Vision-Based Perception and Classification of Mosquitoes Using Support Vector Machine

Directory of Open Access Journals (Sweden)

Masataka Fuchida

2017-01-01

Full Text Available The need for a novel automated mosquito perception and classification method is becoming increasingly essential in recent years, with steeply increasing number of mosquito-borne diseases and associated casualties. There exist remote sensing and GIS-based methods for mapping potential mosquito inhabitants and locations that are prone to mosquito-borne diseases, but these methods generally do not account for species-wise identification of mosquitoes in closed-perimeter regions. Traditional methods for mosquito classification involve highly manual processes requiring tedious sample collection and supervised laboratory analysis. In this research work, we present the design and experimental validation of an automated vision-based mosquito classification module that can deploy in closed-perimeter mosquito inhabitants. The module is capable of identifying mosquitoes from other bugs such as bees and flies by extracting the morphological features, followed by support vector machine-based classification. In addition, this paper presents the results of three variants of support vector machine classifier in the context of mosquito classification problem. This vision-based approach to the mosquito classification problem presents an efficient alternative to the conventional methods for mosquito surveillance, mapping and sample image collection. Experimental results involving classification between mosquitoes and a predefined set of other bugs using multiple classification strategies demonstrate the efficacy and validity of the proposed approach with a maximum recall of 98%.

Biological Control of Mosquito Vectors: Past, Present, and Future

Directory of Open Access Journals (Sweden)

Giovanni Benelli

2016-10-01

Full Text Available Mosquitoes represent the major arthropod vectors of human disease worldwide transmitting malaria, lymphatic filariasis, and arboviruses such as dengue virus and Zika virus. Unfortunately, no treatment (in the form of vaccines or drugs is available for most of these diseases andvectorcontrolisstillthemainformofprevention. Thelimitationsoftraditionalinsecticide-based strategies, particularly the development of insecticide resistance, have resulted in significant efforts to develop alternative eco-friendly methods. Biocontrol strategies aim to be sustainable and target a range of different mosquito species to reduce the current reliance on insecticide-based mosquito control. In thisreview, weoutline non-insecticide basedstrategiesthat havebeenimplemented orare currently being tested. We also highlight the use of mosquito behavioural knowledge that can be exploited for control strategies.

Does mosquito control have an effect on mosquito-borne disease? The case of Ross River virus disease and mosquito management in Queensland, Australia.

Science.gov (United States)

Tomerini, Deanna M; Dale, Pat E; Sipe, Neil

2011-03-01

We examined the relationship between types of mosquito control programs and the mosquito-borne Ross River virus (RRV) disease in Queensland, Australia. Mosquito control information was collected through a survey of the responsible agencies (local governments), and RRV disease notification data were provided by the Queensland state health authority. The study developed a typology of mosquito control programs, based on the approaches used. Based on the analysis of data on RRV disease rates between mosquito control types within 4 climatic regions, each region had different combinations of mosquito control strategies in their programs; there were also general similarities in the relationship between program types and RRV rates between the regions. The long-term RRV disease rates were lower in areas where the mosquito control program included pre-emptive (rather than reactive) surveillance based on an extensive (rather than incomplete) knowledge of mosquito habitats, and where treatment of both saltwater and freshwater habitats (compared to only saltwater habitats, in coastal areas) occurred. The data indicate that mosquito control is an effective public health intervention to reduce mosquito-borne disease; hence, climate change adaptation strategies should ensure that adequate resources are available for effective vector control so as to manage the risk of mosquito-borne diseases.

Vector competence of Anopheles and Culex mosquitoes for Zika virus

Directory of Open Access Journals (Sweden)

Brittany L. Dodson

2017-03-01

Full Text Available Zika virus is a newly emergent mosquito-borne flavivirus that has caused recent large outbreaks in the new world, leading to dramatic increases in serious disease pathology including Guillain-Barre syndrome, newborn microcephaly, and infant brain damage. Although Aedes mosquitoes are thought to be the primary mosquito species driving infection, the virus has been isolated from dozens of mosquito species, including Culex and Anopheles species, and we lack a thorough understanding of which mosquito species to target for vector control. We exposed Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes to blood meals supplemented with two Zika virus strains. Mosquito bodies, legs, and saliva were collected five, seven, and 14 days post blood meal and tested for infectious virus by plaque assay. Regardless of titer, virus strain, or timepoint, Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes were refractory to Zika virus infection. We conclude that Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus mosquitoes likely do not contribute significantly to Zika virus transmission to humans. However, future studies should continue to explore the potential for other novel potential vectors to transmit the virus.

Biological Control Strategies for Mosquito Vectors of Arboviruses.

Science.gov (United States)

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.

Vector competence of Aedes aegypti mosquitoes for filarial nematodes is affected by age and nutrient limitation.

Science.gov (United States)

Ariani, Cristina V; Juneja, Punita; Smith, Sophia; Tinsley, Matthew C; Jiggins, Francis M

2015-01-01

Mosquitoes are one of the most important vectors of human disease. The ability of mosquitoes to transmit disease is dependent on the age structure of the population, as mosquitoes must survive long enough for the parasites to complete their development and infect another human. Age could have additional effects due to mortality rates and vector competence changing as mosquitoes senesce, but these are comparatively poorly understood. We have investigated these factors using the mosquito Aedes aegypti and the filarial nematode Brugia malayi. Rather than observing any effects of immune senescence, we found that older mosquitoes were more resistant, but this only occurred if they had previously been maintained on a nutrient-poor diet of fructose. Constant blood feeding reversed this decline in vector competence, meaning that the number of parasites remained relatively unchanged as mosquitoes aged. Old females that had been maintained on fructose also experienced a sharp spike in mortality after an infected blood meal ("refeeding syndrome") and few survived long enough for the parasite to develop. Again, this effect was prevented by frequent blood meals. Our results indicate that old mosquitoes may be inefficient vectors due to low vector competence and high mortality, but that frequent blood meals can prevent these effects of age. Copyright © 2014 Elsevier Inc. All rights reserved.

Biological Control Strategies for Mosquito Vectors of Arboviruses

Directory of Open Access Journals (Sweden)

Yan-Jang S. Huang

2017-02-01

Full Text Available 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.

Comparative genomic analysis of Drosophila melanogaster and vector mosquito developmental genes.

Directory of Open Access Journals (Sweden)

Susanta K Behura

Full Text Available Genome sequencing projects have presented the opportunity for analysis of developmental genes in three vector mosquito species: Aedes aegypti, Culex quinquefasciatus, and Anopheles gambiae. A comparative genomic analysis of developmental genes in Drosophila melanogaster and these three important vectors of human disease was performed in this investigation. While the study was comprehensive, special emphasis centered on genes that 1 are components of developmental signaling pathways, 2 regulate fundamental developmental processes, 3 are critical for the development of tissues of vector importance, 4 function in developmental processes known to have diverged within insects, and 5 encode microRNAs (miRNAs that regulate developmental transcripts in Drosophila. While most fruit fly developmental genes are conserved in the three vector mosquito species, several genes known to be critical for Drosophila development were not identified in one or more mosquito genomes. In other cases, mosquito lineage-specific gene gains with respect to D. melanogaster were noted. Sequence analyses also revealed that numerous repetitive sequences are a common structural feature of Drosophila and mosquito developmental genes. Finally, analysis of predicted miRNA binding sites in fruit fly and mosquito developmental genes suggests that the repertoire of developmental genes targeted by miRNAs is species-specific. The results of this study provide insight into the evolution of developmental genes and processes in dipterans and other arthropods, serve as a resource for those pursuing analysis of mosquito development, and will promote the design and refinement of functional analysis experiments.

A generic model for a single strain mosquito-transmitted disease with memory on the host and the vector.

Science.gov (United States)

Sardar, Tridip; Rana, Sourav; Bhattacharya, Sabyasachi; Al-Khaled, Kamel; Chattopadhyay, Joydev

2015-05-01

In the present investigation, three mathematical models on a common single strain mosquito-transmitted diseases are considered. The first one is based on ordinary differential equations, and other two models are based on fractional order differential equations. The proposed models are validated using published monthly dengue incidence data from two provinces of Venezuela during the period 1999-2002. We estimate several parameters of these models like the order of the fractional derivatives (in case of two fractional order systems), the biting rate of mosquito, two probabilities of infection, mosquito recruitment and mortality rates, etc., from the data. The basic reproduction number, R0, for the ODE system is estimated using the data. For two fractional order systems, an upper bound for, R0, is derived and its value is obtained using the published data. The force of infection, and the effective reproduction number, R(t), for the three models are estimated using the data. Sensitivity analysis of the mosquito memory parameter with some important responses is worked out. We use Akaike Information Criterion (AIC) to identify the best model among the three proposed models. It is observed that the model with memory in both the host, and the vector population provides a better agreement with epidemic data. Finally, we provide a control strategy for the vector-borne disease, dengue, using the memory of the host, and the vector. Copyright © 2015 Elsevier Inc. All rights reserved.

Mosquitoes as vectors of human disease in South Africa | Jupp ...

African Journals Online (AJOL)

While malaria is the most important mosquito-borne disease in South Africa, there are also several mosquito-borne viruses that also cause human disease. The most significant are chikungunya, West Nile, Sindbis and Rift Valley fever viruses. In this review these are compared with malaria, mainly in regard to their ecology ...

Mosquitoes and Culicoides biting midges: vector range and the influence of climate change.

Science.gov (United States)

Elbers, A R W; Koenraadt, C J M; Meiswinkel, R

2015-04-01

Vector-borne animal diseases pose a continuous and substantial threat to livestock economies around the globe. Increasing international travel, the globalisation of trade, and climate change are likely to play a progressively more important role in the introduction, establishment and spread of arthropod-borne pathogens worldwide. A review of the literature reveals that many climatic variables, functioning singly or in combination, exert varying effects on the distribution and range of Culicoides vector midges and mosquitoes. For example, higher temperatures may be associated with increased insect abundance--thereby amplifying the risk of disease transmission--but there are no indications yet of dramatic shifts occurring in the geographic range of Culicoides midges. However, the same cannot be said for mosquitoes: over the last few decades, multiple Asian species have established themselves in Europe, spread and are unlikely to ever be eradicated. Research on how insects respond to changes in climate is still in its infancy. The authors argue that we need to grasp how other annectant changes, such as extremes in precipitation (drought and flooding), may affect the dispersal capability of mosquitoes. Models are useful for assessing the interplay between mosquito vectors expanding their range and the native flora and fauna; however, ecological studies employing classical mark-release-recapture techniques remain essential for addressing fundamental questions about the survival and dispersal of mosquito species, with the resulting parameters fed directly into new-generation disease transmission models. Studies on the eventual impact of mosquitoes on animal and human health should be tackled through large-scale integrated research programmes. Such an approach calls for more collaborative efforts, along the lines of the One Health Initiative.

Vector Competence of American Mosquitoes for Three Strains of Zika Virus.

Directory of Open Access Journals (Sweden)

James Weger-Lucarelli

2016-10-01

Full Text Available In 2015, Zika virus (ZIKV; Flaviviridae; Flavivirus emerged in the Americas, causing millions of infections in dozens of countries. The rapid spread of the virus and the association with disease outcomes such as Guillain-Barré syndrome and microcephaly make understanding transmission dynamics essential. Currently, there are no reports of vector competence (VC of American mosquitoes for ZIKV isolates from the Americas. Further, it is not clear whether ZIKV strains from other genetic lineages can be transmitted by American Aedes aegypti populations, and whether the scope of the current epidemic is in part facilitated by viral factors such as enhanced replicative fitness or increased vector competence. Therefore, we characterized replication of three ZIKV strains, one from each of the three phylogenetic clades in several cell lines and assessed their abilities to be transmitted by Ae. aegypti mosquitoes. Additionally, laboratory colonies of different Culex spp. were infected with an American outbreak strain of ZIKV to assess VC. Replication rates were variable and depended on virus strain, cell line and MOI. African strains used in this study outcompeted the American strain in vitro in both mammalian and mosquito cell culture. West and East African strains of ZIKV tested here were more efficiently transmitted by Ae. aegypti from Mexico than was the currently circulating American strain of the Asian lineage. Long-established laboratory colonies of Culex mosquitoes were not efficient ZIKV vectors. These data demonstrate the capacity for additional ZIKV strains to infect and replicate in American Aedes mosquitoes and suggest that neither enhanced virus replicative fitness nor virus adaptation to local vector mosquitoes seems likely to explain the extent and intensity of ZIKV transmission in the Americas.

The effects of climate change and globalization on mosquito vectors: evidence from Jeju Island, South Korea on the potential for Asian tiger mosquito (Aedes albopictus influxes and survival from Vietnam rather than Japan.

Directory of Open Access Journals (Sweden)

Su Hyun Lee

Full Text Available BACKGROUND: Climate change affects the survival and transmission of arthropod vectors as well as the development rates of vector-borne pathogens. Increased international travel is also an important factor in the spread of vector-borne diseases (VBDs such as dengue, West Nile, yellow fever, chikungunya, and malaria. Dengue is the most important vector-borne viral disease. An estimated 2.5 billion people are at risk of infection in the world and there are approximately 50 million dengue infections and an estimated 500,000 individuals are hospitalized with dengue haemorrhagic fever annually. The Asian tiger mosquito (Aedes albopictus is one of the vectors of dengue virus, and populations already exist on Jeju Island, South Korea. Currently, colder winter temperatures kill off Asian tiger mosquito populations and there is no evidence of the mosquitos being vectors for the dengue virus in this location. However, dengue virus-bearing mosquito vectors can inflow to Jeju Island from endemic area such as Vietnam by increased international travel, and this mosquito vector's survival during colder winter months will likely occur due to the effects of climate change. METHODS AND RESULTS: In this section, we show the geographical distribution of medically important mosquito vectors such as Ae. albopictus, a vector of both dengue and chikungunya viruses; Culex pipiens, a vector of West Nile virus; and Anopheles sinensis, a vector of Plasmodium vivax, within Jeju Island, South Korea. We found a significant association between the mean temperature, amount of precipitation, and density of mosquitoes. The phylogenetic analyses show that an Ae. albopictus, collected in southern area of Jeju Island, was identical to specimens found in Ho Chi Minh, Vietnam, and not Nagasaki, Japan. CONCLUSION: Our results suggest that mosquito vectors or virus-bearing vectors can transmit from epidemic regions of Southeast Asia to Jeju Island and can survive during colder winter

Distribution of Brugia malayi larvae and DNA in vector and non-vector mosquitoes: implications for molecular diagnostics

Directory of Open Access Journals (Sweden)

Christensen Bruce M

2009-11-01

Full Text Available Abstract Background The purpose of this study was to extend prior studies of molecular detection of Brugia malayi DNA in vector (Aedes aegypti- Liverpool and non-vector (Culex pipiens mosquitoes at different times after ingestion of infected blood. Results Parasite DNA was detected over a two week time course in 96% of pooled thoraces of vector mosquitoes. In contrast, parasite DNA was detected in only 24% of thorax pools from non-vectors; parasite DNA was detected in 56% of midgut pools and 47% of abdomen pools from non-vectors. Parasite DNA was detected in vectors in the head immediately after the blood meal and after 14 days. Parasite DNA was also detected in feces and excreta of the vector and non-vector mosquitoes which could potentially confound results obtained with field samples. However, co-housing experiments failed to demonstrate transfer of parasite DNA from infected to non-infected mosquitoes. Parasites were also visualized in mosquito tissues by immunohistololgy using an antibody to the recombinant filarial antigen Bm14. Parasite larvae were detected consistently after mf ingestion in Ae. aegypti- Liverpool. Infectious L3s were seen in the head, thorax and abdomen of vector mosquitoes 14 days after Mf ingestion. In contrast, parasites were only detected by histology shortly after the blood meal in Cx. pipiens, and these were not labeled by the antibody. Conclusion This study provides new information on the distribution of filarial parasites and parasite DNA in vector and non-vector mosquitoes. This information should be useful for those involved in designing and interpreting molecular xenomonitoring studies.

Relationship between exposure to vector bites and antibody responses to mosquito salivary gland extracts.

Science.gov (United States)

Fontaine, Albin; Pascual, Aurélie; Orlandi-Pradines, Eve; Diouf, Ibrahima; Remoué, Franck; Pagès, Frédéric; Fusaï, Thierry; Rogier, Christophe; Almeras, Lionel

2011-01-01

Mosquito-borne diseases are major health problems worldwide. Serological responses to mosquito saliva proteins may be useful in estimating individual exposure to bites from mosquitoes transmitting these diseases. However, the relationships between the levels of these IgG responses and mosquito density as well as IgG response specificity at the genus and/or species level need to be clarified prior to develop new immunological markers to assess human/vector contact. To this end, a kinetic study of antibody levels against several mosquito salivary gland extracts from southeastern French individuals living in three areas with distinct ecological environments and, by implication, distinct Aedes caspius mosquito densities were compared using ELISA. A positive association was observed between the average levels of IgG responses against Ae. caspius salivary gland extracts and spatial Ae. caspius densities. Additionally, the average level of IgG responses increased significantly during the peak exposure to Ae. caspius at each site and returned to baseline four months later, suggesting short-lived IgG responses. The species-specificity of IgG antibody responses was determined by testing antibody responses to salivary gland extracts from Cx. pipiens, a mosquito that is present at these three sites at different density levels, and from two other Aedes species not present in the study area (Ae. aegypti and Ae. albopictus). The IgG responses observed against these mosquito salivary gland extracts contrasted with those observed against Ae. caspius salivary gland extracts, supporting the existence of species-specific serological responses. By considering different populations and densities of mosquitoes linked to environmental factors, this study shows, for the first time, that specific IgG antibody responses against Ae. caspius salivary gland extracts may be related to the seasonal and geographical variations in Ae. caspius density. Characterisation of such immunological

The effect of vector control strategy against Dengue transmission between mosquitoes and humans

Directory of Open Access Journals (Sweden)

Chen-Xia Yang

2017-03-01

Full Text Available With the consideration of mechanism of prevention and control for the spread of dengue fever, a mathematical model of dengue fever dynamical transmission between mosquitoes and humans, incorporating a vector control strategy of impulsive culling of mosquitoes, is proposed in this paper. By using the comparison principle, Floquet theorem and some of analytical methods, we obtain the basic reproductive number $\\mathcal{R}_0$ for this infectious disease, which illustrates the stability of the disease-free periodic solution and the uniform persistence of the disease. Further, the explicit conditions determining the backward or forward bifurcation are obtained and the culling rate $\\phi$ is a major effect on the occurrence of backward bifurcation. Finally, numerical simulations are given to verify the correctness of theoretical results and the most efficiency of vector control strategy.

Superior infectivity for mosquito vectors contributes to competitive displacement among strains of dengue virus

Directory of Open Access Journals (Sweden)

Schirtzinger Erin E

2008-02-01

Full Text Available Abstract Background Competitive displacement of a weakly virulent pathogen strain by a more virulent strain is one route to disease emergence. However the mechanisms by which pathogens compete for access to hosts are poorly understood. Among vector-borne pathogens, variation in the ability to infect vectors may effect displacement. The current study focused on competitive displacement in dengue virus serotype 3 (DENV3, a mosquito-borne pathogen of humans. In Sri Lanka in the 1980's, a native DENV3 strain associated with relatively mild dengue disease was displaced by an invasive DENV3 strain associated with the most severe disease manifestations, dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS, resulting in an outbreak of DHF/DSS. Here we tested the hypothesis that differences between the invasive and native strain in their infectivity for Aedes aegypti mosquitoes, the primary vector of DENV, contributed to the competitive success of the invasive strain Results To be transmitted by a mosquito, DENV must infect and replicate in the midgut, disseminate into the hemocoel, infect the salivary glands, and be released into the saliva. The ability of the native and invasive DENV3 strains to complete the first three steps of this process in Aedes aegypti mosquitoes was measured in vivo. The invasive strain infected a similar proportion of mosquitoes as the native strain but replicated to significantly higher titers in the midgut and disseminated with significantly greater efficiency than the native strain. In contrast, the native and invasive strain showed no significant difference in replication in cultured mosquito, monkey or human cells. Conclusion The invasive DENV3 strain infects and disseminates in Ae. aegypti more efficiently than the displaced native DENV3 strain, suggesting that the invasive strain is transmitted more efficiently. Replication in cultured cells did not adequately characterize the known phenotypic differences between

Vector borne diseases

OpenAIRE

Melillo Fenech, Tanya

2010-01-01

A vector-borne disease is one in which the pathogenic microorganism is transmitted from an infected individual to another individual by an arthropod or other agent. The transmission depends upon the attributes and requirements of at least three different Iiving organisms : the pathologic agent which is either a virus, protozoa, bacteria or helminth (worm); the vector, which is commonly an arthropod such as ticks or mosquitoes; and the human host.

Co-occurrence of viruses and mosquitoes at the vectors' optimal climate range: An underestimated risk to temperate regions?

Science.gov (United States)

Blagrove, Marcus S C; Caminade, Cyril; Waldmann, Elisabeth; Sutton, Elizabeth R; Wardeh, Maya; Baylis, Matthew

2017-06-01

Mosquito-borne viruses have been estimated to cause over 100 million cases of human disease annually. Many methodologies have been developed to help identify areas most at risk from transmission of these viruses. However, generally, these methodologies focus predominantly on the effects of climate on either the vectors or the pathogens they spread, and do not consider the dynamic interaction between the optimal conditions for both vector and virus. Here, we use a new approach that considers the complex interplay between the optimal temperature for virus transmission, and the optimal climate for the mosquito vectors. Using published geolocated data we identified temperature and rainfall ranges in which a number of mosquito vectors have been observed to co-occur with West Nile virus, dengue virus or chikungunya virus. We then investigated whether the optimal climate for co-occurrence of vector and virus varies between "warmer" and "cooler" adapted vectors for the same virus. We found that different mosquito vectors co-occur with the same virus at different temperatures, despite significant overlap in vector temperature ranges. Specifically, we found that co-occurrence correlates with the optimal climatic conditions for the respective vector; cooler-adapted mosquitoes tend to co-occur with the same virus in cooler conditions than their warmer-adapted counterparts. We conclude that mosquitoes appear to be most able to transmit virus in the mosquitoes' optimal climate range, and hypothesise that this may be due to proportionally over-extended vector longevity, and other increased fitness attributes, within this optimal range. These results suggest that the threat posed by vector-competent mosquito species indigenous to temperate regions may have been underestimated, whilst the threat arising from invasive tropical vectors moving to cooler temperate regions may be overestimated.

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

International Nuclear Information System (INIS)

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

2012-01-01

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. (letter)

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

Science.gov (United States)

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.

Eilat virus displays a narrow mosquito vector range.

Science.gov (United States)

Nasar, Farooq; Haddow, Andrew D; Tesh, Robert B; Weaver, Scott C

2014-12-17

Most alphaviruses are arthropod-borne and utilize mosquitoes as vectors for transmission to susceptible vertebrate hosts. This ability to infect both mosquitoes and vertebrates is essential for maintenance of most alphaviruses in nature. A recently characterized alphavirus, Eilat virus (EILV), isolated from a pool of Anopheles coustani s.I. is unable to replicate in vertebrate cell lines. The EILV host range restriction occurs at both attachment/entry as well as genomic RNA replication levels. Here we investigated the mosquito vector range of EILV in species encompassing three genera that are responsible for maintenance of other alphaviruses in nature. Susceptibility studies were performed in four mosquito species: Aedes albopictus, A. aegypti, Anopheles gambiae, and Culex quinquefasciatus via intrathoracic and oral routes utilizing EILV and EILV expressing red fluorescent protein (-eRFP) clones. EILV-eRFP was injected at 10(7) PFU/mL to visualize replication in various mosquito organs at 7 days post-infection. Mosquitoes were also injected with EILV at 10(4)-10(1) PFU/mosquito and virus replication was measured via plaque assays at day 7 post-infection. Lastly, mosquitoes were provided bloodmeals containing EILV-eRFP at doses of 10(9), 10(7), 10(5) PFU/mL, and infection and dissemination rates were determined at 14 days post-infection. All four species were susceptible via the intrathoracic route; however, replication was 10-100 fold less than typical for most alphaviruses, and infection was limited to midgut-associated muscle tissue and salivary glands. A. albopictus was refractory to oral infection, while A. gambiae and C. quinquefasciatus were susceptible only at 10(9) PFU/mL dose. In contrast, A. aegypti was susceptible at both 10(9) and 10(7) PFU/mL doses, with body infection rates of 78% and 63%, and dissemination rates of 26% and 8%, respectively. The exclusion of vertebrates in its maintenance cycle may have facilitated the adaptation of EILV to a single

[Biological factors influencing infectious diseases transmitted by invasive species of mosquitoes].

Science.gov (United States)

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.

Mitigating Mosquito Disease Vectors with Citizen Science: a Review of the GLOBE Observer Mosquito Habitat Mapper Pilot and Implications for Wide-scale Implementation

Science.gov (United States)

Riebeek Kohl, H.; Low, R.; Boger, R. A.; Schwerin, T. G.; Janney, D. W.

2017-12-01

The spread of disease vectors, including mosquitoes, is an increasingly significant global environmental issue driven by a warming climate. In 2017, the GLOBE Observer Program launched a new citizen science initiative to map mosquito habitats using the free GLOBE Observer App for smart phones and tablets. The app guides people to identify mosquito larvae and breeding sites, and then once documented, to eliminate or treat the site to prevent further breeding. It also gives citizen scientists the option to identify the mosquito larvae species to determine whether it is one of three genera that potentially could transmit Zika, dengue fever, yellow fever, chikungunya, and other diseases. This data is uploaded to an international database that is freely available to the public and science community. GLOBE Observer piloted the initiative with educators in the United States, Brazil, and Peru, and it is now open for global participation. This presentation will discuss lessons learned in the pilot phase as well as plans to implement the initiative worldwide in partnership with science museums and science centers. GLOBE Observer is the non-student citizen science arm of the Global Learning and Observations to Benefit the Environment (GLOBE) Program, a long-standing, international science and education program that provides students and citizen scientists with the opportunity to participate in data collection and the scientific process, and contribute meaningfully to our understanding of the Earth system and global environment. GLOBE Observer data collection also includes cloud cover and cloud type and land cover/land use (in late 2017).

Germ line transformation of the yellow fever mosquito, Aedes aegypti, mediated by transpositional insertion of a piggyBac vector.

Science.gov (United States)

Lobo, N F; Hua-Van, A; Li, X; Nolen, B M; Fraser, M J

2002-04-01

Mosquito-vectored diseases such as yellow fever and dengue fever continue to have a substantial impact on human populations world-wide. Novel strategies for control of these mosquito vectored diseases can arise through the development of reliable systems for genetic manipulation of the insect vector. A piggyBac vector marked with the Drosophila melanogaster cinnabar (cn) gene was used to transform the white-eyed khw strain of Aedes aegypti. Microinjection of preblastoderm embryos resulted in four families of cinnabar transformed insects. An overall transformation frequency of 4%, with a range of 0% to as high as 13% for individual experiments, was achieved when using a heat-shock induced transposase providing helper plasmid. Southern hybridizations indicated multiple insertion events in three of four transgenic lines, while the presence of duplicated target TTAA sites at either ends of individual insertions confirmed characteristic piggyBac transposition events in these three transgenic lines. The transgenic phenotype has remained stable for more than twenty generations. The transformations effected using the piggyBac element establish the potential of this element as a germ-line transformation vector for Aedine mosquitoes.

Assessment of Climate Change and Vector-borne Diseases in the United States

Science.gov (United States)

Monaghan, A. J.; Beard, C. B.; Eisen, R. J.; Barker, C. M.; Garofalo, J.; Hahn, M.; Hayden, M.; Ogden, N.; Schramm, P.

2016-12-01

Vector-borne diseases are illnesses that are transmitted by vectors, which include mosquitoes, ticks, and fleas. The seasonality, distribution, and prevalence of vector-borne diseases are influenced significantly by climate factors, primarily high and low temperature extremes and precipitation patterns. In this presentation we summarize key findings from Chapter 5 ("Vector-borne Diseases") of the recently published USGCRP Scientific Assessment of the Impacts of Climate Change on Human Health in the United States. Climate change is expected to alter geographic and seasonal distributions of vectors and vector-borne diseases, leading to earlier activity and northward range expansion of ticks capable of carrying the bacteria that cause Lyme disease and other pathogens, and influencing the distribution, abundance and prevalence of infection in mosquitoes that transmit West Nile virus and other pathogens. The emergence or reemergence of vector-borne pathogens is also likely.

Wolbachia-a foe for mosquitoes

Directory of Open Access Journals (Sweden)

Nadipinayakanahalli Munikrishnappa Guruprasad

2014-02-01

Full Text Available Mosquitoes act as vectors for a wide range of viral and parasitic infectious diseases such as malaria, dengue, Chickungunya, lymphatic filariasis, Japanese encephalitis and West Nile virus in humans as well as in animals. Although a wide range of insecticides are used to control mosquitoes, it has only resulted in development of resistance to such insecticides. The evolution of insecticide resistance and lack of vaccines for many mosquito-borne diseases have made these arthropods highly harmful vectors. Recently, a novel approach to control mosquitoes by transinfection of life shortening maternally transmitted endo-symbiont Wolbachia wMelPop strain from fruitfly Drosophila into mosquito population has been developed by researchers. The wMelPop strain up-regulated the immune gene expression in mosquitoes thereby reducing the dengue and Chickungunya viral replication in Aedes aegypti, and also it significantly reduced the Plasmodium level in Anopheles gambiae. Here, we discuss the strategy of using Wolbachia in control of vector-borne diseases of mosquitoes.

Effects of Zika Virus Strain and Aedes Mosquito Species on Vector Competence

Science.gov (United States)

Bialosuknia, Sean M.; Zink, Steven D.; Brecher, Matthew; Ehrbar, Dylan J.; Morrissette, Madeline N.; Kramer, Laura D.

2017-01-01

In the Western Hemisphere, Zika virus is thought to be transmitted primarily by Aedes aegypti mosquitoes. To determine the extent to which Ae. albopictus mosquitoes from the United States are capable of transmitting Zika virus and the influence of virus dose, virus strain, and mosquito species on vector competence, we evaluated multiple doses of representative Zika virus strains in Ae. aegypti and Ae. albopictus mosquitoes. Virus preparation (fresh vs. frozen) significantly affected virus infectivity in mosquitoes. We calculated 50% infectious doses to be 6.1–7.5 log10 PFU/mL; minimum infective dose was 4.2 log10 PFU/mL. Ae. albopictus mosquitoes were more susceptible to infection than Ae. aegypti mosquitoes, but transmission efficiency was higher for Ae. aegypti mosquitoes, indicating a transmission barrier in Ae. albopictus mosquitoes. Results suggest that, although Zika virus transmission is relatively inefficient overall and dependent on virus strain and mosquito species, Ae. albopictus mosquitoes could become major vectors in the Americas. PMID:28430564

Effects of Zika Virus Strain and Aedes Mosquito Species on Vector Competence.

Science.gov (United States)

Ciota, Alexander T; Bialosuknia, Sean M; Zink, Steven D; Brecher, Matthew; Ehrbar, Dylan J; Morrissette, Madeline N; Kramer, Laura D

2017-07-01

In the Western Hemisphere, Zika virus is thought to be transmitted primarily by Aedes aegypti mosquitoes. To determine the extent to which Ae. albopictus mosquitoes from the United States are capable of transmitting Zika virus and the influence of virus dose, virus strain, and mosquito species on vector competence, we evaluated multiple doses of representative Zika virus strains in Ae. aegypti and Ae. albopictus mosquitoes. Virus preparation (fresh vs. frozen) significantly affected virus infectivity in mosquitoes. We calculated 50% infectious doses to be 6.1-7.5 log 10 PFU/mL; minimum infective dose was 4.2 log 10 PFU/mL. Ae. albopictus mosquitoes were more susceptible to infection than Ae. aegypti mosquitoes, but transmission efficiency was higher for Ae. aegypti mosquitoes, indicating a transmission barrier in Ae. albopictus mosquitoes. Results suggest that, although Zika virus transmission is relatively inefficient overall and dependent on virus strain and mosquito species, Ae. albopictus mosquitoes could become major vectors in the Americas.

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.

Science.gov (United States)

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

Direct and indirect immunosuppression by a malaria parasite in its mosquito vector

NARCIS (Netherlands)

Boëte, C.H.J.J.; Paul, R.E.L.; Koëlla, J.C.

2004-01-01

Malaria parasites develop as oocysts within the haemocoel of their mosquito vector during a period that is longer than the average lifespan of many of their vectors. How can they escape from the mosquito's immune responses during their long development? Whereas older oocysts might camouflage

Chromobacterium Csp_P reduces malaria and dengue infection in vector mosquitoes and has entomopathogenic and in vitro anti-pathogen activities.

Science.gov (United States)

Ramirez, Jose Luis; Short, Sarah M; Bahia, Ana C; Saraiva, Raul G; Dong, Yuemei; Kang, Seokyoung; Tripathi, Abhai; Mlambo, Godfree; Dimopoulos, George

2014-10-01

Plasmodium and dengue virus, the causative agents of the two most devastating vector-borne diseases, malaria and dengue, are transmitted by the two most important mosquito vectors, Anopheles gambiae and Aedes aegypti, respectively. Insect-bacteria associations have been shown to influence vector competence for human pathogens through multi-faceted actions that include the elicitation of the insect immune system, pathogen sequestration by microbes, and bacteria-produced anti-pathogenic factors. These influences make the mosquito microbiota highly interesting from a disease control perspective. Here we present a bacterium of the genus Chromobacterium (Csp_P), which was isolated from the midgut of field-caught Aedes aegypti. Csp_P can effectively colonize the mosquito midgut when introduced through an artificial nectar meal, and it also inhibits the growth of other members of the midgut microbiota. Csp_P colonization of the midgut tissue activates mosquito immune responses, and Csp_P exposure dramatically reduces the survival of both the larval and adult stages. Ingestion of Csp_P by the mosquito significantly reduces its susceptibility to Plasmodium falciparum and dengue virus infection, thereby compromising the mosquito's vector competence. This bacterium also exerts in vitro anti-Plasmodium and anti-dengue activities, which appear to be mediated through Csp_P -produced stable bioactive factors with transmission-blocking and therapeutic potential. The anti-pathogen and entomopathogenic properties of Csp_P render it a potential candidate for the development of malaria and dengue control strategies.

Zika mosquito vectors: the jury is still out [version 1; referees: 5 approved

Directory of Open Access Journals (Sweden)

Walter S. Leal

2016-10-01

Full Text Available After a 40-year hiatus, the International Congress of Entomology (ICE 2016 convened in Orlando, Florida (September 25-30, 2016. One of the symposia at ICE 2016, the Zika Symposium, covered multiple aspects of the Zika epidemic, including epidemiology, sexual transmission, genetic tools for reducing transmission, and particularly vector competence. While there was a consensus among participants that the yellow fever mosquito, Aedes aegypti, is a vector of the Zika virus, there is growing evidence indicating that the range of mosquito vectors might be wider than anticipated. In particular, three independent groups from Canada, China, and Brazil presented and discussed laboratory and field data strongly suggesting that the southern house mosquito, Culex quinquefasciatus, also known as the common mosquito, is highly likely to be a vector in certain environments.

Zika mosquito vectors: the jury is still out [version 2; referees: 5 approved

Directory of Open Access Journals (Sweden)

Walter S. Leal

2016-11-01

Full Text Available After a 40-year hiatus, the International Congress of Entomology (ICE 2016 convened in Orlando, Florida (September 25-30, 2016. One of the symposia at ICE 2016, the Zika Symposium, covered multiple aspects of the Zika epidemic, including epidemiology, sexual transmission, genetic tools for reducing transmission, and particularly vector competence. While there was a consensus among participants that the yellow fever mosquito, Aedes aegypti, is a vector of the Zika virus, there is growing evidence indicating that the range of mosquito vectors might be wider than anticipated. In particular, three independent groups from Canada, China, and Brazil presented and discussed laboratory and field data strongly suggesting that the southern house mosquito, Culex quinquefasciatus, also known as the common mosquito, is highly likely to be a vector in certain environments.

The developmental transcriptome of the mosquito Aedes aegypti, an invasive species and major arbovirus vector.

Science.gov (United States)

Akbari, Omar S; Antoshechkin, Igor; Amrhein, Henry; Williams, Brian; Diloreto, Race; Sandler, Jeremy; Hay, Bruce A

2013-09-04

Mosquitoes are vectors of a number of important human and animal diseases. The development of novel vector control strategies requires a thorough understanding of mosquito biology. To facilitate this, we used RNA-seq to identify novel genes and provide the first high-resolution view of the transcriptome throughout development and in response to blood feeding in a mosquito vector of human disease, Aedes aegypti, the primary vector for Dengue and yellow fever. We characterized mRNA expression at 34 distinct time points throughout Aedes development, including adult somatic and germline tissues, by using polyA+ RNA-seq. We identify a total of 14,238 novel new transcribed regions corresponding to 12,597 new loci, as well as many novel transcript isoforms of previously annotated genes. Altogether these results increase the annotated fraction of the transcribed genome into long polyA+ RNAs by more than twofold. We also identified a number of patterns of shared gene expression, as well as genes and/or exons expressed sex-specifically or sex-differentially. Expression profiles of small RNAs in ovaries, early embryos, testes, and adult male and female somatic tissues also were determined, resulting in the identification of 38 new Aedes-specific miRNAs, and ~291,000 small RNA new transcribed regions, many of which are likely to be endogenous small-interfering RNAs and Piwi-interacting RNAs. Genes of potential interest for transgene-based vector control strategies also are highlighted. Our data have been incorporated into a user-friendly genome browser located at www.Aedes.caltech.edu, with relevant links to Vectorbase (www.vectorbase.org).

Population genetics of the Asian tiger mosquito Aedes albopictus, an invasive vector of human diseases

Science.gov (United States)

Goubert, C; Minard, G; Vieira, C; Boulesteix, M

2016-01-01

The Asian tiger mosquito Aedes albopictus is currently one of the most threatening invasive species in the world. Native to Southeast Asia, the species has spread throughout the world in the past 30 years and is now present in every continent but Antarctica. Because it was the main vector of recent Dengue and Chikungunya outbreaks, and because of its competency for numerous other viruses and pathogens such as the Zika virus, A. albopictus stands out as a model species for invasive diseases vector studies. A synthesis of the current knowledge about the genetic diversity of A. albopictus is needed, knowing the interplays between the vector, the pathogens, the environment and their epidemiological consequences. Such resources are also valuable for assessing the role of genetic diversity in the invasive success. We review here the large but sometimes dispersed literature about the population genetics of A. albopictus. We first debate about the experimental design of these studies and present an up-to-date assessment of the available molecular markers. We then summarize the main genetic characteristics of natural populations and synthesize the available data regarding the worldwide structuring of the vector. Finally, we pinpoint the gaps that remain to be addressed and suggest possible research directions. PMID:27273325

PIWIs Go Viral: Arbovirus-Derived piRNAs in Vector Mosquitoes.

Directory of Open Access Journals (Sweden)

Pascal Miesen

2016-12-01

Full Text Available Vector mosquitoes are responsible for transmission of the majority of arthropod-borne (arbo- viruses. Virus replication in these vectors needs to be sufficiently high to permit efficient virus transfer to vertebrate hosts. The mosquito immune response therefore is a key determinant for arbovirus transmission. Mosquito antiviral immunity is primarily mediated by the small interfering RNA pathway. Besides this well-established antiviral machinery, the PIWI-interacting RNA (piRNA pathway processes viral RNA into piRNAs. In recent years, significant progress has been made in characterizing the biogenesis and function of these viral piRNAs. In this review, we discuss these developments, identify knowledge gaps, and suggest directions for future research.

Insecticide mixtures for mosquito net impregnation against malaria vectors

Directory of Open Access Journals (Sweden)

Corbel V.

2002-09-01

Full Text Available Insecticides belonging to the pyrethroid family are the only compounds currently available for the treatment of mosquito nets. Unfortunately, some malaria vector species have developed resistance to pyrethroids and the lack of alternative chemical categories is a great concern. One strategy for resistance management would be to treat mosquito nets with a mixture associating two insecticides having different modes of action. This study presents the results obtained with insecticide mixtures containing several proportions of bifenthrin (a pyrethroid insecticide and carbosulfan (a carbamate insecticide. The mixtures were sprayed on mosquito net samples and their efficacy were tested against a susceptible strain of Anopheles gambiae, the major malaria vector in Africa. A significant synergism was observed with a mixture containing 25 mg/m2 of bifenthrin (half the recommended dosage for treated nets and 6.25 mg/m2 of carbosulfan (about 2 % of the recommended dosage. The observed mortality was significantly more than expected in the absence of any interaction (80 % vs 41 % and the knock-down effect was maintained, providing an effective barrier against susceptible mosquitoes.

Mosquitoes in the Danube Delta: searching for vectors of filarioid helminths and avian malaria

Czech Academy of Sciences Publication Activity Database

Ionică, A.M.; Zittra, C.; Wimmer, V.; Leitner, N.; Votýpka, Jan; Modrý, David; Mihalca, A. D.; Fuehrer, H.-P.

2017-01-01

Roč. 10, JUL 5 (2017), č. článku 324. ISSN 1756-3305 Institutional support: RVO:60077344 Keywords : Danube Delta * filarioids * avian malaria * mosquito vectors Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine OBOR OECD: Tropical medicine Impact factor: 3.080, year: 2016

Effects of Climate and Climate Change on Vectors and Vector-Borne Diseases: Ticks Are Different.

Science.gov (United States)

Ogden, Nick H; Lindsay, L Robbin

2016-08-01

There has been considerable debate as to whether global risk from vector-borne diseases will be impacted by climate change. This has focussed on important mosquito-borne diseases that are transmitted by the vectors from infected to uninfected humans. However, this debate has mostly ignored the biological diversity of vectors and vector-borne diseases. Here, we review how climate and climate change may impact those most divergent of arthropod disease vector groups: multivoltine insects and hard-bodied (ixodid) ticks. We contrast features of the life cycles and behaviour of these arthropods, and how weather, climate, and climate change may have very different impacts on the spatiotemporal occurrence and abundance of vectors, and the pathogens they transmit. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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.

Possible impact of rising sea levels on vector-borne infectious diseases

Directory of Open Access Journals (Sweden)

Surendran Sinnathamby N

2011-01-01

Full Text Available Abstract Background Vector-borne infectious diseases are a significant cause of human and animal mortality and morbidity. Modeling studies predict that changes in climate that accompany global warming will alter the transmission risk of many vector-borne infectious diseases in different parts of the world. Global warming will also raise sea levels, which will lead to an increase in saline and brackish water bodies in coastal areas. The potential impact of rising sea levels, as opposed to climate change, on the prevalence of vector-borne infectious diseases has hitherto been unrecognised. Presentation of the hypothesis Mosquito species possessing salinity-tolerant larvae and pupae, and capable of transmitting arboviruses and parasites are found in many parts of the world. An expansion of brackish and saline water bodies in coastal areas, associated with rising sea levels, can increase densities of salinity-tolerant vector mosquitoes and lead to the adaptation of freshwater vectors to breed in brackish and saline waters. The breeding of non-mosquito vectors may also be influenced by salinity changes in coastal habitats. Higher vector densities can increase transmission of vector-borne infectious diseases in coastal localities, which can then spread to other areas. Testing the hypothesis The demonstration of increases in vector populations and disease prevalence that is related to an expansion of brackish/saline water bodies in coastal areas will provide the necessary supportive evidence. However the implementation of specific vector and disease control measures to counter the threat will confound the expected findings. Implications of the hypothesis Rising sea levels can act synergistically with climate change and then interact in a complex manner with other environmental and socio-economic factors to generate a greater potential for the transmission of vector-borne infectious diseases. The resulting health impacts are likely to be particularly

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

KAUST Repository

Crawford, Jacob E.

2017-02-20

BackgroundThe 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.ResultsTo 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.ConclusionsWe 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

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.

Science.gov (United States)

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.

Mosquitos Culicidae como vetores emergentes de infecções Culicidae mosquitoes as emerging vectors of diseases

Directory of Open Access Journals (Sweden)

Oswaldo Paulo Forattini

1998-12-01

Full Text Available Apresenta-se sucinta revisão do relacionamento entre as chamadas infecções emergentes e o conceito de vetores emergentes. Estes são entendidos não apenas no que concerne aos que são descritos como tais, de forma nova, mas também aqueles com acentuadas mudanças de comportamento. Os fatores específicos que propiciam esse fenômeno identificam-se à poderosa influência humana sobre o ambiente. Assim, aquele construído pelo homem e conhecido como antrópico representa a função de pressão seletiva que induz as populações vetoras a se adaptarem às novas circunstâncias. Nelas inclui-se fatores ecológicos ambientais, ou demográficos, que incrementam o contato com os novos comportamentos vetoriais. Relata-se o encontro de criadouros anômalos de mosquitos Culicidae nas Américas. A interpretação desses encontros é feita visando à vigilância epidemiológica. O significado dessa emergência ou reemergência pode se traduzir no aparecimento de problemas epidemiológicos. Sugere-se que, em sendo assim, a vigilância epidemiológica deva ser feita em grau global.A review is presented of the relationships between the so-called emerging infectious diseases and what may be defined as emerging vectors. These include not only those that have recently appeared but also those that present remarkable behavioral changes. Specific factors leading to that emergence can be associated with the powerful human influence on the environment. So the man-made, i.e. anthropic environment, exercises a selective pressure inducing vector populations to adapt to new circumstances. These may arise from ecological, environmental, or demographic factors that increase contact with the new vector. With this in mind, data on anomalous Culicidae breeding places in the Americas are reported. An interpretation of these findings is offered in the light of epidemiological surveillance. The question is whether vector emergence or re-emergence may constitute an

Additional records of vector mosquito diversity collected from Al Khor district of North-eastern Qatar

Directory of Open Access Journals (Sweden)

Mahmoud Mohammed Kardousha

2015-10-01

Full Text Available Objective: To survey mosquito diversity in the north-eastern area, which includes the most important gas industrial city in Qatar, and to investigate the potential mosquitoes for transmitting diseases. Methods: A study was performed from September 2009 until June 2011 in Al-Khor district of North-eastern Qatar. Five localities were selected for larval collection: Al Khor City (the main city, Al Dhakira, Ras Laffan (gas industrial city, Simsimah and Al Ghuwariyah. The survey was carried out by using different sampling methods and covering all expected natural breeding sites. The larvae were collected, preserved and transferred to the laboratory for identification. Results: Our findings revealed that 10 species of mosquito larvae had been detected from the area and five of them were new records in Qatar. The species encountered were: Ochlerotatus caspius (Pallas 1771, Anopheles stephensi (Liston 1901, Culex quinquefasciatus (Say 1823 (Cx. quinquefasciatus, Culex pipiens biotype molestus (Forskal 1775 (Cx. pipiens, Culex univittatus (Theobald 1901, Culex pusillus (Macquart 1850, Culex tritaeniorhynchus (Giles 1901 (Cx. tritaeniorhynchus, Culex laticinctus (Edwards 1913, Culex sitiens (Weidmann 1828 and Culex perexiguus (Theobald 1901. The new recorded species were Cx. quinquefasciatus, Cx. tritaeniorhynchus, Culex laticinctus, Culex sitiens and Culex perexiguus. The most prevalent type was Cx. pipiens molestus (31.29% and followed by Culex pusillus and Cx. quinquefasciatus which have relatively similar prevalence of 18.72% and 18.52% respectively. Anopheles stephensi was an established vector for malaria. Cx. pipiens molestus and Cx. quinquefasciatus were vectors of West Nile virus and filariasis. Cx. tritaeniorhynchus was established as a vector of Rift Valley virus and Culex univittatus was the main vector of Sindbis virus. Conclusions: The north-eastern area of Qatar harbors is the most important industrial city in the country, which has

Mosquito Vectors and the Globalization of Plasmodium falciparum Malaria.

Science.gov (United States)

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.

