavior at the age of 5-6 days. A time scale expression analysis of Odorant Binding Proteins (OBPs) unravels unique association with a late evening to midnight peak biting time. Blood meal-induced switching of unique sets of OBP genes and Odorant Receptors (Ors) expression coincides with the change in the innate physiological status of the mosquitoes. Blood meal follows up experiments further provide enough evidence that how a synergistic and concurrent action of OBPs-Ors may drive "prior and post blood meal" associated complex behavioral events. A dominant expression of two sensory appendages proteins (SAP-1 & SAP2) in the legs of An. culicifacies suggests that this mosquito species may draw an extra advantage of having more sensitive appendages than An. stephensi , an urban malarial vector in the Indian subcontinents. Finally, our molecular modeling analysis predicts crucial amino acid residues for future functional characterization of the sensory appendages proteins which may play a central

Vector Competence of New Zealand Mosquitoes for Selected Arboviruses

PubMed Central

Kramer, Laura D.; Chin, Pam; Cane, Rachel P.; Kauffman, Elizabeth B.; Mackereth, Graham

2011-01-01

New Zealand (NZ) historically has been free of arboviral activity with the exception of Whataroa virus (Togaviridae: Alphavirus), which is established in bird populations and is transmitted by local mosquitoes. This naive situation is threatened by global warming, invasive mosquitoes, and tourism. To determine the threat of selected medically important arboviruses to NZ, vector competence assays were conducted using field collected endemic and introduced mosquito species. Four alphaviruses (Togaviridae): Barmah Forest virus, Chikungunya virus, Ross River virus, and Sindbis virus, and five flaviviruses (Flaviviridae): Dengue virus 2, Japanese encephalitis virus, Murray Valley encephalitis virus, West Nile virus, and Yellow fever virus were evaluated. Results indicate some NZ mosquito species are highly competent vectors of selected arboviruses, particularly alphaviruses, and may pose a threat were one of these arboviruses introduced at a time when the vector was prevalent and the climatic conditions favorable for virus transmission. PMID:21734146

Towards a Hybrid Agent-based Model for Mosquito Borne Disease.

PubMed

Mniszewski, S M; Manore, C A; Bryan, C; Del Valle, S Y; Roberts, D

2014-07-01

Agent-based models (ABM) are used to simulate the spread of infectious disease through a population. Detailed human movement, demography, realistic business location networks, and in-host disease progression are available in existing ABMs, such as the Epidemic Simulation System (EpiSimS). These capabilities make possible the exploration of pharmaceutical and non-pharmaceutical mitigation strategies used to inform the public health community. There is a similar need for the spread of mosquito borne pathogens due to the re-emergence of diseases such as chikungunya and dengue fever. A network-patch model for mosquito dynamics has been coupled with EpiSimS. Mosquitoes are represented as a "patch" or "cloud" associated with a location. Each patch has an ordinary differential equation (ODE) mosquito dynamics model and mosquito related parameters relevant to the location characteristics. Activities at each location can have different levels of potential exposure to mosquitoes based on whether they are inside, outside, or somewhere in-between. As a proof of concept, the hybrid network-patch model is used to simulate the spread of chikungunya through Washington, DC. Results are shown for a base case, followed by varying the probability of transmission, mosquito count, and activity exposure. We use visualization to understand the pattern of disease spread.

Zika virus: The transboundary pathogen from mosquito and updates.

PubMed

Kong, Weili; Li, Hengtao; Zhu, Jian

2018-01-01

Zika virus (ZIKV) is a mosquito-borne flavivirus that was relatively obscure until outbreaks started in 2013. ZIKV is associated with neurological manifestations such as Guillan-Barrè Syndrome in adult and microcephaly in the newborn population. Although the majority of disease mechanisms of ZIKV is unclear, some information was updated with new scientific evidence. Currently, there are no approved drugs or vaccine that can be used for therapy during ZIKV infection. Based on the transmission mechanism of ZIKV, vector control and safe sex seem to be the most effective available preventive measures against ZIKV spread. This study summarized the current ZIKV epidemiology, the status of the existing pathogenic mechanism of ZIKV, the development of potential compounds and vaccines against ZIKV, and the control efforts against ZIKV. Copyright © 2017 Elsevier Ltd. All rights reserved.

Inhibition of Malaria Infection in Transgenic Anopheline Mosquitoes Lacking Salivary Gland Cells

PubMed Central

Kasashima, Katsumi; Sezutsu, Hideki; Matsuoka, Hiroyuki

2016-01-01

Malaria is an important global public health challenge, and is transmitted by anopheline mosquitoes during blood feeding. Mosquito vector control is one of the most effective methods to control malaria, and population replacement with genetically engineered mosquitoes to block its transmission is expected to become a new vector control strategy. The salivary glands are an effective target tissue for the expression of molecules that kill or inactivate malaria parasites. Moreover, salivary gland cells express a large number of molecules that facilitate blood feeding and parasite transmission to hosts. In the present study, we adapted a functional deficiency system in specific tissues by inducing cell death using the mouse Bcl-2-associated X protein (Bax) to the Asian malaria vector mosquito, Anopheles stephensi. We applied this technique to salivary gland cells, and produced a transgenic strain containing extremely low amounts of saliva. Although probing times for feeding on mice were longer in transgenic mosquitoes than in wild-type mosquitoes, transgenic mosquitoes still successfully ingested blood. Transgenic mosquitoes also exhibited a significant reduction in oocyst formation in the midgut in a rodent malaria model. These results indicate that mosquito saliva plays an important role in malaria infection in the midgut of anopheline mosquitoes. The dysfunction in the salivary glands enabled the inhibition of malaria transmission from hosts to mosquito midguts. Therefore, salivary components have potential in the development of new drugs or genetically engineered mosquitoes for malaria control. PMID:27598328

Research Contributing to Improvements in Controlling Florida's Mosquitoes and Mosquito-borne Diseases.

PubMed

Tabachnick, Walter J

2016-09-28

Research on mosquitoes and mosquito-borne diseases has contributed to improvements in providing effective, efficient, and environmentally proper mosquito control. Florida has benefitted from several research accomplishments that have increased the state's mosquito control capabilities. Research with Florida's mosquitoes has resulted in the development of ecologically sound management of mosquito impoundments on Florida's east coast. This strategy, called Rotational Impoundment Management (RIM), has improved the ability to target the delivery of pesticides and has helped to reduce non-target effects and environmental damage. Research has led to the development of an arbovirus surveillance system which includes sentinel chicken surveillance, real time use of environmental contributing factors like meteorology and hydrology to target mosquito control, as well as public health efforts to mitigate disease outbreaks to areas with risk of disease. These research driven improvements have provided substantial benefits to all of Florida. More research is needed to meet the future challenges to reduce emerging pathogens like Zika virus and the consequences of environmental changes like global climate change that are likely to influence the effects of mosquito-borne pathogens on human health and well-being.

Mosquito Biology and Mosquito-Borne Disease Awareness Among Island Communities In Malaysia.

PubMed

Shafie, Aziz; Roslan, Muhammad Aidil; Ngui, Romano; Lim, Yvonne Ai Lian; Sulaiman, Wan Yusoff Wan

2016-12-01

Mosquito-borne diseases have been increasing at an alarming rate over the past decades. In Malaysia, one finds several important mosquito-borne diseases such as Japanese encephalitis, dengue, malaria, and chikungunya. Mosquito surveillance and control programs are the most effective way of detecting and controlling mosquito-borne diseases, but these programs are less effective without an aware and well-informed general public. In 2014 we used a questionnaire to evaluate the extent of awareness of basic mosquito biology and mosquito-borne diseases in 6 villages, Kampung Masjid, Kampung Teluk Gedung, Kampung Teluk Dalam, Kampung Ujung Kelawai, Kampung Sungai Pinang Besar, and Kampung Sungai Pinang Kechil on Pangkor Island, Malaysia. A total of 1,012 individuals responded to the questionnaire, consisting of 790 Malay (78.1%), 164 Chinese (16.2%), and 58 Indian (5.7%). More than 60% (Malay = 73.7%, Chinese = 64.0%, Indian = 79.3%) of the respondents were familiar with basic mosquito biology and practiced personal protection against mosquito bites, and the association was statistically significant (P = 0.02). However, the majority of the respondents had limited knowledge on mosquito-borne diseases, and this varied significantly among the 3 ethnic groups (P = 0.0001). Our recommendations are to improve and intensify public health education outreach programs to the island residents and to encourage community participation in vector control programs.

Insecticide-Treated Nets Can Reduce Malaria Transmission by Mosquitoes Which Feed Outdoors

PubMed Central

Govella, Nicodem J.; Okumu, Fredros O.; Killeen, Gerry F.

2010-01-01

Insecticide treated nets (ITNs) represent a powerful means for controlling malaria in Africa because the mosquito vectors feed primarily indoors at night. The proportion of human exposure that occurs indoors, when people are asleep and can conveniently use ITNs, is therefore very high. Recent evidence suggests behavioral changes by malaria mosquito populations to avoid contact with ITNs by feeding outdoors in the early evening. We adapt an established mathematical model of mosquito behavior and malaria transmission to illustrate how ITNs can achieve communal suppression of malaria transmission exposure, even where mosquito evade them and personal protection is modest. We also review recent reports from Tanzania to show that conventional mosquito behavior measures can underestimate the potential of ITNs because they ignore the importance of human movements. PMID:20207866

Nest Mosquito Trap quantifies contact rates between nesting birds and mosquitoes.

PubMed

Caillouët, Kevin A; Riggan, Anna E; Rider, Mark; Bulluck, Lesley P

2012-06-01

Accurate estimates of host-vector contact rates are required for precise determination of arbovirus transmission intensity. We designed and tested a novel mosquito collection device, the Nest Mosquito Trap (NMT), to collect mosquitoes as they attempt to feed on unrestrained nesting birds in artificial nest boxes. In the laboratory, the NMT collected nearly one-third of the mosquitoes introduced to the nest boxes. We then used these laboratory data to estimate our capture efficiency of field-collected bird-seeking mosquitoes collected over 66 trap nights. We estimated that 7.5 mosquitoes per trap night attempted to feed on nesting birds in artificial nest boxes. Presence of the NMT did not have a negative effect on avian nest success when compared to occupied nest boxes that were not sampled with the trap. Future studies using the NMT may elucidate the role of nestlings in arbovirus transmission and further refine estimates of nesting bird and vector contact rates. © 2012 The Society for Vector Ecology.

Nest Mosquito Trap quantifies contact rates between nesting birds and mosquitoes

PubMed Central

Caillouët, Kevin A.; Riggan, Anna E.; Rider, Mark; Bulluck, Lesley P.

2012-01-01

Accurate estimates of host-vector contact rates are required for precise determination of arbovirus transmission intensity. We designed and tested a novel mosquito collection device, the Nest Mosquito Trap (NMT), to collect mosquitoes as they attempt to feed on unrestrained nesting birds in artificial nest boxes. In the laboratory, the NMT collected nearly one-third of the mosquitoes introduced to the nest boxes. We then used these laboratory data to estimate our capture efficiency of field-collected bird-seeking mosquitoes collected over 66 trap nights. We estimated that 7.5 mosquitoes per trap night attempted to feed on nesting birds in artificial nest boxes. Presence of the NMT did not have a negative effect on avian nest success when compared to occupied nest boxes that were not sampled with the trap. Future studies using the NMT may elucidate the role of nestlings in arbovirus transmission and further refine estimates of nesting bird and vector contact rates. PMID:22548555

Composition and Genetic Diversity of Mosquitoes (Diptera: Culicidae) on Islands and Mainland Shores of Kenya’s Lakes Victoria and Baringo

PubMed Central

Ajamma, Yvonne Ukamaka; Villinger, Jandouwe; Omondi, David; Salifu, Daisy; Onchuru, Thomas Ogao; Njoroge, Laban; Muigai, Anne W. T.; Masiga, Daniel K.

2016-01-01

The Lake Baringo and Lake Victoria regions of Kenya are associated with high seroprevalence of mosquito-transmitted arboviruses. However, molecular identification of potential mosquito vector species, including morphologically identified ones, remains scarce. To estimate the diversity, abundance, and distribution of mosquito vectors on the mainland shores and adjacent inhabited islands in these regions, we collected and morphologically identified adult and immature mosquitoes and obtained the corresponding sequence variation at cytochrome c oxidase 1 (COI) and internal transcribed spacer region 2 (ITS2) gene regions. A total of 63 species (including five subspecies) were collected from both study areas, 47 of which have previously been implicated as disease vectors. Fourteen species were found only on island sites, which are rarely included in mosquito diversity surveys. We collected more mosquitoes, yet with lower species composition, at Lake Baringo (40,229 mosquitoes, 32 species) than at Lake Victoria (22,393 mosquitoes, 54 species). Phylogenetic analysis of COI gene sequences revealed Culex perexiguus and Cx. tenagius that could not be distinguished morphologically. Most Culex species clustered into a heterogeneous clade with closely related sequences, while Culex pipiens clustered into two distinct COI and ITS2 clades. These data suggest limitations in current morphological identification keys. This is the first DNA barcode report of Kenyan mosquitoes. To improve mosquito species identification, morphological identifications should be supported by their molecular data, while diversity surveys should target both adults and immatures. The diversity of native mosquito disease vectors identified in this study impacts disease transmission risks to humans and livestock. PMID:27402888

Mosquito Bites

MedlinePlus

... humans. Other mosquito-borne infections include yellow fever, malaria and some types of brain infection (encephalitis). Symptoms ... carry certain diseases, such as West Nile virus, malaria, yellow fever and dengue fever. The mosquito obtains ...

Insecticidal activity of Leptodactylus knudseni and Phyllomedusa vaillantii crude skin secretions against the mosquitoes Anopheles darlingi and Aedes aegypti

PubMed Central

2014-01-01

Background Mosquitoes are important vectors of several diseases, including malaria and dengue, and control measures are mostly performed using chemical insecticides. Unfortunately, mosquito resistance to commonly applied insecticides is widespread. Therefore, a prospection for new molecules with insecticidal activity based on Amazon biodiversity using the anurans Leptodactylus knudseni and Phyllomedusa vaillantii was performed against the mosquito species Anopheles darlingi and Aedes aegypti. Methods The granular secretion from anuran skin was obtained by manual stimulation, and lethal concentrations (LCs) for larvicidal and adulticidal tests were calculated using concentrations from 1-100 ppm. The skin secretions from the anuran species tested caused significant mortality within the first 24 hours on adults and larvae, but differed within the mosquito species. Results The skin secretions from the anuran species tested caused significant mortality within the first 24 hours on adults and larvae, but differed within the mosquito species. The calculated LC50 of L. knudseni skin secretions against An. darlingi was 0.15 and 0.2 ppm for adults and larvae, respectively, but much higher for Ae. aegypti, i.e., 19 and 38 ppm, respectively. Interestingly, the calculated LCs50 of P. vaillantii against both mosquito species in adults were similar, 1.8 and 2.1 ppm, respectively, but the LC50 for An. darlingi larvae was much lower (0.4 ppm) than for Ae aegypti (2.1 ppm). Conclusions The present experiments indicate that skin secretions from L. knudseni and P. vaillantii contain bioactive molecules with potent insecticide activity. The isolation and characterization of skin secretions components will provide new insights for potential insecticidal molecules. PMID:25165469

Composition and Genetic Diversity of Mosquitoes (Diptera: Culicidae) on Islands and Mainland Shores of Kenya's Lakes Victoria and Baringo.

PubMed

Ajamma, Yvonne Ukamaka; Villinger, Jandouwe; Omondi, David; Salifu, Daisy; Onchuru, Thomas Ogao; Njoroge, Laban; Muigai, Anne W T; Masiga, Daniel K

2016-11-01

The Lake Baringo and Lake Victoria regions of Kenya are associated with high seroprevalence of mosquito-transmitted arboviruses. However, molecular identification of potential mosquito vector species, including morphologically identified ones, remains scarce. To estimate the diversity, abundance, and distribution of mosquito vectors on the mainland shores and adjacent inhabited islands in these regions, we collected and morphologically identified adult and immature mosquitoes and obtained the corresponding sequence variation at cytochrome c oxidase 1 (COI) and internal transcribed spacer region 2 (ITS2) gene regions. A total of 63 species (including five subspecies) were collected from both study areas, 47 of which have previously been implicated as disease vectors. Fourteen species were found only on island sites, which are rarely included in mosquito diversity surveys. We collected more mosquitoes, yet with lower species composition, at Lake Baringo (40,229 mosquitoes, 32 species) than at Lake Victoria (22,393 mosquitoes, 54 species). Phylogenetic analysis of COI gene sequences revealed Culex perexiguus and Cx tenagius that could not be distinguished morphologically. Most Culex species clustered into a heterogeneous clade with closely related sequences, while Culex pipiens clustered into two distinct COI and ITS2 clades. These data suggest limitations in current morphological identification keys. This is the first DNA barcode report of Kenyan mosquitoes. To improve mosquito species identification, morphological identifications should be supported by their molecular data, while diversity surveys should target both adults and immatures. The diversity of native mosquito disease vectors identified in this study impacts disease transmission risks to humans and livestock. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America.

Testing fungus impregnated cloths for the control of adult Aedes aegypti under natural conditions.

