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Sample records for main mosquito vector

  1. Genetics of Mosquito Vector Competence

    PubMed Central

    Beerntsen, Brenda T.; James, Anthony A.; Christensen, Bruce M.

    2000-01-01

    Mosquito-borne diseases are responsible for significant human morbidity and mortality throughout the world. Efforts to control mosquito-borne diseases have been impeded, in part, by the development of drug-resistant parasites, insecticide-resistant mosquitoes, and environmental concerns over the application of insecticides. Therefore, there is a need to develop novel disease control strategies that can complement or replace existing control methods. One such strategy is to generate pathogen-resistant mosquitoes from those that are susceptible. To this end, efforts have focused on isolating and characterizing genes that influence mosquito vector competence. It has been known for over 70 years that there is a genetic basis for the susceptibility of mosquitoes to parasites, but until the advent of powerful molecular biological tools and protocols, it was difficult to assess the interactions of pathogens with their host tissues within the mosquito at a molecular level. Moreover, it has been only recently that the molecular mechanisms responsible for pathogen destruction, such as melanotic encapsulation and immune peptide production, have been investigated. The molecular characterization of genes that influence vector competence is becoming routine, and with the development of the Sindbis virus transducing system, potential antipathogen genes now can be introduced into the mosquito and their effect on parasite development can be assessed in vivo. With the recent successes in the field of mosquito germ line transformation, it seems likely that the generation of a pathogen-resistant mosquito population from a susceptible population soon will become a reality. PMID:10704476

  2. Improvised microinjection technique for mosquito vectors

    PubMed Central

    Sampath, Kumar S.; Puttaraju, H. P.

    2012-01-01

    Background & objectives: Bio-manipulation technique is of primary importance during the development of transgenic mosquitoes. The study describes the variable factors that influence the viability of medically important mosquito vectors during microinjection. Methods: Three mosquito vectors belonging to the genus Aedes, Anopheles and Culex were microinjected at different developmental stages of their life cycle viz., egg, larvae, pupae and adult. Results: The improvisations revealed an increased survivability of biomanipulated mosquitoes during the embryonic and adult microinjection. The study of injecting larvae and pupae resulted in poor survivability. Interpretation & conclusions: The microinjection protocol was successfully tested on three important mosquito vectors. The critical period after biomanipulation which contributes heavily for the survivability factor was evaluated. The results provide a common protocol for biomanipulation of three mosquito vectors with enhanced survivability. PMID:23391792

  3. Paratransgenesis: a promising new strategy for mosquito vector control.

    PubMed

    Wilke, André Barretto Bruno; Marrelli, Mauro Toledo

    2015-01-01

    The three main mosquito genera, Anopheles, Aedes and Culex, transmit respectively malaria, dengue and lymphatic filariasis. Current mosquito control strategies have proved unsuccessful, and there still is a substantial number of morbidity and mortality from these diseases. Genetic control methods have now arisen as promising alternative strategies, based on two approaches: the replacement of a vector population by disease-refractory mosquitoes and the release of mosquitoes carrying a lethal gene to suppress target populations. However, substantial hurdles and limitations need to be overcome if these methods are to be used successfully, the most significant being that a transgenic mosquito strain is required for every target species, making genetically modified mosquito strategies inviable when there are multiple vector mosquitoes in the same area. Genetically modified bacteria capable of colonizing a wide range of mosquito species may be a solution to this problem and another option for the control of these diseases. In the paratransgenic approach, symbiotic bacteria are genetically modified and reintroduced in mosquitoes, where they express effector molecules. For this approach to be used in practice, however, requires a better understanding of mosquito microbiota and that symbiotic bacteria and effector molecules be identified. Paratransgenesis could prove very useful in mosquito species that are inherently difficult to transform or in sibling species complexes. In this approach, a genetic modified bacteria can act by: (a) causing pathogenic effects in the host; (b) interfering with the host's reproduction; (c) reducing the vector's competence; and (d) interfering with oogenesis and embryogenesis. It is a much more flexible and adaptable approach than the use of genetically modified mosquitoes because effector molecules and symbiotic bacteria can be replaced if they do not achieve the desired result. Paratransgenesis may therefore become an important integrated

  4. Molecular Genetic Manipulation of Vector Mosquitoes

    PubMed Central

    Terenius, Olle; Marinotti, Osvaldo; Sieglaff, Douglas; James, Anthony A.

    2008-01-01

    Genetic strategies for reducing populations of vector mosquitoes or replacing them with those that are not able to transmit pathogens benefit greatly from molecular tools that allow gene manipulation and transgenesis. Mosquito genome sequences and associated EST (Expressed Sequence Tags) databases enable large-scale investigations to provide new insights into evolutionary, biochemical, genetic, metabolic and physiological pathways. Additionally, comparative genomics reveals the bases for evolutionary mechanisms with particular focus on specific interactions between vectors and pathogens. We discuss how this information may be exploited for the optimization of transgenes that interfere with the propagation and development of pathogens in their mosquito hosts. PMID:18996342

  5. Chikungunya virus and its mosquito vectors.

    PubMed

    Higgs, Stephen; Vanlandingham, Dana

    2015-04-01

    Chikungunya virus (CHIKV), a mosquito-borne alphavirus of increasing public health significance, has caused large epidemics in Africa and the Indian Ocean basin; now it is spreading throughout the Americas. The primary vectors of CHIKV are Aedes (Ae.) aegypti and, after the introduction of a mutation in the E1 envelope protein gene, the highly anthropophilic and geographically widespread Ae. albopictus mosquito. We review here research efforts to characterize the viral genetic basis of mosquito-vector interactions, the use of RNA interference and other strategies for the control of CHIKV in mosquitoes, and the potentiation of CHIKV infection by mosquito saliva. Over the past decade, CHIKV has emerged on a truly global scale. Since 2013, CHIKV transmission has been reported throughout the Caribbean region, in North America, and in Central and South American countries, including Brazil, Columbia, Costa Rica, El Salvador, French Guiana, Guatemala, Guyana, Nicaragua, Panama, Suriname, and Venezuela. Closing the gaps in our knowledge of driving factors behind the rapid geographic expansion of CHIKV should be considered a research priority. The abundance of multiple primate species in many of these countries, together with species of mosquito that have never been exposed to CHIKV, may provide opportunities for this highly adaptable virus to establish sylvatic cycles that to date have not been seen outside of Africa. The short-term and long-term ecological consequences of such transmission cycles, including the impact on wildlife and people living in these areas, are completely unknown. PMID:25674945

  6. Culex torrentium Mosquito Role as Major Enzootic Vector Defined by Rate of Sindbis Virus Infection, Sweden, 2009

    PubMed Central

    Verner-Carlsson, Jenny; Larsson, Anders; Ahmed, Raija; Lundkvist, Åke; Lundström, Jan O.

    2015-01-01

    We isolated Sindbis virus (SINV) from the enzootic mosquito vectors Culex torrentium, Cx. pipiens, and Culiseta morsitans collected in an area of Sweden where SINV disease is endemic. The infection rate in Cx. torrentium mosquitoes was exceptionally high (36 infections/1,000 mosquitoes), defining Cx. torrentium as the main enzootic vector of SINV in Scandinavia. PMID:25898013

  7. Genetic elimination of dengue vector mosquitoes

    PubMed Central

    Wise de Valdez, Megan R.; Nimmo, Derric; Betz, John; Gong, Hong-Fei; James, Anthony A.; Alphey, Luke; Black, William C.

    2011-01-01

    An approach based on mosquitoes carrying a conditional dominant lethal gene (release of insects carrying a dominant lethal, RIDL) is being developed to control the transmission of dengue viruses by vector population suppression. A transgenic strain, designated OX3604C, of the major dengue vector, Aedes aegypti, was engineered to have a repressible female-specific flightless phenotype. This strain circumvents the need for radiation-induced sterilization, allows genetic sexing resulting in male-only releases, and permits the release of eggs instead of adult mosquitoes. OX3604C males introduced weekly into large laboratory cages containing stable target mosquito populations at initial ratios of 8.5–10∶1 OX3604C∶target eliminated the populations within 10–20 weeks. These data support the further testing of this strain in contained or confined field trials to evaluate mating competitiveness and environmental and other effects. Successful completion of the field trials should facilitate incorporation of this approach into area-wide dengue control or elimination efforts as a component of an integrated vector management strategy. PMID:21383140

  8. Transcriptome of the adult female malaria mosquito vector Anopheles albimanus

    PubMed Central

    2012-01-01

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

  9. Promoting health education and public awareness about dengue and its mosquito vector in Saudi Arabia.

    PubMed

    Aziz, Al Thabiani; Al-Shami, Salman A; Mahyoub, Jazem A; Hatabbi, Mesed; Ahmad, Abu Hassan; Md Rawi, Che Salmah

    2014-01-01

    Currently, dengue fever is considered as the main health problem in several parts (Mekkah, Jeddah, Jazan and Najran) of Kingdom of Saudi Arabia (KSA) with dramatically increase in the number of cases reported every year. This is associated with obvious ineffectiveness in the recent control and management programs for the mosquito vector (Aedes aegypti). Here, we suggested promoting the health education and public awareness among Saudi people to improve the control of dengue mosquito vector. Several suggestions and recommendations were highlighted here to ensure effectiveness in the future control and management programs of dengue mosquito vector in KSA. PMID:25403705

  10. [Mosquitoes as vectors for exotic pathogens in Germany].

    PubMed

    Becker, N; Krüger, A; Kuhn, C; Plenge-Bönig, A; Thomas, S M; Schmidt-Chanasit, J; Tannich, E

    2014-05-01

    As a result of intensified globalization of international trade and of substantial travel activities, mosquito-borne exotic pathogens are becoming an increasing threat for Europe. In Germany some 50 different mosquito species are known, several of which have vector competence for pathogens. During the last few years a number of zoonotic arboviruses that are pathogenic for humans have been isolated from mosquitoes in Germany including Usutu, Sindbis and Batai viruses. In addition, filarial worms, such as Dirofilaria repens have been repeatedly detected in mosquitoes from the federal state of Brandenburg. Other pathogens, in particular West Nile virus, are expected to emerge sooner or later in Germany as the virus is already circulating in neighboring countries, e.g. France, Austria and the Czech Republic. In upcoming years the risk for arbovirus transmission might increase in Germany due to increased occurrence of new so-called "invasive" mosquito species, such as the Asian bush mosquito Ochlerotatus japonicus or the Asian tiger mosquito Aedes albopictus. These invasive species are characterized by high vector competence for a broad range of pathogens and a preference for human blood meals. For risk assessment, a number of mosquito and pathogen surveillance projects have been initiated in Germany during the last few years; however, mosquito control strategies and plans of action have to be developed and put into place to allow early and efficient action against possible vector-borne epidemics. PMID:24781910

  11. Adult vector control, mosquito ecology and malaria transmission

    PubMed Central

    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.

    2015-01-01

    Background 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. Methods 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. Results 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. Conclusions 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. PMID:25733562

  12. Mosquito vectors and the spread of cancer: an overlooked connection?

    PubMed

    Benelli, Giovanni; Lo Iacono, Annalisa; Canale, Angelo; Mehlhorn, Heinz

    2016-06-01

    Mosquitoes (Diptera: Culicidae) represent a key threat for millions of humans and animals worldwide, vectoring important pathogens and parasites, including malaria, dengue, filariasis, and Zika virus. Besides mosquito-borne diseases, cancers figure among the leading causes of mortality worldwide. It is expected that annual cancer cases will rise from 14 million in 2012 to 22 million within the next two decades. Notably, there are few contrasting evidences of the relationship between cancer and mosquito-borne diseases, with special reference to malaria. However, analogies at the cellular level for the two diseases were reported. Recently, a significant association of malaria incidence with all cancer mortality in 50 USA states was highlighted and may be explained by the ability of Plasmodium to induce suppression of the immune system. However, it was hypothesized that Anopheles vectors may transmit obscure viruses linked with cancer development. The possible activation of cancer pathways by mosquito feeding events is not rare. For instance, the hamster reticulum cell sarcoma can be transmitted through the bites of Aedes aegypti by a transfer of tumor cells. Furthermore, mosquito bites may influence human metabolic pathways following different mechanisms, leading to other viral infections and/or oncogenesis. Hypersensitivity to mosquito bites is routed by a unique pathogenic mechanism linking Epstein-Barr virus infection, allergy, and oncogenesis. During dengue virus infection, high viral titers, macrophage infiltration, and tumor necrosis factor alpha production in the local tissues are the three key important events that lead to hemorrhage. Overall, basic epidemiological knowledge on the relationships occurring between mosquito vector activity and the spread of cancer is urgently needed, as well as detailed information about the ability of Culicidae to transfer viruses or tumor cells among hosts over time. Current evidences on nanodrugs with multipotency against

  13. Surveillance of Rift Valley Fever Virus in Mosquito Vectors of the Republic of Korea.

    PubMed

    Kim, Hyun-Joo; Lyoo, Hye-Rhyoung; Park, Jee-Yong; Choi, Jeong-Soo; Lee, Ji-Youn; Jeoung, Hye-Young; Cho, Yun-Sang; Cho, In-Soo; Yoo, Han Sang

    2016-02-01

    Rift Valley fever (RVF) is an acute mosquito-borne viral zoonotic disease that affects mainly domestic ruminants and humans. RVF virus (RVFV) was first identified in Kenya in 1931 and was reported to be endemic in Africa but has recently spread to the Arabian Peninsula. With increasing climate change and globalization of trade in animals and animal products, there is great concern that the disease will spread worldwide to regions such as Europe, Asia, and the Americas. Although RVFV has not been reported in the Republic of Korea (ROK), the possibility of RVFV introduction is increasing because transmissible mosquito vectors are present and direct flights to Africa were added in 2012. For these reasons, we conducted a surveillance study to detect RVFV in mosquito vectors collected around the airport and harbor from 2012 to 2013. A total of 36,734 mosquitoes were collected and tested by real-time RT-PCR. A total of 1837 mosquito pools were used, and all were confirmed to be negative. This is the first report in the ROK concerning RVFV surveillance in mosquito vectors, and continuous surveillance will be conducted for the early warning of RVFV introduction. PMID:26771529

  14. Devising novel strategies against vector mosquitoes and house flies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 1932, the United States Department of Agriculture established an entomological research laboratory in Orlando, Florida. The initial focus of the program was on investigations of mosquitoes (including malaria vectors under conditions “simulating those of South Pacific jungles”) and other insects ...

  15. Silica nanoparticle: a potential new insecticide for mosquito vector control.

    PubMed

    Barik, Tapan K; Kamaraju, Raghavendra; Gowswami, Arunava

    2012-09-01

    Presently, there is a need for increased efforts to develop newer and effective methods to control mosquito vectors as the existing chemical and biological methods are not as effective as in earlier period owing to different technical and operational reasons. The use of nanomaterial products in various sectors of science including health increased during the last decade. We tested three types of nanosilica, namely lipophilic, hydrophilic and hydrophobic, to assess their larvicidal, pupicidal and growth inhibitor properties and also their influence on oviposition behaviour (attraction/deterrence) of mosquito species that transmit human diseases, namely malaria (Anopheles), yellow fever, chickungunya and dengue (Aedes), lymphatic filariasis and encephalitis (Culex and Aedes). Application of hydrophobic nanosilica at 112.5 ppm was found effective against mosquito species tested. The larvicidal effect of hydrophobic nanosilica on mosquito species tested was in the order of Anopheles stephensi > Aedes aegypti > Culex quinquefasciatus, and the pupicidal effect was in the order of A. stephensi > C. quinquefasciatus > Ae. aegypti. Results of combined treatment of hydrophobic nanosilica with temephos in larvicidal test indicated independent toxic action without any additive effect. This is probably the first report that demonstrated that nanoparticles particularly nanosilica could be used in mosquito vector control. PMID:22565400

  16. Sampling of adult mosquito vectors with Mosquito Magnet Pro in Panaji, Goa, India.

    PubMed

    Korgaonkar, Nandini S; Kumar, Ashwani; Yadav, Rajpal S; Kabadi, Dipak; Dash, Aditya P

    2008-12-01

    For mosquito vector population monitoring, a new commercial trap, Mosquito Magnet Pro (MM-PRO), was tested for its usefulness in Goa, India. Anopheles stephensi was tested for the presence of Plasmodium sporozoite infection in the salivary glands. Using the MM-PRO 24 h a day for 34 days, 2,329 mosquitoes belonging to 16 species were collected. These included 6 species each of the genera Anopheles and Culex, 2 species of Aedes, and 1 each of Mansonia and Armigeres. Most (91%) of the mosquitoes caught were females. Among these the number and percentage of each species were Anopheles stephensi 59 (2.78%), Culex quinquefasciatus 1013 (47.78%), Culex vishnui 551 (26.0%), Mansonia uniformis 216 (10.19%), and Aedes albopictus 1 (0.04%). Of the 54 An. stephensi females tested for the presence of circumsporozoite protein (CSP) by an ELISA technique, 1 was found to be Plasmodium falciparum CSP positive. The MM-PRO device was found useful for mosquito population sampling in the urban setting of Goa. PMID:19181075

  17. Evaluation of vector competence for West Nile virus in Italian Stegomyia albopicta (=Aedes albopictus) mosquitoes.

    PubMed

    Fortuna, C; Remoli, M E; Severini, F; Di Luca, M; Toma, L; Fois, F; Bucci, P; Boccolini, D; Romi, R; Ciufolini, M G

    2015-12-01

    West Nile virus (WNV) is a zoonotic arboviral pathogen transmitted by mosquitoes in a cycle that involves wild birds as reservoir hosts. The virus is responsible for outbreaks of viral encephalitis in humans and horses. In Europe, Culex pipiens (Diptera: Culicidae) is considered to be the main vector of WNV, but other species such as Stegomyia albopicta (=Aedes albopictus) (Diptera: Culicidae) may also act as competent vectors of this virus. Since 2008 human cases of WNV disease have been reported in northeast Italy. In 2011, new areas of southern Italy became involved and a first outbreak of WNV lineage 1 occurred on the island of Sardinia. On the assumption that a potential involvement of St. albopicta in WNV transmission cannot be excluded, and in order to evaluate the competence of this species for the virus, an experimental infection of an St. albopicta laboratory colony, established from mosquitoes collected in Sardinia, was carried out. The results were compared with those obtained in a colony of the main vector Cx. pipiens. The study showed St. albopicta collected on Sardinia to be susceptible to WNV infection, which suggests this Italian mosquito species is able to act as a possible secondary vector, particularly in urban areas where the species reaches high levels of seasonal abundance. PMID:26382099

  18. Culex Tarsalis Mosquitoes as Vectors of Highlands J Virus.

    PubMed

    Borland, Erin M; Ledermann, Jeremy P; Powers, Ann M

    2016-08-01

    Highlands J virus (HJV) is an alphavirus closely related to western equine encephalitis virus (WEEV) and eastern equine encephalitis virus (EEEV). HJV is an avian pathogen with the potential for disruption of poultry operations, but is not known to cause human or equine disease. HJV has only been identified in the eastern United States and is thought to have a transmission cycle similar to that of EEEV involving Culiseta melanura mosquitoes and birds. However, HJV is more genetically similar to WEEV and it remains unclear if it may be transmitted by Culex species mosquitoes like WEEV. Seven strains of HJV were characterized to assess this potential. Phylogenetic analysis of whole genome sequences revealed four distinct HJV lineages (lineages 1-4), and vector competence studies in Cx. tarsalis with four of the HJV strains from different lineages yielded two distinct infection patterns. Lineage 1 strains had low infection rates, while lineages 2 and 4 had significantly higher infection rates similar to those previously published for WEEV. The average mosquito body viral titer was highest at 8 dpi (6.60-7.26 log10 pfu equivalents/body), and head titers at all time points ranged between 6.01 and 6.80 log10 pfu equivalents/head. Nearly 45% of mosquitoes infected with strain AB-80-9 were able to transmit virus in saliva with an average titer of 5.02 log10 pfu equivalents/saliva. A single amino acid difference between high and low infectivity phenotypes was identified at genome position 8605, in the E2 gene. A nonpolar glycine was present in the low infectivity lineage 1 strains, while an acidic glutamic acid was present in the higher infectivity lineage 2 and 4 strains. This study demonstrates HJV transmission by Cx. tarsalis mosquitoes and clearly identifies the potential for transmission in the western United States. Two infection phenotypes were exhibited, indicating the need for further studies to understand Culex species transmission patterns. PMID:27248005

  19. Mosquito genomics. Highly evolvable malaria vectors: the genomes of 16 Anopheles mosquitoes.

    PubMed

    Neafsey, Daniel E; Waterhouse, Robert M; Abai, Mohammad R; Aganezov, Sergey S; Alekseyev, Max A; Allen, James E; Amon, James; Arcà, Bruno; Arensburger, Peter; Artemov, Gleb; Assour, Lauren A; Basseri, Hamidreza; Berlin, Aaron; Birren, Bruce W; Blandin, Stephanie A; Brockman, Andrew I; Burkot, Thomas R; Burt, Austin; Chan, Clara S; Chauve, Cedric; Chiu, Joanna C; Christensen, Mikkel; Costantini, Carlo; Davidson, Victoria L M; Deligianni, Elena; Dottorini, Tania; Dritsou, Vicky; Gabriel, Stacey B; Guelbeogo, Wamdaogo M; Hall, Andrew B; Han, Mira V; Hlaing, Thaung; Hughes, Daniel S T; Jenkins, Adam M; Jiang, Xiaofang; Jungreis, Irwin; Kakani, Evdoxia G; Kamali, Maryam; Kemppainen, Petri; Kennedy, Ryan C; Kirmitzoglou, Ioannis K; Koekemoer, Lizette L; Laban, Njoroge; Langridge, Nicholas; Lawniczak, Mara K N; Lirakis, Manolis; Lobo, Neil F; Lowy, Ernesto; MacCallum, Robert M; Mao, Chunhong; Maslen, Gareth; Mbogo, Charles; McCarthy, Jenny; Michel, Kristin; Mitchell, Sara N; Moore, Wendy; Murphy, Katherine A; Naumenko, Anastasia N; Nolan, Tony; Novoa, Eva M; O'Loughlin, Samantha; Oringanje, Chioma; Oshaghi, Mohammad A; Pakpour, Nazzy; Papathanos, Philippos A; Peery, Ashley N; Povelones, Michael; Prakash, Anil; Price, David P; Rajaraman, Ashok; Reimer, Lisa J; Rinker, David C; Rokas, Antonis; Russell, Tanya L; Sagnon, N'Fale; Sharakhova, Maria V; Shea, Terrance; Simão, Felipe A; Simard, Frederic; Slotman, Michel A; Somboon, Pradya; Stegniy, Vladimir; Struchiner, Claudio J; Thomas, Gregg W C; Tojo, Marta; Topalis, Pantelis; Tubio, José M C; Unger, Maria F; Vontas, John; Walton, Catherine; Wilding, Craig S; Willis, Judith H; Wu, Yi-Chieh; Yan, Guiyun; Zdobnov, Evgeny M; Zhou, Xiaofan; Catteruccia, Flaminia; Christophides, George K; Collins, Frank H; Cornman, Robert S; Crisanti, Andrea; Donnelly, Martin J; Emrich, Scott J; Fontaine, Michael C; Gelbart, William; Hahn, Matthew W; Hansen, Immo A; Howell, Paul I; Kafatos, Fotis C; Kellis, Manolis; Lawson, Daniel; Louis, Christos; Luckhart, Shirley; Muskavitch, Marc A T; Ribeiro, José M; Riehle, Michael A; Sharakhov, Igor V; Tu, Zhijian; Zwiebel, Laurence J; Besansky, Nora 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 anopheline mosquito species from diverse locations spanning ~100 million years of evolution. Comparative analyses show faster rates of gene gain and loss, elevated gene shuffling on the X chromosome, and more intron losses, relative to Drosophila. Some determinants of vectorial capacity, such as chemosensory genes, do not show elevated turnover but instead diversify through protein-sequence changes. This dynamism of anopheline genes and genomes may contribute to their flexible capacity to take advantage of new ecological niches, including adapting to humans as primary hosts. PMID:25554792

  20. New protective battle-dress impregnated against mosquito vector bites

    PubMed Central

    2010-01-01

    Background Mixing repellent and organophosphate (OP) insecticides to better control pyrethroid resistant mosquito vectors is a promising strategy developed for bed net impregnation. Here, we investigated the opportunity to adapt this strategy to personal protection in the form of impregnated clothes. Methods We compared standard permethrin impregnated uniforms with uniforms manually impregnated with the repellent KBR3023 alone and in combination with an organophosphate, Pirimiphos-Methyl (PM). Tests were carried out with Aedes aegypti, the dengue fever vector, at dusk in experimental huts. Results Results showed that the personal protection provided by repellent KBR3023-impregnated uniforms is equal to permethrin treated uniforms and that KBR3023/PM-impregnated uniforms are more protective. Conclusion The use of repellents alone or combined with OP on clothes could be promising for personal protection of military troops and travellers if residual activity of the repellents is extended and safety is verified. PMID:20809969

  1. Fighting Arbovirus Transmission: Natural and Engineered Control of Vector Competence in Aedes Mosquitoes

    PubMed Central

    Kean, Joy; Rainey, Stephanie M.; McFarlane, Melanie; Donald, Claire L.; Schnettler, Esther; Kohl, Alain; Pondeville, Emilie

    2015-01-01

    Control of aedine mosquito vectors, either by mosquito population reduction or replacement with refractory mosquitoes, may play an essential role in the fight against arboviral diseases. In this review, we will focus on the development and application of biological approaches, both natural or engineered, to limit mosquito vector competence for arboviruses. The study of mosquito antiviral immunity has led to the identification of a number of host response mechanisms and proteins that are required to control arbovirus replication in mosquitoes, though more factors influencing vector competence are likely to be discovered. We will discuss key aspects of these pathways as targets either for selection of naturally resistant mosquito populations or for mosquito genetic manipulation. Moreover, we will consider the use of endosymbiotic bacteria such as Wolbachia, which in some cases have proven to be remarkably efficient in disrupting arbovirus transmission by mosquitoes, but also the use of naturally occurring insect-specific viruses that may interfere with arboviruses in mosquito vectors. Finally, we will discuss the use of paratransgenesis as well as entomopathogenic fungi, which are also proposed strategies to control vector competence. PMID:26463078

  2. Virus-derived DNA drives mosquito vector tolerance to arboviral infection.

    PubMed

    Goic, Bertsy; Stapleford, Kenneth A; Frangeul, Lionel; Doucet, Aurélien J; Gausson, Valérie; Blanc, Hervé; Schemmel-Jofre, Nidia; Cristofari, Gael; Lambrechts, Louis; Vignuzzi, Marco; Saleh, Maria-Carla

    2016-01-01

    Mosquitoes develop long-lasting viral infections without substantial deleterious effects, despite high viral loads. This makes mosquitoes efficient vectors for emerging viral diseases with enormous burden on public health. How mosquitoes resist and/or tolerate these viruses is poorly understood. Here we show that two species of Aedes mosquitoes infected with two arboviruses from distinct families (dengue or chikungunya) generate a viral-derived DNA (vDNA) that is essential for mosquito survival and viral tolerance. Inhibition of vDNA formation leads to extreme susceptibility to viral infections, reduction of viral small RNAs due to an impaired immune response, and loss of viral tolerance. Our results highlight an essential role of vDNA in viral tolerance that allows mosquito survival and thus may be important for arbovirus dissemination and transmission. Elucidating the mechanisms of mosquito tolerance to arbovirus infection paves the way to conceptualize new antivectorial strategies to selectively eliminate arbovirus-infected mosquitoes. PMID:27580708

  3. Odorant receptor-mediated sperm activation in disease vector mosquitoes

    PubMed Central

    Pitts, R. Jason; Liu, Chao; Zhou, Xiaofan; Malpartida, Juan C.; Zwiebel, Laurence J.

    2014-01-01

    Insects, such as the malaria vector mosquito, Anopheles gambiae, depend upon chemoreceptors to respond to volatiles emitted from a range of environmental sources, most notably blood meal hosts and oviposition sites. A subset of peripheral signaling pathways involved in these insect chemosensory-dependent behaviors requires the activity of heteromeric odorant receptor (OR) ion channel complexes and ligands for numerous A. gambiae ORs (AgOrs) have been identified. Although AgOrs are expressed in nonhead appendages, studies characterizing potential AgOr function in nonolfactory tissues have not been conducted. In the present study, we explore the possibility that AgOrs mediate responses of spermatozoa to endogenous signaling molecules in A. gambiae. In addition to finding AgOr transcript expression in testes, we show that the OR coreceptor, AgOrco, is localized to the flagella of A. gambiae spermatozoa where Orco-specific agonists, antagonists, and other odorant ligands robustly activate flagella beating in an Orco-dependent process. We also demonstrate Orco expression and Orco-mediated activation of spermatozoa in the yellow fever mosquito, Aedes aegypti. Moreover, we find Orco localization in testes across distinct insect taxa and posit that OR-mediated responses in spermatozoa may represent a general characteristic of insect reproduction and an example of convergent evolution. PMID:24550284

  4. Parasite Killing in Malaria Non-Vector Mosquito Anopheles culicifacies Species B: Implication of Nitric Oxide Synthase Upregulation

    PubMed Central

    Vijay, Sonam; Rawat, Manmeet; Adak, Tridibes; Dixit, Rajnikant; Nanda, Nutan; Srivastava, Harish; Sharma, Joginder K.; Prasad, Godavarthi B. K. S.; Sharma, Arun

    2011-01-01

    Background Anopheles culicifacies, the main vector of human malaria in rural India, is a complex of five sibling species. Despite being phylogenetically related, a naturally selected subgroup species B of this sibling species complex is found to be a poor vector of malaria. We have attempted to understand the differences between vector and non-vector Anopheles culicifacies mosquitoes in terms of transcriptionally activated nitric oxide synthase (AcNOS) physiologies to elucidate the mechanism of refractoriness. Identification of the differences between genes and gene products that may impart refractory phenotype can facilitate development of novel malaria transmission blocking strategies. Methodology/Principal Findings We conducted a study on phylogenetically related susceptible (species A) and refractory (species B) sibling species of An. culicifacies mosquitoes to characterize biochemical and molecular differences in AcNOS gene and gene elements and their ability to inhibit oocyst growth. We demonstrate that in species B, AcNOS specific activity and nitrite/nitrates in mid-guts and haemolymph were higher as compared to species A after invasion of the mid-gut by P. vivax at the beginning and during the course of blood feeding. Semiquantitative RT-PCR and real time PCR data of AcNOS concluded that this gene is more abundantly expressed in midgut of species B than in species A and is transcriptionally upregulated post blood meals. Dietary feeding of L-NAME along with blood meals significantly inhibited midgut AcNOS activity leading to an increase in oocyst production in An. culicifacies species B. Conclusions/Significance We hypothesize that upregulation of mosquito innate cytotoxicity due to NOS in refractory strain to Plasmodium vivax infection may contribute to natural refractoriness in An. culicifacies mosquito population. This innate capacity of refractory mosquitoes could represent the ancestral function of the mosquito immune system against the parasite and

  5. MosquitoMap and the Mal-area calculator: new web tools to relate mosquito species distribution with vector borne disease

    PubMed Central

    2010-01-01

    Background Mosquitoes are important vectors of diseases but, in spite of various mosquito faunistic surveys globally, there is a need for a spatial online database of mosquito collection data and distribution summaries. Such a resource could provide entomologists with the results of previous mosquito surveys, and vector disease control workers, preventative medicine practitioners, and health planners with information relating mosquito distribution to vector-borne disease risk. Results A web application called MosquitoMap was constructed comprising mosquito collection point data stored in an ArcGIS 9.3 Server/SQL geodatabase that includes administrative area and vector species x country lookup tables. In addition to the layer containing mosquito collection points, other map layers were made available including environmental, and vector and pathogen/disease distribution layers. An application within MosquitoMap called the Mal-area calculator (MAC) was constructed to quantify the area of overlap, for any area of interest, of vector, human, and disease distribution models. Data standards for mosquito records were developed for MosquitoMap. Conclusion MosquitoMap is a public domain web resource that maps and compares georeferenced mosquito collection points to other spatial information, in a geographical information system setting. The MAC quantifies the Mal-area, i.e. the area where it is theoretically possible for vector-borne disease transmission to occur, thus providing a useful decision tool where other disease information is limited. The Mal-area approach emphasizes the independent but cumulative contribution to disease risk of the vector species predicted present. MosquitoMap adds value to, and makes accessible, the results of past collecting efforts, as well as providing a template for other arthropod spatial databases. PMID:20167090

  6. Monitoring malaria vector control interventions: effectiveness of five different adult mosquito sampling methods.

    PubMed

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

    2013-09-01

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

  7. Screening Mosquito House Entry Points as a Potential Method for Integrated Control of Endophagic Filariasis, Arbovirus and Malaria Vectors

    PubMed Central

    Ogoma, Sheila B.; Lweitoijera, Dickson W.; Ngonyani, Hassan; Furer, Benjamin; Russell, Tanya L.; Mukabana, Wolfgang R.; Killeen, Gerry F.; Moore, Sarah J.