Geostatistical evaluation of integrated marsh management impact on mosquito vectors using before-after-control-impact (BACI) design

OpenAIRE

Rochlin, Ilia; Iwanejko, Tom; Dempsey, Mary E; Ninivaggi, Dominick V

2009-01-01

Abstract Background In many parts of the world, salt marshes play a key ecological role as the interface between the marine and the terrestrial environments. Salt marshes are also exceedingly important for public health as larval habitat for mosquitoes that are vectors of disease and significant biting pests. Although grid ditching and pesticides have been effective in salt marsh mosquito control, marsh degradation and other environmental considerations compel a different approach. Targeted h...

Nanoparticles in the fight against mosquito-borne diseases: bioactivity of Bruguiera cylindrica-synthesized nanoparticles against dengue virus DEN-2 (in vitro) and its mosquito vector Aedes aegypti (Diptera: Culicidae).

Science.gov (United States)

Murugan, Kadarkarai; Dinesh, Devakumar; Paulpandi, Manickam; Althbyani, Abdulaziz Dakhellah Meqbel; Subramaniam, Jayapal; Madhiyazhagan, Pari; Wang, Lan; Suresh, Udaiyan; Kumar, Palanisamy Mahesh; Mohan, Jagathish; Rajaganesh, Rajapandian; Wei, Hui; Kalimuthu, Kandasamy; Parajulee, Megha N; Mehlhorn, Heinz; Benelli, Giovanni

2015-12-01

Mosquitoes are blood-feeding insects serving as the most important vectors for spreading human pathogens and parasites. Dengue is a viral disease mainly vectored through the bite of Aedes mosquitoes. Its transmission has recently increased in urban and semi-urban areas of tropical and subtropical regions worldwide, becoming a major international public health concern. There is no specific treatment for dengue. Its prevention and control solely depend on effective vector control measures. Mangrove plants have been used in Indian traditional medicine for a wide array of purposes. In this research, we proposed a method for biosynthesis of antiviral and mosquitocidal silver nanoparticles (AgNP) using the aqueous extract of Bruguiera cylindrica leaves. AgNP were characterized using a variety of biophysical analyses, including UV-visible spectrophotometry, Fourier-transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Bruguiera cilyndrica aqueous extract and green-synthesized AgNP were tested against the primary dengue vector Aedes aegypti. AgNP were the most effective. LC50 values ranged from 8.93 ppm (larva I) to 30.69 ppm (pupa). In vitro experiments showed that 30 μg/ml of AgNP significantly inhibited the production of dengue viral envelope (E) protein in vero cells and downregulated the expression of dengue viral E gene. Concerning nontarget effects, we observed that the predation efficiency of Carassius auratus against A. aegypti was not affected by exposure at sublethal doses of AgNP. Predation in the control was 71.81 % (larva II) and 50.43 % (larva III), while in an AgNP-treated environment, predation was boosted to 90.25 and 76.81 %, respectively. Overall, this study highlights the concrete potential of green-synthesized AgNP in the fight against dengue virus. Furthermore, B. cylindrica-synthesized AgNP can be employed at low doses to reduce larval and pupal population of A. aegypti, without detrimental

Community diversity of mosquitoes and their microbes across different habitats endemic for West Nile Virus and other arthropod-borne diseases

Science.gov (United States)

Liu, R.; Bennett, S. N.; Thongsripong, P.; Chandler, J. S.

2013-12-01

Mosquitoes have long been vectors for disease, and humans, birds, and other vertebrates have served their role as hosts in the transmission cycle of arthropod-borne viruses. In California, there are several mosquito species that act as vectors, transmitting such disease agents as Western equine and St. Louis encephalitis viruses, filarial nematodes, Plasmodium (which causes malaria), and West Nile virus (WNV). Last year (2012-2013), California had over 450 reported cases of West Nile Virus in humans (http://westnile.ca.gov/). To begin to understand mosquitoes and their role in the bay area as vectors of diseases, including West Nile Virus, we trapped mosquitoes from various sites and examined their microbiomes, including bacteria, fungi, viruses, and eukaryotes. Study sites were in Marin, San Mateo, and San Francisco counties, in areas that represented, respectively, rural, suburban, and urban habitats. The mosquitoes were identified through morphological characteristics, and verified molecularly by sequencing of the cytochrome oxidase I (COI) gene extracted from a leg. Most mosquitoes were collected from San Mateo and Mill Valley and were identified as Culiseta incidens. Data from traditional culture-based and next-generation 454 sequencing methods applied to mosquito whole bodies, representing their microbiomes, will be discussed, to determine how mosquito and microbial diversity varies across sites sampled in the San Francisco Bay area.

Adult vector control, mosquito ecology and malaria transmission.

Science.gov (United States)

Brady, Oliver J; Godfray, H Charles J; Tatem, Andrew J; Gething, Peter W; Cohen, Justin M; McKenzie, F Ellis; Alex Perkins, T; Reiner, Robert C; Tusting, Lucy S; Scott, Thomas W; Lindsay, Steven W; Hay, Simon I; Smith, David L

2015-03-01

Standard advice regarding vector control is to prefer interventions that reduce the lifespan of adult mosquitoes. The basis for this advice is a decades-old sensitivity analysis of 'vectorial capacity', a concept relevant for most malaria transmission models and based solely on adult mosquito population dynamics. Recent advances in micro-simulation models offer an opportunity to expand the theory of vectorial capacity to include both adult and juvenile mosquito stages in the model. In this study we revisit arguments about transmission and its sensitivity to mosquito bionomic parameters using an elasticity analysis of developed formulations of vectorial capacity. We show that reducing adult survival has effects on both adult and juvenile population size, which are significant for transmission and not accounted for in traditional formulations of vectorial capacity. The elasticity of these effects is dependent on various mosquito population parameters, which we explore. Overall, control is most sensitive to methods that affect adult mosquito mortality rates, followed by blood feeding frequency, human blood feeding habit, and lastly, to adult mosquito population density. These results emphasise more strongly than ever the sensitivity of transmission to adult mosquito mortality, but also suggest the high potential of combinations of interventions including larval source management. This must be done with caution, however, as policy requires a more careful consideration of costs, operational difficulties and policy goals in relation to baseline transmission. © The Author 2015. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene.

"Bird biting" mosquitoes and human disease: a review of the role of Culex pipiens complex mosquitoes in epidemiology.

Science.gov (United States)

Farajollahi, Ary; Fonseca, Dina M; Kramer, Laura D; Marm Kilpatrick, A

2011-10-01

The transmission of vector-borne pathogens is greatly influenced by the ecology of their vector, which is in turn shaped by genetic ancestry, the environment, and the hosts that are fed on. One group of vectors, the mosquitoes in the Culex pipiens complex, play key roles in the transmission of a range of pathogens including several viruses such as West Nile and St. Louis encephalitis viruses, avian malaria (Plasmodium spp.), and filarial worms. The Cx. pipiens complex includes Culex pipiens pipiens with two forms, pipiens and molestus, Culex pipiens pallens, Culex quinquefasciatus, Culex australicus, and Culex globocoxitus. While several members of the complex have limited geographic distributions, Cx. pipienspipiens and Cx. quinquefasciatus are found in all known urban and sub-urban temperate and tropical regions, respectively, across the world, where they are often principal disease vectors. In addition, hybrids are common in areas of overlap. Although gaps in our knowledge still remain, the advent of genetic tools has greatly enhanced our understanding of the history of speciation, domestication, dispersal, and hybridization. We review the taxonomy, genetics, evolution, behavior, and ecology of members of the Cx. pipiens complex and their role in the transmission of medically important pathogens. The adaptation of Cx. pipiens complex mosquitoes to human-altered environments led to their global distribution through dispersal via humans and, combined with their mixed feeding patterns on birds and mammals (including humans), increased the transmission of several avian pathogens to humans. We highlight several unanswered questions that will increase our ability to control diseases transmitted by these mosquitoes. Copyright © 2011 Elsevier B.V. All rights reserved.

Spread of Zika virus:The key role of mosquito vector control

Institute of Scientific and Technical Information of China (English)

Giovanni Benelli

2016-01-01

Mosquitoes (Diptera: Culicidae) represent a key threat for millions of humans and ani-mals worldwide, since they act as vectors for important parasites and pathogens, including malaria, filariasis and a wide number of arboviruses. The recent outbreaks of Zika virus infections occurring in South America, Central America, and the Caribbean, represent the most recent four arrivals of important arboviruses in the western hemi-sphere, over the last 20 years, namely dengue, West Nile virus, and chikungunya. Since there are no specific treatments for Zika virus and the other arboviruses mentioned above, it should be highlighted that the eco-friendly and effective control of mosquito vectors is of pivotal importance. Besides radiation, transgenic and symbiont-based mosquito control approaches, an effective option may be the employ of biological control agents of mosquito young instars, in presence of ultra-low quantities of green-synthesized nano-particles, which magnify their predation efficiency. Furthermore, behaviour-based control tools relying on the employ of swarming behaviour manipulation (i.e. the“lure and kill”approach), pheromone traps, sound traps need further research attention. In particular, detailed basic information on the physical and chemical cues routing mosquito swarming and mating dynamics is urgently required.

Spread of Zika virus:The key role of mosquito vector control

Institute of Scientific and Technical Information of China (English)

Giovanni Benelli

2016-01-01

Mosquitoes(Diptera: Culicidae) represent a key threat for millions of humans and animals worldwide, since they act as vectors for important parasites and pathogens,including malaria, filariasis and a wide number of arboviruses. The recent outbreaks of Zika virus infections occurring in South America, Central America, and the Caribbean,represent the most recent four arrivals of important arboviruses in the western hemisphere, over the last 20 years, namely dengue, West Nile virus, and chikungunya. Since there are no specific treatments for Zika virus and the other arboviruses mentioned above,it should be highlighted that the eco-friendly and effective control of mosquito vectors is of pivotal importance. Besides radiation, transgenic and symbiont-based mosquito control approaches, an effective option may be the employ of biological control agents of mosquito young instars, in presence of ultra-low quantities of green-synthesized nanoparticles, which magnify their predation efficiency. Furthermore, behaviour-based control tools relying on the employ of swarming behaviour manipulation(i.e. the "lure and kill"approach), pheromone traps, sound traps need further research attention. In particular,detailed basic information on the physical and chemical cues routing mosquito swarming and mating dynamics is urgently required.

Spread of Zika virus: The key role of mosquito vector control

Directory of Open Access Journals (Sweden)

Giovanni Benelli

2016-06-01

Full Text Available Mosquitoes (Diptera: Culicidae represent a key threat for millions of humans and animals worldwide, since they act as vectors for important parasites and pathogens, including malaria, filariasis and a wide number of arboviruses. The recent outbreaks of Zika virus infections occurring in South America, Central America, and the Caribbean, represent the most recent four arrivals of important arboviruses in the western hemisphere, over the last 20 years, namely dengue, West Nile virus, and chikungunya. Since there are no specific treatments for Zika virus and the other arboviruses mentioned above, it should be highlighted that the eco-friendly and effective control of mosquito vectors is of pivotal importance. Besides radiation, transgenic and symbiont-based mosquito control approaches, an effective option may be the employ of biological control agents of mosquito young instars, in presence of ultra-low quantities of green-synthesized nanoparticles, which magnify their predation efficiency. Furthermore, behaviour-based control tools relying on the employ of swarming behaviour manipulation (i.e. the “lure and kill” approach, pheromone traps, sound traps need further research attention. In particular, detailed basic information on the physical and chemical cues routing mosquito swarming and mating dynamics is urgently required.

The importance of being urgent: The impact of surveillance target and scale on mosquito-borne disease control

Directory of Open Access Journals (Sweden)

Samantha R. Schwab

2018-06-01

Full Text Available With the emergence or re-emergence of numerous mosquito-borne diseases in recent years, effective methods for emergency vector control responses are necessary to reduce human infections. Current vector control practices often vary significantly between different jurisdictions, and are executed independently and at different spatial scales. Various types of surveillance information (e.g. number of human infections or adult mosquitoes trigger the implementation of control measures, though the target and scale of surveillance vary locally. This patchy implementation of control measures likely alters the efficacy of control.We modeled six different scenarios, with larval mosquito control occurring in response to surveillance data of different types and at different scales (e.g. across the landscape or in each patch. Our results indicate that: earlier application of larvicide after an escalation of disease risk achieves much greater reductions in human infections than later control implementation; uniform control across the landscape provides better outbreak mitigation than patchy control application; and different types of surveillance data require different levels of sensitivity in their collection to effectively inform control measures. Our simulations also demonstrate a potential logical fallacy of reactive, surveillance-driven vector control: measures stop being implemented as soon as they are deemed effective. This false sense of security leads to patchier control efforts that will do little to curb the size of future vector-borne disease outbreaks. More investment should be placed in collecting high quality information that can trigger early and uniform implementation, while researchers work to discover more informative metrics of human risk to trigger more effective control. Keywords: Zika control, Epidemiological surveillance, Disease surveillance, Mosquito control, Vector-borne disease control, Epidemiological modeling

Emerging Vector-Borne Diseases.

Science.gov (United States)

Huntington, Mark K; Allison, Jay; Nair, Dilip

2016-10-01

Several mosquito-borne viral infections have recently emerged in North America; West Nile virus is the most common in the United States. Although West Nile virus generally causes a self-limited, flulike febrile illness, a serious neuroinvasive form may occur. Dengue is the most common vector-borne viral disease worldwide, and it has been a significant public health threat in the United States since 2009. Known as breakbone fever for its severe myalgias and arthralgias, dengue may cause a hemorrhagic syndrome. Chikungunya also causes flulike febrile illness and disabling arthralgias. Although meningoencephalitis may occur with chikungunya, bleeding is uncommon. Symptoms of Zika virus infection are similar to those of dengue, but milder. Zika virus increases the risk of fetal brain abnormalities, including microcephaly, if a pregnant woman is infected. Zika virus is spread through Aedes albopictus mosquito bites, is transmitted sexually, and may rarely spread nonsexually from person to person. Diagnosis of these vectorborne infections is clinical and serologic, and treatment is supportive. Other, well-established vector-borne diseases are also important. Ehrlichiosis is a tick-borne bacterial disease that presents as a nonspecific syndrome of fever, headache, malaise, and myalgias. It is diagnosed via blood smear testing, with confirmatory serology. Ehrlichiosis is treated with doxycycline. Rickettsial infections are transmitted by fleas, mites, and ticks, and severity ranges from mild to life threatening. Rocky Mountain spotted fever, the most significant rickettsial infection, is primarily a clinical diagnosis that presents as fever, headache, myalgias, petechial rash, and tick exposure. Doxycycline is effective for rickettsial infections if administered promptly. Vector avoidance strategies are critical to the prevention of all of these infections.

The importance of age dependent mortality and the extrinsic incubation period in models of mosquito-borne disease transmission and control.

Directory of Open Access Journals (Sweden)

Steve E Bellan

2010-04-01

Full Text Available Nearly all mathematical models of vector-borne diseases have assumed that vectors die at constant rates. However, recent empirical research suggests that mosquito mortality rates are frequently age dependent. This work develops a simple mathematical model to assess how relaxing the classical assumption of constant mortality affects the predicted effectiveness of anti-vectorial interventions. The effectiveness of mosquito control when mosquitoes die at age dependent rates was also compared across different extrinsic incubation periods. Compared to a more realistic age dependent model, constant mortality models overestimated the sensitivity of disease transmission to interventions that reduce mosquito survival. Interventions that reduce mosquito survival were also found to be slightly less effective when implemented in systems with shorter EIPs. Future transmission models that examine anti-vectorial interventions should incorporate realistic age dependent mortality rates.

Inter-epidemic abundance and distribution of potential mosquito vectors for Rift Valley fever virus in Ngorongoro district, Tanzania

OpenAIRE

Mweya, Clement N.; Kimera, Sharadhuli I.; Mellau, Lesakit S. B.; Mboera, Leonard E. G.

2015-01-01

Background: Rift Valley fever (RVF) is a mosquito-borne viral zoonosis that primarily affects ruminants but also has the capacity to infect humans. Objective: To determine the abundance and distribution of mosquito vectors in relation to their potential role in the virus transmission and maintenance in disease epidemic areas of Ngorongoro district in northern Tanzania. Methods: A cross-sectional entomological investigation was carried out before the suspected RVF outbreak in October 2012. Mos...

Web mapping GIS: GPS under the GIS umbrella for Aedes species dengue and chikungunya vector mosquito surveillance and control

Directory of Open Access Journals (Sweden)

M. Palaniyandi

2014-09-01

Full Text Available The mosquito nuisance and the mosquito borne diseases have become major important challenging public health problems in India especially in the fast developing city like Pondicherry urban agglomeration. The Pondicherry government has been implemented full-fledged mosquito control measures, however, dengue and chikungunya epidemics was accelerating trend in Pondicherry for the recent years, and therefore, the directorate of public health, Pondicherry was requested vector control research centre (VCRC, to conduct a mosquito control evaluation survey. A team of field staff of VCRC headed by the author, Pondicherry, have conducted a detailed reconnaissance survey for collecting the site specifications of houses and the streetwise mosquito data for analyzing the density of vector mosquitoes in the wards / blocks and delineating the areas vulnerable to disease epidemics in the urban areas. The GPS GARMIN 12 XL was used to collect the field data. The ARC GIS 10.0 software was used to map the site locations (houses with mosquito’s data. The digital map of block boundary of Pondicherry was used for mapping purpose. A systematic grid sampling was applied to conduct a rapid survey for mapping Aedes species mosquito genic condition in the urban areas and the coordinates of sites of house information with breeding habitats positive in the grid sectors was collected using GPS, and the mean value of positive habitats was analyzed by quintiles method for mapping. The four blocks were selected for Aedes mosquito survey where the mosquito problem was identified as comparatively high, four numbers of wards were selected from each block, and the 40 number of houses was selected with 100 meter interval distance for mosquito breeding survey in the domestic and peripheral domestic areas in each wards. The problematic areas were identified, highlighted and recommended for web mapping GIS for Aedes mosquito surveillance continuously for monitoring the mosquito control

Approaches to passive mosquito surveillance in the EU

NARCIS (Netherlands)

Kampen, H.; Medlock, J.M.; Vaux, A.G.C.; Koenraadt, C.J.M.; Vliet, van A.J.H.; Bartumeus, F.; Oltra, A.; Sousa, C.A.; Chouin, S.; Werner, D.

2015-01-01

The recent emergence in Europe of invasive mosquitoes and mosquito-borne disease associated with both invasive and native mosquito species has prompted intensified mosquito vector research in most European countries. Central to the efforts are mosquito monitoring and surveillance activities in order

Repelling mosquitoes with essential oils

Science.gov (United States)

Riley, L.

2017-12-01

Mosquitoes carry diseases than can lead to serious illness and death. According to the World Health Organization, mosquitoes infect over 300 million people a year with Malaria and Dengue Fever, two life threatening diseases vectored by mosquitoes. Although insecticides are the most effective way to control mosquitoes, they are not always environmentally friendly. Therefore, alternative tactics should be considered. In this study, we looked at the repellency of various essential oils on female Aedes aegypti through a series of laboratory assays.

Simulating the spread of malaria using a generic transmission model for mosquito-borne infectious diseases

Science.gov (United States)

Kon, Cynthia Mui Lian; Labadin, Jane

2016-06-01

Malaria is a critical infection caused by parasites which are spread to humans through mosquito bites. Approximately half of the world's population is in peril of getting infected by malaria. Mosquito-borne diseases have a standard behavior where they are transmitted in the same manner, only through vector mosquito. Taking this into account, a generic spatial-temporal model for transmission of multiple mosquito-borne diseases had been formulated. Our interest is to reproduce the actual cases of different mosquito-borne diseases using the generic model and then predict future cases so as to improve control and target measures competently. In this paper, we utilize notified weekly malaria cases in four districts in Sarawak, Malaysia, namely Kapit, Song, Belaga and Marudi. The actual cases for 36 weeks, which is from week 39 in 2012 to week 22 in 2013, are compared with simulations of the generic spatial-temporal transmission mosquito-borne diseases model. We observe that the simulation results display corresponding result to the actual malaria cases in the four districts.

Canine vector-borne diseases in Brazil

Science.gov (United States)

Dantas-Torres, Filipe

2008-01-01

Canine vector-borne diseases (CVBDs) are highly prevalent in Brazil and represent a challenge to veterinarians and public health workers, since some diseases are of great zoonotic potential. Dogs are affected by many protozoa (e.g., Babesia vogeli, Leishmania infantum, and Trypanosoma cruzi), bacteria (e.g., Anaplasma platys and Ehrlichia canis), and helminths (e.g., Dirofilaria immitis and Dipylidium caninum) that are transmitted by a diverse range of arthropod vectors, including ticks, fleas, lice, triatomines, mosquitoes, tabanids, and phlebotomine sand flies. This article focuses on several aspects (etiology, transmission, distribution, prevalence, risk factors, diagnosis, control, prevention, and public health significance) of CVBDs in Brazil and discusses research gaps to be addressed in future studies. PMID:18691408

Canine vector-borne diseases in Brazil

Directory of Open Access Journals (Sweden)

Dantas-Torres Filipe

2008-08-01

Full Text Available Abstract Canine vector-borne diseases (CVBDs are highly prevalent in Brazil and represent a challenge to veterinarians and public health workers, since some diseases are of great zoonotic potential. Dogs are affected by many protozoa (e.g., Babesia vogeli, Leishmania infantum, and Trypanosoma cruzi, bacteria (e.g., Anaplasma platys and Ehrlichia canis, and helminths (e.g., Dirofilaria immitis and Dipylidium caninum that are transmitted by a diverse range of arthropod vectors, including ticks, fleas, lice, triatomines, mosquitoes, tabanids, and phlebotomine sand flies. This article focuses on several aspects (etiology, transmission, distribution, prevalence, risk factors, diagnosis, control, prevention, and public health significance of CVBDs in Brazil and discusses research gaps to be addressed in future studies.

Crowdsourcing Vector Surveillance: Using Community Knowledge and Experiences to Predict Densities and Distribution of Outdoor-Biting Mosquitoes in Rural Tanzania.

Directory of Open Access Journals (Sweden)

Stephen Peter Mwangungulu

Full Text Available Lack of reliable techniques for large-scale monitoring of disease-transmitting mosquitoes is a major public health challenge, especially where advanced geo-information systems are not regularly applicable. We tested an innovative crowd-sourcing approach, which relies simply on knowledge and experiences of residents to rapidly predict areas where disease-transmitting mosquitoes are most abundant. Guided by community-based resource persons, we mapped boundaries and major physical features in three rural Tanzanian villages. We then selected 60 community members, taught them basic map-reading skills, and offered them gridded maps of their own villages (grid size: 200m×200m so they could identify locations where they believed mosquitoes were most abundant, by ranking the grids from one (highest density to five (lowest density. The ranks were interpolated in ArcGIS-10 (ESRI-USA using inverse distance weighting (IDW method, and re-classified to depict areas people believed had high, medium and low mosquito densities. Finally, we used odor-baited mosquito traps to compare and verify actual outdoor mosquito densities in the same areas. We repeated this process for 12 months, each time with a different group of 60 residents. All entomological surveys depicted similar geographical stratification of mosquito densities in areas classified by community members as having high, medium and low vector abundance. These similarities were observed when all mosquito species were combined, and also when only malaria vectors were considered. Of the 12,412 mosquitoes caught, 60.9% (7,555 were from areas considered by community members as having high mosquito densities, 28% (3,470 from medium density areas, and 11.2% (1,387 from low density areas. This study provides evidence that we can rely on community knowledge and experiences to identify areas where mosquitoes are most abundant or least abundant, even without entomological surveys. This crowd-sourcing method could

Impacts of the creation, expansion and management of English wetlands on mosquito presence and abundance - developing strategies for future disease mitigation.

Science.gov (United States)

Medlock, Jolyon M; Vaux, Alexander G C

2015-03-03

The incidence of mosquito-borne diseases is increasing in Europe, partly due to the incursion of a number of invasive species known to be vectors of dengue and chikungunya viruses, but also due to the involvement of native species in the transmission of West Nile virus and malaria. For some of these pathogens, there is a risk of the re-emergence of vector-borne diseases that were once widespread in Europe, but declined partly due to large-scale land-drainage projects. Some mosquito species exploit container habitats as breeding sites in urban areas; an adaptation to human-made micro-habitats resulting from increased urbanisation. However, many species thrive in natural wetland ecosystems. Owing to the impacts of climate change there is an urgent need for environmental adaptation, such as the creation of new wetlands to mitigate coastal and inland flooding. In some cases, these initiatives can be coupled with environmental change strategies to protect a range of endangered flora and fauna species by enhancing and extending wetland landscapes, which may by driven by European legislation, particularly in urban areas. This paper reviews field studies conducted in England to assess the impact of newly created wetlands on mosquito colonisation in a) coastal, b) urban and c) arable reversion habitats. It also considers the impact of wetland management on mosquito populations and explores the implications of various water and vegetation management options on the range of British mosquito species. Understanding the impact of wetland creation and management strategies on mosquito prevalence and the potential risk of increasing the levels of nuisance or disease vector species will be crucial in informing health and well-being risk assessments, guiding targeted control, and anticipating the social effects of extreme weather and climate change. Although new wetlands will certainly extend aquatic habitats for mosquitoes, not all species will become a major nuisance or a vector

[Vector transmitted diseases and climate changes in Europe].

Science.gov (United States)

Rossati, Antonella; Bargiacchi, Olivia; Kroumova, Vesselina; Garavelli, Pietro Luigi

2014-09-01

The increase in temperatures recorded since the mid-nineteenth century is unprecedented in the history of mankind. The consequences of climate changes are numerous and can affect human health through direct (extreme events, natural disasters) or indirect (alteration of the ecosystem) mechanisms. Climate changes have repercussions on ecosystems, agriculture, social conditions, migration, conflicts and the transmission mode of infectious diseases. Vector-borne diseases are infections transmitted by the bite of infected arthropods such as mosquitoes, ticks, triatomines, sand flies and flies. Epidemiological cornerstones of vector-borne diseases are: the ecology and behaviour of the host, the ecology and behaviour of the vector, and the population's degree of immunity. Mosquito vectors related to human diseases mainly belong to the genus Culex, Aedes and Mansonia. Climate changes in Europe have increased the spread of new vectors, such as Aedes albopictus, and in some situations have made it possible to sustain the autochthonous transmission of some diseases (outbreak of Chukungunya virus in northern Italy in 2007, cases of dengue in the South of France and in Croatia). Despite the eradication of malaria from Europe, anopheline carriers are still present, and they may allow the transmission of the disease if the climatic conditions favour the development of the vectors and their contacts with plasmodium carriers. The tick Ixodes ricinus is a vector whose expansion has been documented both in latitude and in altitude in relation to the temperature increase; at the same time the related main viral and bacterial infections have increased. In northern Italy and Germany, the appearance of Leishmaniasis has been associated to climatic conditions that favour the development of the vector Phlebotomus papatasi and the maturation of the parasite within the vector, although the increase of cases of visceral leishmaniasis is also related to host immune factors, particularly

Ocular Manifestations of Mosquito-Transmitted Diseases.

Science.gov (United States)

Karesh, James W; Mazzoli, Robert A; Heintz, Shannon K

2018-03-01

Of the 3,548 known mosquito species, about 100 transmit human diseases. Mosquitoes are distributed globally throughout tropical and temperate regions where standing water sources are available for egg laying and the maturation of larva. Female mosquitoes require blood meals for egg production. This is the main pathway for disease transmission. Mosquitoes carry several pathogenic organisms responsible for significant ocular pathology and vision loss including West Nile, Rift Valley, chikungunya, dengue viruses, various encephalitis viruses, malarial parasites, Francisella tularensis, microfilarial parasites, including Dirofilaria, Wuchereria, and Brugia spp., and human botfly larvae. Health care providers may not be familiar with many of these mosquito-transmitted diseases or their associated ocular findings delaying diagnosis, treatment, and recovery of visual function. This article aims to provide an overview of the ocular manifestations associated with mosquito-transmitted diseases.

Climate Change and Vector Borne Diseases on NASA Langley Research Center

Science.gov (United States)

Cole, Stuart K.; DeYoung, Russell J.; Shepanek, Marc A.; Kamel, Ahmed

2014-01-01

Increasing global temperature, weather patterns with above average storm intensities, and higher sea levels have been identified as phenomena associated with global climate change. As a causal system, climate change could contribute to vector borne diseases in humans. Vectors of concern originate from the vicinity of Langley Research Center include mosquitos and ticks that transmit disease that originate regionally, nationwide, or from outside the US. Recognizing changing conditions, vector borne diseases propagate under climate change conditions, and understanding the conditions in which they may exist or propagate, presents opportunities for monitoring their progress and mitigating their potential impacts through communication, continued monitoring, and adaptation. Personnel comprise a direct and fundamental support to NASA mission success, continuous and improved understanding of climatic conditions, and the resulting consequence of disease from these conditions, helps to reduce risk in terrestrial space technologies, ground operations, and space research. This research addresses conditions which are attributed to climatic conditions which promote environmental conditions conducive to the increase of disease vectors. This investigation includes evaluation of local mosquito population count and rainfall data for statistical correlation and identification of planning recommendations unique to LaRC, other NASA Centers to assess adaptation approaches, Center-level planning strategies.

Landscape movements of Anopheles gambiae malaria vector mosquitoes in rural Gambia.

Science.gov (United States)

Thomas, Christopher J; Cross, Dónall E; Bøgh, Claus

2013-01-01

For malaria control in Africa it is crucial to characterise the dispersal of its most efficient vector, Anopheles gambiae, in order to target interventions and assess their impact spatially. Our study is, we believe, the first to present a statistical model of dispersal probability against distance from breeding habitat to human settlements for this important disease vector. We undertook post-hoc analyses of mosquito catches made in The Gambia to derive statistical dispersal functions for An. gambiae sensu lato collected in 48 villages at varying distances to alluvial larval habitat along the River Gambia. The proportion dispersing declined exponentially with distance, and we estimated that 90% of movements were within 1.7 km. Although a 'heavy-tailed' distribution is considered biologically more plausible due to active dispersal by mosquitoes seeking blood meals, there was no statistical basis for choosing it over a negative exponential distribution. Using a simple random walk model with daily survival and movements previously recorded in Burkina Faso, we were able to reproduce the dispersal probabilities observed in The Gambia. Our results provide an important quantification of the probability of An. gambiae s.l. dispersal in a rural African setting typical of many parts of the continent. However, dispersal will be landscape specific and in order to generalise to other spatial configurations of habitat and hosts it will be necessary to produce tractable models of mosquito movements for operational use. We show that simple random walk models have potential. Consequently, there is a pressing need for new empirical studies of An. gambiae survival and movements in different settings to drive this development.

Insecticide resistance in disease vectors from Mayotte: an opportunity for integrated vector management.

Science.gov (United States)

Pocquet, Nicolas; Darriet, Frédéric; Zumbo, Betty; Milesi, Pascal; Thiria, Julien; Bernard, Vincent; Toty, Céline; Labbé, Pierrick; Chandre, Fabrice

2014-07-01

Mayotte, a small island in the Indian Ocean, has been affected for many years by vector-borne diseases. Malaria, Bancroftian filariasis, dengue, chikungunya and Rift Valley fever have circulated or still circulate on the island. They are all transmitted by Culicidae mosquitoes. To limit the impact of these diseases on human health, vector control has been implemented for more than 60 years on Mayotte. In this study, we assessed the resistance levels of four major vector species (Anopheles gambiae, Culex pipiens quinquefasciatus, Aedes aegypti and Aedes albopictus) to two types of insecticides: i) the locally currently-used insecticides (organophosphates, pyrethroids) and ii) alternative molecules that are promising for vector control and come from different insecticide families (bacterial toxins or insect growth regulators). When some resistance was found to one of these insecticides, we characterized the mechanisms involved. Larval and adult bioassays were used to evaluate the level of resistance. When resistance was found, we tested for the presence of metabolic resistance through detoxifying enzyme activity assays, or for target-site mutations through molecular identification of known resistance alleles. Resistance to currently-used insecticides varied greatly between the four vector species. While no resistance to any insecticides was found in the two Aedes species, bioassays confirmed multiple resistance in Cx. p. quinquefasciatus (temephos: ~ 20 fold and deltamethrin: only 10% mortality after 24 hours). In An. gambiae, resistance was scarce: only a moderate resistance to temephos was found (~5 fold). This resistance appears to be due only to carboxyl-esterase overexpression and not to target modification. Finally, and comfortingly, none of the four species showed resistance to any of the new insecticides. The low resistance observed in Mayotte's main disease vectors is particularly interesting, because it leaves a range of tools useable by vector control

S argassum muticum-synthesized silver nanoparticles: an effective control tool against mosquito vectors and bacterial pathogens.

Science.gov (United States)

Madhiyazhagan, Pari; Murugan, Kadarkarai; Kumar, Arjunan Naresh; Nataraj, Thiyagarajan; Dinesh, Devakumar; Panneerselvam, Chellasamy; Subramaniam, Jayapal; Mahesh Kumar, Palanisamy; Suresh, Udaiyan; Roni, Mathath; Nicoletti, Marcello; Alarfaj, Abdullah A; Higuchi, Akon; Munusamy, Murugan A; Benelli, Giovanni

2015-11-01

Mosquito-borne diseases represent a deadly threat for millions of people worldwide. Furthermore, pathogens and parasites polluting water also constitute a severe plague for populations of developing countries. In this research, silver nanoparticles (AgNP) were synthesized using the aqueous extract of the seaweed Sargassum muticum. The production of AgNP was confirmed by surface plasmon resonance band illustrated in UV-vis spectrophotometry. AgNP were characterized by FTIR, SEM, EDX, and XRD analyses. AgNP were mostly spherical in shape, crystalline in nature, with face-centered cubic geometry, and mean size was 43-79 nm. Toxicity of AgNP was assessed against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. In laboratory, AgNP were highly toxic against larvae and pupae of the three mosquito species. Maximum efficacy was observed against A. stephensi larvae, with LC50 ranging from 16.156 ppm (larva I) to 28.881 ppm (pupa). In the field, a single treatment with AgNP (10 × LC50) in water storage reservoirs was effective against the three mosquito vectors, allowing complete elimination of larval populations after 72 h. In ovicidal experiments, egg hatchability was reduced by 100% after treatment with 30 ppm of AgNP. Ovideterrence assays highlighted that 10 ppm of AgNP reduced oviposition rates of more than 70% in A. aegypti, A. stephensi, and C. quinquefasciatus (OAI = -0.61, -0.63, and -0.58, respectively). Antibacterial properties of AgNP were evaluated against Bacillus subtilis, Klebsiella pneumoniae, and Salmonella typhi using the agar disk diffusion and minimum inhibitory concentration protocol. AgNP tested at 50 ppm evoked growth inhibition zones larger than 5 mm in all tested bacteria. Overall, the chance to use S. muticum-synthesized AgNP for control of mosquito vectors seems promising since they are effective at low doses and may constitute an advantageous alternative to build newer and safer mosquito control tools. This is the first

Unraveling Host-Vector-Arbovirus Interactions by Two-Gene High Resolution Melting Mosquito Bloodmeal Analysis in a Kenyan Wildlife-Livestock Interface.

Directory of Open Access Journals (Sweden)

David Omondi

Full Text Available The blood-feeding patterns of mosquitoes are directly linked to the spread of pathogens that they transmit. Efficient identification of arthropod vector bloodmeal hosts can identify the diversity of vertebrate species potentially involved in disease transmission cycles. While molecular bloodmeal analyses rely on sequencing of cytochrome b (cyt b or cytochrome oxidase 1 gene PCR products, recently developed bloodmeal host identification based on high resolution melting (HRM analyses of cyt b PCR products is more cost-effective. To resolve the diverse vertebrate hosts that mosquitoes may potentially feed on in sub-Saharan Africa, we utilized HRM profiles of both cyt b and 16S ribosomal RNA genes. Among 445 blood-fed Aedeomyia, Aedes, Anopheles, Culex, Mansonia, and Mimomyia mosquitoes from Kenya's Lake Victoria and Lake Baringo regions where many mosquito-transmitted pathogens are endemic, we identified 33 bloodmeal hosts including humans, eight domestic animal species, six peridomestic animal species and 18 wildlife species. This resolution of vertebrate host species was only possible by comparing profiles of both cyt b and 16S markers, as melting profiles of some pairs of species were similar for either marker but not both. We identified mixed bloodmeals in a Culex pipiens from Mbita that had fed on a goat and a human and in two Mansonia africana mosquitoes from Baringo that each had fed on a rodent (Arvicanthis niloticus in addition to a human or baboon. We further detected Sindbis and Bunyamwera viruses in blood-fed mosquito homogenates by Vero cell culture and RT-PCR in Culex, Aedeomyia, Anopheles and Mansonia mosquitoes from Baringo that had fed on humans and livestock. The observed mosquito feeding on both arbovirus amplifying hosts (including sheep and goats and possible arbovirus reservoirs (birds, porcupine, baboons, rodents informs arbovirus disease epidemiology and vector control strategies.

Current procedures of the integrated urban vector-mosquito control as an example in Cotonou (Benin, West Africa) and Wrocław area (Poland).

Science.gov (United States)

Rydzanicz, Katarzyna; Lonc, Elzbieta; Becker, Norbert

2009-01-01

Current strategy of Integrated Vector Management (IVM) comprises the general approach of environmentally friendly control measures. With regard to mosquitoes it includes first of all application of microbial insecticides based on Bacillus thuringiensis israelensis (Bti) and B. sphaericus (Bs) delta-endotoxins as well as the reduction of breeding habitats and natural enemy augmentation. It can be achieved thorough implementation of the interdisciplinary program, i. e., understanding of mosquito vector ecology, the appropriate vector-diseases (e. g., malariometric) measurements and training of local personnel responsible for mosquito abatement activities, as well as community involvement. Biocontrol methods as an alternative to chemical insecticides result from the sustainability development concept, growing awareness of environmental pollution and the development of insecticide-resistant strains of vector-mosquito populations in many parts of the world. Although sustainable trends are usually considered in terms of the monetary and training resources within countries, environmental concerns are actually more limiting factors for the duration of an otherwise successful vector control effort. In order to meet these new needs, increasing efforts have been made in search of and application of natural enemies, such as parasites, bacterial pathogens and predators which may control populations of insect vectors. The biological control agent based on the bacterial toxins Bti and Bs has been used in the Wrocław's University and Municipal Mosquito Control Programs since 1998. In West-Africa biocontrol appears to be an effective and safe tool to combat malaria in addition to bed-nets, residual indoor spraying and appropriate diagnosis and treatment of malaria parasites which are the major tools in the WHO Roll Back Malaria Program. IVM studies carried out 2005-2008 in Cotonou (Benin) as well those in Wrocław Irrigated Fields during the last years include the following major

Plant extracts as potential mosquito larvicides.

Science.gov (United States)

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.

Señales físico químicas involucradas en la búsqueda de hospederos y en la inducción de picadura por mosquitos Physic-chemical signals involved in host localization and induction of disease vector mosquito bites

Directory of Open Access Journals (Sweden)

José Luis Torres-Estrada

2003-12-01

Full Text Available Las hembras de los mosquitos vectores de enfermedades utilizan señales físicas y químicas para localizar su fuente de alimentación sanguínea en hospederos vertebrados. Los mosquitos zoofílicos responden preferentemente al CO2 y al octenol liberados en la respiración y excreciones, mientras que los mosquitos antropofílicos responden al ácido láctico y a una variedad de compuestos del sudor. Estos compuestos son modificados por microrganismos saprófitos de las glándulas sebáceas de la piel. Otros factores presentes en las viviendas contribuyen a la integración de microsistemas constituidos por olores característicos, que explican los diferentes niveles de atracción de mosquitos y la focalización de la transmisión del paludismo a una porción de casas en localidades de áreas endémicas. La identificación de estos atrayentes químicos y sus moléculas receptoras en mosquitos puede ser utilizada como complemento de nuevos métodos para la vigilancia epidemiológica, para atraer a los mosquitos a trampas de colecta o para incrementar su contacto con insecticidas usados en su control, así como en la manipulación genética para desviar las picaduras de los mosquitos hacia otros hospederos vertebrados.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

Assessment of Local Mosquito Species Incriminates Aedes aegypti as the Potential Vector of Zika Virus in Australia.

Directory of Open Access Journals (Sweden)

Sonja Hall-Mendelin

2016-09-01

Full Text Available Within the last 10 years Zika virus (ZIKV has caused unprecedented epidemics of human disease in the nations and territories of the western Pacific and South America, and continues to escalate in both endemic and non-endemic regions. We evaluated the vector competence of Australian mosquitoes for ZIKV to assess their potential role in virus transmission.Mosquitoes were exposed to infectious blood meals containing the prototype African ZIKV strain. After 14 days incubation at 28°C and high relative humidity, infection, dissemination and transmission rates were assessed. Infection in Culex annulirostris and Cx. sitiens could not be detected. 8% of Cx. quinquefasciatus were infected, but the virus did not disseminate in this species. Despite having infection rates > 50%, Aedes notoscriptus and Ae. vigilax did not transmit ZIKV. In contrast, Ae. aegypti had infection and transmission rates of 57% and 27%, respectively. In susceptibility trials, the virus dose required to infect 50% (ID50 of Ae. aegypti was106.4 tissue culture infectious dose50 (TCID50/mL. Additionally, a threshold viral load within the mosquito of at least 105.1 TCID50 equivalents/mL had to be reached before virus transmission occurred.We confirmed Ae. aegypti to be the most likely mosquito vector of ZIKV in Australia, although the restricted distribution of this species will limit the receptive zone to northern Queensland where this species occurs. Importantly, the role in ZIKV transmission of Culex and other Aedes spp. tested will be negligible. Despite being the implicated vector, the relatively high ID50 and need for a high titer disseminated infection in Ae. aegypti suggest that high mosquito population densities will be required to facilitate epidemic ZIKV transmission among the currently immunologically naïve human population in Australia.

Assessment of Local Mosquito Species Incriminates Aedes aegypti as the Potential Vector of Zika Virus in Australia.

Science.gov (United States)

Hall-Mendelin, Sonja; Pyke, Alyssa T; Moore, Peter R; Mackay, Ian M; McMahon, Jamie L; Ritchie, Scott A; Taylor, Carmel T; Moore, Frederick A J; van den Hurk, Andrew F

2016-09-01

Within the last 10 years Zika virus (ZIKV) has caused unprecedented epidemics of human disease in the nations and territories of the western Pacific and South America, and continues to escalate in both endemic and non-endemic regions. We evaluated the vector competence of Australian mosquitoes for ZIKV to assess their potential role in virus transmission. Mosquitoes were exposed to infectious blood meals containing the prototype African ZIKV strain. After 14 days incubation at 28°C and high relative humidity, infection, dissemination and transmission rates were assessed. Infection in Culex annulirostris and Cx. sitiens could not be detected. 8% of Cx. quinquefasciatus were infected, but the virus did not disseminate in this species. Despite having infection rates > 50%, Aedes notoscriptus and Ae. vigilax did not transmit ZIKV. In contrast, Ae. aegypti had infection and transmission rates of 57% and 27%, respectively. In susceptibility trials, the virus dose required to infect 50% (ID50) of Ae. aegypti was106.4 tissue culture infectious dose50 (TCID50)/mL. Additionally, a threshold viral load within the mosquito of at least 105.1 TCID50 equivalents/mL had to be reached before virus transmission occurred. We confirmed Ae. aegypti to be the most likely mosquito vector of ZIKV in Australia, although the restricted distribution of this species will limit the receptive zone to northern Queensland where this species occurs. Importantly, the role in ZIKV transmission of Culex and other Aedes spp. tested will be negligible. Despite being the implicated vector, the relatively high ID50 and need for a high titer disseminated infection in Ae. aegypti suggest that high mosquito population densities will be required to facilitate epidemic ZIKV transmission among the currently immunologically naïve human population in Australia.

Mitochondrial markers for molecular identification of Aedes mosquitoes (Diptera: Culicidae) involved in transmission of arboviral disease in West Africa.

Science.gov (United States)

Cook, Shelley; Diallo, Mawlouth; Sall, Amadou A; Cooper, Alan; Holmes, Edward C

2005-01-01

Correct classification of the insect vector is central to the study of arboviral disease. A simple molecular method for identification of the main vectors of the mosquito-borne viruses, dengue, yellow fever, and Rift Valley fever in Senegal, West Africa, was developed. We present a system in which the five mosquito species (Diptera: Culicidae) responsible for the majority of flaviviral disease transmission in Senegal can be reliably identified using small amounts of DNA coextracted during flaviviral screening procedures, via an easy amplification of the mitochondrial gene cytochrome oxidase c subunit I or II (COI or COII, respectively). We observed that despite very similar morphology, the two cryptic disease vector species Aedes furcifer Edwards and Aedes taylori Edwards are highly divergent at the molecular level. This sequence variation was used as a basis for the development of a polymerase chain reaction-restriction fragment-length polymorphism system for the differentiation of the two species. We also present the first investigation of the phylogeny of the culicine mosquitoes based on all COI and COII sequences currently available. There seems to be very low intraspecific variation in both genes, whereas interspecific variation is high. As a consequence, COI and COII are ideal candidates for the molecular identification of disease vectors to species level, whereas deeper divergences remain equivocal by using these genes. This system provides a new technique for the accurate identification of culicine disease vectors in West Africa and provides a basis for the expansion of such methods into the study of a range of diseases.

Some Models for Epidemics of Vector-Transmitted Diseases

OpenAIRE

Brauer, Fred; Castillo-Chavez, Carlos; Mubayi, Anuj; Towers, Sherry

2016-01-01

Vector-transmitted diseases such as dengue fever and chikungunya have been spreading rapidly in many parts of the world. The Zika virus has been known since 1947 and invaded South America in 2013. It can be transmitted not only by (mosquito) vectors but also directly through sexual contact. Zika has developed into a serious global health problem because, while most cases are asymptomatic or very light, babies born to Zika - infected mothers may develop microcephaly and other very serious birt...

Arthropod Innate Immune Systems and Vector-Borne Diseases

OpenAIRE

Baxter, Richard H. G.; Contet, Alicia; Krueger, Kathryn

2017-01-01

Arthropods, especially ticks and mosquitoes, are the vectors for a number of parasitic and viral human diseases, including malaria, sleeping sickness, Dengue, and Zika, yet arthropods show tremendous individual variation in their capacity to transmit disease. A key factor in this capacity is the group of genetically encoded immune factors that counteract infection by the pathogen. Arthropod-specific pattern recognition receptors and protease cascades detect and respond to infection. Proteins ...

Effectiveness of Mosquito Trap with Sugar Fermented Attractant to the Vector of Dengue Hemorrhagic Fever

Directory of Open Access Journals (Sweden)

Endang Puji Astuti

2011-06-01

Full Text Available Aedes aegypti is the main vector of dengue fever that is still become health problem in the world. Various control efforts has been done at several areas through chemically or naturally control. Developing mosquitoes trapping tool is an alternative method to control mosquitoes besides insecticides utilization. This laboratorium research utilize sugar fermented process to yield CO2 as one of attractan to mosquito. Production of ethanol and CO2 can be yielded from anaerob sugar fermentation proccess (without O2 by khamir Saccharomyces cerevisiae activities. The trapped mosquitoes was observed up to 48 hours exposure, the highest average of mosquito trapped is on solution treatment with yeast 1 gram (43.2% and 40 gr sugar (48.4%. The highest effectivity of trapping tool both inside or outside was on the 14th day. There were declained amount of trapped mosquitos on 16th and 18th days. This laboratorium research has described that trapping tool with sugar fermented solution were effective to control population of dengue vector.

How effective is integrated vector management against malaria and lymphatic filariasis where the diseases are transmitted by the same vector?