PubMed

Paula, Adriano R; Carolino, Aline T; Silva, Carlos P; Pereira, César R; Samuels, Richard I

2013-09-08

Entomopathogenic fungi could be useful tools for reducing populations of the dengue mosquito Aedes aegypti. Here the efficiency of fungus (Metarhizium anisopliae) impregnated cloths (with and without imidacloprid [IMI]) was evaluated against adult A. aegypti in simulated human dwellings. Behaviour of mosquitoes in the presence of black cloths was also investigated. When mosquitoes were released into the test rooms, the lowest survival rates (38%) were seen when five black cloths impregnated with conidia of ESALQ 818 + 10 ppm IMI were fixed under tables and chairs. This result was significantly lower than the survival rate recorded when cloths were impregnated with ESALQ 818 alone (44%) or ESALQ 818 + 0.1 ppm IMI (43%). Blood fed A. aegypti had lower landing frequencies on black cloths than sucrose fed insects during the first 24 h following feeding, which may have been due to reduced flight activity. Few mosquitoes (4-5%) were observed to land on the cloths during the hours of darkness. The landing pattern of sucrose-fed mosquitoes on non-treated and fungus-treated cloths was similar. The synergism between M. anisopliae and IMI significantly reduced Aedes survival in simulated field conditions. The use of fungus impregnated cloths is a promising point source application method for the control of adult A. aegypti.

Novel flaviviruses from mosquitoes: mosquito-specific evolutionary lineages within the phylogenetic group of mosquito-borne flaviviruses.

PubMed

Huhtamo, Eili; Cook, Shelley; Moureau, Gregory; Uzcátegui, Nathalie Y; Sironen, Tarja; Kuivanen, Suvi; Putkuri, Niina; Kurkela, Satu; Harbach, Ralph E; Firth, Andrew E; Vapalahti, Olli; Gould, Ernest A; de Lamballerie, Xavier

2014-09-01

Novel flaviviruses that are genetically related to pathogenic mosquito-borne flaviviruses (MBFV) have been isolated from mosquitoes in various geographical locations, including Finland. We isolated and characterized another novel virus of this group from Finnish mosquitoes collected in 2007, designated as Ilomantsi virus (ILOV). Unlike the MBFV that infect both vertebrates and mosquitoes, the MBFV-related viruses appear to be specific to mosquitoes similar to the insect-specific flaviviruses (ISFs). In this overview of MBFV-related viruses we conclude that they differ from the ISFs genetically and antigenically. Phylogenetic analyses separated the MBFV-related viruses isolated in Africa, the Middle East and South America from those isolated in Europe and Asia. Serological cross-reactions of MBFV-related viruses with other flaviviruses and their potential for vector-borne transmission require further characterization. The divergent MBFV-related viruses are probably significantly under sampled to date and provide new information on the variety, properties and evolution of vector-borne flaviviruses. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Population Dynamics of Aedes aegypti and Dengue as Influenced by Weather and Human Behavior in San Juan, Puerto Rico

PubMed Central

Barrera, Roberto; Amador, Manuel; MacKay, Andrew J.

2011-01-01

Previous studies on the influence of weather on Aedes aegypti dynamics in Puerto Rico suggested that rainfall was a significant driver of immature mosquito populations and dengue incidence, but mostly in the drier areas of the island. We conducted a longitudinal study of Ae. aegypti in two neighborhoods of the metropolitan area of San Juan city, Puerto Rico where rainfall is more uniformly distributed throughout the year. We assessed the impacts of rainfall, temperature, and human activities on the temporal dynamics of adult Ae. aegypti and oviposition. Changes in adult mosquitoes were monitored with BG-Sentinel traps and oviposition activity with CDC enhanced ovitraps. Pupal surveys were conducted during the drier and wetter parts of the year in both neighborhoods to determine the contribution of humans and rains to mosquito production. Mosquito dynamics in each neighborhood was compared with dengue incidence in their respective municipalities during the study. Our results showed that: 1. Most pupae were produced in containers managed by people, which explains the prevalence of adult mosquitoes at times when rainfall was scant; 2. Water meters were documented for the first time as productive habitats for Ae. aegypti; 3. Even though Puerto Rico has a reliable supply of tap water and an active tire recycling program, water storage containers and discarded tires were important mosquito producers; 4. Peaks in mosquito density preceded maximum dengue incidence; and 5. Ae. aegypti dynamics were driven by weather and human activity and oviposition was significantly correlated with dengue incidence. PMID:22206021

Mosquito repellents for malaria prevention

PubMed Central

Maia, Marta F; Kliner, Merav; Richardson, Marty; Lengeler, Christian; Moore, Sarah J

2018-01-01

-treated clothing, and two trials investigated spatial repellents. Topical repellents Six RCTS, five of them cluster-randomized, investigated topical repellents involving residents of malaria-endemic regions. Four trials used topical repellents in combination with nets, but two trials undertaken in displaced populations used topical repellents alone. It is unclear if topical repellents can prevent clinical malaria (RR 0.65, 95% CI 0.4 to 1.07, very low certainty evidence) or malaria infection (RR 0.84, 95% CI 0.64 to 1.12, low-certainty evidence) caused by P. falciparum. It is also unclear if there is any protection against clinical cases of P. vivax (RR 1.32, 95% CI 0.99 to 1.76, low-certainty evidence) or incidence of infections (RR 1.07, 95% CI 0.80 to 1.41, low-certainty evidence). Subgroup analysis of trials including insecticide-treated nets did not show a protective effect of topical repellents against malaria. Only two studies did not include insecticide-treated nets, and they measured different outcomes; one reported a protective effect against clinical cases of P. falciparum (RR 0.40, 95% CI 0.23 to 0.71); but the other study measured no protective effect against malaria infection incidence caused by either P. falciparum or P. vivax. Insecticide-treated clothing Insecticide-treated clothing were investigated in trials conducted in refugee camps in Pakistan and amongst military based in the Colombian Amazon. Neither study provided participants with insecticide-treated nets. In the absence of nets, treated clothing may reduce the incidence of clinical malaria caused by P. falciparum by approximately 50% (RR 0.49, 95% CI 0.29 to 0.83, low-certainty evidence) and P. vivax (RR 0.64, 95% CI 0.40 to 1.01, low-certainty evidence). Spatial repellents Two cluster-randomized RCTs investigated mosquito coils for malaria prevention. We do not know the effect of spatial repellents on malaria prevention (RR 0.24, 95% CI 0.03 to 1.72, very low certainty evidence). There was large

UV light and urban pollution: bad cocktail for mosquitoes?

PubMed

Tetreau, Guillaume; Chandor-Proust, Alexia; Faucon, Frédéric; Stalinski, Renaud; Akhouayri, Idir; Prud'homme, Sophie M; Régent-Kloeckner, Myriam; Raveton, Muriel; Reynaud, Stéphane

2014-01-01

Mosquito breeding sites consist of water pools, which can either be large open areas or highly covered ponds with vegetation, thus with different light exposures combined with the presence in water of xenobiotics including polycyclic aromatic hydrocarbons (PAHs) generated by urban pollution. UV light and PAHs are abiotic factors known to both affect the mosquito insecticide resistance status. Nonetheless, their potential combined effects on the mosquito physiology have never been investigated. The present article aims at describing the effects of UV exposure alongside water contamination with two major PAH pollutants (fluoranthene and benzo[a]pyrene) on a laboratory population of the yellow fever mosquito Aedes aegypti. To evaluate the effects of PAH exposure and low energetic UV (UV-A) irradiation on mosquitoes, different parameters were measured including: (1) The PAH localization and its impact on cell mortality by fluorescent microscopy; (2) The detoxification capacities (cytochrome P450, glutathione-S-transferase, esterase); (3) The responses to oxidative stress (Reactive Oxygen Species-ROS) and (4) The tolerance of mosquito larvae to a bioinsecticide (Bacillus thuringiensis subsp. israelensis-Bti) and to five chemical insecticides (DDT, imidacloprid, permethrin, propoxur and temephos). Contrasting effects regarding mosquito cell mortality, detoxification and oxidative stress were observed as being dependent on the pollutant considered, despite the fact that the two PAHs belong to the same family. Moreover, UV is able to modify pollutant effects on mosquitoes, including tolerance to three insecticides (imidacloprid, propoxur and temephos), cell damage and response to oxidative stress. Taken together, our results suggest that UV and pollution, individually or in combination, are abiotic parameters that can affect the physiology and insecticide tolerance of mosquitoes; but the complexity of their direct effect and of their interaction will require further

Countering a bioterrorist introduction of pathogen-infected mosquitoes through mosquito control.

PubMed

Tabachnick, Walter J; Harvey, William R; Becnel, James J; Clark, Gary G; Connelly, C Roxanne; Day, Jonathan F; Linser, Paul J; Linthicum, Kenneth J

2011-06-01

The release of infected mosquitoes or other arthropods by bioterrorists, i.e., arboterrorism, to cause disease and terror is a threat to the USA. A workshop to assess mosquito control response capabilities to mount rapid and effective responses to eliminate an arboterrorism attack provided recommendations to improve capabilities in the USA. It is essential that mosquito control professionals receive training in possible responses, and it is recommended that a Council for Emergency Mosquito Control be established in each state to coordinate training, state resources, and actions for use throughout the state.

Heterogeneity of Mosquito (Diptera: Culicidae) Control Community Size, Research Productivity, and Arboviral Diseases Across the United States.

PubMed

Hamer, Gabriel L

2016-05-01

Multiple factors lead to extensive variation in mosquito and mosquito-borne virus control programs throughout the United States. This variation is related to differences in budgets, number of personnel, operational activities targeting nuisance or vector species, integration of Geographical Information Systems, and the degree of research and development to improve management interventions through collaboration with academic institutions. To highlight this heterogeneity, the current study evaluates associations among the size of a mosquito control community, the research productivity, and the mosquito-borne virus human disease burden among states within the continental United States. I used the attendance at state mosquito and vector control meetings as a proxy for the size of the mosquito control community in each state. To judge research productivity, I used all peer-reviewed publications on mosquitoes and mosquito-borne viruses using data originating in each state over a 5- and 20-yr period. Total neuroinvasive human disease cases caused by mosquito-borne viruses were aggregated for each state. These data were compared directly and after adjusting for differences in human population size for each state. Results revealed that mean meeting attendance was positively correlated with the number of publications in each state, but not after correcting for the size of the population in each state. Additionally, human disease cases were positively correlated with the number of publications in each state. Finally, mean meeting attendance and human disease cases were only marginally positively associated, and no correlation existed after correcting for human population size. These analyses indicated that the mosquito control community size, research productivity, and mosquito-borne viral human disease burden varied greatly among states. The mechanisms resulting in this variation were discussed and the consequences of this variation are important given the constantly

Larval ecology of mosquitoes in sylvatic arbovirus foci in southeastern Senegal

PubMed Central

2012-01-01

Background Although adult mosquito vectors of sylvatic arbovirus [yellow fever (YFV), dengue-2 (DENV-2) and chikungunya (CHIKV)] have been studied for the past 40 years in southeastern Senegal, data are still lacking on the ecology of larval mosquitoes in this area. In this study, we investigated the larval habitats of mosquitoes and characterized their seasonal and spatial dynamics in arbovirus foci. Methods We searched for wet microhabitats, classified in 9 categories, in five land cover classes (agriculture, forest, savannah, barren and village) from June, 2010 to January, 2011. Mosquito immatures were sampled monthly in up to 30 microhabitats of each category per land cover and bred until adult stage for determination. Results No wet microhabitats were found in the agricultural sites; in the remaining land covers immature stages of 35 mosquito species in 7 genera were sampled from 9 microhabitats (tree holes, fresh fruit husks, decaying fruit husks, puddles, bamboo holes, discarded containers, tires, rock holes and storage containers). The most abundant species was Aedes aegypti formosus, representing 30.2% of the collections, followed by 12 species, representing each more than 1% of the total, among them the arbovirus vectors Ae. vittatus (7.9%), Ae. luteocephalus (5.7%), Ae. taylori (5.0%), and Ae. furcifer (1.3%). Aedes aegypti, Cx. nebulosus, Cx. perfuscus, Cx. tritaeniorhynchus, Er. chrysogster and Ae. vittatus were the only common species collected from all land covers. Aedes furcifer and Ae. taylori were collected in fresh fruit husks and tree holes. Species richness and dominance varied significantly in land covers and microhabitats. Positive associations were found mainly between Ae. furcifer, Ae. taylori and Ae. luteocephalus. A high proportion of potential enzootic vectors that are not anthropophilic were found in the larval mosquito fauna. Conclusions In southeastern Senegal, Ae. furcifer and Ae. taylori larvae showed a more limited distribution

The mosquitoes (Diptera: Culidae) of Seychelles: taxonomy, ecology, vectorial importance, and identification keys.

PubMed

Le Goff, Gilbert; Boussès, Philippe; Julienne, Simon; Brengues, Cécile; Rahola, Nil; Rocamora, Gérard; Robert, Vincent

2012-09-21

During recent periods, the islands of the Republic of Seychelles experienced many diseases such as dengue, chikungunya, Bancroft's filaria and malaria. Mosquitoes transmit the agents that cause these diseases. Published information on mosquitoes in the Seychelles is notably dispersed in the literature. The maximum number of species obtained on a single field survey does not exceed 14 species. We performed a comprehensive bibliographic review using mosquito and Seychelles as the key words, as well as conducted a mosquito field survey for larval and adult stages during the rainy season in December 2008. Sixteen sites were sampled on four granitic islands (Mahé, Praslin, La Digue and Aride) and six sites on coralline atolls in the extreme southwest of the country (Aldabra group). We found published references to 21 mosquito species identified at least on one occasion in the Seychelles. Our collections comprised 18 species of mosquitoes, all of them from the subfamily Culicinae; no Anophelinae was found. We also confirm that Aedes seychellensis is a junior synonym of Ae. (Aedimorphus) albocephalus. The first records for Culex antennatus and Cx. sunyaniensis are presented from the country, specifically from Aldabra and Praslin, respectively. Based on a comparison of the taxa occurring on the granitic versus coralline islands, only three species, Ae. albocephalus, Cx. scottii and Cx. simpsoni are shared. Aedes albopictus appeared to exclude largely Ae. aegypti on the granitic islands; however, Ae. aegypti was common on Aldabra, where Ae. albopictus has not been recorded. The notable aggressiveness of mosquitoes towards humans on coralline islands was mainly due to two species, the females of which are difficult to distinguish: Ae. fryeri and Ae. (Aedimorphus) sp. A. The number of mosquito species collected at least once in the Seychelles is now 22, among which five species (Ae. (Adm) sp. A, Cx. stellatus, Uranotaenia browni. Ur. nepenthes and Ur. pandani) and one

The mosquitoes (Diptera: Culidae) of Seychelles: taxonomy, ecology, vectorial importance, and identification keys

PubMed Central

2012-01-01

Background During recent periods, the islands of the Republic of Seychelles experienced many diseases such as dengue, chikungunya, Bancroft’s filaria and malaria. Mosquitoes transmit the agents that cause these diseases. Published information on mosquitoes in the Seychelles is notably dispersed in the literature. The maximum number of species obtained on a single field survey does not exceed 14 species. Methods We performed a comprehensive bibliographic review using mosquito and Seychelles as the key words, as well as conducted a mosquito field survey for larval and adult stages during the rainy season in December 2008. Sixteen sites were sampled on four granitic islands (Mahé, Praslin, La Digue and Aride) and six sites on coralline atolls in the extreme southwest of the country (Aldabra group). Results We found published references to 21 mosquito species identified at least on one occasion in the Seychelles. Our collections comprised 18 species of mosquitoes, all of them from the subfamily Culicinae; no Anophelinae was found. We also confirm that Aedes seychellensis is a junior synonym of Ae. (Aedimorphus) albocephalus. The first records for Culex antennatus and Cx. sunyaniensis are presented from the country, specifically from Aldabra and Praslin, respectively. Based on a comparison of the taxa occurring on the granitic versus coralline islands, only three species, Ae. albocephalus, Cx. scottii and Cx. simpsoni are shared. Aedes albopictus appeared to exclude largely Ae. aegypti on the granitic islands; however, Ae. aegypti was common on Aldabra, where Ae. albopictus has not been recorded. The notable aggressiveness of mosquitoes towards humans on coralline islands was mainly due to two species, the females of which are difficult to distinguish: Ae. fryeri and Ae. (Aedimorphus) sp. A. The number of mosquito species collected at least once in the Seychelles is now 22, among which five species (Ae. (Adm) sp. A, Cx. stellatus, Uranotaenia browni. Ur. nepenthes

Malaria infection in mosquitoes decreases the personal protection offered by permethrin-treated bednets.

PubMed

Thiévent, Kevin; Hofer, Lorenz; Rapp, Elise; Tambwe, Mgeni Mohamed; Moore, Sarah; Koella, Jacob C

2018-05-04

Insecticides targeting adult mosquitoes are the main way of controlling malaria. They work not only by killing mosquitoes, but also by repelling and irritating them. Indeed their repellent action gives valuable personal protection against biting mosquitoes. In the context of malaria control this personal protection is especially relevant when mosquitoes are infectious, whereas to protect the community we would prefer that the mosquitoes that are not yet infectious are killed (so, not repelled) by the insecticide. As the infectious stage of malaria parasites increases the motivation of mosquitoes to bite, we predicted that it would also change their behavioural response to insecticides. With two systems, a laboratory isolate of the rodent malaria Plasmodium berghei infecting Anopheles gambiae and several isolates of P. falciparum obtained from schoolchildren in Tanzania that infected Anopheles arabiensis, we found that mosquitoes harbouring the infectious stage (the sporozoites) of the parasite were less repelled by permethrin-treated nets than uninfected ones. Our results suggest that, at least in the laboratory, malaria infection decreases the personal protection offered by insecticide-treated nets at the stage where the personal protection is most valuable. Further studies must investigate whether these results hold true in the field and whether the less effective personal protection can be balanced by increased community protection.

Evaluation of various models of propane-powered mosquito traps.