    2010-01-01

    Background Partial mosquito-proofing of houses with screens and ceilings has the potential to reduce indoor densities of malaria mosquitoes. We wish to measure whether it will also reduce indoor densities of vectors of neglected tropical diseases. Methodology The main house entry points preferred by anopheline and culicine vectors were determined through controlled experiments using specially designed experimental huts and village houses in Lupiro village, southern Tanzania. The benefit of screening different entry points (eaves, windows and doors) using PVC-coated fibre glass netting material in terms of reduced indoor densities of mosquitoes was evaluated compared to the control. Findings 23,027 mosquitoes were caught with CDC light traps; 77.9% (17,929) were Anopheles gambiae sensu lato, of which 66.2% were An. arabiensis and 33.8% An. gambiae sensu stricto. The remainder comprised 0.2% (50) An. funestus, 10.2% (2359) Culex spp. and 11.6% (2664) Mansonia spp. Screening eaves reduced densities of Anopheles gambiae s. l. (Relative ratio (RR)  = 0.91; 95% CI = 0.84, 0.98; P = 0.01); Mansonia africana (RR = 0.43; 95% CI = 0.26, 0.76; P<0.001) and Mansonia uniformis (RR = 0.37; 95% CI = 0.25, 0.56; P<0.001) but not Culex quinquefasciatus, Cx. univittatus or Cx. theileri. Numbers of these species were reduced by screening windows and doors but this was not significant. Significance This study confirms that across Africa, screening eaves protects households against important mosquito vectors of filariasis, Rift Valley Fever and O'Nyong nyong as well as malaria. While full house screening is required to exclude Culex species mosquitoes, screening of eaves alone or fitting ceilings has considerable potential for integrated control of other vectors of filariasis, arbovirus and malaria. PMID:20689815

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

    NASA Astrophysics Data System (ADS)

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

    2009-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

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

    PubMed Central

    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. PMID:25609657

  11. Landscape Ecology of Sylvatic Chikungunya Virus and Mosquito Vectors in Southeastern Senegal

    PubMed Central

    Diallo, Diawo; Sall, Amadou A.; Buenemann, Michaela; Chen, Rubing; Faye, Oumar; Diagne, Cheikh T.; Faye, Ousmane; Ba, Yamar; Dia, Ibrahima; Watts, Douglas; Weaver, Scott C.; Hanley, Kathryn A.; Diallo, Mawlouth

    2012-01-01

    The risk of human infection with sylvatic chikungunya (CHIKV) virus was assessed in a focus of sylvatic arbovirus circulation in Senegal by investigating distribution and abundance of anthropophilic Aedes mosquitoes, as well as the abundance and distribution of CHIKV in these mosquitoes. A 1650 km2 area was classified into five land cover classes: forest, barren, savanna, agriculture and village. A total of 39,799 mosquitoes was sampled from all classes using human landing collections between June 2009 and January 2010. Mosquito diversity was extremely high, and overall vector abundance peaked at the start of the rainy season. CHIKV was detected in 42 mosquito pools. Our data suggest that Aedes furcifer, which occurred abundantly in all land cover classes and landed frequently on humans in villages outside of houses, is probably the major bridge vector responsible for the spillover of sylvatic CHIKV to humans. PMID:22720097

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

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

  13. Comparative Genomic Analysis of Drosophila melanogaster and Vector Mosquito Developmental Genes

    PubMed Central

    Behura, Susanta K.; Haugen, Morgan; Flannery, Ellen; Sarro, Joseph; Tessier, Charles R.; Severson, David W.; Duman-Scheel, Molly

    2011-01-01

    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. PMID:21754989

  14. No evidence for local adaptation of dengue viruses to mosquito vector populations in Thailand.

    PubMed

    Fansiri, Thanyalak; Pongsiri, Arissara; Klungthong, Chonticha; Ponlawat, Alongkot; Thaisomboonsuk, Butsaya; Jarman, Richard G; Scott, Thomas W; Lambrechts, Louis

    2016-04-01

    Despite their epidemiological importance, the evolutionary forces that shape the spatial structure of dengue virus genetic diversity are not fully understood. Fine-scale genetic structure of mosquito vector populations and evidence for genotype × genotype interactions between dengue viruses and their mosquito vectors are consistent with the hypothesis that the geographical distribution of dengue virus genetic diversity may reflect viral adaptation to local mosquito populations. To test this hypothesis, we measured vector competence in all sympatric and allopatric combinations of 14 low-passage dengue virus isolates and two wild-type populations of Aedes aegypti mosquitoes sampled in Bangkok and Kamphaeng Phet, two sites located about 300 km apart in Thailand. Despite significant genotype × genotype interactions, we found no evidence for superior vector competence in sympatric versus allopatric vector-virus combinations. Viral phylogenetic analysis revealed no geographical clustering of the 14 isolates, suggesting that high levels of viral migration (gene flow) in Thailand may counteract spatially heterogeneous natural selection. We conclude that it is unlikely that vector-mediated selection is a major driver of dengue virus adaptive evolution at the regional scale that we examined. Dengue virus local adaptation to mosquito vector populations could happen, however, in places or times that we did not test, or at a different geographical scale. PMID:27099625

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

    PubMed Central

    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

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

    PubMed

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

    2016-09-01

    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

  17. Rapid selection against arbovirus-induced apoptosis during infection of a mosquito vector.

    PubMed

    O'Neill, Katelyn; Olson, Bradley J S C; Huang, Ning; Unis, Dave; Clem, Rollie J

    2015-03-10

    Millions of people are infected each year by arboviruses (arthropod-borne viruses) such as chikungunya, dengue, and West Nile viruses, yet for reasons that are largely unknown, only a relatively small number of mosquito species are able to transmit arboviruses. Understanding the complex factors that determine vector competence could facilitate strategies for controlling arbovirus infections. Apoptosis is a potential antiviral defense response that has been shown to be important in other virus-host systems. However, apoptosis is rarely seen in arbovirus-infected mosquito cells, raising questions about its importance as an antiviral defense in mosquitoes. We tested the effect of stimulating apoptosis during arbovirus infection by infecting Aedes aegypti mosquitoes with a Sindbis virus (SINV) clone called MRE/Rpr, in which the MRE-16 strain of SINV was engineered to express the proapoptotic gene reaper from Drosophila. MRE/Rpr exhibited an impaired infection phenotype that included delayed midgut infection, delayed virus replication, and reduced virus accumulation in saliva. Nucleotide sequencing of the reaper insert in virus populations isolated from individual mosquitoes revealed evidence of rapid and strong selection against maintenance of Reaper expression in MRE/Rpr-infected mosquitoes. The impaired phenotype of MRE/Rpr, coupled with the observed negative selection against Reaper expression, indicates that apoptosis is a powerful defense against arbovirus infection in mosquitoes and suggests that arboviruses have evolved mechanisms to avoid stimulating apoptosis in mosquitoes that serve as vectors. PMID:25713358

  18. Mosquito fauna and perspectives for integrated control of urban vector-mosquito populations in Southern Benin (West Africa).

    PubMed

    Lingenfelser, Andre; Rydzanicz, Katarzyna; Kaiser, Achim; Becker, Norbert

    2010-01-01

    This study aims at an integrated vector management (IVM) concept of implementing biological control agents against vector mosquito larvae as a cost-effective and scalable control strategy. In the first step, the mosquito species composition fauna of southern Benin was studied using standard entomological procedures in natural and man-made habitats. Altogether, 24 species belonging to 6 genera of mosquitoes Aedes, Anopheles, Culex, Mansonia, Uranotaenia, Ficalbia were recorded. Five species, Cx. thalassius, Cx. nebulosus, Cx. perfuscus, Cx. pocilipes and Fi. mediolineata are described the first time for Benin. The local mosquito species showed high susceptibility to a Bacillus sphaericus formulation (VectoLex(R) WDG ) in a standardized field test. A dosage of 1 g/m(2) was effective to achieve 100 percent mortality rate for Cx. quinquefasciatus late instar larvae in a sewage habitat, with a residual effect of up to 7 days. After more than 1 year of baseline data collection, operational larviciding with B. thuringiensis var. israelensis and B. sphaericus was commenced in 2006 in selected areas. Microbial insecticides products for larval control show great potential within IVM programmes and may augment control efforts against adult insects, such as the use of insecticide-treated bed nets or indoor wall spraying in many parts of Africa. PMID:20684480

  19. Cloning and analysis of a cecropin gene from the malaria vector mosquito, Anopheles gambiae.

    PubMed

    Vizioli, J; Bulet, P; Charlet, M; Lowenberger, C; Blass, C; Müller, H M; Dimopoulos, G; Hoffmann, J; Kafatos, F C; Richman, A

    2000-02-01

    Parasites of the genus Plasmodium are transmitted to mammalian hosts by anopheline mosquitoes. Within the insect vector, parasite growth and development are potentially limited by antimicrobial defence molecules. Here, we describe the isolation of cDNA and genomic clones encoding a cecropin antibacterial peptide from the malaria vector mosquito Anopheles gambiae. The locus was mapped to polytene division 1C of the X chromosome. Cecropin RNA was induced by infection with bacteria and Plasmodium. RNA levels varied in different body parts of the adult mosquito. During development, cecropin expression was limited to the early pupal stage. The peptide was purified from both adult mosquitoes and cell culture supernatants. Anopheles gambiae synthetic cecropins displayed activity against Gram-negative and Gram-positive bacteria, filamentous fungi and yeasts. PMID:10672074

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed

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

    2013-01-01

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

  2. Pantropic retroviral vectors integrate and express in cells of the malaria mosquito, Anopheles gambiae.

    PubMed Central

    Matsubara, T; Beeman, R W; Shike, H; Besansky, N J; Mukabayire, O; Higgs, S; James, A A; Burns, J C

    1996-01-01

    The lack of efficient mechanisms for stable genetic transformation of medically important insects, such as anopheline mosquitoes, is the single most important impediment to progress in identifying novel control strategies. Currently available techniques for foreign gene expression in insect cells in culture lack the benefit of stable inheritance conferred by integration. To overcome this problem, a new class of pantropic retroviral vectors has been developed in which the amphotropic envelope is completely replaced by the G glycoprotein of vesicular stomatitis virus. The broadened host cell range of these particles allowed successful entry, integration, and expression of heterologous genes in cultured cells of Anopheles gambiae, the principle mosquito vector responsible for the transmission of over 100 million cases of malaria each year. Mosquito cells in culture infected with a pantropic vector expressing hygromycin phosphotransferase from the Drosophila hsp70 promoter were resistant to the antibiotic hygromycin B. Integrated provirus was detected in infected mosquito cell clones grown in selective media. Thus, pantropic retroviral vectors hold promise as a transformation system for mosquitoes in vivo. Images Fig. 2 Fig. 4 Fig. 5 PMID:8650240

  3. Potential transmission of West Nile virus in the British Isles: an ecological review of candidate mosquito bridge vectors.

    PubMed

    Medlock, J M; Snow, K R; Leach, S

    2005-03-01

    West Nile virus (WNV) transmitted by mosquitoes (Diptera: Culicidae) infects various vertebrates, being pathogenic for birds, horses and humans. After its discovery in tropical Africa, sporadic outbreaks of WNV occurred during recent decades in Eurasia, but not the British Isles. WNV reached New York in 1999 and spread to California by 2003, causing widespread outbreaks of West Nile encephalitis across North America, transmitted by many species of mosquitoes, mainly Culex spp. The periodic reappearance of WNV in parts of continental Europe (from southern France to Romania) gives rise to concern over the possibility of WNV invading the British Isles. The British Isles have about 30 endemic mosquito species, several with seasonal abundance and other eco-behavioural characteristics predisposing them to serve as potential WNV bridge vectors from birds to humans. These include: the predominantly ornithophilic Culex pipiens L. and its anthropophilic biotype molestus Forskal; tree-hole adapted Anopheles plumbeus Stephens; saltmarsh-adapted Ochlerotatus caspius Pallas, Oc. detritus Haliday and Oc. dorsalis (Meigen); Coquillettidia richiardii Ficalbi, Culiseta annulata Schrank and Cs. morsitans (Theobald) from vegetated freshwater pools; Aedes cinereus Meigen, Oc. cantans Meigen and Oc. punctor Kirby from seasonal woodland pools. Those underlined have been found carrying WNV in other countries (12 species), including the rarer British species Aedes vexans (Meigen), Culex europaeus Ramos et al., Cx. modestus Ficalbi and Oc. sticticus (Meigen) as well as the Anopheles maculipennis Meigen complex (mainly An. atroparvus van Thiel and An. messeae Falleroni in Britain). Those implicated as key vectors of WNV in Europe are printed bold (four species). So far there is no proof of any arbovirus transmission by mosquitoes in the British Isles, although antibodies to Sindbis, Tahyna, Usutu and West Nile viruses have been detected in British birds. Neighbouring European countries have

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

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

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

  5. Host feeding patterns of established and potential mosquito vectors of West Nile virus in the eastern United States.

    PubMed

    Apperson, Charles S; Hassan, Hassan K; Harrison, Bruce A; Savage, Harry M; Aspen, Stephen E; Farajollahi, Ary; Crans, Wayne; Daniels, Thomas J; Falco, Richard C; Benedict, Mark; Anderson, Michael; McMillen, Larry; Unnasch, Thomas R

    2004-01-01

    An important variable in determining the vectorial capacity of mosquito species for arthropod-borne infections is the degree of contact of the vector and the vertebrate reservoir. This parameter can be estimated by examining the host-feeding habits of vectors. Serological and polymerase chain reaction based methods have been used to study the host-feedings patterns of 21 mosquito species from New York, New Jersey, and Tennessee, 19 of which previously have been found infected with West Nile virus. Mammalophilic mosquito species in New Jersey and New York fed primarily upon white-tailed deer, while those from Memphis, Tennessee, fed mainly upon domestic dogs. A total of 24 different avian host species were detected among the avian-derived blood meals. American Robin, Northern Cardinal, Northern Mockingbird, Tufted Titmouse, and Brown-headed Cowbird were common avian hosts, while blood meals derived from the American Crow were relatively rare. Although the majority of common host species were potentially among the most abundant birds at each location, the proportion of blood meals from the most commonly fed upon avian species was greater than was predicted based upon the likely abundance of these species alone. These findings suggest that vector species for West Nile virus may preferentially feed upon certain avian hosts. PMID:15018775

  6. High-throughput sorting of mosquito larvae for laboratory studies and for future vector control interventions

    PubMed Central

    2012-01-01

    Background Mosquito transgenesis offers new promises for the genetic control of vector-borne infectious diseases such as malaria and dengue fever. Genetic control strategies require the release of large number of male mosquitoes into field populations, whether they are based on the use of sterile males (sterile insect technique, SIT) or on introducing genetic traits conferring refractoriness to disease transmission (population replacement). However, the current absence of high-throughput techniques for sorting different mosquito populations impairs the application of these control measures. Methods A method was developed to generate large mosquito populations of the desired sex and genotype. This method combines flow cytometry and the use of Anopheles gambiae transgenic lines that differentially express fluorescent markers in males and females. Results Fluorescence-assisted sorting allowed single-step isolation of homozygous transgenic mosquitoes from a mixed population. This method was also used to select wild-type males only with high efficiency and accuracy, a highly desirable tool for genetic control strategies where the release of transgenic individuals may be problematic. Importantly, sorted males showed normal mating ability compared to their unsorted brothers. Conclusions The developed method will greatly facilitate both laboratory studies of mosquito vectorial capacity requiring high-throughput approaches and future field interventions in the fight against infectious disease vectors. PMID:22929810

  7. Chitosan/interfering RNA nanoparticle mediated gene silencing in disease vector mosquito larvae

    PubMed Central

    Zhang, Xin; Mysore, Keshava; Flannery, Ellen; Michel, Kristin; Severson, David W.; Zhu, Kun Yan

    2015-01-01

    SHORT ABSTRACT Here we describe a procedure for inhibiting gene function in disease vector mosquitoes through the use of chitosan/interfering RNA nanoparticles that are ingested by larvae. LONG ABSTRACT Vector mosquitoes inflict more human suffering than any other organism—and kill more than one million people each year. The mosquito genome projects facilitated research in new facets of mosquito biology, including functional genetic studies in the primary African malaria vector Anopheles gambiae and the dengue and yellow fever vector Aedes aegypti. RNA interference- (RNAi-) mediated gene silencing has been used to target genes of interest in both of these disease vector mosquito species. Here, we describe a procedure for preparation of chitosan/interfering RNA nanoparticles that are combined with food and ingested by larvae. This technically straightforward, high-throughput, and relatively inexpensive methodology, which is compatible with long double stranded RNA (dsRNA) or small interfering RNA (siRNA) molecules, has been used for the successful knockdown of a number of different genes in A. gambiae and A. aegypti larvae. Following larval feedings, knockdown, which is verified through qRT-PCR or in situ hybridization, can persist at least through the late pupal stage. This methodology may be applicable to a wide variety of mosquito and other insect species, including agricultural pests, as well as other non-model organisms. In addition to its utility in the research laboratory, in the future, chitosan, an inexpensive, non-toxic and biodegradable polymer, could potentially be utilized in the field. PMID:25867635

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

    PubMed Central

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

    2009-01-01

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

  9. Harmonic convergence in the love songs of the dengue vector mosquito.

    PubMed

    Cator, Lauren J; Arthur, Ben J; Harrington, Laura C; Hoy, Ronald R

    2009-02-20

    The familiar buzz of flying mosquitoes is an important mating signal, with the fundamental frequency of the female's flight tone signaling her presence. In the yellow fever and dengue vector Aedes aegypti, both sexes interact acoustically by shifting their flight tones to match, resulting in a courtship duet. Matching is made not at the fundamental frequency of 400 hertz (female) or 600 hertz (male) but at a shared harmonic of 1200 hertz, which exceeds the previously known upper limit of hearing in mosquitoes. Physiological recordings from Johnston's organ (the mosquito's "ear") reveal sensitivity up to 2000 hertz, consistent with our observed courtship behavior. These findings revise widely accepted limits of acoustic behavior in mosquitoes. PMID:19131593

  10. Harmonic convergence in the love songs of the dengue vector mosquito

    PubMed Central

    Cator, Lauren J.; Arthur, Ben J.; Harrington, Laura C.; Hoy, Ronald R.

    2010-01-01

    The familiar buzz of flying mosquitoes is an important mating signal, with the fundamental frequency of the female's flight tone signalling her presence. In the yellow fever and dengue vector, Aedes aegypti, both sexes interact acoustically by shifting their flight tones to match, resulting in a courtship duet. Surprisingly, matching is made not at the fundamental frequency of 400 Hz (female) or 600 Hz (male), but at a shared harmonic of 1200 Hz, which exceeds the previously known upper limit of hearing in mosquitoes. Physiological recordings from Johnston's organ (the mosquito's “ear”) reveal sensitivity up to 2000 Hz, consistent with our observed courtship behavior. These findings revise widely accepted limits of acoustic behavior in mosquitoes. PMID:19131593

  11. The Genome of Anopheles darlingi, the main neotropical malaria vector

    PubMed Central

    Marinotti, Osvaldo; Cerqueira, Gustavo C.; de Almeida, Luiz Gonzaga Paula; Ferro, Maria Inês Tiraboschi; Loreto, Elgion Lucio da Silva; Zaha, Arnaldo; Teixeira, Santuza M. R.; Wespiser, Adam R.; Almeida e Silva, Alexandre; Schlindwein, Aline Daiane; Pacheco, Ana Carolina Landim; da Silva, Artur Luiz da Costa; Graveley, Brenton R.; Walenz, Brian P.; Lima, Bruna de Araujo; Ribeiro, Carlos Alexandre Gomes; Nunes-Silva, Carlos Gustavo; de Carvalho, Carlos Roberto; Soares, Célia Maria de Almeida; de Menezes, Claudia Beatriz Afonso; Matiolli, Cleverson; Caffrey, Daniel; Araújo, Demetrius Antonio M.; de Oliveira, Diana Magalhães; Golenbock, Douglas; Grisard, Edmundo Carlos; Fantinatti-Garboggini, Fabiana; de Carvalho, Fabíola Marques; Barcellos, Fernando Gomes; Prosdocimi, Francisco; May, Gemma; de Azevedo Junior, Gilson Martins; Guimarães, Giselle Moura; Goldman, Gustavo Henrique; Padilha, Itácio Q. M.; Batista, Jacqueline da Silva; Ferro, Jesus Aparecido; Ribeiro, José M. C.; Fietto, Juliana Lopes Rangel; Dabbas, Karina Maia; Cerdeira, Louise; Agnez-Lima, Lucymara Fassarella; Brocchi, Marcelo; de Carvalho, Marcos Oliveira; Teixeira, Marcus de Melo; Diniz Maia, Maria de Mascena; Goldman, Maria Helena S.; Cruz Schneider, Maria Paula; Felipe, Maria Sueli Soares; Hungria, Mariangela; Nicolás, Marisa Fabiana; Pereira, Maristela; Montes, Martín Alejandro; Cantão, Maurício E.; Vincentz, Michel; Rafael, Miriam Silva; Silverman, Neal; Stoco, Patrícia Hermes; Souza, Rangel Celso; Vicentini, Renato; Gazzinelli, Ricardo Tostes; Neves, Rogério de Oliveira; Silva, Rosane; Astolfi-Filho, Spartaco; Maciel, Talles Eduardo Ferreira; Ürményi, Turán P.; Tadei, Wanderli Pedro; Camargo, Erney Plessmann; de Vasconcelos, Ana Tereza Ribeiro

    2013-01-01

    Anopheles darlingi is the principal neotropical malaria vector, responsible for more than a million cases of malaria per year on the American continent. Anopheles darlingi diverged from the African and Asian malaria vectors ∼100 million years ago (mya) and successfully adapted to the New World environment. Here we present an annotated reference A. darlingi genome, sequenced from a wild population of males and females collected in the Brazilian Amazon. A total of 10 481 predicted protein-coding genes were annotated, 72% of which have their closest counterpart in Anopheles gambiae and 21% have highest similarity with other mosquito species. In spite of a long period of divergent evolution, conserved gene synteny was observed between A. darlingi and A. gambiae. More than 10 million single nucleotide polymorphisms and short indels with potential use as genetic markers were identified. Transposable elements correspond to 2.3% of the A. darlingi genome. Genes associated with hematophagy, immunity and insecticide resistance, directly involved in vector–human and vector–parasite interactions, were identified and discussed. This study represents the first effort to sequence the genome of a neotropical malaria vector, and opens a new window through which we can contemplate the evolutionary history of anopheline mosquitoes. It also provides valuable information that may lead to novel strategies to reduce malaria transmission on the South American continent. The A. darlingi genome is accessible at www.labinfo.lncc.br/index.php/anopheles-darlingi. PMID:23761445

  12. Existing Infection Facilitates Establishment and Density of Malaria Parasites in Their Mosquito Vector.

    PubMed

    Pollitt, Laura C; Bram, Joshua T; Blanford, Simon; Jones, Matthew J; Read, Andrew F

    2015-07-01

    Very little is known about how vector-borne pathogens interact within their vector and how this impacts transmission. Here we show that mosquitoes can accumulate mixed strain malaria infections after feeding on multiple hosts. We found that parasites have a greater chance of establishing and reach higher densities if another strain is already present in a mosquito. Mixed infections contained more parasites but these larger populations did not have a detectable impact on vector survival. Together these results suggest that mosquitoes taking multiple infective bites may disproportionally contribute to malaria transmission. This will increase rates of mixed infections in vertebrate hosts, with implications for the evolution of parasite virulence and the spread of drug-resistant strains. Moreover, control measures that reduce parasite prevalence in vertebrate hosts will reduce the likelihood of mosquitoes taking multiple infective feeds, and thus disproportionally reduce transmission. More generally, our study shows that the types of strain interactions detected in vertebrate hosts cannot necessarily be extrapolated to vectors. PMID:26181518

  13. Existing Infection Facilitates Establishment and Density of Malaria Parasites in Their Mosquito Vector

    PubMed Central

    Pollitt, Laura C.; Bram, Joshua T.; Blanford, Simon; Jones, Matthew J.; Read, Andrew F.

    2015-01-01

    Very little is known about how vector-borne pathogens interact within their vector and how this impacts transmission. Here we show that mosquitoes can accumulate mixed strain malaria infections after feeding on multiple hosts. We found that parasites have a greater chance of establishing and reach higher densities if another strain is already present in a mosquito. Mixed infections contained more parasites but these larger populations did not have a detectable impact on vector survival. Together these results suggest that mosquitoes taking multiple infective bites may disproportionally contribute to malaria transmission. This will increase rates of mixed infections in vertebrate hosts, with implications for the evolution of parasite virulence and the spread of drug-resistant strains. Moreover, control measures that reduce parasite prevalence in vertebrate hosts will reduce the likelihood of mosquitoes taking multiple infective feeds, and thus disproportionally reduce transmission. More generally, our study shows that the types of strain interactions detected in vertebrate hosts cannot necessarily be extrapolated to vectors. PMID:26181518

  14. Mosquito vector biology and control in Latin America - A 25th Symposium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 25th Annual Latin American Symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 81st Annual Meeting in New Orleans, LA, in March 2015. The principal objective, for the previous 24 symposia, was to promote participation in the AMCA by vector control spec...

  15. Efficacy of extracts of Bacillus thuringiensis israelensis for the control of mosquito vectors.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than 1 million human cases of Chikungunya were recently reported in India. Aedes aegypti (the yellow fever mosquito) is an important disease vector in India where it transmits Chikungunya, dengue, and yellow fever viruses to humans. In this study, scientists from Bharathiar University in Coim...

  16. Using global information technology to detect, monitor, and control mosquito pest and disease vector populations.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Geographic Information Systems (GIS), image analysis, and remote sensing comprise global information technologies that are used to characterize pest and vector populations of mosquitoes. At this national meeting, scientists from ARS and McNeese State University organized and convened a half-day sym...

  17. Mosquito vector biology and control in Latin America - a 24th symposium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 24th Annual Latin American Symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 80th Annual Meeting in Seattle, WA in February 2014. The principal objective, as for the previous 23 symposia, was to promote participation in the AMCA by vector control spe...

  18. Mosquito Vector Control and Biology in Latin America - A 17th Symposium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 17th Annual Latin America American symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 73rd Annual Meeting in Orlando, FL, in April 2007. The principal objective, as for the previous 16 symposia, was to promote participation in the AMCA by vector cont...

  19. MOSQUITO VECTOR CONTROL AND BIOLOGY IN LATIN AMERICA - A 19TH SYMPOSIUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 19th Annual Latin American symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 75th Annual Meeting in New Orleans, LA, in April 2009. The principal objective, as for the previous 18 symposia, was to promote participation in the AMCA by vector control s...

  20. Field efficacy of four insect repellent products against vector mosquitoes in a tropical environment.

    PubMed

    Yap, H H; Jahangir, K; Zairi, J

    2000-09-01

    Four insect repellent products (RPs) (RP 1, Experimental Repellent Lotion [Bayrepel 12%]; RP 2, Experimental Repellent Cream [Bayrepel 5%]; RP 3, Off! Insect Repellent II Aerosol [deet 15%]; and RP 4, Off! Skintastic II Cream [deet 7.5%]) were evaluated simultaneously for their efficacy against vector and nuisance mosquitoes. The aim of this study was to compare the relative efficacy of RPs based on a new repellent compound, Bayrepel (1-piperidinecarboxylic acid, 2-(2-hydroxyethyl)-1-methylpropylester), with deet (N,N-diethyl-m-toluamide)-based RPs. An 8-h field efficacy of above repellents was evaluated against the day-biting mosquito (Aedes albopictus) and night-biting mosquitoes (Culex quinquefasciatus and Anopheles spp.). Evaluation was carried out by exposing humans with repellent-treated bare limbs to mosquitoes landing and to mosquitoes landing and biting. Repellent product 1 or 2 was applied on the left arm and leg, whereas RP 3 or 4 was applied on the right arm and leg, respectively. Application of these 4 RPs significantly reduced (P < 0.05) the landing and the landing and biting of day-biting and night-biting mosquitoes. All 4 RPs were found to be equally effective (P < 0.05) against Ae. albopictus and Cx. quinquefasciatus. However, for protection against Anopheles spp., RPs 1 and 3 exhibited significantly (P < 0.05) better repellency effect than RPs 2 and 4. PMID:11081653

  1. Hemocytome: deep sequencing analysis of mosquito blood cells in Indian malarial vector Anopheles stephensi.

    PubMed

    Thomas, Tina; De, Tanwee Das; Sharma, Punita; Lata, Suman; Saraswat, Priyanka; Pandey, Kailash C; Dixit, Rajnikant

    2016-07-10

    Hemocytes are tiny circulating blood cells of insects known to play multiple roles in physiological as well as cellular immune responses. However, the molecular nature of hemocytes in blood feeding insects, especially mosquitoes which transmit several deadly diseases such as malaria, dengue etc. is still limited. Therefore, to know the basic molecular composition of naïve mosquito hemocyte encoded proteins, we sequenced RNA-Seq library and analyzed a total of 13,105,858 Illumina sequencing reads in the mosquito Anopheles stephensi, an urban malarial vector in India. Denovo assembly approach yielded a buildup of 3025 contigs, for molecular and functional annotation. A total of 1829 contigs (48%) could be mapped to the mosquito transcript database, while out of remaining 1196 unmatched contigs, at least 1108 contigs i.e. 40% of total contigs, yielded a significant match to the available draft genome. ImmunoDB analysis predicted a total of 88 putative hemocyte transcripts belonging to 11 immune family proteins. A comprehensive molecular analysis of several unique transcripts including novel LRR, Holotricin, OBP, NiFU, that are involved in immunity, chemo sensing, cell-cell communication, nitrogen fixation/metabolism etc. provides initial evidence that mosquito hemocytes carry unique ability to meet and manage cell specific diverse functions of the mosquito blood. An unexpected observation of abundant transcripts encoding hypothetical proteins with unknown functions indicated that a much of the hemocyte biology remains to be understood. PMID:26915489

  2. Hybridization in situ of Salivary Glands, Ovaries, and Embryos of Vector Mosquitoes

    PubMed Central

    Juhn, Jennifer; James, Anthony A.

    2012-01-01

    Mosquitoes are vectors for a diverse set of pathogens including arboviruses, protozoan parasites and nematodes. Investigation of transcripts and gene regulators that are expressed in tissues in which the mosquito host and pathogen interact, and in organs involved in reproduction are of great interest for strategies to reduce mosquito-borne disease transmission and disrupt egg development. A number of tools have been employed to study and validate the temporal and tissue-specific regulation of gene expression. Here, we describe protocols that have been developed to obtain spatial information, which enhances our understanding of where specific genes are expressed and their products accumulate. The protocol described has been used to validate expression and determine accumulation patterns of transcripts in tissues related to mosquito-borne pathogen transmission, such as female salivary glands, as well as subcellular compartments of ovaries and embryos, which relate to mosquito reproduction and development. The following procedures represent an optimized methodology that improves the efficiency of various steps in the protocol without loss of target-specific hybridization signals. Guidelines for RNA probe preparation, dissection of soft tissues and the general procedure for fixation and hybridization are described in Part A, while steps specific for the collection, fixation, pre-hybridization and hybridization of mosquito embryos are detailed in Part B. PMID:22781778

  3. Phylogenetic analyses of vector mosquito basic helix-loop-helix transcription factors.

    PubMed

    Zhang, D B; Wang, Y; Liu, A K; Wang, X H; Dang, C W; Yao, Q; Chen, K P

    2013-10-01

    Basic helix-loop-helix (bHLH) transcription factors play critical roles in the regulation of a wide range of developmental processes in higher organisms and have been identified in more than 20 organisms. Mosquitoes are important vectors of certain human diseases. In this study, Aedes aegypti, Anopheles gambiae str. PEST and Culex quinquefasciatus genomes were found to encode 55, 55 and 57 bHLH genes, respectively. Further phylogenetic analyses and OrthoDB and Kyoto encyclopedia of genes and genomes orthology database searches led us to define orthology for all the identified mosquito bHLHs successfully. This provides useful information with which to update annotations to 40 Ae. aegypti, 55 An. gambiae and 38 C. quinquefasciatus bHLH genes in VectorBase. The mosquito lineage has more bHLH genes in the Atonal, neurogenin (Ngn) and Hes-related with YRPW motif (Hey) families than do other insect species, suggesting that mosquitoes have evolved to be more sensitive to vibration, light and chemicals. Mosquito bHLH genes generally have higher evolutionary rates than other insect species. However, no pervasive positive selection occurred in the evolution of insect bHLH genes. Only episodic positive selection was found to affect evolution of bHLH genes in 11 families. Besides, coding regions of several Ae. aegypti bHLH motifs have unusually long introns in which multiple copies of transposable elements have been identified. These data provide a solid basis for further studies on structures and functions of bHLH proteins in the regulation of mosquito development and for prevention and control of mosquito-mediated human diseases. PMID:23906262

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

    PubMed

    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. PMID:26470453

  5. Mosquito larvicidal properties of aqueous and acetone extracts of Trianthema portulacastrum Linn. (family: Aizoaceae) against vector species of mosquitoes.

    PubMed

    Singh, S P; Raghavendra, K; Thomas, T G

    2011-12-01

    Crude aqueous and acetone extracts of leaf of Trianthema portulacastrum was evaluated for its mosquito larvicidal properties against the larvae of four vector species of mosquito under laboratory conditions. These extracts showed good larvicidal properties, 100% mortality in the third instar larvae was observed in the larval bioassay test with Anopheles culicifacies, Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti at a concentration of 1.0, 0.75, 0.75 and 1.0% respectively. The LD50 values estimated for aqueous extract against the larvae of An. culicifacies, An. stephensi, Cx. quinquefasciatus and Ae. aegypti were 0.17, 0.15, 0.18 and 0.17% and LD90 values were 0.57, 0.58, 0.76, and 0.75% respectively. The LD50 values estimated for acetone extract against the larvae of An. culicifacies, An. stephensi, Cx. quinquefasciatus and Ae. aegypti were 0.09, 0.10, 0.09 and 0.12 % and LD90 values were 0.28, 0.25, 0.26 and 0.26% respectively. It is observed that the acetone extract is more effective as compared to aqueous extract. Trianthema portulacastrum can be considered as a probable source of photochemical used for the development of larvicide against disease vectors. PMID:23781639

  6. Antennal-expressed ammonium transporters in the malaria vector mosquito Anopheles gambiae.

    PubMed

    Pitts, R Jason; Derryberry, Stephen L; Pulous, Fadi E; Zwiebel, Laurence J

    2014-01-01

    The principal Afrotropical malaria vector mosquito, Anopheles gambiae remains a significant threat to human health. In this anthropophagic species, females detect and respond to a range of human-derived volatile kairomones such as ammonia, lactic acid, and other carboxylic acids in their quest for blood meals. While the molecular underpinnings of mosquito olfaction and host seeking are becoming better understood, many questions remain unanswered. In this study, we have identified and characterized two candidate ammonium transporter genes, AgAmt and AgRh50 that are expressed in the mosquito antenna and may contribute to physiological and behavioral responses to ammonia, which is an important host kairomone for vector mosquitoes. AgAmt transcripts are highly enhanced in female antennae while a splice variant of AgRh50 appears to be antennal-specific. Functional expression of AgAmt in Xenopus laevis oocytes facilitates inward currents in response to both ammonium and methylammonium, while AgRh50 is able to partially complement a yeast ammonium transporter mutant strain, validating their conserved roles as ammonium transporters. We present evidence to suggest that both AgAmt and AgRh50 are in vivo ammonium transporters that are important for ammonia sensitivity in An. gambiae antennae, either by clearing ammonia from the sensillar lymph or by facilitating sensory neuron responses to environmental exposure. Accordingly, AgAmt and AgRh50 represent new and potentially important targets for the development of novel vector control strategies. PMID:25360676

  7. Cytochrome B Analysis of Mosquito Blood Meals: Identifying Wildlife Hosts of West Nile Virus Mosquito Vectors in Wyoming, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Female mosquitoes commonly exhibit patterns of blood feeding from vertebrate hosts, a behavior that strongly influences mosquito pathogen infection and transmission. The vertebrate host dynamics of the mosquito transmitted arbovirus, West Nile virus (family Flaviviridae, genus Flavivirus, WNV) in sa...