Directory of Open Access Journals (Sweden)

Christopher M Stone

2014-12-01

Full Text Available The opportunity to integrate vector management across multiple vector-borne diseases is particularly plausible for malaria and lymphatic filariasis (LF control where both diseases are transmitted by the same vector. To date most examples of integrated control targeting these diseases have been unanticipated consequences of malaria vector control, rather than planned strategies that aim to maximize the efficacy and take the complex ecological and biological interactions between the two diseases into account.We developed a general model of malaria and LF transmission and derived expressions for the basic reproductive number (R0 for each disease. Transmission of both diseases was most sensitive to vector mortality and biting rate. Simulating different levels of coverage of long lasting-insecticidal nets (LLINs and larval control confirms the effectiveness of these interventions for the control of both diseases. When LF was maintained near the critical density of mosquitoes, minor levels of vector control (8% coverage of LLINs or treatment of 20% of larval sites were sufficient to eliminate the disease. Malaria had a far greater R0 and required a 90% population coverage of LLINs in order to eliminate it. When the mosquito density was doubled, 36% and 58% coverage of LLINs and larval control, respectively, were required for LF elimination; and malaria elimination was possible with a combined coverage of 78% of LLINs and larval control.Despite the low level of vector control required to eliminate LF, simulations suggest that prevalence of LF will decrease at a slower rate than malaria, even at high levels of coverage. If representative of field situations, integrated management should take into account not only how malaria control can facilitate filariasis elimination, but strike a balance between the high levels of coverage of (multiple interventions required for malaria with the long duration predicted to be required for filariasis elimination.

How effective is integrated vector management against malaria and lymphatic filariasis where the diseases are transmitted by the same vector?

Science.gov (United States)

Stone, Christopher M; Lindsay, Steve W; Chitnis, Nakul

2014-12-01

The opportunity to integrate vector management across multiple vector-borne diseases is particularly plausible for malaria and lymphatic filariasis (LF) control where both diseases are transmitted by the same vector. To date most examples of integrated control targeting these diseases have been unanticipated consequences of malaria vector control, rather than planned strategies that aim to maximize the efficacy and take the complex ecological and biological interactions between the two diseases into account. We developed a general model of malaria and LF transmission and derived expressions for the basic reproductive number (R0) for each disease. Transmission of both diseases was most sensitive to vector mortality and biting rate. Simulating different levels of coverage of long lasting-insecticidal nets (LLINs) and larval control confirms the effectiveness of these interventions for the control of both diseases. When LF was maintained near the critical density of mosquitoes, minor levels of vector control (8% coverage of LLINs or treatment of 20% of larval sites) were sufficient to eliminate the disease. Malaria had a far greater R0 and required a 90% population coverage of LLINs in order to eliminate it. When the mosquito density was doubled, 36% and 58% coverage of LLINs and larval control, respectively, were required for LF elimination; and malaria elimination was possible with a combined coverage of 78% of LLINs and larval control. Despite the low level of vector control required to eliminate LF, simulations suggest that prevalence of LF will decrease at a slower rate than malaria, even at high levels of coverage. If representative of field situations, integrated management should take into account not only how malaria control can facilitate filariasis elimination, but strike a balance between the high levels of coverage of (multiple) interventions required for malaria with the long duration predicted to be required for filariasis elimination.

RNA-seq analyses of blood-induced changes in gene expression in the mosquito vector species, Aedes aegypti

Directory of Open Access Journals (Sweden)

Olson Ken E

2011-01-01

Full Text Available Abstract Background Hematophagy is a common trait of insect vectors of disease. Extensive genome-wide transcriptional changes occur in mosquitoes after blood meals, and these are related to digestive and reproductive processes, among others. Studies of these changes are expected to reveal molecular targets for novel vector control and pathogen transmission-blocking strategies. The mosquito Aedes aegypti (Diptera, Culicidae, a vector of Dengue viruses, Yellow Fever Virus (YFV and Chikungunya virus (CV, is the subject of this study to look at genome-wide changes in gene expression following a blood meal. Results Transcriptional changes that follow a blood meal in Ae. aegypti females were explored using RNA-seq technology. Over 30% of more than 18,000 investigated transcripts accumulate differentially in mosquitoes at five hours after a blood meal when compared to those fed only on sugar. Forty transcripts accumulate only in blood-fed mosquitoes. The list of regulated transcripts correlates with an enhancement of digestive activity and a suppression of environmental stimuli perception and innate immunity. The alignment of more than 65 million high-quality short reads to the Ae. aegypti reference genome permitted the refinement of the current annotation of transcript boundaries, as well as the discovery of novel transcripts, exons and splicing variants. Cis-regulatory elements (CRE and cis-regulatory modules (CRM enriched significantly at the 5'end flanking sequences of blood meal-regulated genes were identified. Conclusions This study provides the first global view of the changes in transcript accumulation elicited by a blood meal in Ae. aegypti females. This information permitted the identification of classes of potentially co-regulated genes and a description of biochemical and physiological events that occur immediately after blood feeding. The data presented here serve as a basis for novel vector control and pathogen transmission

Highly evolvable malaria vectors : The genomes of 16 Anopheles mosquitoes

NARCIS (Netherlands)

Neafsey, D. E.; Waterhouse, R. M.; Abai, M. R.; Aganezov, S. S.; Alekseyev, M. A.; Allen, J. E.; Amon, J.; Arca, B.; Arensburger, P.; Artemov, G.; Assour, L. A.; Basseri, H.; Berlin, A.; Birren, B. W.; Blandin, S. A.; Brockman, A. I.; Burkot, T. R.; Burt, A.; Chan, C. S.; Chauve, C.; Chiu, J. C.; Christensen, M.; Costantini, C.; Davidson, V. L. M.; Deligianni, E.; Dottorini, T.; Dritsou, V.; Gabriel, S. B.; Guelbeogo, W. M.; Hall, A. B.; Han, M. V.; Hlaing, T.; Hughes, D. S. T.; Jenkins, A. M.; Jiang, X.; Jungreis, I.; Kakani, E. G.; Kamali, M.; Kemppainen, P.; Kennedy, R. C.; Kirmitzoglou, I. K.; Koekemoer, L. L.; Laban, N.; Langridge, N.; Lawniczak, M. K. N.; Lirakis, M.; Lobo, N. F.; Lowy, E.; Maccallum, R. M.; Mao, C.; Maslen, G.; Mbogo, C.; Mccarthy, J.; Michel, K.; Mitchell, S. N.; Moore, W.; Murphy, K. A.; Naumenko, A. N.; Nolan, T.; Novoa, E. M.; O'loughlin, S.; Oringanje, C.; Oshaghi, M. A.; Pakpour, N.; Papathanos, P. A.; Peery, A. N.; Povelones, M.; Prakash, A.; Price, D. P.; Rajaraman, A.; Reimer, L. J.; Rinker, D. C.; Rokas, A.; Russell, T. L.; Sagnon, N.; Sharakhova, M. V.; Shea, T.; Simao, F. A.; Simard, F.; Slotman, M. A.; Somboon, P.; Stegniy, V.; Struchiner, C. J.; Thomas, G. W. C.; Tojo, M.; Topalis, P.; Tubio, J. M. C.; Unger, M. F.; Vontas, J.; Walton, C.; Wilding, C. S.; Willis, J. H.; Wu, Y.-c.; Yan, G.; Zdobnov, E. M.; Zhou, X.; Catteruccia, F.; Christophides, G. K.; Collins, F. H.; Cornman, R. S.; Crisanti, A.; Donnelly, M. J.; Emrich, S. J.; Fontaine, M. C.; Gelbart, W.; Hahn, M. W.; Hansen, I. A.; Howell, P. I.; Kafatos, F. C.; Kellis, M.; Lawson, D.; Louis, C.; Luckhart, S.; Muskavitch, M. A. T.; Ribeiro, J. M.; Riehle, M. A.; Sharakhov, I. V.; Tu, Z.; Zwiebel, L. J.; Besansky, N. J.

2015-01-01

Variation in vectorial capacity for human malaria among Anopheles mosquito species is determined by many factors, including behavior, immunity, and life history. To investigate the genomic basis of vectorial capacity and explore new avenues for vector control, we sequenced the genomes of 16

Predictive modeling of mosquito abundance and dengue transmission in Kenya

Science.gov (United States)

Caldwell, J.; Krystosik, A.; Mutuku, F.; Ndenga, B.; LaBeaud, D.; Mordecai, E.

2017-12-01

Approximately 390 million people are exposed to dengue virus every year, and with no widely available treatments or vaccines, predictive models of disease risk are valuable tools for vector control and disease prevention. The aim of this study was to modify and improve climate-driven predictive models of dengue vector abundance (Aedes spp. mosquitoes) and viral transmission to people in Kenya. We simulated disease transmission using a temperature-driven mechanistic model and compared model predictions with vector trap data for larvae, pupae, and adult mosquitoes collected between 2014 and 2017 at four sites across urban and rural villages in Kenya. We tested predictive capacity of our models using four temperature measurements (minimum, maximum, range, and anomalies) across daily, weekly, and monthly time scales. Our results indicate seasonal temperature variation is a key driving factor of Aedes mosquito abundance and disease transmission. These models can help vector control programs target specific locations and times when vectors are likely to be present, and can be modified for other Aedes-transmitted diseases and arboviral endemic regions around the world.

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

Science.gov (United States)

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.

Review of insecticide resistance and behavioral avoidance of vectors of human diseases in Thailand

Science.gov (United States)

2013-01-01

Physiological resistance and behavioral responses of mosquito vectors to insecticides are critical aspects of the chemical-based disease control equation. The complex interaction between lethal, sub-lethal and excitation/repellent ('excito-repellent’) properties of chemicals is typically overlooked in vector management and control programs. The development of “physiological” resistance, metabolic and/or target site modifications, to insecticides has been well documented in many insect groups and disease vectors around the world. In Thailand, resistance in many mosquito populations has developed to all three classes of insecticidal active ingredients currently used for vector control with a majority being synthetic-derived pyrethroids. Evidence of low-grade insecticide resistance requires immediate countermeasures to mitigate further intensification and spread of the genetic mechanisms responsible for resistance. This can take the form of rotation of a different class of chemical, addition of a synergist, mixtures of chemicals or concurrent mosaic application of different classes of chemicals. From the gathered evidence, the distribution and degree of physiological resistance has been restricted in specific areas of Thailand in spite of long-term use of chemicals to control insect pests and disease vectors throughout the country. Most surprisingly, there have been no reported cases of pyrethroid resistance in anopheline populations in the country from 2000 to 2011. The precise reasons for this are unclear but we assume that behavioral avoidance to insecticides may play a significant role in reducing the selection pressure and thus occurrence and spread of insecticide resistance. The review herein provides information regarding the status of physiological resistance and behavioral avoidance of the primary mosquito vectors of human diseases to insecticides in Thailand from 2000 to 2011. PMID:24294938

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

Science.gov (United States)

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.

Mosquitos vetores potenciais de dirofilariose canina na Região Nordeste do Brasil Mosquitoes potential vectors of canine heartworm in the Northeast Region from Brazil

Directory of Open Access Journals (Sweden)

Silvia MM Ahid

1999-12-01

Full Text Available INTRODUÇÃO: Em alguns bairros costeiros de São Luís, Maranhão, a prevalência da dirofilariose chega a mais de 40% entre os cães domiciliados. Porém, desconhecem-se os vetores naturais, tanto lá quanto no resto do Nordeste do país. O objetivo do estudo foi identificar os prováveis vetores dessa parasitose. MÉTODOS: Realizaram-se coletas mensais de mosquitos em um bairro costeiro de São Luís, MA, de março de 1996 a maio de 1997, no peridomicílio, tendo cão e homem como iscas. Os mosquitos foram dissecados para a pesquisa de larvas da Dirofilaria immitis. RESULTADOS: Coletaram-se 1.738 mosquitos de 11 espécies. Culex quinquefasciatus, capturada todos os meses, porém menos freqüente na estação chuvosa, correspondeu a 54,5% do total, seguido de Aedes albopictus (20,3%, Aedes taeniorhynchus e Aedes scapularis (ambos 11%. Larvas de D.immitis foram encontradas em 0,1% dos Cx. quinquefasciatus e 0,5% dos Ae. taeniorhynchus. CONCLUSÕES: Ae. taeniorhynchus e Cx. quinquefasciatus foram considerados vetores potenciais da dirofilariose em São Luís. A importância local de Cx. quinquefasciatus como transmissor primário da D. immitis necessita ser melhor avaliada.INTRODUCTION: In some coastal districts of São Luís, capital of the state of Maranhão, Brazil, the prevalence of Dirofilaria immitis is more than 40% in house dogs. Natural potential vectors, as found in other areas of Northeastern Brazil, are unknown. The aim of this study was to identify probable vectors of the disease. METHODS: Mosquito catches were performed at a coastal, district Olho d'Água, in S. Luís, to look for local potential vectors. Captures were carried out monthly, from March 1996 to May 1997, outdoors, having a man and a dog as baits. Mosquitoes were dissected for D. immitis larvae. RESULTS: A total of 1,738 mosquitoes belonging to 11 species were collected. Culex quinquefasciatus, the only species collected every month, was more frequently in the dry

The fog of war: Why the environmental crusade for anadromous fish species in California could disarm the State’s local vector control districts in their war against mosquitoes

Directory of Open Access Journals (Sweden)

Stephen M. Siptroth

2011-12-01

Full Text Available In California, local mosquito and vector control districts have successfully controlled mosquito and vector-borne diseases by improving drainage patterns and applying pesticides. The Bay-Delta Conservation Plan, which is a proposed habitat conservation plan for the Sacramento-San Joaquin Bay-Delta estuary, proposes to add over 70,000 acres of habitat in the Delta to improve conditions for threatened and endangered aquatic and terrestrial species. This habitat could also be a suitable mosquito breeding habitat, which will be located in close proximity to urban and suburban communities. Wetland management practices and continued pesticide applications in the Delta could mitigate the effects of a new mosquito breeding habitat. Recent legal developments, however, require districts to obtain and comply with Clean Water Act permits, which restrict the application of pesticides in or near waters of the United States. Moreover, the U.S. Environmental Protection Agency has taken the first step in a rulemaking process that could further limit or prohibit the use of certain vector control pesticides in the Delta. In the near term and until less harmful methods for mosquito control are available, local vector control districts’ application of mosquito control pesticides should be exempt from Clean Water Act permit requirements.

Protection against mosquito vectors Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus using a novel insect repellent, ethyl anthranilate.

Science.gov (United States)

Islam, Johirul; Zaman, Kamaruz; Tyagi, Varun; Duarah, Sanjukta; Dhiman, Sunil; Chattopadhyay, Pronobesh

2017-10-01

Growing concern on the application of synthetic mosquito repellents in the recent years has instigated the identification and development of better alternatives to control different mosquito-borne diseases. In view of above, present investigation evaluates the repellent activity of ethyl anthranilate (EA), a non-toxic, FDA approved volatile food additive against three known mosquito vectors namely, Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus under laboratory conditions following standard protocols. Three concentration levels (2%, 5% and 10% w/v) of EA were tested against all the three selected mosquito species employing K & D module and arm-in-cage method to determine the effective dose (ED 50 ) and complete protection time (CPT), respectively. The repellent activity of EA was further investigated by modified arm-in-cage method to determine the protection over extended spatial ranges against all mosquito species. All behavioural situations were compared with the well-documented repellent N,N-diethylphenyl acetamide (DEPA) as a positive control. The findings demonstrated that EA exhibited significant repellent activity against all the three mosquitoes species. The ED 50 values of EA, against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus were found to be 0.96%, 5.4% and 3.6% w/v, respectively. At the concentration of 10% w/v, it provided CPTs of 60, 60 and 30min, respectively, against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus mosquitoes. Again in spatial repellency evaluation, EA was found to be extremely effective in repelling all the three tested species of mosquitoes. Ethyl anthranilate provided comparable results to standard repellent DEPA during the study. Results have concluded that the currently evaluated chemical, EA has potential repellent activity against some well established mosquito vectors. The study emphasizes that repellent activity of EA could be exploited for developing effective, eco

Host feeding pattern of Japanese encephalitis virus vector mosquitoes (Diptera: Culicidae) from Kuttanadu, Kerala, India.

Science.gov (United States)

Philip Samuel, P; Arunachalam, N; Hiriyan, J; Tyagi, B K

2008-09-01

Identification of blood meals of vector mosquitoes is an important tool in the epidemiological investigations of vector-borne diseases. The blood meals of three mosquito species involved in the transmission of Japanese encephalitis virus (JEV) from the Kuttanadu area, Kerala, were determined using the agarose gel diffusion technique. A total of 4959 blood smears belonging to Culex (Culex) tritaeniorhynchus Giles (3273), Cx. (Culex) gelidus Theobald (64), Mansonia (Mnd.) indiana Edwards (735) ,and Ma. (Mnd.) uniformis (Theobald) (887) were tested. Cx. tritaeniorhynchus had predominantly fed on bovids (46.4%), and a good proportion (29%) had fed on more than one host. Cx. tritaeniorhynchus was highly zoophagic, and human feeding accounted for only 1.5% of those individuals successfully tested. Cx. gelidus showed bovid feeding at 36% and pig feeding at 12.5%. The test results showed 42.3% Ma. indiana and 12.2% Ma. uniformis had fed on humans. Multiple feeding was observed in Ma. indiana and Ma. uniformis, and most of the double feedings were from bovids and ovids (7.9 and 20.1%, respectively). Pig feeding accounted for 4.8% of the feedings by Cx. tritaeniorhynchus, 5.3% of Ma. indiana, and 6.4% of Ma. uniformis. This study is significant because of the role played by these mosquitoes in the transmission of JEV in the Kuttanadu area of Kerala, India.

Best Practices for Preventing Vector-Borne Diseases in Dogs and Humans.

Science.gov (United States)

Dantas-Torres, Filipe; Otranto, Domenico

2016-01-01

Vector-borne diseases constitute a diversified group of illnesses, which are caused by a multitude of pathogens transmitted by arthropod vectors, such as mosquitoes, fleas, ticks, and sand flies. Proper management of these diseases is important from both human and veterinary medicine standpoints, given that many of these pathogens are transmissible to humans and dogs, which often live in close contact. In this review, we summarize the most important vector-borne diseases of dogs and humans and the best practices for their prevention. The control of these diseases would ultimately improve animal and human health and wellbeing, particularly in developing countries in the tropics, where the risk of these diseases is high and access to health care is poor. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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.

Aedes-Borne Virus-Mosquito Interactions: Mass Spectrometry Strategies and Findings.

Science.gov (United States)

Pando-Robles, Victoria; Batista, Cesar V

2017-06-01

Aedes-borne viruses are responsible for high-impact neglected tropical diseases and unpredictable outbreaks such as the ongoing Zika epidemics. Aedes mosquitoes spread different arboviruses such as Dengue virus (DENV), Chikungunya virus (CHIKV), and Zika virus, among others, and are responsible for the continuous emergence and reemergence of these pathogens. These viruses have complex transmission cycles that include two hosts, namely the Aedes mosquito as a vector and susceptible vertebrate hosts. Human infection with arboviruses causes diseases that range from subclinical or mild to febrile diseases, encephalitis, and hemorrhagic fever. Infected mosquitoes do not show detectable signs of disease, even though the virus maintains a lifelong persistent infection. The infection of the Aedes mosquito by viruses involves a molecular crosstalk between cell and viral proteins. An understanding of how mosquito vectors and viruses interact is of fundamental interest, and it also offers novel perspectives for disease control. In recent years, mass spectrometry (MS)-based strategies in combination with bioinformatics have been successfully applied to identify and quantify global changes in cellular proteins, lipids, peptides, and metabolites in response to viral infection. Although the information about proteomics in the Aedes mosquito is limited, the information that has been reported can set up the basis for future studies. This review reflects how MS-based approaches have extended our understanding of Aedes mosquito biology and the development of DENV and CHIKV infection in the vector. Finally, this review discusses future challenges in the field.

Altered vector competence in an experimental mosquito-mouse transmission model of Zika infection.

Directory of Open Access Journals (Sweden)

Ryuta Uraki

2018-03-01

Full Text Available Few animal models of Zika virus (ZIKV infection have incorporated arthropod-borne transmission. Here, we establish an Aedes aegypti mosquito model of ZIKV infection of mice, and demonstrate altered vector competency among three strains, (Orlando, ORL, Ho Chi Minh, HCM, and Patilas, PAT. All strains acquired ZIKV in their midguts after a blood meal from infected mice, but ZIKV transmission only occurred in mice fed upon by HCM, and to a lesser extent PAT, but not ORL, mosquitoes. This defect in transmission from ORL or PAT mosquitoes was overcome by intrathoracic injection of ZIKV into mosquito. Genetic analysis revealed significant diversity among these strains, suggesting a genetic basis for differences in ability for mosquito strains to transmit ZIKV. The intrathoracic injection mosquito-mouse transmission model is critical to understanding the influence of mosquitoes on ZIKV transmission, infectivity and pathogenesis in the vertebrate host, and represents a natural transmission route for testing vaccines and therapeutics.

Rift Valley fever potential mosquito vectors and their infection status ...

African Journals Online (AJOL)

important entomological features for the identification of potential high risk areas for RVF occurrence, which can provide guidance in the design of appropriate prevention and control measures. The findings of this study have shown that the abundance and diversity of potential. RVF mosquito vectors vary between the study ...

Relative Abundance of Adult Mosquitoes in University of Abuja Main ...

African Journals Online (AJOL)

Relative Abundance of Adult Mosquitoes in University of Abuja Main ... relative abundance of adult mosquitoes in four selected sites in University of Abuja ... These results indicated that vectors of mosquito-borne diseases are breeding in the ...

A push-pull system to reduce house entry of malaria mosquitoes

NARCIS (Netherlands)

Menger, D.J.; Otieno, B.; Rijk, de M.; Mukabana, W.R.; Loon, van J.J.A.; Takken, W.

2014-01-01

Background. Mosquitoes are the dominant vectors of pathogens that cause infectious diseases such as malaria, dengue, yellow fever and filariasis. Current vector control strategies often rely on the use of pyrethroids against which mosquitoes are increasingly developing resistance. Here, a push-pull

Facile fabrication of eco-friendly nano-mosquitocides: Biophysical characterization and effectiveness on neglected tropical mosquito vectors.

Science.gov (United States)

Govindarajan, Marimuthu; Hoti, S L; Benelli, Giovanni

2016-12-01

Mosquito (Diptera: Culicidae) vectors are solely responsible for transmitting important diseases such as malaria, dengue, chikungunya, Japanese encephalitis, lymphatic filariasis and Zika virus. Eco-friendly control tools of Culicidae vectors are a priority. In this study, we proposed a facile fabrication process of poly-disperse and stable silver nanoparticles (Ag NPs) using a cheap leaf extract of Ichnocarpus frutescens (Apocyanaceae). Bio-reduced Ag NPs were characterized by UV-vis spectrophotometry, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The acute toxicity of I. frutescens leaf extract and green-synthesized Ag NPs was evaluated against larvae of the malaria vector Anopheles subpictus, the dengue vector Aedes albopictus and the Japanese encephalitis vector Culex tritaeniorhynchus. Compared to the leaf aqueous extract, Ag NPs showed higher toxicity against A. subpictus, A. albopictus, and C. tritaeniorhynchus with LC 50 values of 14.22, 15.84 and 17.26μg/mL, respectively. Ag NPs were found safer to non-target mosquito predators Anisops bouvieri, Diplonychus indicus and Gambusia affinis, with LC 50 values ranging from 636.61 to 2098.61μg/mL. Overall, this research firstly shed light on the mosquitocidal potential of I. frutescens, a potential bio-resource for rapid, cheap and effective synthesis of poly-disperse and highly stable silver nanocrystals. Copyright © 2016 Elsevier Inc. All rights reserved.

Association of Climatic Variability, Vector Population and Malarial Disease in District of Visakhapatnam, India: A Modeling and Prediction Analysis.

Science.gov (United States)

Srimath-Tirumula-Peddinti, Ravi Chandra Pavan Kumar; Neelapu, Nageswara Rao Reddy; Sidagam, Naresh

2015-01-01

Malarial incidence, severity, dynamics and distribution of malaria are strongly determined by climatic factors, i.e., temperature, precipitation, and relative humidity. The objectives of the current study were to analyse and model the relationships among climate, vector and malaria disease in district of Visakhapatnam, India to understand malaria transmission mechanism (MTM). Epidemiological, vector and climate data were analysed for the years 2005 to 2011 in Visakhapatnam to understand the magnitude, trends and seasonal patterns of the malarial disease. Statistical software MINITAB ver. 14 was used for performing correlation, linear and multiple regression analysis. Perennial malaria disease incidence and mosquito population was observed in the district of Visakhapatnam with peaks in seasons. All the climatic variables have a significant influence on disease incidence as well as on mosquito populations. Correlation coefficient analysis, seasonal index and seasonal analysis demonstrated significant relationships among climatic factors, mosquito population and malaria disease incidence in the district of Visakhapatnam, India. Multiple regression and ARIMA (I) models are best suited models for modeling and prediction of disease incidences and mosquito population. Predicted values of average temperature, mosquito population and malarial cases increased along with the year. Developed MTM algorithm observed a major MTM cycle following the June to August rains and occurring between June to September and minor MTM cycles following March to April rains and occurring between March to April in the district of Visakhapatnam. Fluctuations in climatic factors favored an increase in mosquito populations and thereby increasing the number of malarial cases. Rainfall, temperatures (20°C to 33°C) and humidity (66% to 81%) maintained a warmer, wetter climate for mosquito growth, parasite development and malaria transmission. Changes in climatic factors influence malaria directly by

Species composition and fauna distribution of mosquitoes (Diptera: Culicidae and its importance for vector-borne diseases in a rural area of Central Western - Mato Grosso, Brazil

Directory of Open Access Journals (Sweden)

Fábio Alexandre Leal-Santos

2017-08-01

Full Text Available Abstract. This study describes ecological data obtained in a rural area in the State of Mato Grosso, including the insects belonging to the family Culicidae, especially those framed as potential vectors of tropical diseases. In 2015, we collected adult mosquitoes in fragments of forest in a rural area located in Mato Grosso Central West of Brazil. We captured 18,256 mosquitoes of the sub-families Culicinae and Anophelinae and have identified 34 species belonging to 12 genera: Aedes (1 species, Anopheles (8 species, Coquillettidia (1 species, Haemagogus (1 species, Culex (5 species, Psorophora  (5 species, Ochlerotatus (4 species, Deinocerites (1 species,  Mansonia (4 species, Sabethes (2 species, Limatus (1 species, Wyeomyia (1 species. The family Culicidae presented high richness and abundance, established by diversity indexes (Margalef α =3.26; Shannon H' = 2.09; Simpson D = 0.19 with dominance of the species Anopheles (Nyssorhyncus darlingi Root (89.8%. This species has considerable epidemiological value, considered the main vector of malaria in Mato Grosso. Many species of mosquitoes are vectors of pathogens that cause disease in humans and domestic animals, transmitting pathogens including viruses (arboviruses, filaria worms (helminths and protozoa. Composição de espécies e distribuição da fauna de mosquitos (Diptera: Culicidae e sua importância para doenças transmitidas por vetores em uma área rural do centro-ocidental - Mato Grosso, Brasil Resumo. Este estudo descreve dados ecológicos de uma área rural do Estado de Mato Grosso e dos insetos da família Culicidae especialmente aqueles enquadrados como vetores potenciais de doenças tropicais. Em 2015, coletamos mosquitos adultos em fragmentos de floresta em localidades de áreas rurais no Mato Grosso região Centro Oeste do Brasil. Foram capturados 18.256 exemplares alados de mosquitos das subfamílias Culicinae e Anophelinae e identificadas 34 espécies pertencentes a 12 g

Control of Malaria Vector Mosquitoes by Insecticide-Treated Combinations of Window Screens and Eave Baffles.

Science.gov (United States)

Killeen, Gerry F; Masalu, John P; Chinula, Dingani; Fotakis, Emmanouil A; Kavishe, Deogratius R; Malone, David; Okumu, Fredros

2017-05-01

We assessed window screens and eave baffles (WSEBs), which enable mosquitoes to enter but not exit houses, as an alternative to indoor residual spraying (IRS) for malaria vector control. WSEBs treated with water, the pyrethroid lambda-cyhalothrin, or the organophosphate pirimiphos-methyl, with and without a binding agent for increasing insecticide persistence on netting, were compared with IRS in experimental huts. Compared with IRS containing the same insecticide, WSEBs killed similar proportions of Anopheles funestus mosquitoes that were resistant to pyrethroids, carbamates and organochlorines and greater proportions of pyrethroid-resistant, early exiting An. arabiensis mosquitoes. WSEBs with pirimiphos-methyl killed greater proportions of both vectors than lambda-cyhalothrin or lambda-cyhalothrin plus pirimiphos-methyl and were equally efficacious when combined with binding agent. WSEBs required far less insecticide than IRS, and binding agents might enhance durability. WSEBs might enable affordable deployment of insecticide combinations to mitigate against physiologic insecticide resistance and improve control of behaviorally resistant, early exiting vectors.

GLOBE Observer Mosquito Habitat Mapper: Geoscience and Public Health Connections

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Plant-mediated synthesis of nanoparticles: A newer and safer tool against mosquito-borne diseases?

Directory of Open Access Journals (Sweden)

Giovanni Benelli

2016-04-01

Full Text Available Prevention and control of mosquito-borne diseases is a key challenge of huge public health importance. Plant-mediated synthesis of nanoparticles has recently gained attention as a cheap, rapid and eco-friendly method to control mosquito vector populations, with special reference to young instars. Furthermore, plant-fabricated nanoparticles have been successfully employed as dengue virus growth inhibitors. In this Editorial, parasitologists, entomologists and researchers in drug nanosynthesis are encouraged to deal with a number of crucial challenges of public health importance.

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

OpenAIRE

Walter J. Tabachnick

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...

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

Science.gov (United States)

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

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

Directory of Open Access Journals (Sweden)

Walter J. Tabachnick

2016-09-01

Full Text Available 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.

First report of the infection of insecticide-resistant malaria vector mosquitoes with an entomopathogenic fungus under field conditions

NARCIS (Netherlands)

Howard, Annabel F. V.; N'Guessan, Raphael; Koenraadt, Constantianus J. M.; Asidi, Alex; Farenhorst, Marit; Akogbéto, Martin; Knols, Bart G. J.; Takken, Willem

2011-01-01

Insecticide-resistant mosquitoes are compromising the ability of current mosquito control tools to control malaria vectors. A proposed new approach for mosquito control is to use entomopathogenic fungi. These fungi have been shown to be lethal to both insecticide-susceptible and

Aquatic insect predators and mosquito control.

Science.gov (United States)

Shaalan, Essam Abdel-Salam; Canyon, Deon V

2009-12-01

Mosquitoes are serious biting pests and obligate vectors of many vertebrate pathogens. Their immature larval and pupal life stages are a common feature in most tropical and many temperate water bodies and often form a significant proportion of the biomass. Control strategies rely primarily on the use of larvicides and environmental modification to reduce recruitment and adulticides during periods of disease transmission. Larvicides are usually chemical but can involve biological toxins, agents or organisms. The use of insect predators in mosquito control has been exploited in a limited fashion and there is much room for further investigation and implementation. Insects that are recognized as having predatorial capacity with regard to mosquito prey have been identified in the Orders Odonata, Coleoptera, Diptera (primarily aquatic predators), and Hemiptera (primarily surface predators). Although their capacity is affected by certain biological and physical factors, they could play a major role in mosquito control. Furthermore, better understanding for the mosquitoes-predators relationship(s) could probably lead to satisfactory reduction of mosquito-borne diseases by utilizing either these predators in control programs, for instance biological and/or integrated control, or their kairomones as mosquitoes' ovipoisting repellents. This review covers the predation of different insect species on mosquito larvae, predator-prey-habitat relationships, co-habitation developmental issues, survival and abundance, oviposition avoidance, predatorial capacity and integrated vector control.

Using green fluorescent malaria parasites to screen for permissive vector mosquitoes

Directory of Open Access Journals (Sweden)

Martin Beatrice

2006-03-01

Full Text Available Abstract Background The Plasmodium species that infect rodents, particularly Plasmodium berghei and Plasmodium yoelii, are useful to investigate host-parasite interactions. The mosquito species that act as vectors of human plasmodia in South East Asia, Africa and South America show different susceptibilities to infection by rodent Plasmodium species. P. berghei and P. yoelii infect both Anopheles gambiae and Anopheles stephensi, which are found mainly in Africa and Asia, respectively. However, it was reported that P. yoelii can infect the South American mosquito, Anopheles albimanus, while P. berghei cannot. Methods P. berghei lines that express the green fluorescent protein were used to screen for mosquitoes that are susceptible to infection by P. berghei. Live mosquitoes were examined and screened for the presence of a fluorescent signal in the abdomen. Infected mosquitoes were then examined by time-lapse microscopy to reveal the dynamic behaviour of sporozoites in haemolymph and extracted salivary glands. Results A single fluorescent oocyst can be detected in live mosquitoes and P. berghei can infect A. albimanus. As in other mosquitoes, P. berghei sporozoites can float through the haemolymph and invade A. albimanus salivary glands and they are infectious in mice after subcutaneous injection. Conclusion Fluorescent Plasmodium parasites can be used to rapidly screen susceptible mosquitoes. These results open the way to develop a laboratory model in countries where importation of A. gambiae and A. stephensi is not allowed.

Simplified models of vector control impact upon malaria transmission by zoophagic mosquitoes.

Directory of Open Access Journals (Sweden)

Samson S Kiware

Full Text Available BACKGROUND: High coverage of personal protection measures that kill mosquitoes dramatically reduce malaria transmission where vector populations depend upon human blood. However, most primary malaria vectors outside of sub-Saharan Africa can be classified as "very zoophagic," meaning they feed occasionally (<10% of blood meals upon humans, so personal protection interventions have negligible impact upon their survival. METHODS AND FINDINGS: We extended a published malaria transmission model to examine the relationship between transmission, control, and the baseline proportion of bloodmeals obtained from humans (human blood index. The lower limit of the human blood index enables derivation of simplified models for zoophagic vectors that (1 Rely on only three field-measurable parameters. (2 Predict immediate and delayed (with and without assuming reduced human infectivity, respectively impacts of personal protection measures upon transmission. (3 Illustrate how appreciable indirect communal-level protection for non-users can be accrued through direct personal protection of users. (4 Suggest the coverage and efficacy thresholds required to attain epidemiological impact. The findings suggest that immediate, indirect, community-wide protection of users and non-users alike may linearly relate to the efficacy of a user's direct personal protection, regardless of whether that is achieved by killing or repelling mosquitoes. High protective coverage and efficacy (≥80% are important to achieve epidemiologically meaningful impact. Non-users are indirectly protected because the two most common species of human malaria are strict anthroponoses. Therefore, the small proportion of mosquitoes that are killed or diverted while attacking humans can represent a large proportion of those actually transmitting malaria. CONCLUSIONS: Simplified models of malaria transmission by very zoophagic vectors may be used by control practitioners to predict intervention impact

Replacing a native Wolbachia with a novel strain results in an increase in endosymbiont load and resistance to dengue virus in a mosquito vector.

Directory of Open Access Journals (Sweden)

Guowu Bian

Full Text Available Wolbachia is a maternally transmitted endosymbiotic bacterium that is estimated to infect up to 65% of insect species. The ability of Wolbachia to both induce pathogen interference and spread into mosquito vector populations makes it possible to develop Wolbachia as a biological control agent for vector-borne disease control. Although Wolbachia induces resistance to dengue virus (DENV, filarial worms, and Plasmodium in mosquitoes, species like Aedes polynesiensis and Aedes albopictus, which carry native Wolbachia infections, are able to transmit dengue and filariasis. In a previous study, the native wPolA in Ae. polynesiensis was replaced with wAlbB from Ae. albopictus, and resulted in the generation of the transinfected "MTB" strain with low susceptibility for filarial worms. In this study, we compare the dynamics of DENV serotype 2 (DENV-2 within the wild type "APM" strain and the MTB strain of Ae. polynesiensis by measuring viral infection in the mosquito whole body, midgut, head, and saliva at different time points post infection. The results show that wAlbB can induce a strong resistance to DENV-2 in the MTB mosquito. Evidence also supports that this resistance is related to a dramatic increase in Wolbachia density in the MTB's somatic tissues, including the midgut and salivary gland. Our results suggests that replacement of a native Wolbachia with a novel infection could serve as a strategy for developing a Wolbachia-based approach to target naturally infected insects for vector-borne disease control.

First report of the infection of insecticide-resistant malaria vector mosquitoes with an entomopathogenic fungus under field conditions

NARCIS (Netherlands)

Howard, A.F.V.; N'Guessan, R.; Koenraadt, C.J.M.; Asidi, A.; Farenhorst, M.; Akogbeto, M.; Knols, B.G.J.; Takken, W.

2011-01-01

Background: Insecticide-resistant mosquitoes are compromising the ability of current mosquito control tools to control malaria vectors. A proposed new approach for mosquito control is to use entomopathogenic fungi. These fungi have been shown to be lethal to both insecticide-susceptible and

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

Science.gov (United States)

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

2017-08-29

Mosquitoes are vectors for many diseases such as malaria. Insecticide-treated bed nets and indoor residual spraying of insecticides are the principal malaria vector control tools used to prevent malaria in the tropics. Other interventions aim at reducing man-vector contact. For example, house screening provides additive or synergistic effects to other implemented measures. We used commercial screen materials made of polyester, polyethylene or polypropylene to design novel mosquito screens that provide remarkable additional benefits to those commonly used in house screening. The novel design is based on a double screen setup made of a screen with 3D geometric structures parallel to a commercial mosquito screen creating a trap between the two screens. Owing to the design of the 3D screen, mosquitoes can penetrate the 3D screen from one side but cannot return through the other side, making it a unidirectional mosquito screen. Therefore, the mosquitoes are trapped inside the double screen system. The permissiveness of both sides of the 3D screens for mosquitoes to pass through was tested in a wind tunnel using the insectary strain of Anopheles stephensi. Among twenty-five tested 3D screen designs, three designs from the cone, prism, or cylinder design groups were the most efficient in acting as unidirectional mosquito screens. The three cone-, prism-, and cylinder-based screens allowed, on average, 92, 75 and 64% of Anopheles stephensi mosquitoes released into the wind tunnel to penetrate the permissive side and 0, 0 and 6% of mosquitoes to escape through the non-permissive side, respectively. A cone-based 3D screen fulfilled the study objective. It allowed capturing 92% of mosquitoes within the double screen setup inside the wind tunnel and blocked 100% from escaping. Thus, the cone-based screen effectively acted as a unidirectional mosquito screen. This 3D screen-based trap design could therefore be used in house screening as a means of avoiding infective bites and

Relevancia del mosquito tigre (Aedes Albopictus) como vector de enfermedades.

OpenAIRE

Blasco Rivera, Cristina

2017-01-01

El mosquito tigre (Ae. Albopictus) es uno de los vectores de las enfermedades causadas por arbovirus, siendo actualmente, la especie vectorial más invasiva del mundo. Se introdujo en Europa en 1979 localizándose en España por primera vez en agosto de 2004 en San Cugat del Vallés en Barcelona, desde donde no ha dejado de extenderse. Es vector del virus del dengue, virus del chikungunya, virus Zika y virus de la fiebre amarilla. El objetivo principal de este Trabajo de Fin de Grado será realiza...

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

Science.gov (United States)

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.

Field evaluation of two commercial mosquito traps baited with different attractants and colored lights for malaria vector surveillance in Thailand.

Science.gov (United States)

Ponlawat, Alongkot; Khongtak, Patcharee; Jaichapor, Boonsong; Pongsiri, Arissara; Evans, Brian P

2017-08-07

Sampling for adult mosquito populations is a means of evaluating the efficacy of vector control operations. The goal of this study was to evaluate and identify the most efficacious mosquito traps and combinations of attractants for malaria vector surveillance along the Thai-Myanmar border. In the first part of the study, the BG-Sentinel™ Trap (BGS Trap) and Centers for Disease Control and Prevention miniature light trap (CDC LT) baited with different attractants (BG-lure® and CO 2 ) were evaluated using a Latin square experimental design. The six configurations were BGS Trap with BG-lure, BGS Trap with BG-lure plus CO 2 , BGS Trap with CO 2 , CDC LT with BG-lure, CDC LT with BG lure plus CO 2 , and CDC LT with CO 2 . The second half of the study evaluated the impact of light color on malaria vector collections. Colors included the incandescent bulb, ultraviolet (UV) light-emitting diode (LED), green light stick, red light stick, green LED, and red LED. A total of 8638 mosquitoes consisting of 42 species were captured over 708 trap-nights. The trap types, attractants, and colored lights affected numbers of female anopheline and Anopheles minimus collected (GLM, P surveillance when baited with CO 2 and the BG-lure in combination and can be effectively used as the new gold standard technique for collecting malaria vectors in Thailand.

Heartworm disease (Dirofilaria immitis and their vectors in Europe. New distribution trends.

Directory of Open Access Journals (Sweden)

Rodrigo eMorchón

2012-06-01

Full Text Available Cardiopulmonary dirofilariasis is a cosmopolitan disease caused by Dirofilaria immitis, which affects mainly canids and felids. Moreover, it causes zoonotic infections, producing pulmonary dirofilariasis in humans. Heartworm disease is a vector-borne transmitted disease, thus transmission depends on the presence of competent mosquito species, which is directly related to favorable climate conditions for its development and survival. Cardiopulmonary dirofilariasis is mainly located in countries with temperate and tropical climates. Europe is one of the continents where animal dirofilariasis has been studied more extensively. In this article we review the current prevalence of canine and feline cardiopulmonary dirofilariasis in the European continent, the transmission vectors, the current changes in the distribution and the possible causes, though the analysis of the epidemiological studies carried out until 2001 and between 2002-2011. The highest prevalences have been observed in the southern European countries, which are considered historically endemic/hyperendemic countries. Studies carried out in the last 10 years suggest an expansion of cardiopulmonary dirofilariasis in dogs towards central and northern Europe. Several factors can exert an influence on the spreading of the disease, such as movement of infected animals, the introduction of new species of mosquitoes able to act as vectors, the climate change caused by the global warming, and development of human activity in new areas. Veterinary controls to prevent the spreading of this disease, programs of control of vectors, and adequate protocols of prevention of dirofilariasis in the susceptible species should be carried out.

Regulation of the Immune Response to α-Gal and Vector-borne Diseases.

Science.gov (United States)

Cabezas-Cruz, Alejandro; Mateos-Hernández, Lourdes; Pérez-Cruz, Magdiel; Valdés, James J; Mera, Isabel G Fernández de; Villar, Margarita; de la Fuente, José

2015-10-01

Vector-borne diseases (VBD) challenge our understanding of emerging diseases. Recently, arthropod vectors have been involved in emerging anaphylactic diseases. In particular, the immunoglobulin E (IgE) antibody response to the carbohydrate Galα1-3Galβ1-(3)4GlcNAc-R (α-gal) following a tick bite was associated with allergies to red meat, cetuximab, and gelatin. By contrast, an anti-α-gal IgM antibody response was shown to protect against mosquito-borne malaria. Herein, we highlight the interplay between the gut microbiota, vectors, transmitted pathogens, and the regulation of the immune response as a model to understand the protective or allergic effect of α-gal. Establishing the source of α-gal in arthropod vectors and the immune response to vector bites and transmitted pathogens will be essential for diagnosing, treating, and ultimately preventing these emerging anaphylactic and other vector-borne diseases. Copyright © 2015 Elsevier Ltd. All rights reserved.

Transgenerational interactions between pesticide exposure and warming in a vector mosquito

DEFF Research Database (Denmark)

Tran, Tam T.; Janssens, Lizanne; Dinh, Khuong Van

2018-01-01

of single and combined exposure to warming (4°C increase) and the pesticide chlorpyrifos on life history traits of the vector mosquito Culex pipiens. Parental exposure to a single stressor, either warming or the pesticide, had negative effects on the offspring: both parental exposure to warming...

[Public health pests. Arthropods and rodents as causative disease agents as well as reservoirs and vectors of pathogens].

Science.gov (United States)

Faulde, M; Freise, J

2014-05-01

Globally, infectious diseases pose the most important cause of death. Among known human pathogenic diseases, approximately 50 % are zoonoses. When considering emerging infectious diseases separately 73 % currently belong to the group of zoonoses. In Central Europe, hard ticks show by far the biggest potential as vectors of agents of human disease. Lyme borreliosis, showing an estimated annual incidence between 60,000 and 214,000 cases is by far the most frequent tick-borne disease in Germany. Continually, formerly unknown disease agents could be discovered in endemic vector species. Additionally, introduction of new arthropod vectors and/or agents of disease occur constantly. Recently, five mosquito species of the genus Aedes have been newly introduced to Europe where they are currently spreading in different regions. Uncommon autochthonous transmission of dengue and chikungunya fever viruses in Southern Europe could be directly linked to these vector species and of these Ae. albopictus and Ae. japonicus are currently reported to occur in Germany. The German Protection against Infection Act only covers the control of public health pests which are either active hematophagous vectors or mechanical transmitters of agents of diseases. Use of officially recommended biocidal products aiming to interrupt transmission cycles of vector-borne diseases, is confined to infested buildings only, including sewage systems in the case of Norway rat control. Outdoor vectors, such as hard ticks and mosquitoes, are currently not taken into consideration. Additionally, adjustments of national public health regulations, detailed arthropod vector and rodent reservoir mapping, including surveillance of vector-borne disease agents, are necessary in order to mitigate future disease risks.

Inter-epidemic abundance and distribution of potential mosquito vectors for Rift Valley fever virus in Ngorongoro district, Tanzania.

Science.gov (United States)

Mweya, Clement N; Kimera, Sharadhuli I; Mellau, Lesakit S B; Mboera, Leonard E G

2015-01-01

Rift Valley fever (RVF) is a mosquito-borne viral zoonosis that primarily affects ruminants but also has the capacity to infect humans. To determine the abundance and distribution of mosquito vectors in relation to their potential role in the virus transmission and maintenance in disease epidemic areas of Ngorongoro district in northern Tanzania. A cross-sectional entomological investigation was carried out before the suspected RVF outbreak in October 2012. Mosquitoes were sampled both outdoors and indoors using the Centre for Disease Control (CDC) light traps and Mosquito Magnets baited with attractants. Outdoor traps were placed in proximity with breeding sites and under canopy in banana plantations close to the sleeping places of animals. A total of 1,823 mosquitoes were collected, of which 87% (N=1,588) were Culex pipiens complex, 12% (N=226) Aedes aegypti, and 0.5% (N=9) Anopheles species. About two-thirds (67%; N=1,095) of C. pipiens complex and nearly 100% (N=225) of A. aegypti were trapped outdoors using Mosquito Magnets. All Anopheles species were trapped indoors using CDC light traps. There were variations in abundance of C. pipiens complex and A. aegypti among different ecological and vegetation habitats. Over three quarters (78%) of C. pipiens complex and most (85%) of the A. aegypti were trapped in banana and maize farms. Both C. pipiens complex and A. aegypti were more abundant in proximity with cattle and in semi-arid thorn bushes and lower Afro-montane. The highest number of mosquitoes was recorded in villages that were most affected during the RVF epidemic of 2007. Of the tested 150 pools of C. pipiens complex and 45 pools of A. aegypti, none was infected with RVF virus. These results provide insights into unique habitat characterisation relating to mosquito abundances and distribution in RVF epidemic-prone areas of Ngorongoro district in northern Tanzania.

Identification of Blood Meals from Potential Arbovirus Mosquito Vectors in the Peruvian Amazon Basin.

Science.gov (United States)

Palermo, Pedro M; Aguilar, Patricia V; Sanchez, Juan F; Zorrilla, Víctor; Flores-Mendoza, Carmen; Huayanay, Anibal; Guevara, Carolina; Lescano, Andrés G; Halsey, Eric S

2016-11-02

The transmission dynamics of many arboviruses in the Amazon Basin region have not been fully elucidated, including the vectors and natural reservoir hosts. Identification of blood meal sources in field-caught mosquitoes could yield information for identifying potential arbovirus vertebrate hosts. We identified blood meal sources in 131 mosquitoes collected from areas endemic for arboviruses in the Peruvian Department of Loreto by sequencing polymerase chain reaction amplicons of the cytochrome b gene. Psorophora (Janthinosoma) albigenu, Psorophora (Grabhamia) cingulata, Mansonia humeralis, Anopheles oswaldoi s.l., and Anopheles benarrochi s.l. had mainly anthropophilic feeding preferences; Aedes (Ochlerotatus) serratus, and Aedes (Ochlerotatus) fulvus had feeding preferences for peridomestic animals; and Culex (Melanoconion) spp. fed on a variety of vertebrates, mainly rodents (spiny rats), birds, and amphibians. On the basis of these feeding preferences, many mosquitoes could be considered as potential enzootic and bridge arbovirus vectors in the Amazon Basin of Peru. © The American Society of Tropical Medicine and Hygiene.