PubMed

Kline, Daniel L

2002-06-01

Large cage and field studies were conducted to determine the efficacy of various models of propane-powered mosquito traps. These traps utilized counterflow technology in conjunction with catalytic combustion to produce attractants (carbon dioxide, water vapor, and heat) and a thermoelectric generator that converted excess heat into electricity for stand-alone operation. The cage studies showed that large numbers of Aedes aegypti and Ochlerotatus taeniorhynchus were captured and that each progressive model resulted in increased trapping efficiency. In several field studies against natural populations of mosquitoes two different propane traps were compared against two other trap systems, the professional (PRO) and counterflow geometry (CFG) traps. In these studies the propane traps consistently caught more mosquitoes than the PRO trap and significantly fewer mosquitoes than the CFG traps. The difference in collection size between the CFG and propane traps was due mostly to Anopheles crucians. In spring 1997 the CFG trap captured 3.6X more An. crucians than the Portable Propane (PP) model and in spring 1998 it captured 6.3X more An. crucians than the Mosquito Magnet Beta-1 (MMB-1) trap. Both the PP and MMB-1 captured slightly more Culex spp. than the CFG trap.

Insecticide resistance, associated mechanisms and fitness aspects in two Brazilian Stegomyia aegypti (= Aedes aegypti) populations.

PubMed

Viana-Medeiros, P F; Bellinato, D F; Martins, A J; Valle, D

2017-12-01

In Brazil, insecticide resistance in Stegomyia aegypti (= Aedes aegypti) (Diptera: Culicidae) populations to pyrethroids and to the organophosphate (OP) temephos is disseminated. Currently, insect growth regulators (IGRs) and the OP malathion are employed against larvae and adults, respectively. Bioassays with mosquitoes from two northeast municipalities, Crato and Aracaju, revealed, in both populations, susceptibility to IGRs and malathion (RR 95  ≤ 2.0), confirming the effectiveness of these compounds. By contrast, temephos and deltamethrin (pyrethroid) resistance levels were high (RR 95  > 10), which is consistent with the use of intense chemical control. In Crato, RR 95 values were > 50 for both compounds. Knock-down-resistant (kdr) mutants in the voltage-gated sodium channel, the pyrethroid target site, were found in 43 and 32%, respectively, of Aracaju and Crato mosquitoes. Biochemical assays revealed higher metabolic resistance activity (esterases, mixed function oxidases and glutathione-S-transferases) at Aracaju. With respect to fitness aspects, mating effectiveness was equivalently impaired in both populations, but Aracaju mosquitoes showed more damaging effects in terms of longer larval development, decreased bloodmeal acceptance, reduced engorgement and lower numbers of eggs laid per female. Compared with mosquitoes in Crato, Aracaju mosquitoes exhibited lower OP and pyrethroid RR 95 , increased activity of detoxifying enzymes and greater effect on fitness. The potential relationship between insecticide resistance mechanisms and mosquito viability is discussed. © 2017 The Authors. Medical and Veterinary Entomology published by John Wiley & Sons Ltd on behalf of The Royal Entomological Society.

More than one rabbit out of the hat: Radiation, transgenic and symbiont-based approaches for sustainable management of mosquito and tsetse fly populations.

PubMed

Bourtzis, Kostas; Lees, Rosemary Susan; Hendrichs, Jorge; Vreysen, Marc J B

2016-05-01

Mosquitoes (Diptera: Culicidae) and tsetse flies (Diptera: Glossinidae) are bloodsucking vectors of human and animal pathogens. Mosquito-borne diseases (malaria, filariasis, dengue, zika, and chikungunya) cause severe mortality and morbidity annually, and tsetse fly-borne diseases (African trypanosomes causing sleeping sickness in humans and nagana in livestock) cost Sub-Saharan Africa an estimated US$ 4750 million annually. Current reliance on insecticides for vector control is unsustainable: due to increasing insecticide resistance and growing concerns about health and environmental impacts of chemical control there is a growing need for novel, effective and safe biologically-based methods that are more sustainable. The integration of the sterile insect technique has proven successful to manage crop pests and disease vectors, particularly tsetse flies, and is likely to prove effective against mosquito vectors, particularly once sex-separation methods are improved. Transgenic and symbiont-based approaches are in development, and more advanced in (particularly Aedes) mosquitoes than in tsetse flies; however, issues around stability, sustainability and biosecurity have to be addressed, especially when considering population replacement approaches. Regulatory issues and those relating to intellectual property and economic cost of application must also be overcome. Standardised methods to assess insect quality are required to compare and predict efficacy of the different approaches. Different combinations of these three approaches could be integrated to maximise their benefits, and all have the potential to be used in tsetse and mosquito area-wide integrated pest management programmes. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Functional characterization of the octenol receptor neuron on the maxillary palps of the yellow fever mosquito, Aedes aegypti

USDA-ARS?s Scientific Manuscript database

1-Octen-3-ol (octenol) is a common attractant released by vertebrates which in combination with carbon dioxide attracts haematophagous arthropods including mosquitoes. A receptor neuron contained within basiconic sensilla on the maxillary palps of adult mosquitoes responds selectively to 1-octen-3-o...

Perceived nuisance of mosquitoes on the Isle of Sheppey, Kent, UK.

PubMed

Hutchinson, Robert A; Lindsay, Steve W

2006-09-01

Little is known about the biting nuisance of mosquitoes in the UK, despite the high numbers found in some locations. A telephone questionnaire survey was used to determine the perceived nuisance of biting insects on the Isle of Sheppey, Kent, a place notorious for mosquitoes. Two hundred randomly selected individuals were interviewed and asked if they suffered from mosquito bites. If they answered yes, they were asked to describe where and when they were bitten, and what measures they took against mosquitoes. Forty-six percent of respondents completed the questionnaire. Of those, 50% reported being bitten by mosquitoes, mostly outside during the summer. Seventy percent said that most biting occurred during the evening and night. Of those respondents who protected themselves against biting (27), most used repellents (70%), with the remainder changing their behaviour to avoid mosquitoes, including closing or screening windows (33%), wearing thicker clothes (7%) and spraying insecticide (4%). One person slept under a bednet in summer (4%). This study provides evidence that on the Isle of Sheppey mosquitoes are considered a major nuisance by a sizeable proportion of the population. Since there is growing interest in the threat posed by new and emerging diseases in the UK, health authorities will need to make substantial efforts to inform and reassure the public about the threats posed by mosquitoes in areas where they are common.

Effects of Irrigation and Rainfall on the Population Dynamics of Rift Valley Fever and Other Arbovirus Mosquito Vectors in the Epidemic-Prone Tana River County, Kenya.

PubMed

Sang, R; Lutomiah, J; Said, M; Makio, A; Koka, H; Koskei, E; Nyunja, A; Owaka, S; Matoke-Muhia, D; Bukachi, S; Lindahl, J; Grace, D; Bett, B

2017-03-01

Rift Valley fever (RVF) is a mosquito-borne viral zoonosis that is found in most regions of sub-Saharan Africa, and it affects humans, livestock, and some wild ungulates. Outbreaks are precipitated by an abundance of mosquito vectors associated with heavy persistent rainfall with flooding. We determined the impact of flood-irrigation farming and the effect of environmental parameters on the ecology and densities of primary and secondary vectors of the RVF virus (RVFV) in an RVF-epidemic hotspot in the Tana River Basin, Kenya. Mosquito sampling was conducted in farms and villages (settlements) in an irrigated and a neighboring nonirrigated site (Murukani). Overall, a significantly higher number of mosquitoes were collected in farms in the irrigation scheme compared with villages in the same area (P < 0.001), or farms (P < 0.001), and villages (P = 0.03) in Murukani. In particular, key primary vectors of RVFV, Aedes mcintoshi Marks and Aedes ochraceous Theobald, were more prevalent in the farms compared with villages in the irrigation scheme (P = 0.001) both during the dry and the wet seasons. Similarly, there was a greater abundance of secondary vectors, particularly Culex univittatus Theobald and Culex pipiens (L.) in the irrigation scheme than in the Murukani area. Rainfall and humidity were positively correlated with mosquito densities, particularly the primary vectors. Adult floodwater mosquitoes and Mansonia spp. were collected indoors; immatures of Ae. mcintoshi and secondary vectors were collected in the irrigation drainage canals, whereas those of Ae. ochraceous and Aedes sudanensis Theobald were missing from these water bodies. In conclusion, irrigation in RVF endemic areas provides conducive resting and breeding conditions for vectors of RVFV and other endemic arboviruses. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America.

Response of adult mosquitoes to light emitting diodes placed in resting boxes and in the field.

USDA-ARS?s Scientific Manuscript database

Resting boxes are passive devices used to attract and capture mosquitoes seeking shelter. Increasing the attractiveness of these devices could improve their effectiveness. Light emitting diodes (LEDs) can be attractive to mosquitoes when used together with other trapping devices. Therefore restin...

Research Contributing to Improvements in Controlling Florida’s Mosquitoes and Mosquito-Borne Diseases

PubMed Central

Tabachnick, Walter J.

2016-01-01

Research on mosquitoes and mosquito-borne diseases has contributed to improvements in providing effective, efficient, and environmentally proper mosquito control. Florida has benefitted from several research accomplishments that have increased the state’s mosquito control capabilities. Research with Florida’s mosquitoes has resulted in the development of ecologically sound management of mosquito impoundments on Florida’s east coast. This strategy, called Rotational Impoundment Management (RIM), has improved the ability to target the delivery of pesticides and has helped to reduce non-target effects and environmental damage. Research has led to the development of an arbovirus surveillance system which includes sentinel chicken surveillance, real time use of environmental contributing factors like meteorology and hydrology to target mosquito control, as well as public health efforts to mitigate disease outbreaks to areas with risk of disease. These research driven improvements have provided substantial benefits to all of Florida. More research is needed to meet the future challenges to reduce emerging pathogens like Zika virus and the consequences of environmental changes like global climate change that are likely to influence the effects of mosquito-borne pathogens on human health and well-being. PMID:27690112

FTA Cards Facilitate Storage, Shipment, and Detection of Arboviruses in Infected Aedes aegypti Collected in Adult Mosquito Traps.

PubMed

Hall-Mendelin, Sonja; Hewitson, Glen R; Genge, Doris; Burtonclay, Peter J; De Jong, Amanda J; Pyke, Alyssa T; van den Hurk, Andrew F

2017-05-01

AbstractThe utility of applying infected Aedes aegypti to Flinders Technology Associates (FTA ® ) cards for storage, transport, and detection of dengue, Zika, and Barmah Forest viruses was assessed in laboratory-based experiments. The mosquitoes had been removed from Gravid Aedes Traps maintained under conditions of high temperature and humidity. RNA of all viruses could be detected in infected mosquitoes on FTA cards either individually or in pools with uninfected mosquitoes, and stored for up to 28 days. Importantly, there was only a minimal decrease in RNA levels in mosquitoes between days 0 and 28, indicating that viral RNA was relatively stable on the cards. FTA cards thus provide a mechanism for storing potentially infected mosquitoes collected in the field and transporting them to a central diagnostic facility for virus detection.

FTA Cards Facilitate Storage, Shipment, and Detection of Arboviruses in Infected Aedes aegypti Collected in Adult Mosquito Traps

PubMed Central

Hall-Mendelin, Sonja; Hewitson, Glen R.; Genge, Doris; Burtonclay, Peter J.; De Jong, Amanda J.; Pyke, Alyssa T.; van den Hurk, Andrew F.

2017-01-01

The utility of applying infected Aedes aegypti to Flinders Technology Associates (FTA®) cards for storage, transport, and detection of dengue, Zika, and Barmah Forest viruses was assessed in laboratory-based experiments. The mosquitoes had been removed from Gravid Aedes Traps maintained under conditions of high temperature and humidity. RNA of all viruses could be detected in infected mosquitoes on FTA cards either individually or in pools with uninfected mosquitoes, and stored for up to 28 days. Importantly, there was only a minimal decrease in RNA levels in mosquitoes between days 0 and 28, indicating that viral RNA was relatively stable on the cards. FTA cards thus provide a mechanism for storing potentially infected mosquitoes collected in the field and transporting them to a central diagnostic facility for virus detection. PMID:28500814

Higher Mosquito Production in Low-Income Neighborhoods of Baltimore and Washington, DC: Understanding Ecological Drivers and Mosquito-Borne Disease Risk in Temperate Cities

PubMed Central

LaDeau, Shannon L.; Leisnham, Paul T.; Biehler, Dawn; Bodner, Danielle

2013-01-01

Mosquito-vectored pathogens are responsible for devastating human diseases and are (re)emerging in many urban environments. Effective mosquito control in urban landscapes relies on improved understanding of the complex interactions between the ecological and social factors that define where mosquito populations can grow. We compared the density of mosquito habitat and pupae production across economically varying neighborhoods in two temperate U.S. cities (Baltimore, MD and Washington, DC). Seven species of mosquito larvae were recorded. The invasive Aedes albopictus was the only species found in all neighborhoods. Culex pipiens, a primary vector of West Nile virus (WNV), was most abundant in Baltimore, which also had more tire habitats. Both Culex and Aedes pupae were more likely to be sampled in neighborhoods categorized as being below median income level in each city and Aedes pupae density was also greater in container habitats found in these lower income neighborhoods. We infer that lower income residents may experience greater exposure to potential disease vectors and Baltimore residents specifically, were at greater risk of exposure to the predominant WNV vector. However, we also found that resident-reported mosquito nuisance was not correlated with our measured risk index, indicating a potentially important mismatch between motivation needed to engage participation in control efforts and the relative importance of control among neighborhoods. PMID:23583963

The influence of diet on the use of near-infrared spectroscopy to determine the age of female Aedes aegypti mosquitoes

USDA-ARS?s Scientific Manuscript database

Interventions targeting adult mosquitoes are used to combat transmission of vector-borne diseases, including dengue. Without available vaccines, targeting the primary vector, Aedes aegypti, is essential to prevent transmission. Older mosquitoes (>/='7 days) are of greatest epidemiological significan...

An Analysis of Diet Quality, How It Controls Fatty Acid Profiles, Isotope Signatures and Stoichiometry in the Malaria Mosquito Anopheles arabiensis

PubMed Central

Hood-Nowotny, Rebecca; Schwarzinger, Bettina; Schwarzinger, Clemens; Soliban, Sharon; Madakacherry, Odessa; Aigner, Martina; Watzka, Margarete; Gilles, Jeremie

2012-01-01

Background Knowing the underlying mechanisms of mosquito ecology will ensure effective vector management and contribute to the overall goal of malaria control. Mosquito populations show a high degree of population plasticity in response to environmental variability. However, the principle factors controlling population size and fecundity are for the most part unknown. Larval habitat and diet play a crucial role in subsequent mosquito fitness. Developing the most competitive insects for sterile insect technique programmes requires a “production” orientated perspective, to deduce the most effective larval diet formulation; the information gained from this process offers us some insight into the mechanisms and processes taking place in natural native mosquito habitats. Methodology/Principal Findings Fatty acid profiles and de-novo or direct assimilation pathways, of whole-individual mosquitoes reared on a range of larval diets were determined using pyrolysis gas chromatograph/mass spectrometry. We used elemental analysis and isotope ratio mass spectrometry to measure individual-whole-body carbon, nitrogen and phosphorous values and to assess the impact of dietary quality on subsequent population stoichiometry, size, quality and isotopic signature. Diet had the greatest impact on fatty acid (FA) profiles of the mosquitoes, which exhibited a high degree of dietary routing, characteristic of generalist feeders. De-novo synthesis of a number of important FAs was observed. Mosquito C:N stoichiometry was fixed in the teneral stage. Dietary N content had significant influence on mosquito size, and P was shown to be a flexible pool which limited overall population size. Conclusions/Significance Direct routing of FAs was evident but there was ubiquitous de-novo synthesis suggesting mosquito larvae are competent generalist feeders capable of survival on diet with varying characteristics. It was concluded that nitrogen availability in the larval diet controlled teneral

Relationships between anopheline mosquitoes and topography in West Timor and Java, Indonesia.

PubMed

Ndoen, Ermi; Wild, Clyde; Dale, Pat; Sipe, Neil; Dale, Mike

2010-08-26

Malaria is a serious health issue in Indonesia. Mosquito control is one aspect of an integrated malaria management programme. To focus resources on priority areas, information is needed about the vectors and their habitats. This research aimed to identify the relationship between anopheline mosquitoes and topography in West Timor and Java. Study areas were selected in three topographic types in West Timor and Java. These were: coastal plain, hilly (rice field) and highland. Adult mosquitoes were captured landing on humans identified to species level and counted. Eleven species were recorded, four of which were significant for malaria transmission: Anopheles aconitus, Anopheles barbirostris, Anopheles subpictus and Anopheles sundaicus. Each species occupied different topographies, but only five were significantly associated: Anopheles annularis, Anopheles vagus and Anopheles subpictus (Java only) with hilly rice fields; Anopheles barbirostris, Anopheles maculatus and Anopheles subpictus (West Timor only) with coastal areas. Information on significant malaria vectors associated with specific topography is useful for planning the mosquito control aspect of malaria management.

Capitalizing on Citizen Science Data for Validating Models and Generating Hypotheses Describing Meteorological Drivers of Mosquito-Borne Disease Risk

NASA Astrophysics Data System (ADS)

Boger, R. A.; Low, R.; Paull, S.; Anyamba, A.; Soebiyanto, R. P.

2017-12-01

Temperature and precipitation are important drivers of mosquito population dynamics, and a growing set of models have been proposed to characterize these relationships. Validation of these models, and development of broader theories across mosquito species and regions could nonetheless be improved by comparing observations from a global dataset of mosquito larvae with satellite-based measurements of meteorological variables. Citizen science data can be particularly useful for two such aspects of research into the meteorological drivers of mosquito populations: i) Broad-scale validation of mosquito distribution models and ii) Generation of quantitative hypotheses regarding changes to mosquito abundance and phenology across scales. The recently released GLOBE Observer Mosquito Habitat Mapper (GO-MHM) app engages citizen scientists in identifying vector taxa, mapping breeding sites and decommissioning non-natural habitats, and provides a potentially useful new tool for validating mosquito ubiquity projections based on the analysis of remotely sensed environmental data. Our early work with GO-MHM data focuses on two objectives: validating citizen science reports of Aedes aegypti distribution through comparison with accepted scientific data sources, and exploring the relationship between extreme temperature and precipitation events and subsequent observations of mosquito larvae. Ultimately the goal is to develop testable hypotheses regarding the shape and character of this relationship between mosquito species and regions.