  8. Development of non-defective recombinant densovirus vectors for microRNA delivery in the invasive vector mosquito, Aedes albopictus

    PubMed Central

    Liu, Peiwen; Li, Xiaocong; Gu, Jinbao; Dong, Yunqiao; Liu, Yan; Santhosh, Puthiyakunnon; Chen, Xiaoguang

    2016-01-01

    We previously reported that mosquito densoviruses (MDVs) are potential vectors for delivering foreign nucleic acids into mosquito cells. However, considering existing expression strategies, recombinant viruses would inevitably become replication-defective viruses and lose their ability for secondary transmission. The packaging limitations of the virion represent a barrier for the development of MDVs for viral paratransgenesis or as high-efficiency bioinsecticides. Herein, we report the development of a non-defective recombinant Aedes aegypti densovirus (AaeDV) miRNA expression system, mediated by an artificial intron, using an intronic miRNA expression strategy. We demonstrated that this recombinant vector could be used to overexpress endogenous miRNAs or to decrease endogenous miRNAs by generating antisense sponges to explore the biological functions of miRNAs. In addition, the vector could express antisense-miRNAs to induce efficient gene silencing in vivo and in vitro. The recombinant virus effectively self-replicated and retained its secondary transmission ability, similar to the wild-type virus. The recombinant virus was also genetically stable. This study demonstrated the first construction of a non-defective recombinant MDV miRNA expression system, which represents a tool for the functional analysis of mosquito genes and lays the foundation for the application of viral paratransgenesis for dengue virus control. PMID:26879823

  9. Detection of Invasive Mosquito Vectors Using Environmental DNA (eDNA) from Water Samples.

    PubMed

    Schneider, Judith; Valentini, Alice; Dejean, Tony; Montarsi, Fabrizio; Taberlet, Pierre; Glaizot, Olivier; Fumagalli, Luca

    2016-01-01

    Repeated introductions and spread of invasive mosquito species (IMS) have been recorded on a large scale these last decades worldwide. In this context, members of the mosquito genus Aedes can present serious risks to public health as they have or may develop vector competence for various viral diseases. While the Tiger mosquito (Aedes albopictus) is a well-known vector for e.g. dengue and chikungunya viruses, the Asian bush mosquito (Ae. j. japonicus) and Ae. koreicus have shown vector competence in the field and the laboratory for a number of viruses including dengue, West Nile fever and Japanese encephalitis. Early detection and identification is therefore crucial for successful eradication or control strategies. Traditional specific identification and monitoring of different and/or cryptic life stages of the invasive Aedes species based on morphological grounds may lead to misidentifications, and are problematic when extensive surveillance is needed. In this study, we developed, tested and applied an environmental DNA (eDNA) approach for the detection of three IMS, based on water samples collected in the field in several European countries. We compared real-time quantitative PCR (qPCR) assays specific for these three species and an eDNA metabarcoding approach with traditional sampling, and discussed the advantages and limitations of these methods. Detection probabilities for eDNA-based approaches were in most of the specific comparisons higher than for traditional survey and the results were congruent between both molecular methods, confirming the reliability and efficiency of alternative eDNA-based techniques for the early and unambiguous detection and surveillance of invasive mosquito vectors. The ease of water sampling procedures in the eDNA approach tested here allows the development of large-scale monitoring and surveillance programs of IMS, especially using citizen science projects. PMID:27626642

  10. Evolutionary Dynamics of Immune-Related Genes and Pathways in Disease-Vector Mosquitoes

    PubMed Central

    Waterhouse, Robert M.; Kriventseva, Evgenia V.; Meister, Stephan; Xi, Zhiyong; Alvarez, Kanwal S.; Bartholomay, Lyric C.; Barillas-Mury, Carolina; Bian, Guowu; Blandin, Stephanie; Christensen, Bruce M.; Dong, Yuemei; Jiang, Haobo; Kanost, Michael R.; Koutsos, Anastasios C.; Levashina, Elena A.; Li, Jianyong; Ligoxygakis, Petros; MacCallum, Robert M.; Mayhew, George F.; Mendes, Antonio; Michel, Kristin; Osta, Mike A.; Paskewitz, Susan; Shin, Sang Woon; Vlachou, Dina; Wang, Lihui; Wei, Weiqi; Zheng, Liangbiao; Zou, Zhen; Severson, David W.; Raikhel, Alexander S.; Kafatos, Fotis C.; Dimopoulos, George; Zdobnov, Evgeny M.; Christophides, George K.

    2007-01-01

    Mosquitoes are vectors of parasitic and viral diseases of immense importance for public health. The acquisition of the genome sequence of the yellow fever and Dengue vector, Aedes aegypti (Aa), has enabled a comparative phylogenomic analysis of the insect immune repertoire: in Aa, the malaria vector Anopheles gambiae (Ag), and the fruit fly Drosophila melanogaster (Dm). Analysis of immune signaling pathways and response modules reveals both conservative and rapidly evolving features associated with different functional gene categories and particular aspects of immune reactions. These dynamics reflect in part continuous readjustment between accommodation and rejection of pathogens and suggest how innate immunity may have evolved. PMID:17588928

  11. Evolutionary dynamics of immune-related genes and pathways in disease-vector mosquitoes.

    PubMed

    Waterhouse, Robert M; Kriventseva, Evgenia V; Meister, Stephan; Xi, Zhiyong; Alvarez, Kanwal S; Bartholomay, Lyric C; Barillas-Mury, Carolina; Bian, Guowu; Blandin, Stephanie; Christensen, Bruce M; Dong, Yuemei; Jiang, Haobo; Kanost, Michael R; Koutsos, Anastasios C; Levashina, Elena A; Li, Jianyong; Ligoxygakis, Petros; Maccallum, Robert M; Mayhew, George F; Mendes, Antonio; Michel, Kristin; Osta, Mike A; Paskewitz, Susan; Shin, Sang Woon; Vlachou, Dina; Wang, Lihui; Wei, Weiqi; Zheng, Liangbiao; Zou, Zhen; Severson, David W; Raikhel, Alexander S; Kafatos, Fotis C; Dimopoulos, George; Zdobnov, Evgeny M; Christophides, George K

    2007-06-22

    Mosquitoes are vectors of parasitic and viral diseases of immense importance for public health. The acquisition of the genome sequence of the yellow fever and Dengue vector, Aedes aegypti (Aa), has enabled a comparative phylogenomic analysis of the insect immune repertoire: in Aa, the malaria vector Anopheles gambiae (Ag), and the fruit fly Drosophila melanogaster (Dm). Analysis of immune signaling pathways and response modules reveals both conservative and rapidly evolving features associated with different functional gene categories and particular aspects of immune reactions. These dynamics reflect in part continuous readjustment between accommodation and rejection of pathogens and suggest how innate immunity may have evolved. PMID:17588928

  12. Mosquitoes and transmission of malaria parasites – not just vectors

    PubMed Central

    Paul, Richard EL; Diallo, Mawlouth; Brey, Paul T

    2004-01-01

    The regional malaria epidemics of the early 1900s provided the basis for much of our current understanding of malaria epidemiology. Colonel Gill, an eminent malariologist of that time, suggested that the explosive nature of the regional epidemics was due to a sudden increased infectiousness of the adult population. His pertinent observations underlying this suggestion have, however, gone unheeded. Here, the literature on Plasmodium seasonal behaviour is reviewed and three historical data sets, concerning seasonal transmission of Plasmodium falciparum, are examined. It is proposed that the dramatic seasonal increase in the density of uninfected mosquito bites results in an increased infectiousness of the human reservoir of infection and, therefore, plays a key role in "kick-starting" malaria parasite transmission. PMID:15533243

  13. Ecology and control of dengue vector mosquitoes in Taiwan.

    PubMed

    Chen, Y R; Hwang, J S; Guo, Y J

    1994-12-01

    Due to rapid urbanization, industrialization and social changes in recent years, the use of packing materials and tires has dramatically increased in the Taiwan area. What is more is that some parts of southern Taiwan are short of water resources and water preservation with huge containers becomes part of custom in those areas. Storage water containers, waste vessels and tires are good habitats for Aedes. Meanwhile, some persons traveling to dengue endemic countries bring the dengue disease back to Taiwan. Surveys taken since 1988 show that dengue occurs mainly in the urban and coastal areas where Aedes aegypti is prevalent. This species is the most important, if not the only, vector of dengue in Taiwan. It appears that the types of Aedes breeding have changed quickly. In dengue fever epidemic areas, the most popular breeding sites are ornamental containers (38.8%), storage water containers (30.1%), discarded containers (25.4%), receptacles (3.3%) and water collection in the basement (2.2%). In dengue fever epidemic areas, those building basements, huge water containers, waste vessels and waste tires in open fields are most difficult to clean up and manage and become the most popular Aedes habitats. We established a waste recycling system and promoted a breeding site reduction campaign for waste management, including the application of Temephos in containers to kill larvae. For the drinking water management, fish were released in water containers to prevent larval breeding. It should be mentioned that with the integrated pest control and regular inspections of Aedes larvae in Taiwan the density figures 1, 2-5, and 6 or above for Aedes aegypti were 38.7%, 42.9%, and 18.4%, respectively, in 1988, and in 1993 were 90.8%, 9.2% and 0%. The incidence of dengue fever cases has 98% decreased since 1988. In 1990 and 1993, there was no indigenous cases. We have concluded that integrated pest control is the best and most effective method for dengue fever control, including

  14. Abundance of West Nile virus mosquito vectors in relation to climate and landscape variables.

    PubMed

    Deichmeister, Jayne M; Telang, Aparna

    2011-06-01

    It is currently unclear if the potential for West Nile virus transmission by mosquito vectors in the eastern United States is related to landscape or climate factors or both. We compared abundance of vector species between urban and suburban neighborhoods of Henrico County, VA, in relation to the following factors: temperature, precipitation, canopy cover, building footprint, and proximity to drainage infrastructure. Mosquitoes were collected throughout the 2005, 2006, and 2007 seasons and tested for West Nile virus (WNV) in pools of 10-50. Test results of mosquito pools were compared to average site abundance from 37 sites in Henrico County, VA; abundance was then examined in relation to ecological variables. Urban infrastructure was positively correlated with the abundance of Culex pipiens L./Cx. restuans, and our findings implicate combined sewer overflow systems as large contributors to Culex vector populations. No measure of urbanization examined in our study was correlated with Aedes albopictus abundance. Our study showed that certain landscape variables identified using Geographic Information Systems are valuable for predicting primary WNV vector abundance in Virginia, and that temperature along with low precipitation are strong predictors of population growth. Our results support other regional studies that found WNV proliferates under drought conditions. PMID:21635644

  15. Coquillettidia (Culicidae, Diptera) mosquitoes are natural vectors of avian malaria in Africa

    PubMed Central

    2009-01-01

    Background The mosquito vectors of Plasmodium spp. have largely been overlooked in studies of ecology and evolution of avian malaria and other vertebrates in wildlife. Methods Plasmodium DNA from wild-caught Coquillettidia spp. collected from lowland forests in Cameroon was isolated and sequenced using nested PCR. Female Coquillettidia aurites were also dissected and salivary glands were isolated and microscopically examined for the presence of sporozoites. Results In total, 33% (85/256) of mosquito pools tested positive for avian Plasmodium spp., harbouring at least eight distinct parasite lineages. Sporozoites of Plasmodium spp. were recorded in salivary glands of C. aurites supporting the PCR data that the parasites complete development in these mosquitoes. Results suggest C. aurites, Coquillettidia pseudoconopas and Coquillettidia metallica as new and important vectors of avian malaria in Africa. All parasite lineages recovered clustered with parasites formerly identified from several bird species and suggest the vectors capability of infecting birds from different families. Conclusion Identifying the major vectors of avian Plasmodium spp. will assist in understanding the epizootiology of avian malaria, including differences in this disease distribution between pristine and disturbed landscapes. PMID:19664282

  16. Comparative responses of mosquito vectors of West Nile virus to light traps augmented with chemical attractant and to human hosts.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Scientists in the USA seek to develop Global Information Technology (GIS, GPS, remote sensing)-based systems that can be used to deploy sentinel traps for mosquito vectors and for the implementation and evaluation of mosquito control. Achieving this objective requires the development of methods for...

  17. Sheep Skin Odor Improves Trap Captures of Mosquito Vectors of Rift Valley Fever

    PubMed Central

    Tchouassi, David P.; Sang, Rosemary; Sole, Catherine L.; Bastos, Armanda D. S.; Mithoefer, Klaus; Torto, Baldwyn

    2012-01-01

    In recent years, the East African region has seen an increase in arboviral diseases transmitted by blood-feeding arthropods. Effective surveillance to monitor and reduce incidence of these infections requires the use of appropriate vector sampling tools. Here, trapped skin volatiles on fur from sheep, a known preferred host of mosquito vectors of Rift Valley fever virus (RVFV), were used with a standard CDC light trap to improve catches of mosquito vectors. We tested the standard CDC light trap alone (L), and baited with (a) CO2 (LC), (b) animal volatiles (LF), and (c) CO2 plus animal volatiles (LCF) in two highly endemic areas for RVF in Kenya (Marigat and Ijara districts) from March–June and September–December 2010. The incidence rate ratios (IRR) that mosquito species chose traps baited with treatments (LCF, LC and LF) instead of the control (L) were estimated. Marigat was dominated by secondary vectors and host-seeking mosquitoes were 3–4 times more likely to enter LC and LCF traps [IRR = 3.1 and IRR = 3.8 respectively] than the L only trap. The LCF trap captured a greater number of mosquitoes than the LC trap (IRR = 1.23) although the difference was not significant. Analogous results were observed at Ijara, where species were dominated by key primary and primary RVFV vectors, with 1.6-, 6.5-, and 8.5-fold increases in trap captures recorded in LF, LC and LCF baited traps respectively, relative to the control. These catches all differed significantly from those trapped in L only. Further, there was a significant increase in trap captures in LCF compared to LC (IRR = 1.63). Mosquito species composition and trap counts differed between the RVF sites. However, within each site, catches differed in abundance only and no species preferences were noted in the different baited-traps. Identifying the attractive components present in these natural odors should lead to development of an effective odor-bait trapping system for population density

  18. Determining the spatial autocorrelation of dengue vector populations: influences of mosquito sampling method, covariables, and vector control.

    PubMed

    Azil, Aishah H; Bruce, David; Williams, Craig R

    2014-06-01

    We investigated spatial autocorrelation of female Aedes aegypti L. mosquito abundance from BG-Sentinel trap and sticky ovitrap collections in Cairns, north Queensland, Australia. BG-Sentinel trap collections in 2010 show a significant spatial autocorrelation across the study site and over a smaller spatial extent, while sticky ovitrap collections only indicate a non-significant, weak spatial autocorrelation. The BG-Sentinel trap collections were suitable for spatial interpolation using ordinary kriging and cokriging techniques. The uses of Premise Condition Index and potential breeding container data have helped improve our prediction of vector abundance. Semiovariograms and prediction maps indicate that the spatial autocorrelation of mosquito abundance determined by BG-Sentinel traps extends farther compared to sticky ovitrap collections. Based on our data, fewer BG-Sentinel traps are required to represent vector abundance at a series of houses compared to sticky ovitraps. A lack of spatial structure was observed following vector control treatment in the area. This finding has implications for the design and costs of dengue vector surveillance programs. PMID:24820568

  19. Mosquito Vector Biology and Control in Latin America-A 25TH Symposium.

    PubMed

    2015-09-01

    The 25th Annual Latin American Symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 81st Annual Meeting in New Orleans, LA, in March 2015. The principal objective, as for the previous 24 symposia, was to promote participation in the AMCA by vector control specialists, public health workers, and academicians from Latin America. This publication includes summaries of 24 presentations that were given orally in Spanish by participants from Colombia, Mexico, and the USA. Topics addressed in the symposium included: surveillance, operations, ecology, chemical control, studies of dengue viruses, and insecticide resistance. Insect vectors included Aedes, Culex, and Anopheles mosquitoes in addition to phlebotomine sand flies and triatomine bugs. PMID:26375913

  20. Simplified Models of Vector Control Impact upon Malaria Transmission by Zoophagic Mosquitoes

    PubMed Central

    Kiware, Samson S.; Chitnis, Nakul; Moore, Sarah J.; Devine, Gregor J.; Majambere, Silas; Merrill, Stephen; Killeen, Gerry F.

    2012-01-01

    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

  1. Turning cigarette butt waste into an alternative control tool against an insecticide-resistant mosquito vector.

    PubMed

    Dieng, Hamady; Rajasaygar, Sudha; Ahmad, Abu Hassan; Ahmad, Hamdan; Rawi, Che Salmah Md; Zuharah, Wan Fatma; Satho, Tomomitsu; Miake, Fumio; Fukumitsu, Yuki; Saad, Ahmad Ramli; Ghani, Idris Abd; Vargas, Ronald Enrique Morales; Majid, Abdul Hafiz Ab; Abubakar, Sazaly

    2013-12-01

    Annually, 4.5 trillion cigarette butts (CBs) are flicked into our environment. Evidence exists that CB waste is deadly to aquatic life, but their lethality to the aquatic life of the main dengue vector is unknown. CBs are full of toxicants that occur naturally, during planting and manufacturing, which may act as larvicidal agents. We assessed Aedes aegypti vulnerability to Marlboro butts during its development. Overall, CBs showed insecticidal activities against larvae. At early phases of development, mortality rates were much higher in two CBs solution (2CBSol) and 3CBSol microcosms (MICRs). Larval survival gradually decreased with development in 1CBSol-MICRs. However, in great presence of CBs, mortality was high even for the late developmental stages. These results suggest that A. aegypti larvae are vulnerable to CB presence in their habitats, but this effect was seen most during the early developmental phases and in the presence of increased amounts of cigarette remnants. CB filters are being used as raw material in many sectors, i.e., brick, art, fashion, plastic industries, as a practical solution to the pollution problem, the observed butt waste toxicity to mosquito larvae open new avenues for the identification of novel insecticide products. PMID:23999373

  2. Occurrence of a mosquito vector in bird houses: Developmental consequences and potential epidemiological implications.

    PubMed

    Dieng, Hamady; Hassan, Rahimah Binti; Hassan, Ahmad Abu; Ghani, Idris Abd; Abang, Fatimah Bt; Satho, Tomomitsu; Miake, Fumio; Ahmad, Hamdan; Fukumitsu, Yuki; Hashim, Nur Aida; Zuharah, Wan Fatma; Kassim, Nur Faeza Abu; Majid, Abdul Hafiz Ab; Selvarajoo, Rekha; Nolasco-Hipolito, Cirilo; Ajibola, Olaide Olawunmi; Tuen, Andrew Alek

    2015-05-01

    Even with continuous vector control, dengue is still a growing threat to public health in Southeast Asia. Main causes comprise difficulties in identifying productive breeding sites and inappropriate targeted chemical interventions. In this region, rural families keep live birds in backyards and dengue mosquitoes have been reported in containers in the cages. To focus on this particular breeding site, we examined the capacity of bird fecal matter (BFM) from the spotted dove, to support Aedes albopictus larval growth. The impact of BFM larval uptake on some adult fitness traits influencing vectorial capacity was also investigated. In serial bioassays involving a high and low larval density (HD and LD), BFM and larval standard food (LSF) affected differently larval development. At HD, development was longer in the BFM environment. There were no appreciable mortality differences between the two treatments, which resulted in similar pupation and adult emergence successes. BFM treatment produced a better gender balance. There were comparable levels of blood uptake and egg production in BFM and LSF females at LD; that was not the case for the HD one, which resulted in bigger adults. BFM and LSF females displayed equivalent lifespans; in males, this parameter was shorter in those derived from the BFM/LD treatment. Taken together these results suggest that bird defecations successfully support the development of Ae. albopictus. Due to their cryptic aspects, containers used to supply water to encaged birds may not have been targeted by chemical interventions. PMID:25617636

  3. Mosquitoes as Potential Bridge Vectors of Malaria Parasites from Non-Human Primates to Humans

    PubMed Central

    Verhulst, Niels O.; Smallegange, Renate C.; Takken, Willem

    2012-01-01

    Malaria is caused by Plasmodium parasites which are transmitted by mosquitoes. Until recently, human malaria was considered to be caused by human-specific Plasmodium species. Studies on Plasmodium parasites in non-human primates (NHPs), however, have identified parasite species in gorillas and chimpanzees that are closely related to human Plasmodium species. Moreover, P. knowlesi, long known as a parasite of monkeys, frequently infects humans. The requirements for such a cross-species exchange and especially the role of mosquitoes in this process are discussed, as the latter may act as bridge vectors of Plasmodium species between different primates. Little is known about the mosquito species that would bite both humans and NHPs and if so, whether humans and NHPs share the same Plasmodium vectors. To understand the vector-host interactions that can lead to an increased Plasmodium transmission between species, studies are required that reveal the nature of these interactions. Studying the potential role of NHPs as a Plasmodium reservoir for humans will contribute to the ongoing efforts of human malaria elimination, and will help to focus on critical areas that should be considered in achieving this goal. PMID:22701434

  4. West Nile Virus Vector Competency of Culex quinquefasciatus Mosquitoes in the Galápagos Islands

    PubMed Central

    Eastwood, Gillian; Kramer, Laura D.; Goodman, Simon J.; Cunningham, Andrew A.

    2011-01-01

    The mosquito-transmitted pathogen West Nile virus (WNV) is not yet present in the Galápagos Archipelago of Ecuador. However, concern exists for fragile endemic island fauna after population decreases in several North American bird species and pathology in certain reptiles. We examined WNV vector competency of a Galápagos strain of mosquito (Culex quinquefasciatus Say). Field specimens were tested for their capacity to transmit the WN02-1956 strain of WNV after incubation at 27°C or 30°C. Rates of infection, dissemination, and transmission all increased with days post-exposure to WNV, and the highest rates were observed at 28 days. Infection rates peaked at 59% and transmission rates peaked at 44% (of mosquitoes tested). Vector efficiency increased after day 14. Rates of infection but not of transmission were significantly influence by temperature. No vertical transmission was detectable. We demonstrate that Galápagos Cx. quinquefasciatus are competent WNV vectors, and therefore should be considered an animal and public health risk for the islands and controlled wherever possible. PMID:21896799

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

    PubMed Central

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

    2011-01-01

    Background & objectives: 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). Methods: 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/cm2 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. Results: Complete (100%) protection was achieved at 10 mg/cm2 cream formulation of Advanced Odomos (1.2 mg a.i/cm2) dose against An. stephensi and 12 mg/cm2 (1.44 mg a.i./cm2) against Ae. aegypti on human baits. There was no statistically significant differences in per cent protection against mosquito bites between Advanced o0 domos 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. Interpretation & conclusions: Advanced odomos cream applied at 10 mg/cm2 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/cm2 will be appropriate and in case of Ae. aegypti more than 10 mg/cm2 application is required for complete protection. In conclusion, the Advanced

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

    NASA Astrophysics Data System (ADS)

    Morin, Cory W.; Comrie, Andrew C.

    2010-09-01

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

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

    PubMed

    Morin, Cory W; Comrie, Andrew C

    2010-09-01

    Climate can strongly influence the population dynamics of disease vectors and is consequently a key component of disease ecology. Future climate change and variability may alter the location and seasonality of many disease vectors, possibly increasing the risk of disease transmission to humans. The mosquito species Culex quinquefasciatus is a concern across the southern United States because of its role as a West Nile virus vector and its affinity for urban environments. Using established relationships between atmospheric variables (temperature and precipitation) and mosquito development, we have created the Dynamic Mosquito Simulation Model (DyMSiM) to simulate Cx. quinquefasciatus population dynamics. The model is driven with climate data and validated against mosquito count data from Pasco County, Florida and Coachella Valley, California. Using 1-week and 2-week filters, mosquito trap data are reproduced well by the model (P < 0.0001). Dry environments in southern California produce different mosquito population trends than moist locations in Florida. Florida and California mosquito populations are generally temperature-limited in winter. In California, locations are water-limited through much of the year. Using future climate projection data generated by the National Center for Atmospheric Research CCSM3 general circulation model, we applied temperature and precipitation offsets to the climate data at each location to evaluate mosquito population sensitivity to possible future climate conditions. We found that temperature and precipitation shifts act interdependently to cause remarkable changes in modeled mosquito population dynamics. Impacts include a summer population decline from drying in California due to loss of immature mosquito habitats, and in Florida a decrease in late-season mosquito populations due to drier late summer conditions. PMID:20683620

  8. The Developmental Transcriptome of the Mosquito Aedes aegypti, an Invasive Species and Major Arbovirus Vector

    PubMed Central

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

    2013-01-01

    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) PMID:23833213

  9. A novel biopesticide PONNEEM to control human vector mosquitoes Anopheles stephensi L. and Culex quinquefasciatus Say.

    PubMed

    Maheswaran, Rajan; Ignacimuthu, Savarimuthu

    2015-09-01

    Organophosphate pesticides are widely used in vector mosquito management and agricultural pest management. These chemicals enter into natural water bodies and soil and cause hazards to the environment. The objective of this study was to prepare a natural pesticide which will not harm the environment and yet control vector mosquitoes. PONNEEM, a novel biopesticide, patented and prepared from the oils of Azadirachta indica and Pongamia glabra, was tested against Anopheles stephensi and Culex quinquefasciatus. One hundred percent larvicidal and ovicidal activities were observed at 0.1-ppm concentration of PONNEEM against the two mosquito species under laboratory and sunlight conditions up to 12 months from the date of manufacture. Very high oviposition reduction of 26.46 and 32.16 % is also recorded. Reductions in α-esterase level (0.0818 ± 0.340 and 0.2188 ± 0.003), β-esterase level (0.0866 ± 0.026 and 0.0398 ± 0.010 μg naphthol produced/min/mg larval protein), glutathione S-transferase enzyme (14.2571 ± 0.51 and 15.3326 ± 0.51 μmol/min/mg larval protein) and total protein levels (0.0390 ± 0.008 and 0.1975 ± 0.029 mg/individual larva in treated groups of A. stephensi and C. quinquefasciatus at 0.1-ppm concentration, respectively. The non-target organisms such as Gambusia affinis and Diplonychus indicus were not affected. Biopesticides are good alternatives to synthetic pesticides. PONNEEM can be effectively used for the management of human vector mosquitoes. Since it has a biodegradable nature and does not alter the environmental condition of water and soil. PMID:25929457

  10. Mosquito vectors of West Nile virus during an epizootic outbreak in Puerto Rico.

    PubMed

    Barrera, R; MacKay, A; Amador, M; Vasquez, J; Smith, J; Díaz, A; Acevedo, V; Cabán, B; Hunsperger, E A; Muñoz-Jordán, J L

    2010-11-01

    The purpose of this investigation was to identify the mosquito (Diptera: Culicidae) vectors of West Nile virus (WNV; family Flaviviridae, genus Flavivirus) during an epizootic WNV outbreak in eastern Puerto Rico in 2007. In June 2006, 12 sentinel chicken pens with five chickens per pen were deployed in six types of habitats: herbaceous wetlands, mangrove forests, deciduous forests, evergreen forests, rural areas, and urban areas. Once WNV seroconversion in chickens was detected in June 2007, we began trapping mosquitoes using Centers for Disease Control and Prevention (CDC) miniature (light/CO2-baited) traps, CMT-20 collapsible mosquito (CO2- and ISCA SkinLure-baited) traps, and CDC gravid (hay infusion-baited) traps. We placed the CDC miniature traps both 2-4 m and >30 m from the chicken pens, the collapsible traps 2-4 m from the pens, and the gravid traps in backyards of houses with sentinel chicken pens and in a wetland adjacent to an urban area. We found numerous blood-engorged mosquitoes in the traps nearest to the sentinel chickens and reasoned that any such mosquitoes with a disseminated WNV infection likely served as vectors for the transmission of WNV to the sentinels. We used reverse transcriptase-polymerase chain reaction and isolation (C636) on pools of heads, thoraxes/ abdomens, and legs of collected blood-engorged mosquitoes to determine whether the mosquitoes carried WNV. We detected WNV-disseminated infections in and obtained WNV isolates from Culex nigripalpus Theo (minimum infection rate [MIR] 1.1-9.7/1,000), Culex bahamensis Dyar and Knab (MIR 1.8-6.0/1,000), and Aedes taeniorhynchus (Wied.) (MIR 0.34-0.36/1,000). WNV was also identified in and isolated from the pool of thoraxes and abdomens of Culex quinquefasciatus Say (4.17/1,000) and identified in one pool of thoraxes and abdomens of Culex habilitator Dyar and Knab (13.39/1,000). Accumulated evidence since 2002 suggests that WNV has not become endemic in Puerto Rico. PMID:21175071

  11. Laboratory evaluation of Indian medicinal plants as repellents against malaria, dengue, and filariasis vector mosquitoes.

    PubMed

    Govindarajan, Marimuthu; Sivakumar, Rajamohan

    2015-02-01

    Mosquito-borne diseases have an economic impact, including loss in commercial and labor outputs, particularly in countries with tropical and subtropical climates; however, no part of the world is free from vector-borne diseases. 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. In view of the recently increased interest in developing plant origin insecticides as an alternative to chemical insecticides, in the present study, the repellent activity of crude hexane, ethyl acetate, benzene, chloroform, and methanol extracts of leaf of Erythrina indica and root of Asparagus racemosus were assayed for their repellency against three important vector mosquitoes, viz., Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. The crude extract was applied on a membrane used for membrane feeding of unfed mosquitoes in a 1-ft cage. About 50 unfed 3-4-day-old laboratory-reared pathogen-free strains of A. stephensi, A. aegypti, and C. quinquefasciatus were introduced in a 1-ft cage fitted with a membrane with blood for feeding with temperature maintained at 37 °C through circulating water bath maintained at 40-45 °C. Three concentrations (1.0, 2.0, and 5.0 mg/cm(2)) of the crude extracts were evaluated. Repellents in E. indica afforded longer protection time against A. stephensi, A. aegypti, and C. quinquefasciatus than those in A. racemosus at 5.0 mg/cm(2) concentration, and the mean complete protection time ranged from 120 to 210 min with the different extracts tested. In this observation, these two plant crude extracts gave protection against mosquito bites; also, the repellent activity is dependent on the strength of the plant extracts. These results suggest that the leaf extract of E. indica and root extract of A. racemosus have the potential to

  12. Effect of Trapping Methods, Weather, and Landscape on Estimates of the Culex Vector Mosquito Abundance.

    PubMed

    Karki, Surendra; Hamer, Gabriel L; Anderson, Tavis K; Goldberg, Tony L; Kitron, Uriel D; Krebs, Bethany L; Walker, Edward D; Ruiz, Marilyn O

    2016-01-01

    The local abundance of Culex mosquitoes is a central factor adding to the risk of West Nile virus transmission, and vector abundance data influence public health decisions. This study evaluated differences in abundance estimates from mosquitoes trapped using two common methods: CO2-baited CDC light traps and infusion-baited gravid traps in suburban, Chicago, Illinois. On a weekly basis, the two methods were modestly correlated (r = 0.219) across 71 weeks over 4 years. Lagged weather conditions of up to four weeks were associated with the number of mosquitoes collected in light and gravid traps. Collections in light traps were higher with higher temperature in the same week, higher precipitation one, two, and four weeks before the week of trapping, and lower maximum average wind speed. Collections in gravid traps were higher with higher temperature in the same week and one week earlier, lower temperature four weeks earlier, and with higher precipitation two and four weeks earlier. Culex abundance estimates from light traps were significantly higher in semi-natural areas compared to residential areas, but abundance estimates from gravid traps did not vary by the landscape type. These results highlight the importance of the surveillance methods used in the assessment of local Culex abundance estimates. Measures of risk of exposure to West Nile virus should assess carefully how mosquito abundance has been estimated and integrated into assessments of transmission risk. PMID:27375359

  13. Effect of Trapping Methods, Weather, and Landscape on Estimates of the Culex Vector Mosquito Abundance

    PubMed Central

    Karki, Surendra; Hamer, Gabriel L.; Anderson, Tavis K.; Goldberg, Tony L.; Kitron, Uriel D.; Krebs, Bethany L.; Walker, Edward D.; Ruiz, Marilyn O.

    2016-01-01

    The local abundance of Culex mosquitoes is a central factor adding to the risk of West Nile virus transmission, and vector abundance data influence public health decisions. This study evaluated differences in abundance estimates from mosquitoes trapped using two common methods: CO2-baited CDC light traps and infusion-baited gravid traps in suburban, Chicago, Illinois. On a weekly basis, the two methods were modestly correlated (r = 0.219) across 71 weeks over 4 years. Lagged weather conditions of up to four weeks were associated with the number of mosquitoes collected in light and gravid traps. Collections in light traps were higher with higher temperature in the same week, higher precipitation one, two, and four weeks before the week of trapping, and lower maximum average wind speed. Collections in gravid traps were higher with higher temperature in the same week and one week earlier, lower temperature four weeks earlier, and with higher precipitation two and four weeks earlier. Culex abundance estimates from light traps were significantly higher in semi-natural areas compared to residential areas, but abundance estimates from gravid traps did not vary by the landscape type. These results highlight the importance of the surveillance methods used in the assessment of local Culex abundance estimates. Measures of risk of exposure to West Nile virus should assess carefully how mosquito abundance has been estimated and integrated into assessments of transmission risk. PMID:27375359

  14. Diversity and ecology survey of mosquitoes potential vectors in Belgian equestrian farms: A threat prevention of mosquito-borne equine arboviruses.