Analyzing mosquito (Diptera: culicidae diversity in Pakistan by DNA barcoding.

Directory of Open Access Journals (Sweden)

Muhammad Ashfaq

Full Text Available Although they are important disease vectors mosquito biodiversity in Pakistan is poorly known. Recent epidemics of dengue fever have revealed the need for more detailed understanding of the diversity and distributions of mosquito species in this region. DNA barcoding improves the accuracy of mosquito inventories because morphological differences between many species are subtle, leading to misidentifications.Sequence variation in the barcode region of the mitochondrial COI gene was used to identify mosquito species, reveal genetic diversity, and map the distribution of the dengue-vector species in Pakistan. Analysis of 1684 mosquitoes from 491 sites in Punjab and Khyber Pakhtunkhwa during 2010-2013 revealed 32 species with the assemblage dominated by Culex quinquefasciatus (61% of the collection. The genus Aedes (Stegomyia comprised 15% of the specimens, and was represented by six taxa with the two dengue vector species, Ae. albopictus and Ae. aegypti, dominant and broadly distributed. Anopheles made up another 6% of the catch with An. subpictus dominating. Barcode sequence divergence in conspecific specimens ranged from 0-2.4%, while congeneric species showed from 2.3-17.8% divergence. A global haplotype analysis of disease-vectors showed the presence of multiple haplotypes, although a single haplotype of each dengue-vector species was dominant in most countries. Geographic distribution of Ae. aegypti and Ae. albopictus showed the later species was dominant and found in both rural and urban environments.As the first DNA-based analysis of mosquitoes in Pakistan, this study has begun the construction of a barcode reference library for the mosquitoes of this region. Levels of genetic diversity varied among species. Because of its capacity to differentiate species, even those with subtle morphological differences, DNA barcoding aids accurate tracking of vector populations.

Attacking the mosquito on multiple fronts: Insights from the Vector Control Optimization Model (VCOM for malaria elimination.

Directory of Open Access Journals (Sweden)

Samson S Kiware

Full Text Available Despite great achievements by insecticide-treated nets (ITNs and indoor residual spraying (IRS in reducing malaria transmission, it is unlikely these tools will be sufficient to eliminate malaria transmission on their own in many settings today. Fortunately, field experiments indicate that there are many promising vector control interventions that can be used to complement ITNs and/or IRS by targeting a wide range of biological and environmental mosquito resources. The majority of these experiments were performed to test a single vector control intervention in isolation; however, there is growing evidence and consensus that effective vector control with the goal of malaria elimination will require a combination of interventions.We have developed a model of mosquito population dynamic to describe the mosquito life and feeding cycles and to optimize the impact of vector control intervention combinations at suppressing mosquito populations. The model simulations were performed for the main three malaria vectors in sub-Saharan Africa, Anopheles gambiae s.s, An. arabiensis and An. funestus. We considered areas having low, moderate and high malaria transmission, corresponding to entomological inoculation rates of 10, 50 and 100 infective bites per person per year, respectively. In all settings, we considered baseline ITN coverage of 50% or 80% in addition to a range of other vector control tools to interrupt malaria transmission. The model was used to sweep through parameters space to select the best optimal intervention packages. Sample model simulations indicate that, starting with ITNs at a coverage of 50% (An. gambiae s.s. and An. funestus or 80% (An. arabiensis and adding interventions that do not require human participation (e.g. larviciding at 80% coverage, endectocide treated cattle at 50% coverage and attractive toxic sugar baits at 50% coverage may be sufficient to suppress all the three species to an extent required to achieve local malaria

Transgenerational interactions between a pesticide and warming in a vector mosquito

DEFF Research Database (Denmark)

Tran, T.; Dinh, Khuong Van; Stoks, R.

may change in a polluted environment. We set up a full-factorial transgenerational experiment where Culex pipiens vector mosquitoes were reared at two temperatures (20°C vs 24°C) and, when they reached the final larval stage, exposed to one of two chlorpyrifos treatments (absent vs present). We...

Identification of Blood Meals from Potential Arbovirus Mosquito Vectors in the Peruvian Amazon Basin

OpenAIRE

Palermo, Pedro M.; Aguilar, Patricia V.; Sanchez, Juan F.; Zorrilla, Víctor; Flores-Mendoza, Carmen; Huayanay, Anibal; Guevara, Carolina; Lescano, Andrés G.; Halsey, Eric S.

2016-01-01

The transmission dynamics of many arboviruses in the Amazon Basin region have not been fully elucidated, including the vectors and natural reservoir hosts. Identification of blood meal sources in field-caught mosquitoes could yield information for identifying potential arbovirus vertebrate hosts. We identified blood meal sources in 131 mosquitoes collected from areas endemic for arboviruses in the Peruvian Department of Loreto by sequencing polymerase chain reaction amplicons of the cytochrom...

Non-Genetic Determinants of Mosquito Competence for Malaria Parasites

Science.gov (United States)

Lefèvre, Thierry; Vantaux, Amélie; Dabiré, Kounbobr R.; Mouline, Karine; Cohuet, Anna

2013-01-01

Understanding how mosquito vectors and malaria parasites interact is of fundamental interest, and it also offers novel perspectives for disease control. Both the genetic and environmental contexts are known to affect the ability of mosquitoes to support malaria development and transmission, i.e., vector competence. Although the role of environment has long been recognized, much work has focused on host and parasite genetic effects. However, the last few years have seen a surge of studies revealing a great diversity of ways in which non-genetic factors can interfere with mosquito-Plasmodium interactions. Here, we review the current evidence for such environmentally mediated effects, including ambient temperature, mosquito diet, microbial gut flora, and infection history, and we identify additional factors previously overlooked in mosquito-Plasmodium interactions. We also discuss epidemiological implications, and the evolutionary consequences for vector immunity and parasite transmission strategies. Finally, we propose directions for further research and argue that an improved knowledge of non-genetic influences on mosquito-Plasmodium interactions could aid in implementing conventional malaria control measures and contribute to the design of novel strategies. PMID:23818841

Non-genetic determinants of mosquito competence for malaria parasites.

Directory of Open Access Journals (Sweden)

Thierry Lefèvre

Full Text Available Understanding how mosquito vectors and malaria parasites interact is of fundamental interest, and it also offers novel perspectives for disease control. Both the genetic and environmental contexts are known to affect the ability of mosquitoes to support malaria development and transmission, i.e., vector competence. Although the role of environment has long been recognized, much work has focused on host and parasite genetic effects. However, the last few years have seen a surge of studies revealing a great diversity of ways in which non-genetic factors can interfere with mosquito-Plasmodium interactions. Here, we review the current evidence for such environmentally mediated effects, including ambient temperature, mosquito diet, microbial gut flora, and infection history, and we identify additional factors previously overlooked in mosquito-Plasmodium interactions. We also discuss epidemiological implications, and the evolutionary consequences for vector immunity and parasite transmission strategies. Finally, we propose directions for further research and argue that an improved knowledge of non-genetic influences on mosquito-Plasmodium interactions could aid in implementing conventional malaria control measures and contribute to the design of novel strategies.

Population genetics of two key mosquito vectors of Rift Valley Fever virus reveals new insights into the changing disease outbreak patterns in Kenya.

Directory of Open Access Journals (Sweden)

David P Tchouassi

2014-12-01

Full Text Available Rift Valley fever (RVF outbreaks in Kenya have increased in frequency and range to include northeastern Kenya where viruses are increasingly being isolated from known (Aedes mcintoshi and newly-associated (Ae. ochraceus vectors. The factors contributing to these changing outbreak patterns are unclear and the population genetic structure of key vectors and/or specific virus-vector associations, in particular, are under-studied. By conducting mitochondrial and nuclear DNA analyses on >220 Kenyan specimens of Ae. mcintoshi and Ae. ochraceus, we uncovered high levels of vector complexity which may partly explain the disease outbreak pattern. Results indicate that Ae. mcintoshi consists of a species complex with one of the member species being unique to the newly-established RVF outbreak-prone northeastern region of Kenya, whereas Ae. ochraceus is a homogeneous population that appears to be undergoing expansion. Characterization of specimens from a RVF-prone site in Senegal, where Ae. ochraceus is a primary vector, revealed direct genetic links between the two Ae. ochraceus populations from both countries. Our data strongly suggest that unlike Ae. mcintoshi, Ae. ochraceus appears to be a relatively recent, single 'introduction' into Kenya. These results, together with increasing isolations from this vector, indicate that Ae. ochraceus will likely be of greater epidemiological importance in future RVF outbreaks in Kenya. Furthermore, the overall vector complexity calls into question the feasibility of mosquito population control approaches reliant on genetic modification.

Population Genetics of Two Key Mosquito Vectors of Rift Valley Fever Virus Reveals New Insights into the Changing Disease Outbreak Patterns in Kenya

Science.gov (United States)

Tchouassi, David P.; Bastos, Armanda D. S.; Sole, Catherine L.; Diallo, Mawlouth; Lutomiah, Joel; Mutisya, James; Mulwa, Francis; Borgemeister, Christian; Sang, Rosemary; Torto, Baldwyn

2014-01-01

Rift Valley fever (RVF) outbreaks in Kenya have increased in frequency and range to include northeastern Kenya where viruses are increasingly being isolated from known (Aedes mcintoshi) and newly-associated (Ae. ochraceus) vectors. The factors contributing to these changing outbreak patterns are unclear and the population genetic structure of key vectors and/or specific virus-vector associations, in particular, are under-studied. By conducting mitochondrial and nuclear DNA analyses on >220 Kenyan specimens of Ae. mcintoshi and Ae. ochraceus, we uncovered high levels of vector complexity which may partly explain the disease outbreak pattern. Results indicate that Ae. mcintoshi consists of a species complex with one of the member species being unique to the newly-established RVF outbreak-prone northeastern region of Kenya, whereas Ae. ochraceus is a homogeneous population that appears to be undergoing expansion. Characterization of specimens from a RVF-prone site in Senegal, where Ae. ochraceus is a primary vector, revealed direct genetic links between the two Ae. ochraceus populations from both countries. Our data strongly suggest that unlike Ae. mcintoshi, Ae. ochraceus appears to be a relatively recent, single 'introduction' into Kenya. These results, together with increasing isolations from this vector, indicate that Ae. ochraceus will likely be of greater epidemiological importance in future RVF outbreaks in Kenya. Furthermore, the overall vector complexity calls into question the feasibility of mosquito population control approaches reliant on genetic modification. PMID:25474018

Large-Scale Removal of Invasive Honeysuckle Decreases Mosquito and Avian Host Abundance.

Science.gov (United States)

Gardner, Allison M; Muturi, Ephantus J; Overmier, Leah D; Allan, Brian F

2017-12-01

Invasive species rank second only to habitat destruction as a threat to native biodiversity. One consequence of biological invasions is altered risk of exposure to infectious diseases in human and animal populations. The distribution and prevalence of mosquito-borne diseases depend on the complex interactions between the vector, the pathogen, and the human or wildlife reservoir host. These interactions are highly susceptible to disturbance by invasive species, including terrestrial plants. We conducted a 2-year field experiment using a Before-After/Control-Impact design to examine how removal of invasive Amur honeysuckle (Lonicera maackii) in a forest fragment embedded within a residential neighborhood affects the abundance of mosquitoes, including two of the most important vectors of West Nile virus, Culex pipiens and Cx. restuans. We also assessed any potential changes in avian communities and local microclimate associated with Amur honeysuckle removal. We found that (1) removal of Amur honeysuckle reduces the abundance of both vector and non-vector mosquito species that commonly feed on human hosts, (2) the abundance and composition of avian hosts is altered by honeysuckle removal, and (3) areas invaded with honeysuckle support local microclimates that are favorable to mosquito survival. Collectively, our investigations demonstrate the role of a highly invasive understory shrub in determining the abundance and distribution of mosquitoes and suggest potential mechanisms underlying this pattern. Our results also give rise to additional questions regarding the general impact of invasive plants on vector-borne diseases and the spatial scale at which removal of invasive plants may be utilized to effect disease control.

Mosquito distribution in a saltmarsh: determinants of eggs in a variable environment.

Science.gov (United States)

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.

siRNA-Mediated Silencing of doublesex during Female Development of the Dengue Vector Mosquito Aedes aegypti.

Directory of Open Access Journals (Sweden)

Keshava Mysore

2015-11-01

Full Text Available The development of sex-specific traits, including the female-specific ability to bite humans and vector disease, is critical for vector mosquito reproduction and pathogen transmission. Doublesex (Dsx, a terminal transcription factor in the sex determination pathway, is known to regulate sex-specific gene expression during development of the dengue fever vector mosquito Aedes aegypti. Here, the effects of developmental siRNA-mediated dsx silencing were assessed in adult females. Targeting of dsx during A. aegypti development resulted in decreased female wing size, a correlate for body size, which is typically larger in females. siRNA-mediated targeting of dsx also resulted in decreased length of the adult female proboscis. Although dsx silencing did not impact female membrane blood feeding or mating behavior in the laboratory, decreased fecundity and fertility correlated with decreased ovary length, ovariole length, and ovariole number in dsx knockdown females. Dsx silencing also resulted in disruption of olfactory system development, as evidenced by reduced length of the female antenna and maxillary palp and the sensilla present on these structures, as well as disrupted odorant receptor expression. Female lifespan, a critical component of the ability of A. aegypti to transmit pathogens, was also significantly reduced in adult females following developmental targeting of dsx. The results of this investigation demonstrate that silencing of dsx during A. aegypti development disrupts multiple sex-specific morphological, physiological, and behavioral traits of adult females, a number of which are directly or indirectly linked to mosquito reproduction and pathogen transmission. Moreover, the olfactory phenotypes observed connect Dsx to development of the olfactory system, suggesting that A. aegypti will be an excellent system in which to further assess the developmental genetics of sex-specific chemosensation.

Risk factors for the presence of dengue vector mosquitoes, and determinants of their prevalence and larval site selection in Dhaka, Bangladesh.

Science.gov (United States)

Paul, Kishor Kumar; Dhar-Chowdhury, Parnali; Haque, C Emdad; Al-Amin, Hasan Mohammad; Goswami, Doli Rani; Kafi, Mohammad Abdullah Heel; Drebot, Michael A; Lindsay, L Robbin; Ahsan, Gias Uddin; Brooks, W Abdullah

2018-01-01

Dengue viruses are responsible for over 100 million infections a year worldwide and are a public health concern in Bangladesh. Although risk of transmission is high, data on vector population characteristics are scanty in Bangladesh; therefore, a comprehensive prediction of the patterns of local virus transmission is not possible. Recognizing these gaps, multi-year entomological surveys were carried out in Dhaka, where the disease is most frequently reported. The specific objectives of the present study are threefold: i) to determine the risk factors for the presence of Aedes mosquitoes; ii) to identify the types of most productive and key containers; and iii) to estimate the effects of climatic factors on Aedes abundance in the city of Dhaka, Bangladesh. Entomological surveys were conducted in 12 out of 90 wards in Dhaka. These wards were selected using a probability proportional sampling procedure during the monsoon seasons in 2011, 2012 and 2013 and in the dry season in 2012. All containers inside and around sampled households were inspected for mosquito larvae and pupae, and containers were classified according to their relative size, use pattern, and materials of construction. During the study period (2011-2013), 12,680 larvae and pupae were collected. About 82% of the identified immature mosquitoes were Aedes aegypti, while the remainder were Ae. albopictus and other mosquito species. The largest number of immature mosquitoes was collected from tires and refrigerator trays during 2011 and 2012 monsoon seasons. Conversely, plastic drums were the most productive during the 2012 dry and 2013 monsoon season. Vehicle parts and discarded construction materials were the most efficient producers of Aedes mosquitoes in all surveys. The presence of Aedes mosquitoes was significantly (p Container location, presence of vegetation, and availability of shade for containers were also significantly associated with finding immature Aedes mosquitoes, based on multivariable

[Epidemiology of arbovirus diseases: use and value of physiologic age determination of female mosquito vectors].

Science.gov (United States)

Mondet, B

1996-01-01

The physiological age of Yellow Fever Aedes females in Africa was studied during four years, from 1988 to 1992. We used a method, according to Polovodova's method, which looks for the "yellow body" under natural light. Those yellow bodies exist in the old females, the "parous" ones, and not in the young females, the "nulliparous" ones. We present some results to illustrate the interest of studying the physiological age of mosquitoes in the epidemiology of the arboviral diseases. The transmission risk, in relation with abundance and parity rate was illustrated, in particular for Aedes africanus and Aedes luteocephalus, which is useful to compare species, or with a given species, to compare periods. The parity rate of Aedes furcifer females was studied on 6 points along a transect between a forest and a village. The rate and the abundance of the females caught on human bates are inversely proportional. The parity rate is minimum in the canopy forest (about 50%) and maximum inside a house (100%). The rains have different consequences on the species, according to the period of fall. At the beginning of the dry season, they bring about hatching, but not at the end of the dry season. Massive hatching, will occur just at the beginning of the rainy season, some weeks later. Studying the physiological age of Ae. africanus females, the number of nulliparous is not related to the rain. That means a possibility of "natural" hatching for part of the eggs. Among the female of the dry season, young females are found, which is important for the transmission capacity. The method, described herein, to determine the physiological age is perfectly applicable to the Yellow Fever vector Haemagogus janthinomys in Southern America. But for the Dengue vectors Aedes aegypti and probably Aedes albopictus, the Detinova's method seems better. Actually, it seems important to study the physiological age of the vectors Ae. aegypti and Ae. albopictus, as well as the evolution of the physiological

Biology and Role of Aedes albopictus (Skuse 1894 as Vector of Diseases

Directory of Open Access Journals (Sweden)

Hasan Boesri

2011-12-01

Full Text Available Behavior of the mosquito Aedes albopictus is generally res ting outside the home with the brood in a natural or artificial containers protected from sunlight. Human biting activity between the hours of9:00 to 11:00 and between the hours of 17:00 to 18:00 inside and outside the home. The period of rest after sucking the blood 4-5 days and is ready to lie. Habitat or the environment that most coveted of th is mosquito is a forest or gar­den with temperatures of 24-30 0 C. eggs hatch after 4-5 days with a temperature of 24-30 0 C, the eggs usually form elus ters of 49-60 eggs Larvae and pupae usually found in contain­ers, pieces of bambo containing water. The period of the larvae to adults between 20-25 days. The spread of Ae albopictus mosquitoes from Africa, India, Pakistan, Sri Lanka, Thai­land, Malaysia, Vietnam, Papua New Guinea, northern Australia, and Indonesia. Role in disease transmission is a secondary vector or as the primary vector of dengue hemorrhagic fever. On viral diseases that attack the nerves like encephalistis Japanese, Western or East­ern encephalistis, and Chikuguya has been demonstrated by laboratories, as well as on ani­mal diseases caused by Dirofilaria immitis agent, Plasmodium lophurae, P. gallinaceum, and P. fallax.

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

OpenAIRE

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

2017-01-01

Background 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...

Larvicidal potentiality, longevity and fecundity inhibitory activities of Bacillus sphaericus (Bs G3-IV on vector mosquitoes, Aedes aegypti and Culex quinquefasciatus

Directory of Open Access Journals (Sweden)

Arjunan Nareshkumar

2012-12-01

Full Text Available Intervention measures to control the transmission of vector-borne diseases include control of the vector population. In mosquito control, synthetic insecticides used against both the larvae (larvicides and adults (adulticides create numerous problems, such as environmental pollution, insecticide resistance and toxic hazards to humans. In the present study, a bacterial pesticide, Bacillus sphaericus (Bs G3-IV, was used to control the dengue and filarial vectors, Aedes aegypti and Culex quinquefasciatus. Bacillus sphaericus (Bs G3-IV was very effective against Aedes aegypti and Culex quinquefasciatus, showing significant larval mortality. Evaluated lethal concentrations (LC50 and LC90 were age-dependent, with early instars requiring a lower concentration compared with later stages of mosquitoes. Culex quinquefasciatus was more susceptible to Bacillus sphaericus (Bs G3-IV than was Aedes aegypti. Fecundity rate was highly reduced after treatment with different concentrations of Bacillus sphaericus (Bs G3-IV. Larval and pupal longevity both decreased after treatment with Bacillus sphaericus (Bs G3-IV, total number of days was lower in the B. sphaericus treatments compared with the control. Our results show the bacterial pesticide Bacillus sphaericus (Bs G3-IV to be an effective mosquito control agent that can be used for more integrated pest management programs.

Risk of exposure to potential vector mosquitoes for rural workers in Northern Lao PDR.

Directory of Open Access Journals (Sweden)

Julie-Anne A Tangena

2017-07-01

Full Text Available One major consequence of economic development in South-East Asia has been a rapid expansion of rubber plantations, in which outbreaks of dengue and malaria have occurred. Here we explored the difference in risk of exposure to potential dengue, Japanese encephalitis (JE, and malaria vectors between rubber workers and those engaged in traditional forest activities in northern Laos PDR.Adult mosquitoes were collected for nine months in secondary forests, mature and immature rubber plantations, and villages. Human behavior data were collected using rapid participatory rural appraisals and surveys. Exposure risk was assessed by combining vector and human behavior and calculating the basic reproduction number (R0 in different typologies. Compared to those that stayed in the village, the risk of dengue vector exposure was higher for those that visited the secondary forests during the day (odds ratio (OR 36.0, for those living and working in rubber plantations (OR 16.2 and for those that tapped rubber (OR 3.2. Exposure to JE vectors was also higher in the forest (OR 1.4 and, similar when working (OR 1.0 and living in the plantations (OR 0.8. Exposure to malaria vectors was greater in the forest (OR 1.3, similar when working in the plantations (OR 0.9 and lower when living in the plantations (OR 0.6. R0 for dengue was >2.8 for all habitats surveyed, except villages where R0≤0.06. The main malaria vector in all habitats was Anopheles maculatus s.l. in the rainy season and An. minimus s.l. in the dry season.The highest risk of exposure to vector mosquitoes occurred when people visit natural forests. However, since rubber workers spend long periods in the rubber plantations, their risk of exposure is increased greatly compared to those who temporarily enter natural forests or remain in the village. This study highlights the necessity of broadening mosquito control to include rubber plantations.

Transfer of toxin genes to alternate bacterial hosts for mosquito control

Directory of Open Access Journals (Sweden)

Sergio Orduz

1995-02-01

Full Text Available Mosquitoes are vector of serious human and animal diseases, such as malaria, dengue, yellow fever, among others. The use of biological control agents has provide an environmentally safe and highly specific alternative to the use of chemical insecticides in the control of vector borne diseases. Bacillus thuringiensis and B. sphaericus produce toxic proteins to mosquito larvae. Great progress has been made on the biochemical and molecular characterization of such proteins and the genes encoding them. Nevertheless, the low residuality of these biological insecticides is one of the major drawbacks. This article present some interesting aspects of the mosquito larvae feeding habits and review the attempts that have been made to genetically engineer microorganisms that while are used by mosquito larvae as a food source should express the Bacillus toxin genes in order to improve the residuality and stability in the mosquito breeding ponds.

Mosquito-host interactions during and after an outbreak of equine viral encephalitis in Eastern Panama.

Directory of Open Access Journals (Sweden)

Wayra G Navia-Gine

Full Text Available Mosquito blood meals provide information about the feeding habits and host preference of potential arthropod-borne disease vectors. Although mosquito-borne diseases are ubiquitous in the Neotropics, few studies in this region have assessed patterns of mosquito-host interactions, especially during actual disease outbreaks. Based on collections made during and after an outbreak of equine viral encephalitis, we identified the source of 338 blood meals from 10 species of mosquitoes from Aruza Abajo, a location in Darien province in eastern Panama. A PCR based method targeting three distinct mitochondrial targets and subsequent DNA sequencing was used in an effort to delineate vector-host relationships. At Aruza Abajo, large domesticated mammals dominated the assemblage of mosquito blood meals while wild bird and mammal species represented only a small portion of the blood meal pool. Most mosquito species fed on a variety of hosts; foraging index analysis indicates that eight of nine mosquito species utilize hosts at similar proportions while a stochastic model suggests dietary overlap among species was greater than would be expected by chance. The results from our null-model analysis of mosquito diet overlap are consistent with the hypothesis that in landscapes where large domestic animals dominate the local biomass, many mosquito species show little host specificity, and feed upon hosts in proportion to their biomass, which may have implications for the role of livestocking patterns in vector-borne disease ecology.

[Important vector-borne infectious diseases among humans in Germany. Epidemiological aspects].

Science.gov (United States)

Frank, C; Faber, M; Hellenbrand, W; Wilking, H; Stark, K

2014-05-01

Vector-borne infections pathogenic to humans play an important role in Germany. The relevant zoonotic pathogens are either endemic throughout Germany (e.g. Borrelia burgdorferi sensu latu) or only in specific regions, e.g. tick-borne encephalitis (TBE) virus and hantavirus. They cause a substantial burden of disease. Prevention and control largely rely on public advice and the application of personal protective measures (e.g. TBE virus vaccination and protection against vectors). High quality surveillance and targeted epidemiological studies are fundamental for the evaluation of temporal and spatial risks of infection and the effectiveness of preventive measures. Aside from endemic pathogens, vector-borne infections acquired abroad, mostly transmitted by mosquitoes, have to be systematically and intensively monitored as well, to assess the risk of infection for German residents traveling abroad and to adequately evaluate the risk of autochthonous transmission. Related issues, such as invasive species of mosquitoes in Germany and climate change, have to be taken into consideration. Such pathogens include West Nile, dengue and chikungunya viruses, as well as malaria parasites (Plasmodium species). The article presents an overview of the epidemiological situation of selected relevant vector-borne infections in Germany.

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

Science.gov (United States)

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.

Major emerging vector-borne zoonotic diseases of public health importance in Canada.

Science.gov (United States)

Kulkarni, Manisha A; Berrang-Ford, Lea; Buck, Peter A; Drebot, Michael A; Lindsay, L Robbin; Ogden, Nicholas H

2015-06-10

In Canada, the emergence of vector-borne diseases may occur via international movement and subsequent establishment of vectors and pathogens, or via northward spread from endemic areas in the USA. Re-emergence of endemic vector-borne diseases may occur due to climate-driven changes to their geographic range and ecology. Lyme disease, West Nile virus (WNV), and other vector-borne diseases were identified as priority emerging non-enteric zoonoses in Canada in a prioritization exercise conducted by public health stakeholders in 2013. We review and present the state of knowledge on the public health importance of these high priority emerging vector-borne diseases in Canada. Lyme disease is emerging in Canada due to range expansion of the tick vector, which also signals concern for the emergence of human granulocytic anaplasmosis, babesiosis, and Powassan virus. WNV has been established in Canada since 2001, with epidemics of varying intensity in following years linked to climatic drivers. Eastern equine encephalitis virus, Jamestown Canyon virus, snowshoe hare virus, and Cache Valley virus are other mosquito-borne viruses endemic to Canada with the potential for human health impact. Increased surveillance for emerging pathogens and vectors and coordinated efforts among sectors and jurisdictions will aid in early detection and timely public health response.

[Climate change - a pioneer for the expansion of canine vector-borne diseases?].

Science.gov (United States)

Krämer, F; Mencke, N

2011-01-01

Vector-transmitted diseases are one of the major contributors to the global burden of disease in humans and animals. Climate change is consistently held responsible for the spread of parasitic acarid and insect vectors such as ticks, fleas, sand flies and mosquitoes, and their transmitted pathogens (in the case of the dog the so-called canine vector-borne diseases [CVBD]). Currently, there is only insufficient data available to prove whether climate change is a major driving force for vector and disease expansion, but the evidence is growing. Other reasons, such as ecological, demographic and socio-economic factors, e.g. pet travel into and pet import from endemic areas, also play a role in this development. Apart from all the controversial discussion of the factors leading to vector and disease expansion, preventative measures should include dog owners' education as they are responsible for individual parasite protection as well as for the minimisation of adverse risk behaviour, e.g. regarding pet travel. Broad-spectrum vector control should be practised by using parasiticides that repel and kill blood feeders in order to minimize the risk of CVBD-pathogen transmission.

Role of Culex and Anopheles mosquito species as potential vectors of rift valley fever virus in Sudan outbreak, 2007

Directory of Open Access Journals (Sweden)

Galal Fatma H

2010-03-01

Full Text Available Abstract Background Rift Valley fever (RVF is an acute febrile arthropod-borne viral disease of man and animals caused by a member of the Phlebovirus genus, one of the five genera in the family Bunyaviridae. RVF virus (RVFV is transmitted between animals and human by mosquitoes, particularly those belonging to the Culex, Anopheles and Aedes genera. Methods Experiments were designed during RVF outbreak, 2007 in Sudan to provide an answer about many raised questions about the estimated role of vector in RVFV epidemiology. During this study, adult and immature mosquito species were collected from Khartoum and White Nile states, identified and species abundance was calculated. All samples were frozen individually for further virus detection. Total RNA was extracted from individual insects and RVF virus was detected from Culex, Anopheles and Aedes species using RT-PCR. In addition, data were collected about human cases up to November 24th, 2007 to asses the situation of the disease in affected states. Furthermore, a historical background of the RVF outbreaks was discussed in relation to global climatic anomalies and incriminated vector species. Results A total of 978 mosquitoes, belonging to 3 genera and 7 species, were collected during Sudan outbreak, 2007. Anopheles gambiae arabiensis was the most frequent species (80.7% in White Nile state. Meanwhile, Cx. pipiens complex was the most abundant species (91.2% in Khartoum state. RT-PCR was used and successfully amplified 551 bp within the M segment of the tripartite negative-sense single stranded RNA genome of RVFV. The virus was detected in female, male and larval stages of Culex and Anopheles species. The most affected human age interval was 15-29 years old followed by ≥ 45 years old, 30-44 years old, and then 5-14 years old. Regarding to the profession, housewives followed by farmers, students, shepherd, workers and the free were more vulnerable to the infection. Furthermore, connection between

Inter-epidemic abundance and distribution of potential mosquito vectors for Rift Valley fever virus in Ngorongoro district, Tanzania

Directory of Open Access Journals (Sweden)

Clement N. Mweya

2015-01-01

Full Text Available Background: Rift Valley fever (RVF is a mosquito-borne viral zoonosis that primarily affects ruminants but also has the capacity to infect humans. Objective: To determine the abundance and distribution of mosquito vectors in relation to their potential role in the virus transmission and maintenance in disease epidemic areas of Ngorongoro district in northern Tanzania. Methods: A cross-sectional entomological investigation was carried out before the suspected RVF outbreak in October 2012. Mosquitoes were sampled both outdoors and indoors using the Centre for Disease Control (CDC light traps and Mosquito Magnets baited with attractants. Outdoor traps were placed in proximity with breeding sites and under canopy in banana plantations close to the sleeping places of animals. Results: A total of 1,823 mosquitoes were collected, of which 87% (N=1,588 were Culex pipiens complex, 12% (N=226 Aedes aegypti, and 0.5% (N=9 Anopheles species. About two-thirds (67%; N=1,095 of C. pipiens complex and nearly 100% (N=225 of A. aegypti were trapped outdoors using Mosquito Magnets. All Anopheles species were trapped indoors using CDC light traps. There were variations in abundance of C. pipiens complex and A. aegypti among different ecological and vegetation habitats. Over three quarters (78% of C. pipiens complex and most (85% of the A. aegypti were trapped in banana and maize farms. Both C. pipiens complex and A. aegypti were more abundant in proximity with cattle and in semi-arid thorn bushes and lower Afro-montane. The highest number of mosquitoes was recorded in villages that were most affected during the RVF epidemic of 2007. Of the tested 150 pools of C. pipiens complex and 45 pools of A. aegypti, none was infected with RVF virus. Conclusions: These results provide insights into unique habitat characterisation relating to mosquito abundances and distribution in RVF epidemic-prone areas of Ngorongoro district in northern Tanzania.

St. Louis Encephalitis virus mosquito vectors dynamics in three different environments in relation to remotely sensed environmental conditions.

Science.gov (United States)

Batallán, Gonzalo P; Estallo, Elizabet L; Flores, Fernando S; Sartor, Paolo; Contigiani, Marta S; Almirón, Walter R

2015-06-01

In Argentina the St. Louis Encephalitis virus (SLEV) is an endemic and widely distributed pathogen transmitted by the cosmopolitan mosquito Culex quinquefasciatus. During two outbreaks in Córdoba city, in 2005 and 2010, Culex interfor was also found infected, but its role as vector of SLEV is poorly known. This mosquito species is distributed from central Argentina to southern Brazil. The primary aim of this study was to analyze the population dynamic of Cx. interfor and Cx. quinquefasciatus in three different environments (urban, suburban and non-urban) in relation to remotely sensed environmental data for vegetation (NDVI and NDWI) and temperature (brightness temperature). Cx. quinquefasciatus and Cx. interfor were found at the three sampled sites, being both the most abundant Culex species, with peaks in early and midsummer. Temporal distribution patterns of both mosquito species were highly correlated in a non-urban area of high SLEV risk transmission. Cx. quinquefasciatus and Cx. interfor were associated with the most urbanized site and the non-urban environment, respectively; high significant correlations were detected between vegetation indices and abundance of both mosquito species confirming these associations. These data provide a foundation for building density maps of these two SLEV mosquito vectors using remotely sensed data to help inform vector control programs. Copyright © 2015 Elsevier B.V. All rights reserved.

Non-Genetic Determinants of Mosquito Competence for Malaria Parasites

OpenAIRE

Lef?vre, Thierry; Vantaux, Am?lie; Dabir?, Kounbobr R.; Mouline, Karine; Cohuet, Anna

2013-01-01

Understanding how mosquito vectors and malaria parasites interact is of fundamental interest, and it also offers novel perspectives for disease control. Both the genetic and environmental contexts are known to affect the ability of mosquitoes to support malaria development and transmission, i.e., vector competence. Although the role of environment has long been recognized, much work has focused on host and parasite genetic effects. However, the last few years have seen a surge of studies reve...

Present and Future Projections of Habitat Suitability of the Asian Tiger Mosquito, a Vector of Viral Pathogens, from Global Climate Simulations.

Science.gov (United States)

Proestos, Y.; Christophides, G.; Erguler, K.; Tanarhte, M.; Waldock, J.; Lelieveld, J.

2014-12-01

Climate change can influence the transmission of vector borne diseases (VBDs) through altering the habitat suitability of insect vectors. Here we present global climate model simulations and evaluate the associated uncertainties in view of the main meteorological factors that may affect the distribution of the Asian Tiger mosquito (Aedes albopictus), which can transmit pathogens that cause Chikungunya, Dengue fever, yellow fever and various encephalitides. Using a general circulation model (GCM) at 50 km horizontal resolution to simulate mosquito survival variables including temperature, precipitation and relative humidity, we present both global and regional projections of the habitat suitability up to the middle of the 21st century. The model resolution of 50 km allows evaluation against previous projections for Europe and provides a basis for comparative analyses with other regions. Model uncertainties and performance are addressed in light of the recent CMIP5 ensemble climate model simulations for the RCP8.5 concentration pathway and using meteorological re-analysis data (ERA-Interim/ECMWF) for the recent past. Uncertainty ranges associated with the thresholds of meteorological variables that may affect the distribution of Ae. albopictus are diagnosed using fuzzy-logic methodology, notably to assess the influence of selected meteorological criteria and combinations of criteria that influence mosquito habitat suitability. From the climate projections for 2050, and adopting a habitat suitability index larger than 70%, we estimate that about 2.4 billion individuals in a land area of nearly 20 million square kilometres will potentially be exposed to Ae. albopictus. The synthesis of fuzzy-logic based on mosquito biology and climate change analysis provides new insights into the regional and global spreading of VBDs to support disease control and policy making.

Eco-friendly larvicides from Indian plants: Effectiveness of lavandulyl acetate and bicyclogermacrene on malaria, dengue and Japanese encephalitis mosquito vectors.

Science.gov (United States)

Govindarajan, Marimuthu; Benelli, Giovanni

2016-11-01

Mosquitoes (Diptera: Culicidae) are a key threat for millions of people and animals worldwide, since they act as vectors for devastating pathogens and parasites, including malaria, dengue, Japanese encephalitis, filiariasis and Zika virus. Mosquito young instars are usually targeted using organophosphates, insect growth regulators and microbial agents. Indoor residual spraying and insecticide-treated bed nets are also employed. However, these chemicals have negative effects on human health and the environment and induce resistance in a number of vectors. In this scenario, newer and safer tools have been recently implemented to enhance mosquito control. The concrete potential of screening plant species as sources of metabolites for entomological and parasitological purposes is worthy of attention, as recently elucidated by the Y. Tu's example. Here we investigated the toxicity of Heracleum sprengelianum (Apiaceae) leaf essential oil and its major compounds toward third instar larvae of the malaria vector Anopheles subpictus, the arbovirus vector Aedes albopictus and the Japanese encephalitis vector Culex tritaeniorhynchus. GC-MS analysis showed that EO major components were lavandulyl acetate (17.8%) and bicyclogermacrene (12.9%). The EO was toxic to A. subpictus, A. albopictus, and C. tritaeniorhynchus, with LC50 of 33.4, 37.5 and 40.9µg/ml, respectively. Lavandulyl acetate was more toxic to mosquito larvae if compared to bicyclogermacrene. Their LC50 were 4.17 and 10.3µg/ml for A. subpictus, 4.60 and 11.1µg/ml for A. albopictus, 5.11 and 12.5µg/ml for C. tritaeniorhynchus. Notably, the EO and its major compounds were safer to three non-target mosquito predators, Anisops bouvieri, Diplonychus indicus and Gambusia affinis, with LC50 ranging from 206 to 4219µg/ml. Overall, this study highlights that H. sprengelianum EO is a promising source of eco-friendly larvicides against three important mosquito vectors with moderate toxicity against non-target aquatic

Surveillance of arthropod vector-borne infectious diseases using remote sensing techniques: a review.

Directory of Open Access Journals (Sweden)

Satya Kalluri

2007-10-01

Full Text Available Epidemiologists are adopting new remote sensing techniques to study a variety of vector-borne diseases. Associations between satellite-derived environmental variables such as temperature, humidity, and land cover type and vector density are used to identify and characterize vector habitats. The convergence of factors such as the availability of multi-temporal satellite data and georeferenced epidemiological data, collaboration between remote sensing scientists and biologists, and the availability of sophisticated, statistical geographic information system and image processing algorithms in a desktop environment creates a fertile research environment. The use of remote sensing techniques to map vector-borne diseases has evolved significantly over the past 25 years. In this paper, we review the status of remote sensing studies of arthropod vector-borne diseases due to mosquitoes, ticks, blackflies, tsetse flies, and sandflies, which are responsible for the majority of vector-borne diseases in the world. Examples of simple image classification techniques that associate land use and land cover types with vector habitats, as well as complex statistical models that link satellite-derived multi-temporal meteorological observations with vector biology and abundance, are discussed here. Future improvements in remote sensing applications in epidemiology are also discussed.

Major vectors and vector-borne diseases in small ruminants in Ethiopia: A systematic review.

Science.gov (United States)

Asmare, Kassahun; Abayneh, Takele; Sibhat, Berhanu; Shiferaw, Dessie; Szonyi, Barbara; Krontveit, Randi I; Skjerve, Eystein; Wieland, Barbara

2017-06-01

five genera, four species of Glossina and 4 genera of biting flies were reported. Despite the evidence on presence of various vectors including ticks, flies, mosquitoes and midges, studies on vector-borne diseases in Ethiopia are surprisingly rare, especially considering risks related to climate change, which is likely to affect distribution of vectors. Thus better evidence on the current situation is urgently needed in order to prevent spread and to model future distribution scenarios. Copyright © 2017 Elsevier B.V. All rights reserved.

Monitoring the age of mosquito populations using near-infrared spectroscopy

Science.gov (United States)

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...

Chikungunya Virus–Vector Interactions

Directory of Open Access Journals (Sweden)

Lark L. Coffey

2014-11-01

Full Text Available Chikungunya virus (CHIKV is a mosquito-borne alphavirus that causes chikungunya fever, a severe, debilitating disease that often produces chronic arthralgia. Since 2004, CHIKV has emerged in Africa, Indian Ocean islands, Asia, Europe, and the Americas, causing millions of human infections. Central to understanding CHIKV emergence is knowledge of the natural ecology of transmission and vector infection dynamics. This review presents current understanding of CHIKV infection dynamics in mosquito vectors and its relationship to human disease emergence. The following topics are reviewed: CHIKV infection and vector life history traits including transmission cycles, genetic origins, distribution, emergence and spread, dispersal, vector competence, vector immunity and microbial interactions, and co-infection by CHIKV and other arboviruses. The genetics of vector susceptibility and host range changes, population heterogeneity and selection for the fittest viral genomes, dual host cycling and its impact on CHIKV adaptation, viral bottlenecks and intrahost diversity, and adaptive constraints on CHIKV evolution are also discussed. The potential for CHIKV re-emergence and expansion into new areas and prospects for prevention via vector control are also briefly reviewed.

Novel Wolbachia-transinfected Aedes aegypti mosquitoes possess diverse fitness and vector competence phenotypes.

Directory of Open Access Journals (Sweden)

Johanna E Fraser

2017-12-01

Full Text Available Wolbachia pipientis from Drosophila melanogaster (wMel is an endosymbiotic bacterium that restricts transmission of human pathogenic flaviviruses and alphaviruses, including dengue, Zika, and chikungunya viruses, when introduced into the mosquito vector Aedes aegypti. To date, wMel-infected Ae. aegypti have been released in field trials in 5 countries to evaluate the effectiveness of this strategy for disease control. Despite the success in establishing wMel-infected mosquitoes in wild populations, and the well-characterized antiviral capabilities of wMel, transinfecting different or additional Wolbachia strains into Ae. aegypti may improve disease impact, and perhaps more importantly, could provide a strategy to account for the possible evolution of resistant arboviruses. Here, we report the successful transinfection of Ae. aegypti with the Wolbachia strains wMelCS (D. melanogaster, wRi (D. simulans and wPip (Culex quinquefasciatus and assess the effects on Ae. aegypti fitness, cytoplasmic incompatibility, tissue tropism and pathogen blocking in a laboratory setting. The results demonstrate that wMelCS provides a similar degree of protection against dengue virus as wMel following an infectious blood meal, and significantly reduces viral RNA levels beyond that of wMel following a direct challenge with infectious virus in mosquitoes, with no additional fitness cost to the host. The protection provided by wRi is markedly weaker than that of wMelCS, consistent with previous characterisations of these lines in Drosophila, while wPip was found to substantially reduce the fitness of Ae. aegypti. Thus, we determine wMelCS as a key candidate for further testing in field-relevant fitness tests and viremic blood feeding challenges in a clinical setting to determine if it may represent an alternative Wolbachia strain with more desirable attributes than wMel for future field testing.

Novel Wolbachia-transinfected Aedes aegypti mosquitoes possess diverse fitness and vector competence phenotypes.

Science.gov (United States)

Fraser, Johanna E; De Bruyne, Jyotika Taneja; Iturbe-Ormaetxe, Iñaki; Stepnell, Justin; Burns, Rhiannon L; Flores, Heather A; O'Neill, Scott L

2017-12-01

Wolbachia pipientis from Drosophila melanogaster (wMel) is an endosymbiotic bacterium that restricts transmission of human pathogenic flaviviruses and alphaviruses, including dengue, Zika, and chikungunya viruses, when introduced into the mosquito vector Aedes aegypti. To date, wMel-infected Ae. aegypti have been released in field trials in 5 countries to evaluate the effectiveness of this strategy for disease control. Despite the success in establishing wMel-infected mosquitoes in wild populations, and the well-characterized antiviral capabilities of wMel, transinfecting different or additional Wolbachia strains into Ae. aegypti may improve disease impact, and perhaps more importantly, could provide a strategy to account for the possible evolution of resistant arboviruses. Here, we report the successful transinfection of Ae. aegypti with the Wolbachia strains wMelCS (D. melanogaster), wRi (D. simulans) and wPip (Culex quinquefasciatus) and assess the effects on Ae. aegypti fitness, cytoplasmic incompatibility, tissue tropism and pathogen blocking in a laboratory setting. The results demonstrate that wMelCS provides a similar degree of protection against dengue virus as wMel following an infectious blood meal, and significantly reduces viral RNA levels beyond that of wMel following a direct challenge with infectious virus in mosquitoes, with no additional fitness cost to the host. The protection provided by wRi is markedly weaker than that of wMelCS, consistent with previous characterisations of these lines in Drosophila, while wPip was found to substantially reduce the fitness of Ae. aegypti. Thus, we determine wMelCS as a key candidate for further testing in field-relevant fitness tests and viremic blood feeding challenges in a clinical setting to determine if it may represent an alternative Wolbachia strain with more desirable attributes than wMel for future field testing.

Impact of rapid urbanization on mosquitoes and their disease transmission potential in Accra and Tema, Ghana.

Science.gov (United States)

Chinery, W A

1995-06-01

The total of 75 mosquito species recorded in Accra have declined to 28 species. Contributing factors to this decline and the reduction in prevalence of malaria and bancroftian filariasis in Accra presently include extensive water pollution and a fairly high daily mosquito mortality due to several factors including loss of natural adult resting places, use of mosquito repellents and the probable increase of Anopheles arabiensis population. Presently low yellow fever incidence is due inter alia to loss of its feral vectors and reduced intradomiciliary breeding of Aedes aegypti (L) although more common species like A. gambiae s.l., A. aegypti and C. p. quinquefasciatus could between them transmit many other arboviruses. However because of ready availability of human blood, spill-over of viruses from reservoir hosts to man will be rare. Ipso factor, malaria is the most common mosquito-borne disease with centripetal distribution of prevalence.

Composition of human skin microbiota affects attractiveness to malaria mosquitoes.

Directory of Open Access Journals (Sweden)

Niels O Verhulst

Full Text Available The African malaria mosquito Anopheles gambiae sensu stricto continues to play an important role in malaria transmission, which is aggravated by its high degree of anthropophily, making it among the foremost vectors of this disease. In the current study we set out to unravel the strong association between this mosquito species and human beings, as it is determined by odorant cues derived from the human skin. Microbial communities on the skin play key roles in the production of human body odour. We demonstrate that the composition of the skin microbiota affects the degree of attractiveness of human beings to this mosquito species. Bacterial plate counts and 16S rRNA sequencing revealed that individuals that are highly attractive to An. gambiae s.s. have a significantly higher abundance, but lower diversity of bacteria on their skin than individuals that are poorly attractive. Bacterial genera that are correlated with the relative degree of attractiveness to mosquitoes were identified. The discovery of the connection between skin microbial populations and attractiveness to mosquitoes may lead to the development of new mosquito attractants and personalized methods for protection against vectors of malaria and other infectious diseases.

Mosquitoes meet microfluidics: High-throughput microfluidic tools for insect-parasite ecology in field conditions

Science.gov (United States)

Prakash, Manu; Mukundarajan, Haripriya

2013-11-01

A simple bite from an insect is the transmission mechanism for many deadly diseases worldwide--including malaria, yellow fever, west nile and dengue. Very little is known about how populations of numerous insect species and disease-causing parasites interact in their natural habitats due to a lack of measurement techniques. At present, vector surveillance techniques involve manual capture by using humans as live bait, which is hard to justify on ethical grounds. Individual mosquitoes are manually dissected to isolate salivary glands to detect sporozites. With typical vector infection rates being very low even in endemic areas, it is almost impossible to get an accurate picture of disease distribution, in both space and time. Here we present novel high-throughput microfluidic tools for vector surveillance, specifically mosquitoes. A two-dimensional high density array with baits provide an integrated platform for multiplex PCR for detection of both vector and parasite species. Combining techniques from engineering and field ecology, methods and tools developed here will enable high-throughput measurement of infection rates for a number of diseases in mosquito populations in field conditions. Pew Foundation.