Effects of human and mosquito migrations on the dynamical behavior of the spread of malaria

NASA Astrophysics Data System (ADS)

Beay, Lazarus Kalvein; Kasbawati, Toaha, Syamsuddin

2017-03-01

Malaria is one of infectious diseases which become the main public health problem especially in Indonesia. Mathematically, the spread of malaria can be modeled to predict the outbreak of the disease. This research studies about mathematical model of the spread of malaria which takes into consideration the migration of human and mosquito populations. By determining basic reproduction number of the model, we analyze effects of migration parameter with respect to the reduction of malaria outbreak. Sensitivity analysis of basic reproduction number shows that mosquito migration has greater effect in reducing the outbreak of malaria compared with human migration. Basic reproduction number of the model is monotonically decreasing as mosquito migration increasing. We then confirm the analytic result by doing numerical simulation. The results show that migrations in human and mosquito populations have big influences in eliminating and eradicating the disease from the system.

Assessing the Susceptibility Status of Mosquitoes (Diptera: Culicidae) in a Dirofilariasis Focus, Northwestern Iran

PubMed Central

Ataie, Abolfazl; Moosa-Kazemi, Seyed Hassan; Vatandoost, Hassan; Yaghoobi-Ershadi, Mohammad Reza; Bakhshi, Hasan; Anjomruz, Mehdi

2015-01-01

Background: Mosquitoes are considered as the vectors of dirofilariasis and some vector borne disease in Iran. The objective of this study was to determine the susceptibility level of the vectors to various insecticides recommended by WHO for any control measures in an endemic area in northwestern Iran. Methods: Mosquito larval and adult collections were carried out using different methods provided by WHO including dipping and hand catch techniques. The susceptibility level was assessed to DDT 4%, malathion 5%, propoxur 0.1%, deltamethrin 0.05% and lambda-cyhalothrin 0.05%. Results: Totally, 749 adults and 5060 larvae of Culicidae mosquitoes were collected comprising seven species of adult and larvae, including: Anopheles claviger, An. maculipennis, An. sacharovi, Culex hortensis, Cx. pipiens, Cx. theileri and Culiseta longiaerolata. Frequency of larvae and adults of An. maculipennis was very low, so susceptibility tests on this species did not performed. Results showed that Cx. theileri, Cs. longiaerolata and Cx. pipiens were resistant to DDT 4%, lambda-cyhalothrin 0.05%, and propoxur 0.1% whereas found tolerant to deltamethrin 0.05% and malathion 5%. The LT50 and LT90 values for five insecticides were calculated. Conclusion: We suggest the same study in different parts of the world to obtain the data due to bionomic and susceptibility status of dirofilariasis vectors. This information will help the health authorities for monitoring and evaluation of control measures. PMID:26114140

Spatial autocorrelation of West Nile virus vector mosquito abundance in a seasonally wet suburban environment

NASA Astrophysics Data System (ADS)

Trawinski, P. R.; Mackay, D. S.

2009-03-01

The objective of this study is to quantify and model spatial dependence in mosquito vector populations and develop predictions for unsampled locations using geostatistics. Mosquito control program trap sites are often located too far apart to detect spatial dependence but the results show that integration of spatial data over time for Cx. pipiens-restuans and according to meteorological conditions for Ae. vexans enables spatial analysis of sparse sample data. This study shows that mosquito abundance is spatially correlated and that spatial dependence differs between Cx. pipiens-restuans and Ae. vexans mosquitoes.

Nature, Nurture and Evolution of Intra-Species Variation in Mosquito Arbovirus Transmission Competence

PubMed Central

Tabachnick, Walter J.

2013-01-01

Mosquitoes vary in their competence or ability to transmit arthropod-borne viruses (arboviruses). Many arboviruses cause disease in humans and animals. Identifying the environmental and genetic causes of variation in mosquito competence for arboviruses is one of the great challenges in public health. Progress identifying genetic (nature) and environmental (nurture) factors influencing mosquito competence for arboviruses is reviewed. There is great complexity in the various traits that comprise mosquito competence. The complex interactions between environmental and genetic factors controlling these traits and the factors shaping variation in Nature are largely unknown. The norms of reaction of specific genes influencing competence, their distributions in natural populations and the effects of genetic polymorphism on phenotypic variation need to be determined. Mechanisms influencing competence are not likely due to natural selection because of the direct effects of the arbovirus on mosquito fitness. More likely the traits for mosquito competence for arboviruses are the effects of adaptations for other functions of these competence mechanisms. Determining these other functions is essential to understand the evolution and distributions of competence for arboviruses. This information is needed to assess risk from mosquito-borne disease, predict new mosquito-arbovirus systems, and provide novel strategies to mitigate mosquito-borne arbovirus transmission. PMID:23343982

Nature, nurture and evolution of intra-species variation in mosquito arbovirus transmission competence.

PubMed

Tabachnick, Walter J

2013-01-11

Mosquitoes vary in their competence or ability to transmit arthropod-borne viruses (arboviruses). Many arboviruses cause disease in humans and animals. Identifying the environmental and genetic causes of variation in mosquito competence for arboviruses is one of the great challenges in public health. Progress identifying genetic (nature) and environmental (nurture) factors influencing mosquito competence for arboviruses is reviewed. There is great complexity in the various traits that comprise mosquito competence. The complex interactions between environmental and genetic factors controlling these traits and the factors shaping variation in Nature are largely unknown. The norms of reaction of specific genes influencing competence, their distributions in natural populations and the effects of genetic polymorphism on phenotypic variation need to be determined. Mechanisms influencing competence are not likely due to natural selection because of the direct effects of the arbovirus on mosquito fitness. More likely the traits for mosquito competence for arboviruses are the effects of adaptations for other functions of these competence mechanisms. Determining these other functions is essential to understand the evolution and distributions of competence for arboviruses. This information is needed to assess risk from mosquito-borne disease, predict new mosquito-arbovirus systems, and provide novel strategies to mitigate mosquito-borne arbovirus transmission.

New insights into HCV replication in original cells from Aedes mosquitoes.

PubMed

Fallecker, Catherine; Caporossi, Alban; Rechoum, Yassine; Garzoni, Frederic; Larrat, Sylvie; François, Olivier; Fender, Pascal; Morand, Patrice; Berger, Imre; Petit, Marie-Anne; Drouet, Emmanuel

2017-08-22

The existing literature about HCV association with, and replication in mosquitoes is extremely poor. To fill this gap, we performed cellular investigations aimed at exploring (i) the capacity of HCV E1E2 glycoproteins to bind on Aedes mosquito cells and (ii) the ability of HCV serum particles (HCVsp) to replicate in these cell lines. First, we used purified E1E2 expressing baculovirus-derived HCV pseudo particles (bacHCVpp) so we could investigate their association with mosquito cell lines from Aedes aegypti (Aag-2) and Aedes albopictus (C6/36). We initiated a series of infections of both mosquito cells (Ae aegypti and Ae albopictus) with the HCVsp (Lat strain - genotype 3) and we observed the evolution dynamics of viral populations within cells over the course of infection via next-generation sequencing (NGS) experiments. Our binding assays revealed bacHCVpp an association with the mosquito cells, at comparable levels obtained with human hepatocytes (HepaRG cells) used as a control. In our infection experiments, the HCV RNA (+) were detectable by RT-PCR in the cells between 21 and 28 days post-infection (p.i.). In human hepatocytes HepaRG and Ae aegypti insect cells, NGS experiments revealed an increase of global viral diversity with a selection for a quasi-species, suggesting a structuration of the population with elimination of deleterious mutations. The evolutionary pattern in Ae albopictus insect cells is different (stability of viral diversity and polymorphism). These results demonstrate for the first time that natural HCV could really replicate within Aedes mosquitoes, a discovery which may have major consequences for public health as well as in vaccine development.

Methionine as a safe and effective novel biorational mosquito larvicide.

PubMed

Weeks, Emma N I; Baniszewski, Julie; Gezan, Salvador A; Allan, Sandra A; Cuda, James P; Stevens, Bruce R

2018-06-11

Mosquito larvicides provide a source-reduction strategy to diminish adult females that bite and potentially spread pathogens. Demands are mounting for new and innovative effective biorational larvicides, due to the development of resistance to some currently utilized mosquito larvicides, undesirable non-target effects, and U.S. Environmental Protection Agency (EPA) restrictions. Methionine is a human nutrient essential amino acid that unexpectedly has been shown to be a valuable safe pest management tool against select insect pests that possess alkaline gut physiology. The present study evaluated larvicidal toxicity of methionine in several pestiferous mosquito (Diptera: Culicidae) genera. Concentration-dependent DL-methionine kinetics assays of survival and pupation were conducted in larvae of Aedes albopictus Skuse, Anopheles quadrimaculatus Say, and Culex tarsalis Coquillett in glass jars. Higher concentrations of DL-methionine yielded 100% mortality for all test species and prevented pupation at a rate equivalent to Bacillus thuringiensis israelensis (Bti) treatments. Concentration kinetics indicated that An. quadrimaculatus was 10-fold more sensitive to DL-methionine than Ae. albopictus and Cx. tarsalis. EPA regulations currently exempt methionine in pesticide formulations applied to agricultural crops. This study demonstrates that methionine is a highly effective mosquito larvicide that can provide a beneficial new biorational, environmentally sustainable tool to control pestiferous mosquitoes. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Comparative estimates of density and species diversity in adult mosquito populations landing on a human subject and captured using light and suction traps.

USDA-ARS?s Scientific Manuscript database

Comparative responses of 21 species of mosquitoes to light traps (LT) and suction traps (ST) and captured using the human landing collection method (HL) varied in accordance with collection technique but data analyses for most species revealed significant interaction between collection method and th...

Factors influencing stakeholders attitudes toward genetically modified aedes mosquito.

PubMed

Amin, Latifah; Hashim, Hasrizul

2015-06-01

Dengue fever is a debilitating and infectious disease that could be life-threatening. It is caused by the dengue virus which affects millions of people in the tropical area. Currently, there is no cure for the disease as there is no vaccine available. Thus, prevention of the vector population using conventional methods is by far the main strategy but has been found ineffective. A genetically modified (GM) mosquito is among the favoured alternatives to curb dengue fever in Malaysia. Past studies have shown that development and diffusion of gene technology products depends heavily upon public acceptance. The purpose of this study is to identify the relevant factors influencing stakeholders' attitudes toward the GM Aedes mosquito and to analyse the relationships between all the factors using the structural equation model. A survey was carried out on 509 respondents from various stakeholder groups in the Klang Valley region of Malaysia. Results of the survey have confirmed that public perception towards complex issues such as gene technology should be seen as a multi-faceted process. The perceived benefit-perceived risk balance is very important in determining the most predominant predictor of attitudes toward a GM mosquito. In this study the stakeholders perceived the benefit of the GM mosquito as outweighing its risk, translating perceived benefit as the most important direct predictor of attitudes toward the GM mosquito. Trust in key players has a direct influence on attitudes toward the GM mosquito while moral concern exhibited an indirect influence through perceived benefits. Other factors such as attitudes toward technology and nature were also indirect predictors of attitudes toward the GM mosquito while religiosity and engagement did not exhibited any significant roles. The research findings serve as a useful database to understand public acceptance and the social construct of public attitudes towards the GM mosquito to combat dengue.

Stable Isotope Analysis Reveals Detrital Resource Base Sources of the Tree Hole Mosquito, Aedes triseriatus

PubMed Central

Kaufman, Michael G.; Pelz-Stelinski, Kirsten S.; Yee, Donald A.; Juliano, Steven A.; Ostrom, Peggy H.; Walker, Edward D.

2010-01-01

1. Detritus that forms the basis for mosquito production in tree hole ecosystems can vary in type and timing of input. We investigated the contributions of plant- and animal-derived detritus to the biomass of Aedes triseriatus (Say) pupae and adults by using stable isotope (15N and 13C) techniques in lab experiments and field collections. 2. Lab-reared mosquito isotope values reflected their detrital resource base, providing a clear distinction between mosquitoes reared on plant or animal detritus. 3. Isotope values from field-collected pupae were intermediate between what would be expected if a single (either plant or animal) detrital source dominated the resource base. However, mosquito isotope values clustered most closely with plant-derived values, and a mixed feeding model analysis indicated tree floral parts contributed approximately 80% of mosquito biomass. The mixed model also indicated that animal detritus contributed approximately 30% of mosquito tissue nitrogen. 4. Pupae collected later in the season generally had isotope values that were consistent with an increased contribution from animal detritus, suggesting this resource became more nutritionally important for mosquitoes as plant inputs declined over the summer. PMID:21132121

Free boundary models for mosquito range movement driven by climate warming.

PubMed

Bao, Wendi; Du, Yihong; Lin, Zhigui; Zhu, Huaiping

2018-03-01

As vectors, mosquitoes transmit numerous mosquito-borne diseases. Among the many factors affecting the distribution and density of mosquitoes, climate change and warming have been increasingly recognized as major ones. In this paper, we make use of three diffusive logistic models with free boundary in one space dimension to explore the impact of climate warming on the movement of mosquito range. First, a general model incorporating temperature change with location and time is introduced. In order to gain insights of the model, a simplified version of the model with the change of temperature depending only on location is analyzed theoretically, for which the dynamical behavior is completely determined and presented. The general model can be modified into a more realistic one of seasonal succession type, to take into account of the seasonal changes of mosquito movements during each year, where the general model applies only for the time period of the warm seasons of the year, and during the cold season, the mosquito range is fixed and the population is assumed to be in a hibernating status. For both the general model and the seasonal succession model, our numerical simulations indicate that the long-time dynamical behavior is qualitatively similar to the simplified model, and the effect of climate warming on the movement of mosquitoes can be easily captured. Moreover, our analysis reveals that hibernating enhances the chances of survival and successful spreading of the mosquitoes, but it slows down the spreading speed.

The Effectiveness of Asian Bush Mosquito (Aedes japonicus japonicus) Control Actions in Colonised Peri-urban Areas in the Netherlands

PubMed Central

Ibañez-Justicia, A; Teekema, S; den Hartog, W; Jacobs, F; Dik, M; Stroo, A

2018-01-01

Abstract The Asian bush mosquito (Aedes japonicus japonicus (Theobald)) is an invasive mosquito species in Europe. In 2012, it was for the first time detected in the Netherlands, in the municipality of Lelystad. After further research, thousands of specimens were found in the surrounding peri-urban areas of the city. A targeted mosquito control campaign began in 2015 with the objective of reducing populations in locations with the highest concentrations of Ae. japonicus breeding sites: allotment garden complexes. Mosquito control consisted of source reduction combined with application of the larvicide Vectomax in breeding sites. At eight complexes, mosquito control effectiveness has been systematically measured by sampling larvae from breeding sites. Six measurements were performed between 2015 and 2016. Results show that the effectiveness of mosquito control actions was similar in all treated allotment gardens and resulted in a significant reduction in Ae. japonicus larval abundance. Rain barrels at the allotments represent the most frequent breeding site in Lelystad, but every water filled artificial container is a potential breeding site for the species. Ae. japonicus was not found in the samples taken in other allotment gardens in the province of Flevoland; however, the collection methodology used proven to be effective in detecting this species when it has newly colonized surrounding areas. Targeted mosquito control actions at the breeding sites are crucial for successful reduction of populations of an invasive mosquito species, and systematic measurements of the effectiveness, is in this case, the base to understand the dynamics of Ae. japonicus populations after mosquito control. PMID:29452383

Characterization of Carbonic Anhydrase 9 in the Alimentary Canal of Aedes aegypti and Its Relationship to Homologous Mosquito Carbonic Anhydrases

PubMed Central

Dixon, Daniel P.; Van Ekeris, Leslie; Linser, Paul J.

2017-01-01

In the mosquito midgut, luminal pH regulation and cellular ion transport processes are important for the digestion of food and maintenance of cellular homeostasis. pH regulation in the mosquito gut is affected by the vectorial movement of the principal ions including bicarbonate/carbonate and protons. As in all metazoans, mosquitoes employ the product of aerobic metabolism carbon dioxide in its bicarbonate/carbonate form as one of the major buffers of cellular and extracellular pH. The conversion of metabolic carbon dioxide to bicarbonate/carbonate is accomplished by a family of enzymes encoded by the carbonic anhydrase gene family. This study characterizes Aedes aegypti carbonic anhydrases using bioinformatic, molecular, and immunohistochemical methods. Our analyses show that there are fourteen Aedes aegypti carbonic anhydrase genes, two of which are expressed as splice variants. The carbonic anhydrases were classified as either integral membrane, peripheral membrane, mitochondrial, secreted, or soluble cytoplasmic proteins. Using polymerase chain reaction and Western blotting, one of the carbonic anhydrases, Aedes aegypti carbonic anhydrase 9, was analyzed and found in each life stage, male/female pupae, male/female adults, and in the female posterior midgut. Next, carbonic anhydrase 9 was analyzed in larvae and adults using confocal microscopy and was detected in the midgut regions. According to our analyses, carbonic anhydrase 9 is a soluble cytoplasmic enzyme found in the alimentary canal of larvae and adults and is expressed throughout the life cycle of the mosquito. Based on previous physiological analyses of adults and larvae, it appears AeCA9 is one of the major carbonic anhydrases involved in producing bicarbonate/carbonate which is involved in pH regulation and ion transport processes in the alimentary canal. Detailed understanding of the molecular bases of ion homeostasis in mosquitoes will provide targets for novel mosquito control strategies into the

Levels of insecticide resistance to deltamethrin, malathion, and temephos, and associated mechanisms in Aedes aegypti mosquitoes from the Guadeloupe and Saint Martin islands (French West Indies).