    PubMed

    Boukraa, Slimane; de La Grandiere, Maria A; Bawin, Thomas; Raharimalala, Fara N; Zimmer, Jean-Yves; Haubruge, Eric; Thiry, Etienne; Francis, Frédéric

    2016-02-01

    Emergence of West Nile Virus was recently recorded in several European countries, which can lead to severe health problems in horse populations. Europe is also at risk of introduction of mosquito-borne equine alphavirus from Americas. Prevention of these arboviruses requires a clear understanding of transmission cycles, especially their vectors. To characterize mosquito fauna, their ecology and identify potential vectors of equine arboviruses in Belgium, entomological surveys of six equestrian farms located in the Wolloon Region were conducted during 2011-2012. The harvest of mosquitoes was based on larval sampling (272 samples from 111 breeding sites) and monthly adults trapping (CO2-baited traps, Mosquito Magnet Liberty Plus). Among 51,493 larvae and 319 adult mosquitoes collected, morphological identification showed the presence of 11 species: Anopheles claviger (Meigen), An. maculipennis s.l. (Meigen), An. plumbeus (Stephens), Culex hortensis (Ficalbi), Cx. territans (Walker), Cx. pipiens s.l. L., Cx. torrentium (Martini), Coquillettidia richiardii (Ficalbi), Culiseta annulata (Schrank), Aedes cantans (Meigen), Ae. geniculatus (Olivier). Molecular identification of Cx. pipiens species complex allowed the detection of three molecular forms, Pipiens (92.3%), Molestus (4.6%) and Hybrid (3.1%). Larvae of Cx. pipiens sl and Cx. torrentium were omnipresent and the most abundant species. Water troughs, ponds and slurry (liquid manure) were the most favorable breeding sites of mosquito larvae. Based upon behavior and ecology of the identified mosquito species, Studied Belgian equestrian farms seem to provide a suitable environment and breeding sites for the proliferation of potential vectors of arboviruses and those being a real nuisance problem for horses and neighboring inhabitants. PMID:26775817

  15. Impact of naled (Dibrom 14) on the mosquito vectors of eastern equine encephalitis virus.

    PubMed

    Howard, J J; Oliver, J

    1997-12-01

    In central New York, aerial mosquito adulticide applications have been used in response to eastern equine encephalitis (EEE) outbreaks and have targeted the swamp habitats of the primary enzootic vector of EEE virus, Culiseta melanura (Coquillett). The organophosphate insecticide naled (1, 2, dibromo-2, 2-dichloroethyl dimethyl phosphate) has been the insecticide of choice in this region. This study reports on analyses of 11 years (1984-94) of mosquito collection data from Cicero and Toad Harbor swamps in relation to applications of naled. Naled applications were successful in achieving short-term reductions in mosquito abundance. However, despite repetitive applications, populations of the primary vector of EEE virus, Cs. melanura, have increased 15-fold at Cicero Swamp. Preventive applications had no noticeable impact on the enzootic amplification of EEE virus, and isolations of virus following preventive applications have resulted in additional spraying. The possibility that applications of naled contributed to increased populations of Cs. melanura discredits the rationale that preventive applications of naled reduce the risk of EEE. PMID:9474556

  16. Development of a population suppression strain of the human malaria vector mosquito, Anopheles stephensi

    PubMed Central

    2013-01-01

    Background Transgenic mosquito strains are being developed to contribute to the control of dengue and malaria transmission. One approach uses genetic manipulation to confer conditional, female-specific dominant lethality phenotypes. Engineering of a female-specific flightless phenotype provides a sexing mechanism essential for male-only mosquito, release approaches that result in population suppression of target vector species. Methods An approach that uses a female-specific gene promoter and antibiotic-repressible lethal factor to produce a sex-specific flightless phenotype was adapted to the human malaria vector, Anopheles stephensi. Transposon- and site-specific recombination-mediated technologies were used to generate a number of transgenic An. stephensi lines that when combined through mating produced the phenotype of flight-inhibited females and flight-capable males. Results The data shown here demonstrate the successful engineering of a female-specific flightless phenotype in a malaria vector. The flightless phenotype was repressible by the addition of tetracycline to the larval diet. This conditional phenotype allows the rearing of the strains under routine laboratory conditions. The minimal level of tetracycline that rescues the flightless phenotype is higher than that found as an environmental contaminant in circumstances where there is intensive use of antibiotics. Conclusions These studies support the further development of flightless female technology for applications in malaria control programmes that target the vectors. PMID:23622561

  17. Mosquito vector diversity across habitats in central Thailand endemic for dengue and other arthropod-borne diseases.

    PubMed

    Thongsripong, Panpim; Green, Amy; Kittayapong, Pattamaporn; Kapan, Durrell; Wilcox, Bruce; Bennett, Shannon

    2013-01-01

    Recent years have seen the greatest ecological disturbances of our times, with global human expansion, species and habitat loss, climate change, and the emergence of new and previously-known infectious diseases. Biodiversity loss affects infectious disease risk by disrupting normal relationships between hosts and pathogens. Mosquito-borne pathogens respond to changing dynamics on multiple transmission levels and appear to increase in disturbed systems, yet current knowledge of mosquito diversity and the relative abundance of vectors as a function of habitat change is limited. We characterize mosquito communities across habitats with differing levels of anthropogenic ecological disturbance in central Thailand. During the 2008 rainy season, adult mosquito collections from 24 sites, representing 6 habitat types ranging from forest to urban, yielded 62,126 intact female mosquitoes (83,325 total mosquitoes) that were assigned to 109 taxa. Female mosquito abundance was highest in rice fields and lowest in forests. Diversity indices and rarefied species richness estimates indicate the mosquito fauna was more diverse in rural and less diverse in rice field habitats, while extrapolated estimates of true richness (Chao1 and ACE) indicated higher diversity in the forest and fragmented forest habitats and lower diversity in the urban. Culex sp. (Vishnui subgroup) was the most common taxon found overall and the most frequent in fragmented forest, rice field, rural, and suburban habitats. The distributions of species of medical importance differed significantly across habitat types and were always lowest in the intact, forest habitat. The relative abundance of key vector species, Aedes aegypti and Culex quinquefasciatus, was negatively correlated with diversity, suggesting that direct species interactions and/or habitat-mediated factors differentially affecting invasive disease vectors may be important mechanisms linking biodiversity loss to human health. Our results are an

  18. Mosquito Vector Diversity across Habitats in Central Thailand Endemic for Dengue and Other Arthropod-Borne Diseases

    PubMed Central

    Thongsripong, Panpim; Green, Amy; Kittayapong, Pattamaporn; Kapan, Durrell; Wilcox, Bruce; Bennett, Shannon

    2013-01-01

    Recent years have seen the greatest ecological disturbances of our times, with global human expansion, species and habitat loss, climate change, and the emergence of new and previously-known infectious diseases. Biodiversity loss affects infectious disease risk by disrupting normal relationships between hosts and pathogens. Mosquito-borne pathogens respond to changing dynamics on multiple transmission levels and appear to increase in disturbed systems, yet current knowledge of mosquito diversity and the relative abundance of vectors as a function of habitat change is limited. We characterize mosquito communities across habitats with differing levels of anthropogenic ecological disturbance in central Thailand. During the 2008 rainy season, adult mosquito collections from 24 sites, representing 6 habitat types ranging from forest to urban, yielded 62,126 intact female mosquitoes (83,325 total mosquitoes) that were assigned to 109 taxa. Female mosquito abundance was highest in rice fields and lowest in forests. Diversity indices and rarefied species richness estimates indicate the mosquito fauna was more diverse in rural and less diverse in rice field habitats, while extrapolated estimates of true richness (Chao1 and ACE) indicated higher diversity in the forest and fragmented forest habitats and lower diversity in the urban. Culex sp. (Vishnui subgroup) was the most common taxon found overall and the most frequent in fragmented forest, rice field, rural, and suburban habitats. The distributions of species of medical importance differed significantly across habitat types and were always lowest in the intact, forest habitat. The relative abundance of key vector species, Aedes aegypti and Culex quinquefasciatus, was negatively correlated with diversity, suggesting that direct species interactions and/or habitat-mediated factors differentially affecting invasive disease vectors may be important mechanisms linking biodiversity loss to human health. Our results are an

  19. miRNA genes of an invasive vector mosquito, Aedes albopictus.

    PubMed

    Gu, Jinbao; Hu, Wanqi; Wu, Jinya; Zheng, Peiming; Chen, Maoshan; James, Anthony A; Chen, Xiaoguang; Tu, Zhijian

    2013-01-01

    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. PMID:23840875

  20. Identification and genetic characterization of chikungunya virus from Aedes mosquito vector collected in the Lucknow district, North India.

    PubMed

    Nyari, N; Maan, H S; Sharma, S; Pandey, S N; Dhole, T N

    2016-06-01

    Chikungunya fever is an emerging mosquito-borne disease caused by the infection with chikungunya virus (CHIKV). The CHIKV has been rarely detected in mosquito vectors from Northern India, since vector surveillance is an effective strategy in controlling and preventing CHIKV transmission. Thus, virological investigation for CHIKV among mosquitoes of Aedes (A.) species was carried out in the Lucknow district during March 2010 to October 2011. We collected adult mosquitoes from areas with CHIKV positive patients. The adult Aedes mosquito samples were pooled, homogenized, clarified and tested for CHIKV by nonstructural protein 1 (nsP1) gene based polymerase chain reaction (PCR). A total 91 mosquito pools comprising of adult A. aegypti and A. albopictus were tested for CHIKV. The partial envelope protein (E1) gene sequences of mosquito-borne CHIKV strains were analyzed for genotyping. Of 91 pools, 6 pools of A. aegypti; and 2 pools of A. albopictus mosquitoes were identified positive for CHIKV by PCR. The phylogenetic analysis revealed clustering of CHIKV strains in two sub-lineages within the monophyletic East-Central South African (ECSA) genotype. Novel amino acid changes at the positions 294 (P294L) and 295 (S295F) were observed during analysis of amino acid sequence of the partial E1 gene. This study demonstrates the genetic diversity of circulating CHIKV strains and reports the first detection of CHIKV strains in Aedes vector species from the state of Uttar Pradesh. These findings have implication for vector control strategies to mitigate vector population to prevent the likelihood of CHIKV epidemic in the near future. PMID:26943997

  1. Mosquito vector biology and control in latin america-a 24th symposium.

    PubMed

    Clark, Gary G; Fernández-Salas, Ildefonso

    2014-09-01

    The 24th Annual Latin American Symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 80th Annual Meeting in Seattle, WA, in February 2014. The principal objective, for the previous 23 symposia, was to promote participation in the AMCA by vector control specialists, public health workers, and academicians from Latin America. This publication includes summaries of 26 presentations that were given orally in Spanish or presented as posters by participants from Colombia, Mexico, and the USA. Topics addressed in the symposium included: surveillance, ecology, chemical control, studies of dengue viruses, and insecticide resistance associated with Aedes aegypti; Anopheles vectors of malaria; essential oils; and ethnic groups and vector-borne diseases. PMID:25843096

  2. Genetic Drift during Systemic Arbovirus Infection of Mosquito Vectors Leads to Decreased Relative Fitness during Host Switching.

    PubMed

    Grubaugh, Nathan D; Weger-Lucarelli, James; Murrieta, Reyes A; Fauver, Joseph R; Garcia-Luna, Selene M; Prasad, Abhishek N; Black, William C; Ebel, Gregory D

    2016-04-13

    The emergence of mosquito-borne RNA viruses, such as West Nile virus (WNV), is facilitated by genetically complex virus populations within hosts. Here, we determine whether WNV enzootic (Culex tarsalis, Cx. quinquefasciatus, and Cx. pipiens) and bridge vectors (Aedes aegypti) have differential impacts on viral mutational diversity and fitness. During systemic mosquito infection, WNV faced stochastic reductions in genetic diversity that rapidly was recovered during intra-tissue population expansions. Interestingly, this intrahost selection and diversification was mosquito species dependent with Cx. tarsalis and Cx. quinquefasciatus exhibiting greater WNV divergence. However, recovered viral populations contained a preponderance of potentially deleterious mutations (i.e., high mutational load) and had lower relative fitness in avian cells compared to input virus. These findings demonstrate that the adaptive potential associated with mosquito transmission varies depending on the mosquito species and carries a significant fitness cost in vertebrates. PMID:27049584

  3. Modeling the spatial distribution of mosquito vectors for West Nile virus in Connecticut, USA.

    PubMed

    Diuk-Wasser, Maria A; Brown, Heidi E; Andreadis, Theodore G; Fish, Durland

    2006-01-01

    The risk of transmission of West Nile virus (WNV) to humans is associated with the density of infected vector mosquitoes in a given area. Current technology for estimating vector distribution and abundance is primarily based on Centers for Disease Control and Prevention (CDC) light trap collections, which provide only point data. In order to estimate mosquito abundance in areas not sampled by traps, we developed logistic regression models for five mosquito species implicated as the most likely vectors of WNV in Connecticut. Using data from 32 traps in Fairfield County from 2001 to 2003, the models were developed to predict high and low abundance for every 30 x 30 m pixel in the County. They were then tested with an independent dataset from 16 traps in adjacent New Haven County. Environmental predictors of abundance were extracted from remotely sensed data. The best predictive models included non-forested areas for Culex pipiens, surface water and distance to estuaries for Cx. salinarius, surface water and grasslands/agriculture for Aedes vexans and seasonal difference in the normalized difference vegetation index and distance to palustrine habitats for Culiseta melanura. No significant predictors were found for Cx. restuans. The sensitivity of the models ranged from 75% to 87.5% and the specificity from 75% to 93.8%. In New Haven County, the models correctly classified 81.3% of the traps for Cx. pipiens, 75.0% for Cx. salinarius, 62.5% for Ae. vexans, and 75.0% for Cs. melanura. Continuous surface maps of habitat suitability were generated for each species for both counties, which could contribute to future surveillance and intervention activities. PMID:16989568

  4. DNA barcoding and molecular evolution of mosquito vectors of medical and veterinary importance.

    PubMed

    Murugan, Kadarkarai; Vadivalagan, Chithravel; Karthika, Pushparaj; Panneerselvam, Chellasamy; Paulpandi, Manickam; Subramaniam, Jayapal; Wei, Hui; Aziz, Al Thabiani; Alsalhi, Mohamad Saleh; Devanesan, Sandhanasamy; Nicoletti, Marcello; Paramasivan, Rajaiah; Parajulee, Megha N; Benelli, Giovanni

    2016-01-01

    Mosquitoes (Diptera: Culicidae) are a key threat for millions of people worldwide, since they act as vectors for devastating pathogens and parasites. The standard method of utilisation of morphological characters becomes challenging due to various factors such as phenotypical variations. We explored the complementary approach of CO1 gene-based identification, analysing ten species of mosquito vectors belonging to three genera, Aedes, Culex and Anopheles from India. Analysed nucleotide sequences were found without pseudo genes and indels; they match with high similarity in nucleotide Basic Local Alignment Search Tool (BLASTn) search. The partial CO1 sequence of Anopheles niligricus was the first time record submitted to National Center for Biotechnology Information (NCBI). Mean intra- and interspecies divergence was found to be 1.30 and 3.83 %, respectively. The congeneric divergence was three times higher than the conspecifics. Deep intraspecific divergence was noted in three of the species, and the reason could be explained more accurately in the future by improving the sample size across different locations. The transitional and transversional substitutions were tested individually. Ts and Tv substitutions in all the 1st, 2nd and 3rd codons were estimated to be (0.44, 99.51), (40.35, 59.66) and (59.16, 40.84), respectively. Saturation of the sequences was resolved, since both the Ts and Tv exhibited a linear relationship suggesting that the sequences were not saturated. NJ and ML tree analysis showed that the individuals of the same species clustered together based on the CO1 sequence similarity, regardless of their collection site and geographic location. Overall, this study adds basic knowledge to molecular evolution of mosquito vectors of medical and veterinary importance and may be useful to improve biotechnological tools employed in Culicidae control programmes. PMID:26358100

  5. Global Climate Change and Its Potential Impact on Disease Transmission by Salinity-Tolerant Mosquito Vectors in Coastal Zones

    PubMed Central

    Ramasamy, Ranjan; Surendran, Sinnathamby Noble

    2012-01-01

    Global climate change can potentially increase the transmission of mosquito vector-borne diseases such as malaria, lymphatic filariasis, and dengue in many parts of the world. These predictions are based on the effects of changing temperature, rainfall, and humidity on mosquito breeding and survival, the more rapid development of ingested pathogens in mosquitoes and the more frequent blood feeds at moderately higher ambient temperatures. An expansion of saline and brackish water bodies (water with <0.5 ppt or parts per thousand, 0.5–30 ppt and >30 ppt salt are termed fresh, brackish, and saline respectively) will also take place as a result of global warming causing a rise in sea levels in coastal zones. Its possible impact on the transmission of mosquito-borne diseases has, however, not been adequately appreciated. The relevant impacts of global climate change on the transmission of mosquito-borne diseases in coastal zones are discussed with reference to the Ross–McDonald equation and modeling studies. Evidence is presented to show that an expansion of brackish water bodies in coastal zones can increase the densities of salinity-tolerant mosquitoes like Anopheles sundaicus and Culex sitiens, and lead to the adaptation of fresh water mosquito vectors like Anopheles culicifacies, Anopheles stephensi, Aedes aegypti, and Aedes albopictus to salinity. Rising sea levels may therefore act synergistically with global climate change to increase the transmission of mosquito-borne diseases in coastal zones. Greater attention therefore needs to be devoted to monitoring disease incidence and preimaginal development of vector mosquitoes in artificial and natural coastal brackish/saline habitats. It is important that national and international health agencies are aware of the increased risk of mosquito-borne diseases in coastal zones and develop preventive and mitigating strategies. Application of appropriate counter measures can greatly reduce the potential for

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

    PubMed Central

    2014-01-01

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

  7. Dynamics of the "popcorn" Wolbachia infection in outbred Aedes aegypti informs prospects for mosquito vector control.

    PubMed

    Yeap, H L; Mee, P; Walker, T; Weeks, A R; O'Neill, S L; Johnson, P; Ritchie, S A; Richardson, K M; Doig, C; Endersby, N M; Hoffmann, A A

    2011-02-01

    Forty percent of the world's population is at risk of contracting dengue virus, which produces dengue fever with a potentially fatal hemorrhagic form. The wMelPop Wolbachia infection of Drosophila melanogaster reduces life span and interferes with viral transmission when introduced into the mosquito Aedes aegypti, the primary vector of dengue virus. Wolbachia has been proposed as an agent for preventing transmission of dengue virus. Population invasion by Wolbachia depends on levels of cytoplasmic incompatibility, fitness effects, and maternal transmission. Here we characterized these traits in an outbred genetic background of a potential target population of Ae. aegypti using two crossing schemes. Cytoplasmic incompatibility was strong in this background, and the maternal transmission rate of Wolbachia was high. The infection substantially reduced longevity of infected adult females, regardless of whether adults came from larvae cultured under high or low levels of nutrition or density. The infection reduced the viability of diapausing and nondiapausing eggs. Viability was particularly low when eggs were laid by older females and when diapausing eggs had been stored for a few weeks. The infection affected mosquito larval development time and adult body size under different larval nutrition levels and densities. The results were used to assess the potential for wMelPop-CLA to invade natural populations of Ae. aegypti and to develop recommendations for the maintenance of fitness in infected mosquitoes that need to compete against field insects. PMID:21135075

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

    PubMed Central

    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

  9. Circulation of Japanese Encephalitis Virus in Pigs and Mosquito Vectors within Can Tho City, Vietnam

    PubMed Central

    Lindahl, Johanna F.; Ståhl, Karl; Chirico, Jan; Boqvist, Sofia; Thu, Ho Thi Viet; Magnusson, Ulf

    2013-01-01

    Japanese encephalitis virus (JEV) is a mosquito-borne, zoonotic flavivirus causing encephalitis in humans and reproductive disorder in pigs. JEV is present in large parts of Asia, where urbanization is high. Households within and outside Can Tho city, South Vietnam, were selected to monitor circulation of JEV. A nested RT-PCR was established to detect the presence of JEV in mosquitoes whereas sera from pigs belonging to households within the province were analyzed for the presence of antibodies to JEV. A total of 7885 mosquitoes were collected and divided into 352 pools whereof seven were JEV-positive, six of which were collected within the city. Fragments from four pools clustered with JEV genotype III and three with genotype I. Of the 43 pigs sampled inside the city 100% had JEV antibodies. Our study demonstrates exposure to JEV in pigs, and co-circulation of JEV genotype I and III in mosquitoes within an urban environment in South Vietnam. Thus, although JEV has mainly been considered a rural disease, the potential for transmission in urban areas cannot be ignored. PMID:23593520

  10. Efficacy of Thai herbal essential oils as green repellent against mosquito vectors.

    PubMed

    Soonwera, Mayura; Phasomkusolsil, Siriporn

    2015-02-01

    Repellency activity of Thai essential oils derived from ylang ylang (Cananga odorata (Lamk.) Hook.f. & Thomson: Annonaceae) and lemongrass (Cymbopogon citratus (DC.) Stapf: Poaceae) were tested against two mosquito vectors, Aedes aegypti (L.) and Culex quinquefasciatus (Say). There were compared with two chemical repellents (DEET 20% w/w; Sketolene Shield(®) and IR3535, ethyl butylacetylaminopropionate 12.5% w/w; Johnson's Baby Clear Lotion Anti-Mosquito(®)). Each herbal repellent was applied in three diluents; coconut oil, soybean oil and olive oil at 0.33 μl/cm(2) on the forearm of volunteers. All herbal repellent exhibited higher repellent activity than IR3535 12.5% w/w, but lower repellent activity than DEET 20% w/w. The C. odorata oil in coconut oil exhibited excellent activity with 98.9% protection from bites of A. aegypti for 88.7±10.4 min. In addition, C. citratus in olive oil showed excellent activity with 98.8% protection from bites of C. quinquefasciatus for 170.0±9.0 min. While, DEET 20% w/w gave protection for 155.0±7.1-182.0±12.2 min and 98.5% protection from bites of two mosquito species. However, all herbal repellent provided lower repellency activity (97.4-98.9% protection for 10.5-88.7 min) against A. aegypti than C. quinquefasciatus (98.3-99.2% protection for 60-170 min). Our data exhibited that C. odorata oil and C. citratus oil are suitable to be used as green repellents for mosquito control, which are safe for humans, domestic animals and environmental friendly. PMID:25438256

  11. Mosquito vectors developing in atypical anthropogenic habitats: Global overview of recent observations, mechanisms and impact on disease transmission.

    PubMed

    Ramasamy, Ranjan; Surendran, Sinnathamby N

    2016-01-01

    The major mosquito vectors of human diseases have co-evolved with humans over a long period of time. However, the rapid growth in human population and the associated expansion in agricultural activity and greater urbanisation have created ecological changes that have had a marked impact on biology of mosquito vectors. Adaptation of the vectors of malaria and important arbovial diseases over a much shorter time scale to the new types of preimaginal habitats recently created by human population growth and activity is highlighted here in the context of its potential for increasing disease transmission rates. Possible measures that can reduce the effects on the transmission of mosquito-borne diseases are also outlined. PMID:27353577

  12. Antipathogen genes and the replacement of disease-vectoring mosquito populations: a model-based evaluation.

    PubMed

    Robert, Michael A; Okamoto, Kenichi W; Gould, Fred; Lloyd, Alun L

    2014-12-01

    Recently, genetic strategies aimed at controlling populations of disease-vectoring mosquitoes have received considerable attention as alternatives to traditional measures. Theoretical studies have shown that female-killing (FK), antipathogen (AP), and reduce and replace (R&R) strategies can each decrease the number competent vectors. In this study, we utilize a mathematical model to evaluate impacts on competent Aedes aegypti populations of FK, AP, and R&R releases as well as hybrid strategies that result from combinations of these three approaches. We show that while the ordering of efficacy of these strategies depends upon population life history parameters, sex ratio of releases, and switch time in combination strategies, AP-only and R&R/AP releases typically lead to the greatest long-term reduction in competent vectors. R&R-only releases are often less effective at long-term reduction of competent vectors than AP-only releases or R&R/AP releases. Furthermore, the reduction in competent vectors caused by AP-only releases is easier to maintain than that caused by FK-only or R&R-only releases even when the AP gene confers a fitness cost. We discuss the roles that density dependence and inclusion of females play in the order of efficacy of the strategies. We anticipate that our results will provide added impetus to continue developing AP strategies. PMID:25558284

  13. Antipathogen genes and the replacement of disease-vectoring mosquito populations: a model-based evaluation

    PubMed Central

    Robert, Michael A; Okamoto, Kenichi W; Gould, Fred; Lloyd, Alun L

    2014-01-01

    Recently, genetic strategies aimed at controlling populations of disease-vectoring mosquitoes have received considerable attention as alternatives to traditional measures. Theoretical studies have shown that female-killing (FK), antipathogen (AP), and reduce and replace (R&R) strategies can each decrease the number competent vectors. In this study, we utilize a mathematical model to evaluate impacts on competent Aedes aegypti populations of FK, AP, and R&R releases as well as hybrid strategies that result from combinations of these three approaches. We show that while the ordering of efficacy of these strategies depends upon population life history parameters, sex ratio of releases, and switch time in combination strategies, AP-only and R&R/AP releases typically lead to the greatest long-term reduction in competent vectors. R&R-only releases are often less effective at long-term reduction of competent vectors than AP-only releases or R&R/AP releases. Furthermore, the reduction in competent vectors caused by AP-only releases is easier to maintain than that caused by FK-only or R&R-only releases even when the AP gene confers a fitness cost. We discuss the roles that density dependence and inclusion of females play in the order of efficacy of the strategies. We anticipate that our results will provide added impetus to continue developing AP strategies. PMID:25558284

  14. Visual arrestins in olfactory pathways of Drosophila and the malaria vector mosquito Anopheles gambiae

    PubMed Central

    Merrill, C. E.; Riesgo-Escovar, J.; Pitts, R. J.; Kafatos, F. C.; Carlson, J. R.; Zwiebel, L. J.

    2002-01-01

    Arrestins are important components for desensitization of G protein-coupled receptor cascades that mediate neurotransmission as well as olfactory and visual sensory reception. We have isolated AgArr1, an arrestin-encoding cDNA from the malaria vector mosquito, Anopheles gambiae, where olfaction is critical for vectorial capacity. Analysis of AgArr1 expression revealed an overlap between chemosensory and photoreceptor neurons. Furthermore, an examination of previously identified arrestins from Drosophila melanogaster exposed similar bimodal expression, and Drosophila arrestin mutants demonstrate impaired electrophysiological responses to olfactory stimuli. Thus, we show that arrestins in Drosophila are required for normal olfactory physiology in addition to their previously described role in visual signaling. These findings suggest that individual arrestins function in both olfactory and visual pathways in Dipteran insects; these genes may prove useful in the design of control strategies that target olfactory-dependent behaviors of insect disease vectors. PMID:11792843

  15. Plant-borne ovicides in the fight against mosquito vectors of medical and veterinary importance: a systematic review.

    PubMed

    Benelli, Giovanni

    2015-09-01

    Mosquitoes (Diptera: Culicidae) are a huge threat for millions of people worldwide, since they act as vectors for devastating parasites and pathogens. Culicidae control is of crucial importance. Mosquito eggs, larvae, and pupae 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 species. Eco-friendly tools have been recently implemented against mosquito vectors, including botanical insecticides. The majority of researches focused on larvicides (745 SCOPUS results, July 2015) and adult repellents (434 SCOPUS results), while limited efforts were conducted to identify effective ovicides of botanical origin (59 SCOPUS results). Here, I review current knowledge on the effectiveness of plant-borne ovicides against major mosquito vectors of medical and veterinary importance. The majority of researches focused on the toxicity of crude extracts, their fractions, or essential oils against three important mosquito vectors, Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. As a general trend, C. quinquefasciatus eggs were the most resistant to botanical ovicides. Five studies proposed selected compounds from plant extracts and essential oils as ovicides effective at few parts per million. However, no efforts were conducted to shed light on possible mechanisms underlying the toxicity of plant-borne ovicides. In the final section, a number of hot issues needing further research and cooperation among parasitologists, entomologists, and researchers working in natural product chemistry are outlined. PMID:26239801

  16. Distribution of the main malaria vectors in Kenya

    PubMed Central

    2010-01-01

    Background A detailed knowledge of the distribution of the main Anopheles malaria vectors in Kenya should guide national vector control strategies. However, contemporary spatial distributions of the locally dominant Anopheles vectors including Anopheles gambiae, Anopheles arabiensis, Anopheles merus, Anopheles funestus, Anopheles pharoensis and Anopheles nili are lacking. The methods and approaches used to assemble contemporary available data on the present distribution of the dominant malaria vectors in Kenya are presented here. Method Primary empirical data from published and unpublished sources were identified for the period 1990 to 2009. Details recorded for each source included the first author, year of publication, report type, survey location name, month and year of survey, the main Anopheles species reported as present and the sampling and identification methods used. Survey locations were geo-positioned using national digital place name archives and on-line geo-referencing resources. The geo-located species-presence data were displayed and described administratively, using first-level administrative units (province), and biologically, based on the predicted spatial margins of Plasmodium falciparum transmission intensity in Kenya for the year 2009. Each geo-located survey site was assigned an urban or rural classification and attributed an altitude value. Results A total of 498 spatially unique descriptions of Anopheles vector species across Kenya sampled between 1990 and 2009 were identified, 53% were obtained from published sources and further communications with authors. More than half (54%) of the sites surveyed were investigated since 2005. A total of 174 sites reported the presence of An. gambiae complex without identification of sibling species. Anopheles arabiensis and An. funestus were the most widely reported at 244 and 265 spatially unique sites respectively with the former showing the most ubiquitous distribution nationally. Anopheles gambiae

  17. Ethnobotanical knowledge on botanical repellents employed in the African region against mosquito vectors - A review.

    PubMed

    Pavela, Roman; Benelli, Giovanni

    2016-08-01

    Mosquitoes (Diptera: Culicidae) represent a huge threat for millions of humans and animals worldwide, since they act as vectors for important parasites and pathogens, including malaria, filariasis and important arboviruses, such as dengue, West Nile and Zika virus. No vaccines or other specific treatments are available against the arboviruses transmitted by mosquitoes, and avoidance of mosquito bites remains the best strategy. African regions are usually hit most whose inhabitants are poor, and the use of repellent plants is the only efficient protection against vectors they have. Ethnobotanical knowledge of such plants and their use is usually passed on orally from one generation to another. However, it is also important to preserve this information in a written form, as well. Ethnobotanical research projects carried out in the regions of today's Ethiopia, South Africa, Nigeria, Kenya, and Tanzania indicate that the native inhabitants of the African study regions traditionally use 64 plant species, belonging to 30 families. Aromatic plants (i.e., Citrus spp., Eucalyptus spp., Lantana camara, Ocimum spp. and Lippia javanica) the most commonly used in all the study regions. Native people know three major methods of using repellent plants: (i) production of repellent smoke from burning plants, (ii) hanging plants inside the house or sprinkling leaves on the floor, (iii) the use of plant oils, juices from crushed fresh parts of the plants, or various prepared extracts applied on uncovered body parts. Overall, this review covers studies conducted only in a limited part of the African continent, highlighting the importance to undertake further research efforts to preserve the unique knowledge and traditions of the native tribes. PMID:27260568

  18. Landscape Movements of Anopheles gambiae Malaria Vector Mosquitoes in Rural Gambia

    PubMed Central

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

    2013-01-01

    Background 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. Methods/Principal Findings 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. Conclusions/Significance 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. PMID:23874719

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

    PubMed Central

    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. PMID:24688786

  20. Simulation Modelling of Population Dynamics of Mosquito Vectors for Rift Valley Fever Virus in a Disease Epidemic Setting

    PubMed Central

    Mweya, Clement N.; Holst, Niels; Mboera, Leonard E. G.; Kimera, Sharadhuli I.

    2014-01-01

    Background Rift Valley Fever (RVF) is weather dependent arboviral infection of livestock and humans. Population dynamics of mosquito vectors is associated with disease epidemics. In our study, we use daily temperature and rainfall as model inputs to simulate dynamics of mosquito vectors population in relation to disease epidemics. Methods/Findings Time-varying distributed delays (TVDD) and multi-way functional response equations were implemented to simulate mosquito vectors and hosts developmental stages and to establish interactions between stages and phases of mosquito vectors in relation to vertebrate hosts for infection introduction in compartmental phases. An open-source modelling platforms, Universal Simulator and Qt integrated development environment were used to develop models in C++ programming language. Developed models include source codes for mosquito fecundity, host fecundity, water level, mosquito infection, host infection, interactions, and egg time. Extensible Markup Language (XML) files were used as recipes to integrate source codes in Qt creator with Universal Simulator plug-in. We observed that Floodwater Aedines and Culicine population continued to fluctuate with temperature and water level over simulation period while controlled by availability of host for blood feeding. Infection in the system was introduced by floodwater Aedines. Culicines pick infection from infected host once to amplify disease epidemic. Simulated mosquito population show sudden unusual increase between December 1997 and January 1998 a similar period when RVF outbreak occurred in Ngorongoro district. Conclusion/Significance Findings presented here provide new opportunities for weather-driven RVF epidemic simulation modelling. This is an ideal approach for understanding disease transmission dynamics towards epidemics prediction, prevention and control. This approach can be used as an alternative source for generation of calibrated RVF epidemics data in different settings

  1. Schools as Potential Risk Sites for Vector-Borne Disease Transmission: Mosquito Vectors in Rural Schools in Two Municipalities in Colombia.

    PubMed

    Olano, Víctor Alberto; Matiz, María Inés; Lenhart, Audrey; Cabezas, Laura; Vargas, Sandra Lucía; Jaramillo, Juan Felipe; Sarmiento, Diana; Alexander, Neal; Stenström, Thor Axel; Overgaard, Hans J

    2015-09-01

    Dengue and other vector-borne diseases are of great public health importance in Colombia. Vector surveillance and control activities are often focused at the household level. Little is known about the importance of nonhousehold sites, including schools, in maintaining vector-borne disease transmission. The objectives of this paper were to determine the mosquito species composition in rural schools in 2 municipalities in Colombia and to assess the potential risk of vector-borne disease transmission in school settings. Entomological surveys were carried out in rural schools during the dry and rainy seasons of 2011. A total of 12 mosquito species were found: Aedes aegypti, Anopheles pseudopunctipennis, Culex coronator, Cx. quinquefasciatus, and Limatus durhamii in both immature and adult forms; Ae. fluviatilis, Cx. nigripalpus, Cx. corniger, and Psorophora ferox in immature forms only; and Ae. angustivittatus, Haemagogus equinus, and Trichoprosopon lampropus in adult forms only. The most common mosquito species was Cx. quinquefasciatus. Classrooms contained the greatest abundance of adult female Ae. aegypti and Cx. quinquefasciatus. The most common Ae. aegypti breeding sites were containers classified as "others" (e.g., cans), followed by containers used for water storage. A high level of Ae. aegypti infestation was found during the wet season. Our results suggest that rural schools are potentially important foci for the transmission of dengue and other mosquito-borne diseases. We propose that public health programs should be implemented in rural schools to prevent vector-borne diseases. PMID:26375902

  2. Two step male release strategy using transgenic mosquito lines to control transmission of vector-borne diseases.

    PubMed

    Carvalho, Danilo Oliveira; Costa-da-Silva, André Luis; Lees, Rosemary Susan; Capurro, Margareth Lara

    2014-04-01

    Mosquitoes are responsible for the transmission of pathogens that cause devastating human diseases such as malaria and dengue. The current increase in mean global temperature and changing sea level interfere with precipitation frequency and some other climatic conditions which, in general, influence the rate of development of insects and etiologic agents causing acceleration as the temperature rises. The most common strategy employed to combat target mosquito species is the Integrated Vector Management (IVM), which comprises the use of multiple activities and various approaches to preventing the spread of a vector in infested areas. IVM programmes are becoming ineffective; and the global scenario is threatening, requiring new interventions for vector control and surveillance. Not surprisingly, there is a growing need to find alternative methods to combat the mosquito vectors. The possibility of using transgenic mosquitoes to fight against those diseases has been discussed over the last two decades and this use of transgenic lines to suppress populations or to replace them is still under investigation through field and laboratory trials. As an alternative, the available transgenic strategies could be improved by coupling suppression and substitution strategies. The idea is to first release a suppression line to significantly reduce the wild population, and once the first objective is reached a second release using a substitution line could be then performed. Examples of targeting this approach against vectors of malaria and dengue are discussed. PMID:24513036

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

    PubMed

    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

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

    PubMed

    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. PMID:27330557

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

    PubMed

    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. PMID:17633420

  6. Into the environment of mosquito-borne disease: A spatial analysis of vector distribution using traditional and remotely sensed methods

    NASA Astrophysics Data System (ADS)

    Brown, Heidi E.