Impact of environment on mosquito response to pyrethroid insecticides: facts, evidences and prospects.

Science.gov (United States)

Nkya, Theresia Estomih; Akhouayri, Idir; Kisinza, William; David, Jean-Philippe

2013-04-01

By transmitting major human diseases such as malaria, dengue fever and filariasis, mosquito species represent a serious threat worldwide in terms of public health, and pose a significant economic burden for the African continent and developing tropical regions. Most vector control programmes aiming at controlling life-threatening mosquitoes rely on the use of chemical insecticides, mainly belonging to the pyrethroid class. However, resistance of mosquito populations to pyrethroids is increasing at a dramatic rate, threatening the efficacy of control programmes throughout insecticide-treated areas, where mosquito-borne diseases are still prevalent. In the absence of new insecticides and efficient alternative vector control methods, resistance management strategies are therefore critical, but these require a deep understanding of adaptive mechanisms underlying resistance. Although insecticide resistance mechanisms are intensively studied in mosquitoes, such adaptation is often considered as the unique result of the selection pressure caused by insecticides used for vector control. Indeed, additional environmental parameters, such as insecticides/pesticides usage in agriculture, the presence of anthropogenic or natural xenobiotics, and biotic interactions between vectors and other organisms, may affect both the overall mosquito responses to pyrethroids and the selection of resistance mechanisms. In this context, the present work aims at updating current knowledge on pyrethroid resistance mechanisms in mosquitoes and compiling available data, often from different research fields, on the impact of the environment on mosquito response to pyrethroids. Key environmental factors, such as the presence of urban or agricultural pollutants and biotic interactions between mosquitoes and their microbiome are discussed, and research perspectives to fill in knowledge gaps are suggested. Copyright © 2012 Elsevier Ltd. All rights reserved.

Generation of a Lineage II Powassan Virus (Deer Tick Virus) cDNA Clone: Assessment of Flaviviral Genetic Determinants of Tick and Mosquito Vector Competence.

Science.gov (United States)

Kenney, Joan L; Anishchenko, Michael; Hermance, Meghan; Romo, Hannah; Chen, Ching-I; Thangamani, Saravanan; Brault, Aaron C

2018-05-21

The Flavivirus genus comprises a diverse group of viruses that utilize a wide range of vertebrate hosts and arthropod vectors. The genus includes viruses that are transmitted solely by mosquitoes or vertebrate hosts as well as viruses that alternate transmission between mosquitoes or ticks and vertebrates. Nevertheless, the viral genetic determinants that dictate these unique flaviviral host and vector specificities have been poorly characterized. In this report, a cDNA clone of a flavivirus that is transmitted between ticks and vertebrates (Powassan lineage II, deer tick virus [DTV]) was generated and chimeric viruses between the mosquito/vertebrate flavivirus, West Nile virus (WNV), were constructed. These chimeric viruses expressed the prM and E genes of either WNV or DTV in the heterologous nonstructural (NS) backbone. Recombinant chimeric viruses rescued from cDNAs were characterized for their capacity to grow in vertebrate and arthropod (mosquito and tick) cells as well as for in vivo vector competence in mosquitoes and ticks. Results demonstrated that the NS elements were insufficient to impart the complete mosquito or tick growth phenotypes of parental viruses; however, these NS genetic elements did contribute to a 100- and 100,000-fold increase in viral growth in vitro in tick and mosquito cells, respectively. Mosquito competence was observed only with parental WNV, while infection and transmission potential by ticks were observed with both DTV and WNV-prME/DTV chimeric viruses. These data indicate that NS genetic elements play a significant, but not exclusive, role for vector usage of mosquito- and tick-borne flaviviruses.

The effect of temperature on Anopheles mosquito population dynamics and the potential for malaria transmission.

Directory of Open Access Journals (Sweden)

Lindsay M Beck-Johnson

Full Text Available The parasites that cause malaria depend on Anopheles mosquitoes for transmission; because of this, mosquito population dynamics are a key determinant of malaria risk. Development and survival rates of both the Anopheles mosquitoes and the Plasmodium parasites that cause malaria depend on temperature, making this a potential driver of mosquito population dynamics and malaria transmission. We developed a temperature-dependent, stage-structured delayed differential equation model to better understand how climate determines risk. Including the full mosquito life cycle in the model reveals that the mosquito population abundance is more sensitive to temperature than previously thought because it is strongly influenced by the dynamics of the juvenile mosquito stages whose vital rates are also temperature-dependent. Additionally, the model predicts a peak in abundance of mosquitoes old enough to vector malaria at more accurate temperatures than previous models. Our results point to the importance of incorporating detailed vector biology into models for predicting the risk for vector borne diseases.

Some models for epidemics of vector-transmitted diseases

Directory of Open Access Journals (Sweden)

Fred Brauer

2016-10-01

Full Text Available Vector-transmitted diseases such as dengue fever and chikungunya have been spreading rapidly in many parts of the world. The Zika virus has been known since 1947 and invaded South America in 2013. It can be transmitted not only by (mosquito vectors but also directly through sexual contact. Zika has developed into a serious global health problem because, while most cases are asymptomatic or very light, babies born to Zika - infected mothers may develop microcephaly and other very serious birth defects.We formulate and analyze two epidemic models for vector-transmitted diseases, one appropriate for dengue and chikungunya fever outbreaks and one that includes direct transmission appropriate for Zika virus outbreaks. This is especially important because the Zika virus is the first example of a disease that can be spread both indirectly through a vector and directly (through sexual contact. In both cases, we obtain expressions for the basic reproduction number and show how to use the initial exponential growth rate to estimate the basic reproduction number. However, for the model that includes direct transmission some additional data would be needed to identify the fraction of cases transmitted directly. Data for the 2015 Zika virus outbreak in Barranquilla, Colombia has been used to fit parameters to the model developed here and to estimate the basic reproduction number.

miRNA genes of an invasive vector mosquito, Aedes albopictus.

Directory of Open Access Journals (Sweden)

Jinbao Gu

Full Text Available Aedes albopictus, a vector of Dengue and Chikungunya viruses, is a robust invasive species in both tropical and temperate environments. MicroRNAs (miRNAs regulate gene expression and biological processes including embryonic development, innate immunity and infection. While a number of miRNAs have been discovered in some mosquitoes, no comprehensive effort has been made to characterize them from different developmental stages from a single species. Systematic analysis of miRNAs in Ae. albopictus will improve our understanding of its basic biology and inform novel strategies to prevent virus transmission. Between 10-14 million Illumina sequencing reads per sample were obtained from embryos, larvae, pupae, adult males, sugar-fed and blood-fed adult females. A total of 119 miRNA genes represented by 215 miRNA or miRNA star (miRNA* sequences were identified, 15 of which are novel. Eleven, two, and two of the newly-discovered miRNA genes appear specific to Aedes, Culicinae, and Culicidae, respectively. A number of miRNAs accumulate predominantly in one or two developmental stages and the large number that showed differences in abundance following a blood meal likely are important in blood-induced mosquito biology. Gene Ontology (GO analysis of the targets of all Ae. albopictus miRNAs provides a useful starting point for the study of their functions in mosquitoes. This study is the first systematic analysis of miRNAs based on deep-sequencing of small RNA samples of all developmental stages of a mosquito species. A number of miRNAs are related to specific physiological states, most notably, pre- and post-blood feeding. The distribution of lineage-specific miRNAs is consistent with mosquito phylogeny and the presence of a number of Aedes-specific miRNAs likely reflects the divergence between the Aedes and Culex genera.

Perspectives in the control of infectious diseases by transgenic mosquitoes in the post-genomic era: a review

Directory of Open Access Journals (Sweden)

Márcia Aparecida Sperança

2007-06-01

Full Text Available Arthropod-borne diseases caused by a variety of microorganisms such as dengue virus and malaria parasites afflict billions of people worldwide imposing major economic and social burdens. Despite many efforts, vaccines against diseases transmitted by mosquitoes, with the exception of yellow fever, are not available. Control of such infectious pathogens is mainly performed by vector management and treatment of affected individuals with drugs. However, the numbers of insecticide-resistant insects and drug-resistant parasites are increasing. Therefore, inspired in recent years by a lot of new data produced by genomics and post-genomics research, several scientific groups have been working on different strategies to control infectious arthropod-borne diseases. This review focuses on recent advances and perspectives towards construction of transgenic mosquitoes refractory to malaria parasites and dengue virus transmission.

Perspectives in the control of infectious diseases by transgenic mosquitoes in the post-genomic era--a review.

Science.gov (United States)

Sperança, Márcia Aparecida; Capurro, Margareth Lara

2007-06-01

Arthropod-borne diseases caused by a variety of microorganisms such as dengue virus and malaria parasites afflict billions of people worldwide imposing major economic and social burdens. Despite many efforts, vaccines against diseases transmitted by mosquitoes, with the exception of yellow fever, are not available. Control of such infectious pathogens is mainly performed by vector management and treatment of affected individuals with drugs. However, the numbers of insecticide-resistant insects and drug-resistant parasites are increasing. Therefore, inspired in recent years by a lot of new data produced by genomics and post-genomics research, several scientific groups have been working on different strategies to control infectious arthropod-borne diseases. This review focuses on recent advances and perspectives towards construction of transgenic mosquitoes refractory to malaria parasites and dengue virus transmission.

Current and potential impacts of mosquitoes and the pathogens they vector in the Pacific region

Science.gov (United States)

LaPointe, Dennis

2007-01-01

Mosquitoes and the pathogens they transmit are ubiquitous throughout most of the temperate and tropical regions of the world. The natural and pre-European distribution and diversity of mosquitoes and mosquito-borne diseases throughout much of the Pacific region, however, depicts a depauperate and relatively benign fauna reinforcing the dream of “paradise regained”. In the central and South Pacific few mosquito species were able to colonize the remotest islands and atolls. Native mosquitoes are limited to a few far-ranging species and island endemics are typically restricted to the genera of Aedes and Culex. Only lymphatic filariasis appears to have been present as an endemic mosquito-borne disease before European contact. In nearby Australia, however, some 242 species of mosquitoes are known to occur and more than 70 arboviruses have been identified (Mackenzie 1999). In this regard Australia is more similar to the rest of the tropic and subtropical world than the smaller islands of Oceania. In our ever-shrinking world of global commerce, military activity and travel, the nature of mosquito-borne disease in the Pacific was bound to change. This paper is a brief summary of introduced mosquitoes in the Pacific and their potential impacts on human and wildlife health.

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

Science.gov (United States)

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

Molecular Identification of Vertebrate and Hemoparasite DNA Within Mosquito Blood Meals From Eastern North Dakota

Science.gov (United States)

Vaughan, Jefferson A.

2013-01-01

Abstract To understand local transmission of vector-borne diseases, it is important to identify potential vectors, characterize their host feeding patterns, and determine if vector-borne pathogens are circulating within the region. This study simultaneously investigated these aspects of disease transmission by collecting engorged mosquitoes within two rural study sites in the central Red River Valley of North Dakota. Mosquitoes were identified, midguts were excised, and the blood was expelled from the midguts. DNA was extracted from blood meals and subjected to PCR and direct sequencing to identify the vertebrate origin of the blood. Using different primer sets, PCR was used to screen for two types of vector-borne pathogens, filarioid nematodes and hemosporidian parasites. White-tailed deer were the primary source of blood meals for the eight aedine mosquito species collected. None of the 288 deer-derived blood meals contained filarioid or hemosporidian DNA. In contrast, 18 of 32 Culex tarsalis and three of three Cx. pipiens blood meals contained avian blood, representing eight different species of birds. Of 24 avian-derived blood meals examined, 12 contained Plasmodium DNA, three of which also contained Leucocytozoon DNA (i.e., dual infection). Potential confounding effects resulting from parasite acquisition and development from previous blood meals (e.g., oocysts) were eliminated because host blood had been removed from the midguts prior to DNA extraction. Thus, specific parasite lineages/species could be unequivocally linked to specific vertebrate species. By combining mosquito identification with molecular techniques for identifying blood meal source and pathogens, a relatively small sample of engorged mosquitoes yielded important new information about mosquito feeding patterns and hemosporidia infections in birds. Thorough analyses of wild-caught engorged mosquitoes and other arthropods represent a powerful tool in understanding the local transmission of

Molecular identification of vertebrate and hemoparasite DNA within mosquito blood meals from eastern North Dakota.

Science.gov (United States)

Mehus, Joseph O; Vaughan, Jefferson A

2013-11-01

To understand local transmission of vector-borne diseases, it is important to identify potential vectors, characterize their host feeding patterns, and determine if vector-borne pathogens are circulating within the region. This study simultaneously investigated these aspects of disease transmission by collecting engorged mosquitoes within two rural study sites in the central Red River Valley of North Dakota. Mosquitoes were identified, midguts were excised, and the blood was expelled from the midguts. DNA was extracted from blood meals and subjected to PCR and direct sequencing to identify the vertebrate origin of the blood. Using different primer sets, PCR was used to screen for two types of vector-borne pathogens, filarioid nematodes and hemosporidian parasites. White-tailed deer were the primary source of blood meals for the eight aedine mosquito species collected. None of the 288 deer-derived blood meals contained filarioid or hemosporidian DNA. In contrast, 18 of 32 Culex tarsalis and three of three Cx. pipiens blood meals contained avian blood, representing eight different species of birds. Of 24 avian-derived blood meals examined, 12 contained Plasmodium DNA, three of which also contained Leucocytozoon DNA (i.e., dual infection). Potential confounding effects resulting from parasite acquisition and development from previous blood meals (e.g., oocysts) were eliminated because host blood had been removed from the midguts prior to DNA extraction. Thus, specific parasite lineages/species could be unequivocally linked to specific vertebrate species. By combining mosquito identification with molecular techniques for identifying blood meal source and pathogens, a relatively small sample of engorged mosquitoes yielded important new information about mosquito feeding patterns and hemosporidia infections in birds. Thorough analyses of wild-caught engorged mosquitoes and other arthropods represent a powerful tool in understanding the local transmission of vector

wFlu: characterization and evaluation of a native Wolbachia from the mosquito Aedes fluviatilis as a potential vector control agent.

Directory of Open Access Journals (Sweden)

Luke Anthony Baton

Full Text Available There is currently considerable interest and practical progress in using the endosymbiotic bacteria Wolbachia as a vector control agent for human vector-borne diseases. Such vector control strategies may require the introduction of multiple, different Wolbachia strains into target vector populations, necessitating the identification and characterization of appropriate endosymbiont variants. Here, we report preliminary characterization of wFlu, a native Wolbachia from the neotropical mosquito Aedes fluviatilis, and evaluate its potential as a vector control agent by confirming its ability to cause cytoplasmic incompatibility, and measuring its effect on three parameters determining host fitness (survival, fecundity and fertility, as well as vector competence (susceptibility for pathogen infection. Using an aposymbiotic strain of Ae. fluviatilis cured of its native Wolbachia by antibiotic treatment, we show that in its natural host wFlu causes incomplete, but high levels of, unidirectional cytoplasmic incompatibility, has high rates of maternal transmission, and no detectable fitness costs, indicating a high capacity to rapidly spread through host populations. However, wFlu does not inhibit, and even enhances, oocyst infection with the avian malaria parasite Plasmodium gallinaceum. The stage- and sex-specific density of wFlu was relatively low, and with limited tissue distribution, consistent with the lack of virulence and pathogen interference/symbiont-mediated protection observed. Unexpectedly, the density of wFlu was also shown to be specifically-reduced in the ovaries after bloodfeeding Ae. fluviatilis. Overall, our observations indicate that the Wolbachia strain wFlu has the potential to be used as a vector control agent, and suggests that appreciable mutualistic coevolution has occurred between this endosymbiont and its natural host. Future work will be needed to determine whether wFlu has virulent host effects and/or exhibits pathogen

Identifying the main mosquito species in China based on DNA barcoding.

Directory of Open Access Journals (Sweden)

Gang Wang

Full Text Available Mosquitoes are insects of the Diptera, Nematocera, and Culicidae families, some species of which are important disease vectors. Identifying mosquito species based on morphological characteristics is difficult, particularly the identification of specimens collected in the field as part of disease surveillance programs. Because of this difficulty, we constructed DNA barcodes of the cytochrome c oxidase subunit 1, the COI gene, for the more common mosquito species in China, including the major disease vectors. A total of 404 mosquito specimens were collected and assigned to 15 genera and 122 species and subspecies on the basis of morphological characteristics. Individuals of the same species grouped closely together in a Neighborhood-Joining tree based on COI sequence similarity, regardless of collection site. COI gene sequence divergence was approximately 30 times higher for species in the same genus than for members of the same species. Divergence in over 98% of congeneric species ranged from 2.3% to 21.8%, whereas divergence in conspecific individuals ranged from 0% to 1.67%. Cryptic species may be common and a few pseudogenes were detected.

Operational Mosquito and Vector-Borne Diseases Surveillance at Incirlik Air Base, Turkey

Science.gov (United States)

2017-05-23

of Biological Diversity , Columbus, OH, or the - cies and tested for arboviruses. Pools ranged from 1-25 mosquitoes depending on submission numbers...Rickettsia felis (Rickett- - phonaptera: Pulicidae) in the Philippines . J Ento- mol Sci. 2012;47:95-96. Mosquito surveillance data from Incirlik Air Base...Taylor SJ, Durden LA, Foley EH, Reeves WK. The bat tick Carios azteci (Acari: Argasidae) from Be- lize, with an endosymbiotic Coxiellaceae. Speleo

A survey of basic reproductive ratios in vector-borne disease transmission modeling

Science.gov (United States)

Soewono, E.; Aldila, D.

2015-03-01

Vector-borne diseases are commonly known in tropical and subtropical countries. These diseases have contributed to more than 10% of world infectious disease cases. Among the vectors responsible for transmitting the diseases are mosquitoes, ticks, fleas, flies, bugs and worms. Several of the diseases are known to contribute to the increasing threat to human health such as malaria, dengue, filariasis, chikungunya, west nile fever, yellow fever, encephalistis, and anthrax. It is necessary to understand the real process of infection, factors which contribute to the complication of the transmission in order to come up with a good and sound mathematical model. Although it is not easy to simulate the real transmission process of the infection, we could say that almost all models have been developed from the already long known Host-Vector model. It constitutes the main transmission processes i.e. birth, death, infection and recovery. From this simple model, the basic concepts of Disease Free and Endemic Equilibria and Basic Reproductive Ratio can be well explained and understood. Theoretical, modeling, control and treatment aspects of disease transmission problems have then been developed for various related diseases. General construction as well as specific forms of basic reproductive ratios for vector-borne diseases are discusses here.

Larvicidal Activity of Cassia occidentalis (Linn. against the Larvae of Bancroftian Filariasis Vector Mosquito Culex quinquefasciatus

Directory of Open Access Journals (Sweden)

Deepak Kumar

2014-01-01

Full Text Available Background & Objectives. The plan of this work was to study the larvicidal activity of Cassia occidentalis (Linn. against the larvae of Culex quinquefasciatus. These larvae are the most significant vectors. They transmit the parasites and pathogens which cause a deadly disease like filariasis, dengue, yellow fever, malaria, Japanese encephalitis, chikungunya, and so forth, which are considered harmful towards the population in tropic and subtropical regions. Methods. The preliminary laboratory trail was undertaken to determine the efficacy of petroleum ether and N-butanol extract of dried whole plant of Cassia occidentalis (Linn. belonging to the family Caesalpiniaceae at various concentrations against the late third instar larvae of Culex quinquefasciatus by following the WHO guidelines. Results. The results suggest that 100% mortality effect of petroleum ether and N-butanol extract of Cassia occidentalis (Linn. was observed at 200 and 300 ppm (parts per million. The results obviously showed use of plants in insect control as an alternative method for minimizing the noxious effect of some pesticide compounds on the environment. Thus the extract of Cassia occidentalis (Linn. is claimed as more selective and biodegradable agent. Conclusion. This study justified that plant Cassia occidentalis (Linn. has a realistic mortality result for larvae of filarial vector. This is safe to individual and communities against mosquitoes. It is a natural weapon for mosquito control.

Larvicidal Activity of Cassia occidentalis (Linn.) against the Larvae of Bancroftian Filariasis Vector Mosquito Culex quinquefasciatus.

Science.gov (United States)

Kumar, Deepak; Chawla, Rakesh; Dhamodaram, P; Balakrishnan, N

2014-01-01

Background & Objectives. The plan of this work was to study the larvicidal activity of Cassia occidentalis (Linn.) against the larvae of Culex quinquefasciatus. These larvae are the most significant vectors. They transmit the parasites and pathogens which cause a deadly disease like filariasis, dengue, yellow fever, malaria, Japanese encephalitis, chikungunya, and so forth, which are considered harmful towards the population in tropic and subtropical regions. Methods. The preliminary laboratory trail was undertaken to determine the efficacy of petroleum ether and N-butanol extract of dried whole plant of Cassia occidentalis (Linn.) belonging to the family Caesalpiniaceae at various concentrations against the late third instar larvae of Culex quinquefasciatus by following the WHO guidelines. Results. The results suggest that 100% mortality effect of petroleum ether and N-butanol extract of Cassia occidentalis (Linn.) was observed at 200 and 300 ppm (parts per million). The results obviously showed use of plants in insect control as an alternative method for minimizing the noxious effect of some pesticide compounds on the environment. Thus the extract of Cassia occidentalis (Linn.) is claimed as more selective and biodegradable agent. Conclusion. This study justified that plant Cassia occidentalis (Linn.) has a realistic mortality result for larvae of filarial vector. This is safe to individual and communities against mosquitoes. It is a natural weapon for mosquito control.

Landscape Effects on the Presence, Abundance and Diversity of Mosquitoes in Mediterranean Wetlands.

Directory of Open Access Journals (Sweden)

David Roiz

Full Text Available Environment determines the distribution of mosquito-borne diseases in that it influences the vector-host-pathogen transmission cycle, including vector distribution, abundance and diversity. In this study, we analyse the relationship between environmental variables estimated by remote sensing and the spatial distribution (presence, abundance and diversity of seven mosquito species vectors of West Nile and other pathogens (Usutu, avian malaria and dirofilariasis in the Doñana Natural Park, Spain. Traps were distributed over an area of 54,984 ha divided into six ecological units: marshland, sand dunes, scrubland, ricefields, crops and fishponds. We collected mosquitoes once a month from up to 112 locations using BG-Sentinel traps baited with BG-lure and CO2 during March-November 2010. Hydroperiod, NDVI and Inundation surface were estimated at several resolution scales (100, 250, 500, 1000 and 2000 metres from corrected and normalized Landsat Images. We sampled 972,346 female mosquitoes, the most abundant species being Culex theileri, Ochlerotatus caspius, Culex modestus, Culex perexiguus, Culex pipiens, Anopheles atroparvus and Ochlerotatus detritus. Our results suggest that: (1 hydroperiod, inundation surface and NDVI are strongly related to the spatial distribution of mosquitoes; (2 the spatial scales used to measure these variables affected quantification of these relationships, the larger scale being more informative; (3 these relationships are species-specific; (4 hydroperiod is negatively related to mosquito presence and richness; (5 Culex abundance is positively related to hydroperiod; (6 NDVI is positively related to mosquito diversity, presence and abundance, except in the case of the two salt marsh species (Oc. caspius and Oc. detritus; and (7 inundation surfaces positively condition the abundance and richness of most species except the salt marsh mosquitoes. Remote sensing data provided reliable information for monitoring mosquito

Wolbachia and dengue virus infection in the mosquito Aedes fluviatilis (Diptera: Culicidae.

Directory of Open Access Journals (Sweden)

Jéssica Barreto Lopes Silva

Full Text Available Dengue represents a serious threat to human health, with billions of people living at risk of the disease. Wolbachia pipientis is a bacterial endosymbiont common to many insect species. Wolbachia transinfections in mosquito disease vectors have great value for disease control given the bacterium's ability to spread into wild mosquito populations, and to interfere with infections of pathogens, such as dengue virus. Aedes fluviatilis is a mosquito with a widespread distribution in Latin America, but its status as a dengue vector has not been clarified. Ae. fluviatilis is also naturally infected by the wFlu Wolbachia strain, which has been demonstrated to enhance infection with the avian malarial parasite Plasmodium gallinaceum. We performed experimental infections of Ae. fluviatilis with DENV-2 and DENV-3 isolates from Brazil via injection or oral feeding to provide insight into its competence for the virus. We also examined the effect of the native Wolbachia infection on the virus using a mosquito line where the wFlu infection had been cleared by antibiotic treatment. Through RT-qPCR, we observed that Ae. fluviatilis could become infected with both viruses via either method of infection, although at a lower rate than Aedes aegypti, the primary dengue vector. We then detected DENV-2 and DENV-3 in the saliva of injected mosquitoes, and observed that injection of DENV-3-infected saliva produced subsequent infections in naïve Ae. aegypti. However, across our data we observed no difference in prevalence of infection and viral load between Wolbachia-infected and -uninfected mosquitoes, suggesting that there is no effect of wFlu on dengue virus. Our results highlight that Ae. fluviatilis could potentially serve as a dengue vector under the right circumstances, although further testing is required to determine if this occurs in the field.

Musings on Sketches, Artists, and Mosquito Nets

Centers for Disease Control (CDC) Podcasts

2014-09-23

Byron Breedlove reads his essay Musings on Sketches, Artists, and Mosquito Nets about the art of James Whistler and the transmission of vector borne diseases.  Created: 9/23/2014 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 10/20/2014.

Malaria immunity in man and mosquito: insights into unsolved mysteries of a deadly infectious disease

Science.gov (United States)

Crompton, Peter D.; Moebius, Jacqueline; Portugal, Silvia; Waisberg, Michael; Hart, Geoffrey; Garver, Lindsey S.; Miller, Louis H.; Barillas, Carolina; Pierce, Susan K.

2014-01-01

Malaria is a mosquito-borne disease caused by parasites of the obligate intracellular Apicomplexa family, the most deadly of which, Plasmodium falciparum, prevails in Africa. Malaria imposes a huge health burden on the world’s most vulnerable populations, claiming the lives of nearly a million children and pregnant women each year in Africa alone. Although there is keen interest in eradicating malaria, we do not yet have the necessary tools to meet this challenge, including an effective malaria vaccine and adequate vector control strategies. Here we review what is known about the mechanisms at play in immune resistance to malaria in both the human and mosquito hosts at each step in the parasite’s complex life cycle with a view towards developing the tools that will contribute to the prevention of disease and death and ultimately the goal of malaria eradication. In so doing we hope to inspire immunologists to participate in defeating this devastating disease. PMID:24655294

Understanding the DNA damage response in order to achieve desired gene editing outcomes in mosquitoes.

Science.gov (United States)

Overcash, Justin M; Aryan, Azadeh; Myles, Kevin M; Adelman, Zach N

2015-02-01

Mosquitoes are high-impact disease vectors with the capacity to transmit pathogenic agents that cause diseases such as malaria, yellow fever, chikungunya, and dengue. Continued growth in knowledge of genetic, molecular, and physiological pathways in mosquitoes allows for the development of novel control methods and for the continued optimization of existing ones. The emergence of site-specific nucleases as genomic engineering tools promises to expedite research of crucial biological pathways in these disease vectors. The utilization of these nucleases in a more precise and efficient manner is dependent upon knowledge and manipulation of the DNA repair pathways utilized by the mosquito. While progress has been made in deciphering DNA repair pathways in some model systems, research into the nature of the hierarchy of mosquito DNA repair pathways, as well as in mechanistic differences that may exist, is needed. In this review, we will describe progress in the use of site-specific nucleases in mosquitoes, along with the hierarchy of DNA repair in the context of mosquito chromosomal organization and structure, and how this knowledge may be manipulated to achieve precise chromosomal engineering in mosquitoes.

Climate Chage in Spain and its Influence on Vector-Transmitted Diseases

Directory of Open Access Journals (Sweden)

Andres Iriso Calle

2017-06-01

Full Text Available In the past few decades Spain has experienced a resurgence of some vector-transmitted diseases which were thought to be under control and the appearance of new ones. Likewise, the arrival of new vectors and, in some cases, their establishment and expansion is creating to new public health risks. In general, these phenomena have been associated with complex ecological and climate-driven changes which have favored and increased the densities of vectors and their reservoirs, but they have also been affected by processes that have been triggered or accelerated by man such as globalization, urban development, deforestation and land-use changes.Changes in the distribution of vectors and their capacity to transmit pathogens owing to climate change will become more evident in areas that lie within their distribution limits, as is Spain’s case.This is compounded by Spain’s proximity to Africa and the potential entry of new vectors and pathogens from this continent.This scenario necessitates setting up action programs aimed at both identifying risks posed by vectors and preventing vector-borne diseases, and efficiently managing possible outbreaks that could occur in the future.We have reviewed the scenarios which Spain is expected to experience in connection with climate change and its impact on the incidence of diseases transmitted by mosquitoes, phlebotomine sand flies, ticks and other arthropods, and rodents.

First report of the infection of insecticide-resistant malaria vector mosquitoes with an entomopathogenic fungus under field conditions

Science.gov (United States)

2011-01-01

Background Insecticide-resistant mosquitoes are compromising the ability of current mosquito control tools to control malaria vectors. A proposed new approach for mosquito control is to use entomopathogenic fungi. These fungi have been shown to be lethal to both insecticide-susceptible and insecticide-resistant mosquitoes under laboratory conditions. The goal of this study was to see whether entomopathogenic fungi could be used to infect insecticide-resistant malaria vectors under field conditions, and to see whether the virulence and viability of the fungal conidia decreased after exposure to ambient African field conditions. Methods This study used the fungus Beauveria bassiana to infect the insecticide-resistant malaria vector Anopheles gambiae s.s (Diptera: Culicidae) VKPER laboratory colony strain. Fungal conidia were applied to polyester netting and kept under West African field conditions for varying periods of time. The virulence of the fungal-treated netting was tested 1, 3 and 5 days after net application by exposing An. gambiae s.s. VKPER mosquitoes in WHO cone bioassays carried out under field conditions. In addition, the viability of B. bassiana conidia was measured after up to 20 days exposure to field conditions. Results The results show that B. bassiana infection caused significantly increased mortality with the daily risk of dying being increased by 2.5× for the fungus-exposed mosquitoes compared to the control mosquitoes. However, the virulence of the B. bassiana conidia decreased with increasing time spent exposed to the field conditions, the older the treatment on the net, the lower the fungus-induced mortality rate. This is likely to be due to the climate because laboratory trials found no such decline within the same trial time period. Conidial viability also decreased with increasing exposure to the net and natural abiotic environmental conditions. After 20 days field exposure the conidial viability was 30%, but the viability of control

The potential for flower nectar to allow mosquito to mosquito transmission of Francisella tularensis.

Science.gov (United States)

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.

Taking malaria transmission out of the bottle: implications of mosquito dispersal for vector-control interventions

NARCIS (Netherlands)

Killeen, G.F.; Knols, B.G.J.; Gu, W.D.

2003-01-01

Most malaria transmission models assume enclosed systems of people, parasites, and vectors in which neither emigration nor immigration of mosquitoes is considered. This simplification has facilitated insightful analyses but has substantial limitations for evaluating control measures in the field.

Molecular characterization of larval peripheral thermosensory responses of the malaria vector mosquito Anopheles gambiae.

Directory of Open Access Journals (Sweden)

Chao Liu

Full Text Available Thermosensation provides vital inputs for the malaria vector mosquito, Anopheles gambiae which utilizes heat-sensitivity within a broad spectrum of behaviors, most notably, the localization of human hosts for blood feeding. In this study, we examine thermosensory behaviors in larval-stage An. gambiae, which as a result of their obligate aquatic habitats and importance for vectorial capacity, represents an opportunistic target for vector control as part of the global campaign to eliminate malaria. As is the case for adults, immature mosquitoes respond differentially to a diverse array of external heat stimuli. In addition, larvae exhibit a striking phenotypic plasticity in thermal-driven behaviors that are established by temperature at which embryonic development occurs. Within this spectrum, RNAi-directed gene-silencing studies provide evidence for the essential role of the Transient Receptor Potential sub-family A1 (TRPA1 channel in mediating larval thermal-induced locomotion and thermal preference within a discrete upper range of ambient temperatures.

Identification and analysis of Single Nucleotide Polymorphisms (SNPs in the mosquito Anopheles funestus, malaria vector

Directory of Open Access Journals (Sweden)

Hemingway Janet

2007-01-01

Full Text Available Abstract Background Single nucleotide polymorphisms (SNPs are the most common source of genetic variation in eukaryotic species and have become an important marker for genetic studies. The mosquito Anopheles funestus is one of the major malaria vectors in Africa and yet, prior to this study, no SNPs have been described for this species. Here we report a genome-wide set of SNP markers for use in genetic studies on this important human disease vector. Results DNA fragments from 50 genes were amplified and sequenced from 21 specimens of An. funestus. A third of specimens were field collected in Malawi, a third from a colony of Mozambican origin and a third form a colony of Angolan origin. A total of 494 SNPs including 303 within the coding regions of genes and 5 indels were identified. The physical positions of these SNPs in the genome are known. There were on average 7 SNPs per kilobase similar to that observed in An. gambiae and Drosophila melanogaster. Transitions outnumbered transversions, at a ratio of 2:1. The increased frequency of transition substitutions in coding regions is likely due to the structure of the genetic code and selective constraints. Synonymous sites within coding regions showed a higher polymorphism rate than non-coding introns or 3' and 5'flanking DNA with most of the substitutions in coding regions being observed at the 3rd codon position. A positive correlation in the level of polymorphism was observed between coding and non-coding regions within a gene. By genotyping a subset of 30 SNPs, we confirmed the validity of the SNPs identified during this study. Conclusion This set of SNP markers represents a useful tool for genetic studies in An. funestus, and will be useful in identifying candidate genes that affect diverse ranges of phenotypes that impact on vector control, such as resistance insecticide, mosquito behavior and vector competence.

Transmission of Rift Valley fever virus from European-breed lambs to Culex pipiens mosquitoes.

Directory of Open Access Journals (Sweden)

Rianka P M Vloet

2017-12-01

Full Text Available Rift Valley fever virus (RVFV is a mosquito-borne bunyavirus of the genus Phlebovirus that is highly pathogenic to ruminants and humans. The disease is currently confined to Africa and the Arabian Peninsula, but globalization and climate change may facilitate introductions of the virus into currently unaffected areas via infected animals or mosquitoes. The consequences of such an introduction will depend on environmental factors, the availability of susceptible ruminants and the capacity of local mosquitoes to transmit the virus. We have previously demonstrated that lambs native to the Netherlands are highly susceptible to RVFV and we here report the vector competence of Culex (Cx. pipiens, the most abundant and widespread mosquito species in the country. Vector competence was first determined after artificial blood feeding of laboratory-reared mosquitoes using the attenuated Clone 13 strain. Subsequently, experiments with wild-type RVFV and mosquitoes hatched from field-collected eggs were performed. Finally, the transmission of RVFV from viremic lambs to mosquitoes was studied.Artificial feeding experiments using Clone 13 demonstrated that indigenous, laboratory-reared Cx. pipiens mosquitoes are susceptible to RVFV and that the virus can be transmitted via their saliva. Experiments with wild-type RVFV and mosquitoes hatched from field-collected eggs confirmed the vector competence of Cx. pipiens mosquitoes from the Netherlands. To subsequently investigate transmission of the virus under more natural conditions, mosquitoes were allowed to feed on RVFV-infected lambs during the viremic period. We found that RVFV is efficiently transmitted from lambs to mosquitoes, although transmission was restricted to peak viremia. Interestingly, in the mosquito-exposed skin samples, replication of RVFV was detected in previously unrecognized target cells.We here report the vector competence of Cx. pipiens mosquitoes from the Netherlands for RVFV. Both

The Dengue Virus Mosquito Vector Aedes aegypti at High Elevation in México

Science.gov (United States)

Lozano-Fuentes, Saul; Hayden, Mary H.; Welsh-Rodriguez, Carlos; Ochoa-Martinez, Carolina; Tapia-Santos, Berenice; Kobylinski, Kevin C.; Uejio, Christopher K.; Zielinski-Gutierrez, Emily; Monache, Luca Delle; Monaghan, Andrew J.; Steinhoff, Daniel F.; Eisen, Lars

2012-01-01

México has cities (e.g., México City and Puebla City) located at elevations > 2,000 m and above the elevation ceiling below which local climates allow the dengue virus mosquito vector Aedes aegypti to proliferate. Climate warming could raise this ceiling and place high-elevation cities at risk for dengue virus transmission. To assess the elevation ceiling for Ae. aegypti and determine the potential for using weather/climate parameters to predict mosquito abundance, we surveyed 12 communities along an elevation/climate gradient from Veracruz City (sea level) to Puebla City (∼2,100 m). Ae. aegypti was commonly encountered up to 1,700 m and present but rare from 1,700 to 2,130 m. This finding extends the known elevation range in México by > 300 m. Mosquito abundance was correlated with weather parameters, including temperature indices. Potential larval development sites were abundant in Puebla City and other high-elevation communities, suggesting that Ae. aegypti could proliferate should the climate become warmer. PMID:22987656

Imaginal Discs ? A New Source of Chromosomes for Genome Mapping of the Yellow Fever Mosquito Aedes aegypti

OpenAIRE

Sharakhova, Maria V.; Timoshevskiy, Vladimir A.; Yang, Fan; Demin, Sergei Iu.; Severson, David W.; Sharakhov, Igor V.

2011-01-01

Author Summary Dengue fever is an emerging health threat to as much as half of the human population around the world. No vaccines or drug treatments are currently available. Thus, disease prevention is largely based on efforts to control its major mosquito vector Ae. aegypti. Novel vector control strategies, such as population replacement with pathogen-incompetent transgenic mosquitoes, rely on detailed knowledge of the genome organization for the mosquito. However, the current genome assembl...

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

Science.gov (United States)

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.

Detection and identification of Rift Valley fever virus in mosquito vectors by quantitative real-time PCR.

Science.gov (United States)

Mwaengo, D; Lorenzo, G; Iglesias, J; Warigia, M; Sang, R; Bishop, R P; Brun, A

2012-10-01

Diagnostic methods allowing for rapid identification of pathogens are crucial for controlling and preventing dissemination after disease outbreaks as well as for use in surveillance programs. For arboviruses, detection of the presence of virus in their arthropod hosts is important for monitoring of viral activity and quantitative information is useful for modeling of transmission dynamics. In this study, molecular detection of Rift Valley fever virus (RVFV) in mosquito samples from the 2006 to 2007 East African outbreaks was performed using quantitative real-time PCR assay (qRT-PCR). Specific RVFV sequence-based primer/fluorogenic (TaqMan) probe sets were derived from the L and S RNA segments of the virus. Both primer-probe L and S segment-based combinations detected genomic RVFV sequences, with generally comparable levels of sensitivity. Viral loads from three mosquito species, Aedes mcintoshi, Aedes ochraceus and Mansonia uniformis were estimated and significant differences of between 5- and 1000-fold were detected between Ae. mcintoshi and M. uniformis using both the L and S primer-probe-based assays. The genetic relationships of the viral sequences in mosquito samples were established by partial M segment sequencing and assigned to the two previously described viral lineages defined by analysis of livestock isolates obtained during the 2006-2007 outbreak, confirming that similar viruses were present in both the vector and mammalian host. The data confirms the utility of qRT-PCR for identification and initial quantification of virus in mosquito samples during RVFV outbreaks. Copyright © 2012 Elsevier B.V. All rights reserved.

West Nile Virus in Mosquitoes of Iranian Wetlands.

Science.gov (United States)

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.

Efficacy of Advanced Odomos repellent cream (N, N-diethyl-benzamide) against mosquito vectors.

Science.gov (United States)

Mittal, P K; Sreehari, U; Razdan, R K; Dash, A P; Ansari, M A

2011-04-01

Repellents are commonly used personal protection measures to avoid mosquito bites. In the present study, Advanced Odomos cream (12% N, N-diethyl-benzamide) was tested for its efficacy against mosquitoes in comparison to DEET (N,N-diethyl-3-methyl benzamide). Bioassays were conducted to assess the repellency of Advanced Odomos and DEET creams against Anopheles stephensi and Aedes aegypti. Their efficacy was tested on human volunteers applied with different concentrations of test creams ranging from 1 to 12 mg/cm 2 and by exposing them to mosquitoes at hourly intervals. Field evaluation was also carried out to test the duration of protection of the test creams against Anopheles and Aedes mosquitoes during whole night and day time collections, respectively on human volunteers. Mosquito collections were done using torch light and aspirator. Complete (100%) protection was achieved at 10 mg/cm 2 cream formulation of Advanced Odomos (1.2 mg a.i/cm 2 ) dose against An. stephensi and 12 mg/cm 2 (1.44 mg a.i./cm 2 ) against Ae. aegypti on human baits. There was no statistically significant differences in per cent protection against mosquito bites between Advanced Odomos and DEET cream (P>0.05) in respective doses. Complete protection up to 11 h was observed against Anopheles mosquitoes during whole night collections and up to 6 h against Ae. aegypti in day time collections. No adverse reactions such as itching, irritation, vomiting, nausea, etc. were reported by the volunteers. Advanced Odomos cream applied at 10 mg/cm 2 concentration provided 100% protection from Anopheles mosquitoes up to 11 h whereas about 6 h protection was recorded against Ae. aegypti. The laboratory and field trials indicate that for longer protection against Anopheles mosquitoes 10 mg/cm 2 will be appropriate and in case of Ae. aegypti more than 10 mg/cm 2 application is required for complete protection. In conclusion, the Advanced Odomos cream was comparable to the known repellent cream DEET for

Green synthesized nanoparticles in the fight against mosquito-borne diseases and cancer-a brief review.

Science.gov (United States)

Benelli, Giovanni

2016-12-01

Nanobiomedicine and parasitology are facing a number of key challenges, which mostly deal with the paucity of effective preventive and curative tools against mosquito-borne diseases and cancer. In this scenario, the employ of botanical and invertebrate extracts as reducing, stabilizing and capping agents for the synthesis of nanoparticles is advantageous over chemical and physical methods, since it is one-pot, cheap, and does not require high pressure, energy, temperature, or the use of highly toxic chemicals. Considering the overlooked connection between mosquito vector activity and the spread of cancer in USA, this review focused on the current knowledge available about green synthesized nanoparticles with efficacy against mosquito-borne diseases and cancer. Green fabricated metal nanoparticles showed antiplasmodial activity that often encompasses the efficacy of currently marked drugs for malaria treatment. They have been also reported as growth inhibitors against dengue virus (serotype DEN-2), with moderate cytotoxicity on mammalian cells. However, this feature is strongly dependent to the botanical agents employed during nanosynthesis. In addition, green nanoparticles have been successfully used to reduce mosquito young instar populations in the field. The final section focuses on some issues for future research, with special reference to the chemical standardization of the botanical extracts used for nanosynthesis and the potential effects on green fabricated nanoparticles on non-target organisms. Copyright © 2016 Elsevier Inc. All rights reserved.

Evolution determines how global warming and pesticide exposure will shape predator‐prey interactions with vector mosquitoes

DEFF Research Database (Denmark)

Tran, Tam H.; Janssens, Lizanne; Dinh, Khuong Van

2016-01-01

How evolution may mitigate the effects of global warming and pesticide exposure on predator–prey interactions is directly relevant for vector control. Using a space-for-time substitution approach, we addressed how 4°C warming and exposure to the pesticide endosulfan shape the predation on Culex...... pipiens mosquitoes by damselfly predators from replicated low- and high-latitude populations. Although warming was only lethal for the mosquitoes, it reduced predation rates on these prey. Possibly, under warming escape speeds of the mosquitoes increased more than the attack efficiency of the predators...... at the high latitude will be reduced under warming unless predators evolve toward the current low-latitude phenotype or low-latitude predators move poleward...

The potential for flower nectar to allow mosquito to mosquito transmission of Francisella tularensis.

Directory of Open Access Journals (Sweden)

Adam Kenney

Full Text Available 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.

Discovery of Novel Viruses in Mosquitoes from the Zambezi Valley of Mozambique.

Directory of Open Access Journals (Sweden)

Harindranath Cholleti

Full Text Available Mosquitoes carry a wide variety of viruses that can cause vector-borne infectious diseases and affect both human and veterinary public health. Although Mozambique can be considered a hot spot for emerging infectious diseases due to factors such as a rich vector population and a close vector/human/wildlife interface, the viral flora in mosquitoes have not previously been investigated. In this study, viral metagenomics was employed to analyze the viral communities in Culex and Mansonia mosquitoes in the Zambezia province of Mozambique. Among the 1.7 and 2.6 million sequences produced from the Culex and Mansonia samples, respectively, 3269 and 983 reads were classified as viral sequences. Viruses belonging to the Flaviviridae, Rhabdoviridae and Iflaviridae families were detected, and different unclassified single- and double-stranded RNA viruses were also identified. A near complete genome of a flavivirus, tentatively named Cuacua virus, was obtained from the Mansonia mosquitoes. Phylogenetic analysis of this flavivirus, using the NS5 amino acid sequence, showed that it grouped with 'insect-specific' viruses and was most closely related to Nakiwogo virus previously identified in Uganda. Both mosquito genera had viral sequences related to Rhabdoviruses, and these were most closely related to Culex tritaeniorhynchus rhabdovirus (CTRV. The results from this study suggest that several viruses specific for insects belonging to, for example, the Flaviviridae and Rhabdoviridae families, as well as a number of unclassified RNA viruses, are present in mosquitoes in Mozambique.

Vector-borne Infections

Centers for Disease Control (CDC) Podcasts

2011-04-18

This podcast discusses emerging vector-borne pathogens, their role as prominent contributors to emerging infectious diseases, how they're spread, and the ineffectiveness of mosquito control methods.  Created: 4/18/2011 by National Center for Emerging Zoonotic and Infectious Diseases (NCEZID).   Date Released: 4/27/2011.

Evolution determines how global warming and pesticide exposure will shape predator-prey interactions with vector mosquitoes.

Science.gov (United States)

Tran, Tam T; Janssens, Lizanne; Dinh, Khuong V; Op de Beeck, Lin; Stoks, Robby

2016-07-01

How evolution may mitigate the effects of global warming and pesticide exposure on predator-prey interactions is directly relevant for vector control. Using a space-for-time substitution approach, we addressed how 4°C warming and exposure to the pesticide endosulfan shape the predation on Culex pipiens mosquitoes by damselfly predators from replicated low- and high-latitude populations. Although warming was only lethal for the mosquitoes, it reduced predation rates on these prey. Possibly, under warming escape speeds of the mosquitoes increased more than the attack efficiency of the predators. Endosulfan imposed mortality and induced behavioral changes (including increased filtering and thrashing and a positional shift away from the bottom) in mosquito larvae. Although the pesticide was only lethal for the mosquitoes, it reduced predation rates by the low-latitude predators. This can be explained by the combination of the evolution of a faster life history and associated higher vulnerabilities to the pesticide (in terms of growth rate and lowered foraging activity) in the low-latitude predators and pesticide-induced survival selection in the mosquitoes. Our results suggest that predation rates on mosquitoes at the high latitude will be reduced under warming unless predators evolve toward the current low-latitude phenotype or low-latitude predators move poleward.

Landscape variation influences trophic cascades in dengue vector food webs.

Science.gov (United States)

Weterings, Robbie; Umponstira, Chanin; Buckley, Hannah L

2018-02-01

The epidemiology of vector-borne diseases is governed by a structured array of correlative and causative factors, including landscape (for example, rural versus urban), abiotic (for example, weather), and biotic (for example, food web) factors. Studies of mosquito-borne diseases rarely address these multiple factors at large spatial scales, which limits insights into how human alterations of landscapes and food webs alter mosquito abundance. We used structural equation modeling to identify the relative magnitude and direction of landscape, abiotic, and food web factors on Aedes larvae and adults across 70 sites in northern Thailand. Food web factors were modeled as mosquito-predator trophic cascades. Landscape context affected mosquito-predator communities in aquatic and terrestrial environments via cascading food web interactions. Several mosquito predators within these food webs showed potential as biocontrol agents in mosquito population control, but their potentials for control were landscape-dependent. In terrestrial food webs, the habitat-sensitive tokay gecko structured mosquito-predator communities, indicating that a conservation approach to vector control could be a useful addition to existing control efforts.