PubMed

Goindin, Daniella; Delannay, Christelle; Gelasse, Andric; Ramdini, Cédric; Gaude, Thierry; Faucon, Frédéric; David, Jean-Philippe; Gustave, Joël; Vega-Rua, Anubis; Fouque, Florence

2017-02-10

In the Guadeloupe and Saint Martin islands, Aedes aegypti mosquitoes are the only recognized vectors of dengue, chikungunya, and Zika viruses. For around 40 years, malathion was used as a mosquito adulticide and temephos as a larvicide. Since the European Union banned the use of these two insecticide molecules in the first decade of the 21st century, deltamethrin and Bacillus thuringiensis var. israelensis are the remaining adulticide and larvicide, respectively, used in Guadeloupe. In order to improve the management of vector control activities in Guadeloupe and Saint Martin, we investigated Ae. aegypti resistance to and mechanisms associated with deltamethrin, malathion, and temephos. Ae. aegypti mosquitoes were collected from six different localities of Guadeloupe and Saint Martin. Larvae were used for malathion and temephos bioassays, and adult mosquitoes for deltamethrin bioassays, following World Health Organization recommendations. Knockdown resistance (Kdr) genotyping for V1016I and F1534C mutations, and expression levels of eight enzymes involved in detoxification mechanisms were examined in comparison with the susceptible reference Bora Bora strain. Resistance ratios (RR 50 ) calculated for Ae. aegypti larvae showed high resistance levels to temephos (from 8.9 to 33.1-fold) and low resistance levels to malathion (from 1.7 to 4.4-fold). Adult females displayed moderate resistance levels to deltamethrin regarding the time necessary to affect 50% of individuals, varying from 8.0 to 28.1-fold. Molecular investigations on adult mosquitoes showed high resistant allele frequencies for V1016I and F1534C (from 85 to 96% and from 90 to 98%, respectively), as well as an overexpression of the glutathione S-transferase gene, GSTe2, the carboxylesterase CCEae3a, and the cytochrome genes 014614, CYP6BB2, CYP6M11, and CYP9J23. Ae. aegypti populations from Guadeloupe and Saint Martin exhibit multiple resistance to organophosphates (temephos and malathion), and

Diversity of Mosquitoes (Diptera: Culicidae) Attracted to Human Subjects in Rubber Plantations, Secondary Forests, and Villages in Luang Prabang Province, Northern Lao PDR.

PubMed

Tangena, Julie-Anne A; Thammavong, Phoutmany; Malaithong, Naritsara; Inthavong, Thavone; Ouanesamon, Phuthasone; Brey, Paul T; Lindsay, Steve W

2017-11-07

The impact of the rapid expansion of rubber plantations in South-East Asia on mosquito populations is uncertain. We compared the abundance and diversity of adult mosquitoes using human-baited traps in four typical rural habitats in northern Lao PDR: secondary forests, immature rubber plantations, mature rubber plantations, and villages. Generalized estimating equations were used to explore differences in mosquito abundance between habitats, and Simpson's diversity index was used to measure species diversity. Over nine months, 24,927 female mosquitoes were collected, including 51 species newly recorded in Lao PDR. A list of the 114 mosquito species identified is included. More mosquitoes, including vector species, were collected in the secondary forest than immature rubber plantations (rainy season, odds ratio [OR] 0.33, 95% confidence interval [CI] 0.31-0.36; dry season, 0.46, 95% CI 0.41-0.51), mature rubber plantations (rainy season, OR 0.25, 95% CI 0.23-0.27; dry season, OR 0.25, 95% CI 0.22-0.28), and villages (rainy season, OR 0.13, 95% CI 0.12-0.14; dry season, 0.20, 95% CI 0.18-0.23). All habitats showed high species diversity (Simpson's indexes between 0.82-0.86) with vectors of dengue, Japanese encephalitis (JE), lymphatic filariasis, and malaria. In the secondary forests and rubber plantations, Aedes albopictus (Skuse), a dengue vector, was the dominant mosquito species, while in the villages, Culex vishnui (Theobald), a JE vector, was most common. This study has increased the overall knowledge of mosquito fauna in Lao PDR. The high abundance of Ae. albopictus in natural and man-made forests warrants concern, with vector control measures currently only implemented in cities and villages. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Open release of male mosquitoes infected with a wolbachia biopesticide: field performance and infection containment.

PubMed

O'Connor, Linda; Plichart, Catherine; Sang, Ayo Cheong; Brelsfoard, Corey L; Bossin, Hervé C; Dobson, Stephen L

2012-01-01

Lymphatic filariasis (LF) is a globally significant disease, with 1.3 billion persons in 83 countries at risk. A coordinated effort of administering annual macrofilaricidal prophylactics to the entire at-risk population has succeeded in impacting and eliminating LF transmission in multiple regions. However, some areas in the South Pacific are predicted to persist as transmission sites, due in part to the biology of the mosquito vector, which has led to a call for additional tools to augment drug treatments. Autocidal strategies against mosquitoes are resurging in the effort against invasive mosquitoes and vector borne disease, with examples that include field trials of genetically modified mosquitoes and Wolbachia population replacement. However, critical questions must be addressed in anticipation of full field trials, including assessments of field competitiveness of transfected males and the risk of unintended population replacement. We report the outcome of field experiments testing a strategy that employs Wolbachia as a biopesticide. The strategy is based upon Wolbachia-induced conditional sterility, known as cytoplasmic incompatibility, and the repeated release of incompatible males to suppress a population. A criticism of the Wolbachia biopesticide approach is that unintended female release or horizontal Wolbachia transmission can result in population replacement instead of suppression. We present the outcome of laboratory and field experiments assessing the competitiveness of transfected males and their ability to transmit Wolbachia via horizontal transmission. The results demonstrate that Wolbachia-transfected Aedes polynesiensis males are competitive under field conditions during a thirty-week open release period, as indicated by mark, release, recapture and brood-hatch failure among females at the release site. Experiments demonstrate the males to be 'dead end hosts' for Wolbachia and that methods were adequate to prevent population replacement at the

Comparison of Model Predictions and Laboratory Observations of Transgene Frequencies in Continuously-Breeding Mosquito Populations

PubMed Central

Valerio, Laura; North, Ace; Collins, C. Matilda; Mumford, John D.; Facchinelli, Luca; Spaccapelo, Roberta; Benedict, Mark Q.

2016-01-01

The persistence of transgenes in the environment is a consideration in risk assessments of transgenic organisms. Combining mathematical models that predict the frequency of transgenes and experimental demonstrations can validate the model predictions, or can detect significant biological deviations that were neither apparent nor included as model parameters. In order to assess the correlation between predictions and observations, models were constructed to estimate the frequency of a transgene causing male sexual sterility in simulated populations of a malaria mosquito Anopheles gambiae that were seeded with transgenic females at various proportions. Concurrently, overlapping-generation laboratory populations similar to those being modeled were initialized with various starting transgene proportions, and the subsequent proportions of transgenic individuals in populations were determined weekly until the transgene disappeared. The specific transgene being tested contained a homing endonuclease gene expressed in testes, I-PpoI, that cleaves the ribosomal DNA and results in complete male sexual sterility with no effect on female fertility. The transgene was observed to disappear more rapidly than the model predicted in all cases. The period before ovipositions that contained no transgenic progeny ranged from as little as three weeks after cage initiation to as long as 11 weeks. PMID:27669312

Malaria vector populations across ecological zones in Guinea Conakry and Mali, West Africa.

PubMed

Coulibaly, Boubacar; Kone, Raymond; Barry, Mamadou S; Emerson, Becky; Coulibaly, Mamadou B; Niare, Oumou; Beavogui, Abdoul H; Traore, Sekou F; Vernick, Kenneth D; Riehle, Michelle M

2016-04-08

Malaria remains a pervasive public health problem in sub-Saharan West Africa. Here mosquito vector populations were explored across four sites in Mali and the Republic of Guinea (Guinea Conakry). The study samples the major ecological zones of malaria-endemic regions in West Africa within a relatively small distance. Mosquito vectors were sampled from larval pools, adult indoor resting sites, and indoor and outdoor human-host seeking adults. Mosquitoes were collected at sites spanning 350 km that represented arid savannah, humid savannah, semi-forest and deep forest ecological zones, in areas where little was previously known about malaria vector populations. 1425 mosquito samples were analysed by molecular assays to determine species, genetic attributes, blood meal sources and Plasmodium infection status. Anopheles gambiae and Anopheles coluzzii were the major anophelines represented in all collections across the ecological zones, with A. coluzzii predominant in the arid savannah and A. gambiae in the more humid sites. The use of multiple collection methodologies across the sampling sites allows assessment of potential collection bias of the different methods. The L1014F kdr insecticide resistance mutation (kdr-w) is found at high frequency across all study sites. This mutation appears to have swept almost to fixation, from low frequencies 6 years earlier, despite the absence of widespread insecticide use for vector control. Rates of human feeding are very high across ecological zones, with only small fractions of animal derived blood meals in the arid and humid savannah. About 30 % of freshly blood-fed mosquitoes were positive for Plasmodium falciparum presence, while the rate of mosquitoes with established infections was an order of magnitude lower. The study represents detailed vector characterization from an understudied area in West Africa with endemic malaria transmission. The deep forest study site includes the epicenter of the 2014 Ebola virus epidemic

[Biological factors influencing infectious diseases transmitted by invasive species of mosquitoes].

PubMed

Boštíková, Vanda; Pasdiorová, Markéta; Marek, Jan; Prášil, Petr; Salavec, Miloslav; Sleha, Radek; Střtítecká, Hana; Blažek, Pavel; Hanovcová, Irena; Šošovičková, Renáta; Špliňo, Milan; Smetana, Jan; Chlíbek, Roman; Hytych, Václav; Kuča, Kamil; Boštík, Pavel

2016-06-01

Studies focused on arbovirus diseases transmitted by invasive species of mosquitoes have become increasingly significant in recent years, due to the fact that these vectors have successfully migrated to Europe and become established in the region. Mosquitoes, represented by more than 3 200 species, occur naturally worldwide, except in Antarctica. They feed on the blood of warm-blooded animals and by this route, they are capable of transmitting dangerous diseases. Some species can travel a distance of 10 km per night and can fly continuously for up to 4 hours at a speed of 1-2 km/h. Most species are active at night, in the evening or morning. It usually takes a mosquito female about 50 seconds to penetrate the skin of mammals and the subsequent blood meal usually takes about 2.5 minutes. Mosquitoes live for several weeks or months, depending on the environmental conditions. The VectorNet project is a European network of information exchange and sharing of data relating to the geographical distribution of arthropod vectors and transmission of infectious agents between human populations and animals. It aims at the development of strategic plans and vaccination policies which are the main tasks of this time, as well as the development and application of new disinfectants to control vector populations.

Arbovirus Prevalence in Mosquitoes, Kenya

PubMed Central

Sutherland, Laura J.; Muiruri, Samuel; Muchiri, Eric M.; Gray, Laurie R.; Zimmerman, Peter A.; Hise, Amy G.; King, Charles H.

2011-01-01

Few studies have investigated the many mosquito species that harbor arboviruses in Kenya. During the 2006–2007 Rift Valley fever outbreak in North Eastern Province, Kenya, exophilic mosquitoes were collected from homesteads within 2 affected areas: Gumarey (rural) and Sogan-Godud (urban). Mosquitoes (n = 920) were pooled by trap location and tested for Rift Valley fever virus and West Nile virus. The most common mosquitoes trapped belonged to the genus Culex (75%). Of 105 mosquito pools tested, 22% were positive for Rift Valley fever virus, 18% were positive for West Nile virus, and 3% were positive for both. Estimated mosquito minimum infection rates did not differ between locations. Our data demonstrate the local abundance of mosquitoes that could propagate arboviral infections in Kenya and the high prevalence of vector arbovirus positivity during a Rift Valley fever outbreak. PMID:21291594

The ecology of vector snail habitats and mosquito breeding-places

PubMed Central

Muirhead-Thomson, R. C.

1958-01-01

The ecology of freshwater snails—in particular those which act as intermediate hosts of bilharziasis—is reviewed in the light of the much more extensive knowledge available on the breeding-places of anopheline mosquitos. Experimental ecological methods are recommended for the field and laboratory investigation of a number of common problems involved in the study of snail habitats and mosquito breeding-places. Among the environmental factors discussed are temperature, oxygen concentration, water movement, pollution and salinity. Sampling methods for estimating populations of both snails and mosquito larvae are also described. An attempt is made to show how malacologists and entomologists alike would benefit from improved facilities for keeping abreast of general developments in the wider field of freshwater ecology. PMID:13596888

Anopheline and culicine mosquitoes are not repelled by surfaces treated with the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana.

PubMed

Mnyone, Ladslaus L; Koenraadt, Constantianus Jm; Lyimo, Issa N; Mpingwa, Monica W; Takken, Willem; Russell, Tanya L

2010-08-27

Entomopathogenic fungi, Metarhizium anisopliae and Beauveria bassiana, are promising bio-pesticides for application against adult malaria mosquito vectors. An understanding of the behavioural responses of mosquitoes towards these fungi is necessary to guide development of fungi beyond the 'proof of concept' stage and to design suitable intervention tools. Here we tested whether oil-formulations of the two fungi could be detected and avoided by adult Anopheles gambiae s.s., Anopheles arabiensis and Culex quinquefasciatus. The bioassays used a glass chamber divided into three compartments (each 250 × 250 × 250 mm): release, middle and stimulus compartments. Netting with or without fungus was fitted in front of the stimulus compartment. Mosquitoes were released and the proportion that entered the stimulus compartment was determined and compared between treatments. Treatments were untreated netting (control 1), netting with mineral oil (control 2) and fungal conidia formulated in mineral oil evaluated at three different dosages (2 × 1010, 4 × 1010 and 8 × 1010 conidia m-2). Neither fungal strain was repellent as the mean proportion of mosquitoes collected in the stimulus compartment did not differ between experiments with surfaces treated with and without fungus regardless of the fungal isolate and mosquito species tested. Our results indicate that mineral-oil formulations of M. anisopliae and B. bassiana were not repellent against the mosquito species tested. Therefore, both fungi are suitable candidates for the further development of tools that aim to control host-seeking or resting mosquitoes using entomopathogenic fungi.

GLOBE Observer Mosquito Habitat Mapper: Geoscience and Public Health Connections

NASA Astrophysics Data System (ADS)

Low, R.; Boger, R. A.

2017-12-01

The global health crisis posed by vector-borne diseases is so great in scope that it is clearly insurmountable without the active help of tens-or hundreds- of thousands of individuals, working to identify and eradicate risk in communities around the world. Mobile devices equipped with data collection capabilities and visualization opportunities are lowering the barrier for participation in data collection efforts. The GLOBE Observer Mosquito Habitat Mapper (MHM) provides citizen scientists with an easy to use mobile platform to identify and locate mosquito breeding sites in their community. The app also supports the identification of vector taxa in the larvae development phase via a built-in key, which provides important information for scientists and public health officials tracking the rate of range expansion of invasive vector species and associated health threats. GO Mosquito is actively working with other citizen scientist programs across the world to ensure interoperability of data through standardization of metadata fields specific to vector monitoring, and through the development of APIs that allow for data exchange and shared data display through a UN-sponsored proof of concept project, Global Mosquito Alert. Avenues of application for mosquito vector data-both directly, by public health entities, and by modelers who employ remotely sensed environmental data to project mosquito population dynamics and epidemic disease will be featured.

Interspecific larval competition between invasive Aedes japonicus and native Aedes triseriatus (Diptera: Culicidae) and adult longevity.

PubMed

Alto, Barry W

2011-03-01

The Asian rock pool mosquito Aedes japonicus (Theobald) inhabits natural and artificial container habitats, some of which are occupied by the native treehole mosquitoAedes triseriatus (Say), a vector of LaCrosse encephalitis virus. A laboratory experiment was used to evaluate the effects of nutrient limitation and interspecific interactions between these species. The goal was to address two related hypotheses. First, interspecific interactions between these species show competitive asymmetry with the invasive mosquito Ae. japonicus being favored over Ae. triseriatus. Second, competitive stress at the larval stage alters adult longevity. There was minimal evidence for competitive asymmetry between these two species. Mosquito and population performance showed clear negative density-dependent effects with similar effects of intra- and interspecific interactions. Only Ae. japonicus development time showed competitive asymmetry over Ae. triseriatus, providing weak support for the first hypothesis. For both species, competition resulted in lower adult longevity compared with low competition, providing support for the second hypothesis. These results suggest both species are similarly affected by intra- and interspecific competition and underscore the importance of the effects of larval competition that continue into adulthood and alter parameters important to transmission of vector-borne diseases.

Morphological studies on adult mosquitoes (Diptera: Culicidae) and first report of the potential Zika virus vector Aedes (Stegomyia) unilineatus (Theobald, 1906) in Iran.

PubMed

Yaghoobi-Ershadi, M R; Doosti, S; Schaffner, F; Moosa-Kazemi, S H; Akbarzadeh, K; Yaghoobi-Ershadi, N

2017-05-01

Beside numerous extensive studies on Anophelinae mosquitoes of Iran, little is known on Aedes species in the country and existing reports are dispersed. The objective of this study was to identify adults of Culicinae species occurring in the Sistan and Baluchestan Province, southeast of Iran, during 2012-2014. Mosquito collections were carried out three times (May-June, September, October-November) in four counties by Centers for Diseases Control (CDC) light traps and human landing catches outdoors and under bed nets baited with carbon dioxide. These trapping were carried out two consecutive nights during the field studies. Several mosquito collections were also conducted with aspirator and pyrethrum spray space catches during the day. A total of 1885 mosquitoes were collected, belonging to 10 species of genus Culex including Cx. pipiens Complex, Cx. laticinctus, Cx. sinaiticus, and Cx. tritaeniorhynchus, one species of the genus Culiseta, Cs. longiareolata, and five species of the genus Aedes, Ae. caspius, Ae. vexans, Ae. detritus, Ae. albopictus, and Ae. unilineatus. Ae. vexans was the dominant species in the area (77.7%). During the study, seven Ae. unilineatus were collected in two villages near the city of Chabahar located in a coastal area; this is the first record for Iran and identification was confirmed by Cytochrome oxidase (COI) sequences analysis. Confirmation of the presence of Ae. unilineatus in the country raises the number of species of the genus Aedes to 12. The detection of this species reveals its probable establishment in the southeast of the country, which has implications for public health such as dengue and Zika infections and requires active entomological surveillance and implementation of adapted vector control measures in the area.