    Spatially explicit information is increasingly available for infectious disease modeling. However, such information is reluctantly or inappropriately incorporated. My dissertation research uses spatially explicit data to assess relationships between landscape and mosquito species distribution and discusses challenges regarding accurate predictive risk modeling. The goal of my research is to use remotely sensed environmental information and spatial statistical methods to better understand mosquito-borne disease epidemiology for improvement of public health responses. In addition to reviewing the progress of spatial infectious disease modeling, I present four research projects. I begin by evaluating the biases in surveillance data and build up to predictive modeling of mosquito species presence. In the first study I explore how mosquito surveillance trap types influence estimations of mosquito populations. Then. I use county-based human surveillance data and landscape variables to identify risk factors for West Nile virus disease. The third study uses satellite-based vegetation indices to identify spatial variation among West Nile virus vectors in an urban area and relates the variability to virus transmission dynamics. Finally, I explore how information from three satellite sensors of differing spatial and spectral resolution can be used to identify and distinguish mosquito habitat across central Connecticut wetlands. Analyses presented here constitute improvements to the prediction of mosquito distribution and therefore identification of disease risk factors. Current methods for mosquito surveillance data collection are labor intensive and provide an extremely limited, incomplete picture of the species composition and abundance. Human surveillance data offers additional challenges with respect to reporting bias and resolution, but is nonetheless informative in identifying environmental risk factors and disease transmission dynamics. Remotely sensed imagery supports

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

    PubMed

    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. PMID:25792419

  8. Towards a Semen Proteome of the Dengue Vector Mosquito: Protein Identification and Potential Functions

    PubMed Central

    Sirot, Laura K.; Ribeiro, José M. C.; Kimura, Mari; Deewatthanawong, Prasit; Wolfner, Mariana F.; Harrington, Laura C.

    2011-01-01

    Background No commercially licensed vaccine or treatment is available for dengue fever, a potentially lethal infection that impacts millions of lives annually. New tools that target mosquito control may reduce vector populations and break the cycle of dengue transmission. Male mosquito seminal fluid proteins (Sfps) are one such target since these proteins, in aggregate, modulate the reproduction and feeding patterns of the dengue vector, Aedes aegypti. As an initial step in identifying new targets for dengue vector control, we sought to identify the suite of proteins that comprise the Ae. aegypti ejaculate and determine which are transferred to females during mating. Methodology and Principal Findings Using a stable-isotope labeling method coupled with proteomics to distinguish male- and female-derived proteins, we identified Sfps and sperm proteins transferred from males to females. Sfps were distinguished from sperm proteins by comparing the transferred proteins to sperm-enriched samples derived from testes and seminal vesicles. We identified 93 male-derived Sfps and 52 predicted sperm proteins that are transferred to females during mating. The Sfp protein classes we detected suggest roles in protein activation/inactivation, sperm utilization, and ecdysteroidogenesis. We also discovered that several predicted membrane-bound and intracellular proteins are transferred to females in the seminal fluids, supporting the hypothesis that Ae. aegypti Sfps are released from the accessory gland cells through apocrine secretion, as occurs in mammals. Many of the Ae. aegypti predicted sperm proteins were homologous to Drosophila melanogaster sperm proteins, suggesting conservation of their sperm-related function across Diptera. Conclusion and Significance This is the first study to directly identify Sfps transferred from male Ae. aegypti to females. Our data lay the groundwork for future functional analyses to identify individual seminal proteins that may trigger female post

  9. Vector Competence of Argentine Mosquitoes (Diptera: Culicidae) for West Nile virus (Flaviviridae: Flavivirus)

    PubMed Central

    MICIELI, MARÍA V.; MATACCHIERO, AMY C.; MUTTIS, EVANGELINA; FONSECA, DINA M.; ALIOTA, MATTHEW T.; KRAMER, LAURA D.

    2014-01-01

    We examined the ability of Culex pipiens L. complex mosquitoes from Argentina to vector West Nile virus (WNV) to assess their role in the transmission of WNV in South America. Several egg rafts of Culex spp. were collected from different breeding sites in the suburbs of the city of La Plata, Argentina, and a subset of each progeny was scored with morphological and genetic species indicators. Surprisingly, we did not find Cx. pipiens form pipiens, but found evidence of genetic hybrids of Culex quinquefasciatus and Cx. pipiens f. molestus. We then used morphological traits to create two colonies predominantly composed of one of these two taxa, although some hybrids are likely to have been included in both. These colonies were used in vector competence studies using NY99 and WN02 genotype strains of WNV obtained in New York State. As controls, we also tested colonies of U.S. Cx. quinquefasciatus and Cx. pipiens f. molestus. Additional Culex larvae from three drainage ditches near the cities of La Plata and Berisso, Argentina, were identified by morphological and high-resolution molecular markers (microsatellites) as Cx. quinquefasciatus Say, Cx. pipiens form molestus, and hybrids. Results indicate that Argentinian Culex are competent but only moderately efficient vectors of WNV and are less susceptible to this virus than comparable U.S. mosquito strains. Studies of vertical transmission of NY99 virus by Cx. pipiens f. molestus hybrids from Argentina yielded a minimal filial infection rate of 1.19 from females feeding during their second and later bloodmeals. PMID:23926785

  10. The Effect of Oral Anthelmintics on the Survivorship and Re-feeding Frequency of Anthropophilic Mosquito Disease Vectors

    PubMed Central

    Kobylinski, Kevin C.; Deus, Kelsey M.; Butters, Matt T.; Hongyu, Tan; Gray, Meg; Silva, Ines Marques da; Sylla, Massamba; Foy, Brian D.

    2010-01-01

    In the Tropics, there is substantial temporal and spatial overlap of diseases propagated by anthropophilic mosquito vectors (such as malaria and dengue) and human helminth diseases (such as onchocerciasis and lymphatic filariasis) that are treated though mass drug administrations (MDA). This overlap will result in mosquito vectors imbibing significant quantities of these drugs when they blood feed on humans. Since many anthelmintic drugs have broad anti-invertebrate effects, the possibility of combined helminth control and mosquito-borne disease control through MDA is apparent. It has been previously shown that ivermectin can reduce mosquito survivorship when administered in a blood meal, but more detailed examinations are needed if MDA is to ever be developed into a tool for malaria or dengue control. We examined concentrations of drugs that follow human pharmacokinetics after MDA and that matched with mosquito feeding times, for effects against the anthropophilic mosquito vectors Anopheles gambiae s.s. and Aedes aegypti. Ivermectin was the only human-approved MDA drug we tested that affected mosquito survivorship, and only An. gambiae s.s. were affected at concentrations respecting human pharmacokinetics at indicated doses. Ivermectin also delayed An. gambiae s.s. re-feeding frequency and defecation rates, and two successive ivermectin-spiked blood meals following human pharmacokinetic concentrations compounded mortality effects compared to controls. These findings suggest that ivermectin MDA in Africa may be used to decrease malaria transmission if MDAs were administered more frequently. Such a strategy would broaden the current scope of polyparasitism control already afforded by MDAs, and which is needed in many African villages simultaneously burdened by many parasitic diseases. PMID:20540931

  11. The effect of oral anthelmintics on the survivorship and re-feeding frequency of anthropophilic mosquito disease vectors.

    PubMed

    Kobylinski, Kevin C; Deus, Kelsey M; Butters, Matthew P; Hongyu, Tan; Gray, Meg; da Silva, Ines Marques; Sylla, Massamba; Foy, Brian D

    2010-11-01

    In the Tropics, there is substantial temporal and spatial overlap of diseases propagated by anthropophilic mosquito vectors (such as malaria and dengue) and human helminth diseases (such as onchocerciasis and lymphatic filariasis) that are treated though mass drug administrations (MDA). This overlap will result in mosquito vectors imbibing significant quantities of these drugs when they blood feed on humans. Since many anthelmintic drugs have broad anti-invertebrate effects, the possibility of combined helminth control and mosquito-borne disease control through MDA is apparent. It has been previously shown that ivermectin can reduce mosquito survivorship when administered in a blood meal, but more detailed examinations are needed if MDA is to ever be developed into a tool for malaria or dengue control. We examined concentrations of drugs that follow human pharmacokinetics after MDA and that matched with mosquito feeding times, for effects against the anthropophilic mosquito vectors Anopheles gambiae s.s. and Aedes aegypti. Ivermectin was the only human-approved MDA drug we tested that affected mosquito survivorship, and only An. gambiae s.s. were affected at concentrations respecting human pharmacokinetics at indicated doses. Ivermectin also delayed An. gambiae s.s. re-feeding frequency and defecation rates, and two successive ivermectin-spiked blood meals following human pharmacokinetic concentrations compounded mortality effects compared to controls. These findings suggest that ivermectin MDA in Africa may be used to decrease malaria transmission if MDAs were administered more frequently. Such a strategy would broaden the current scope of polyparasitism control already afforded by MDAs, and which is needed in many African villages simultaneously burdened by many parasitic diseases. PMID:20540931

  12. Monitoring the aquatic toxicity of mosquito vector control spray pesticides to freshwater receiving waters.

    PubMed

    Phillips, Bryn M; Anderson, Brian S; Voorhees, Jennifer P; Siegler, Katie; Denton, Debra; TenBrook, Patti; Larsen, Karen; Isorena, Philip; Tjeerdema, Ron S

    2014-07-01

    Pesticides are applied to state and local waterways in California to control insects such as mosquitoes, which are known to serve as a vector for West Nile Virus infection of humans. The California State Water Resources Control Board adopted a National Pollutant Discharge Elimination System General Permit to address the discharge to waters of the United States of pesticides resulting from adult and larval mosquito control. Because pesticides used in spray activities have the potential to cause toxicity to nontarget organisms in receiving waters, the current study was designed to determine whether toxicity testing provides additional, useful environmental risk information beyond chemical analysis in monitoring spray pesticide applications. Monitoring included a combination of aquatic toxicity tests and chemical analyses of receiving waters from agricultural, urban, and wetland habitats. The active ingredients monitored included the organophosphate pesticides malathion and naled, the pyrethroid pesticides etofenprox, permethrin, and sumithrin, pyrethrins, and piperonyl butoxide (PBO). Approximately 15% of the postapplication water samples were significantly toxic. Toxicity of half of these samples was attributed to the naled breakdown product dichlorvos. Toxicity of 2 other water samples likely occurred when PBO synergized the effects of pyrethroid pesticides that were likely present in the receiving system. Four of 43 postapplication sediment samples were significantly more toxic than their corresponding pre-application samples, but none of the observed toxicity was attributed to the application events. These results indicate that many of the spray pesticides used for adult mosquito control do not pose significant acute toxicity risk to invertebrates in receiving systems. In the case of naled in water, analysis of only the active ingredient underestimated potential impacts to the receiving system, because toxicity was attributed to the breakdown product, dichlorvos

  13. [Resistance of malaria vectors to pyrethrins used for impregnating mosquito nets in Benin, West Africa].

    PubMed

    Akogbéto, M; Yakoubou, S

    1999-05-01

    Impregnated bednets can be considered a major tool for reducing Anopheles bites, malaria morbidity and overall mortality. The resistance of Anopheles gambiae to pyrethroids used to impregnate bednets and curtains has already been noted in the urban area of Cotonou in Benin (18, 21). In this study, we wished to find out if the resistance observed in Cotonou is localized only in this town or is already extensive throughout Benin. In this case, such resistance would be a handicap to the promotion of impregnated bednets in Benin. The study was carried out in 15 localities throughout the different ecological zones of Benin. The study has also taken into account environmental factors favouring the emergence of resistance. We did susceptibility tests with WHO test kits for adult mosquitoes using impregnated papers. The papers were impregnated with permethrin 0.25%, deltamethrin 0.025% and lambdacyhalothrin 0.1%. We also tested DDT 4% to find out if there was a cross resistance between DDT and the pyrethroids. Two mosquito species were tested: An. gambiae and An melas. In northern Benin, where farmers use insecticides against cotton pests, vectors are susceptible to deltamethrin and lambdacyhalothrin and resistant to permethrin. In the south, An. gambiae is resistant to deltamethrin and permethrin. This resistance is high in the urban zone of Cotonou, in the coastal and lagoon areas and at Kraké, a frontier viliage with Nigeria. The resistance observed in southern Benin is confirmed by the lengthening of the knock-down time of mosquitoes which were exposed for 1 hour to insecticide in impregnated WHO test tubes, and by a reduction of permethrin and deltamethrin remanence effect. PMID:10399604

  14. piRNA pathway gene expression in the malaria vector mosquito Anopheles stephensi

    PubMed Central

    Macias, V; Coleman, J; Bonizzoni, M; James, A A

    2014-01-01

    The ability of transposons to mobilize to new places in a genome enables them to introgress rapidly into populations. The piRNA pathway has been characterized recently in the germ line of the fruit fly, Drosophila melanogaster, and is responsible for downregulating transposon mobility. Transposons have been used as tools in mosquitoes to genetically transform a number of species including Anopheles stephensi, a vector of human malaria. These mobile genetic elements also have been proposed as tools to drive antipathogen effector genes into wild mosquito populations to replace pathogen-susceptible insects with those engineered genetically to be resistant to or unable to transmit a pathogen. The piRNA pathway may affect the performance of such proposed genetic engineering strategies. In the present study, we identify and describe the An. stephensi orthologues of the major genes in the piRNA pathway, Ago3, Aubergine (Aub) and Piwi. Consistent with a role in protection from transposon movement, these three genes are expressed constitutively in the germ-line cells of ovaries and induced further after a blood meal. PMID:24947897

  15. Larvicidal Activity of Nerium oleander against Larvae West Nile Vector Mosquito Culex pipiens (Diptera: Culicidae).

    PubMed

    El-Akhal, Fouad; Guemmouh, Raja; Ez Zoubi, Yassine; El Ouali Lalami, Abdelhakim

    2015-01-01

    Background. Outbreaks of the West Nile virus infection were reported in Morocco in 1996, 2003, and 2010. Culex pipiens was strongly suspected as the vector responsible for transmission. In the North center of Morocco, this species has developed resistance to synthetic insecticides. There is an urgent need to find alternatives to the insecticides as natural biocides. Objective. In this work, the insecticidal activity of the extract of the local plant Nerium oleander, which has never been tested before in the North center of Morocco, was studied on larval stages 3 and 4 of Culex pipiens. Methods. Biological tests were realized according to a methodology inspired from standard World Health Organization protocol. The mortality values were determined after 24 h of exposure and LC50 and LC90 values were calculated. Results. The extract had toxic effects on the larvae of culicid mosquitoes. The ethanolic extract of Nerium oleander applied against the larvae of Culex pipiens has given the lethal concentrations LC50 and LC90 in the order of 57.57 mg/mL and 166.35 mg/mL, respectively. Conclusion. This investigation indicates that N. oleander could serve as a potential larvicidal, effective natural biocide against mosquito larvae, particularly Culex pipiens. PMID:26640701

  16. Larvicidal Activity of Nerium oleander against Larvae West Nile Vector Mosquito Culex pipiens (Diptera: Culicidae)

    PubMed Central

    El-Akhal, Fouad; Guemmouh, Raja; Ez Zoubi, Yassine; El Ouali Lalami, Abdelhakim

    2015-01-01

    Background. Outbreaks of the West Nile virus infection were reported in Morocco in 1996, 2003, and 2010. Culex pipiens was strongly suspected as the vector responsible for transmission. In the North center of Morocco, this species has developed resistance to synthetic insecticides. There is an urgent need to find alternatives to the insecticides as natural biocides. Objective. In this work, the insecticidal activity of the extract of the local plant Nerium oleander, which has never been tested before in the North center of Morocco, was studied on larval stages 3 and 4 of Culex pipiens. Methods. Biological tests were realized according to a methodology inspired from standard World Health Organization protocol. The mortality values were determined after 24 h of exposure and LC50 and LC90 values were calculated. Results. The extract had toxic effects on the larvae of culicid mosquitoes. The ethanolic extract of Nerium oleander applied against the larvae of Culex pipiens has given the lethal concentrations LC50 and LC90 in the order of 57.57 mg/mL and 166.35 mg/mL, respectively. Conclusion. This investigation indicates that N. oleander could serve as a potential larvicidal, effective natural biocide against mosquito larvae, particularly Culex pipiens. PMID:26640701

  17. Evaluation of larvicidal activity of biogenic nanoparticles against filariasis causing Culex mosquito vector

    PubMed Central

    Dhanasekaran, Dharumadurai; Thangaraj, Ramasamy

    2013-01-01

    Objective To evaluate the larvicidal activity of biogenic nanoparticles against filariasis causing Culex mosquito vector. Methods The synthesized AgNPs were characterized by UV-vis. spectrum, Fourier transform infrared and X-ray diffraction. Larvae were exposed to varying concentrations of aqueous extract of synthesized AgNPs for 10 min. The different concentrations of 5, 2.5, 1.25, 0.625 and 0.312 mg/L silver nanoparticles were tested against the Culex larvae. Results The mortality rate of Agaricus bisporus biogenic nanoparticles against Culex larvae are 5 mg/L (100%), 2.5 mg/L (81%), 1.25 mg/L (62%), 0.625 mg/L (28%) and 0.312 mg/L (11%). Conclusions These results suggest that the synthesized biogenic AgNPs have the potential to be used as an ideal eco-friendly approach for controlling Culex larvae.

  18. Transposition of the Hermes element in embryos of the vector mosquito, Aedes aegypti.

    PubMed

    Sarkar, A; Yardley, K; Atkinson, P W; James, A A; O'Brochta, D A

    1997-05-01

    Using a plasmid-based transpositional recombination assay in vivo, we have demonstrated that Hermes, a short inverted repeat type transposable element from Musca domestica, can transpose in Aedes aegypti embryos. Hermes transpositions in Ae. aegypti have all the characteristics observed during Hermes transposition in its host M. domestica and in related species. These characteristics include an absolute dependence on the expression of the Hermes transposase and a preference for the integration site GTNCAGAC (P < 0.05). In addition, the rate of Hermes transposition in Ae. aegypti (0.286 transpositions per 10,000 donor plasmids screened) was comparable to that observed in Drosophila melanogaster under similar conditions. These results suggest that Hermes can be developed into a gene vector and genetic engineering tool for Ae. aegypti and related mosquitoes. PMID:9219363

  19. Colonization of a newly constructed urban wetland by mosquitoes in England: implications for nuisance and vector species.

    PubMed

    Medlock, Jolyon M; Vaux, Alexander G C

    2014-12-01

    Urban wetlands are being created in the UK as part of sustainable urban drainage strategies, to create wetland habitats lost during development, to provide a habitat for protected species, and to increase the public's access to 'blue-space' for the improvement of health and well-being. Sewage treatment reedbeds are also being incorporated into newly constructed wetlands to offer an alternative approach to dealing with sewage. This field study aims to provide the first UK evidence of how such newly constructed aquatic habitats are colonized by mosquitoes. A number of new aquatic habitats were surveyed for immature mosquitoes every fortnight over the first two years following wetland construction. The majority of mosquitoes collected were Culex sp. and were significantly associated with the sewage treatment reedbed system, particularly following storm events and sewage inflow. Other more natural aquatic habitats that were subject to cycles of drying and re-wetting contributed the majority of the remaining mosquitoes colonizing. Colonization of permanent habitats was slow, particularly where fluctuations in water levels inhibited emergent vegetation growth. It is recommended that during the planning process for newly constructed wetlands consideration is given on a case-by-case basis to the impact of mosquitoes, either as a cause of nuisance or as potential vectors. Although ornithophagic Culex dominated in this wetland, their potential role as enzootic West Nile virus vectors should not be overlooked. PMID:25424253

  20. Potential mosquito (Diptera:Culicidae) vector of Dirofilaria repens and Dirofilaria immitis in urban areas of Eastern Slovakia.

    PubMed

    Bocková, Eva; Iglódyová, Adriana; Kočišová, Alica

    2015-12-01

    This paper follows the study from 2013 focused on the molecular screening of mosquitoes as vectors of Dirofilaria spp. which provided the information on Aedes vexans as a potential vector of Dirofilaria repens in Slovakia. Current entomological and molecular research indicates that Ae. vexans can participate also in the transmission of Dirofilaria immitis within the region. Using the standard PCR method, we examined 10,500 mosquitoes (Ae. vexans, Ae. rossicus, Anopheles maculipennis s.l., Ochlerotatus sticticus, Ochlerotatus cantans, Ochlerotatus caspius, Culex pipiens/Culex torrentium, Coquillettidia richiardii), collected using CO2-baited traps at six locations in the Eastern Slovakia. Out of 105 pools, 6 pools of mosquitoes Ae. vexans were positive for D. repens DNA (minimum infective rate in Ae. vexas was 6:6.900, i.e. 0.8 per 1.000 mosquitoes), within which 4 were concurrently positive for D. immitis (minimum infective rate in Ae. vexans was 4:6.900 i.e. 0.5 per 1.000 mosquitoes). PMID:26391170

  1. On the Seasonal Occurrence and Abundance of the Zika Virus Vector Mosquito Aedes Aegypti in the Contiguous United States

    PubMed Central

    Monaghan, Andrew J.; Morin, Cory W.; Steinhoff, Daniel F.; Wilhelmi, Olga; Hayden, Mary; Quattrochi, Dale A.; Reiskind, Michael; Lloyd, Alun L.; Smith, Kirk; Schmidt, Chris A.; Scalf, Paige E.; Ernst, Kacey

    2016-01-01

    Introduction: An ongoing Zika virus pandemic in Latin America and the Caribbean has raised concerns that travel-related introduction of Zika virus could initiate local transmission in the United States (U.S.) by its primary vector, the mosquito Aedes aegypti. Methods: We employed meteorologically driven models for 2006-2015 to simulate the potential seasonal abundance of adult Aedes aegypti for fifty cities within or near the margins of its known U.S. range. Mosquito abundance results were analyzed alongside travel and socioeconomic factors that are proxies of viral introduction and vulnerability to human-vector contact.     Results: Meteorological conditions are largely unsuitable for Aedes aegypti over the U.S. during winter months (December-March), except in southern Florida and south Texas where comparatively warm conditions can sustain low-to-moderate potential mosquito abundance. Meteorological conditions are suitable for Aedes aegypti across all fifty cities during peak summer months (July-September), though the mosquito has not been documented in all cities. Simulations indicate the highest mosquito abundance occurs in the Southeast and south Texas where locally acquired cases of Aedes-transmitted viruses have been reported previously. Cities in southern Florida and south Texas are at the nexus of high seasonal suitability for Aedes aegypti and strong potential for travel-related virus introduction. Higher poverty rates in cities along the U.S.-Mexico border may correlate with factors that increase human exposure to Aedes aegypti.     Discussion: Our results can inform baseline risk for local Zika virus transmission in the U.S. and the optimal timing of vector control activities, and underscore the need for enhanced surveillance for Aedes mosquitoes and Aedes-transmitted viruses. PMID:27066299

  2. Bicluster Pattern of Codon Context Usages between Flavivirus and Vector Mosquito Aedes aegypti: Relevance to Infection and Transcriptional Response of Mosquito Genes

    PubMed Central

    Behura, Susanta K.; Severson, David W.

    2014-01-01

    The mosquito Aedes aegypti is the primary vector of dengue virus (DENV) infection in most of the subtropical and tropical countries. Besides DENV, yellow fever virus (YFV) is also transmitted by A. aegypti. Susceptibility of A. aegypti to West Nile virus (WNV) has also been confirmed. Although studies have indicated correlation of codon bias between flaviviridae and their animal/insect hosts, it is not clear if codon sequences have any relation to susceptibility of A. aegypti to DENV, YFV and WNV. In the current study, usages of codon context sequences (codon pairs for neighboring amino acids) of the vector (A. aegypti) genome as well as the flaviviral genomes are investigated. We used bioinformatics methods to quantify codon context bias in a genome-wide manner of A. aegypti as well as DENV, WNV and YFV sequences. Mutual information statistics was applied to perform bicluster analysis of codon context bias between vector and flaviviral sequences. Functional relevance of the bicluster pattern was inferred from published microarray data. Our study shows that codon context bias of DENV, WNV and YFV sequences varies in a bicluster manner with that of specific sets of genes of A. aegypti. Many of these mosquito genes are known to be differentially expressed in response to flaviviral infection suggesting that codon context sequences of A. aegypti and the flaviviruses may play a role in the susceptible interaction between flaviviruses and this mosquito. The bias inusages of codon context sequences likely has a functional association with susceptibility of A. aegypti to flaviviral infection. The results from this study will allow us to conduct hypothesis driven tests to examine the role of codon contexts bias in evolution of vector-virus interactions at the molecular level. PMID:24838953

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

    PubMed Central

    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. 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. PMID:25613346

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Present and future projections of habitat suitability of the Asian tiger mosquito, a vector of viral pathogens, from global climate simulation.

    PubMed

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

    2015-04-01

    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 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 twenty-first 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 approximately 2.4 billion individuals in a land area of nearly 20 million km(2) 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. PMID:25688015

  6. Present and future projections of habitat suitability of the Asian tiger mosquito, a vector of viral pathogens, from global climate simulation

    PubMed Central

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

    2015-01-01

    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 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 twenty-first 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 approximately 2.4 billion individuals in a land area of nearly 20 million km2 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. PMID:25688015

  7. Development of loop-mediated isothermal amplification method for detecting Wuchereria bancrofti DNA in human blood and vector mosquitoes.

    PubMed

    Takagi, Hidekazu; Itoh, Makoto; Kasai, Shinji; Yahathugoda, Thishan C; Weerasooriya, Mirani V; Kimura, Eisaku

    2011-12-01

    We have developed loop-mediated isothermal amplification (LAMP) method to detect Wuchereria bancrofti DNA. The sensitivity and specificity of LAMP method were equivalent to those of PCR method which detects SspI repeat sequence in W. bancrofti genomic DNA: both methods detected one thousandth of W. bancrofti DNA from one microfilaria (Mf), and did not cross-react with DNAs of Brugia malayi, B. pahangi, Dirofilaria immitis, human and Culex quinquefasciatus. We also examined the sensitivity of LAMP using the mimic samples of patient's blood or blood-fed mosquitoes containing one W. bancrofti Mf per sample. The LAMP method was able to detect W. bancrofti DNA in 1000 μl of blood or in a pool of 60 mosquitoes, indicating its usefulness in detecting/monitoring W. bancrofti infection in humans and vector mosquitoes in endemic areas. PMID:21930238

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

    PubMed

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

    2016-03-01

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

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

    PubMed Central

    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

  10. Evaluation of Tribulus terrestris Linn (Zygophyllaceae) acetone extract for larvicidal and repellence activity against mosquito vectors.

    PubMed

    Singh, S P; Raghavendra, K; Singh, R K; Mohanty, S S; Dash, A P

    2008-12-01

    Acetone extracts of leaves and seeds from the Tribulus terrestris (Zygophyllaceae) were tested against mature and immature different mosquito vectors under laboratory condition. The extract showed strong larvicidal, properties 100 per cent mortality in the 3rd-instar larvae was observed in the bioassays with An. culicifacies Giles species A, An. stephensi Liston, Culex quinquefasciatus Say and Aedes aegypti Linn, against 200 ppm of the leaf acetone extract and 100 ppm seed acetone extract. The LC50 values of leaf acetone extract estimated for 3rd-instars An. culicifacies species A, An. stephensi, Cx. quinquefasciatus and Ae. aegypti after 24 hour of exposure were 117, 124, 168 and 185 ppm respectively. The LC50 values of seed acetone extract estimated for 3rd-instars An. culicifacies species A, An. stephensi, Cx. quinquefasciatus and Ae. aegypti after 24 hour of exposure were 100, 72, 91 and 91 ppm respectively. It is confirmed from the LC50 values that the seed acetone extract of T. terrestris is more effective compared to leaf extracts. A significant (P<0.004) higher concentration of acetone extract leaf was required to kill equal number of larvae i.e. against acetone extract of seed. The seed acetone extract showed strong repellent activity against adults mosquitoes. Per cent protection obtained against Anopheles culicifacies species A 100% repellency in 1 h, 6 h; Anopheles stephensi 100% repellency in 0 h, 4 h, 6 h; and Culex quinquefasciatus 100% repellency in 0 h, 2 h, 4 h, at 10% concentration respectively. Against Deet- 2.5% An. culicifacies Giles species A has shown 100% repellency in 1 h, 2 h, 6 h, An. stephensi Liston 99% repellency in 4 h, and Culex quinquefasciatus Say has shown 100% repellency in 1 h, 2 h. PMID:19579717

  11. Larvicidal activity of Saraca indica, Nyctanthes arbor-tristis, and Clitoria ternatea extracts against three mosquito vector species.

    PubMed

    Mathew, Nisha; Anitha, M G; Bala, T S L; Sivakumar, S M; Narmadha, R; Kalyanasundaram, M

    2009-04-01

    Screening of natural products for mosquito larvicidal activity against three major mosquito vectors Aedes aegypti, Culex quinquefasciatus, and Anopheles stephensi resulted in the identification of three potential plant extracts viz., Saraca indica/asoca, Nyctanthes arbor-tristis, and Clitoria ternatea for mosquito larval control. In the case of S. indica/asoca, the petroleum ether extract of the leaves and the chloroform extract of the bark were effective against the larvae of C. quinquefasciatus with respective LC(50) values 228.9 and 291.5 ppm. The LC(50) values of chloroform extract of N. arbor-tristis leaves were 303.2, 518.2, and 420.2 ppm against A. aegypti, A. stephensi, and C. quinquefasciatus, respectively. The methanol and chloroform extracts of flowers of N. arbor-tristis showed larvicidal activity against larvae of A. stephensi with the respective LC(50) values of 244.4 and 747.7 ppm. Among the methanol extracts of C. ternatea leaves, roots, flowers, and seeds, the seed extract was effective against the larvae of all the three species with LC(50) values 65.2, 154.5, and 54.4 ppm, respectively, for A. stephensi, A. aegypti, and C. quinquefasciatus. Among the three plant species studied for mosquito larvicidal activity, C. ternatea was showing the most promising mosquito larvicidal activity. The phytochemical analysis of the promising methanolic extract of the seed extract was positive for carbohydrates, saponins, terpenoids, tannins, and proteins. In conclusion, bioassay-guided fractionation of effective extracts may result in identification of a useful molecule for the control of mosquito vectors. PMID:19039604

  12. Genetic Drift, Purifying Selection and Vector Genotype Shape Dengue Virus Intra-host Genetic Diversity in Mosquitoes

    PubMed Central

    Fontaine, Albin; Ar Gouilh, Meriadeg; Moltini-Conclois, Isabelle

    2016-01-01

    Due to their error-prone replication, RNA viruses typically exist as a diverse population of closely related genomes, which is considered critical for their fitness and adaptive potential. Intra-host demographic fluctuations that stochastically reduce the effective size of viral populations are a challenge to maintaining genetic diversity during systemic host infection. Arthropod-borne viruses (arboviruses) traverse several anatomical barriers during infection of their arthropod vectors that are believed to impose population bottlenecks. These anatomical barriers have been associated with both maintenance of arboviral genetic diversity and alteration of the variant repertoire. Whether these patterns result from stochastic sampling (genetic drift) rather than natural selection, and/or from the influence of vector genetic heterogeneity has not been elucidated. Here, we used deep sequencing of full-length viral genomes to monitor the intra-host evolution of a wild-type dengue virus isolate during infection of several mosquito genetic backgrounds. We estimated a bottleneck size ranging from 5 to 42 founding viral genomes at initial midgut infection, irrespective of mosquito genotype, resulting in stochastic reshuffling of the variant repertoire. The observed level of genetic diversity increased following initial midgut infection but significantly differed between mosquito genetic backgrounds despite a similar initial bottleneck size. Natural selection was predominantly negative (purifying) during viral population expansion. Taken together, our results indicate that dengue virus intra-host genetic diversity in the mosquito vector is shaped by genetic drift and purifying selection, and point to a novel role for vector genetic factors in the genetic breadth of virus populations during infection. Identifying the evolutionary forces acting on arboviral populations within their arthropod vector provides novel insights into arbovirus evolution. PMID:27304978

  13. Genetic Drift, Purifying Selection and Vector Genotype Shape Dengue Virus Intra-host Genetic Diversity in Mosquitoes.

    PubMed

    Lequime, Sebastian; Fontaine, Albin; Ar Gouilh, Meriadeg; Moltini-Conclois, Isabelle; Lambrechts, Louis

    2016-06-01

    Due to their error-prone replication, RNA viruses typically exist as a diverse population of closely related genomes, which is considered critical for their fitness and adaptive potential. Intra-host demographic fluctuations that stochastically reduce the effective size of viral populations are a challenge to maintaining genetic diversity during systemic host infection. Arthropod-borne viruses (arboviruses) traverse several anatomical barriers during infection of their arthropod vectors that are believed to impose population bottlenecks. These anatomical barriers have been associated with both maintenance of arboviral genetic diversity and alteration of the variant repertoire. Whether these patterns result from stochastic sampling (genetic drift) rather than natural selection, and/or from the influence of vector genetic heterogeneity has not been elucidated. Here, we used deep sequencing of full-length viral genomes to monitor the intra-host evolution of a wild-type dengue virus isolate during infection of several mosquito genetic backgrounds. We estimated a bottleneck size ranging from 5 to 42 founding viral genomes at initial midgut infection, irrespective of mosquito genotype, resulting in stochastic reshuffling of the variant repertoire. The observed level of genetic diversity increased following initial midgut infection but significantly differed between mosquito genetic backgrounds despite a similar initial bottleneck size. Natural selection was predominantly negative (purifying) during viral population expansion. Taken together, our results indicate that dengue virus intra-host genetic diversity in the mosquito vector is shaped by genetic drift and purifying selection, and point to a novel role for vector genetic factors in the genetic breadth of virus populations during infection. Identifying the evolutionary forces acting on arboviral populations within their arthropod vector provides novel insights into arbovirus evolution. PMID:27304978

  14. Comparative analysis of midgut bacterial communities of Aedes aegypti mosquito strains varying in vector competence to dengue virus.