Polyphenol-Rich Diets Exacerbate AMPK-Mediated Autophagy, Decreasing Proliferation of Mosquito Midgut Microbiota, and Extending Vector Lifespan.

Directory of Open Access Journals (Sweden)

Rodrigo Dutra Nunes

2016-10-01

Full Text Available Mosquitoes feed on plant-derived fluids such as nectar and sap and are exposed to bioactive molecules found in this dietary source. However, the role of such molecules on mosquito vectorial capacity is unknown. Weather has been recognized as a major determinant of the spread of dengue, and plants under abiotic stress increase their production of polyphenols.Here, we show that including polyphenols in mosquito meals promoted the activation of AMP-dependent protein kinase (AMPK. AMPK positively regulated midgut autophagy leading to a decrease in bacterial proliferation and an increase in vector lifespan. Suppression of AMPK activity resulted in a 6-fold increase in midgut microbiota. Similarly, inhibition of polyphenol-induced autophagy induced an 8-fold increase in bacterial proliferation. Mosquitoes maintained on the polyphenol diet were readily infected by dengue virus.The present findings uncover a new direct route by which exacerbation of autophagy through activation of the AMPK pathway leads to a more efficient control of mosquito midgut microbiota and increases the average mosquito lifespan. Our results suggest for the first time that the polyphenol content and availability of the surrounding vegetation may increase the population of mosquitoes prone to infection with arboviruses.

Improving vector-borne pathogen surveillance: A laboratory-based study exploring the potential to detect dengue virus and malaria parasites in mosquito saliva.

Science.gov (United States)

Melanson, Vanessa R; Jochim, Ryan; Yarnell, Michael; Ferlez, Karen Bingham; Shashikumar, Soumya; Richardson, Jason H

2017-01-01

Vector-borne pathogen surveillance programmes typically rely on the collection of large numbers of potential vectors followed by screening protocols focused on detecting pathogens in the arthropods. These processes are laborious, time consuming, expensive, and require screening of large numbers of samples. To streamline the surveillance process, increase sample throughput, and improve cost-effectiveness, a method to detect dengue virus and malaria parasites (Plasmodium falciparum) by leveraging the sugar-feeding behaviour of mosquitoes and their habit of expectorating infectious agents in their saliva during feeding was investigated in this study. Dengue virus 2 (DENV-2) infected female Aedes aegypti mosquitoes and P. falciparum infected female Anopheles stephensi mosquitoes were allowed to feed on honey coated Flinders Technical Associates -FTA® cards dyed with blue food colouring. The feeding resulted in deposition of saliva containing either DENV-2 particles or P. falciparum sporozoites onto the FTA card. Nucleic acid was extracted from each card and the appropriate real-time PCR (qPCR) assay was run to detect the pathogen of interest. As little as one plaque forming unit (PFU) of DENV-2 and as few as 60 P. falciparum parasites deposited on FTA cards from infected mosquitoes were detected via qPCR. Hence, their use to collect mosquito saliva for pathogen detection is a relevant technique for vector surveillance. This study provides laboratory confirmation that FTA cards can be used to capture and stabilize expectorated DENV-2 particles and P. falciparum sporozoites from infectious, sugar-feeding mosquitoes in very low numbers. Thus, the FTA card-based mosquito saliva capture method offers promise to overcome current limitations and revolutionize traditional mosquito-based pathogen surveillance programmes. Field testing and further method development are required to optimize this strategy.

Mapping of courses on vector biology and vector-borne diseases systems: time for a worldwide effort

Science.gov (United States)

Casas, Jérôme; Lazzari, Claudio; Insausti, Teresita; Launois, Pascal; Fouque, Florence

2016-01-01

Major emergency efforts are being mounted for each vector-borne disease epidemiological crisis anew, while knowledge about the biology of arthropods vectors is dwindling slowly but continuously, as is the number of field entomologists. The discrepancy between the rates of production of knowledge and its use and need for solving crises is widening, in particular due to the highly differing time spans of the two concurrent processes. A worldwide web based search using multiple key words and search engines of onsite and online courses in English, Spanish, Portuguese, French, Italian and German concerned with the biology of vectors identified over 140 courses. They are geographically and thematically scattered, the vast majority of them are on-site, with very few courses using the latest massive open online course (MOOC) powerfulness. Over two third of them is given in English and Western Africa is particularity poorly represented. The taxonomic groups covered are highly unbalanced towards mosquitoes. A worldwide unique portal to guide students of all grades and levels of expertise, in particular those in remote locations, is badly needed. This is the objective a new activity supported by the Special Programme for Research and Training in Tropical Diseases (TDR). PMID:27759770

Acoustic communication in insect disease vectors

Directory of Open Access Journals (Sweden)

Felipe de Mello Vigoder

2013-01-01

Full Text Available Acoustic signalling has been extensively studied in insect species, which has led to a better understanding of sexual communication, sexual selection and modes of speciation. The significance of acoustic signals for a blood-sucking insect was first reported in the XIX century by Christopher Johnston, studying the hearing organs of mosquitoes, but has received relatively little attention in other disease vectors until recently. Acoustic signals are often associated with mating behaviour and sexual selection and changes in signalling can lead to rapid evolutionary divergence and may ultimately contribute to the process of speciation. Songs can also have implications for the success of novel methods of disease control such as determining the mating competitiveness of modified insects used for mass-release control programs. Species-specific sound “signatures” may help identify incipient species within species complexes that may be of epidemiological significance, e.g. of higher vectorial capacity, thereby enabling the application of more focussed control measures to optimise the reduction of pathogen transmission. Although the study of acoustic communication in insect vectors has been relatively limited, this review of research demonstrates their value as models for understanding both the functional and evolutionary significance of acoustic communication in insects.

Gene Drive for Mosquito Control: Where Did It Come from and Where Are We Headed?

Science.gov (United States)

Macias, Vanessa M; Ohm, Johanna R; Rasgon, Jason L

2017-09-02

Mosquito-borne pathogens place an enormous burden on human health. The existing toolkit is insufficient to support ongoing vector-control efforts towards meeting disease elimination and eradication goals. The perspective that genetic approaches can potentially add a significant set of tools toward mosquito control is not new, but the recent improvements in site-specific gene editing with CRISPR/Cas9 systems have enhanced our ability to both study mosquito biology using reverse genetics and produce genetics-based tools. Cas9-mediated gene-editing is an efficient and adaptable platform for gene drive strategies, which have advantages over innundative release strategies for introgressing desirable suppression and pathogen-blocking genotypes into wild mosquito populations; until recently, an effective gene drive has been largely out of reach. Many considerations will inform the effective use of new genetic tools, including gene drives. Here we review the lengthy history of genetic advances in mosquito biology and discuss both the impact of efficient site-specific gene editing on vector biology and the resulting potential to deploy new genetic tools for the abatement of mosquito-borne disease.

Review: artificial container-breeding mosquitoes and cemeteries: a perfect match.

Science.gov (United States)

Vezzani, Darío

2007-02-01

Artificial container-breeding mosquitoes, such as Aedes aegypti, Ae. albopictus, and Culex pipiens, are well-recognized vectors of diseases throughout the world. Cemeteries are considered major sources of mosquitoes and the results of more than 30 studies concerning mosquitoes in cemeteries have been published over the last decade. The characteristics of these environments in regard to the availability of resources for mosquito development were discussed. Also, studies about early detection of Aedes vectors, ecological issues, and mosquito control performed in cemeteries were reviewed. Among 31 mosquito species found breeding in cemeteries from 16 countries, the invasive Ae. aegypti and Ae. albopictus were the most frequent ones. Species of the genus Ochlerotatus, Culex, Toxorhynchites, Culiseta, Armigeres, Lutzia, Uranotaenia, and Tripteroides were also reported. Overall, cemeteries are highly suitable habitats for artificial container-breeding mosquitoes due to the great availability of the different resources that they need (i.e. sugar substances, blood, shelter and water-filled containers). In addition, these places are mostly ideal settings to perform studies in urbanized areas because of high mosquito abundance, heterogeneity of macro- and microhabitats, and an easier access in comparison with private premises. However, the feasibility of a cemetery as a study area must be evaluated in each case considering the objectives of the study and cemetery characteristics.

EPA-Registered Repellents for Mosquitoes Transmitting Emerging Viral Disease.

Science.gov (United States)

Patel, Radha V; Shaeer, Kristy M; Patel, Pooja; Garmaza, Aleksey; Wiangkham, Kornwalee; Franks, Rachel B; Pane, Olivia; Carris, Nicholas W

2016-12-01

In many parts of the United States, mosquitoes were previously nuisance pests. However, they now represent a potential threat in the spread of viral diseases. The Aedes aegypti, Aedes albopictus, and Culex species mosquitoes are endemic to the United States and together may transmit a variety of viral diseases of growing concern, including West Nile virus, chikungunya, dengue fever, and Zika virus. The Centers for Disease Control and Prevention and the Environmental Protection Agency (EPA) recommend N,N-diethyl-meta-toluamide (DEET) as a first-line mosquito repellent, but for patients refusing to use DEET or other conventional repellents, guidance is limited to any EPA-registered product. Therefore, we conducted a systematic review of the literature to identify which EPA-registered personal mosquito repellent provides the best protection from A. aegypti, A. albopictus, and Culex spp. mosquitoes. We abstracted data from 62 published reports of EPA-registered mosquito repellents. The conventional repellent picaridin has the strongest data to support its use as a second-line agent, while IR3535 and oil of lemon eucalyptus are reasonably effective natural products. Citronella, catnip, and 2-undecanone offer limited protection or have limited data. These results can be used by pharmacists and other health care professionals to advise patients on the selection of an EPA-registered mosquito repellent. Regardless of the repellent chosen, it is vital for patients to follow all instructions/precautions in the product labeling to ensure safe and effective use. © 2016 Pharmacotherapy Publications, Inc.

Mosquitos transgênicos para o controle da malária: progressos e desafios

OpenAIRE

Moreira, Luciano A.; Jacobs-Lorena, Marcelo

2003-01-01

Malaria kills millions of people every year and the current strategies to control the disease, such as insecticides and drugs have not been completely efficient. Because of that, novel means to fight against malaria are of utmost importance. Advances in the study of the mosquito vector and its interactions with the malaria parasite made scientists think that it is possible to genetically manipulate the mosquitoes to make them inefficient vectors. Here we review the advances on the introductio...

Environmental and social-demographic predictors of the southern house mosquito Culex quinquefasciatus in New Orleans, Louisiana.

Science.gov (United States)

Moise, Imelda K; Riegel, Claudia; Muturi, Ephantus J

2018-04-17

Understanding the major predictors of disease vectors such as mosquitoes can guide the development of effective and timely strategies for mitigating vector-borne disease outbreaks. This study examined the influence of selected environmental, weather and sociodemographic factors on the spatial and temporal distribution of the southern house mosquito Culex quinquefasciatus Say in New Orleans, Louisiana, USA. Adult mosquitoes were collected over a 4-year period (2006, 2008, 2009 and 2010) using CDC gravid traps. Socio-demographic predictors were obtained from the United States Census Bureau, 2005-2009 American Community Survey and the City of New Orleans Department of Code Enforcement. Linear mixed effects models and ERDAS image processing software were used for statistical analysis and image processing. Only two of the 22 predictors examined were significant predictors of Cx. quinquefasciatus abundance. Mean temperature during the week of mosquito collection was positively associated with Cx. quinquefasciatus abundance while developed high intensity areas were negatively associated with Cx. quinquefasciatus abundance. The findings of this study illustrate the power and utility of integrating biophysical and sociodemographic data using GIS analysis to identify the biophysical and sociodemographic processes that increase the risk of vector mosquito abundance. This knowledge can inform development of accurate predictive models that ensure timely implementation of mosquito control interventions.

Chemosensory responses to the repellent nepeta essential oil and its major component nepetalactone by the yellow fever mosquito, aedes aegypti, a vector of zika virus

Science.gov (United States)

Nepeta essential oil (Neo) (catnip) and its major component, nepetalactone, have long been known to repel insects including mosquitoes. However, the neural mechanisms through which these repellents are detected by mosquitoes, including the yellow fever mosquito Aedes aegypti, an important vector of...

Current vector control challenges in the fight against malaria.

Science.gov (United States)

Benelli, Giovanni; Beier, John C

2017-10-01

The effective and eco-friendly control of Anopheles vectors plays a key role in any malaria management program. Integrated Vector Management (IVM) suggests making use of the full range of vector control tools available. The strategies for IVM require novel technologies to control outdoor transmission of malaria. Despite the wide number of promising control tools tested against mosquitoes, current strategies for malaria vector control used in most African countries are not sufficient to achieve successful malaria control. The majority of National Malaria Control Programs in Africa still rely on indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs). These methods reduce malaria incidence but generally have little impact on malaria prevalence. In addition to outdoor transmission, growing levels of insecticide resistance in targeted vectors threaten the efficacy of LLINs and IRS. Larvicidal treatments can be useful, but are not recommended for rural areas. The research needed to improve the quality and delivery of mosquito vector control should focus on (i) optimization of processes and methods for vector control delivery; (ii) monitoring of vector populations and biting activity with reliable techniques; (iii) the development of effective and eco-friendly tools to reduce the burden or locally eliminate malaria and other mosquito-borne diseases; (iv) the careful evaluation of field suitability and efficacy of new mosquito control tools to prove their epidemiological impact; (v) the continuous monitoring of environmental changes which potentially affect malaria vector populations; (vi) the cooperation among different disciplines, with main emphasis on parasitology, tropical medicine, ecology, entomology, and ecotoxicology. A better understanding of behavioral ecology of malaria vectors is required. Key ecological obstacles that limit the effectiveness of vector control include the variation in mosquito behavior, development of insecticide resistance

Emerging mosquito species in Germany-a synopsis after 6 years of mosquito monitoring (2011-2016).

Science.gov (United States)

Kampen, Helge; Schuhbauer, Astrid; Walther, Doreen

2017-12-01

Globalisation and climate change are the main drivers of invasion of non-endemic regions by mosquitoes. Mass transportation of people, animals and goods facilitate accidental long-distance displacement while climate warming supports active spread and establishment of thermophilic species. In the framework of a mosquito-monitoring programme, eight non-indigenous culicid species have been registered in Germany since 2011, with four of them being more or less efficient vectors of disease agents and another four now considered established. The eight newly emerged species include Aedes albopictus, Ae. japonicus, Ae. aegypti, Ae. koreicus, Ae. berlandi, Ae. pulcritarsis, Anopheles petragnani and Culiseta longiareolata. We here review recent findings and at the same time present new findings of specimens of non-native mosquito species in Germany.

Newer Vaccines against Mosquito-borne Diseases.

Science.gov (United States)

Aggarwal, Anju; Garg, Neha

2018-02-01

Mosquitos are responsible for a number of protozoal and viral diseases. Malaria, dengue, Japanese encephalitis (JE) and chikungunya epidemics occur commonly all over the world, leading to marked mortality and morbidity in children. Zika, Yellow fever and West Nile fever are others requiring prevention. Environmental control and mosquito bite prevention are useful in decreasing the burden of disease but vaccination has been found to be most cost-effective and is the need of the hour. RTS,S/AS01 vaccine is the first malaria vaccine being licensed for use against P. falciparum malaria. Dengvaxia (CYD-TDV) against dengue was licensed first in Mexico in 2015. A Vero-cell derived, inactivated and alum-adjuvanted JE vaccine based on the SA14-14-2 strain was approved in 2009 in North America, Australia and various European countries. It can be used from 2 mo of age. In India, immunization is carried out in endemic regions at 1 y of age. Another inactivated Vero-cell culture derived Kolar strain, 821564XY, JE vaccine is being used in India. Candidate vaccines against dengue, chikungunya and West Nile fever are been discussed. A continued research and development of new vaccines are required for controlling these mosquito-borne diseases.

Mecanismos de invasión del esporozoíto de Plasmodium en el mosquito vector Anopheles

Directory of Open Access Journals (Sweden)

Lilian M. Spencer

2016-09-01

Full Text Available La Malaria o Paludismo es una de las enfermedades tropicales considerada un problema de salud pública a nivel mundial por la OMS. Plasmodium es un protozoario cuyo vector es la hembra del mosquito Anopheles. En este vector se cumplen dos procesos fundamentales en el ciclo de vida del parásito, como son la reproducción sexual, con la formación de un cigoto móvil llamado ooquineto como producto de la fertilización entre los gametos; y la invasión del epitelio del estómago y formación del ooquiste. El estadio producto de esta esporogonia son los esporozoítos (reproducción asexual que se dirigen a las glándulas salivales; y es el infectivo para el mamífero. El esporozoíto es el responsable de establecer la enfermedad en su hospedador vertebrado y por lo tanto los procesos de invasión de este a las glándulas salivales del mosquito es uno de los puntos fundamentales de estudio. Nosotros presentamos una revisión acerca de los mecanismos de invasión del parásito dentro del vector mosquito y las proteínas más importantes que median este proceso. Uno de los aspectos más estudiados en las investigaciones en malaria ha sido determinar la antigenicidad de dichas proteínas en esta parte del ciclo con el fin de ser usadas en el diseño de vacunas. Entre ellas, algunas de las más estudiadas son: P230, P48/45, P28, P25, CTRP, CS, TRAP, WARP y SOAP las cuales han sido consideradas en las estrategias para inhibir el desarrollo del parásito, mejor conocidas como vacunas de bloqueo de trasmisión por el vector. Por lo tanto, presentamos algunas de las estrategias en el diseño de vacunas, basado en las proteínas implicadas en los estadios desarrollados dentro del vector.

Wolbachia enhances West Nile virus (WNV infection in the mosquito Culex tarsalis.

Directory of Open Access Journals (Sweden)

Brittany L Dodson

2014-07-01

Full Text Available Novel strategies are required to control mosquitoes and the pathogens they transmit. One attractive approach involves maternally inherited endosymbiotic Wolbachia bacteria. After artificial infection with Wolbachia, many mosquitoes become refractory to infection and transmission of diverse pathogens. We evaluated the effects of Wolbachia (wAlbB strain on infection, dissemination and transmission of West Nile virus (WNV in the naturally uninfected mosquito Culex tarsalis, which is an important WNV vector in North America. After inoculation into adult female mosquitoes, Wolbachia reached high titers and disseminated widely to numerous tissues including the head, thoracic flight muscles, fat body and ovarian follicles. Contrary to other systems, Wolbachia did not inhibit WNV in this mosquito. Rather, WNV infection rate was significantly higher in Wolbachia-infected mosquitoes compared to controls. Quantitative PCR of selected innate immune genes indicated that REL1 (the activator of the antiviral Toll immune pathway was down regulated in Wolbachia-infected relative to control mosquitoes. This is the first observation of Wolbachia-induced enhancement of a human pathogen in mosquitoes, suggesting that caution should be applied before releasing Wolbachia-infected insects as part of a vector-borne disease control program.

Modelling the potential spatial distribution of mosquito species using three different techniques

NARCIS (Netherlands)

Cianci, D.; Hartemink, N.; Ibáñez-Justicia, A.

2015-01-01

Background: Models for the spatial distribution of vector species are important tools in the assessment of the risk of establishment and subsequent spread of vector-borne diseases. The aims of this study are to define the environmental conditions suitable for several mosquito species through species

Declining malaria, rising of dengue and Zika virus: insights for mosquito vector control.

Science.gov (United States)

Benelli, Giovanni; Mehlhorn, Heinz

2016-05-01

The fight against mosquito-borne diseases is a challenge of huge public health importance. To our mind, 2015 was an extraordinary year for malaria control, due to three hot news: the Nobel Prize to Youyou Tu for the discovery of artemisinin, the development of the first vaccine against Plasmodium falciparum malaria [i.e. RTS,S/AS01 (RTS,S)], and the fall of malaria infection rates worldwide, with special reference to sub-Saharan Africa. However, there are major challenges that still deserve attention, in order to boost malaria prevention and control. Indeed, parasite strains resistant to artemisinin have been detected, and RTS,S vaccine does not offer protection against Plasmodium vivax malaria, which predominates in many countries outside of Africa. Furthermore, the recent outbreaks of Zika virus infections, occurring in South America, Central America and the Caribbean, represent the most recent of four arrivals of important arboviruses in the Western Hemisphere, over the last 20 years. Zika virus follows dengue (which slyly arrived in the hemisphere over decades and became more aggressive in the 1990s), West Nile virus (emerged in 1999) and chikungunya (emerged in 2013). Notably, there are no specific treatments for these arboviruses. The emerging scenario highlights that the effective and eco-friendly control of mosquito vectors, with special reference to highly invasive species such as Aedes aegypti and Aedes albopictus, is crucial. The concrete potential of screening plant species as sources of metabolites for parasitological purposes is worthy of attention, as elucidated by the Y. Tu's example. Notably, plant-borne molecules are often effective at few parts per million against Aedes, Ochlerotatus, Anopheles and Culex young instars, can be used for the rapid synthesis of mosquitocidal nanoformulations and even employed to prepare cheap repellents with low human toxicity. In addition, behaviour-based control tools relying to the employ of sound traps and the

Emerging Vector-Borne Diseases - Incidence through Vectors.

Science.gov (United States)

Savić, Sara; Vidić, Branka; Grgić, Zivoslav; Potkonjak, Aleksandar; Spasojevic, Ljubica

2014-01-01

Vector-borne diseases use to be a major public health concern only in tropical and subtropical areas, but today they are an emerging threat for the continental and developed countries also. Nowadays, in intercontinental countries, there is a struggle with emerging diseases, which have found their way to appear through vectors. Vector-borne zoonotic diseases occur when vectors, animal hosts, climate conditions, pathogens, and susceptible human population exist at the same time, at the same place. Global climate change is predicted to lead to an increase in vector-borne infectious diseases and disease outbreaks. It could affect the range and population of pathogens, host and vectors, transmission season, etc. Reliable surveillance for diseases that are most likely to emerge is required. Canine vector-borne diseases represent a complex group of diseases including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, ehrlichiosis, and leishmaniosis. Some of these diseases cause serious clinical symptoms in dogs and some of them have a zoonotic potential with an effect to public health. It is expected from veterinarians in coordination with medical doctors to play a fundamental role at primarily prevention and then treatment of vector-borne diseases in dogs. The One Health concept has to be integrated into the struggle against emerging diseases. During a 4-year period, from 2009 to 2013, a total number of 551 dog samples were analyzed for vector-borne diseases (borreliosis, babesiosis, ehrlichiosis, anaplasmosis, dirofilariosis, and leishmaniasis) in routine laboratory work. The analysis was done by serological tests - ELISA for borreliosis, dirofilariosis, and leishmaniasis, modified Knott test for dirofilariosis, and blood smear for babesiosis, ehrlichiosis, and anaplasmosis. This number of samples represented 75% of total number of samples that were sent for analysis for different diseases in dogs. Annually, on average more then half of the samples

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

Science.gov (United States)

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.

Canine and feline vector-borne diseases in Italy: current situation and perspectives

Directory of Open Access Journals (Sweden)

Dantas-Torres Filipe

2010-01-01

Full Text Available Abstract In Italy, dogs and cats are at risk of becoming infected by different vector-borne pathogens, including protozoa, bacteria, and helminths. Ticks, fleas, phlebotomine sand flies, and mosquitoes are recognized vectors of pathogens affecting cats and dogs, some of which (e.g., Anaplasma phagocytophilum, Borrelia burgdorferi, Dipylidium caninum, Leishmania infantum, Dirofilaria immitis, and Dirofilaria repens are of zoonotic concern. Recent studies have highlighted the potential of fleas as vectors of pathogens of zoonotic relevance (e.g., Rickettsia felis in this country. While some arthropod vectors (e.g., ticks and fleas are present in certain Italian regions throughout the year, others (e.g., phlebotomine sand flies are most active during the summer season. Accordingly, control strategies, such as those relying on the systematic use of acaricides and insecticides, should be planned on the basis of the ecology of both vectors and pathogens in different geographical areas in order to improve their effectiveness in reducing the risk of infection by vector-borne pathogens. This article reviews the current situation and perspectives of canine and feline vector-borne diseases in Italy.

Blood-feeding patterns of native mosquitoes and insights into their potential role as pathogen vectors in the Thames estuary region of the United Kingdom.

Science.gov (United States)

Brugman, V A; Hernández-Triana, L M; England, M E; Medlock, J M; Mertens, P P C; Logan, J G; Wilson, A J; Fooks, A R; Johnson, N; Carpenter, S

2017-03-27

The range of vertebrate hosts on which species of mosquito blood-feed is an important parameter for identifying potential vectors and in assessing the risk of incursion and establishment of vector-borne pathogens. In the United Kingdom, studies of mosquito host range have collected relatively few specimens and used techniques that could only broadly identify host species. This study conducted intensive collection and analysis of mosquitoes from a grazing marsh environment in southeast England. This site provides extensive wetland habitat for resident and migratory birds and has abundant human nuisance biting mosquitoes. The aim was to identify the blood-feeding patterns of mosquito species present at the site which could contribute to the transmission of pathogens. Twice-weekly collections of mosquitoes were made from Elmley Nature Reserve, Kent, between June and October 2014. Mosquitoes were collected using resting boxes, by aspiration from man-made structures and using a Mosquito Magnet Pro baited with 1-octen-3-ol. Blood-fed specimens were classified according to the degree of blood meal digestion using the Sella scale and vertebrate origin determined using sequencing of a fragment of the mitochondrial cytochrome C oxidase subunit I gene. Mosquitoes that were morphologically cryptic were identified to species level using multiplex PCR and sequencing methods. A total of 20,666 mosquitoes of 11 species were collected, and 2,159 (10.4%) were blood-fed (Sella scale II-VI); of these 1,341 blood-fed specimens were selected for blood meal analysis. Vertebrate origin was successfully identified in 964 specimens (72%). Collections of blood-fed individuals were dominated by Anopheles maculipennis complex (73.5%), Culiseta annulata (21.2%) and Culex pipiens form pipiens (10.4%). Nineteen vertebrate hosts comprising five mammals and 14 birds were identified as hosts for mosquitoes, including two migratory bird species. Feeding on birds by Culex modestus and Anopheles

Chemical composition, toxicity and non-target effects of Pinus kesiya essential oil: An eco-friendly and novel larvicide against malaria, dengue and lymphatic filariasis mosquito vectors.

Science.gov (United States)

Govindarajan, Marimuthu; Rajeswary, Mohan; Benelli, Giovanni

2016-07-01

Mosquitoes (Diptera: Culicidae) are vectors of important parasites and pathogens causing death, poverty and social disability worldwide, with special reference to tropical and subtropical countries. The overuse of synthetic insecticides to control mosquito vectors lead to resistance, adverse environmental effects and high operational costs. Therefore, the development of eco-friendly control tools is an important public health challenge. In this study, the mosquito larvicidal activity of Pinus kesiya leaf essential oil (EO) was evaluated against the malaria vector Anopheles stephensi, the dengue vector Aedes aegypti and the lymphatic filariasis vector Culex quinquefasciatus. The chemical composition of the EO was analyzed by gas chromatography-mass spectroscopy. GC-MS revealed that the P. kesiya EO contained 18 compounds. Major constituents were α-pinene, β-pinene, myrcene and germacrene D. In acute toxicity assays, the EO showed significant toxicity against early third-stage larvae of An. stephensi, Ae. aegypti and Cx. quinquefasciatus, with LC50 values of 52, 57, and 62µg/ml, respectively. Notably, the EO was safer towards several aquatic non-target organisms Anisops bouvieri, Diplonychus indicus and Gambusia affinis, with LC50 values ranging from 4135 to 8390µg/ml. Overall, this research adds basic knowledge to develop newer and safer natural larvicides from Pinaceae plants against malaria, dengue and filariasis mosquito vectors. Copyright © 2016 Elsevier Inc. All rights reserved.

Tadpoles of three common anuran species from Thailand do not prey on mosquito larvae.

Science.gov (United States)

Weterings, Robbie

2015-12-01

Tadpoles are often considered to be predators of mosquito larvae and are therefore beneficial for the control of certain disease vectors. Nevertheless, only a few species have actually been recorded to prey on mosquito larvae. The mosquito larvae predation rates of tadpoles of three common Thai anuran species (Bufo melanostictus, Kaloula pulchra and Hylarana raniceps) were experimentally tested. Tadpoles in varying developmental stages were used to assess a size/age effect on the predation rate. In addition, different instars of Culex quinquefasciatus were used in order to assess a prey size effect on the predation rates. All three species failed to show any evidence of mosquito larvae predation. Neither small nor large tadpoles fed on mosquito larvae. Prey size also did not affect predation. Although tadpoles do not feed on mosquito larvae, there may be other direct or indirect inter-specific interactions that adversely impact the development of larvae in shared habitats with tadpoles. © 2015 The Society for Vector Ecology.

Evaluation of larvicidal activity of medicinal plant extracts against three mosquito vectors.

Science.gov (United States)

Bagavan, A; Rahuman, A Abdul

2011-01-01

To evaluate the mosquito larvicidal activity of plant extracts. The hexane, chloroform, ethyl acetate, acetone, and methanol leaf, flower and seed extracts of Abrus precatorius (A. precatorius), Croton bonplandianum (C. bonplandianum), Cynodon dactylon (C. dactylon), Musa paradisiaca (M. paradisiaca) and Syzygium aromaticum (S. aromaticum) were tested against fourth instar larvae of Anopheles vagus (An. vagus), Armigeres subalbatus (Ar. subalbatus) and Culex vishnui (Cx. vishnui). The highest larval mortality was found in seed ethyl acetate extracts of A. precatorius and leaf extracts of C. bonplandianum, flower chloroform and methanol extracts of M. paradisiaca, and flower bud hexane extract of S. aromaticum against An. vagus with LC(50) values of 19.31, 39.96, 35.18, 79.90 and 85.90 μg/mL; leaf ethyl acetate and methanol extracts of C. dactylon, flower methanol extract of M. paradisiaca, flower bud methanol extract of S. aromaticum against Ar. subalbatus with LC(50) values of 21.67, 32.62, 48.90 and 78.28 μg/mL, and seed methanol of A. precatorius, flower methanol extract of M. paradisiaca, flower bud hexane extract of S. aromaticum against Cx. vishnui with LC(50) values of 136.84, 103.36 and 149.56 μg/mL, respectively. These results suggest that the effective plant crude extracts have the potential to be used as an ideal ecofriendly approach for the control of disease vectors. This study provides the first report on the larvicidal activity of crude solvent extracts of different mosquitoes. Copyright © 2011 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Ultra-low-volume space sprays in mosquito control: a critical review.

Science.gov (United States)

Bonds, J A S

2012-06-01

The availability of tools to control mosquito (Diptera:Culicidae) vectors that transmit disease is often limited by a variety of economic, environmental and social issues. In emergency conditions (epidemics, hurricanes, floods etc.), the application of pesticides as space sprays (either by ground or air) is the common method of choice in order to rapidly limit adult local mosquito production in the affected area. Space spray application now employs ultra-low-volume technology for the control of adult mosquitoes. However, the use of space sprays often raises social and environmental concerns by the general public that is served. This review will define and illustrate modern ultra-low-volume technology for the purpose of application as a space spray, as well as describing the engineering controls that have been developed to minimize the environmental impact. The primary social concern is validity and efficacy of application. To address this point, the review will attempt to synthesize the global literature to address the effectiveness of space sprays to significantly impact mosquito vectors in relation to human disease. © 2012 The Author. Medical and Veterinary Entomology © 2012 The Royal Entomological Society.

Vectors and transmission dynamics for Setaria tundra (Filarioidea; Onchocercidae, a parasite of reindeer in Finland

Directory of Open Access Journals (Sweden)

Kuusela Jussi

2009-01-01

Full Text Available Abstract Background Recent studies have revealed expansion by an array of Filarioid nematodes' into the northern boreal region of Finland. The vector-borne nematode, Setaria tundra, caused a serious disease outbreak in the Finnish reindeer population in 2003–05. The main aim of this study was to understand the outbreak dynamics and the rapid expansion of S. tundra in the sub arctic. We describe the vectors of S. tundra, and its development in vectors, for the first time. Finally we discuss the results in the context of the host-parasite ecology of S. tundra in Finland Results Development of S. tundra to the infective stage occurs in mosquitoes, (genera Aedes and Anopheles. We consider Aedes spp. the most important vectors. The prevalence of S. tundra naturally infected mosquitoes from Finland varied from 0.5 to 2.5%. The rate of development in mosquitoes was temperature-dependent. Infective larvae were present approximately 14 days after a blood meal in mosquitoes maintained at room temperature (mean 21 C, but did not develop in mosquitoes maintained outside for 22 days at a mean temperature of 14.1 C. The third-stage (infective larvae were elongated (mean length 1411 μm (SD 207, and width 28 μm (SD 2. The anterior end was blunt, and bore two liplike structures, the posterior end slight tapering with a prominent terminal papilla. Infective larvae were distributed anteriorly in the insect's body, the highest abundance being 70 larvae in one mosquito. A questionnaire survey revealed that the peak activity of Culicidae in the reindeer herding areas of Finland was from the middle of June to the end of July and that warm summer weather was associated with reindeer flocking behaviour on mosquito-rich wetlands. Conclusion In the present work, S. tundra vectors and larval development were identified and described for the first time. Aedes spp. mosquitoes likely serve as the most important and competent vectors for S. tundra in Finland. Warm summers

Identification of host blood from engorged mosquitoes collected in western Uganda using cytochrome oxidase I gene sequences.

Science.gov (United States)

Crabtree, Mary B; Kading, Rebekah C; Mutebi, John-Paul; Lutwama, Julius J; Miller, Barry R

2013-07-01

Emerging infectious disease events are frequently caused by arthropod-borne viruses (arboviruses) that are maintained in a zoonotic cycle between arthropod vectors and vertebrate wildlife species, with spillover to humans in areas where human and wildlife populations interface. The greater Congo basin region, including Uganda, has historically been a hot spot for emergence of known and novel arboviruses. Surveillance of arthropod vectors is a critical activity in monitoring and predicting outbreaks of arboviral disease, and identification of blood meals in engorged arthropods collected during surveillance efforts provides insight into the ecology of arboviruses and their vectors. As part of an ongoing arbovirus surveillance project we analyzed blood meals from engorged mosquitoes collected at five sites in western Uganda November 2008-June 2010. We extracted DNA from the dissected and triturated abdomens of engorged mosquito specimens. Mitochondrial cytochrome c oxidase I gene sequence was amplified by PCR and sequenced to identify the source of the mosquito host blood. Blood meals were analyzed from 533 engorged mosquito specimens; 440 of these blood meals were successfully identified from 33 mosquito species. Species identifications were made for 285 of the 440 identified specimens with the remainder identified to genus, family, or order. When combined with published arbovirus isolation and serologic survey data, our results suggest possible vector-reservoir relationships for several arboviruses, including Rift Valley fever virus and West Nile virus.

Meta-analyses of the proportion of Japanese encephalitis virus infection in vectors and vertebrate hosts.

Science.gov (United States)

Oliveira, Ana R S; Cohnstaedt, Lee W; Strathe, Erin; Hernández, Luciana Etcheverry; McVey, D Scott; Piaggio, José; Cernicchiaro, Natalia

2017-09-07

Japanese encephalitis (JE) is a zoonosis in Southeast Asia vectored by mosquitoes infected with the Japanese encephalitis virus (JEV). Japanese encephalitis is considered an emerging exotic infectious disease with potential for introduction in currently JEV-free countries. Pigs and ardeid birds are reservoir hosts and play a major role on the transmission dynamics of the disease. The objective of the study was to quantitatively summarize the proportion of JEV infection in vectors and vertebrate hosts from data pertaining to observational studies obtained in a systematic review of the literature on vector and host competence for JEV, using meta-analyses. Data gathered in this study pertained to three outcomes: proportion of JEV infection in vectors, proportion of JEV infection in vertebrate hosts, and minimum infection rate (MIR) in vectors. Random-effects subgroup meta-analysis models were fitted by species (mosquito or vertebrate host species) to estimate pooled summary measures, as well as to compute the variance between studies. Meta-regression models were fitted to assess the association between different predictors and the outcomes of interest and to identify sources of heterogeneity among studies. Predictors included in all models were mosquito/vertebrate host species, diagnostic methods, mosquito capture methods, season, country/region, age category, and number of mosquitos per pool. Mosquito species, diagnostic method, country, and capture method represented important sources of heterogeneity associated with the proportion of JEV infection; host species and region were considered sources of heterogeneity associated with the proportion of JEV infection in hosts; and diagnostic and mosquito capture methods were deemed important contributors of heterogeneity for the MIR outcome. Our findings provide reference pooled summary estimates of vector competence for JEV for some mosquito species, as well as of sources of variability for these outcomes. Moreover, this

MosqTent: An individual portable protective double-chamber mosquito trap for anthropophilic mosquitoes.

Directory of Open Access Journals (Sweden)

José Bento Pereira Lima

2017-03-01

Full Text Available Here, we describe the development of the MosqTent, an innovative double-chamber mosquito trap in which a human being attracts mosquitoes while is protected from being bitten within the inner chamber of the trap, while mosquitoes are lured to enter an outer chamber where they are trapped. The MosqTent previously collected an average of 3,000 anophelines/man-hour compared to 240 anophelines/man-hour for the human landing catch (HLC, thereby providing high numbers of human host-seeking mosquitoes while protecting the collector from mosquito bites. The MosqTent performed well by collecting a high number of specimens of Anopheles marajoara, a local vector and anthropophilic mosquito species present in high density, but not so well in collecting An. darlingi, an anthropophilic mosquito species considered the main vector in Brazil but is present in low-density conditions in the area. The HLC showed a higher efficiency in collecting An. darlingi in these low-density conditions. The MosqTent is light (<1 kg, portable (comes as a bag with two handles, flexible (can be used with other attractants, adaptable (can be deployed in a variety of environmental settings and weather conditions, and it can be used in the intra-, peri-, and in the extradomicile. Also, the MosqTent collected similar portions of parous females and anthropophilic mosquito species and collects specimens suitable for downstream analysis. Further developments may include testing for other fabric colors, different mesh sizes and dimensions for other hematophagous insects and conditions, additional chemical mosquito attractants, and even the replacement of the human attractant in favor of other attractants. MosqTent modifications that would allow the trap to be applied as a vector control tool with killing action could also be explored.

The entomopathogenic fungus Beauveria bassiana reduces instantaneous blood feeding in wild multi-insecticide-resistant Culex quinquefasciatus mosquitoes in Benin, West Africa

NARCIS (Netherlands)

Howard, A.F.V.; N'Guessan, R.; Koenraadt, C.J.M.; Asidi, A.; Farenhorst, M.; Akogbéto, M.; Thomas, M.B.; Knols, B.G.J.; Takken, W.

2010-01-01

Background Mosquito-borne diseases are still a major health risk in many developing countries, and the emergence of multi-insecticide-resistant mosquitoes is threatening the future of vector control. Therefore, new tools that can manage resistant mosquitoes are required. Laboratory studies show that

The entomopathogenic fungus Beauveria bassiana reduces instantaneous blood feeding in wild multi-insecticide-resistant Culex quinquefasciatus mosquitoes in Benin, West Africa

NARCIS (Netherlands)

Howard, A.F.V.; N'Guessan, R.; Koenraadt, C.J.M.; Asidi, A.; Farenhorst, M.; Akogbeto, M.; Thomas, M.B.; Knols, B.G.J.; Takken, W.

2010-01-01

Background: Mosquito-borne diseases are still a major health risk in many developing countries, and the emergence of multi-insecticide-resistant mosquitoes is threatening the future of vector control. Therefore, new tools that can manage resistant mosquitoes are required. Laboratory studies show

The entomopathogenic fungus Beauveria bassiana reduces instantaneous blood feeding in wild multi-insecticide-resistant Culex quinquefasciatus mosquitoes in Benin, West Africa

NARCIS (Netherlands)

Howard, Annabel Fv; N'Guessan, Raphael; Koenraadt, Constantianus Jm; Asidi, Alex; Farenhorst, Marit; Akogbéto, Martin; Thomas, Matthew B.; Knols, Bart Gj; Takken, Willem

2010-01-01

Mosquito-borne diseases are still a major health risk in many developing countries, and the emergence of multi-insecticide-resistant mosquitoes is threatening the future of vector control. Therefore, new tools that can manage resistant mosquitoes are required. Laboratory studies show that

Maternal Germline-Specific Genes in the Asian Malaria Mosquito Anopheles stephensi: Characterization and Application for Disease Control

Science.gov (United States)

Biedler, James K.; Qi, Yumin; Pledger, David; Macias, Vanessa M.; James, Anthony A.; Tu, Zhijian

2014-01-01

Anopheles stephensi is a principal vector of urban malaria on the Indian subcontinent and an emerging model for molecular and genetic studies of mosquito biology. To enhance our understanding of female mosquito reproduction, and to develop new tools for basic research and for genetic strategies to control mosquito-borne infectious diseases, we identified 79 genes that displayed previtellogenic germline-specific expression based on RNA-Seq data generated from 11 life stage–specific and sex-specific samples. Analysis of this gene set provided insights into the biology and evolution of female reproduction. Promoters from two of these candidates, vitellogenin receptor and nanos, were used in independent transgenic cassettes for the expression of artificial microRNAs against suspected mosquito maternal-effect genes, discontinuous actin hexagon and myd88. We show these promoters have early germline-specific expression and demonstrate 73% and 42% knockdown of myd88 and discontinuous actin hexagon mRNA in ovaries 48 hr after blood meal, respectively. Additionally, we demonstrate maternal-specific delivery of mRNA and protein to progeny embryos. We discuss the application of this system of maternal delivery of mRNA/miRNA/protein in research on mosquito reproduction and embryonic development, and for the development of a gene drive system based on maternal-effect dominant embryonic arrest. PMID:25480960

Transgenic Mosquitoes - Fact or Fiction?

Science.gov (United States)

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.

Optimization of formulation and delivery technology of entomopathogenic fungi for malaria vector control

NARCIS (Netherlands)

Mnyone, L.L.

2010-01-01

Vector control is one of the most effective means of controlling mosquito-borne diseases such as malaria. The broad goal of this strategy is to protect individuals against infective mosquito bites and, at the community level, to reduce the intensity of disease transmission. With the deployment of

Arthropod Innate Immune Systems and Vector-Borne Diseases.

Science.gov (United States)

Baxter, Richard H G; Contet, Alicia; Krueger, Kathryn

2017-02-21

Arthropods, especially ticks and mosquitoes, are the vectors for a number of parasitic and viral human diseases, including malaria, sleeping sickness, Dengue, and Zika, yet arthropods show tremendous individual variation in their capacity to transmit disease. A key factor in this capacity is the group of genetically encoded immune factors that counteract infection by the pathogen. Arthropod-specific pattern recognition receptors and protease cascades detect and respond to infection. Proteins such as antimicrobial peptides, thioester-containing proteins, and transglutaminases effect responses such as lysis, phagocytosis, melanization, and agglutination. Effector responses are initiated by damage signals such as reactive oxygen species signaling from epithelial cells and recognized by cell surface receptors on hemocytes. Antiviral immunity is primarily mediated by siRNA pathways but coupled with interferon-like signaling, antimicrobial peptides, and thioester-containing proteins. Molecular mechanisms of immunity are closely linked to related traits of longevity and fertility, and arthropods have the capacity for innate immunological memory. Advances in understanding vector immunity can be leveraged to develop novel control strategies for reducing the rate of transmission of both ancient and emerging threats to global health.

A review of mosquitoes associated with Rift Valley fever virus in Madagascar.

Science.gov (United States)

Tantely, Luciano M; Boyer, Sébastien; Fontenille, Didier

2015-04-01

Rift Valley fever (RVF) is a viral zoonotic disease occurring throughout Africa, the Arabian Peninsula, and Madagascar. The disease is caused by a Phlebovirus (RVF virus [RVFV]) transmitted to vertebrate hosts through the bite of infected mosquitoes. In Madagascar, the first RVFV circulation was reported in 1979 based on detection in mosquitoes but without epidemic episode. Subsequently, two outbreaks occurred: the first along the east coast and in the central highlands in 1990 and 1991 and the most recent along the northern and eastern coasts and in the central highlands in 2008 and 2009. Despite the presence of 24 mosquitoes species potentially associated with RVFV transmission in Madagascar, little associated entomological information is available. In this review, we list the RVFV vector, Culex antennatus, as well as other taxa as candidate vector species. We discuss risk factors from an entomological perspective for the re-emergence of RVF in Madagascar. © The American Society of Tropical Medicine and Hygiene.

Environmental and social-demographic predictors of the southern house mosquito Culex quinquefasciatus in New Orleans, Louisiana

Science.gov (United States)

Flooding events have become common throughout the world yet our understanding of how these events affect the spatial and temporal distribution of disease vectors such as mosquitoes is limited. This knowledge can guide development of effective and timely strategies for mitigating mosquito-borne disea...

Evaluation of organophosphorus and synthetic pyrethroid insecticides against six vector mosquitoe species Avaliação de inseticidas organofosforados e piretroides sintéticos contra seis mosquitos vetores

Directory of Open Access Journals (Sweden)

Domingo Montada Dorta

1993-12-01

Full Text Available Three organophosphorus compounds- malathion, folithion and temephos- and two synthetic pyrethroids- alphamethrin and deltamethrin- were used for monitoring the susceptibility status of larvae and adults of six vector mosquitoe species: Culex quinquefasciatus (Filariasis and Aedes albopictus (Dengue (both laboratory and field strains; laboratory strains of Aedes aegypti (Dengue, Anopheles slephensi and Anopheles culicifacies (Malaria, and Culex tritaeniorhynchus (Japanese encephalitis in India. From the LC50 values obtained for these insecticides, it was found that all mosquito species including the field strains of Cx. quinquefasciatus and Ae. albopictus were highly susceptible Except for Cx. quinquefasciatus (field strain against malathion, 100% mortality was observed at the discriminating dosages recommended by World Health Organization. The residual effect of alphamethrin, deltamethrin, malathion and folithion at 25 mg (ai/m² on different surfaces against six species of vector mosquitoes showed that alphamethrin was the most effective on all four treated surfaces (mud, plywood, cement and thatch. Nevertheless, residual efficacy lasted longer on thatch than on the other surfaces. Therefore, synthetic pyrethroids such as alphamethrin can be effectively employed in integrated vector control operations.Três compostos organo-fosforados - malation, folition e temefos -e dois piretroides sintéticos - alfametrina e deltametrina - foram usados para controlar o estado da susceptibilidade das larvas e adultos de seis mosquitos vetores na Índia. Foram utilizadas cepas de laboratório e área de Culex quinquefasciatus (filariasis e Aedes albopictus (Dengue e cepas de laboratório de Aedes aegypti (Dengue, Anopheles stephensi e Anopheles culicifacies (Malária e Culex tritaenorhynchus (encefalite japonesa. Os valores de C1(50 obtidos para esses inseticidas mostram que todas as espécies incluindo as cepas de área foram muito susceptíveis. Nos

High proportion of mosquito vectors in Zika forest, Uganda, feeding ...

African Journals Online (AJOL)

There is a steady increase in the contact between humans and wildlife, brought about by encroachment, destruction of natural forests, climatic and environmental changes. Mosquitoes get exposed to hosts and pathogens; creating possibilities for new disease patterns. Therefore, the identification of blood-meal sources is ...

Mosquito host choices on livestock amplifiers of Rift Valley fever virus in Kenya

Science.gov (United States)

Animal hosts may vary in their attraction and acceptability as components of the host location process for assessing biting rates of vectors and risk of exposure to pathogens. However, these parameters remain poorly understood for mosquito vectors of the Rift Valley fever (RVF), an arboviral disease...

The ecological foundations of transmission potential and vector-borne disease in urban landscapes.