Mosquito species composition and phenology (Diptera, Culicidae) in two German zoological gardens imply different risks of mosquito-borne pathogen transmission.

PubMed

Heym, Eva C; Kampen, Helge; Walther, Doreen

2018-06-01

Due to their large diversity of potential blood hosts, breeding habitats, and resting sites, zoological gardens represent highly interesting places to study mosquito ecology. In order to better assess the risk of mosquito-borne disease-agent transmission in zoos, potential vector species must be known, as well as the communities in which they occur. For this reason, species composition and dynamics were examined in 2016 in two zoological gardens in Germany. Using different methods for mosquito sampling, a total of 2,257 specimens belonging to 20 taxa were collected. Species spectra depended on the collection method but generally differed between the two zoos, while species compositions and relative abundances varied seasonally in both of them. As both sampled zoos were located in the same climatic region and potential breeding sites within the zoos were similar, the differences in mosquito compositions are attributed to immigration of specimens from surrounding landscapes, although the different sizes of the zoos and the different blood host populations available probably also have an impact. Based on the differences in species composition and the various biological characteristics of the species, the risk of certain pathogens to be transmitted must also be expected to differ between the zoos. © 2018 The Society for Vector Ecology.

Adult height, nutrition, and population health

PubMed Central

Perkins, Jessica M.; Subramanian, S.V.; Davey Smith, George

2016-01-01

In this review, the potential causes and consequences of adult height, a measure of cumulative net nutrition, in modern populations are summarized. The mechanisms linking adult height and health are examined, with a focus on the role of potential confounders. Evidence across studies indicates that short adult height (reflecting growth retardation) in low- and middle-income countries is driven by environmental conditions, especially net nutrition during early years. Some of the associations of height with health and social outcomes potentially reflect the association between these environmental factors and such outcomes. These conditions are manifested in the substantial differences in adult height that exist between and within countries and over time. This review suggests that adult height is a useful marker of variation in cumulative net nutrition, biological deprivation, and standard of living between and within populations and should be routinely measured. Linkages between adult height and health, within and across generations, suggest that adult height may be a potential tool for monitoring health conditions and that programs focused on offspring outcomes may consider maternal height as a potentially important influence. PMID:26928678

Evaluating the lethal and pre-lethal effects of a range of fungi against adult Anopheles stephensi mosquitoes.

PubMed

Blanford, Simon; Jenkins, Nina E; Read, Andrew F; Thomas, Matthew B

2012-11-05

Insecticide resistance is seriously undermining efforts to eliminate malaria. In response, research on alternatives to the use of chemical insecticides against adult mosquito vectors has been increasing. Fungal entomopathogens formulated as biopesticides have received much attention and have shown considerable potential. This research has necessarily focused on relatively few fungal isolates in order to 'prove concept'. Further, most attention has been paid to examining fungal virulence (lethality) and not the other properties of fungal infection that might also contribute to reducing transmission potential. Here, a range of fungal isolates were screened to examine variation in virulence and how this relates to additional pre-lethal reductions in feeding propensity. The Asian malaria vector, Anopheles stephensi was exposed to 17 different isolates of entomopathogenic fungi belonging to species of Beauveria bassiana, Metarhizium anisopliae, Metarhizium acridum and Isaria farinosus. Each isolate was applied to a test substrate at a standard dose rate of 1×109 spores ml-1 and the mosquitoes exposed for six hours. Subsequently the insects were removed to mesh cages where survival was monitored over the next 14 days. During this incubation period the mosquitoes' propensity to feed was assayed for each isolate by offering a feeding stimulant at the side of the cage and recording the number probing. Fungal isolates showed a range of virulence to A. stephensi with some causing >80% mortality within 7 days, while others caused little increase in mortality relative to controls over the study period. Similarly, some isolates had a large impact on feeding propensity, causing >50% pre-lethal reductions in feeding rate, whereas other isolates had very little impact. There was clear correlation between fungal virulence and feeding reduction with virulence explaining nearly 70% of the variation in feeding reduction. However, there were some isolates where either feeding decline

The potential for flower nectar to allow mosquito to mosquito transmission of Francisella tularensis.

PubMed

Kenney, Adam; Cusick, Austin; Payne, Jessica; Gaughenbaugh, Anna; Renshaw, Andrea; Wright, Jenna; Seeber, Roger; Barnes, Rebecca; Florjanczyk, Aleksandr; Horzempa, Joseph

2017-01-01

Francisella tularensis is disseminated in nature by biting arthropods such as mosquitoes. The relationship between mosquitoes and F. tularensis in nature is highly ambiguous, due in part to the fact that mosquitoes have caused significant tularemia outbreaks despite being classified as a mechanical vector of F. tularensis. One possible explanation for mosquitoes being a prominent, yet mechanical vector is that these insects feed on flower nectar between blood meals, allowing for transmission of F. tularensis between mosquitoes. Here, we aimed to assess whether F. tularensis could survive in flower nectar. Moreover, we examined if mosquitoes could interact with or ingest and transmit F. tularensis from one source of nectar to another. F. tularensis exhibited robust survivability in flower nectar with concentrations of viable bacteria remaining consistent with the rich growth medium. Furthermore, F. tularensis was able to survive (albeit to a lesser extent) in 30% sucrose (a nectar surrogate) over a period of time consistent with that of a typical flower bloom. Although we observed diminished bacterial survival in the nectar surrogate, mosquitoes that fed on this material became colonized with F. tularensis. Finally, colonized mosquitoes were capable of transferring F. tularensis to a sterile nectar surrogate. These data suggest that flower nectar may be capable of serving as a temporary source of F. tularensis that could contribute to the amplification of outbreaks. Mosquitoes that feed on an infected mammalian host and subsequently feed on flower nectar could deposit some F. tularensis bacteria into the nectar in the process. Mosquitoes subsequently feeding on this nectar source could potentially become colonized by F. tularensis. Thus, the possibility exists that flower nectar may allow for vector-vector transmission of F. tularensis.

Effects of combination of leaf resources on competition in container mosquito larvae.

PubMed

Reiskind, M H; Zarrabi, A A; Lounibos, L P

2012-08-01

Resource diversity is critical to fitness in many insect species, and may determine the coexistence of competitive species and the function of ecosystems. Plant material provides the nutritional base for numerous aquatic systems, yet the consequences of diversity of plant material have not been studied in aquatic container systems important for the production of mosquitoes. To address how diversity in leaf detritus affects container-inhabiting mosquitoes, we examined how leaf species affect competition between two container inhabiting mosquito larvae, Aedes aegypti and Aedes albopictus, that co-occur in many parts of the world. We tested the hypotheses that leaf species changes the outcome of intra- and interspecific competition between these mosquito species, and that combinations of leaf species affect competition in a manner not predictable based upon the response to each leaf species alone (i.e. the response to leaf combinations is non-additive). We find support for our first hypothesis that leaf species can affect competition, evidence that, in general, leaf combination alters competitive interactions, and no support that leaf combination impacts interspecific competition differently than intraspecific competition. We conclude that combinations of leaves increase mosquito production non-additively such that combinations of leaves act synergistically, in general, and result in higher total yield of adult mosquitoes in most cases, although certain leaf combinations for A. albopictus are antagonistic. We also conclude that leaf diversity does not have a different effect on interspecific competition between A. aegypti and A. albopictus, relative to intraspecific competition for each mosquito.

[Physico-chemical signals involved in host localization and in the induction of mosquito bites].

PubMed

Torres-Estrada, José Luis; Rodríguez, Mario H

2003-01-01

Disease vector female mosquitoes respond to physic-chemical signals to localize vertebrate hosts for blood meals. Zoophylic mosquitoes preferentially respond to CO2 and octenol released in the breath and bodily fluids, while anthropophylic mosquitoes respond to lactic acid and a variety of sweat compounds. These compounds are modified by saprophytic microorganisms in the skin sebaceous glands. Other factors present in human dwellings contribute to the integration of microsystems with characteristic odors that have different attraction for mosquitoes, explaining the focalization of malaria transmission in few households in endemic areas. The identification of the chemical attractants and their molecular receptors could be used to complement new methods to attract mosquitoes to traps during epidemiological surveys, to increase their contact with insecticides in control interventions, and for genetic manipulation to divert mosquito bites towards other animal populations. The English version of this paper is available at:http://www.insp.mx/salud/index.html.

Modeling Dynamics of Culex pipiens Complex Populations and Assessing Abatement Strategies for West Nile Virus

PubMed Central

Pawelek, Kasia A.; Hager, Elizabeth J.; Hunt, Gregg J.

2014-01-01

The primary mosquito species associated with underground stormwater systems in the United States are the Culex pipiens complex species. This group represents important vectors of West Nile virus (WNV) throughout regions of the continental U.S. In this study, we designed a mathematical model and compared it with surveillance data for the Cx. pipiens complex collected in Beaufort County, South Carolina. Based on the best fit of the model to the data, we estimated parameters associated with the effectiveness of public health insecticide (adulticide) treatments (primarily pyrethrin products) as well as the birth, maturation, and death rates of immature and adult Cx. pipiens complex mosquitoes. We used these estimates for modeling the spread of WNV to obtain more reliable disease outbreak predictions and performed numerical simulations to test various mosquito abatement strategies. We demonstrated that insecticide treatments produced significant reductions in the Cx. pipiens complex populations. However, abatement efforts were effective for approximately one day and the vector mosquitoes rebounded until the next treatment. These results suggest that frequent insecticide applications are necessary to control these mosquitoes. We derived the basic reproductive number (ℜ0) to predict the conditions under which disease outbreaks are likely to occur and to evaluate mosquito abatement strategies. We concluded that enhancing the mosquito death rate results in lower values of ℜ0, and if ℜ0<1, then an epidemic will not occur. Our modeling results provide insights about control strategies of the vector populations and, consequently, a potential decrease in the risk of a WNV outbreak. PMID:25268229

Heterogeneity, Mixing, and the Spatial Scales of Mosquito-Borne Pathogen Transmission

PubMed Central

Perkins, T. Alex; Scott, Thomas W.; Le Menach, Arnaud; Smith, David L.

2013-01-01

The Ross-Macdonald model has dominated theory for mosquito-borne pathogen transmission dynamics and control for over a century. The model, like many other basic population models, makes the mathematically convenient assumption that populations are well mixed; i.e., that each mosquito is equally likely to bite any vertebrate host. This assumption raises questions about the validity and utility of current theory because it is in conflict with preponderant empirical evidence that transmission is heterogeneous. Here, we propose a new dynamic framework that is realistic enough to describe biological causes of heterogeneous transmission of mosquito-borne pathogens of humans, yet tractable enough to provide a basis for developing and improving general theory. The framework is based on the ecological context of mosquito blood meals and the fine-scale movements of individual mosquitoes and human hosts that give rise to heterogeneous transmission. Using this framework, we describe pathogen dispersion in terms of individual-level analogues of two classical quantities: vectorial capacity and the basic reproductive number, . Importantly, this framework explicitly accounts for three key components of overall heterogeneity in transmission: heterogeneous exposure, poor mixing, and finite host numbers. Using these tools, we propose two ways of characterizing the spatial scales of transmission—pathogen dispersion kernels and the evenness of mixing across scales of aggregation—and demonstrate the consequences of a model's choice of spatial scale for epidemic dynamics and for estimation of , both by a priori model formulas and by inference of the force of infection from time-series data. PMID:24348223

Driven to extinction? The ethics of eradicating mosquitoes with gene-drive technologies.

PubMed

Pugh, Jonathan

2016-09-01

Mosquito-borne diseases represent a significant global disease burden, and recent outbreaks of such diseases have led to calls to reduce mosquito populations. Furthermore, advances in 'gene-drive' technology have raised the prospect of eradicating certain species of mosquito via genetic modification. This technology has attracted a great deal of media attention, and the idea of using gene-drive technology to eradicate mosquitoes has been met with criticism in the public domain. In this paper, I shall dispel two moral objections that have been raised in the public domain against the use of gene-drive technologies to eradicate mosquitoes. The first objection invokes the concept of the 'sanctity of life' in order to claim that we should not drive an animal to extinction. In response, I follow Peter Singer in raising doubts about general appeals to the sanctity of life, and argue that neither individual mosquitoes nor mosquitoes species considered holistically are appropriately described as bearing a significant degree of moral status. The second objection claims that seeking to eradicate mosquitoes amounts to displaying unacceptable degrees of hubris. Although I argue that this objection also fails, I conclude by claiming that it raises the important point that we need to acquire more empirical data about, inter alia, the likely effects of mosquito eradication on the ecosystem, and the likelihood of gene-drive technology successfully eradicating the intended mosquito species, in order to adequately inform our moral analysis of gene-drive technologies in this context. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Local extinction of the Asian tiger mosquito (Aedes albopictus) following rat eradication on Palmyra Atoll.

PubMed

Lafferty, Kevin D; McLaughlin, John P; Gruner, Daniel S; Bogar, Taylor A; Bui, An; Childress, Jasmine N; Espinoza, Magaly; Forbes, Elizabeth S; Johnston, Cora A; Klope, Maggie; Miller-Ter Kuile, Ana; Lee, Michelle; Plummer, Katherine A; Weber, David A; Young, Ronald T; Young, Hillary S

2018-02-01

The Asian tiger mosquito, Aedes albopictus, appears to have been extirpated from Palmyra Atoll following rat eradication. Anecdotal biting reports, collection records, and regular captures in black-light traps showed the species was present before rat eradication. Since then, there have been no biting reports and no captures over 2 years of extensive trapping (black-light and scent traps). By contrast, the southern house mosquito, Culex quinquefasciatus, was abundant before and after rat eradication. We hypothesize that mammals were a substantial and preferred blood meal for Aedes , whereas Culex feeds mostly on seabirds. Therefore, after rat eradication, humans and seabirds alone could not support positive population growth or maintenance of Aedes This seems to be the first documented accidental secondary extinction of a mosquito. Furthermore, it suggests that preferred host abundance can limit mosquito populations, opening new directions for controlling important disease vectors that depend on introduced species like rats. © 2018 The Authors.

Local extinction of the Asian tiger mosquito (Aedes albopictus) following rat eradication on Palmyra Atoll

PubMed Central

McLaughlin, John P.; Bogar, Taylor A.; Bui, An; Childress, Jasmine N.; Espinoza, Magaly; Forbes, Elizabeth S.; Johnston, Cora A.; Klope, Maggie; Miller-ter Kuile, Ana; Lee, Michelle; Plummer, Katherine A.; Weber, David A.; Young, Ronald T.

2018-01-01

The Asian tiger mosquito, Aedes albopictus, appears to have been extirpated from Palmyra Atoll following rat eradication. Anecdotal biting reports, collection records, and regular captures in black-light traps showed the species was present before rat eradication. Since then, there have been no biting reports and no captures over 2 years of extensive trapping (black-light and scent traps). By contrast, the southern house mosquito, Culex quinquefasciatus, was abundant before and after rat eradication. We hypothesize that mammals were a substantial and preferred blood meal for Aedes, whereas Culex feeds mostly on seabirds. Therefore, after rat eradication, humans and seabirds alone could not support positive population growth or maintenance of Aedes. This seems to be the first documented accidental secondary extinction of a mosquito. Furthermore, it suggests that preferred host abundance can limit mosquito populations, opening new directions for controlling important disease vectors that depend on introduced species like rats. PMID:29491026

Local extinction of the Asian tiger mosquito (Aedes albopictus) following rat eradication on Palmyra Atol

USGS Publications Warehouse

Lafferty, Kevin D.; McLaughlin, John P.; Gruner, Daniel S.; Bogar, Taylor A.; Bui, An; Childress, Jasmine N.; Espinoza, Magaly; Forbes, Elizabeth S.; Johnston, Cora A.; Klope, Maggie; Kuile, Ana Miller-ter; Lee, Michelle; Plummer, Katherine A.; Weber, David A.; Young, Ronald T.; Young, Hillary S.

2018-01-01

The Asian tiger mosquito, Aedes albopictus, appears to have been extirpated from Palmyra Atoll following rat eradication. Anecdotal biting reports, collection records, and regular captures in black-light traps showed the species was present before rat eradication. Since then, there have been no biting reports and no captures over 2 years of extensive trapping (black-light and scent traps). By contrast, the southern house mosquito, Culex quinquefasciatus, was abundant before and after rat eradication. We hypothesize that mammals were a substantial and preferred blood meal for Aedes, whereas Culex feeds mostly on seabirds. Therefore, after rat eradication, humans and seabirds alone could not support positive population growth or maintenance of Aedes. This seems to be the first documented accidental secondary extinction of a mosquito. Furthermore, it suggests that preferred host abundance can limit mosquito populations, opening new directions for controlling important disease vectors that depend on introduced species like rats.

Population control of the malaria vector Anopheles pseudopunctipennis by habitat manipulation.