    PubMed

    Charan, Shakti S; Pawar, Kiran D; Severson, David W; Patole, Milind S; Shouche, Yogesh S

    2013-07-01

    Differences in midgut bacterial communities of Aedes aegypti, the primary mosquito vector of dengue viruses (DENV), might influence the susceptibility of these mosquitoes to infection by DENV. As a first step toward addressing this hypothesis, comparative analysis of bacterial communities from midguts of mosquito strains with differential genetic susceptibility to DENV was performed. 16S rRNA gene libraries and real-time PCR approaches were used to characterize midgut bacterial community composition and abundance in three Aedes aegypti strains: MOYO, MOYO-R, and MOYO-S. Although Pseudomonas spp.-related clones were predominant across all libraries, some interesting and potentially significant differences were found in midgut bacterial communities among the three strains. Pedobacter sp.- and Janthinobacterium sp.-related phylotypes were identified only in the MOYO-R strain libraries, while Bacillus sp. was detected only in the MOYO-S strain. Rahnella sp. was found in MOYO-R and MOYO strains libraries but was absent in MOYO-S libraries. Both 16S rRNA gene library and real-time PCR approaches confirmed the presence of Pedobacter sp. only in the MOYO-R strain. Further, real-time PCR-based quantification of 16S rRNA gene copies showed bacterial abundance in midguts of the MOYO-R strain mosquitoes to be at least 10-100-folds higher than in the MOYO-S and MOYO strain mosquitoes. Our study identified some putative bacteria with characteristic physiological properties that could affect the infectivity of dengue virus. This analysis represents the first report of comparisons of midgut bacterial communities with respect to refractoriness and susceptibility of Aedes aegypti mosquitoes to DENV and will guide future efforts to address the potential interactive role of midgut bacteria of Aedes aegypti mosquitoes in determining vectorial capacity for DENV. PMID:23636307

  15. Distribution and habitat characterization of the recently introduced invasive mosquito Aedes koreicus [Hulecoeteomyia koreica], a new potential vector and pest in north-eastern Italy

    PubMed Central

    2013-01-01

    Background The container breeding species belonging to the genus Aedes (Meigen) are frequently recorded out of their place of origin. Invasive Aedes species are proven or potential vectors of important Arboviruses and their establishment in new areas pose a threat for human and animal health. A new species of exotic mosquito was recorded in 2011 in north-eastern Italy: Aedes (Finlaya) koreicus [Hulecoeteomyia koreica]. The aim of this study was to characterize the biology, the environment and the current distribution of this mosquito in north-eastern Italy. Morphological details useful to discriminate this species from other invasive Aedes mosquitoes are also given (see Additional files). Methods All possible breeding sites for larval development were monitored. In addition, ovitraps and traps for adults were used to collect eggs and adults. The mosquitoes (larvae and adults) were identified morphologically and molecularly. Environmental data and climatic variables during the period of mosquito activity (from April to October) were considered. Results Aedes koreicus was found in 37 municipalities (39.4%) and was detected in 40.2% of places and in 37.3% of larval habitats monitored, in a range of altitude from 173 to 1250 m.a.s.l.. Garden centres were the most common locations (66.7%), followed by streets/squares (57.1%), private gardens (46.4%) and cemeteries (21.1%) (p < 0.01). The main larval habitats were catch basins (48.5%) and artificial water containers (41.8%). As for Aedes albopictus [Stegomyia albopicta], ovitraps were attractive for adult females resulting in the higher rate of positivity (15/21; 71.4%) among breeding sites. The period of Ae. koreicus activity ranged from March 29 to October 29. Conclusion The species is clearly established in the area and is now overlapping with other vectors such as Ae. albopictus and colonizing areas over 800 m.a.s.l, not yet or sporadically reached by the tiger mosquito. The data collected are essential to

  16. Aquaporin water channel AgAQP1 in the malaria vector mosquito Anopheles gambiae during blood feeding and humidity adaptation

    PubMed Central

    Liu, Kun; Tsujimoto, Hitoshi; Cha, Sung-Jae; Agre, Peter; Rasgon, Jason L.

    2011-01-01

    Altered patterns of malaria endemicity reflect, in part, changes in feeding behavior and climate adaptation of mosquito vectors. Aquaporin (AQP) water channels are found throughout nature and confer high-capacity water flow through cell membranes. The genome of the major malaria vector mosquito Anopheles gambiae contains at least seven putative AQP sequences. Anticipating that transmembrane water movements are important during the life cycle of A. gambiae, we identified and characterized the A. gambiae aquaporin 1 (AgAQP1) protein that is homologous to AQPs known in humans, Drosophila, and sap-sucking insects. When expressed in Xenopus laevis oocytes, AgAQP1 transports water but not glycerol. Similar to mammalian AQPs, water permeation of AgAQP1 is inhibited by HgCl2 and tetraethylammonium, with Tyr185 conferring tetraethylammonium sensitivity. AgAQP1 is more highly expressed in adult female A. gambiae mosquitoes than in males. Expression is high in gut, ovaries, and Malpighian tubules where immunofluorescence microscopy reveals that AgAQP1 resides in stellate cells but not principal cells. AgAQP1 expression is up-regulated in fat body and ovary by blood feeding but not by sugar feeding, and it is reduced by exposure to a dehydrating environment (42% relative humidity). RNA interference reduces AgAQP1 mRNA and protein levels. In a desiccating environment (<20% relative humidity), mosquitoes with reduced AgAQP1 protein survive significantly longer than controls. These studies support a role for AgAQP1 in water homeostasis during blood feeding and humidity adaptation of A. gambiae, a major mosquito vector of human malaria in sub-Saharan Africa. PMID:21444767

  17. Adulticidal properties of synthesized silver nanoparticles using leaf extracts of Feronia elephantum (Rutaceae) against filariasis, malaria, and dengue vector mosquitoes.

    PubMed

    Veerakumar, Kaliyan; Govindarajan, Marimuthu

    2014-11-01

    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 alternative sources of mosquito control agents because they constitute a rich source of bioactive compounds that are biodegradable into nontoxic products and potentially suitable for use to control mosquitoes. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. 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 Feronia elephantum plant leaf extract against adults of Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus was determined. The range of concentrations of synthesized AgNPs (8, 16, 24, 32, and 40 μg mL(-1)) and aqueous leaf extract (40, 80, 120, 160, and 200 μg mL(-1)) were tested against the adults of A. stephensi, A. aegypti, and C. quinquefasciatus. Adults were exposed to varying concentrations of aqueous crude extract and synthesized AgNPs for 24 h. Considerable mortality was evident after the treatment of F. elephantum for all three important vector mosquitoes. The synthesized AgNPs from F. elephantum were highly toxic than crude leaf aqueous extract to three important vector mosquito species. The results were recorded from UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy analysis (EDX), and transmission electron microscopy (TEM). Synthesized AgNPs against the vector mosquitoes A. stephensi, A. aegypti, and C. quinquefasciatus had the following lethal dose (LD)₅₀ and LD₉₀ values: A. stephensi had LD₅₀ and LD₉₀ values of 18

  18. A CRISPR-Cas9 Gene Drive System Targeting Female Reproduction in the Malaria Mosquito vector Anopheles gambiae

    PubMed Central

    Hammond, Andrew; Galizi, Roberto; Kyrou, Kyros; Simoni, Alekos; Siniscalchi, Carla; Katsanos, Dimitris; Gribble, Matthew; Baker, Dean; Marois, Eric; Russell, Steven; Burt, Austin; Windbichler, Nikolai; Crisanti, Andrea; Nolan, Tony

    2016-01-01

    Gene-drive systems that enable super-Mendelian inheritance of a transgene have the potential to modify insect populations over a timeframe of a few years [AU please provide a real estimate, this seems vague]. We describe CRISPR-Cas9 endonuclease constructs that function as gene-drive systems in Anopheles gambiae, the main vector for malaria [AU:OK?]. We identified three genes (AGAP005958, AGAP011377 and AGAP007280) that confer a recessive female sterility phenotype upon disruption, and inserted into each locus CRISPR-Cas9 gene-drive constructs designed to target and edit each gene [AU:OK?]. For each locus targeted we observed strong gene drive at the molecular level, with transmission rates to progeny of 91 to 99.6%. Population modelling and cage experiments indicate that a CRISPR-Cas9 construct targeting one of these loci, AGAP007280, meets the minimum requirement for a gene drive targeting female reproduction in an insect population. These findings could expedite the development of gene drives to control suppress mosquito populations to levels that do not support malaria transmission. PMID:26641531

  19. A CRISPR-Cas9 gene drive system targeting female reproduction in the malaria mosquito vector Anopheles gambiae.

    PubMed

    Hammond, Andrew; Galizi, Roberto; Kyrou, Kyros; Simoni, Alekos; Siniscalchi, Carla; Katsanos, Dimitris; Gribble, Matthew; Baker, Dean; Marois, Eric; Russell, Steven; Burt, Austin; Windbichler, Nikolai; Crisanti, Andrea; Nolan, Tony

    2016-01-01

    Gene drive systems that enable super-Mendelian inheritance of a transgene have the potential to modify insect populations over a timeframe of a few years. We describe CRISPR-Cas9 endonuclease constructs that function as gene drive systems in Anopheles gambiae, the main vector for malaria. We identified three genes (AGAP005958, AGAP011377 and AGAP007280) that confer a recessive female-sterility phenotype upon disruption, and inserted into each locus CRISPR-Cas9 gene drive constructs designed to target and edit each gene. For each targeted locus we observed a strong gene drive at the molecular level, with transmission rates to progeny of 91.4 to 99.6%. Population modeling and cage experiments indicate that a CRISPR-Cas9 construct targeting one of these loci, AGAP007280, meets the minimum requirement for a gene drive targeting female reproduction in an insect population. These findings could expedite the development of gene drives to suppress mosquito populations to levels that do not support malaria transmission. PMID:26641531

  20. Suboptimal Larval Habitats Modulate Oviposition of the Malaria Vector Mosquito Anopheles coluzzii

    PubMed Central

    Suh, Eunho; Choe, Dong-Hwan; Saveer, Ahmed M.; Zwiebel, Laurence J.

    2016-01-01

    Selection of oviposition sites by gravid females is a critical behavioral step in the reproductive cycle of Anopheles coluzzii, which is one of the principal Afrotropical malaria vector mosquitoes. Several studies suggest this decision is mediated by semiochemicals associated with potential oviposition sites. To better understand the chemosensory basis of this behavior and identify compounds that can modulate oviposition, we examined the generally held hypothesis that suboptimal larval habitats give rise to semiochemicals that negatively influence the oviposition preference of gravid females. Dual-choice bioassays indicated that oviposition sites conditioned in this manner do indeed foster significant and concentration dependent aversive effects on the oviposition site selection of gravid females. Headspace analyses derived from aversive habitats consistently noted the presence of dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS) and 6-methyl-5-hepten-2-one (sulcatone) each of which unitarily affected An. coluzzii oviposition preference. Electrophysiological assays across the antennae, maxillary palp, and labellum of gravid An. coluzzii revealed differential responses to these semiochemicals. Taken together, these findings validate the hypothesis in question and suggest that suboptimal environments for An. coluzzii larval development results in the release of DMDS, DMTS and sulcatone that impact the response valence of gravid females. PMID:26900947

  1. Effect of Polygonum hydropiper L. against dengue vector mosquito Aedes albopictus L.

    PubMed

    Maheswaran, Rajan; Ignacimuthu, Savarimuthu

    2014-09-01

    The present study aimed to evaluate the essential oil and an isolated compound from the leaves of Polygonum hydropiper L. against dengue vector mosquito Aedes albopictus L. The plant material was macerated and steam distilled using clavenger apparatus for oil extraction. The essential oil was tested at different concentrations of 100, 50, 25, 12.5 and 6.25 ppm concentrations against the larvae of Ae. albopictus. The isolated compound was tested for larvicidal, ovicidal, repellent, oviposition deterrent and adulticidal activities at 10, 5, 2.5, 1.25 and 0.625 ppm concentrations. The essential oil exhibited LC₅₀ values of 194.63 and 199.65 and confertifolin exhibited LC₅₀ values of 2.02 and 3.16 against the second and fourth instar larvae of Ae. albopictus, respectively. The ovicidal activity of 100% on 0- to 6-h-old eggs, repellent activity of 320.6 min, oviposition deterrent activity of 98.51% and adulticidal activity of 100% at 10 ppm concentration of confertifolin were recorded. No mortality of was observed in negative control. To the best of our knowledge, this is the first report on the potential mosquitocidal activities of confertifolin against Ae. albopictus. PMID:25033815

  2. Influence of IGR treatment on oviposition of three species of vector mosquitos at sublethal concentrations.

    PubMed

    Vasuki, V

    1999-03-01

    Sublethal effect of hexaflumuron, an insect growth regulator (IGR), on the oviposition of three species of vector mosquitos. Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi was studied. Significant reduction in oviposition was observed in the females of the above three species derived from fourth instar larvae and pupae exposed to sublethal (EI5 and EI50) doses. The reduction in egg laying is proportional to the dose of exposure and was found to be about twice higher in females of three species exposed to EI50 dose than those exposed to EI5 dose. Among the three species exposed at larval and pupal stages, Ae. aegypti showed maximum reduction in egg laying (29.3-46.6%). Blood feeding was also reduced in females exposed to EI50 dose at larval stage and a positive correlation was demonstrated between the quantity of blood meal taken and the proportion of eggs laid. Significant reduction in the quantum of blood ingested by the treated females may be responsible for the reduced egg laying. PMID:10695811

  3. An Integrated Genetic Map of the African Human Malaria Vector Mosquito, Anopheles Gambiae

    PubMed Central

    Zheng, L.; Benedict, M. Q.; Cornel, A. J.; Collins, F. H.; Kafatos, F. C.

    1996-01-01

    We present a genetic map based on microsatellite polymorphisms for the African human malaria vector, Anopheles gambiae. Polymorphisms in laboratory strains were detected for 89% of the tested microsatellite markers. Genotyping was performed for individual mosquitoes from 13 backcross families that included 679 progeny. Three linkage groups were identified, corresponding to the three chromosomes. We added 22 new markers to the existing X chromosome map, for a total of 46 microsatellite markers spanning a distance of 48.9 cM. The second chromosome has 57 and the third 28 microsatellite markers spanning a distance of 72.4 and 93.7 cM, respectively. The overall average distance between markers is 1.6 cM (or 1.1, 1.2, and 3.2 cM for the X, second, and third chromosomes, respectively). In addition to the 131 microsatellite markers, the current map also includes a biochemical selectable marker, Dieldrin resistance (Dl), on the second chromosome and five visible markers, pink-eye (p) and white (w) on the X, collarless (c) and lunate (lu) on the second, and red-eye (r) on the third. The cytogenetic locations on the nurse cell polytene chromosomes have been determined for 47 markers, making this map an integrated tool for cytogenetic, genetic, and molecular analysis. PMID:8725240

  4. Comparative Genomic Analysis of Malaria Mosquito Vector-Associated Novel Pathogen Elizabethkingia anophelis

    PubMed Central

    Teo, Jeanette; Tan, Sean Yang-Yi; Liu, Yang; Tay, Martin; Ding, Yichen; Li, Yingying; Kjelleberg, Staffan; Givskov, Michael; Lin, Raymond T.P.; Yang, Liang

    2014-01-01

    Acquisition of Elizabethkingia infections in intensive care units (ICUs) has risen in the past decade. Treatment of Elizabethkingia infections is challenging due to the lack of effective therapeutic regimens, leading to a high mortality rate. Elizabethkingia infections have long been attributed to Elizabethkingia meningoseptica. Recently, we used whole-genome sequencing to reveal that E. anophelis is the pathogenic agent for an Elizabethkingia outbreak at two ICUs. We performed comparative genomic analysis of seven hospital-isolated E. anophelis strains with five available Elizabethkingia spp. genomes deposited in the National Center for Biotechnology Information Database. A pan-genomic approach was applied to identify the core- and pan-genome for the Elizabethkingia genus. We showed that unlike the hospital-isolated pathogen E. meningoseptica ATCC 12535 strain, the hospital-isolated E. anophelis strains have genome content and organization similar to the E. anophelis Ag1 and R26 strains isolated from the midgut microbiota of the malaria mosquito vector Anopheles gambiae. Both the core- and accessory genomes of Elizabethkingia spp. possess genes conferring antibiotic resistance and virulence. Our study highlights that E. anophelis is an emerging bacterial pathogen for hospital environments. PMID:24803570

  5. First report in italy of the exotic mosquito species Aedes (Finlaya) koreicus, a potential vector of arboviruses and filariae

    PubMed Central

    2011-01-01

    Background In the Veneto region (north-eastern Italy) an entomological surveillance system has been implemented since the introduction of the Asian tiger mosquito (Aedes albopictus) in 1991. During the routine monitoring activity in a tiger mosquito-free area, an unexpected mosquito was noticed, which clearly did not belong to the recorded Italian fauna. Findings At the end of May 2011, twelve larvae and pupae were collected in a small village in Belluno province (Veneto region) from a single manhole. Ten adults reared in the laboratory were morphologically and genetically identified as Aedes (Finlaya) koreicus (Edwards, 1917), a species native to Southeast Asia. The subsequent investigations carried out in the following months in the same village provided evidence that this species had become established locally. Entomological and epidemiological investigations are currently ongoing in the surrounding area, to verify the eventual extension of the species outside the village and to trace back the route of entry into Italy. Conclusions This is the first report in Italy of the introduction of the exotic mosquito Ae. koreicus. This species has been shown experimentally to be competent in the transmission of the Japanese encephalitis virus and of the dog heartworm Dirofilaria immitis and is considered a potential vector of other arboviruses. Thus, the establishment of this species may increase the current risk or pose new potential threats, for human and animal health. This finding considerably complicates the entomological monitoring of the Asian tiger mosquito Ae. albopictus in Italy and stresses the importance of implementing the entomological surveillance for the early detection of and the rapid response against invasive mosquito species. PMID:21951867

  6. 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).

    PubMed

    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

  7. Sustainable urban development and human health: septic tank as a major breeding habitat of mosquito vectors of human diseases in south-eastern Nigeria.

    PubMed

    Nwoke, B E; Nduka, F O; Okereke, O M; Ehighibe, O C

    1993-02-01

    Septic tank mosquitoes in Abia State University Okigwe, south-eastern Nigeria were studied using exit traps between November 1988 and April 1989. The results were revealing and striking. Apart from the common septic tank mosquitoes, Culex p. quinquefasciatus, Cu. cinereus and Aedes aegypti, which have been previously commonly found breeding in ammonia and nitrate-rich waters of latrines and septic tanks, the other species, Cu. horridus, Cu. tigripes and Aedes vittatus, have not been commonly reported as colonizing septic tanks in Nigeria. Three out of these six mosquito species observed are vectors of human diseases: Aedes aegypti and Aedes vittatus are vectors of Yellow fever and Cu. p. quinquefasciatus is a potential vector of Bancroftian filariasis and a world-wide vector of various arboviruses. The fact that these mosquito vectors are able to breed in highly polluted waters of septic tanks during the harsh dry months when most surface water bodies are dry is epidemiologically important. The breeding of these mosquito vectors of human diseases around human dwellings indicates an intense man-vector contact creating a high level risk to the crowded urban population. The public health implications of this urbanization/modernization problem and solutions are discussed. PMID:8508215

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

    PubMed

    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. PMID:22841800

  9. Spatially explicit model of transposon-based genetic drive mechanisms for displacing fluctuating populations of anopheline vector mosquitoes.

    PubMed

    Kiszewski, A E; Spielman, A

    1998-07-01

    To evaluate the prospect of transposon-based genetic drive mechanisms for replacing African vectors of malaria with nonvector anopheline mosquitoes, we developed a spatially explicit simulation model that determined the likelihood that released transgenic mosquitoes may proceed to fixation or extinction under diverse conditions. We compared the effect on fixation of long breeding seasons with relatively subtle population fluctuations to short breeding seasons with severe bottlenecks. Assuming 100% transposition efficiency among heterozygotes with fitness varying between 50 and 100% of that of wild-type mosquitoes, we simulated releases of 1, 10, 50, 90, and 99% of transposon-bearers in relation to wild mosquitoes as well as 1 and 10% releases that were repeated annually. We also evaluated diverse patterns of release including linear, marginal, focused, and scattered distribution. Random dispersal provided the most rapid fixation of transposons within populations. More massive releases allowed longer persistence of transposon-bearers but did not promote fixation, especially when breeding seasons were long. Relative fitness of transposon-bearers, however, proved more powerful than pattern or number of releases in determining whether a construct will become fixed or extinct. Even when fitness approaches that of the wild-type, fixation of a construct may require 150 generations or more. PMID:9701949

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

    PubMed

    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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  12. Sialic Acid Expression in the Mosquito Aedes aegypti and Its Possible Role in Dengue Virus-Vector Interactions

    PubMed Central

    Cime-Castillo, Jorge; Delannoy, Philippe; Mendoza-Hernández, Guillermo; Monroy-Martínez, Verónica; Lanz-Mendoza, Humberto; Hernández-Hernández, Fidel de la Cruz; Cabello-Gutiérrez, Carlos; Ruiz-Ordaz, Blanca H.

    2015-01-01

    Dengue fever (DF) is the most prevalent arthropod-borne viral disease which affects humans. DF is caused by the four dengue virus (DENV) serotypes, which are transmitted to the host by the mosquito Aedes aegypti that has key roles in DENV infection, replication, and viral transmission (vector competence). Mosquito saliva also plays an important role during DENV transmission. In this study, we detected the presence of sialic acid (Sia) in Aedes aegypti tissues, which may have an important role during DENV-vector competence. We also identified genome sequences encoding enzymes involved in Sia pathways. The cDNA for Aedes aegypti CMP-Sia synthase (CSAS) was amplified, cloned, and functionally evaluated via the complementation of LEC29.Lec32 CSAS-deficient CHO cells. AedesCSAS-transfected LEC29.Lec32 cells were able to express Sia moieties on the cell surface. Sequences related to α-2,6-sialyltransferase were detected in the Aedes aegypti genome. Likewise, we identified Sia-α-2,6-DENV interactions in different mosquito tissues. In addition, we evaluated the possible role of sialylated molecules in a salivary gland extract during DENV internalization in mammalian cells. The knowledge of early DENV-host interactions could facilitate a better understanding of viral tropism and pathogenesis to allow the development of new strategies for controlling DENV transmission. PMID:25874215

  13. Sialic acid expression in the mosquito Aedes aegypti and its possible role in dengue virus-vector interactions.

    PubMed

    Cime-Castillo, Jorge; Delannoy, Philippe; Mendoza-Hernández, Guillermo; Monroy-Martínez, Verónica; Harduin-Lepers, Anne; Lanz-Mendoza, Humberto; Hernández-Hernández, Fidel de la Cruz; Zenteno, Edgar; Cabello-Gutiérrez, Carlos; Ruiz-Ordaz, Blanca H

    2015-01-01

    Dengue fever (DF) is the most prevalent arthropod-borne viral disease which affects humans. DF is caused by the four dengue virus (DENV) serotypes, which are transmitted to the host by the mosquito Aedes aegypti that has key roles in DENV infection, replication, and viral transmission (vector competence). Mosquito saliva also plays an important role during DENV transmission. In this study, we detected the presence of sialic acid (Sia) in Aedes aegypti tissues, which may have an important role during DENV-vector competence. We also identified genome sequences encoding enzymes involved in Sia pathways. The cDNA for Aedes aegypti CMP-Sia synthase (CSAS) was amplified, cloned, and functionally evaluated via the complementation of LEC29.Lec32 CSAS-deficient CHO cells. AedesCSAS-transfected LEC29.Lec32 cells were able to express Sia moieties on the cell surface. Sequences related to α-2,6-sialyltransferase were detected in the Aedes aegypti genome. Likewise, we identified Sia-α-2,6-DENV interactions in different mosquito tissues. In addition, we evaluated the possible role of sialylated molecules in a salivary gland extract during DENV internalization in mammalian cells. The knowledge of early DENV-host interactions could facilitate a better understanding of viral tropism and pathogenesis to allow the development of new strategies for controlling DENV transmission. PMID:25874215

  14. Co-occurrence Patterns of the Dengue Vector Aedes aegypti and Aedes mediovitattus, a Dengue Competent Mosquito in Puerto Rico

    PubMed Central

    Little, Eliza; Barrera, Roberto; Seto, Karen C.; Diuk-Wasser, Maria

    2015-01-01

    Aedes aegypti is implicated in dengue transmission in tropical and subtropical urban areas around the world. Ae. aegypti populations are controlled through integrative vector management. However, the efficacy of vector control may be undermined by the presence of alternative, competent species. In Puerto Rico, a native mosquito, Ae. mediovittatus, is a competent dengue vector in laboratory settings and spatially overlaps with Ae. aegypti. It has been proposed that Ae. mediovittatus may act as a dengue reservoir during inter-epidemic periods, perpetuating endemic dengue transmission in rural Puerto Rico. Dengue transmission dynamics may therefore be influenced by the spatial overlap of Ae. mediovittatus, Ae. aegypti, dengue viruses, and humans. We take a landscape epidemiology approach to examine the association between landscape composition and configuration and the distribution of each of these Aedes species and their co-occurrence. We used remotely sensed imagery from a newly launched satellite to map landscape features at very high spatial resolution. We found that the distribution of Ae. aegypti is positively predicted by urban density and by the number of tree patches, Ae. mediovittatus is positively predicted by the number of tree patches, but negatively predicted by large contiguous urban areas, and both species are predicted by urban density and the number of tree patches. This analysis provides evidence that landscape composition and configuration is a surrogate for mosquito community composition, and suggests that mapping landscape structure can be used to inform vector control efforts as well as to inform urban planning. PMID:21989642

  15. Artemisinin-resistant Plasmodium falciparum clinical isolates can infect diverse mosquito vectors of Southeast Asia and Africa

    PubMed Central

    St. Laurent, Brandyce; Miller, Becky; Burton, Timothy A.; Amaratunga, Chanaki; Men, Sary; Sovannaroth, Siv; Fay, Michael P.; Miotto, Olivo; Gwadz, Robert W.; Anderson, Jennifer M.; Fairhurst, Rick M.

    2015-01-01

    Artemisinin-resistant Plasmodium falciparum parasites are rapidly spreading in Southeast Asia, yet nothing is known about their transmission. This knowledge gap and the possibility that these parasites will spread to Africa endanger global efforts to eliminate malaria. Here we produce gametocytes from parasite clinical isolates that displayed artemisinin resistance in patients and in vitro, and use them to infect native and non-native mosquito vectors. We show that contemporary artemisinin-resistant isolates from Cambodia develop and produce sporozoites in two Southeast Asian vectors, Anopheles dirus and Anopheles minimus, and the major African vector, Anopheles coluzzii (formerly Anopheles gambiae M). The ability of artemisinin-resistant parasites to infect such highly diverse Anopheles species, combined with their higher gametocyte prevalence in patients, may explain the rapid expansion of these parasites in Cambodia and neighbouring countries, and further compromise efforts to prevent their global spread. PMID:26485448

  16. Artemisinin-resistant Plasmodium falciparum clinical isolates can infect diverse mosquito vectors of Southeast Asia and Africa.

    PubMed

    St Laurent, Brandyce; Miller, Becky; Burton, Timothy A; Amaratunga, Chanaki; Men, Sary; Sovannaroth, Siv; Fay, Michael P; Miotto, Olivo; Gwadz, Robert W; Anderson, Jennifer M; Fairhurst, Rick M

    2015-01-01

    Artemisinin-resistant Plasmodium falciparum parasites are rapidly spreading in Southeast Asia, yet nothing is known about their transmission. This knowledge gap and the possibility that these parasites will spread to Africa endanger global efforts to eliminate malaria. Here we produce gametocytes from parasite clinical isolates that displayed artemisinin resistance in patients and in vitro, and use them to infect native and non-native mosquito vectors. We show that contemporary artemisinin-resistant isolates from Cambodia develop and produce sporozoites in two Southeast Asian vectors, Anopheles dirus and Anopheles minimus, and the major African vector, Anopheles coluzzii (formerly Anopheles gambiae M). The ability of artemisinin-resistant parasites to infect such highly diverse Anopheles species, combined with their higher gametocyte prevalence in patients, may explain the rapid expansion of these parasites in Cambodia and neighbouring countries, and further compromise efforts to prevent their global spread. PMID:26485448

  17. 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.

    PubMed

    Siptroth, Stephen M; Shanahan, Richard P

    2011-12-01

    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. PMID:23856372

  18. Chromobacterium Csp_P Reduces Malaria and Dengue Infection in Vector Mosquitoes and Has Entomopathogenic and In Vitro Anti-pathogen Activities

    PubMed Central

    Bahia, Ana C.; Saraiva, Raul G.; Dong, Yuemei; Kang, Seokyoung; Tripathi, Abhai; Mlambo, Godfree; Dimopoulos, George

    2014-01-01

    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. PMID:25340821

  19. Pupicidal and repellent activities of Pogostemon cablin essential oil chemical compounds against medically important human vector mosquitoes

    PubMed Central

    Gokulakrishnan, J; Kuppusamy, Elumalai; Shanmugam, Dhanasekaran; Appavu, Anandan; Kaliyamoorthi, Krishnappa

    2013-01-01

    Objective To determine the repellent and pupicidal activities of Pogostemon cablin (P. cablin) chemical compositions were assayed for their toxicity against selected important vector mosquitoes, viz., Aedes aegypti (Ae. aegypti), Anopheles stephensi (An. stephensi) and Culex quinquefasciatus (Cx. quinquefasciatus) (Diptera: Culicidae). Methods The plants dry aerial parts were subjected to hydrodistillation using a modified Clevenger-type apparatus. The composition of the essential oil was analyzed by Gas Chromatography (GC) and GC mass spectrophotometry. Evaluation was carried out in a net cage (45 cm×30 cm×45 cm) containing 100 blood starved female mosquitoes and were assayed in the laboratory condition by using the protocol of WHO 2010. The repellent activity of P. cablin chemical compositions at concentration of 2mg/cm2were applied on skin of fore arm in man and exposed against adult female mosquitoes. The pupicidal activity was determined against selected important vector mosquitoes to concentration of 100 mg/L and mortality of each pupa was recorded after 24 h of exposure to the compounds. Results Chemical constituents of 15 compounds were identified in the oil of P.cablin compounds representing to 98.96%. The major components in essential oil were â-patchoulene, á-guaiene, ã-patchoulene, á-bulnesene and patchouli alcohol. The repellent activity of patchouli alcohol compound was found to be most effective for repellent activity and 2 mg/cm2 concentration provided 100% protection up to 280 min against Ae. aegypti, An. stephensi and Cx. quinquefasciatus, respectively. Similarly, pupae exposed to 100 mg/L concentrations of P. cablin chemical compositions. Among five compounds tested patchouli alcoholwas found to be most effective for pupicidal activity provided 28.44, 26.28 and 25.36 against Ae.aegypti, An.stephensi and Cx. quinquefasciatus, respectively. The percent adult emergence was inversely proportional to the concentration of compounds and directly

  20. Mosquitocidal properties of IgG targeting the glutamate-gated chloride channel in three mosquito disease vectors (Diptera: Culicidae)

    PubMed Central

    Meyers, Jacob I.; Gray, Meg; Foy, Brian D.

    2015-01-01

    ABSTRACT The glutamate-gated chloride channel (GluCl) is a highly sensitive insecticide target of the avermectin class of insecticides. As an alternative to using chemical insecticides to kill mosquitoes, we tested the effects of purified immunoglobulin G (IgG) targeting the extracellular domain of GluCl from Anopheles gambiae (AgGluCl) on the survivorship of three key mosquito disease vectors: Anopheles gambiae s.s., Aedes aegypti and Culex tarsalis. When administered through a single blood meal, anti-AgGluCl IgG reduced the survivorship of A. gambiae in a dose-dependent manner (LC50: 2.82 mg ml−1, range 2.68–2.96 mg ml−1) but not A. aegypti or C. tarsalis. We previously demonstrated that AgGluCl is only located in tissues of the head and thorax of A. gambiae. To verify that AgGluCl IgG is affecting target antigens found outside the midgut, we injected it directly into the hemocoel via intrathoracic injection. A single, physiologically relevant concentration of anti-AgGluCl IgG injected into the hemocoel equally reduced mosquito survivorship of all three species. To test whether anti-AgGluCl IgG was entering the hemocoel of each of these mosquitoes, we fed mosquitoes a blood meal containing anti-AgGluCl IgG and subsequently extracted their hemolymph. We only detected IgG in the hemolymph of A. gambiae, suggesting that resistance of A. aegypti and C. tarsalis to anti-AgGluCl IgG found in blood meals is due to deficient IgG translocation across the midgut. We predicted that anti-AgGluCl IgG's mode of action is by antagonizing GluCl activity. To test this hypothesis, we fed A. gambiae blood meals containing anti-AgGluCl IgG and the GluCl agonist ivermectin (IVM). Anti-AgGluCl IgG attenuated the mosquitocidal effects of IVM, suggesting that anti-AgGluCl IgG antagonizes IVM-induced activation of GluCl. Lastly, we stained adult, female A. aegypti and C. tarsalis for GluCl expression. Neuronal GluCl expression in these mosquitoes was similar to previously

  1. Field Detection of Tembusu Virus in Western Thailand by RT-PCR and Vector Competence Determination of Select Culex Mosquitoes for Transmission of the Virus

    PubMed Central

    O'Guinn, Monica L.; Turell, Michael J.; Kengluecha, Ampornpan; Jaichapor, Boonsong; Kankaew, Prasan; Miller, R. Scott; Endy, Timothy P.; Jones, James W.; Coleman, Russell E.; Lee, John S.