Science.gov (United States)

LaDeau, Shannon L; Allan, Brian F; Leisnham, Paul T; Levy, Michael Z

2015-07-01

persistent gaps in understanding of vital rates and drivers in mosquito-vectored disease systems, and vast holes in understanding for other arthropod vectored diseases. Empirical studies are needed to better understand the physiological constraints and socio-ecological processes that generate heterogeneity in critical transmission parameters, including vector survival and fitness. Likewise, laboratory experiments and transmission models must evaluate vector response to realistic field conditions, including variability in sociological and environmental conditions.

Geostatistical evaluation of integrated marsh management impact on mosquito vectors using before-after-control-impact (BACI design

Directory of Open Access Journals (Sweden)

Dempsey Mary E

2009-06-01

Full Text Available Abstract Background In many parts of the world, salt marshes play a key ecological role as the interface between the marine and the terrestrial environments. Salt marshes are also exceedingly important for public health as larval habitat for mosquitoes that are vectors of disease and significant biting pests. Although grid ditching and pesticides have been effective in salt marsh mosquito control, marsh degradation and other environmental considerations compel a different approach. Targeted habitat modification and biological control methods known as Open Marsh Water Management (OMWM had been proposed as a viable alternative to marsh-wide physical alterations and chemical control. However, traditional larval sampling techniques may not adequately assess the impacts of marsh management on mosquito larvae. To assess the effectiveness of integrated OMWM and marsh restoration techniques for mosquito control, we analyzed the results of a 5-year OMWM/marsh restoration project to determine changes in mosquito larval production using GIS and geostatistical methods. Methods The following parameters were evaluated using "Before-After-Control-Impact" (BACI design: frequency and geographic extent of larval production, intensity of larval production, changes in larval habitat, and number of larvicide applications. The analyses were performed using Moran's I, Getis-Ord, and Spatial Scan statistics on aggregated before and after data as well as data collected over time. This allowed comparison of control and treatment areas to identify changes attributable to the OMWM/marsh restoration modifications. Results The frequency of finding mosquito larvae in the treatment areas was reduced by 70% resulting in a loss of spatial larval clusters compared to those found in the control areas. This effect was observed directly following OMWM treatment and remained significant throughout the study period. The greatly reduced frequency of finding larvae in the treatment

Geostatistical evaluation of integrated marsh management impact on mosquito vectors using before-after-control-impact (BACI) design.

Science.gov (United States)

Rochlin, Ilia; Iwanejko, Tom; Dempsey, Mary E; Ninivaggi, Dominick V

2009-06-23

In many parts of the world, salt marshes play a key ecological role as the interface between the marine and the terrestrial environments. Salt marshes are also exceedingly important for public health as larval habitat for mosquitoes that are vectors of disease and significant biting pests. Although grid ditching and pesticides have been effective in salt marsh mosquito control, marsh degradation and other environmental considerations compel a different approach. Targeted habitat modification and biological control methods known as Open Marsh Water Management (OMWM) had been proposed as a viable alternative to marsh-wide physical alterations and chemical control. However, traditional larval sampling techniques may not adequately assess the impacts of marsh management on mosquito larvae. To assess the effectiveness of integrated OMWM and marsh restoration techniques for mosquito control, we analyzed the results of a 5-year OMWM/marsh restoration project to determine changes in mosquito larval production using GIS and geostatistical methods. The following parameters were evaluated using "Before-After-Control-Impact" (BACI) design: frequency and geographic extent of larval production, intensity of larval production, changes in larval habitat, and number of larvicide applications. The analyses were performed using Moran's I, Getis-Ord, and Spatial Scan statistics on aggregated before and after data as well as data collected over time. This allowed comparison of control and treatment areas to identify changes attributable to the OMWM/marsh restoration modifications. The frequency of finding mosquito larvae in the treatment areas was reduced by 70% resulting in a loss of spatial larval clusters compared to those found in the control areas. This effect was observed directly following OMWM treatment and remained significant throughout the study period. The greatly reduced frequency of finding larvae in the treatment areas led to a significant decrease (approximately 44%) in

Understanding the Effects of Host Evolution and Skin Bacteria Composition on Disease Vector Choices

Science.gov (United States)

2016-04-14

Distribution Unlimited UU UU UU UU 14-04-2016 1-Sep-2014 31-Dec-2015 Final Report: Understanding the effects of host evolution and skin bacteria ...S) AND ADDRESS (ES) U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 mosquito, skin, bacteria , primate REPORT...reviewed journals: Final Report: Understanding the effects of host evolution and skin bacteria composition on disease vector choices Report Title Here

Exotic mosquito threats require strategic surveillance and response planning.

Science.gov (United States)

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.

VECTORS OF MALARIA AND FILARIASIS IN INDONESIA

Directory of Open Access Journals (Sweden)

Hoedojo Hoedojo

2012-09-01

Full Text Available Malaria at present is still one of the important mosquito-borne diseases in Indonesia. The disease is widespread all over the country and involves nearly all islands. Sixteen Anopheles species have been reconfirmed as malaria vectors. They were distributed geographi­cally as follows: Coastal areas and lagoons ------------------------------------- An sundaicus and An.subpictus Cultivated ricefields and swampy areas -------------------- An.aconitus, An.barbirostris, An.nigerrimus and An.sinensis Forest inland areas in shaded temporary pools, muddy animal wallows and hoof-prints -------------------------------------------------------- An.balabacensis, An.bancrofti, An.farauti, An.koliensis and An.punctulatus Swamp forest edge in ditches with vegeta- ---------------- An.letifer and An.ludlowae don Hilly areas in seepages, streams and clear moving water ---------------------------------------------- Anflavirostris, An.maculatus and Anminimus.   The species (of most general importance is An.sundaicus, which is restricted by its preference for brackish water and is prevalent in coastal areas of Java. Their types in behaviour of An.sundaicus appear as follows : 1. An.sundaicus in South Coast of Java in general. This species is essentially anthropophilic, exophagic and rests outdoor. It shows susceptible to DDT. 2. An.sundaicus in Cilacap, Central Java. This mosquito is a pure anthropophilic form. It bites man in houses and outdoors, rests indoors and is known resistant to DDT. 3. An.sundaicus in Yogyakarta and Purworejo, Central Java. This mosquito is a strong zoophilic species. It rests and prefers to bite outdoors and shows tolerance to DDT. Human filariasis in Indonesia is the result of infection by three endemic species, namely, Wuchereria bancrofti, Brugia malayi, and Brugia timori.W.bancrofti infection is found in both urban and rural areas. Twenty species of mosquitoes are confirmed as filariasis vectors. The urban type bancroftian filariasis

Surveillance of Mosquitoes and Selected Arthropod-Borne Viruses in the Context of Milan EXPO 2015

Directory of Open Access Journals (Sweden)

Mario Chiari

2016-07-01

Full Text Available From 1 May 2015 to 31 October 2015 over 20 million visitors from all over the world visited the Universal Exhibition (EXPO hosted by Milan (Lombardy region, Italy, raising concerns about the possible introduction of mosquito-borne diseases from endemic countries. The entomological surveillance protocol performed in Lombardy over the last three years was implemented in the EXPO area and in the two major regional airports using both Center for Disease Control CO2 and Biogents Sentinel traps. This surveillance aimed to estimate the presence and densities of putative vectors, and also to support investigations, including the vector species involved and area of diffusion, on the local spread of Chikungunya, Dengue and West Nile viruses (WNV by competent vectors. From 3544 mosquitoes belonging to five different species, 28 pools of Culex spp. and 45 pools of Aedes spp. were screened for the presence of WNV, and for both Chikungunya and flaviviruses, respectively. The entomological surveillance highlighted a low density of potential vectors in the surveyed areas and did not reveal the presence of Chikungunya or Dengue viruses in the local competent vectors inside the EXPO area or in the two airports. In addition, the surveillance reported a low density of Culex spp. mosquitoes, which all tested negative for WNV.

Integrated malaria vector control in different agro-ecosystems in western Kenya

NARCIS (Netherlands)

Imbahale, S.S.

2009-01-01

Malaria is a complex disease and its transmission is a function of the interaction between the Anopheles mosquito vector, the Plasmodium parasite, the hosts and the environment. Malaria control has mainly targeted the Plasmodium parasite or the adult anopheline mosquitoes. However, development of

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

Science.gov (United States)

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

A reappraisal of the role of mosquitoes in the transmission of myxomatosis in Britain.

Science.gov (United States)

Service, M W

1971-03-01

Field experiments were made in southern England to re-examine the possibility that mosquitoes in Britain might feed on wild rabbits and hence be vectors of myxomatosis. Mosquitoes of several species were attracted to rabbits enclosed in cylindrical traps and in a trap in which the animal was placed in a wire mesh cage. Substantial numbers of mosquitoes were also caught biting, or attempting to bite, tethered rabbits which were not in cages or traps. Evidence that mosquitoes fed on wild rabbits under natural conditions was obtained from results of precipitin tests made on blood-smears collected from mosquitoes caught resting amongst vegetation. On a few evenings mosquitoes were seen to be attracted to healthy wild rabbits and apparently attempting to feed on them. Batches of two mosquito species collected from the field were infected with myxoma virus.It was concluded that contrary to previous beliefs mosquitoes in Britain feed to a certain extent on wild rabbits, and therefore are potential vectors of myxomatosis. No attempts were made to assess their relative importance in the transmission of the disease, which in Britain is transmitted mainly by the rabbit flea.

Mosquito ovicidal properties of Ageratina adenophora (Family: Asteraceae) against filariasis vector, Culex quinquefasciatus (Diptera: Culicidae)

Science.gov (United States)

Mosquito-borne diseases with an economic impact create loss in commercial and labor outputs, particularly in countries with tropical and subtropical climates. Mosquito control is facing a threat because of the emergence of resistance to synthetic insecticides. Extracts from plants may be alternativ...

Alstonia boonei De Wild oil extract in the management of mosquito (Anopheles gambiae, a vector of malaria disease

Directory of Open Access Journals (Sweden)

Kayode David Ileke

2015-07-01

Full Text Available Objective: To evaluate the insecticidal potential of Alstonia boonei (A. boonei oils and derivatives against different life stages of a malaria vector, Anopheles gambiae. Methods: The leaf, stem bark and root bark of A. boonei were collected from an open field and air dried before being blended to fine powder. Oils from this plant were extracted by cold extraction and were prepared at different concentrations. Contact toxicity of A. boonei was tested against the larvae and pupae of the insect while smoke toxicity of the plant materials in form of mosquito coil was tested against the adult insect. Results: Alstodine recorded the highest insect mortality rate and the order of susceptibility of the life stages of the insect to the plant was pupae alstonine > stem bark extract > leaf extract > root bark extract.

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

Science.gov (United States)

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

A survey of mosquitoes breeding in used tires in Spain for the detection of imported potential vector species.

Science.gov (United States)

Roiz, D; Eritja, R; Escosa, R; Lucientes, J; Marquès, E; Melero-Alcíbar, R; Ruiz, S; Molina, R

2007-06-01

The used tire trade has facilitated the introduction, spread, and establishment of the Asian tiger mosquito, Aedes albopictus, and other mosquito species in several countries of America, Africa, Oceania, and Europe. A strategy for detecting these imported mosquito vectors was developed in Spain during 2003-2004 by EVITAR (multidisciplinary network for the study of viruses transmitted by arthropods and rodents). A survey in 45 locations found no invasive species. Eight autochthonous species of mosquitoes were detected in used tires, including Culex pipiens, Cx. hortensis, Cx. modestus, Anopheles atroparvus, An. claviger, Culiseta longiareolata, Cs. annulata, and Aedes caspius. Dominant species were Cx. pipiens and Cs. longiareolata. Aedes caspius was found in only once, near its natural breeding habitat. Considering the recent discovery of an established population of Ae. albopictus in Catalonia, the increasing commerce of used tires in Spain for recycling, storage, and recapping might greatly contribute to the rapid spread of this species across the Iberian Peninsula.

Transmission traits of malaria parasites within the mosquito: Genetic variation, phenotypic plasticity, and consequences for control.

Science.gov (United States)

Lefevre, Thierry; Ohm, Johanna; Dabiré, Kounbobr R; Cohuet, Anna; Choisy, Marc; Thomas, Matthew B; Cator, Lauren

2018-04-01

Evaluating the risk of emergence and transmission of vector-borne diseases requires knowledge of the genetic and environmental contributions to pathogen transmission traits. Compared to the significant effort devoted to understanding the biology of malaria transmission from vertebrate hosts to mosquito vectors, the strategies that malaria parasites have evolved to maximize transmission from vectors to vertebrate hosts have been largely overlooked. While determinants of infection success within the mosquito host have recently received attention, the causes of variability for other key transmission traits of malaria, namely the duration of parasite development and its virulence within the vector, as well as its ability to alter mosquito behavior, remain largely unknown. This important gap in our knowledge needs to be bridged in order to obtain an integrative view of the ecology and evolution of malaria transmission strategies. Associations between transmission traits also need to be characterized, as they trade-offs and constraints could have important implications for understanding the evolution of parasite transmission. Finally, theoretical studies are required to evaluate how genetic and environmental influences on parasite transmission traits can shape malaria dynamics and evolution in response to disease control.

Developing Exon-Primed Intron-Crossing (EPIC) markers for population genetic studies in three Aedes disease vectors.

Science.gov (United States)

White, Vanessa Linley; Endersby, Nancy Margaret; Chan, Janice; Hoffmann, Ary Anthony; Weeks, Andrew Raymond

2015-03-01

Aedes aegypti, Aedes notoscriptus, and Aedes albopictus are important vectors of many arboviruses implicated in human disease such as dengue fever. Genetic markers applied across vector species can provide important information on population structure, gene flow, insecticide resistance, and taxonomy, however, robust microsatellite markers have proven difficult to develop in these species and mosquitoes generally. Here we consider the utility and transferability of 15 Ribosome protein (Rp) Exon-Primed Intron-Crossing (EPIC) markers for population genetic studies in these 3 Aedes species. Rp EPIC markers designed for Ae. aegypti also successfully amplified populations of the sister species, Ae. albopictus, as well as the distantly related species, Ae. notoscriptus. High SNP and good indel diversity in sequenced alleles plus support for amplification of the same regions across populations and species were additional benefits of these markers. These findings point to the general value of EPIC markers in mosquito population studies. © 2014 Institute of Zoology, Chinese Academy of Sciences.

Emerging vector borne diseases – incidence through vectors

Directory of Open Access Journals (Sweden)

Sara eSavic

2014-12-01

Full Text Available Vector borne diseases use to be a major public health concern only in tropical and subtropical areas, but today they are an emerging threat for the continental and developed countries also. Nowdays, in intercontinetal countries, there is a struggle with emerging diseases which have found their way to appear through vectors. Vector borne zoonotic diseases occur when vectors, animal hosts, climate conditions, pathogens and susceptible human population exist at the same time, at the same place. Global climate change is predicted to lead to an increase in vector borne infectious diseases and disease outbreaks. It could affect the range and popultion of pathogens, host and vectors, transmission season, etc. Reliable surveilance for diseases that are most likely to emerge is required. Canine vector borne diseases represent a complex group of diseases including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, erlichiosis, leishmaniosis. Some of these diseases cause serious clinical symptoms in dogs and some of them have a zoonotic potential with an effect to public health. It is expected from veterinarians in coordination with medical doctors to play a fudamental role at primeraly prevention and then treatment of vector borne diseases in dogs. The One Health concept has to be integrated into the struggle against emerging diseases.During a four year period, from 2009-2013, a total number of 551 dog samples were analysed for vector borne diseases (borreliosis, babesiosis, erlichiosis, anaplasmosis, dirofilariosis and leishmaniasis in routine laboratory work. The analysis were done by serological tests – ELISA for borreliosis, dirofilariosis and leishmaniasis, modified Knott test for dirofilariosis and blood smear for babesiosis, erlichiosis and anaplasmosis. This number of samples represented 75% of total number of samples that were sent for analysis for different diseases in dogs. Annually, on avarege more then half of the samples

USDA Mosquito Control Product Research for the US Military

Science.gov (United States)

New techniques that were developed at the USDA to protect deployed military troops from the threat of vector-borne diseases and are also applicable for use by civilian mosquito control program use are described. Techniques to be illustrated include: (1) novel military personal protection methods, (2...

A revision of thirteen species of Triatominae (Hemiptera: Reduviidae vectors of Chagas disease in Mexico

Directory of Open Access Journals (Sweden)

Salazar-Schettino Paz Maria

2010-10-01

Full Text Available Vectors of Trypanosoma cruzi, parasite responsible for Chagas disease, are divided in intradomestic, peridomestic and sylvatic. The intradomestic are Triatoma barberi and Triatoma dimidiata, two species that represent the highest health risk among the Mexican population. Triatoma dimidiata is a species found mainly inside human habitats, but in Yucatan, it corresponds to the peridomicile vectors. Also in the peridomicile most of Chagas disease vectors are found: Meccus bassolsae, M. longipennis, M. mazzottii, M pallidipennis, M. phyllosomus, M picturata, Triatoma gerstaeckeri, T mexicana, T rubida, Dipetalogaster máxima (the last two are in the process of becoming adapted to the domicile, Panstrongylus rufotuberculatus which occasionally enters the domicile in its adult stage, and Rhodnius prolixus, which is practically controlled in the country. Peridomestic vectors are of lower risk in the transmission dynamics, as compared to the intradomestic ones. For the control of the intradomestic vectors, health education programs, improvements of housing, and the use of pesticides are essential To control the peridomestic vectors, health education programs are required, as well as the use of mosquito nets on doors and windows and around beds, aside from cementing the stone wall fences.

Identification of four evolutionarily related G protein-coupled receptors from the malaria mosquito Anopheles gambiae

DEFF Research Database (Denmark)

Belmont, Martin; Cazzamali, Giuseppe; Williamson, Michael

2006-01-01

The mosquito Anopheles gambiae is an important vector for malaria, which is one of the most serious human parasitic diseases in the world, causing up to 2.7 million deaths yearly. To contribute to our understanding of A. gambiae and to the transmission of malaria, we have now cloned four evolutio......The mosquito Anopheles gambiae is an important vector for malaria, which is one of the most serious human parasitic diseases in the world, causing up to 2.7 million deaths yearly. To contribute to our understanding of A. gambiae and to the transmission of malaria, we have now cloned four...... evolutionarily related G protein-coupled receptors (GPCRs) from this mosquito and expressed them in Chinese hamster ovary cells. After screening of a library of thirty-three insect or other invertebrate neuropeptides and eight biogenic amines, we could identify (de-orphanize) three of these GPCRs as...... relationship to the A. gambiae and other insect AKH receptors suggested that it is a receptor for an AKH-like peptide. This is the first published report on evolutionarily related AKH, corazonin, and CCAP receptors in mosquitoes....

Aedes albopictus mosquito: the main vector of the 2007 Chikungunya outbreak in Gabon.

Directory of Open Access Journals (Sweden)

Frédéric Pagès

Full Text Available The primary vector at the origin of the 2007 outbreak in Libreville, Gabon is identified as Aedes albopictus, trapped around the nearby French military camp. The Chikungunya virus was isolated from mosquitoes and found to be identical to the A226V circulating human strain. This is the first field study showing the role of the recently arrived species Aedes albopictus in Chikungunya virus transmission in Central Africa, and it demonstrates this species' role in modifying the epidemiological presentation of Chikungunya in Gabon.

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

Directory of Open Access Journals (Sweden)

Fernando Abad-Franch

2017-01-01

Full Text Available 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.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 that it was a before-after trial lacking

Insecticide Resistance in the Dengue Vector Aedes aegypti from Martinique: Distribution, Mechanisms and Relations with Environmental Factors

OpenAIRE

Marcombe , Sébastien; Blanc Mathieu , Romain; Pocquet , Nicolas; Riaz , Muhammad-Asam; Poupardin , Rodolphe; Sélior , Serge; Darriet , Frédéric; Reynaud , Stéphane; Yebakima , André; Corbel , Vincent; David , Jean-Philippe; Chandre , Fabrice

2012-01-01

International audience; Dengue is an important mosquito borne viral disease in Martinique Island (French West Indies). The viruses responsible for dengue are transmitted by Aedes aegypti, an indoor day-biting mosquito. The most effective proven method for disease prevention has been by vector control by various chemical or biological means. Unfortunately insecticide resistance has already been observed on the Island and recently showed to significantly reduce the efficacy of vector control in...

North American Wetlands and Mosquito Control

Science.gov (United States)

Rey, Jorge R.; Walton, William E.; Wolfe, Roger J.; Connelly, Roxanne; O’Connell, Sheila M.; Berg, Joe; Sakolsky-Hoopes, Gabrielle E.; Laderman, Aimlee D.

2012-01-01

Wetlands are valuable habitats that provide important social, economic, and ecological services such as flood control, water quality improvement, carbon sequestration, pollutant removal, and primary/secondary production export to terrestrial and aquatic food chains. There is disagreement about the need for mosquito control in wetlands and about the techniques utilized for mosquito abatement and their impacts upon wetlands ecosystems. Mosquito control in wetlands is a complex issue influenced by numerous factors, including many hard to quantify elements such as human perceptions, cultural predispositions, and political climate. In spite of considerable progress during the last decades, habitat protection and environmentally sound habitat management still remain inextricably tied to politics and economics. Furthermore, the connections are often complex, and occur at several levels, ranging from local businesses and politicians, to national governments and multinational institutions. Education is the key to lasting wetlands conservation. Integrated mosquito abatement strategies incorporate many approaches and practicable options, as described herein, and need to be well-defined, effective, and ecologically and economically sound for the wetland type and for the mosquito species of concern. The approach will certainly differ in response to disease outbreaks caused by mosquito-vectored pathogens versus quality of life issues caused by nuisance-biting mosquitoes. In this contribution, we provide an overview of the ecological setting and context for mosquito control in wetlands, present pertinent information on wetlands mosquitoes, review the mosquito abatement options available for current wetlands managers and mosquito control professionals, and outline some necessary considerations when devising mosquito control strategies. Although the emphasis is on North American wetlands, most of the material is applicable to wetlands everywhere. PMID:23222252

Modeling Occurrence of Urban Mosquitos Based on Land Use Types and Meteorological Factors in Korea

Directory of Open Access Journals (Sweden)

Yong-Su Kwon

2015-10-01

Full Text Available Mosquitoes are a public health concern because they are vectors of pathogen, which cause human-related diseases. It is well known that the occurrence of mosquitoes is highly influenced by meteorological conditions (e.g., temperature and precipitation and land use, but there are insufficient studies quantifying their impacts. Therefore, three analytical methods were applied to determine the relationships between urban mosquito occurrence, land use type, and meteorological factors: cluster analysis based on land use types; principal component analysis (PCA based on mosquito occurrence; and three prediction models, support vector machine (SVM, classification and regression tree (CART, and random forest (RF. We used mosquito data collected at 12 sites from 2011 to 2012. Mosquito abundance was highest from August to September in both years. The monitoring sites were differentiated into three clusters based on differences in land use type such as culture and sport areas, inland water, artificial grasslands, and traffic areas. These clusters were well reflected in PCA ordinations, indicating that mosquito occurrence was highly influenced by land use types. Lastly, the RF represented the highest predictive power for mosquito occurrence and temperature-related factors were the most influential. Our study will contribute to effective control and management of mosquito occurrences.

Can Horton hear the whos? The importance of scale in mosquito-borne disease.

Science.gov (United States)

Lord, C C; Alto, B W; Anderson, S L; Connelly, C R; Day, J F; Richards, S L; Smartt, C T; Tabachnick, W J

2014-03-01

The epidemiology of vector-borne pathogens is determined by mechanisms and interactions at different scales of biological organization, from individual-level cellular processes to community interactions between species and with the environment. Most research, however, focuses on one scale or level with little integration between scales or levels within scales. Understanding the interactions between levels and how they influence our perception of vector-borne pathogens is critical. Here two examples of biological scales (pathogen transmission and mosquito mortality) are presented to illustrate some of the issues of scale and to explore how processes on different levels may interact to influence mosquito-borne pathogen transmission cycles. Individual variation in survival, vector competence, and other traits affect population abundance, transmission potential, and community structure. Community structure affects interactions between individuals such as competition and predation, and thus influences the individual-level dynamics and transmission potential. Modeling is a valuable tool to assess interactions between scales and how processes at different levels can affect transmission dynamics. We expand an existing model to illustrate the types of studies needed, showing that individual-level variation in viral dose acquired or needed for infection can influence the number of infectious vectors. It is critical that interactions within and among biological scales and levels of biological organization are understood for greater understanding of pathogen transmission with the ultimate goal of improving control of vector-borne pathogens.

Implementing Cargo Movement into Climate Based Risk Assessment of Vector-Borne Diseases

Directory of Open Access Journals (Sweden)

Stephanie Margarete Thomas

2014-03-01

Full Text Available During the last decades the disease vector Aedes albopictus (Asian tiger mosquito has rapidly spread around the globe. Global shipment of goods contributes to its permanent introduction. Invaded regions are facing novel and serious public health concerns, especially regarding the transmission of formerly non-endemic arboviruses such as dengue and chikungunya. The further development and potential spread to other regions depends largely on their climatic suitability. Here, we have developed a tool for identifying and prioritizing European areas at risk for the establishment of Aedes albopictus by taking into account, for the first time, the freight imports from this mosquito’s endemic countries and the climate suitability at harbors and their surrounding regions. In a second step we consider the further transport of containers by train and inland waterways because these types of transport can be well controlled. We identify European regions at risk, where a huge amount of transported goods meet climatically suitable conditions for the disease vector. The current and future suitability of the climate for Aedes albopictus was modeled by a correlative niche model approach and the Regional Climate Model COSMO-CLM. This risk assessment combines impacts of globalization and global warming to improve effective and proactive interventions in disease vector surveillance and control actions.

Potential impact of climate change on emerging vector-borne and other infections in the UK.

Science.gov (United States)

Baylis, Matthew

2017-12-05

Climate is one of several causes of disease emergence. Although half or more of infectious diseases are affected by climate it appears to be a relatively infrequent cause of human disease emergence. Climate mostly affects diseases caused by pathogens that spend part of their lifecycle outside of the host, exposed to the environment. The most important routes of transmission of climate sensitive diseases are by arthropod (insect and tick) vectors, in water and in food. Given the sensitivity of many diseases to climate, it is very likely that at least some will respond to future climate change. In the case of vector-borne diseases this response will include spread to new areas. Several vector-borne diseases have emerged in Europe in recent years; these include vivax malaria, West Nile fever, dengue fever, Chikungunya fever, leishmaniasis, Lyme disease and tick-borne encephalitis. The vectors of these diseases are mosquitoes, sand flies and ticks. The UK has endemic mosquito species capable of transmitting malaria and probably other pathogens, and ticks that transmit Lyme disease. The UK is also threatened by invasive mosquito species known to be able to transmit West Nile, dengue, chikungunya and Zika, and sand flies that spread leishmaniasis. Warmer temperatures in the future will increase the suitability of the UK's climate for these invasive species, and increase the risk that they may spread disease. While much attention is on invasive species, it is important to recognize the threat presented by native species too. Proposed actions to reduce the future impact of emerging vector-borne diseases in the UK include insect control activity at points of entry of vehicles and certain goods, wider surveillance for mosquitoes and sand flies, research into the threat posed by native species, increased awareness of the medical profession of the threat posed by specific diseases, regular risk assessments, and increased preparedness for the occurrence of a disease emergency.

Peridomestic Aedes malayensis and Aedes albopictus are capable vectors of arboviruses in cities.

Science.gov (United States)

Mendenhall, Ian H; Manuel, Menchie; Moorthy, Mahesh; Lee, Theodore T M; Low, Dolyce H W; Missé, Dorothée; Gubler, Duane J; Ellis, Brett R; Ooi, Eng Eong; Pompon, Julien

2017-06-01

Dengue and chikungunya are global re-emerging mosquito-borne diseases. In Singapore, sustained vector control coupled with household improvements reduced domestic mosquito populations for the past 45 years, particularly the primary vector Aedes aegypti. However, while disease incidence was low for the first 30 years following vector control implementation, outbreaks have re-emerged in the past 15 years. Epidemiological observations point to the importance of peridomestic infection in areas not targeted by control programs. We investigated the role of vectors in peri-domestic areas. We carried out entomological surveys to identify the Aedes species present in vegetated sites in highly populated areas and determine whether mosquitoes were present in open-air areas frequented by people. We compared vector competence of Aedes albopictus and Aedes malayensis with Ae. aegypti after oral infection with sympatric dengue serotype 2 and chikungunya viruses. Mosquito saliva was tested for the presence of infectious virus particles as a surrogate for transmission following oral infection. We identified Aedes albopictus and Aedes malayensis throughout Singapore and quantified their presence in forested and opened grassy areas. Both Ae. albopictus and Ae. malayensis can occupy sylvatic niches and were highly susceptible to both arboviruses. A majority of saliva of infected Ae. malayensis contained infectious particles for both viruses. Our study reveals the prevalence of competent vectors in peri-domestic areas, including Ae. malayensis for which we established the vector status. Epidemics can be driven by infection foci, which are epidemiologically enhanced in the context of low herd immunity, selective pressure on arbovirus transmission and the presence of infectious asymptomatic persons, all these conditions being present in Singapore. Learning from Singapore's vector control success that reduced domestic vector populations, but has not sustainably reduced arboviral incidence

加强我国寨卡病毒病等蚊媒传染病的预防控制%Strengthen the prevention and control of Zika virus disease and other mosquito-borne infectious diseases in China

Institute of Scientific and Technical Information of China (English)

朱翠云; 卢洪洲

2016-01-01

寨卡病毒病是一种主要通过伊蚊叮咬传播的蚊媒传染病。伊蚊除了可以传播寨卡病毒外，还可以传播黄热病、登革热等多种疾病。近年来，随着旅行和贸易全球化、气候变暖等，蚊媒传染病相关疫情在全球多地暴发。该文主要介绍寨卡病毒病、黄热病等在我国首次输入的蚊媒传染病的流行情况，并对预防控制实施的重点措施进行了总结。%Zika virus disease is a mosquito-borne disease with aedes as a potential viral vector. Besides Zika virus, aedes can also serve as a vector for other viruses such as yellow fever virus and dengue virus.With the impact of globalization and climate changes, many regions in the world are experiencing outbreaks of mosquito-borne diseases in recently years.This paper focuses on the epidemic, prevention and control measures of mosquito-borne infectious diseases such as Zika virus disease and yellow fever which are firstly imported to China.

Chikungunya Virus Infection of Aedes Mosquitoes.

Science.gov (United States)

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.

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

International Nuclear Information System (INIS)

Bourtzis, K.; Lees, R.S.; Hendrichs, J.; Vreysen, M.J.B.

2016-01-01

Mosquitoes (Diptera: Culicidae) and tsetse flies (Diptera: Glossinidae) are bloodsucking vectors of human and animal pathogens. Mosquito-borne diseases (malaria, filariasis, dengue, chikungunya and Zika) 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 sexseparation 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. (author)

Multiple insecticide resistances in the disease vector Culex p. quinquefasciatus from Western Indian Ocean.

Science.gov (United States)

Pocquet, Nicolas; Milesi, Pascal; Makoundou, Patrick; Unal, Sandra; Zumbo, Betty; Atyame, Célestine; Darriet, Frédéric; Dehecq, Jean-Sébastien; Thiria, Julien; Bheecarry, Ambicadutt; Iyaloo, Diana P; Weill, Mylène; Chandre, Fabrice; Labbé, Pierrick

2013-01-01

Several mosquito-borne diseases affect the Western Indian Ocean islands. Culex pipiens quinquefasciatus is one of these vectors and transmits filariasis, Rift Valley and West Nile viruses and the Japanese encephalitis. To limit the impact of these diseases on public health, considerable vector control efforts have been implemented since the 50s, mainly through the use of neurotoxic insecticides belonging to Organochlorines (OC), Organophosphates (OP) and pyrethroids (PYR) families. However, mosquito control failures have been reported on site, and they were probably due to the selection of resistant individuals in response to insecticide exposure. In this study, we used different approaches to establish a first regional assessment of the levels and mechanisms of resistance to various insecticides. Bioassays were used to evaluate resistance to various insecticides, enzyme activity was measured to assess the presence of metabolic resistances through elevated detoxification, and molecular identification of known resistance alleles was investigated to determine the frequency of target-site mutations. These complementary approaches showed that resistance to the most used insecticides families (OC, OP and PYR) is widespread at a regional scale. However, the distribution of the different resistance genes is quite heterogeneous among the islands, some being found at high frequencies everywhere, others being frequent in some islands and absent in others. Moreover, two resistance alleles displayed clinal distributions in Mayotte and La Réunion, probably as a result of a heterogeneous selection due to local treatment practices. These widespread and diverse resistance mechanisms reduce the capacity of resistance management through classical strategies (e.g. insecticide rotation). In case of a disease outbreak, it could undermine the efforts of the vector control services, as only few compounds could be used. It thus becomes urgent to find alternatives to control populations

Multiple insecticide resistances in the disease vector Culex p. quinquefasciatus from Western Indian Ocean.

Directory of Open Access Journals (Sweden)

Nicolas Pocquet

Full Text Available Several mosquito-borne diseases affect the Western Indian Ocean islands. Culex pipiens quinquefasciatus is one of these vectors and transmits filariasis, Rift Valley and West Nile viruses and the Japanese encephalitis. To limit the impact of these diseases on public health, considerable vector control efforts have been implemented since the 50s, mainly through the use of neurotoxic insecticides belonging to Organochlorines (OC, Organophosphates (OP and pyrethroids (PYR families. However, mosquito control failures have been reported on site, and they were probably due to the selection of resistant individuals in response to insecticide exposure. In this study, we used different approaches to establish a first regional assessment of the levels and mechanisms of resistance to various insecticides. Bioassays were used to evaluate resistance to various insecticides, enzyme activity was measured to assess the presence of metabolic resistances through elevated detoxification, and molecular identification of known resistance alleles was investigated to determine the frequency of target-site mutations. These complementary approaches showed that resistance to the most used insecticides families (OC, OP and PYR is widespread at a regional scale. However, the distribution of the different resistance genes is quite heterogeneous among the islands, some being found at high frequencies everywhere, others being frequent in some islands and absent in others. Moreover, two resistance alleles displayed clinal distributions in Mayotte and La Réunion, probably as a result of a heterogeneous selection due to local treatment practices. These widespread and diverse resistance mechanisms reduce the capacity of resistance management through classical strategies (e.g. insecticide rotation. In case of a disease outbreak, it could undermine the efforts of the vector control services, as only few compounds could be used. It thus becomes urgent to find alternatives to

Paternal effect of the nuclear formin-like protein MISFIT on Plasmodium development in the mosquito vector.

Directory of Open Access Journals (Sweden)

Ellen S C Bushell

2009-08-01

Full Text Available Malaria parasites must undergo sexual and sporogonic development in mosquitoes before they can infect their vertebrate hosts. We report the discovery and characterization of MISFIT, the first protein with paternal effect on the development of the rodent malaria parasite Plasmodium berghei in Anopheles mosquitoes. MISFIT is expressed in male gametocytes and localizes to the nuclei of male gametocytes, zygotes and ookinetes. Gene disruption results in mutant ookinetes with reduced genome content, microneme defects and altered transcriptional profiles of putative cell cycle regulators, which yet successfully invade the mosquito midgut. However, developmental arrest ensues during the ookinete transformation to oocysts leading to malaria transmission blockade. Genetic crosses between misfit mutant parasites and parasites that are either male or female gamete deficient reveal a strict requirement for a male misfit allele. MISFIT belongs to the family of formin-like proteins, which are known regulators of the dynamic remodeling of actin and microtubule networks. Our data identify the ookinete-to-oocyst transition as a critical cell cycle checkpoint in Plasmodium development and lead us to hypothesize that MISFIT may be a regulator of cell cycle progression. This study offers a new perspective for understanding the male contribution to malaria parasite development in the mosquito vector.

Nesting bird "host funnel" increases mosquito-bird contact rate.

Science.gov (United States)

Caillouët, Kevin A; Riggan, Anna E; Bulluck, Lesley P; Carlson, John C; Sabo, Roy T

2013-03-01

Increases in vector-host contact rates can enhance arbovirus transmission intensity. We investigated weekly fluctuations in contact rates between mosquitoes and nesting birds using the recently described Nest Mosquito Trap (NMT). The number of mosquitoes per nestling increased from nesting season. Our evidence suggests the coincidence of the end of the avian nesting season and increasing mosquito abundances may have caused a "host funnel," concentrating host-seeking mosquitoes to the few remaining nestlings. The relative abundance of mosquitoes collected by the NMT suggests that significantly more Aedes albopictus (Skuse) and Culex pipiens (L.) /restuans (Theobald) sought nesting bird bloodmeals than were predicted by their relative abundances in CO2-baited Centers for Disease Control and Prevention light and gravid traps. Culex salinarius (Coquillett) and Culex erraticus Dyar and Knab were collected in NMTs in proportion to their relative abundances in the generic traps. Temporal host funnels and nesting bird host specificity may enhance arbovirus amplification and explain observed West Nile virus and St. Louis encephalitis virus amplification periods.

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

OpenAIRE

Cornet, St?phane; Gandon, Sylvain; Rivero, Ana

2013-01-01

Background Insecticide resistance has the potential to alter vector immune competence and consequently affect the transmission of diseases. Methods 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 d...

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

Science.gov (United States)

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

Anopheles plumbeus (Diptera: Culicidae) in Germany: updated geographic distribution and public health impact of a nuisance and vector mosquito.

Science.gov (United States)

Heym, Eva C; Kampen, Helge; Fahle, Marcus; Hohenbrink, Tobias L; Schäfer, Mandy; Scheuch, Dorothee E; Walther, Doreen

2017-01-01

The aim of this study was to map the current spatial distribution of Anopheles plumbeus in Germany, a potential vector of malaria parasites and West Nile virus. Reports of mass occurrence and nuisance connected with artificial breeding site usage by this species were analysed. Distribution data were collected from 2011 to 2014 mainly through trapping and submissions of adult mosquito specimens to a citizen science project. In the framework of the latter, additional information was gathered on recent nuisance incidents caused by An. plumbeus, including a longitudinal analysis of mosquito occurrence and the impact of management measures at a nuisance site in south-western Germany. Based on the most comprehensive set of collection data obtained during the last decades, An. plumbeus is shown to be widely distributed over Germany. The data also indicate a continuing extension of the breeding site repertoire of the species from natural to artificial habitats that facilitate mass development. Increasing incidents of persistent nuisance suggest that this mosquito species is rarely diagnosed correctly and managed adequately. As An. plumbeus is both a serious nuisance pest and a potential vector species, awareness of this species and the public health problems linked to it should be raised among pest managers and public health personnel. © 2016 John Wiley & Sons Ltd.

Detection and molecular characterization of the mosquito-borne filarial nematode Setaria tundra in Danish roe deer (Capreolus capreolus)

DEFF Research Database (Denmark)

Enemark, Heidi Larsen; Oksanen, Antti; Chriél, Mariann

2017-01-01

Setaria tundra is a mosquito-borne filarial nematode of cervids in Europe. It has recently been associated with an emerging epidemic disease causing severe morbidity and mortality in reindeer and moose in Finland. Here, we present the first report of S. tundra in six roe deer (Capreolus capreolus...... Europe. Roe deer are generally considered as asymptomatic carriers and their numbers in Denmark have increased significantly in recent decades. In light of climatic changes which result in warmer, more humid weather in Scandinavia greater numbers of mosquitoes and, especially, improved conditions...... for development of parasite larvae in the mosquito vectors are expected, which may lead to increasing prevalence of S. tundra. Monitoring of this vector-borne parasite may thus be needed in order to enhance the knowledge of factors promoting its expansion and prevalence as well as predicting disease outbreaks. (C...

Magnetic nanoparticles are highly toxic to chloroquine-resistant Plasmodium falciparum, dengue virus (DEN-2), and their mosquito vectors.

Science.gov (United States)

Murugan, Kadarkarai; Wei, Jiang; Alsalhi, Mohamad Saleh; Nicoletti, Marcello; Paulpandi, Manickam; Samidoss, Christina Mary; Dinesh, Devakumar; Chandramohan, Balamurugan; Paneerselvam, Chellasamy; Subramaniam, Jayapal; Vadivalagan, Chithravel; Wei, Hui; Amuthavalli, Pandiyan; Jaganathan, Anitha; Devanesan, Sandhanasamy; Higuchi, Akon; Kumar, Suresh; Aziz, Al Thabiani; Nataraj, Devaraj; Vaseeharan, Baskaralingam; Canale, Angelo; Benelli, Giovanni

2017-02-01

A main challenge in parasitology is the development of reliable tools to prevent or treat mosquito-borne diseases. We investigated the toxicity of magnetic nanoparticles (MNP) produced by Magnetospirillum gryphiswaldense (strain MSR-1) on chloroquine-resistant (CQ-r) and sensitive (CQ-s) Plasmodium falciparum, dengue virus (DEN-2), and two of their main vectors, Anopheles stephensi and Aedes aegypti, respectively. MNP were studied by Fourier-transform infrared spectroscopy and transmission electron microscopy. They were toxic to larvae and pupae of An. stephensi, LC 50 ranged from 2.563 ppm (1st instar larva) to 6.430 ppm (pupa), and Ae. aegypti, LC 50 ranged from 3.231 ppm (1st instar larva) to 7.545 ppm (pupa). MNP IC 50 on P. falciparum were 83.32 μg ml -1 (CQ-s) and 87.47 μg ml -1 (CQ-r). However, the in vivo efficacy of MNP on Plasmodium berghei was low if compared to CQ-based treatments. Moderate cytotoxicity was detected on Vero cells post-treatment with MNP doses lower than 4 μg ml -1 . MNP evaluated at 2-8 μg ml -1 inhibited DEN-2 replication inhibiting the expression of the envelope (E) protein. In conclusion, our findings represent the first report about the use of MNP in medical and veterinary entomology, proposing them as suitable materials to develop reliable tools to combat mosquito-borne diseases.

Avian Plasmodium in Eastern Austrian mosquitoes.

Science.gov (United States)

Schoener, Ellen; Uebleis, Sarah Susanne; Butter, Julia; Nawratil, Michaela; Cuk, Claudia; Flechl, Eva; Kothmayer, Michael; Obwaller, Adelheid G; Zechmeister, Thomas; Rubel, Franz; Lebl, Karin; Zittra, Carina; Fuehrer, Hans-Peter

2017-09-29

Insect vectors, namely mosquitoes (Diptera: Culicidae), are compulsory for malaria parasites (Plasmodium spp.) to complete their life cycle. Despite this, little is known about vector competence of different mosquito species for the transmission of avian malaria parasites. In this study, nested PCR was used to determine Plasmodium spp. occurrence in pools of whole individuals, as well as the diversity of mitochondrial cytochrome b gene sequences in wild-caught mosquitoes sampled across Eastern Austria in 2013-2015. A total of 45,749 mosquitoes in 2628 pools were collected, of which 169 pools (6.43%) comprising 9 mosquito species were positive for avian Plasmodium, with the majority of positives in mosquitoes of Culex pipiens s.l./Culex torrentium. Six different avian Plasmodium lineages were found, the most common were Plasmodium vaughani SYAT05, Plasmodium sp. Linn1 and Plasmodium relictum SGS1. In 2014, mosquitoes of the Culex pipiens complex were genetically identified and Culex pipiens f. pipiens presented with the highest number of avian Plasmodium positives (n = 37; 16.74%). Despite this, the minimum infection rate (MIR) was highest in Culex torrentium (5.36%) and Culex pipiens f. pipiens/f. molestus hybrids (5.26%). During 2014 and 2015, seasonal and annual changes in Plasmodium lineage distribution were also observed. In both years P. vaughani SYAT05 dominated at the beginning of the sampling period to be replaced later in the year by P. relictum SGS1 (2014) and Plasmodium sp. Linn1 (2015). This is the first large-scale study of avian Plasmodium parasites in Austrian mosquitoes. These results are of special interest, because molecular identification of the taxa of the Cx. pipiens complex and Cx. torrentium enabled the determination of Plasmodium prevalence in the different mosquito taxa and hybrids of this complex. Since pools of whole insects were used, it is not possible to assert any vector competence in any of the examined mosquitoes, but the results

Resource Limitation, Controphic Ostracod Density and Larval Mosquito Development.

Directory of Open Access Journals (Sweden)

Raylea Rowbottom

Full Text Available Aquatic environments can be restricted with the amount of available food resources especially with changes to both abiotic and biotic conditions. Mosquito larvae, in particular, are sensitive to changes in food resources. Resource limitation through inter-, and intra-specific competition among mosquitoes are known to affect both their development and survival. However, much less is understood about the effects of non-culicid controphic competitors (species that share the same trophic level. To address this knowledge gap, we investigated and compared mosquito larval development, survival and adult size in two experiments, one with different densities of non-culicid controphic conditions and the other with altered resource conditions. We used Aedes camptorhynchus, a salt marsh breeding mosquito and a prominent vector for Ross River virus in Australia. Aedes camptorhynchus usually has few competitors due to its halo-tolerance and distribution in salt marshes. However, sympatric ostracod micro-crustaceans often co-occur within these salt marshes and can be found in dense populations, with field evidence suggesting exploitative competition for resources. Our experiments demonstrate resource limiting conditions caused significant increases in mosquito developmental times, decreased adult survival and decreased adult size. Overall, non-culicid exploitation experiments showed little effect on larval development and survival, but similar effects on adult size. We suggest that the alterations of adult traits owing to non-culicid controphic competition has potential to extend to vector-borne disease transmission.

Mosquito transmission of the rodent malaria parasite Plasmodium chabaudi

Directory of Open Access Journals (Sweden)

Spence Philip J

2012-12-01

Full Text Available Abstract Background Serial blood passage of Plasmodium increases virulence, whilst mosquito transmission inherently regulates parasite virulence within the mammalian host. It is, therefore, imperative that all aspects of experimental malaria research are studied in the context of the complete Plasmodium life cycle. Methods Plasmodium chabaudi chabaudi displays many characteristics associated with human Plasmodium infection of natural mosquito vectors and the mammalian host, and thus provides a unique opportunity to study the pathogenesis of malaria in a single infection setting. An optimized protocol that permits efficient and reproducible vector transmission of P. c. chabaudi via Anopheles stephensi was developed. Results and conclusions This protocol was utilized for mosquito transmission of genetically distinct P. c. chabaudi isolates, highlighting differential parasite virulence within the mosquito vector and the spectrum of host susceptibility to infection initiated via the natural route, mosquito bite. An apposite experimental system in which to delineate the pathogenesis of malaria is described in detail.

A predator from East Africa that chooses malaria vectors as preferred prey.

Directory of Open Access Journals (Sweden)

Ximena J Nelson

Full Text Available BACKGROUND: All vectors of human malaria, a disease responsible for more than one million deaths per year, are female mosquitoes from the genus Anopheles. Evarcha culicivora is an East African jumping spider (Salticidae that feeds indirectly on vertebrate blood by selecting blood-carrying female mosquitoes as preferred prey. METHODOLOGY/PRINCIPAL FINDINGS: By testing with motionless lures made from mounting dead insects in lifelike posture on cork discs, we show that E. culicivora selects Anopheles mosquitoes in preference to other mosquitoes and that this predator can identify Anopheles by static appearance alone. Tests using active (grooming virtual mosquitoes rendered in 3-D animation show that Anopheles' characteristic resting posture is an important prey-choice cue for E. culicivora. Expression of the spider's preference for Anopheles varies with the spider's size, varies with its prior feeding condition and is independent of the spider gaining a blood meal. CONCLUSIONS/SIGNIFICANCE: This is the first experimental study to show that a predator of any type actively chooses Anopheles as preferred prey, suggesting that specialized predators having a role in the biological control of disease vectors is a realistic possibility.

Environmental management of mosquito-borne viruses in Rhode Island

Science.gov (United States)

Ginsberg, Howard S.; Gettman, Alan; Becker, Elisabeth; Bandyopadhyay, Ananda S.; LeBrun, Roger A.