PubMed Central

Bond, J. Guillermo; Rojas, Julio C.; Arredondo-Jiménez, Juan I.; Quiroz-Martínez, Humberto; Valle, Javier; Williams, Trevor

2004-01-01

Insect vector-borne diseases continue to present a major challenge to human health. Understanding the factors that regulate the size of mosquito populations is considered fundamental to the ability to predict disease transmission rates and for vector population control. The mosquito, Anopheles pseudopunctipennis, a vector of Plasmodium spp., breeds in riverside pools containing filamentous algae in Mesoamerica. Breeding pools along 3 km sections of the River Coatan, Chiapas, Mexico were subjected to algal extraction or left as controls in a cross-over trial extending over 2 years. Initial densities of An. pseudopunctipennis larvae were directly proportional to the prevalence of filamentous algae in each breeding site. The extraction of algae brought about a striking decline in the density of An. pseudopunctipennis larvae sustained for about six weeks, and a concurrent reduction in the adult population in both years of the study. Mark-release experiments indicated that dispersal from adjacent untreated areas was unlikely to exert an important influence on the magnitude of mosquito control that we observed. Habitat manipulation by extraction of filamentous algae offers a unique opportunity for sustainable control of this malaria vector. This technique may represent a valuable intervention, complimenting insecticide spraying of households, to minimize Plasmodium transmission rates in Mesoamerica. PMID:15475337

MAN, MOSQUITOES AND MICROBES.

ERIC Educational Resources Information Center

SCHOONOVER, ROBERT A.

THE CONTROL OF MOSQUITOES IS A MATTER OF INCREASING CONCERN IN THE STATE OF FLORIDA. A BRIEF DESCRIPTION OF THE LIFE CYCLE, VARIOUS SPECIES, CONTROL, AND DESCRIPTION OF DISEASES TRANSMITTED BY THE MOSQUITO WAS PRESENTED. THE ARTICLE CONCLUDED THAT MOSQUITO CONTROL IS NOT ONLY A HEALTH PROBLEM, BUT ALSO A MATTER OF IMPROVED ECONOMICS IN RELATION TO…

A small scale field trial with expanded polystyrene beads for mosquito control in septic tanks.

PubMed

Chang, M S; Lian, S; Jute, N

1995-01-01

A field trial of the use of expanded polystyrene beads (EPSB) to control the breeding of mosquito larvae in household septic tanks was conducted in Sarawak. One week after treatment, the breeding of Culex quinquefasciatus and Aedes albopictus was reduced by 100% and 68.7% respectively. For both species combined, a 57.25% reduction in the adult emergence rate was achieved. No adult was caught in the emergence trap one month after treatment. A reduction in mosquito biting rates was reported by 87.3% of respondents. All households regarded the EPSB treatment as effective. This study has reduced the relatively high infestation rate of A. albopictus in the septic tanks to 16-20%. The EPSB treatment is feasible and practical. Post-treatment assessment using adult emergence traps and the implications for the vector control programme of the local authority are discussed.

The potential for flower nectar to allow mosquito to mosquito transmission of Francisella tularensis

PubMed Central

Payne, Jessica; Gaughenbaugh, Anna; Renshaw, Andrea; Wright, Jenna; Seeber, Roger; Barnes, Rebecca; Florjanczyk, Aleksandr; Horzempa, Joseph

2017-01-01

Francisella tularensis is disseminated in nature by biting arthropods such as mosquitoes. The relationship between mosquitoes and F. tularensis in nature is highly ambiguous, due in part to the fact that mosquitoes have caused significant tularemia outbreaks despite being classified as a mechanical vector of F. tularensis. One possible explanation for mosquitoes being a prominent, yet mechanical vector is that these insects feed on flower nectar between blood meals, allowing for transmission of F. tularensis between mosquitoes. Here, we aimed to assess whether F. tularensis could survive in flower nectar. Moreover, we examined if mosquitoes could interact with or ingest and transmit F. tularensis from one source of nectar to another. F. tularensis exhibited robust survivability in flower nectar with concentrations of viable bacteria remaining consistent with the rich growth medium. Furthermore, F. tularensis was able to survive (albeit to a lesser extent) in 30% sucrose (a nectar surrogate) over a period of time consistent with that of a typical flower bloom. Although we observed diminished bacterial survival in the nectar surrogate, mosquitoes that fed on this material became colonized with F. tularensis. Finally, colonized mosquitoes were capable of transferring F. tularensis to a sterile nectar surrogate. These data suggest that flower nectar may be capable of serving as a temporary source of F. tularensis that could contribute to the amplification of outbreaks. Mosquitoes that feed on an infected mammalian host and subsequently feed on flower nectar could deposit some F. tularensis bacteria into the nectar in the process. Mosquitoes subsequently feeding on this nectar source could potentially become colonized by F. tularensis. Thus, the possibility exists that flower nectar may allow for vector-vector transmission of F. tularensis. PMID:28486521

Tips to Prevent Mosquito Bites

MedlinePlus

... mosquitoes using insecticides. Use Structural Barriers Cover all gaps in walls, doors, and windows to prevent mosquitoes ... into pants and pants into socks to cover gaps in your clothing where mosquitoes can get to ...

The Eye of the Tiger, the Thrill of the Fight: Effective Larval and Adult Control Measures Against the Asian Tiger Mosquito, Aedes albopictus (Diptera: Culicidae), in North America.

PubMed

Faraji, Ary; Unlu, Isik

2016-09-01

The Asian tiger mosquito, Aedes albopictus (Skuse), is a highly invasive container-inhabiting species with a global distribution. This mosquito, similar to other Stegomyia species such as Aedes aegypti (L.), is highly adapted to urban and suburban areas, and commonly oviposits in artificial containers, which are ubiquitous in these peridomestic environments. The increase in speed and amount of international travel and commerce, coupled with global climate change, have aided in the resurgence and expansion of Stegomyia species into new areas of North America. In many parts of their range, both species are implicated as significant vectors of emerging and re-emerging arboviruses such as dengue, chikungunya, and now Zika. Although rapid and major advances have been made in the field of biology, ecology, genetics, taxonomy, and virology, relatively little has changed in the field of mosquito control in recent decades. This is particularly discouraging in regards to container-inhabiting mosquitoes, because traditional integrated mosquito management (IMM) approaches have not been effective against these species. Many mosquito control programs simply do not possess the man-power or necessary financial resources needed to suppress Ae. albopictus effectively. Therefore, control of mosquito larvae, which is the foundation of IMM approaches, is exceptionally difficult over large areas. This review paper addresses larval habitats, use of geographic information systems for habitat preference detection, door-to-door control efforts, source reduction, direct application of larvicides, biological control agents, area-wide low-volume application of larvicides, hot spot treatments, autodissemination stations, public education, adult traps, attractive-toxic sugar bait methods, lethal ovitraps, barrier-residual adulticides, hand-held ultra-low-volume adulticides, area-wide adulticides applied by ground or air, and genetic control methods. The review concludes with future

Mosquito larval productivity in rice-fields infested with Azolla in Mvomero District, Tanzania.

PubMed

Mwingira, V S; Mayala, B K; Senkoro, K P; Rumisha, S F; Shayo, E H; Mlozi, M R S; Mboera, L E G

2009-01-01

Azolla (Salviniales: Azollaceae) is known to reduce oviposition and adult emergence of a number of mosquito species. Several species of Azolla are reportedly indigenous to Tanzania. However, the potential of Azolla as a biocontrol agent against malaria mosquitoes has not been evaluated in the country. This cross-sectional study was carried out to assess mosquito larval productivity in irrigated rice-fields infested with Azolla in Mvomero District, Tanzania. A systematic larval sampling covering all open water bodies along designed transect was carried in rice-fields. Larval density was estimated by dipping water bodies with or without Azolla. The degree of Azolla coverage was categorized as 0%, <50%, 50%, and >80%. Larvae densities were categorised as low (<50/m2), medium (50-500/m2) and high (> or = 500/m2) productivity. A total of 120 water bodies were surveyed and 105 (87.5%) had Azolla microphyla and A. pinnata at varying degrees of coverage. Of the total 105 water bodies with Azolla, 80 (76.2%) had a green Azolla mat, and 25 (23.8%) a brown Azolla mat. Eighty-eight (73.3%) of the sites were infested with anophelines and 109 (90.8%) with culicine larvae. Seventy percent of all water bodies contained anophelines and culicines in sympatric breeding, while 20.8% and 3.3% had only culicines and anophelines, respectively. The majority (82%) of mosquito breeding sites were found in area with Azolla substrate. Mosquito larva productivity was low in sites with highest (>80%) Azolla coverage. Seventy-two (81.8%) of the anopheline and 90 (82.6%) culicine breeding sites were infested with Azolla. Water bodies infested with green Azolla were more productive than those covered by brown coloured Azolla substrates for both culicines (13%) and anophelines (8%). Of the 1537 field collected larvae that hatched to adult stage, 646 (42.03%) were Anopheles gambiae s.l., 42 (2.73%) were An. funestus and 769 (50.03%) were Culex quinquefasciatus. These findings suggest that the

Chikungunya Virus Infection of Aedes Mosquitoes.

PubMed

Wong, Hui Vern; Chan, Yoke Fun; Sam, I-Ching; Sulaiman, Wan Yusof Wan; Vythilingam, Indra

2016-01-01

In vivo infection of mosquitoes is an important method to study and characterize arthropod-borne viruses. Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that is transmitted primarily by Aedes mosquitoes. In this chapter, we describe a protocol for infection of CHIKV in two species of Aedes mosquitoes, Aedes aegypti and Aedes albopictus, together with the isolation of CHIKV in different parts of the infected mosquito such as midgut, legs, wings, salivary gland, head, and saliva. This allows the study of viral infection, replication and dissemination within the mosquito vector.

Expression of the cytochrome P450s, CYP6P3 and CYP6M2 are significantly elevated in multiple pyrethroid resistant populations of Anopheles gambiae s.s. from Southern Benin and Nigeria

PubMed Central

Djouaka, Rousseau F; Bakare, Adekunle A; Coulibaly, Ousmane N; Akogbeto, Martin C; Ranson, Hilary; Hemingway, Janet; Strode, Clare

2008-01-01

Background Insecticide resistance in Anopheles mosquitoes is threatening the success of malaria control programmes. This is particularly true in Benin where pyrethroid resistance has been linked to the failure of insecticide treated bed nets. The role of mutations in the insecticide target sites in conferring resistance has been clearly established. In this study, the contribution of other potential resistance mechanisms was investigated in Anopheles gambiae s.s. from a number of localities in Southern Benin and Nigeria. The mosquitoes were sampled from a variety of breeding sites in a preliminary attempt to investigate the role of contamination of mosquito breeding sites in selecting for resistance in adult mosquitoes. Results All mosquitoes sampled belonged to the M form of An. gambiae s.s. There were high levels of permethrin resistance in an agricultural area (Akron) and an urban area (Gbedjromede), low levels of resistance in mosquito samples from an oil contaminated site (Ojoo) and complete susceptibility in the rural Orogun location. The target site mutation kdrW was detected at high levels in two of the populations (Akron f = 0.86 and Gbedjromede f = 0.84) but was not detected in Ojoo or Orogun. Microarray analysis using the Anopheles gambiae detox chip identified two P450s, CYP6P3 and CYP6M2 up regulated in all three populations, the former was expressed at particularly high levels in the Akron (12.4-fold) and Ojoo (7.4-fold) populations compared to the susceptible population. Additional detoxification and redox genes were also over expressed in one or more populations including two cuticular pre-cursor genes which were elevated in two of the three resistant populations. Conclusion Multiple resistance mechanisms incurred in the different breeding sites contribute to resistance to permethrin in Benin. The cytochrome P450 genes, CYP6P3 and CYP6M2 are upregulated in all three resistant populations analysed. Several additional potential resistance mechanisms

Genomic, Physiologic, and Symbiotic Characterization of Serratia marcescens Strains Isolated from the Mosquito Anopheles stephensi.

PubMed

Chen, Shicheng; Blom, Jochen; Walker, Edward D

2017-01-01

Strains of Serratia marcescens , originally isolated from the gut lumen of adult female Anopheles stephensi mosquitoes, established persistent infection at high rates in adult A. stephensi whether fed to larvae or in the sugar meal to adults. By contrast, the congener S. fonticola originating from Aedes triseriatus had lower infection in A. stephensi , suggesting co-adaptation of Serratia strains in different species of host mosquitoes. Coinfection at high infection rate in adult A. stephensi resulted after feeding S. marcescens and Elizabethkingia anophelis in the sugar meal, but when fed together to larvae, infection rates with E. anophelis were much higher than were S. marcescens in adult A. stephensi , suggesting a suppression effect of coinfection across life stages. A primary isolate of S. marcescens was resistant to all tested antibiotics, showed high survival in the mosquito gut, and produced alpha-hemolysins which contributed to lysis of erythrocytes ingested with the blood meal. Genomes of two primary isolates from A. stephensi , designated S. marcescens ano1 and ano2, were sequenced and compared to other Serratia symbionts associated with insects, nematodes and plants. Serratia marcescens ano1 and ano2 had predicted virulence factors possibly involved in attacking parasites and/or causing opportunistic infection in mosquito hosts. S. marcescens ano1 and ano2 possessed multiple mechanisms for antagonism against other microorganisms, including production of bacteriocins and multi-antibiotic resistance determinants. These genes contributing to potential anti-malaria activity including serralysins, hemolysins and chitinases are only found in some Serratia species. It is interesting that genome sequences in S. marcescens ano1 and ano2 are distinctly different from those in Serratia sp. Ag1 and Ag2 which were isolated from Anopheles gambiae . Compared to Serratia sp. Ag1 and Ag2, S. marcescens ano1 and ano2 have more rRNAs and many important genes involved in

Genomic, Physiologic, and Symbiotic Characterization of Serratia marcescens Strains Isolated from the Mosquito Anopheles stephensi

PubMed Central

Chen, Shicheng; Blom, Jochen; Walker, Edward D.

2017-01-01

Strains of Serratia marcescens, originally isolated from the gut lumen of adult female Anopheles stephensi mosquitoes, established persistent infection at high rates in adult A. stephensi whether fed to larvae or in the sugar meal to adults. By contrast, the congener S. fonticola originating from Aedes triseriatus had lower infection in A. stephensi, suggesting co-adaptation of Serratia strains in different species of host mosquitoes. Coinfection at high infection rate in adult A. stephensi resulted after feeding S. marcescens and Elizabethkingia anophelis in the sugar meal, but when fed together to larvae, infection rates with E. anophelis were much higher than were S. marcescens in adult A. stephensi, suggesting a suppression effect of coinfection across life stages. A primary isolate of S. marcescens was resistant to all tested antibiotics, showed high survival in the mosquito gut, and produced alpha-hemolysins which contributed to lysis of erythrocytes ingested with the blood meal. Genomes of two primary isolates from A. stephensi, designated S. marcescens ano1 and ano2, were sequenced and compared to other Serratia symbionts associated with insects, nematodes and plants. Serratia marcescens ano1 and ano2 had predicted virulence factors possibly involved in attacking parasites and/or causing opportunistic infection in mosquito hosts. S. marcescens ano1 and ano2 possessed multiple mechanisms for antagonism against other microorganisms, including production of bacteriocins and multi-antibiotic resistance determinants. These genes contributing to potential anti-malaria activity including serralysins, hemolysins and chitinases are only found in some Serratia species. It is interesting that genome sequences in S. marcescens ano1 and ano2 are distinctly different from those in Serratia sp. Ag1 and Ag2 which were isolated from Anopheles gambiae. Compared to Serratia sp. Ag1 and Ag2, S. marcescens ano1 and ano2 have more rRNAs and many important genes involved in

Converting Mosquito Surveillance to Arbovirus Surveillance with Honey-Baited Nucleic Acid Preservation Cards.

PubMed

Flies, Emily J; Toi, Cheryl; Weinstein, Philip; Doggett, Stephen L; Williams, Craig R

2015-07-01

Spatially and temporally accurate information about infectious mosquito distribution allows for pre-emptive public health interventions that can reduce the burden of mosquito-borne infections on human populations. However, the labile nature of arboviruses, the low prevalence of infection in mosquitoes, the expensive labor costs for mosquito identification and sorting, and the specialized equipment required for arbovirus testing can obstruct arbovirus surveillance efforts. The recently developed techniques of testing mosquito expectorate using honey-baited nucleic acid preservation cards or sugar bait stations allows a sensitive method of testing for infectious, rather than infected, mosquito vectors. Here we report the results from the first large-scale incorporation of honey-baited cards into an existing mosquito surveillance program. During 4 months of the peak virus season (January-April, 2014) for a total of 577 trap nights, we set CO2-baited encephalitis vector survey (EVS) light traps at 88 locations in South Australia. The collection container for the EVS trap was modified to allow for the placement of a honey-baited nucleic acid preservation card (FTA™ card) inside. After collection, mosquitoes were maintained in a humid environment and allowed access to the cards for 1 week. Cards were then analyzed for common endemic Australian arboviruses using a nested RT-PCR. Eighteen virus detections, including 11 Ross River virus, four Barmah Forest virus, and three Stratford virus (not previously reported from South Australia) were obtained. Our findings suggest that adding FTA cards to an existing mosquito surveillance program is a rapid and efficient way of detecting infectious mosquitoes with high spatial resolution.

Crowdsourcing Science to Promote Human Health: New Tools to Promote Sampling of Mosquito Populations by Citizen Scientists

NASA Astrophysics Data System (ADS)

Boger, R. A.; Low, R.; Jaroensutasinee, M.; Jaroensutasinee, K.; Sparrow, E. B.; Costosa, J. I.; Medina, J.; Randolph, G.

2015-12-01

GLOBE in Thailand and GLOBE in Africa independently developed citizen science protocols for collecting and analyzing mosquito larvae. These protocols have been piloted in several workshops and implemented in schools. Data collected have been used for several secondary, undergraduate and graduate student research studies. Over this past year, 2015, these protocols have been synthesized into one protocol that will be made available to the world-wide community through the GLOBE website (www.globe.gov). This new protocol is designed to be flexible in the mosquito species that can be collected and the types of environments sampled (e.g., containers in and around the house, ponds, irrigation ditches in a rice paddy field). Plans are underway to enable web-based data entry and mobile apps for data collection and submission. Once everything is finalized, a GLOBE field campaign will be initiated for citizen scientists to collect meaningful data on where different types of mosquito larvae are found and how the abundance and distribution is changing seasonally. To assist in the standardization of data collection and quality control, training slides are being developed and will be made available in early 2016. This will enable a wider participation of citizen scientists to participate in this effort to collect mosquito data by making it easier to become part of the GLOBE community. As with mosquito larvae, training slides are being created for hydrosphere, biosphere, atmosphere, and pedosphere GLOBE measurement protocols. The development of the mosquito protocol and the training slides are in direct response to the GLOBE community's desire to increase citizen science participation beyond primary and secondary schools, in observing and measuring environmental change.