    2013-01-01

    Tembusu virus (TMUV; Ntaya serocomplex) was detected in two pools of mosquitoes captured near Sangkhlaburi, Thailand, as well as from sera from sentinel ducks from the same area. Although TMUV has been isolated from several mosquito species in Asia, no studies have ever shown competent vectors for this virus. Therefore, we allowed mosquitoes captured near Sangkhlaburi to feed on young chickens that had been infected with TMUV. These mosquitoes were tested approximately 2 weeks later to determine infection, dissemination, and transmission rates. Culex vishnui developed high viral titers after feeding on TMUV-infected chicks and readily transmitted virus to naïve chickens. In contrast, Cx. fuscocephala seemed less susceptible to infection, and more importantly, zero of five fuscocephala with a disseminated infection transmitted virus by bite, indicating a salivary gland barrier. These results provide evidence for the involvement of Culex mosquitoes in the transmission of TMUV in the environment. PMID:24043687

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

    PubMed

    Mysore, Keshava; Sun, Longhua; Tomchaney, Michael; Sullivan, Gwyneth; Adams, Haley; Piscoya, Andres S; Severson, David W; Syed, Zainulabeuddin; Duman-Scheel, Molly

    2015-11-01

    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. PMID:26544686

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

    PubMed Central

    Mysore, Keshava; Sun, Longhua; Tomchaney, Michael; Sullivan, Gwyneth; Adams, Haley; Piscoya, Andres S.; Severson, David W.; Syed, Zainulabeuddin; Duman-Scheel, Molly

    2015-01-01

    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. PMID:26544686

  4. Landscape factors influencing the spatial distribution and abundance of mosquito vector Culex quinquefasciatus (Diptera: Culicidae) in a mixed residential-agricultural community in Hawai'i

    USGS Publications Warehouse

    Reiter, M.E.; Lapointe, D.A.

    2007-01-01

    Mosquito-borne avian diseases, principally avian malaria (Plasmodium relictum Grassi and Feletti) and avian pox (Avipoxvirus sp.) have been implicated as the key limiting factor associated with recent declines of endemic avifauna in the Hawaiian Island archipelago. We present data on the relative abundance, infection status, and spatial distribution of the primary mosquito vector Culex quinquefasciatus Say (Diptera: Culicidae) across a mixed, residential-agricultural community adjacent to Hawai'i Volcanoes National Park on Hawai'i Island. We modeled the effect of agriculture and forest fragmentation in determining relative abundance of adult Cx. quinquefasciatus in Volcano Village, and we implement our statistical model in a geographic information system to generate a probability of mosquito capture prediction surface for the study area. Our model was based on biweekly captures of adult mosquitoes from 20 locations within Volcano Village from October 2001 to April 2003. We used mixed effects logistic regression to model the probability of capturing a mosquito, and we developed a set of 17 competing models a priori to specifically evaluate the effect of agriculture and fragmentation (i.e., residential landscapes) at two spatial scales. In total, 2,126 mosquitoes were captured in CO 2-baited traps with an average probability of 0.27 (SE = 0.10) of capturing one or more mosquitoes per trap night. Twelve percent of mosquitoes captured were infected with P. relictum. Our data indicate that agricultural lands and forest fragmentation significantly increase the probability of mosquito capture. The prediction surface identified areas along the Hawai'i Volcanoes National Park boundary that may have high relative abundance of the vector. Our data document the potential of avian malaria transmission in residential-agricultural landscapes and support the need for vector management that extends beyond reserve boundaries and considers a reserve's spatial position in a highly

  5. Aedes aegypti (Diptera: Culicidae) in Mauritania: First Report on the Presence of the Arbovirus Mosquito Vector in Nouakchott.

    PubMed

    Mint Lekweiry, Khadijetou; Ould Ahmedou Salem, Mohamed Salem; Ould Brahim, Khyarhoum; Ould Lemrabott, Mohamed Aly; Brengues, Cécile; Faye, Ousmane; Simard, Frédéric; Ould Mohamed Salem Boukhary, Ali

    2015-07-01

    Aedes aegypti L. (Diptera: Culicidae) is a major vector of yellow fever, dengue, and chikungunya viruses throughout tropical and subtropical areas of the world. Although the southernmost part of Mauritania along the Senegal river has long been recognized at risk of yellow fever transmission, Aedes spp. mosquitoes had never been reported northwards in Mauritania. Here, we report the first observation of Aedes aegypti aegypti (L.) and Aedes (Ochlerotatus) caspius (Pallas, 1771) in the capital city, Nouakchott. We describe the development sites in which larvae of the two species were found, drawing attention to the risk for emergence of arbovirus transmission in the city. PMID:26335483

  6. Neural responses to one- and two-tone stimuli in the hearing organ of the dengue vector mosquito

    PubMed Central

    Arthur, Ben J.; Wyttenbach, Robert A.; Harrington, Laura C.; Hoy, Ronald R.

    2010-01-01

    SUMMARY Recent studies demonstrate that mosquitoes listen to each other's wing beats just prior to mating in flight. Field potentials from sound-transducing neurons in the antennae contain both sustained and oscillatory components to pure and paired tone stimuli. Described here is a direct comparison of these two types of response in the dengue vector mosquito, Aedes aegypti. Across a wide range of frequencies and intensities, sustained responses to one- and two-tone stimuli are about equal in magnitude to oscillatory responses to the beats produced by two-tone stimuli. All of these responses are much larger than the oscillatory responses to one-tone stimuli. Similarly, the frequency range extends up to at least the fifth harmonic of the male flight tone for sustained responses to one- and two-tone stimuli and oscillatory responses at the beat frequency of two-tone stimuli, whereas the range of oscillatory response to a one-tone stimulus is limited to, at most, the third harmonic. Thresholds near the fundamental of the flight tone are lower for oscillatory responses than for sustained deflections, lower for males than for females, and within the behaviorally relevant range. A simple model of the transduction process can qualitatively account for both oscillatory and sustained responses to pure and paired tones. These data leave open the question as to which of several alternative strategies underlie flight tone matching behavior in mosquitoes. PMID:20348350

  7. Repellent properties of Cardiospermum halicacabum Linn. (Family: Sapindaceae) plant leaf extracts against three important vector mosquitoes

    PubMed Central

    Govindarajan, M; Sivakumar, R

    2012-01-01

    Objective To determine repellent activity of hexane, ethyl acetate, benzene, chloroform and methanol extract of Cardiospermum halicacabum (C. halicacabum) against Culex quinquefasciatus (Cx. quinquefasciatus), Aedes aegypti (Ae. aegypti) and Anopheles stephensi (An. stephensi). Methods Evaluation was carried out in a net cage (45 cm×30 cm×25 cm) containing 100 blood starved female mosquitoes of three mosquito species and were assayed in the laboratory condition by using the protocol of WHO 2005; The plant leaf crude extracts of C. halicacabum was applied at 1.0, 2.5, and 5.0 mg/cm2 separately in the exposed area of the fore arm. Only ethanol served as control. Results In this observation, the plant crude extracts gave protection against mosquito bites without any allergic reaction to the test person, and also, the repellent activity was dependent on the strength of the plant extracts. The tested plant crude extracts had exerted promising repellent against all the three mosquitoes. Conclusions From the results it can be concluded the crude extract of C. halicacabum was potential for controlling Cx. quinquefasciatus, Ae. aegypti and An. stephensi mosquitoes. PMID:23569979

  8. Synthesis and characterization of silver nanoparticles using Gmelina asiatica leaf extract against filariasis, dengue, and malaria vector mosquitoes.

    PubMed

    Muthukumaran, Udaiyan; Govindarajan, Marimuthu; Rajeswary, Mohan; Hoti, S L

    2015-05-01

    Mosquitoes are blood-feeding insects and serve as the most important vectors for spreading human diseases such as malaria, yellow fever, dengue fever, and filariasis. The continued use of synthetic insecticides has resulted in resistance in mosquitoes. Synthetic insecticides are toxic and affect the environment by contaminating soil, water, and air, and then natural products may be an alternative to synthetic insecticides because they are effective, biodegradable, eco-friendly, and safe to environment. Botanical origin may serve as suitable alternative biocontrol techniques in the future. The present study was carried out to establish the larvicidal potential of leaf extracts of Gmelina asiatica and synthesized silver nanoparticles using aqueous leaf extract against late third instar larvae of Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. Larvae were exposed to varying concentrations of plant extracts and synthesized AgNPs for 24 h. The results were recorded from UV-visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy analysis support the biosynthesis and characterization of AgNPs. The maximum efficacy was observed in synthesized AgNPs against the larvae of An. stephensi (lethal dose (LC₅₀) = 22.44 μg/mL; LC₉₀ 40.65 μg/mL), Ae. aegypti (LC₅₀ = 25.77 μg/mL; LC₉₀ 45.98 μg/mL), and C. quinquefasciatus (LC₅₀ = 27.83 μg/mL; LC₉₀ 48.92 μg/mL), respectively. No mortality was observed in the control. This is the first report on mosquito larvicidal activity of plant-synthesized nanoparticles. Thus, the use of G. asiatica to synthesize silver nanoparticles is a rapid, eco-friendly, and a single-step approach and the AgNps formed can be potential mosquito larvicidal agents. PMID:25666372

  9. 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.

    PubMed

    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. PMID:26995063

  10. One-pot fabrication of silver nanocrystals using Nicandra physalodes: A novel route for mosquito vector control with moderate toxicity on non-target water bugs.

    PubMed

    Govindarajan, Marimuthu; Khater, Hanem F; Panneerselvam, Chellasamy; Benelli, Giovanni

    2016-08-01

    Mosquitoes (Diptera: Culicidae) as vectors for important diseases and parasites causing millions of deaths every year. The use of synthetic pesticides against Culicidae leads to resistance and environmental concerns. Therefore, eco-friendly control tools are a priority. In this research, Nicandra physalodes-mediated synthesis of silver nanoparticles (Ag NPs) was conducted, in order to control larval populations of three important mosquito vectors, Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. Biofabricated Ag NPs were characterized using UV-vis spectrophotometry, XRD, FTIR spectroscopy, SEM, and TEM analyses. Ag NPs were highly toxic against the three mosquito vectors. Maximum efficacy was detected against A. stephensi (LC50=12.39μg/mL), followed by Ae. aegypti (LC50=13.61μg/mL) and Cx. quinquefasciatus (LC50=14.79μg/mL). Interestingly, Ag NPs were safer for the non-target aquatic organism Diplonychus indicus sharing the same aquatic habitats of mosquito larvae. LC50 and LC90 values were 1032.81 and 19,076.59μg/mL, respectively. Overall, our results highlight that N. physalodes-fabricated Ag NPs are a promising for development of eco-friendly larvicides against mosquito vectors, with negligible toxicity against non-target aquatic water bugs. PMID:27473981

  11. Impact of Climate and Mosquito Vector Abundance on Sylvatic Arbovirus Circulation Dynamics in Senegal

    PubMed Central

    Althouse, Benjamin M.; Hanley, Kathryn A.; Diallo, Mawlouth; Sall, Amadou A.; Ba, Yamar; Faye, Ousmane; Diallo, Diawo; Watts, Douglas M.; Weaver, Scott C.; Cummings, Derek A. T.

    2015-01-01

    Sylvatic arboviruses have been isolated in Senegal over the last 50 years. The ecological drivers of the pattern and frequency of virus infection in these species are largely unknown. We used time series analysis and Bayesian hierarchical count modeling on a long-term arbovirus dataset to test associations between mosquito abundance, weather variables, and the frequency of isolation of dengue, yellow fever, chikungunya, and Zika viruses. We found little correlation between mosquito abundance and viral isolations. Rainfall was a negative predictor of dengue virus (DENV) isolation but a positive predictor of Zika virus isolation. Temperature was a positive predictor of yellow fever virus (YFV) isolations but a negative predictor of DENV isolations. We found slight interference between viruses, with DENV negatively associated with concurrent YFV isolation and YFV negatively associated with concurrent isolation of chikungunya virus. These findings begin to characterize some of the ecological associations of sylvatic arboviruses with each other and climate and mosquito abundance. PMID:25404071

  12. The ecology of vector snail habitats and mosquito breeding-places

    PubMed Central

    Muirhead-Thomson, R. C.

    1958-01-01

    The ecology of freshwater snails—in particular those which act as intermediate hosts of bilharziasis—is reviewed in the light of the much more extensive knowledge available on the breeding-places of anopheline mosquitos. Experimental ecological methods are recommended for the field and laboratory investigation of a number of common problems involved in the study of snail habitats and mosquito breeding-places. Among the environmental factors discussed are temperature, oxygen concentration, water movement, pollution and salinity. Sampling methods for estimating populations of both snails and mosquito larvae are also described. An attempt is made to show how malacologists and entomologists alike would benefit from improved facilities for keeping abreast of general developments in the wider field of freshwater ecology. PMID:13596888

  13. Impact of climate and mosquito vector abundance on sylvatic arbovirus circulation dynamics in Senegal.

    PubMed

    Althouse, Benjamin M; Hanley, Kathryn A; Diallo, Mawlouth; Sall, Amadou A; Ba, Yamar; Faye, Ousmane; Diallo, Diawo; Watts, Douglas M; Weaver, Scott C; Cummings, Derek A T

    2015-01-01

    Sylvatic arboviruses have been isolated in Senegal over the last 50 years. The ecological drivers of the pattern and frequency of virus infection in these species are largely unknown. We used time series analysis and Bayesian hierarchical count modeling on a long-term arbovirus dataset to test associations between mosquito abundance, weather variables, and the frequency of isolation of dengue, yellow fever, chikungunya, and Zika viruses. We found little correlation between mosquito abundance and viral isolations. Rainfall was a negative predictor of dengue virus (DENV) isolation but a positive predictor of Zika virus isolation. Temperature was a positive predictor of yellow fever virus (YFV) isolations but a negative predictor of DENV isolations. We found slight interference between viruses, with DENV negatively associated with concurrent YFV isolation and YFV negatively associated with concurrent isolation of chikungunya virus. These findings begin to characterize some of the ecological associations of sylvatic arboviruses with each other and climate and mosquito abundance. PMID:25404071

  14. Plants traditionally used as mosquito repellents and the implication for their use in vector control.

    PubMed

    Tisgratog, Rungarun; Sanguanpong, Unchalee; Grieco, John P; Ngoen-Kluan, Ratchadawan; Chareonviriyaphap, Theeraphap

    2016-05-01

    Numerous plants with insect repelling properties are native to the tropics where they are produced for a wide range of medicinal purposes. In Thailand, these native plant species have a history of use for personal protection against biting insects. From our investigation we identified 37 plant species within 14 plant families that showed some mosquito repellent properties. Of these, 9 plant species were characterized using an excito-repellency test system against several Thai mosquito species. Results from these studies revealed that five essential oils extracted from plants demonstrated promising insect repellent activity. These active ingredients show promise for further development into formulations that may serve as alternatives to DEET or possibly be used as natural bio-pesticides to kill mosquitoes. PMID:26826392

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

    PubMed

    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

  16. Olfactory learning and memory in the disease vector mosquito Aedes aegypti

    PubMed Central

    Vinauger, Clément; Lutz, Eleanor K.; Riffell, Jeffrey A.

    2014-01-01

    Olfactory learning in blood-feeding insects, such as mosquitoes, could play an important role in host preference and disease transmission. However, standardised protocols allowing testing of their learning abilities are currently lacking, and how different olfactory stimuli are learned by these insects remains unknown. Using a Pavlovian conditioning paradigm, we trained individuals and groups of Aedes aegypti mosquitoes to associate an odorant conditioned stimulus (CS) with a blood-reinforced thermal stimulus (unconditioned stimulus; US). Results showed, first, that mosquitoes could learn the association between L-lactic acid and the US, and retained the association for at least 24 h. Second, the success of olfactory conditioning was dependent upon the CS – some odorants that elicited indifferent responses in naïve mosquitoes, such as L-lactic acid and 1-octen-3-ol, were readily learned, whereas others went from aversive to attractive after training (Z-3-hexen-1-ol) or were untrainable (β-myrcene and benzyl alcohol). Third, we examined whether mosquitoes' ability to learn could interfere with the action of the insect repellent DEET. Results demonstrated that pre-exposure and the presence of DEET in the CS reduced the aversive effects of DEET. Last, the nature of the formed memories was explored. Experiments using cold-shock treatments within the first 6 h post-training (for testing anaesthesia-resistant memory) and a protein synthesis inhibitor (cycloheximide; to disrupt the formation of long-term memory) both affected mosquitoes' performances. Together, these results show that learning is a crucial component in odour responses in A. aegypti, and provide the first evidence for the functional role of different memory traces in these responses. PMID:24737761

  17. Dengue virus infection alters post-transcriptional modification of microRNAs in the mosquito vector Aedes aegypti.

    PubMed

    Etebari, Kayvan; Osei-Amo, Solomon; Blomberg, Simon Phillip; Asgari, Sassan

    2015-01-01

    Recent discoveries regarding the importance of isomiRs have increased our understanding of the regulatory complexities of the miRNAome. Observed changes in the miRNA profiles in mosquitoes infected with flaviviruses have implicated small RNAs in the interactions between viruses and their vectors. Here we analysed the isomiR profiles of both uninfected and infected Aedes aegypti mosquitoes with the major human pathogen dengue virus (DENV). We found that several specific isomiRs were significantly altered in their abundance patterns in response to DENV infection potentially affecting their target repertoire. Notable among these were isomiR variants which displayed arm-switching. We also demonstrate that modifications to the 3p end of miRNAs are vastly more prevalent than those at the 5p ends. We also observed that in only 45% of Ae. aegypti miRNAs the most abundant read matches the exact sequence reported in miRBase. Further, we found positive correlations between the number of mature miRNA reads, pre-miRNA length, GC content and secondary structure minimum free energy with the number of isomiRs. The findings presented here provide some evidence that isomiR production is not a random phenomenon and may be important in DENV replication in its vector. PMID:26514826

  18. Effects of rainfall and salinity increase on prevalence of vector mosquitoes in coastal areas of Alappuzha district, Kerala.

    PubMed

    Balasubramanian, R; Nikhil, T L

    2015-11-01

    Seasonal abundance patterns for Japanese encephalitis vectors along climatic variations were studied in the coastal areas of Alappuzha district from June 2012 to May 2013. A total of 10563 female mosquitoes belonging to eleven species were collected. Culex gelidusTheobald (50.04%), Cx. tritaeniorhynchus Giles (26.50%), and Cx. sitiens Wiedemann (7.55%) were found to be most common in these areas. Cx. sitiens females were collected from each sampling occasion from early monsoon season June to late summer May with a distinct peak in April at 7.18 electrical conductivity (EC). Cx. sitiens abundance increased rapidly when monthly salinity level consistently exceeded 7.76, occurring in March at 7.76 and April at 7.18 electrical conductivity (EC). While analyzing correlation of Cx. sitiens density with salinity and rainfall was significant. High density of Cx. gelidus was greatly influenced by total rainfall and it was found to be significantly correlated with Per Man Hour (PMH) (P < 0.05), whereas salinity was inversely correlated with mosquito density (P < 0.001). The abundance of Cx. tritaeniorhynchus was lowest in June (rainy season) and increased in October, with densities increasing sharply during summer season in April (83 PMH). During summer, due to increased salinity Cx. sitiens density increased. These areas may develop in to brackish and saline water populated by Cx. sitiens, which can be new vectors for Japanese encephalitis or West Nile virus in these areas. PMID:26688968

  19. Vector Competence of Selected African Mosquito (Diptera: Culicidae) Species for Rift Valley Fever Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Outbreaks of Rift Valley fever (RVF) in Egypt, Yemen, and Saudi Arabia have indicated the potential for this disease to spread from its enzootic areas in sub-Saharan Africa. Because little is known about the potential for most African mosquito species to transmit RVF virus (RVFV), we conducted stud...

  20. Effect of environmental temperature on the vector competence of mosquitoes for Rift Valley fever virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Environmental temperature has been shown to affect the ability of mosquitoes to transmit numerous arboviruses and for Rift Valley fever virus (RVFV) in particular. We evaluated the effect of incubation temperatures ranging from 14-26ºC on infection, dissemination, and transmission rates for Culex ta...

  1. Examination of the genetic basis for sexual dimorphism in the Aedes aegypti (dengue vector mosquito) pupal brain

    PubMed Central

    2014-01-01

    Background Most animal species exhibit sexually dimorphic behaviors, many of which are linked to reproduction. A number of these behaviors, including blood feeding in female mosquitoes, contribute to the global spread of vector-borne illnesses. However, knowledge concerning the genetic basis of sexually dimorphic traits is limited in any organism, including mosquitoes, especially with respect to differences in the developing nervous system. Methods Custom microarrays were used to examine global differences in female vs. male gene expression in the developing pupal head of the dengue vector mosquito, Aedes aegypti. The spatial expression patterns of a subset of differentially expressed transcripts were examined in the developing female vs. male pupal brain through in situ hybridization experiments. Small interfering RNA (siRNA)-mediated knockdown studies were used to assess the putative role of Doublesex, a terminal component of the sex determination pathway, in the regulation of sex-specific gene expression observed in the developing pupal brain. Results Transcripts (2,527), many of which were linked to proteolysis, the proteasome, metabolism, catabolic, and biosynthetic processes, ion transport, cell growth, and proliferation, were found to be differentially expressed in A. aegypti female vs. male pupal heads. Analysis of the spatial expression patterns for a subset of dimorphically expressed genes in the pupal brain validated the data set and also facilitated the identification of brain regions with dimorphic gene expression. In many cases, dimorphic gene expression localized to the optic lobe. Sex-specific differences in gene expression were also detected in the antennal lobe and mushroom body. siRNA-mediated gene targeting experiments demonstrated that Doublesex, a transcription factor with consensus binding sites located adjacent to many dimorphically expressed transcripts that function in neural development, is required for regulation of sex-specific gene

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

    PubMed Central

    Limwagu, Alex Julius; Siria, Doreen Josen; Kaindoa, Emmanuel Wilson; Okumu, Fredros Oketch

    2016-01-01

    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 be further

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

    PubMed

    Mwangungulu, Stephen Peter; Sumaye, Robert David; Limwagu, Alex Julius; Siria, Doreen Josen; Kaindoa, Emmanuel Wilson; Okumu, Fredros Oketch

    2016-01-01

    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 be further

  4. Molecular detection of Wolbachia pipientis in natural populations of mosquito vectors of Dirofilaria immitis from continental Portugal: first detection in Culex theileri.

    PubMed

    DE Pinho Mixão, V; Mendes, A M; Maurício, I L; Calado, M M; Novo, M T; Belo, S; Almeida, A P G

    2016-09-01

    Wolbachia pipientis (Rickettsiales: Rickettsiaceae) protects mosquitoes from infections with arboviruses and parasites. However, the effect of its co-infection on vector competence for Dirofilaria immitis (Spirurida: Onchocercidae) in the wild has not been investigated. This study aimed to screen vectors of D. immitis for wPip, to characterize these, and to investigate a possible association between the occurrence of W. pipientis and that of the nematode. The presence of W. pipientis was assessed in the five mosquito potential vectors of D. immitis in Portugal. Polymerase chain reaction (PCR) products were sequenced, and wPip haplotypes were determined by PCR-restricted fragment length polymorphism (RFLP). Results showed that wPip was detected in 61.5% of Culex pipiens (Diptera: Culicidae) pools and 6.3% of Culex theileri pools. wPip 16s rRNA sequences found in Cx. theileri exactly match those from Cx. pipiens, confirming a mosquito origin, rather than a nematode origin, as some specimens were infected with D. immitis. Only wPip haplotype I was found. No association was found between the presence of wPip and D. immitis in mosquitoes and hence a role for this endosymbiont in influencing vectorial competence is yet to be identified. This study contributes to understanding of wPip distribution in mosquito populations and, to the best of the authors' knowledge, is the first report of natural infections by wPip in Cx. theileri. PMID:27279553

  5. Toxicity of essential oil from Indian borage on the larvae of the African malaria vector mosquito, Anopheles gambiae

    PubMed Central

    2012-01-01

    Background Essential oils are currently studied for the control of different disease vectors, because of their efficacy on targeted organisms. In the present investigation, the larvicidal potential of essential oil extracted from Indian borage (Plectranthus amboinicus) was studied against the African anthropophagic malaria vector mosquito, Anopheles gambiae. The larvae of An. gambiae s.s laboratory colony and An. gambiae s.l of wild populations were assayed and the larval mortality was observed at 12, 24 and 48 h after exposure period with the concentrations of 3.125, 6.25, 12.5, 25, 50 and 100 ppm. Findings Larval mortality rates of the essential oil was entirely time and dose dependent. The LC50 values of the laboratory colony were 98.56 (after 12h) 55.20 (after 24 h) and 32.41 ppm (after 48 h) and the LC90 values were 147.40 (after 12h), 99.09 (after 24 h) and 98.84 ppm (after 48 h). The LC50 and LC90 values of the wild population were 119.52, 179.85 (after 12h) 67.53, 107.60 (after 24 h) and 25.51, 111.17 ppm (after 48 h) respectively. The oil showed good larvicidal potential after 48 h of exposure period against An. gambiae. The essential oil of Indian borage is a renowned natural source of larvicides for the control of the African malaria vector mosquito, An. gambiae. Conclusion The larvicidal efficacy shown by plant extracts against An. gambiae should be tested in semi field and small scale trials for effective compounds to supplement the existing larval control tools. PMID:23206364

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

    PubMed Central

    Omondi, David; Masiga, Daniel K.; Ajamma, Yvonne Ukamaka; Fielding, Burtram C.; Njoroge, Laban; Villinger, Jandouwe

    2015-01-01

    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. PMID:26230507

  7. Use of a simple DNA extraction method for high-throughput detection of filarial parasite Wuchereria bancrofti in the vector mosquitoes.

    PubMed

    Vasuki, V; Subramanian, S; Hoti, S L; Jambulingam, P

    2012-12-01

    Molecular xenomonitoring of filariasis is the detection of filarial DNA in mosquitoes by PCR and a useful tool for monitoring transmission. DNA extraction coupled with PCR allows rapid detection of the presence or absence of the filarial parasite in vector mosquitoes compared to traditional method of manual dissection of the mosquito and observation for parasite under a microscope. A Tris-EDTA (TE) buffer-based boiling method of DNA extraction developed earlier by us was employed and explored for its suitability in the detection of Wuchereria bancrofti DNA in pools of Culex quinquefasciatus mosquitoes in real-time PCR assay. In this preliminary study, 1,000 laboratory-reared C. quinquefasciatus were made into 40 pools, each containing 25 mosquitoes spiked with 2mf. DNA from the first 20 pools was extracted using Qiagen DNeasy blood and tissue kit as standard, and the other 20 pools were subjected to TE buffer-based boiling method of DNA extraction. When the results (Ct values) obtained for DNA samples extracted by TE buffer-based boiling method were compared with that of the DNA samples extracted by the standard Qiagen method, they were found to be highly concordant without any significant difference (P = 0.9). Besides being cost- and time-effective, this protocol was found useful in extracting filarial DNA from two other mosquito genus Aedes and Anopheles, species of which have been reported as important vectors of W. bancrofti in other endemic regions of the world. Thus, TE buffer-based boiling method of DNA extraction is useful for the high-throughput detection of W. bancrofti in vector mosquitoes. PMID:22777703

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

    PubMed Central

    2015-01-01

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

  9. Investigating the Potential Range Expansion of the Vector Mosquito Aedes Aegypti in Mexico with NASA Earth Science Remote Sensing Results

    NASA Technical Reports Server (NTRS)

    Crosson, W. L.; Estes, M. G.; Estes, S. M.; Hayden, M.; Monaghan, A. J.; Eisen, L.; Lozano-Fuentes, S.; Ochoa, C.; Tapia, B.; Welsh-Rodriquez, C. M.; Quattrochi, D.; MorenoMadrinan, M. J.

    2012-01-01

    In tropical and sub ]tropical regions, the mosquito Aedes aegypti is the major vector for the virus causing dengue, a serious public health issue in these areas. Through ongoing NSF- and NASA-funded studies, field surveys of Aedes aegypti and an integrated modeling approach are being used to improve our understanding of the potential range of the mosquito to expand toward heavily populated high elevation areas such as Mexico City under various climate change and socio ]economic scenarios. This work serves three primary objectives: (1) Employ NASA remotely-sensed data to supplement the environmental monitoring and modeling component of the project. These data-- for example, surface temperature, precipitation, vegetation indices, soil moisture and elevation-- are critical for understanding the habitat necessary for mosquito survival and abundance; (2) Implement training sessions to instruct scientists and students from Mexico and the U.S. on how to use remote sensing and implement the NASA SERVIR Regional Visualization and Monitoring System; (3) Employ the SERVIR framework to optimize the dissemination of key project results in order to increase their societal relevance and benefits in developing climate adaptation strategies. Field surveys of larval, pupal and adult Aedes aegypti, as well as detailed physical and social household characteristics, were conducted in the summers of 2011and 2012 at geographic scales from the household to the community along a transect from sea level to 2400 m ASL. These data are being used in models to estimate Aedes aegypti habitat suitability. In 2011, Aedes aegypti were identified at an elevation of over 2150 m in Puebla, the highest elevation at which this species has been observed.

  10. Investigating the Potential Range Expansion of the Vector Mosquito Aedes aegypti in Mexico with NASA Earth Science Remote Sensing Results

    NASA Astrophysics Data System (ADS)

    Crosson, W. L.; Eisen, L.; Estes, M. G.; Estes, S. M.; Hayden, M.; Lozano-Fuentes, S.; Monaghan, A. J.; Moreno Madriñán, M. J.; Ochoa, C.; Quattrochi, D.; Tapia, B.; Welsh-Rodriguez, C. M.

    2012-12-01

    In tropical and sub-tropical regions, the mosquito Aedes aegypti is the major vector for the virus causing dengue, a serious public health issue in these areas. Through ongoing NSF- and NASA-funded studies, field surveys of Aedes aegypti and an integrated modeling approach are being used to improve our understanding of the potential range of the mosquito to expand toward heavily populated high elevation areas such as Mexico City under various climate change and socio-economic scenarios. This work serves three primary objectives: (1) Employ NASA remotely-sensed data to supplement the environmental monitoring and modeling component of the project. These data -- for example, surface temperature, precipitation, vegetation indices, soil moisture and elevation -- are critical for understanding the habitat necessary for mosquito survival and abundance; (2) Implement training sessions to instruct scientists and students from Mexico and the U.S. on how to use remote sensing and implement the NASA SERVIR Regional Visualization and Monitoring System; (3) Employ the SERVIR framework to optimize the dissemination of key project results in order to increase their societal relevance and benefits in developing climate adaptation strategies. Field surveys of larval, pupal and adult Aedes aegypti, as well as detailed physical and social household characteristics, were conducted in the summers of 2011and 2012 at geographic scales from the household to the community along a transect from sea level to 2400 m ASL. These data are being used in models to estimate Aedes aegypti habitat suitability. In 2011, Aedes aegypti were identified at an elevation of over 2150 m in Puebla, the highest elevation at which this species has been observed.

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

    PubMed

    Price, Dana C; Fonseca, Dina M

    2015-01-01

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

  12. Models to assess how best to replace dengue virus vectors with Wolbachia-infected mosquito populations.

    PubMed

    Zhang, Xianghong; Tang, Sanyi; Cheke, Robert A

    2015-11-01

    Dengue fever is increasing in importance in the tropics and subtropics. Endosymbiotic Wolbachia bacteria as novel control methods can reduce the ability of virus transmission. So, many mosquitoes infected with Wolbachia are released in some countries so that strategies for population replacement can be fulfilled. However, not all of these field trails are successful, for example, releases on Tri Nguyen Island, Vietnam in 2013 failed. Thus, we evaluated a series of relevant issues such as (a) why do some releases fail? (b) What affects the success of population replacement? And (c) Whether or not augmentation can block the dengue diseases in field trials. If not, how we can success be achieved? Models with and without augmentation, incorporating the effects of cytoplasmic incompatibility (CI) and fitness effects are proposed to describe the spread of Wolbachia in mosquito populations. Stability analysis revealed that backward bifurcations and multiple attractors may exist, which indicate that initial quantities of infected and uninfected mosquitoes, augmentation methods (timing, quantity, order and frequency) may affect the success of the strategies. The results show that successful population replacement will rely on selection of suitable strains of Wolbachia and careful design of augmentation methods. PMID:26407645

  13. Pest Management Practices for the Military: Novel Field Studies to Develop Methods to Protect Deployed Troops from Mosquito, Filth/Biting Flies, and Sand Fly Vectors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    New techniques that we developed 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 illustrated included (1) novel military personal protection methods, (2) barrier treatments...

  14. PREPARING FOR RIFT VALLEY FEVER IN THE U.S.: IMPLEMENTING GIS AND REMOTE SENSING TO UNDERSTAND POPULATION DYNAMICS OF MOSQUITO VECTORS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Much work has been done to understand the pathways along which Rift Valley fever (RVF) could be introduced to the U.S., to study the vector competence and vectorial capacity of various mosquito species that could transmit RVF, and to develop safe vaccines and reliable test kits. However, we do not ...

  15. Assessing density dependence in the transmission of lymphatic filariasis: uptake and development of Wuchereria bancrofti microfilariae in the vector mosquitoes.

    PubMed

    Stolk, W A; Van Oortmarssen, G J; Subramanian, S; Das, P K; Borsboom, G J J M; Habbema, J D F; de Vlas, S J

    2004-03-01

    Understanding density dependence in the transmission of lymphatic filariasis is essential for assessing the prospects of elimination. This study seeks to quantify the relationship between microfilaria (Mf) density in human blood and the number of third stage (L3) larvae developing in the mosquito vectors Aedes polynesiensis Marks and Culex quinquefasciatus Say (Diptera: Culicidae) after blood-feeding. Two types of curves are fitted to previously published data. Fitting a linearized power curve through the data allows for correction for measurement error in human Mf counts. Ignoring measurement error leads to overestimation of the strength of density dependence; the degree of overestimation depends on the accuracy of measurement of Mf density. For use in mathematical models of transmission of lymphatic filariasis, a hyperbolic saturating function is preferable. This curve explicitly estimates the Mf uptake and development at lowest Mf densities and the average maximum number of L3 that can develop in mosquitoes. This maximum was estimated at 23 and 4 for Ae. polynesiensis and Cx. quinquefasciatus, respectively. PMID:15009446

  16. Malathion resistance and prevalence of the malathion carboxylesterase mechanism in populations of mosquito vectors of disease in Sri Lanka.

    PubMed Central

    Karunaratne, S. H.; Hemingway, J.

    2001-01-01

    OBJECTIVE: To determine the levels of malathion resistance and prevalence of the malathion carboxylesterase mechanism among mosquitoes in Sri Lanka. METHODS: Bioassays were carried out using WHO-recommended methods on samples of the following Sri Lankan mosquito vectors: Culex quinquefasciatus, C. tritaeniorhynchus, C gelidus, Anopheles culicifacies B, A. subpictus, Aedes aegypti and A. albopictus. FINDINGS Malathion-specific carboxylesterase mechanisms were found in A. culicifaies and A. subpictus, both giving high rates of insecticide metabolism. In contrast, malathion resistance in C. quinquefasciatus and C. tritaeniorhynchus is linked to broad-spectrum resistance to organophosphorus compounds due to elevated levels of esterases that sequester malaoxon, but are unable to metabolize malathion. CONCLUSIONS: Resistance among the Anophelesspp. must have occurred as a direct result of antimalarial activities, since malathion use in Sri Lanka is limited to public health treatments. In contrast, resistance among Culex spp. has resulted from large-scale use of the organophosphorus insecticide group as larvicides for filariasis control and on rice paddy, where C tritaeniorhynchus predominantly breeds, for agricultural purposes. PMID:11731814

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

    PubMed

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

    2014-12-01

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

  18. Fine-scale population genetic structure of a wildlife disease vector: The southern house mosquito on the island of Hawaii

    USGS Publications Warehouse

    Keyghobadi, N.; LaPointe, D.; Fleischer, R.C.; Fonseca, D.M.