2013-01-01

West Nile Virus (WNV) and Eastern Equine Encephalitis Virus (EEEV) are both primarily bird viruses, which can be transmitted by several mosquito species. Differences in larval habitats, flight, and biting patterns of the primary vector species result in substantial differences in epidemiology, with WNV more common, primarily occurring in urban areas, and EEEV relatively rare, typically occurring near swamp habitats. The complex transmission ecology of these viruses complicates prediction of disease outbreaks. The Rhode Island Department of Environmental Management (DEM) and Department of Health (DoH) provide prevention assistance to towns and maintain a mosquito surveillance program to identify potential disease risk. Responses to potential outbreaks follow a protocol based on surveillance results, assessment of human risk, and technical consultation.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Avian phenotypic traits related to feeding preferences in two Culex mosquitoes

Science.gov (United States)

Yan, Jiayue; Gangoso, Laura; Martínez-de la Puente, Josué; Soriguer, Ramón; Figuerola, Jordi

2017-10-01

Host choice by mosquitoes affects the transmission dynamics of vector-borne infectious diseases. Although asymmetries in mosquito attraction to vertebrate species have been reported, the relative importance of host characteristics in mosquito blood-feeding behavior is still poorly studied. Here, we investigate the relationship between avian phenotypic traits—in particular, morphometry, plumage coloration, and nesting and roosting behavior—and the blood-feeding patterns in two common Culex mosquito species on a North American avian community. Forage ratios of the mosquito species were unrelated to the phylogenetic relationships among bird species. Culex pipiens fed preferably on birds with lighter-colored plumage and longer tarsi; furthermore, solitary roosting avian species were both bitten by Cx. pipiens and Cx. restuans more often than expected. These associations may be explained by greater mosquito attraction towards larger birds with a greater color contrast against the background. Although communally roosting birds may release more cues and attract more mosquitoes, individuals may in fact receive fewer bites due to the encounter-dilution effect. Mosquito feeding behavior is a highly complex phenomenon, and our results may improve understanding of the non-random interaction between birds and mosquitoes in natural communities.

Host-feeding patterns of Culex pipiens and other potential mosquito vectors (Diptera: Culicidae) of West Nile virus (Flaviviridae) collected in Portugal.

Science.gov (United States)

Osório, Hugo Costa; Zé-Zé, Líbia; Alves, Maria João

2012-05-01

The host blood-feeding patterns of mosquito vectors affects the likelihood of human exposure to zoonotic pathogens, including West Nile Virus (family Flaviviridae, genus Flavivirus, WNV). In Portugal, data are unavailable regarding the blood-feeding habits of common mosquito species, including Culex pipiens L., considered the primary vector of WNV to humans. The sources of bloodmeals in 203 blood-fed mosquitoes of nine species collected from June 2007 to November 2010 in 34 Portuguese counties were analyzed by sequencing cytochrome-b partial fragments. Cx. pipiens was the most common species collected and successfully analyzed (n = 135/78). In addition, blood-fed females of the following species were analyzed: Ochlerotatus caspius Pallas (n = 20), Culex theileri Theobald (n = 16), Anopheles maculipennis s.l. Meigen (n = 10), Culiseta longiareolata Macquart (n = 7), Aedes aegypti L. (n = 6), Culex perexiguus Theobald (n = 3), Culiseta annulata Schrank (n = 3), and Ochlerotatus detritus Haliday (n = 3). The Cx. pipiens mosquitoes fed predominantly on birds (n = 55/78, 70.5%), with a high diversity of avian species used as hosts, although human blood was identified in 18 specimens (18/78, 23.1%). No significant differences were found between the host-feeding patterns of blood-fed Cx. pipiens collected in residential and nonresidential habitats. The occurrence of human derived blood meals and the presence of a mix avian-human bloodmeal accordingly suggest this species as a potential vector of WNV. Therefore, in Portugal, Cx. pipiens may play a role both in the avian-to-avian enzootic WNV cycle and in the avian-to-mammal transmission. In this context, the identity of Cx. pipiens (considering the forms molestus and pipiens) and the potential consequence on feeding behavior and WNV transmission are discussed.

Crowdsourcing methodology: establishing the Cervid Disease Network and the North American Mosquito Project.

Science.gov (United States)

Cohnstaedt, Lee W; Snyder, Darren; Maki, Elin; Schafer, Shawn

2016-06-30

Crowdsourcing is obtaining needed services, ideas, or content by soliciting contributions from a large group of people. This new method of acquiring data works well for single reports, but fails when long-term data collection is needed, mainly due to reporting fatigue or failure of repeated sampling by individuals. To establish a crowdsourced collections network researchers must recruit, reward, and retain contributors to the project. These 3 components of crowdsourcing are discussed using the United States Department of Agriculture social networks, the Cervid Disease Network, and the North American Mosquito Project. The North American Mosquito Project is a large network of professional mosquito control districts and public health agencies, which collects mosquito specimens for genetic studies. The Cervid Disease Network is a crowd-sourced disease monitoring system, which uses voluntary sentinel farms or wildlife programs throughout the United States of America to report the onset and severity of diseases in local areas for pathogen surveillance studies.

Recommendation on vectors and vector-transmitted diseases

OpenAIRE

Netherlands Food and Consumer Product Safety Authority

2009-01-01

In view of their increasing risk of introduction and their possible implications in causing major disease outbreaks, vectors, as well as vector-transmitted diseases like dengue, West Nile disease, Lyme disease and bluetongue need to be recognised as a threat to public and animal health and to the economy, also in the Netherlands. There has been an increase in the incidence of these diseases in the past two to three decades. Climate changes and changes in the use of land, water managemen...

International network for capacity building for the control of emerging viral vector-borne zoonotic diseases: ARBO-ZOONET.

Science.gov (United States)

Ahmed, J; Bouloy, M; Ergonul, O; Fooks, Ar; Paweska, J; Chevalier, V; Drosten, C; Moormann, R; Tordo, N; Vatansever, Z; Calistri, P; Estrada-Pena, A; Mirazimi, A; Unger, H; Yin, H; Seitzer, U

2009-03-26

Arboviruses are arthropod-borne viruses, which include West Nile fever virus (WNFV), a mosquito-borne virus, Rift Valley fever virus (RVFV), a mosquito-borne virus, and Crimean-Congo haemorrhagic fever virus (CCHFV), a tick-borne virus. These arthropod-borne viruses can cause disease in different domestic and wild animals and in humans, posing a threat to public health because of their epidemic and zoonotic potential. In recent decades, the geographical distribution of these diseases has expanded. Outbreaks of WNF have already occurred in Europe, especially in the Mediterranean basin. Moreover, CCHF is endemic in many European countries and serious outbreaks have occurred, particularly in the Balkans, Turkey and Southern Federal Districts of Russia. In 2000, RVF was reported for the first time outside the African continent, with cases being confirmed in Saudi Arabia and Yemen. This spread was probably caused by ruminant trade and highlights that there is a threat of expansion of the virus into other parts of Asia and Europe. In the light of global warming and globalisation of trade and travel, public interest in emerging zoonotic diseases has increased. This is especially evident regarding the geographical spread of vector-borne diseases. A multi-disciplinary approach is now imperative, and groups need to collaborate in an integrated manner that includes vector control, vaccination programmes, improved therapy strategies, diagnostic tools and surveillance, public awareness, capacity building and improvement of infrastructure in endemic regions.

An entomological review of invasive mosquitoes in Europe.

Science.gov (United States)

Medlock, J M; Hansford, K M; Versteirt, V; Cull, B; Kampen, H; Fontenille, D; Hendrickx, G; Zeller, H; Van Bortel, W; Schaffner, F

2015-12-01

Among the invasive mosquitoes registered all over the world, Aedes species are particularly frequent and important. As several of them are potential vectors of disease, they present significant health concerns for 21st century Europe. Five species have established in mainland Europe, with two (Aedes albopictus and Aedes japonicus) becoming widespread and two (Ae. albopictus and Aedes aegypti) implicated in disease transmission to humans in Europe. The routes of importation and spread are often enigmatic, the ability to adapt to local environments and climates are rapid, and the biting nuisance and vector potential are both an ecomonic and public health concern. Europeans are used to cases of dengue and chikungunya in travellers returning from the tropics, but the threat to health and tourism in mainland Europe is substantive. Coupled to that are the emerging issues in the European overseas territorities and this paper is the first to consider the impacts in the remoter outposts of Europe. If entomologists and public health authorities are to address the spread of these mosquitoes and mitigate their health risks they must first be prepared to share information to better understand their biology and ecology, and share data on their distribution and control successes. This paper focusses in greater detail on the entomological and ecological aspects of these mosquitoes to assist with the risk assessment process, bringing together a large amount of information gathered through the ECDC VBORNET project.

Ovicidal, larvicidal and adulticidal properties of Asparagus racemosus (Willd.) (Family: Asparagaceae) root extracts against filariasis (Culex quinquefasciatus), dengue (Aedes aegypti) and malaria (Anopheles stephensi) vector mosquitoes (Diptera: Culicidae).

Science.gov (United States)

Govindarajan, Marimuthu; Sivakumar, Rajamohan

2014-04-01

Several diseases are associated to the mosquito-human interaction. Mosquitoes are the carriers of severe and well-known illnesses such as malaria, arboviral encephalitis, dengue fever, chikungunya fever, West Nile virus and yellow fever. These diseases produce significant morbidity and mortality in humans and livestock around the world. The present investigation was undertaken to study the ovicidal, larvicidal and adulticidal activities of crude hexane, ethyl acetate, benzene, chloroform and methanol extracts of root of Asparagus racemosus were assayed for their toxicity against three important vector mosquitoes, viz., Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi (Diptera: Culicidae). The mean percent hatchability of the eggs was observed after 48 h post-treatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. All the five solvent extracts showed moderate ovicidal activity; however, the methanol extract showed the highest ovicidal activity. The methanol extract of Asparagus racemosus against Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi exerted 100% mortality (zero hatchability) at 375, 300 and 225 ppm, respectively. Control eggs showed 99-100% hatchability. The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in methanol extract of root of Asparagus racemosus against the larvae of Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi with the LC50 and LC90 values were 115.13, 97.71 and 90.97 ppm and 210.96, 179.92, and 168.82 ppm, respectively. The adult mortality was observed after 24 h recovery period. The plant crude extracts showed dose-dependent mortality. At higher concentrations, the adult showed restless movement for some times with abnormal wagging and then died. Among the extracts tested, the highest adulticidal activity was observed in

Evaluating the Vector Control Potential of the In2Care® Mosquito Trap Against Aedes aegypti and Aedes albopictus Under Semifield Conditions in Manatee County, Florida.

Science.gov (United States)

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.

West Nile Virus: High Transmission Rate in North-Western European Mosquitoes Indicates Its Epidemic Potential and Warrants Increased Surveillance.

Directory of Open Access Journals (Sweden)

Jelke J Fros

Full Text Available West Nile virus (WNV is a highly pathogenic flavivirus transmitted by Culex spp. mosquitoes. In North America (NA, lineage 1 WNV caused the largest outbreak of neuroinvasive disease to date, while a novel pathogenic lineage 2 strain circulates in southern Europe. To estimate WNV lineage 2 epidemic potential it is paramount to know if mosquitoes from currently WNV-free areas can support further spread of this epidemic.We assessed WNV vector competence of Culex pipiens mosquitoes originating from north-western Europe (NWE in direct comparison with those from NA. We exposed mosquitoes to infectious blood meals of lineage 1 or 2 WNV and determined the infection and transmission rates. We explored reasons for vector competence differences by comparing intrathoracic injection versus blood meal infection, and we investigated the influence of temperature. We found that NWE mosquitoes are highly competent for both WNV lineages, with transmission rates up to 25%. Compared to NA mosquitoes, transmission rates for lineage 2 WNV were significantly elevated in NWE mosquitoes due to better virus dissemination from the midgut and a shorter extrinsic incubation time. WNV infection rates further increased with temperature increase.Our study provides experimental evidence to indicate markedly different risk levels between both continents for lineage 2 WNV transmission and suggests a degree of genotype-genotype specificity in the interaction between virus and vector. Our experiments with varying temperatures explain the current localized WNV activity in southern Europe, yet imply further epidemic spread throughout NWE during periods with favourable climatic conditions. This emphasizes the need for intensified surveillance of virus activity in current WNV disease-free regions and warrants increased awareness in clinics throughout Europe.

A reduce and replace strategy for suppressing vector-borne diseases: insights from a stochastic, spatial model.

Directory of Open Access Journals (Sweden)

Kenichi W Okamoto

Full Text Available Two basic strategies have been proposed for using transgenic Aedes aegypti mosquitoes to decrease dengue virus transmission: population reduction and population replacement. Here we model releases of a strain of Ae. aegypti carrying both a gene causing conditional adult female mortality and a gene blocking virus transmission into a wild population to assess whether such releases could reduce the number of competent vectors. We find this "reduce and replace" strategy can decrease the frequency of competent vectors below 50% two years after releases end. Therefore, this combined approach appears preferable to releasing a strain carrying only a female-killing gene, which is likely to merely result in temporary population suppression. However, the fixation of anti-pathogen genes in the population is unlikely. Genetic drift at small population sizes and the spatially heterogeneous nature of the population recovery after releases end prevent complete replacement of the competent vector population. Furthermore, releasing more individuals can be counter-productive in the face of immigration by wild-type mosquitoes, as greater population reduction amplifies the impact wild-type migrants have on the long-term frequency of the anti-pathogen gene. We expect the results presented here to give pause to expectations for driving an anti-pathogen construct to fixation by relying on releasing individuals carrying this two-gene construct. Nevertheless, in some dengue-endemic environments, a spatially heterogeneous decrease in competent vectors may still facilitate decreasing disease incidence.

The effect of deltamethrin-treated net fencing around cattle enclosures on outdoor-biting mosquitoes in Kumasi, Ghana.

Directory of Open Access Journals (Sweden)

Marta Ferreira Maia

Full Text Available Classic vector control strategies target mosquitoes indoors as the main transmitters of malaria are indoor-biting and -resting mosquitoes. However, the intensive use of insecticide-treated bed-nets (ITNs and indoor residual spraying have put selective pressure on mosquitoes to adapt in order to obtain human blood meals. Thus, early-evening and outdoor vector activity is becoming an increasing concern. This study assessed the effect of a deltamethrin-treated net (100 mg/m(2 attached to a one-meter high fence around outdoor cattle enclosures on the number of mosquitoes landing on humans. Mosquitoes were collected from four cattle enclosures: Pen A - with cattle and no net; B - with cattle and protected by an untreated net; C - with cattle and protected by a deltamethrin-treated net; D - no cattle and no net. A total of 3217 culicines and 1017 anophelines were collected, of which 388 were Anopheles gambiae and 629 An. ziemanni. In the absence of cattle nearly 3 times more An. gambiae (p<0.0001 landed on humans. The deltamethrin-treated net significantly reduced (nearly three-fold, p<0.0001 culicine landings inside enclosures. The sporozoite rate of the zoophilic An. ziemanni, known to be a secondary malaria vector, was as high as that of the most competent vector An. gambiae; raising the potential of zoophilic species as secondary malaria vectors. After deployment of the ITNs a deltamethrin persistence of 9 months was observed despite exposure to African weather conditions. The outdoor use of ITNs resulted in a significant reduction of host-seeking culicines inside enclosures. Further studies investigating the effectiveness and spatial repellence of ITNs around other outdoor sites, such as bars and cooking areas, as well as their direct effect on vector-borne disease transmission are needed to evaluate its potential as an appropriate outdoor vector control tool for rural Africa.

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

Science.gov (United States)

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

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

Directory of Open Access Journals (Sweden)

Hugo Costa Osório

2018-04-01

Full Text Available 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.

The interplay between mosquitoes, entomopathogens and symbiotic microbes: A niche for the development of novel microbial-derived vector control strategies

Science.gov (United States)

The current outbreak of Zika virus in the Americas has highlighted the need for improved methods of control. This concern is exacerbated if we consider that all three major arboviruses (Zika, dengue, and chikungunya virus) are transmitted efficiently by two wide spread mosquito vectors: Aedes aegypt...

Comparative susceptibility to permethrin of two Anopheles gambiae s.l. populations from Southern Benin, regarding mosquito sex, physiological status, and mosquito age

Directory of Open Access Journals (Sweden)

Nazaire Aïzoun

2014-04-01

Conclusions: The resistance is a hereditary and dynamic phenomenon which can be due to metabolic mechanisms like overproduction of detoxifying enzymes activity. Many factors influence vector susceptibility to insecticide. Among these factors, there are mosquito sex, mosquito age, its physiological status. Therefore, it is useful to respect the World Health Organization criteria in the assessment of insecticide susceptibility tests in malaria vectors. Otherwise, susceptibility testing is conducted using unfed female mosquitoes aged 3-5 days old. Tests should also be carried out at (25±2 °C and (80±10% relative humidity.

Survey of UK horse owners' knowledge of equine arboviruses and disease vectors.

Science.gov (United States)

Chapman, Gail Elaine; Baylis, Matthew; Archer, Debra C

2018-05-15

Increased globalisation and climate change have led to concern about the increasing risk of arthropod-borne virus (arbovirus) outbreaks globally. An outbreak of equine arboviral disease in northern Europe could impact significantly on equine welfare, and result in economic losses. Early identification of arboviral disease by horse owners may help limit disease spread. In order to determine what horse owners understand about arboviral diseases of horses and their vectors, the authors undertook an open, cross-sectional online survey of UK horse owners. The questionnaire was distributed using social media and a press release and was active between May and July 2016. There were 466 respondents, of whom 327 completed the survey in full. High proportions of respondents correctly identified photographic images of biting midges (71.2 per cent) and mosquitoes (65.4 per cent), yet few were aware that they transmit equine infectious diseases (31.4 per cent and 35.9 per cent, respectively). Of the total number of respondents, only 7.4 per cent and 16.2 per cent correctly named a disease transmitted by biting midges and mosquitoes, respectively. Only 13.1 per cent and 12.5 per cent of participants identified specific clinical signs of African horse sickness (AHS) and West Nile virus (WNV), respectively. This study demonstrates that in the event of heightened disease risk educational campaigns directed towards horse owners need to be implemented, focussing on disease awareness, clinical signs and effective disease prevention strategies. © British Veterinary Association (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Heritable strategies for controlling insect vectors of disease.

Science.gov (United States)

Burt, Austin

2014-01-01

Mosquito-borne diseases are causing a substantial burden of mortality, morbidity and economic loss in many parts of the world, despite current control efforts, and new complementary approaches to controlling these diseases are needed. One promising class of new interventions under development involves the heritable modification of the mosquito by insertion of novel genes into the nucleus or of Wolbachia endosymbionts into the cytoplasm. Once released into a target population, these modifications can act to reduce one or more components of the mosquito population's vectorial capacity (e.g. the number of female mosquitoes, their longevity or their ability to support development and transmission of the pathogen). Some of the modifications under development are designed to be self-limiting, in that they will tend to disappear over time in the absence of recurrent releases (and hence are similar to the sterile insect technique, SIT), whereas other modifications are designed to be self-sustaining, spreading through populations even after releases stop (and hence are similar to traditional biological control). Several successful field trials have now been performed with Aedes mosquitoes, and such trials are helping to define the appropriate developmental pathway for this new class of intervention.

Vector movement underlies avian malaria at upper elevation in Hawaii: implications for transmission of human malaria.

Science.gov (United States)

Freed, Leonard A; Cann, Rebecca L

2013-11-01

With climate warming, malaria in humans and birds at upper elevations is an emerging infectious disease because development of the parasite in the mosquito vector and vector life history are both temperature dependent. An enhanced-mosquito-movement model from climate warming predicts increased transmission of malaria at upper elevation sites that are too cool for parasite development in the mosquito vector. We evaluate this model with avian malaria (Plasmodium relictum) at 1,900-m elevation on the Island of Hawaii, with air temperatures too low for sporogony in the vector (Culex quinquefasciatus). On a well-defined site over a 14-year period, 10 of 14 species of native and introduced birds became infected, several epizootics occurred, and the increase in prevalence was driven more by resident species than by mobile species that could have acquired their infections at lower elevations. Greater movement of infectious mosquitoes from lower elevations now permits avian malaria to spread at 1,900 m in Hawaii, in advance of climate warming at that elevation. The increase in malaria at upper elevations due to dispersal of infectious mosquitoes is a real alternative to temperature for the increased incidence of human malaria in tropical highlands.

Venezuelan equine encephalitis emergence: Enhanced vector infection from a single amino acid substitution in the envelope glycoprotein

Science.gov (United States)

Brault, Aaron C.; Powers, Ann M.; Ortiz, Diana; Estrada-Franco, Jose G.; Navarro-Lopez, Roberto; Weaver, Scott C.

2004-01-01

In 1993 and 1996, subtype IE Venezuelan equine encephalitis (VEE) virus caused epizootics in the Mexican states of Chiapas and Oaxaca. Previously, only subtype IAB and IC VEE virus strains had been associated with major outbreaks of equine and human disease. The IAB and IC epizootics are believed to emerge via adaptation of enzootic (sylvatic, equine-avirulent) strains for high titer equine viremia that results in efficient infection of mosquito vectors. However, experimental equine infections with subtype IE equine isolates from the Mexican outbreaks demonstrated neuro-virulence but little viremia, inconsistent with typical VEE emergence mechanisms. Therefore, we hypothesized that changes in the mosquito vector host range might have contributed to the Mexican emergence. To test this hypothesis, we evaluated the susceptibility of the most abundant mosquito in the deforested Pacific coastal locations of the VEE outbreaks and a proven epizootic vector, Ochlerotatus taeniorhynchus. The Mexican epizootic equine isolates exhibited significantly greater infectivity compared with closely related enzootic strains, supporting the hypothesis that adaptation to an efficient epizootic vector contributed to disease emergence. Reverse genetic studies implicated a Ser → Asn substitution in the E2 envelope glycoprotein as the major determinant of the increased vector infectivity phenotype. Our findings underscore the capacity of RNA viruses to alter their vector host range through minor genetic changes, resulting in the potential for disease emergence. PMID:15277679

Pond dyes are Culex mosquito oviposition attractants

Directory of Open Access Journals (Sweden)

Natali Ortiz Perea

2017-05-01

Full Text Available Background British mosquito population distribution, abundance, species composition and potential for mosquito disease transmission are intimately linked to the physical environment. The presence of ponds and water storage can significantly increase the density of particular mosquito species in the garden. Culex pipiens is the mosquito most commonly found in UK gardens and a potential vector of West Nile Virus WNV, although the current risk of transmission is low. However any factors that significantly change the distribution and population of C. pipiens are likely to impact subsequent risk of disease transmission. Pond dyes are used to control algal growth and improve aesthetics of still water reflecting surrounding planting. However, it is well documented that females of some species of mosquito prefer to lay eggs in dark water and/or containers of different colours and we predict that dyed ponds will be attractive to Culex mosquitoes. Methods Black pond dye was used in oviposition choice tests using wild-caught gravid C. pipiens. Larvae from wild-caught C. pipiens were also reared in the pond dye to determine whether it had any impact on survival. An emergence trap caught any adults that emerged from the water. Water butts (80 L were positioned around university glasshouses and woodland and treated with black pond dye or left undyed. Weekly sampling over a six month period through summer and autumn was performed to quantified numbers of larvae and pupae in each treatment and habitat. Results Gravid female Culex mosquitoes preferred to lay eggs in dyed water. This was highly significant in tests conducted under laboratory conditions and in a semi-field choice test. Despite this, survivorship in black dyed water was significantly reduced compared to undyed water. Seasonal analysis of wild larval and pupal numbers in two habitats with and without dye showed no impact of dye but a significant impact of season and habitat. Mosquitoes were more

The entomopathogenic fungus Beauveria bassiana reduces instantaneous blood feeding in wild multi-insecticide-resistant Culex quinquefasciatus mosquitoes in Benin, West Africa

Directory of Open Access Journals (Sweden)

Howard Annabel FV

2010-09-01

Full Text Available Abstract Background Mosquito-borne diseases are still a major health risk in many developing countries, and the emergence of multi-insecticide-resistant mosquitoes is threatening the future of vector control. Therefore, new tools that can manage resistant mosquitoes are required. Laboratory studies show that entomopathogenic fungi can kill insecticide-resistant malaria vectors but this needs to be verified in the field. Methods The present study investigated whether these fungi will be effective at infecting, killing and/or modifying the behaviour of wild multi-insecticide-resistant West African mosquitoes. The entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana were separately applied to white polyester window netting and used in combination with either a permethrin-treated or untreated bednet in an experimental hut trial. Untreated nets were used because we wanted to test the effect of fungus alone and in combination with an insecticide to examine any potential additive or synergistic effects. Results In total, 1125 female mosquitoes were collected during the hut trial, mainly Culex quinquefasciatus Say. Unfortunately, not enough wild Anopheles gambiae Giles were collected to allow the effect the fungi may have on this malaria vector to be analysed. None of the treatment combinations caused significantly increased mortality of Cx. quinquefasciatus when compared to the control hut. The only significant behaviour modification found was a reduction in blood feeding by Cx. quinquefasciatus, caused by the permethrin and B. bassiana treatments, although no additive effect was seen in the B. bassiana and permethrin combination treatment. Beauveria bassiana did not repel blood foraging mosquitoes either in the laboratory or field. Conclusions This is the first time that an entomopathogenic fungus has been shown to reduce blood feeding of wild mosquitoes. This behaviour modification indicates that B. bassiana could potentially be a new

Genetic manipulation of endosymbionts to control vector and vector borne diseases

Directory of Open Access Journals (Sweden)

Jay Prakash Gupta

Full Text Available Vector borne diseases (VBD are on the rise because of failure of the existing methods of control of vector and vector borne diseases and the climate change. A steep rise of VBDs are due to several factors like selection of insecticide resistant vector population, drug resistant parasite population and lack of effective vaccines against the VBDs. Environmental pollution, public health hazard and insecticide resistant vector population indicate that the insecticides are no longer a sustainable control method of vector and vector-borne diseases. Amongst the various alternative control strategies, symbiont based approach utilizing endosymbionts of arthropod vectors could be explored to control the vector and vector borne diseases. The endosymbiont population of arthropod vectors could be exploited in different ways viz., as a chemotherapeutic target, vaccine target for the control of vectors. Expression of molecules with antiparasitic activity by genetically transformed symbiotic bacteria of disease-transmitting arthropods may serve as a powerful approach to control certain arthropod-borne diseases. Genetic transformation of symbiotic bacteria of the arthropod vector to alter the vector’s ability to transmit pathogen is an alternative means of blocking the transmission of VBDs. In Indian scenario, where dengue, chikungunya, malaria and filariosis are prevalent, paratransgenic based approach can be used effectively. [Vet World 2012; 5(9.000: 571-576

The Potential Use of Wolbachia-Based Mosquito Biocontrol Strategies for Japanese Encephalitis.

Directory of Open Access Journals (Sweden)

Claire L Jeffries

Full Text Available Japanese encephalitis virus (JEV is a zoonotic pathogen transmitted by the infectious bite of Culex mosquitoes. The virus causes the development of the disease Japanese encephalitis (JE in a small proportion of those infected, predominantly affecting children in eastern and southern Asia. Annual JE incidence estimates range from 50,000-175,000, with 25%-30% of cases resulting in mortality. It is estimated that 3 billion people live in countries in which JEV is endemic. The virus exists in an enzootic transmission cycle, with mosquitoes transmitting JEV between birds as reservoir hosts and pigs as amplifying hosts. Zoonotic infection occurs as a result of spillover events from the main transmission cycle. The reservoir avian hosts include cattle egrets, pond herons, and other species of water birds belonging to the family Ardeidae. Irrigated rice fields provide an ideal breeding ground for mosquitoes and attract migratory birds, maintaining the transmission of JEV. Although multiple vaccines have been developed for JEV, they are expensive and require multiple doses to maintain efficacy and immunity. As humans are a "dead-end" host for the virus, vaccination of the human population is unlikely to result in eradication. Therefore, vector control of the principal mosquito vector, Culex tritaeniorhynchus, represents a more promising strategy for reducing transmission. Current vector control strategies include intermittent irrigation of rice fields and space spraying of insecticides during outbreaks. However, Cx. Tritaeniorhynchus is subject to heavy exposure to pesticides in rice fields, and as a result, insecticide resistance has developed. In recent years, significant advancements have been made in the potential use of the bacterial endosymbiont Wolbachia for mosquito biocontrol. The successful transinfection of Wolbachia strains from Drosophila flies to Aedes (Stegomyia mosquitoes has resulted in the generation of "dengue-refractory" mosquito

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

Directory of Open Access Journals (Sweden)

Samir Mainali

2017-03-01

Full Text Available (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

Fauna and Larval Habitats of Mosquitoes (Diptera: Culicidae of West Azerbaijan Province, Northwestern Iran.

Directory of Open Access Journals (Sweden)

Farahnaz Khoshdel-Nezamiha

2014-12-01

Full Text Available Several important diseases are transmitted by mosquitoes. Despite of the potential of the occurrence of some mosquito-borne diseases such as West Nile, dirofilariasis and malaria in the region, there is no recent study of mosquitoes in West Azerbaijan Province. The aim of this investigation was to study the fauna, composition and distribution of mosquitoes and the characteristics of their larval habitats in this province.Larvae and adult collections were carried out from different habitats using the standard methods in twenty five localities of seven counties across West Azerbaijan Province.Overall, 1569 mosquitoes including 1336 larvae and 233 adults were collected from 25 localities. The details of geographical properties were recorded. Five genera along with 12 species were collected and identified including: Anopheles claviger, An. maculipennis s.l., An. superpictus, Culex pipiens, Cx. theileri, Cx. modestus, Cx. hortensis, Cx. mimeticus, Culiseta Longiareolata, Ochlerotatus caspius s.l., Oc. geniculatus and Uranotaenia unguiculata. This is the first record of Oc. geniculatus in the province.Due to the geographical location of the West Azerbaijan Province, it comprises different climatic condition which provides suitable environment for the establishment of various species of mosquitoes. The solidarity geographical, cultural and territorial exchanges complicate the situation of the province and its vectors as a threat for future and probable epidemics of mosquito-borne diseases.

Mammal decline, linked to invasive Burmese python, shifts host use of vector mosquito towards reservoir hosts of a zoonotic disease.

Science.gov (United States)

Hoyer, Isaiah J; Blosser, Erik M; Acevedo, Carolina; Thompson, Anna Carels; Reeves, Lawrence E; Burkett-Cadena, Nathan D

2017-10-01

Invasive apex predators have profound impacts on natural communities, yet the consequences of these impacts on the transmission of zoonotic pathogens are unexplored. Collapse of large- and medium-sized mammal populations in the Florida Everglades has been linked to the invasive Burmese python, Python bivittatus Kuhl. We used historic and current data to investigate potential impacts of these community effects on contact between the reservoir hosts (certain rodents) and vectors of Everglades virus, a zoonotic mosquito-borne pathogen that circulates in southern Florida. The percentage of blood meals taken from the primary reservoir host, the hispid cotton rat, Sigmodon hispidus Say and Ord, increased dramatically (422.2%) from 1979 (14.7%) to 2016 (76.8%), while blood meals from deer, raccoons and opossums decreased by 98.2%, reflecting precipitous declines in relative abundance of these larger mammals, attributed to python predation. Overall species diversity of hosts detected in Culex cedecei blood meals from the Everglades declined by 40.2% over the same period ( H (1979) = 1.68, H (2016) = 1.01). Predictions based upon the dilution effect theory suggest that increased relative feedings upon reservoir hosts translate into increased abundance of infectious vectors, and a corresponding upsurge of Everglades virus occurrence and risk of human exposure, although this was not tested in the current study. This work constitutes the first indication that an invasive predator can increase contact between vectors and reservoirs of a human pathogen and highlights unrecognized indirect impacts of invasive predators. © 2017 The Author(s).

A low-cost mesocosm for the study of behaviour and reproductive potential in Afrotropical mosquito (Diptera: Culicidae) vectors of malaria.

Science.gov (United States)

Jackson, B T; Stone, C M; Ebrahimi, B; Briët, O J T; Foster, W A

2015-03-01

A large-scale mesocosm was constructed and tested for its effectiveness for use in experiments on behaviour, reproduction and adult survivorship in the Afrotropical malaria vector Anopheles gambiae s.s. Giles (Diptera: Culicidae) in temperate climates. The large space (82.69 m(3) ) allowed for semi-natural experiments that increased demand on a mosquito's energetic reserves in an environment of widely distributed resources. A one-piece prefabricated enclosure, made with white netting and vinyl, prevented the ingress of predators and the egress of mosquitoes. Daylight and white materials prompted the mosquitoes to seclude themselves in restricted daytime resting sites and allowed the easy collection of dead bodies so that daily mortality could be assessed accurately using a method that accounts for the loss of a proportion of bodies. Here, daily, age-dependent mortality rates of males and females were estimated using Bayesian Markov chain Monte Carlo simulation. In overnight experiments, mosquitoes successfully located plants and took sugar meals. A 3-week survival trial with a single cohort demonstrated successful mating, blood feeding, oviposition and long life. The relatively low cost of the mesocosm and the performance of the mosquitoes in it make it a viable option for any behavioural or ecological study of tropical mosquitoes in which space and seasonal cold are constraining factors. © 2014 The Royal Entomological Society.

The use of annual killifish in the biocontrol of the aquatic stages of mosquitoes in temporary bodies of fresh water; a potential new tool in vector control

Directory of Open Access Journals (Sweden)

Adrias Araceli Q

2010-05-01

Full Text Available Abstract Background Mosquitoes that breed in temporary pools in remote areas that dry up seasonally are especially difficult to control through chemical or biological means. The annual killifish has been suggested as a means of eradicating the aquatic stages of mosquitoes in transient pools because they can maintain permanent populations in such habitats by undergoing suspended animation or diapause during the embryonic stages to survive periodic drought. However, very little is known about the predatory activity of annual killifish and their usefulness in mosquito control. Results The annual killifish, Nothobranchius guentheri, native to Tanzania, was used in this investigation. Food preference was tested under laboratory conditions by feeding juvenile killifish with 2nd instar mosquito larvae of Culex quinquefasciatus in the presence of alternative food sources, such as rotifers and chironomid larvae. Semi-field tests were conducted by introduction of hibernating killifish embryos and juvenile fish to artificial ponds in an outdoor open environment that allowed natural oviposition of Cx. quinquefasciatus. Food preference studies show that N. guentheri preferred to prey on mosquito larvae than either chironomid or rotifers. When hibernating killifish embryos were added to ponds simultaneously with the addition of freshwater, the embryos hatched and fed on mosquito larval population resulting in complete elimination of the immature stages. The introduction of juvenile fish to ponds with high density of mosquito larvae resulted in total eradication of the mosquito population due to predation by fish. Complete biocontrol of the mosquito larval population was achieved in the presence of 3 fish per m2 of pond surface area. Conclusions The annual killifish provides yet another tool that may be employed in the eradication diseases carried by mosquitoes through vector control, particularly in temporary bodies of freshwater. The fish can be conveniently

iDNA screening: Disease vectors as vertebrate samplers.

Science.gov (United States)

Kocher, Arthur; de Thoisy, Benoit; Catzeflis, François; Valière, Sophie; Bañuls, Anne-Laure; Murienne, Jérôme

2017-11-01

In the current context of global change and human-induced biodiversity decline, there is an urgent need for developing sampling approaches able to accurately describe the state of biodiversity. Traditional surveys of vertebrate fauna involve time-consuming and skill-demanding field methods. Recently, the use of DNA derived from invertebrate parasites (leeches and blowflies) was suggested as a new tool for vertebrate diversity assessment. Bloodmeal analyses of arthropod disease vectors have long been performed to describe their feeding behaviour, for epidemiological purposes. On the other hand, this existing expertise has not yet been applied to investigate vertebrate fauna per se. Here, we evaluate the usefulness of hematophagous dipterans as vertebrate samplers. Blood-fed sand flies and mosquitoes were collected in Amazonian forest sites and analysed using high-throughput sequencing of short mitochondrial markers. Bloodmeal identifications highlighted contrasting ecological features and feeding behaviour among dipteran species, which allowed unveiling arboreal and terrestrial mammals of various body size, as well as birds, lizards and amphibians. Additionally, lower vertebrate diversity was found in sites undergoing higher levels of human-induced perturbation. These results suggest that, in addition to providing precious information on disease vector host use, dipteran bloodmeal analyses may represent a useful tool in the study of vertebrate communities. Although further effort is required to validate the approach and consider its application to large-scale studies, this first work opens up promising perspectives for biodiversity monitoring and eco-epidemiology. © 2017 John Wiley & Sons Ltd.

Disrupting Mosquito Reproduction and Parasite Development for Malaria Control.

Directory of Open Access Journals (Sweden)

Lauren M Childs

2016-12-01

Full Text Available 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.

Spatial repellents on strips of camouflage netting reduce mosquito collections in a field environment

Science.gov (United States)

Barrier treatments can be effective in reducing host seeking mosquito vectors and provide an additional layer of passive defense, reducing disease risk. Devices designed to release spatial repellents or direct application of spatial repellents to artificial surfaces can serve as efficient barriers r...

Community participation in mosquito breeding site control: an interdisciplinary mixed methods study in Curacao

NARCIS (Netherlands)

Elsinga, Jelte; van der Veen, Henry T.; Gerstenbluth, Izzy; Burgerhof, Johannes G. M.; Dijkstra, Arie; Grobusch, Martin P.; Tami, Adriana; Bailey, Ajay

2017-01-01

Background: As the arboviral diseases dengue, chikungunya and Zika emerge in the Americas, so does the need for sustainable vector control policies. To successfully achieve mosquito control, joint efforts of both communities and governments are essential. This study investigates this important, but

A low-cost mesocosm for the study of behaviour and reproductive potential of Afrotropical mosquito (Diptera: Culicidae) vectors of malaria

Science.gov (United States)

Jackson, Bryan T.; Stone, Christopher M.; Ebrahimi, Babak; Briët, Olivier J.T.; Foster, Woodbridge A.

2014-01-01

A large-scale mesocosm was constructed and tested for its effectiveness for experiments on behaviour, reproduction, and adult survivorship of the Afrotropical malaria vector Anopheles gambiae s.s. Giles (Diptera: Culicidae) in temperate climates. The large space (82.69 m3) allowed for semi-natural experiments that increased demand on a mosquito’s energetic reserves in an environment of widely distributed resources. A one-piece prefabricated enclosure, made with white netting and vinyl, prevented the ingress of predators and the egress of mosquitoes. Daylight and white materials prompted the mosquitoes to seclude themselves in restricted daytime resting sites and allowed easy collection of dead bodies so that daily mortality could be assessed accurately, using a method that accounts for a proportion of bodies being lost. Here, daily, age-dependent mortality rates of males and females were estimated using Bayesian Markov Chain Monte Carlo simulation. In overnight experiments, mosquitoes successfully located plants and took sugar meals. A 3-week survival trial with a single-cohort demonstrated successful mating, blood feeding, oviposition, and long life. The relatively low cost of the mesocosm and the performance of the mosquitoes in it make it a viable option for any behavioural or ecological study of tropical mosquitoes where space and seasonal cold are constraining factors. PMID:25294339

Odonate Nymphs: Generalist Predators and their Potential in the Management of Dengue Mosquito, Aedes aegypti (Diptera: Culicidae

Directory of Open Access Journals (Sweden)

Waseem Akram

2016-01-01

Full Text Available Background: Dengue is amongst the most serious mosquito-borne infectious disease with hot spots in tropical and subtropical parts of the world. Unfortunately, no licensed vaccine for the disease is currently available in medicine markets. The only option available is the management of dengue vector mosquito, Aedes aegypti (Diptera: Culicidae.Method: Predatory potential of five odonate nymphs namely Anax parthenope, Bradinopyga geminate, Ischnura forcipata, Rhinocypha quadrimaculata, and Orthetrum sabina were evaluated against the 4th instar larvae of the den­gue vector mosquito, Aedes aegypti, under laboratory conditions. The consumption of the mosquito larvae was eval­uated at three water volume levels viz., 1 liter, 2 liter and 3 liter.Results: The number of Ae. aegypti larvae consumed varied significantly among the five species, and at different levels of water volume (P< 0.01. However, the interaction between odonate nymphs and the water volumes was statistically non-significant (P> 0.05. Ischnura forcipata consumed the highest number of Ae. aegypti larvae (n=56 followed by A. parthenope (n=47 and B. geminate (n=46. The number of larvae consumed was decreased with in­creasing search area or water volume, and the highest predation was observed at 1-liter water volume.Conclusion: The odonate nymphs could be a good source of biological agents for the management of the mosquitoes at larval stages. 

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

Science.gov (United States)

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

Factors influencing stakeholders attitudes toward genetically modified aedes mosquito.

Science.gov (United States)

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.

An overview of mosquitoes and emerging arboviral infections in the Zagreb area, Croatia.

Science.gov (United States)

Klobucar, Ana; Benic, Nikola; Krajcar, Darko; Kosanovic-Licina, Mirjana Lana; Tesic, Vanja; Merdic, Enrih; Vrucina, Ivana; Savic, Vladimir; Barbic, Ljubo; Stevanovic, Vladimir; Pem-Novosel, Iva; Vilibic-Cavlek, Tatjana

2016-12-30

Mosquito control in the Zagreb area has been conducted for many years, whereas the fauna has only been investigated in the last 20 years. So far 30 mosquito species have been detected in the city area. Culex pipiens form molestus is the dominant mosquito species in indoor breeding sites. In forested areas and areas exposed to flooding, the active period is early spring and the dominant species are Ochlerotatus sticticus, Ochlerotatus cantans, Ochlerotatus geniculatus and Aedes vexans. The eudominant mosquito species found in the artificial breeding sites are Culex pipiens and the Asian tiger mosquito, Aedes albopictus. Invasive Ae. albopictus, present in the Zagreb area since 2004, has expanded to a larger area of the city during the last three years. The recent emergence of the human West Nile virus and Usutu virus neuroinvasive disease in Zagreb and its surroundings highlighted the role of mosquitoes as vectors of emerging arboviruses. The paper focuses on mosquito species and arboviral infections detected in humans and animals in the Zagreb area, Croatia.

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

Science.gov (United States)

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

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

Science.gov (United States)

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 (Paegypti mosquitoes were collected using Prokopack aspiration outdoors than indoors (Paegypti bites was highest in urban areas, outdoors and in the afternoon hours. These characteristics have major implications for the possible transmission of arboviral diseases and for the planning of surveillance and control programs. PMID:29261766

Mosquito population regulation and larval source management in heterogeneous environments.

Directory of Open Access Journals (Sweden)

David L Smith

Full Text Available An important question for mosquito population dynamics, mosquito-borne pathogen transmission and vector control is how mosquito populations are regulated. Here we develop simple models with heterogeneity in egg laying patterns and in the responses of larval populations to crowding in aquatic habitats. We use the models to evaluate how such heterogeneity affects mosquito population regulation and the effects of larval source management (LSM. We revisit the notion of a carrying capacity and show how heterogeneity changes our understanding of density dependence and the outcome of LSM. Crowding in and productivity of aquatic habitats is highly uneven unless egg-laying distributions are fine-tuned to match the distribution of habitats' carrying capacities. LSM reduces mosquito population density linearly with coverage if adult mosquitoes avoid laying eggs in treated habitats, but quadratically if eggs are laid in treated habitats and the effort is therefore wasted (i.e., treating 50% of habitat reduces mosquito density by approximately 75%. Unsurprisingly, targeting (i.e. treating a subset of the most productive pools gives much larger reductions for similar coverage, but with poor targeting, increasing coverage could increase adult mosquito population densities if eggs are laid in higher capacity habitats. Our analysis suggests that, in some contexts, LSM models that accounts for heterogeneity in production of adult mosquitoes provide theoretical support for pursuing mosquito-borne disease prevention through strategic and repeated application of modern larvicides.

Modulation of Host Learning in Aedes aegypti Mosquitoes.

Science.gov (United States)

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.

Malaria-induced changes in host odors enhance mosquito attraction.

Science.gov (United States)

De Moraes, Consuelo M; Stanczyk, Nina M; Betz, Heike S; Pulido, Hannier; Sim, Derek G; Read, Andrew F; Mescher, Mark C

2014-07-29

Vector-borne pathogens may alter traits of their primary hosts in ways that influence the frequency and nature of interactions between hosts and vectors. Previous work has reported enhanced mosquito attraction to host organisms infected with malaria parasites but did not address the mechanisms underlying such effects. Here we document malaria-induced changes in the odor profiles of infected mice (relative to healthy individuals) over the course of infection, as well as effects on the attractiveness of infected hosts to mosquito vectors. We observed enhanced mosquito attraction to infected mice during a key period after the subsidence of acute malaria symptoms, but during which mice remained highly infectious. This attraction corresponded to an overall elevation in the volatile emissions of infected mice observed during this period. Furthermore, data analyses--using discriminant analysis of principal components and random forest approaches--revealed clear differences in the composition of the volatile blends of infected and healthy individuals. Experimental manipulation of individual compounds that exhibited altered emission levels during the period when differential vector attraction was observed also elicited enhanced mosquito attraction, indicating that compounds being influenced by malaria infection status also mediate vector host-seeking behavior. These findings provide important insights into the cues that mediate vector attraction to hosts infected with transmissible stages of malaria parasites, as well as documenting characteristic changes in the odors of infected individuals that may have potential value as diagnostic biomarkers of infection.

Integrated Strategies for the Control and Prevention of Dengue Vectors with Particular Reference to Aedes aegypti

Directory of Open Access Journals (Sweden)

Asghar Abbas

2014-01-01

Full Text Available Dengue fever (DF is one of the most threatening vector borne diseases, affecting both humans and animals, causing severe epidemics and has brought the world to take serious steps for its control and prevention. DF is a viral disease transmitted by Aedes mosquitoes. Unfortunately, due to unavailability of vaccine and lack of effective treatment, emphasis is given on its vector control. The only option left for its eradication is to restrict mosquito breeding. This can be achieved by chemical, biological and environment management methods. Use of botanicals is also an alternate and probably most effective approach for controlling DF vector. Community based eradication campaigns including educating people about its prevention and control meseaures and personal prophylaxis also play a vital role to prevent its occurrence. Likewise, use of nanotechnology and micro-emulsion, use of pheromones, insect sterilization techniques has also shown promising results in vector control. Utilization of only one method cannot control this dangerous disease but combination of all above interventions, discussed in the present paper, may prevent the DF vector and ultimately might help in the eradication programs of this disease.

Potential for Co-Infection of a Mosquito-Specific Flavivirus, Nhumirim Virus, to Block West Nile Virus Transmission in Mosquitoes

Directory of Open Access Journals (Sweden)

Silvina Goenaga

2015-11-01

Full Text Available Nhumirim virus (NHUV is an insect-specific virus that phylogenetically affiliates with dual-host mosquito-borne flaviviruses. Previous in vitro co-infection experiments demonstrated prior or concurrent infection of Aedes albopictus C6/36 mosquito cells with NHUV resulted in a 10,000-fold reduction in viral production of West Nile virus (WNV. This interference between WNV and NHUV was observed herein in an additional Ae. albopictus mosquito cell line, C7-10. A WNV 2K peptide (V9M mutant capable of superinfection with a pre-established WNV infection demonstrated a comparable level of interference from NHUV as the parental WNV strain in C6/36 and C7-10 cells. Culex quinquefasciatus and Culex pipiens mosquitoes intrathoracically inoculated with NHUVandWNV, or solely withWNVas a control, were allowed to extrinsically incubate the viruses up to nine and 14 days, respectively, and transmissibility and replication of WNV was determined. The proportion of Cx. quinquefasciatus mosquitoes capable of transmitting WNV was significantly lower for the WNV/NHUV group than the WNV control at seven and nine days post inoculation (dpi, while no differences were observed in the Cx. pipiens inoculation group. By dpi nine, a 40% reduction in transmissibility in mosquitoes from the dual inoculation group was observed compared to the WNV-only control. These data indicate the potential that infection of some Culex spp. vectors with NHUV could serve as a barrier for efficient transmissibility of flaviviruses associated with human disease.

Infection and transmission of Rift Valley fever viruses lacking the NSs and/or NSm genes in mosquitoes: potential role for NSm in mosquito infection.