Modeling the Response of Anopheles gambiae (Diptera: Culicidae) Populations in the Kenya Highlands to a Rise in Mean Annual Temperature.

PubMed

Wallace, Dorothy; Prosper, Olivia; Savos, Jacob; Dunham, Ann M; Chipman, Jonathan W; Shi, Xun; Ndenga, Bryson; Githeko, Andrew

2017-03-01

A dynamical model of Anopheles gambiae larval and adult populations is constructed that matches temperature-dependent maturation times and mortality measured experimentally as well as larval instar and adult mosquito emergence data from field studies in the Kenya Highlands. Spectral classification of high-resolution satellite imagery is used to estimate household density. Indoor resting densities collected over a period of one year combined with predictions of the dynamical model give estimates of both aquatic habitat and total adult mosquito densities. Temperature and precipitation patterns are derived from monthly records. Precipitation patterns are compared with average and extreme habitat estimates to estimate available aquatic habitat in an annual cycle. These estimates are coupled with the original model to produce estimates of adult and larval populations dependent on changing aquatic carrying capacity for larvae and changing maturation and mortality dependent on temperature. This paper offers a general method for estimating the total area of aquatic habitat in a given region, based on larval counts, emergence rates, indoor resting density data, and number of households.Altering the average daily temperature and the average daily rainfall simulates the effect of climate change on annual cycles of prevalence of An. gambiae adults. We show that small increases in average annual temperature have a large impact on adult mosquito density, whether measured at model equilibrium values for a single square meter of habitat or tracked over the course of a year of varying habitat availability and temperature. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The Citizen Science Project 'Mueckenatlas' Helps Monitor the Distribution and Spread of Invasive Mosquito Species in Germany.

PubMed

Walther, Doreen; Kampen, Helge

2017-11-07

The citizen science project 'Mueckenatlas' (mosquito atlas) was implemented in early 2012 to improve mosquito surveillance in Germany. Citizens are asked to support the spatiotemporal mapping of culicids by submitting mosquito specimens collected in their private surroundings. The Mueckenatlas has developed into an efficient tool for data collection with close to 30,000 mosquitoes submitted by the end of 2015. While the vast majority of submissions included native mosquito species, a small percentage represented invasive species. The discovery of Aedes albopictus (Skuse) (Diptera: Culicidae), Aedes japonicus japonicus (Theobald) (Diptera: Culicidae) and Aedes koreicus (Edwards) (Diptera: Culicidae) specimens via the Mueckenatlas project prompted targeted monitoring activities in the field which produced additional information on the distribution of these species in Germany. Among others, Mueckenatlas submissions led to the detection of three populations of Ae. j. japonicus in West, North and Southeast Germany in 2012, 2013, and 2015, respectively. As demonstrated by on-site monitoring, the origins of Ae. j. japonicus specimens submitted to the Mueckenatlas mirror the distribution areas of the four presently known German populations as found by active field sampling (the fourth population already reported prior to the launch of the Mueckenatlas). The data suggest that a citizen science project such as the Mueckenatlas may aid in detecting changes in the mosquito fauna and can therefore be used to guide the design of more targeted field surveillance activities. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

Importance of eaves to house entry by anopheline, but not culicine, mosquitoes.

PubMed

Njie, Mbye; Dilger, Erin; Lindsay, Steven W; Kirby, Matthew J

2009-05-01

Screening homes is an effective way of reducing house entry by mosquitoes. Here, we assess how important blocking the eaves is for reducing house entry by anopheline and culicine mosquitoes for houses that have screened doors and no windows. Twelve houses, with two screened doors and no windows, in which a single adult male slept, were included in a simple crossover design. In the first period, six houses were randomly selected and had the eaves blocked using a mixture of rubble and mortar; the other six were left with open eaves. Mosquitoes were sampled using CDC light traps from each house twice a week for 4 wk. Mosquito control activities and the number and type of domestic animals within the compound was recorded on each sampling occasion. Before beginning the second sampling period, homes with blocked eaves had them opened, and those with open eaves had them closed. Mosquitoes were then sampled from each house for a further 4 wk. When houses had their eaves closed, a three-fold reduction in Anopheles gambiae s.l. Giles caught indoors was observed. However, there was no reduction in total culicine numbers observed. This study demonstrates that the eaves are the major route by which An. gambiae enters houses. By contrast, culicine mosquitoes enter largely through doors and windows. Sealing the eave gap is an important method for reducing malaria transmission in homes where doors and windows are screened.

Antipathogen genes and the replacement of disease-vectoring mosquito populations: a model-based evaluation

PubMed Central

Robert, Michael A; Okamoto, Kenichi W; Gould, Fred; Lloyd, Alun L

2014-01-01

Recently, genetic strategies aimed at controlling populations of disease-vectoring mosquitoes have received considerable attention as alternatives to traditional measures. Theoretical studies have shown that female-killing (FK), antipathogen (AP), and reduce and replace (R&R) strategies can each decrease the number competent vectors. In this study, we utilize a mathematical model to evaluate impacts on competent Aedes aegypti populations of FK, AP, and R&R releases as well as hybrid strategies that result from combinations of these three approaches. We show that while the ordering of efficacy of these strategies depends upon population life history parameters, sex ratio of releases, and switch time in combination strategies, AP-only and R&R/AP releases typically lead to the greatest long-term reduction in competent vectors. R&R-only releases are often less effective at long-term reduction of competent vectors than AP-only releases or R&R/AP releases. Furthermore, the reduction in competent vectors caused by AP-only releases is easier to maintain than that caused by FK-only or R&R-only releases even when the AP gene confers a fitness cost. We discuss the roles that density dependence and inclusion of females play in the order of efficacy of the strategies. We anticipate that our results will provide added impetus to continue developing AP strategies. PMID:25558284

Anopheline and culicine mosquitoes are not repelled by surfaces treated with the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana

PubMed Central

2010-01-01

Background Entomopathogenic fungi, Metarhizium anisopliae and Beauveria bassiana, are promising bio-pesticides for application against adult malaria mosquito vectors. An understanding of the behavioural responses of mosquitoes towards these fungi is necessary to guide development of fungi beyond the 'proof of concept' stage and to design suitable intervention tools. Methods Here we tested whether oil-formulations of the two fungi could be detected and avoided by adult Anopheles gambiae s.s., Anopheles arabiensis and Culex quinquefasciatus. The bioassays used a glass chamber divided into three compartments (each 250 × 250 × 250 mm): release, middle and stimulus compartments. Netting with or without fungus was fitted in front of the stimulus compartment. Mosquitoes were released and the proportion that entered the stimulus compartment was determined and compared between treatments. Treatments were untreated netting (control 1), netting with mineral oil (control 2) and fungal conidia formulated in mineral oil evaluated at three different dosages (2 × 1010, 4 × 1010 and 8 × 1010 conidia m-2). Results Neither fungal strain was repellent as the mean proportion of mosquitoes collected in the stimulus compartment did not differ between experiments with surfaces treated with and without fungus regardless of the fungal isolate and mosquito species tested. Conclusion Our results indicate that mineral-oil formulations of M. anisopliae and B. bassiana were not repellent against the mosquito species tested. Therefore, both fungi are suitable candidates for the further development of tools that aim to control host-seeking or resting mosquitoes using entomopathogenic fungi. PMID:20799937

Lessons from mosquitoes' painless piercing.

PubMed

Gurera, Dev; Bhushan, Bharat; Kumar, Navin

2018-05-18

Arthropods are the largest group of the living organisms. They attack other organisms by biting, stinging, or piercing and sucking. Among various medically important arthropods, which feed on living hosts, mosquitoes' piercing spread viruses which have been reported to cause the highest number of deaths annually. The primary cause of the deaths is malaria, which is spread by infected mosquitoes' piercing. This study aims at elucidating lessons from mosquitoes' painless piercing. Mosquitoes pierce using their fascicle, which is a bundle of coherently functioning six stylets. Based on experiments and available literature, it is presented that mosquitoes painlessly pierce using a combination of the numbing, the fascicle's serrated design, the vibratory actuation, and the graded and frequency-dependent mechanical properties of the labrum. Based on this understanding, a mosquito-inspired microneedle design has also been proposed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Mosquito distribution in a saltmarsh: determinants of eggs in a variable environment.

PubMed

Rowbottom, Raylea; Carver, Scott; Barmuta, Leon A; Weinstein, Philip; Allen, Geoff R

2017-06-01

Two saltmarsh mosquitoes dominate the transmission of Ross River virus (RRV, Togoviridae: Alphavirus), one of Australia's most prominent mosquito-borne diseases. Ecologically, saltmarshes vary in their structure, including habitat types, hydrological regimes, and diversity of aquatic fauna, all of which drive mosquito oviposition behavior. Understanding the distribution of vector mosquitoes within saltmarshes can inform early warning systems, surveillance, and management of vector populations. The aim of this study was to identify the distribution of Ae. camptorhynchus, a known vector for RRV, across a saltmarsh and investigate the influence that other invertebrate assemblage might have on Ae. camptorhynchus egg dispersal. We demonstrate that vegetation is a strong indicator for Ae. camptorhynchus egg distribution, and this was not correlated with elevation or other invertebrates located at this saltmarsh. Also, habitats within this marsh are less frequently inundated, resulting in dryer conditions. We conclude that this information can be applied in vector surveillance and monitoring of temperate saltmarsh environments and also provides a baseline for future investigations into understanding mosquito vector habitat requirements. © 2017 The Society for Vector Ecology.

Colonization of UK coastal realignment sites by mosquitoes: implications for design, management, and public health.

PubMed

Medlock, J M; Vaux, A G C

2013-06-01

Coastal realignment is now widely instituted in the UK as part of local flood risk management plans to compensate for the loss of European protected habitat and to mitigate the effects of sea-level rise and coastal squeeze. Coastal aquatic habitats have long been known to provide suitable habitats for brackish-water mosquitoes and historically, coastal marshes were considered to support anopheline mosquito populations that were responsible for local malaria transmission. This study surveyed the eight largest managed realignment (MRA) sites in England (Essex and the Humber) for mosquito habitats. The apparent absence of anopheline mosquitoes exploiting aquatic habitats at all of these sites suggests that the risk of malaria associated with MRA sites is currently negligible. However, three of the eight sites supported populations of two nuisance and potential arboviral vector species, Aedes detritus and Aedes caspius. The aquatic habitats that supported mosquitoes resulted from a) specific design aspects of the new sea wall (ballast to mitigate wave action and constructed saline borrow ditches) that could be designed out or managed or b) isolated pools created through silt accretion or expansion of flooded zones to neighbouring pasture. The public health risks and recommendations for management are discussed in this report. This report highlights the need for pro-active public health impact assessments prior to MRA development in consultation with the Health Protection Agency, as well as the need for a case-by-case approach to design and management to mitigate mosquito or mosquito-borne disease issues now and in the future. © 2013 The Society for Vector Ecology.

Optical remote sensing for monitoring flying mosquitoes, gender identification and discussion on species identification

NASA Astrophysics Data System (ADS)

Genoud, Adrien P.; Basistyy, Roman; Williams, Gregory M.; Thomas, Benjamin P.

2018-03-01

Mosquito-borne diseases are a major challenge for Human health as they affect nearly 700 million people every year and result in over 1 million deaths. Reliable information on the evolution of population and spatial distribution of key insects species is of major importance in the development of eco-epidemiologic models. This paper reports on the remote characterization of flying mosquitoes using a continuous-wave infrared optical remote sensing system. The system is setup in a controlled environment to mimic long-range lidars, mosquitoes are free flying at a distance of 4 m from the collecting optics. The wing beat frequency is retrieved from the backscattered light from mosquitoes transiting through the laser beam. A total of 427 transit signals have been recorded from three mosquito species, males and females. Since the mosquito species and gender are known a priori, we investigate the use of wing beat frequency as the sole predictor variable for two Bayesian classifications: gender alone (two classes) and species/gender (six classes). The gender of each mosquito is retrieved with a 96.5% accuracy while the species/gender of mosquitoes is retrieved with a 62.3% accuracy. Known to be an efficient mean to identify insect family, we discuss the limitations of using wing beat frequency alone to identify insect species.

Harnessing mosquito-Wolbachia symbiosis for vector and disease control.

PubMed

Bourtzis, Kostas; Dobson, Stephen L; Xi, Zhiyong; Rasgon, Jason L; Calvitti, Maurizio; Moreira, Luciano A; Bossin, Hervé C; Moretti, Riccardo; Baton, Luke Anthony; Hughes, Grant L; Mavingui, Patrick; Gilles, Jeremie R L

2014-04-01

Mosquito species, members of the genera Aedes, Anopheles and Culex, are the major vectors of human pathogens including protozoa (Plasmodium sp.), filariae and of a variety of viruses (causing dengue, chikungunya, yellow fever, West Nile). There is lack of efficient methods and tools to treat many of the diseases caused by these major human pathogens, since no efficient vaccines or drugs are available; even in malaria where insecticide use and drug therapies have reduced incidence, 219 million cases still occurred in 2010. Therefore efforts are currently focused on the control of vector populations. Insecticides alone are insufficient to control mosquito populations since reduced susceptibility and even resistance is being observed more and more frequently. There is also increased concern about the toxic effects of insecticides on non-target (even beneficial) insect populations, on humans and the environment. During recent years, the role of symbionts in the biology, ecology and evolution of insect species has been well-documented and has led to suggestions that they could potentially be used as tools to control pests and therefore diseases. Wolbachia is perhaps the most renowned insect symbiont, mainly due to its ability to manipulate insect reproduction and to interfere with major human pathogens thus providing new avenues for pest control. We herein present recent achievements in the field of mosquito-Wolbachia symbiosis with an emphasis on Aedes albopictus. We also discuss how Wolbachia symbiosis can be harnessed for vector control as well as the potential to combine the sterile insect technique and Wolbachia-based approaches for the enhancement of population suppression programs. Copyright © 2013 International Atomic Energy Agency 2013. Published by Elsevier B.V. All rights reserved.

Assessing quality of life-shortening Wolbachia-infected Aedes aegypti mosquitoes in the field based on capture rates and morphometric assessments

PubMed Central

2014-01-01

Background Recent releases have been carried out with Aedes aegypti mosquitoes infected with the wMelPop mosquito cell-line adapted (wMelPop-CLA) strain of Wolbachia. This infection introduced from Drosophila provides strong blockage of dengue and other arboviruses but also has large fitness costs in laboratory tests. The releases were used to evaluate the fitness of released infected mosquitoes, and (following termination of releases) to test for any effects of wMelPop-CLA on wing size and shape when mosquitoes were reared under field conditions. Methods We monitored gravid females via double sticky traps to assess the reproductive success of wMelPop-CLA-infected females and also sampled the overall mosquito population post-release using Biogent Sentinel traps. Morphometric analyses were used to evaluate infection effects on wing shape as well as size. Results Oviposition success as assessed through double sticky traps was unrelated to size of released mosquitoes. However, released mosquitoes with lower wing loading were more successful. Furthermore, wMelPop-CLA-infected mosquitoes had 38.3% of the oviposition success of uninfected mosquitoes based on the predicted infection frequency after release. Environmental conditions affected wing shape and particularly size across time in uninfected mosquitoes, but not in naturally-reared wMelPop-CLA-infected mosquitoes. Although the overall size and shape do not differ between naturally-reared wMelPop-CLA-infected and uninfected mosquitoes, the infected mosquitoes tended to have smaller wings than uninfected mosquitoes during the cooler November in comparison to December. Conclusion These results confirm the lower fitness of wMelPop-CLA infection under field conditions, helping to explain challenges associated with a successful invasion by this strain. In the long run, invasion may depend on releasing strains carrying insecticide resistance or egg desiccation resistance, combined with an active pre-release population

Evaluating the Vector Control Potential of the In2Care® Mosquito Trap Against Aedes aegypti and Aedes albopictus Under Semifield Conditions in Manatee County, Florida.

PubMed

Buckner, Eva A; Williams, Katie F; Marsicano, Ambyr L; Latham, Mark D; Lesser, Christopher R

2017-09-01

Successful integrated vector management programs may need new strategies in addition to conventional larviciding and adulticiding strategies to target Aedes aegypti and Ae. albopictus, which can develop in small, often cryptic, artificial and natural containers. The In2Care® mosquito trap was recently developed to target and kill larval and adult stages of these invasive container-inhabiting Aedes mosquitoes by utilizing autodissemination. Gravid females that visit the trap pick up pyriproxyfen (PPF) that they later transfer to nearby larval habitats as well as Beauveria bassiana spores that slowly kill them. We assessed the efficacy of the In2Care mosquito trap in a semifield setting against locally sourced strains of Ae. aegypti and Ae. albopictus. We found that the In2Care mosquito trap is attractive to gravid Ae. aegypti and Ae. albopictus females and serves as an egg sink, preventing any adult emergence from the trap (P = 0.0053 for both species). Adult females successfully autodisseminated PPF to surrounding water-filled containers, leading to a statistically significant reduction in new mosquito emergence (P ≤ 0.0002 for both species). Additionally, we found effective contamination with Beauveria bassiana spores, which significantly reduced the survivorship of exposed Ae. aegypti and Ae. albopictus (P ≤ 0.008 for both species in all experimental setups). In summary, the In2Care mosquito trap successfully killed multiple life stages of 2 main mosquito vector species found in Florida under semifield conditions.