    2006-01-01

    The southern house mosquito, Culex quinquefasciatus, is a widespread tropical and subtropical disease vector. In the Hawaiian Islands, where it was introduced accidentally almost two centuries ago, it is considered the primary vector of avian malaria and pox. Avian malaria in particular has contributed to the extinction and endangerment of Hawaii's native avifauna, and has altered the altitudinal distribution of native bird populations. We examined the population genetic structure of Cx. quinquefasciatus on the island of Hawaii at a smaller spatial scale than has previously been attempted, with particular emphasis on the effects of elevation on population genetic structure. We found significant genetic differentiation among populations and patterns of isolation by distance within the island. Elevation per se did not have a limiting effect on gene flow; however, there was significantly lower genetic diversity among populations at mid elevations compared to those at low elevations. A recent sample taken from just above the predicted upper altitudinal distribution of Cx. quinquefasciatus on the island of Hawaii was confirmed as being a temporary summer population and appeared to consist of individuals from more than one source population. Our results indicate effects of elevation gradients on genetic structure that are consistent with known effects of elevation on population dynamics of this disease vector. ?? 2006 The Authors.

  19. Influence of short time exposure to an insect growth regulator, hexaflumuron, on mortality and adult emergence of vector mosquitoes.

    PubMed

    Vasuki, V; Rajavel, A R

    1992-01-01

    Hexaflumuron, an insect growth regulator (IGR), was found to greatly affect the development of immatures and emergence of adults of three species of vector mosquitoes, Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi, when larvae were subjected to short time exposure of < or = 1 h. This IGR could completely prevent adult emergence even at a minimum exposure time of 10 min at 0.001, 0.01 and 0.1 mg/l. On treatment, larval and pupal mortality as well as varying degrees of morphogenetic abnormalities were induced in immatures and adults of the three species. Four weeks of control achieved in a slow moving sullage canal breeding Culex quinquefasciatus indicates that this IGR can be of use in such breeding habitats. PMID:1308571

  20. Highly efficient Cas9-mediated gene drive for population modification of the malaria vector mosquito Anopheles stephensi

    PubMed Central

    Gantz, Valentino M.; Tatarenkova, Olga; Fazekas, Aniko; Macias, Vanessa M.; Bier, Ethan; James, Anthony A.

    2015-01-01

    Genetic engineering technologies can be used both to create transgenic mosquitoes carrying antipathogen effector genes targeting human malaria parasites and to generate gene-drive systems capable of introgressing the genes throughout wild vector populations. We developed a highly effective autonomous Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-associated protein 9 (Cas9)-mediated gene-drive system in the Asian malaria vector Anopheles stephensi, adapted from the mutagenic chain reaction (MCR). This specific system results in progeny of males and females derived from transgenic males exhibiting a high frequency of germ-line gene conversion consistent with homology-directed repair (HDR). This system copies an ∼17-kb construct from its site of insertion to its homologous chromosome in a faithful, site-specific manner. Dual anti-Plasmodium falciparum effector genes, a marker gene, and the autonomous gene-drive components are introgressed into ∼99.5% of the progeny following outcrosses of transgenic lines to wild-type mosquitoes. The effector genes remain transcriptionally inducible upon blood feeding. In contrast to the efficient conversion in individuals expressing Cas9 only in the germ line, males and females derived from transgenic females, which are expected to have drive component molecules in the egg, produce progeny with a high frequency of mutations in the targeted genome sequence, resulting in near-Mendelian inheritance ratios of the transgene. Such mutant alleles result presumably from nonhomologous end-joining (NHEJ) events before the segregation of somatic and germ-line lineages early in development. These data support the design of this system to be active strictly within the germ line. Strains based on this technology could sustain control and elimination as part of the malaria eradication agenda. PMID:26598698

  1. Highly efficient Cas9-mediated gene drive for population modification of the malaria vector mosquito Anopheles stephensi.

    PubMed

    Gantz, Valentino M; Jasinskiene, Nijole; Tatarenkova, Olga; Fazekas, Aniko; Macias, Vanessa M; Bier, Ethan; James, Anthony A

    2015-12-01

    Genetic engineering technologies can be used both to create transgenic mosquitoes carrying antipathogen effector genes targeting human malaria parasites and to generate gene-drive systems capable of introgressing the genes throughout wild vector populations. We developed a highly effective autonomous Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-associated protein 9 (Cas9)-mediated gene-drive system in the Asian malaria vector Anopheles stephensi, adapted from the mutagenic chain reaction (MCR). This specific system results in progeny of males and females derived from transgenic males exhibiting a high frequency of germ-line gene conversion consistent with homology-directed repair (HDR). This system copies an ∼ 17-kb construct from its site of insertion to its homologous chromosome in a faithful, site-specific manner. Dual anti-Plasmodium falciparum effector genes, a marker gene, and the autonomous gene-drive components are introgressed into ∼ 99.5% of the progeny following outcrosses of transgenic lines to wild-type mosquitoes. The effector genes remain transcriptionally inducible upon blood feeding. In contrast to the efficient conversion in individuals expressing Cas9 only in the germ line, males and females derived from transgenic females, which are expected to have drive component molecules in the egg, produce progeny with a high frequency of mutations in the targeted genome sequence, resulting in near-Mendelian inheritance ratios of the transgene. Such mutant alleles result presumably from nonhomologous end-joining (NHEJ) events before the segregation of somatic and germ-line lineages early in development. These data support the design of this system to be active strictly within the germ line. Strains based on this technology could sustain control and elimination as part of the malaria eradication agenda. PMID:26598698

  2. Chemical composition and larvicidal activity of Blumea densiflora essential oils against Anopheles anthropophagus: a malarial vector mosquito.

    PubMed

    Zhu, Liang; Tian, Yingjuan

    2011-11-01

    Blumea densiflora, an edible and medicinal plant, is chiefly distributed in Southeast Asia and South Asia. Essential oils extracted by steam distillation from B. densiflora were investigated for their chemical composition and larvicidal activity against Anopheles anthropophagus, the primary vector of malaria in China and other East Asian countries. Totally, 46 compounds were identified by gas chromatography and mass spectroscopy. The major chemical compounds identified were borneol (11.43%), germacrene D (8.66%), β-caryophyllene (6.68%), γ-terpinene (4.35%), sabinene (4.34%), and β-bisabolene (4.24%). A series of concentrations of essential oil (that ranged from 6.25 to 150 ppm) were tested against A. anthropophagus fourth-instar larvae according to WHO recommendation. In general, larval mortality increased as concentration and exposure time increased, indicating a dose-dependent effect, and high insecticidal activity showed that 100% mortality occurred within 6 h at 150 ppm, 10 h at 100 ppm, 30 h at 50 ppm, and 30 h at 25 ppm essential oil concentration. The LC(50) values were 22.32 (after 12 h) and 10.55 ppm (after 24 h), and the LC(90) values were 54.04 (after 12 h) and 33.56 ppm (after 24 h). Pylarvex, the reference standard, had better larvicidal activity, causing 100% mortality within 2 h at 150 ppm and within 6 h at 6.25 ppm. The results clearly reveal that the essential oil of B. densiflora served as a potential, eco-friendly mosquito larvicide against the malarial vector mosquito A. anthropophagus. PMID:21556689

  3. Mosquito larvicidal activity of Aloe vera (Family: Liliaceae) leaf extract and Bacillus sphaericus, against Chikungunya vector, Aedes aegypti

    PubMed Central

    Subramaniam, Jayapal; Kovendan, Kalimuthu; Mahesh Kumar, Palanisamy; Murugan, Kadarkarai; Walton, William

    2012-01-01

    The bio-efficacy of Aloe vera leaf extract and bacterial insecticide, Bacillus sphaericus larvicidal activity was assessed against the first to fourth instars larvae of Aedes aegypti, under the laboratory conditions. The plant material was shade dried at room temperature and powdered coarsely. A. vera and B. sphaericus show varied degrees of larvicidal activity against various instars larvae of A. aegypti. The LC50 of A. vera against the first to fourth instars larvae were 162.74, 201.43, 253.30 and 300.05 ppm and the LC90 442.98, 518.86, 563.18 and 612.96 ppm, respectively. B. sphaericus against the first to fourth instars larvae the LC50 values were 68.21, 79.13, 93.48, and 107.05 ppm and the LC90 values 149.15, 164.67, 183.84, and 201.09 ppm, respectively. However, the combined treatment of A. vera + B. sphaericus (1:2) material shows highest larvicidal activity of the LC50 values 54.80, 63.11, 74.66 and 95.10 ppm; The LC90 values of 145.29, 160.14, 179.74 and 209.98 ppm, against A. aegypti in all the tested concentrations than the individuals and clearly established that there is a substantial amount of synergist act. The present investigation clearly exhibits that both A. vera and B. sphaericus materials could serve as a potential larvicidal agent. Since, A. aegypti is a container breeder vector mosquito this user and eco-friendly and low-cost vector control strategy could be a viable solution to the existing dengue disease burden. Therefore, this study provides first report on the mosquito larvicidal activity the combined effect of A. vera leaf extract and B. sphaericus against as target species of A. aegypti. PMID:23961212

  4. A comparison of two commercial mosquito traps for the capture of malaria vectors in northern belize, central america.

    PubMed

    Wagman, Joseph; Grieco, John P; Bautista, Kim; Polanco, Jorge; Briceño, Ireneo; King, Russell; Achee, Nicole L

    2014-09-01

    To achieve maximum success from any vector control intervention, it is critical to identify the most efficacious tools available. The principal aim of this study was to evaluate the efficacy of 2 commercially available adult mosquito traps for capturing Anopheles albimanus and An. vestitipennis, 2 important malaria vectors in northern Belize, Central America. Additionally, the impact of outdoor baited traps on mosquito entry into experimental huts was assessed. When operated outside of human-occupied experimental huts, the Centers for Disease Control and Prevention (CDC) miniature light trap, baited with human foot odors, captured significantly greater numbers of female An. albimanus per night (5.1 ± 1.9) than the Biogents Sentinel™ trap baited with BG-Lure™ (1.0 ± 0.2). The 2 trap types captured equivalent numbers of female An. vestitipennis per night, 134.3 ± 45.6 in the CDC trap and 129.6 ± 25.4 in the Sentinel trap. When compared to a matched control hut using no intervention, the use of baited CDC light traps outside an experimental hut did not impact the entry of An. vestitipennis into window interception traps, 17.1 ± 1.3 females per hour in experimental huts vs. 17.2 ± 1.4 females per hour in control huts. However, the use of outdoor baited CDC traps did significantly decrease the entry of An. albimanus into window interception traps from 3.5 ± 0.5 females per hour to 1.9 ± 0.2 females per hour. These results support existing knowledge that the underlying ecological and behavioral tendencies of different Anopheles species can influence trap efficacy. Furthermore, these findings will be used to guide trap selection for future push-pull experiments to be conducted at the study site. PMID:25843092

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

    PubMed

    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. PMID:25294339

  6. Cell Phone-Based System (Chaak) for Surveillance of Immatures of Dengue Virus Mosquito Vectors

    PubMed Central

    LOZANO–FUENTES, SAUL; WEDYAN, FADI; HERNANDEZ–GARCIA, EDGAR; SADHU, DEVADATTA; GHOSH, SUDIPTO; BIEMAN, JAMES M.; TEP-CHEL, DIANA; GARCÍA–REJÓN, JULIÁN E.; EISEN, LARS

    2014-01-01

    Capture of surveillance data on mobile devices and rapid transfer of such data from these devices into an electronic database or data management and decision support systems promote timely data analyses and public health response during disease outbreaks. Mobile data capture is used increasingly for malaria surveillance and holds great promise for surveillance of other neglected tropical diseases. We focused on mosquito-borne dengue, with the primary aims of: 1) developing and field-testing a cell phone-based system (called Chaak) for capture of data relating to the surveillance of the mosquito immature stages, and 2) assessing, in the dengue endemic setting of Mérida, México, the cost-effectiveness of this new technology versus paper-based data collection. Chaak includes a desktop component, where a manager selects premises to be surveyed for mosquito immatures, and a cell phone component, where the surveyor receives the assigned tasks and captures the data. Data collected on the cell phone can be transferred to a central database through different modes of transmission, including near-real time where data are transferred immediately (e.g., over the Internet) or by first storing data on the cell phone for future transmission. Spatial data are handled in a novel, semantically driven, geographic information system. Compared with a pen-and-paper-based method, use of Chaak improved the accuracy and increased the speed of data transcription into an electronic database. The cost-effectiveness of using the Chaak system will depend largely on the up-front cost of purchasing cell phones and the recurring cost of data transfer over a cellular network. PMID:23926788

  7. Replacing a Native Wolbachia with a Novel Strain Results in an Increase in Endosymbiont Load and Resistance to Dengue Virus in a Mosquito Vector

    PubMed Central

    Lu, Peng; Xi, Zhiyong

    2013-01-01

    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. PMID:23755311

  8. Green synthesis of silver nanoparticles for the control of mosquito vectors of malaria, filariasis, and dengue.

    PubMed

    Arjunan, Naresh Kumar; Murugan, Kadarkarai; Rejeeth, Chandrababu; Madhiyazhagan, Pari; Barnard, Donald R

    2012-03-01

    A biological method was used to synthesize stable silver nanoparticles that were tested as mosquito larvicides against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. Annona squamosa leaf broth (5%) reduced aqueous 1 mM AgNO₃ to stable silver nanoparticles with an average size of 450 nm. The structure and percentage of synthesized nanoparticles was characterized by using ultraviolet spectrophotometry, X-Ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy methods. The median lethal concentrations (LC₅₀) of silver nanoparticles that killed fourth instars of Ae. aegypti, Cx. quinquefasciatus, and An. stephensi were 0.30, 0.41, and 2.12 ppm, respectively. Adult longevity (days) in male and female mosquitoes exposed as larvae to 0.1 ppm silver nanoparticles was reduced by ~30% (p<0.05), whereas the number of eggs laid by females exposed as larvae to 0.1 ppm silver nanoparticles decreased by 36% (p<0.05). PMID:22022807

  9. Diversity of Mosquito Vectors (Diptera: Culicidae) in Caxiuanã, Pará, Brazil

    PubMed Central

    Confalonieri, Ulisses E. C.; Costa Neto, Cristina

    2012-01-01

    This paper presents a study based on ecological parameters represented by diversity and richness indices applied in a community of mosquitoes (Diptera: Culicidae), at the National Forest of Caxiuanã, Melgaço municipality, state of Pará, in the Brazilian Amazon. A total of 25,433 specimens of culicids were collected in the study, from five field collection periods, over 10 months, between 2005 and 2006. Specimens were collected in four heights of the forest (ground level, 8 m, 16 m, and 30 m-canopy). Diversity indices of Shannon and Berger-Parker were obtained, and indicators of dominance of species were calculated. The species Culex portesi was dominant in this site, representing about 84% of specimens. Measures of richness and similarity (Jaccard) were obtained for the five strata of time and four height levels. According to the richness estimator abundance-based covered estimator (ACE) the greatest value occurred in April (2006), considering the levels of height to 16 m and on the ground. The estimates obtained have shown quantitative parameters of mosquito populations in the region of the Forest of Caxiuanã. PMID:22997514

  10. Larvicidal and repellent potential of Zingiber nimmonii (J. Graham) Dalzell (Zingiberaceae) essential oil: an eco-friendly tool against malaria, dengue, and lymphatic filariasis mosquito vectors?

    PubMed

    Govindarajan, Marimuthu; Rajeswary, Mohan; Arivoli, Subramanian; Tennyson, Samuel; Benelli, Giovanni

    2016-05-01

    Mosquitoes (Diptera: Culicidae) are important vectors of terms of public health relevance, especially in tropical and sub-tropical regions. The continuous and indiscriminate use of conventional pesticides for the control of mosquito vectors has resulted in the development of resistance and negative impacts on non-target organisms and the environment. Therefore, there is a need for development of effective mosquito control tools. In this study, the larvicidal and repellent activity of Zingiber nimmonii rhizome 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). GC-MS revealed that the Z. nimmonii EO contained at least 33 compounds. Major constituents were myrcene, β-caryophyllene, α-humulene, and α-cadinol. 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 41.19, 44.46, and 48.26 μg/ml, respectively. Repellency bioassays at 1.0, 2.0, and 5.0 mg/cm(2) of Z. nimmonii EO gave 100 % protection up to 120, 150, and 180 min. against An. stephensi, followed by Ae. aegypti (90, 120, and 150 min) and Cx. quinquefasciatus (60, 90, and 120 min). Furthermore, the EO was safer towards two non-target aquatic organisms, Diplonychus indicus and Gambusia affinis, with LC50 values of 3241.53 and 9250.12 μg/ml, respectively. Overall, this research adds basic knowledge to develop newer and safer natural larvicides and repellent from Zingiberaceae plants against malaria, dengue, and filariasis mosquito vectors. PMID:26792432

  11. Entomopathogenic fungi for mosquito control: A review

    PubMed Central

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

    2004-01-01

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

  12. The genetic architecture of a complex trait: Resistance to multiple toxins produced by Bacillus thuringiensis israelensis in the dengue and yellow fever vector, the mosquito Aedes aegypti.

    PubMed

    Bonin, Aurélie; Paris, Margot; Frérot, Hélène; Bianco, Erica; Tetreau, Guillaume; Després, Laurence

    2015-10-01

    The bacterial insecticide Bacillus thuringiensis subsp. israelensis (Bti) is an increasingly popular alternative to chemical insecticides for controlling mosquito populations. Because Bti toxicity relies on the action of four main toxins, resistance to Bti is very likely a complex phenotype involving several genes simultaneously. Dissecting the underlying genetic basis thus requires associating a quantitative measure of resistance to genetic variation at many loci in a segregating population. Here, we undertake this task using the dengue and yellow fever vector, the mosquito Aedes aegypti, as a study model. We conducted QTL (Quantitative Trait Locus) and admixture mapping analyses on two controlled crosses and on an artificial admixed population, respectively, all obtained from resistant and susceptible lab strains. We detected 16 QTL regions, among which four QTLs were revealed by different analysis methods. These four robust QTLs explained altogether 29.2% and 62.2% of the total phenotypic variance in the two QTL crosses, respectively. They also all showed a dominant mode of action. In addition, we found six loci showing statistical association with Bti resistance in the admixed population. Five of the supercontigs highlighted in this study contained candidate genes as suggested by their function, or by prior evidence from expression and/or outlier analyses. These genomic regions are thus good starting points for fine mapping of resistance to Bti or functional analyses aiming at identifying the underlying genes and mutations. Moreover, for the purpose of this work, we built the first Ae. aegypti genetic map based on markers associated with genes expressed in larvae. This genetic map harbors 229 SNP markers mapped across the three chromosomes for a total length of 311.9cM. It brought to light several assembly discrepancies with the reference genome, suggesting a high level of genome plasticity in Ae. aegypti. PMID:26238211

  13. Mosquitocidal properties of Calotropis gigantea (Family: Asclepiadaceae) leaf extract and bacterial insecticide, Bacillus thuringiensis, against the mosquito vectors.

    PubMed

    Kovendan, Kalimuthu; Murugan, Kadarkarai; Prasanna Kumar, Kanagarajan; Panneerselvam, Chellasamy; Mahesh Kumar, Palanisamy; Amerasan, Duraisamy; Subramaniam, Jayapal; Vincent, Savariar

    2012-08-01

    Calotropis gigantea leaf extract and Bacillus thuringiensis were tested first to fourth-instar larvae and pupae of Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. The medicinal plants were collected from the area around Bharathiar University, Coimbatore, India. Calotropis gigantea leaf was washed with tap water and shade-dried at room temperature. An electrical blender powdered the dried plant materials (leaves). The powder 500 g of the leaf was extracted with 1.5 L of organic solvents of methanol for 8 h using a Soxhlet apparatus and filtered. The crude leaf extracts were evaporated to dryness in a rotary vacuum evaporator. The plant extract showed larvicidal and pupicidal effects after 24 h of exposure; no mortality was observed in the control group. For Calotropis gigantea, the median lethal concentration values (LC(50)) observed for the larvicidal and pupicidal activities against mosquito vector species Anopheles stephensi I to IV larval instars and pupae were 73.77, 89.64, 121.69, 155.49, and 213.79 ppm; Aedes aegypti values were 92.27, 106.60, 136.48, 164.01, and 202.56 ppm; and Culex quinquefasciatus values were 104.66, 127.71, 173.75, 251.65, and 314.70 ppm, respectively. For B. thuringiensis, the LC(50) values of I to IV larval instars and pupae of Anopheles stephensi were 37.24, 45.41, 57.82, 80.09, and 98.34 ppm; Aedes aegypti values were 42.38, 51.90, 71.02, 96.17, and 121.59 ppm; and Culex quinquefasciatus values were 55.85, 68.07, 94.11, 113.35, and 133.87 ppm, respectively. The study proved that the methanol leaf extract of Calotropis gigantea and bacterial insecticide B. thuringiensis has mosquitocidal property and was evaluated as target species of mosquito vectors. This is an ideal ecofriendly approach for the control of vector control programs. PMID:22382205

  14. Genetically Modified (GM) Mosquito Use to Reduce Mosquito-Transmitted Disease in the US: A Community Opinion Survey

    PubMed Central

    Adalja, Amesh; Sell, Tara Kirk; McGinty, Meghan; Boddie, Crystal

    2016-01-01

    Introduction: Mosquito-borne infectious diseases such as dengue, chikungunya, and now Zika, pose a public health threat to the US, particularly Florida, the Gulf Coast states, and Hawaii. Recent autochthonous transmission of dengue and chikungunya in Florida, the recent dengue outbreak in Hawaii, and the potential for future local spread of Zika in the US, has led to the consideration of novel approaches to mosquito management. One such novel approach, the release of sterile genetically modified mosquitoes, has been proposed as a possible intervention, and a trial release of GM mosquitoes is being considered in one Florida community. However, this proposal has been controversial. The objective of this research was to increase understanding of community knowledge, attitudes, and beliefs regarding mosquito control and GM mosquitoes.   Methods: An 18-question self-administered survey was mailed to all households in the identified Key West, Florida neighborhood where a GM mosquito trial has been proposed. This survey was fielded between July 20, 2015 and November 1, 2015. The main outcome variable was opposition to the use of GM mosquitoes. Measures included demographic information and opinions on mosquitoes, mosquito control, and vector-borne diseases.   Results: A majority of survey respondents did not support use of GM mosquitoes as a mosquito control method. Discussion: Reasons for opposition included general fears about possible harmful impacts of this intervention, specific worries about human and animal health impacts from the GM mosquitoes, and environmental concerns about potential negative effects on the ecosystem. Residents were more likely to oppose GM mosquito use if they had a low perception of the potential risks posed by diseases like dengue and chikungunya, if they were female, and if they were less concerned about the need to control mosquitoes in general. These findings suggest a need for new approaches to risk communication, including

  15. Biogeography of the two major arbovirus mosquito vectors, Aedes aegypti and Aedes albopictus (Diptera, Culicidae), in Madagascar

    PubMed Central

    2012-01-01

    Background In the past ten years, the Indian Ocean region has been the theatre of severe epidemics of chikungunya and dengue. These outbreaks coincided with a high increase in populations of Aedes albopictus that outcompete its sister taxon Aedes aegypti in most islands sampled. The objective of this work was to update the entomological survey of the two Aedes species in the island of Madagascar which has to face these arboviroses. Methods The sampling of Aedes mosquitoes was conducted during two years, from October 2007 to October 2009, in fifteen localities from eight regions of contrasting climates. Captured adults were identified immediately whereas immature stages were bred until adult stage for determination. Phylogenetic analysis was performed using two mtDNA genes, COI and ND5 and trees were constructed by the maximum likelihood (ML) method with the gene time reversible (GTR) model. Experimental infections with the chikungunya virus strain 06.21 at a titer of 107.5 pfu/mL were performed to evaluate the vector competence of field-collected mosquitoes. Disseminated infection rates were measured fourteen days after infection by immunofluorescence assay performed on head squashes. Results The species Aedes aegypti was detected in only six sites in native forests and natural reserves. In contrast, the species Aedes albopictus was found in 13 out of the 15 sites sampled. Breeding sites were mostly found in man-made environments such as discarded containers, used tires, abandoned buckets, coconuts, and bamboo cuts. Linear regression models showed that the abundance of Ae. albopictus was significantly influenced by the sampling region (F = 62.00, p < 2.2 × 10-16) and period (F = 36.22, p = 2.548 × 10-13), that are associated with ecological and climate variations. Phylogenetic analysis of the invasive Ae. albopictus distinguished haplotypes from South Asia and South America from those of Madagascar, but the markers used were not discriminant enough to discern

  16. Research in mosquito control: current challenges for a brighter future.

    PubMed

    Benelli, Giovanni

    2015-08-01

    Mosquitoes (Diptera: Culicidae) are a key threat for millions of people worldwide, since they act as vectors for devastating pathogens and parasites. In this scenario, vector control is crucial. Mosquito larvae 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. Newer and safer tools have been recently implemented to enhance control of mosquitoes. Here, I focus on some crucial challenges about eco-friendly control of mosquito vectors, mainly the improvement of behavior-based control strategies (sterile insect technique ("SIT") and "boosted SIT") and plant-borne mosquitocidals, including green-synthesized nanoparticles. A number of hot areas that need further research and cooperation among parasitologists, entomologists, and behavioral ecologists are highlighted. PMID:26093499

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

    PubMed Central

    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

  18. Application of polar-orbiting, meteorological satellite data to detect flooding of Rift Valley Fever virus vector mosquito habitats in Kenya.

    PubMed

    Linthicum, K J; Bailey, C L; Tucker, C J; Mitchell, K D; Logan, T M; Davies, F G; Kamau, C W; Thande, P C; Wagateh, J N

    1990-10-01

    Measurements of green-leaf vegetation dynamics recorded by the advanced very high resolution radiometer instruments onboard National Oceanic and Atmospheric Administration satellites 7 and 9 were used to derive ground moisture and rainfall patterns in Kenya and monitor resultant flooding of mosquito larval habitats (dambos) likely to support Rift Valley Fever virus vector mosquitoes (Aedes and Culex spp.). Satellite-derived data from mid-1981 to December 1988 have been analysed with corresponding rainfall, flooding and vector population data as they relate to Rift Valley Fever virus ecology. Single (7 x 7 km) and multiple grid-cell image analysis (200 x 300 km) in small localized areas and large geographical regions, respectively, of vegetation data were used to quantify the potential for flooding of mosquito breeding habitats. The ability to detect accurately parameters, such as ground moisture, that determine flooding could provide local officials with sufficient warning to allow for implementation of specific mosquito control measures before a disease outbreak. PMID:1983457

  19. Molecular basis of odor coding in the malaria vector mosquito Anopheles gambiae

    PubMed Central

    Wang, Guirong; Carey, Allison F.; Carlson, John R.; Zwiebel, Laurence J.

    2010-01-01

    A systematic functional analysis across much of the conventional Anopheles gambiae odorant receptor (AgOR) repertoire was carried out in Xenopus oocytes using two-electrode, voltage-clamp electrophysiology. The resulting data indicate that each AgOR manifests a distinct odor-response profile and tuning breadth. The large diversity of tuning responses ranges from AgORs that are responsive to a single or small number of odorants (specialists) to more broadly tuned receptors (generalists). Several AgORs were identified that respond robustly to a range of human volatiles that may play a critical role in anopheline host selection. AgOR responses were analyzed further by constructing a multidimensional odor space representing the relationships between odorants and AgOR responses. Within this space, the distance between odorants is related to both chemical class and concentration and may correlate with olfactory discrimination. This study provides a comprehensive overview of olfactory coding mechanisms of An. gambiae that ultimately may aid in fostering the design and development of olfactory-based strategies for reducing the transmission of malaria and other mosquito-borne diseases. PMID:20160092

  20. Quantitative trait loci that control vector competence for dengue-2 virus in the mosquito Aedes aegypti.

    PubMed Central

    Bosio, C F; Fulton, R E; Salasek, M L; Beaty, B J; Black, W C

    2000-01-01

    Quantitative trait loci (QTL) affecting the ability of the mosquito Aedes aegypti to become infected with dengue-2 virus were mapped in an F(1) intercross. Dengue-susceptible A. aegypti aegypti were crossed with dengue refractory A. aegypti formosus. F(2) offspring were analyzed for midgut infection and escape barriers. In P(1) and F(1) parents and in 207 F(2) individuals, regions of 14 cDNA loci were analyzed with single-strand conformation polymorphism analysis to identify and orient linkage groups with respect to chromosomes I-III. Genotypes were also scored at 57 RAPD-SSCP loci, 5 (TAG)(n) microsatellite loci, and 6 sequence-tagged RAPD loci. Dengue infection phenotypes were scored in 86 F(2) females. Two QTL for a midgut infection barrier were detected with standard and composite interval mapping on chromosomes II and III that accounted for approximately 30% of the phenotypic variance (sigma(2)(p)) in dengue infection and these accounted for 44 and 56%, respectively, of the overall genetic variance (sigma(2)(g)). QTL of minor effect were detected on chromosomes I and III, but these were not detected with composite interval mapping. Evidence for a QTL for midgut escape barrier was detected with standard interval mapping but not with composite interval mapping on chromosome III. PMID:11014816

  1. The role of male harassment on female fitness for the dengue vector mosquito Aedes aegypti

    PubMed Central

    Helinski, Michelle E.H.; Harrington, Laura C.

    2014-01-01

    Sexual harassment studies in insects suggest that females can incur several kinds of costs from male harassment and mating. Here, we examined direct and indirect costs of male harassment on components of female fitness in the predominantly monandrous mosquito Aedes aegypti. To disentangle the costs of harassment versus the costs of mating, we held females at a low or high density with males whose claspers were modified to prevent insemination, and compared these to females held with normal males and to those held with females or alone. A reduced longevity was observed when females were held under high density conditions with males or females, regardless if male claspers had been modified. There was no consistent effect of harassment on female fecundity. Net reproductive rate (R0) was higher in females held at low density with normal males compared to females held with males in the other treatments, even though only a small number of females showed direct evidence of remating. Indirect costs and benefits that were not due to harassment alone were observed. Daughters of females held with normal males at high density had reduced longevity compared to daughters from females held without conspecifics. However, their fitness (R0) was higher compared to females in all other treatments. Overall, our results indicate that A. aegypti females do not suffer a fitness cost from harassment of males when kept at moderate densities, and they suggest the potential for benefits obtained from ejaculate components. PMID:25544799

  2. First molecular identification of Dirofilaria spp. (Onchocercidae) in mosquitoes from Serbia.

    PubMed

    Kurucz, Kornélia; Kepner, Anett; Krtinic, Bosiljka; Zana, Brigitta; Földes, Fanni; Bányai, Krisztián; Oldal, Miklós; Jakab, Ferenc; Kemenesi, Gábor

    2016-08-01

    Dirofilariosis is a common and widespread veterinary health issue in several European countries with notable zoonotic potential. The causative agents are Dirofilaria immitis and Dirofilaria repens nematoda species which are transmitted by different mosquito vectors. Similar to other mosquito-borne infections, the knowledge about mosquito species involved in disease transmission is crucial for the complex understanding of local transmission cycles. Since there is no available data on mosquito species, potentially involved in disease transmission from Serbia, 6369 female mosquito individuals were retrospectively tested for Dirofilaria nematodes, collected from 13 localities in Vojvodina province, Serbia, in 2013. Altogether, 8.33 % of tested pools showed positivity, composed of five mosquito species, mainly, Culex pipiens and Aedes vexans. D. immitis and D. repens were both detected from multiple localities, during the whole period of mosquito breeding season, which provides the first data on local transmission characteristics regarding mosquitoes from the Balkans. PMID:27193348

  3. A new species of Hepatozoon (Apicomplexa: Adeleorina) from Python regius (Serpentes: Pythonidae) and its experimental transmission by a mosquito vector.

    PubMed

    Sloboda, Michal; Kamler, Martin; Bulantová, Jana; Votýpka, Jan; Modrý, David

    2007-10-01

    Hepatozoon ayorgbor n. sp. is described from specimens of Python regius imported from Ghana. Gametocytes were found in the peripheral blood of 43 of 55 snakes examined. Localization of gametocytes was mainly inside the erythrocytes; free gametocytes were found in 15 (34.9%) positive specimens. Infections of laboratory-reared Culex quinquefasciatus feeding on infected snakes, as well as experimental infection of juvenile Python regius by ingestion of infected mosquitoes, were performed to complete the life cycle. Similarly, transmission to different snake species (Boa constrictor and Lamprophis fuliginosus) and lizards (Lepidodactylus lugubris) was performed to assess the host specificity. Isolates were compared with Hepatozoon species from sub-Saharan reptiles and described as a new species based on the morphology, phylogenetic analysis, and a complete life cycle. PMID:18163356

  4. Anti-mosquito plants as an alternative or incremental method for malaria vector control among rural communities of Bagamoyo District, Tanzania

    PubMed Central

    2014-01-01

    insect control. Conclusion This survey has indicated some knowledge gap among community members in managing mosquito vectors using plant. The communities need a basic health education and sensitization for effective exploitation of this valuable tool for reducing mosquitoes and associated disease burdens. On the other hand, the government of Tanzania should strengthen advocacy of botanical pesticides development, registration and regulation for public health benefits because they are source of pest control tools people rely on them. PMID:25015092

  5. Identification of a major Quantitative Trait Locus determining resistance to the organophosphate temephos in the dengue vector mosquito Aedes aegypti.

    PubMed

    Paiva, Marcelo H S; Lovin, Diane D; Mori, Akio; Melo-Santos, Maria A V; Severson, David W; Ayres, Constância F J

    2016-01-01

    Organophosphate insecticides (OP) have extensively been used to control mosquitoes, such as the vector Aedes aegypti. Unfortunately, OP resistance has hampered control programs worldwide. We used Quantitative Trait Locus (QTL) mapping to evaluate temephos resistance in two F1 intercross populations derived from crosses between a resistant Ae. aegypti strain (RecR) and two susceptible strains (MoyoD and Red). A single major effect QTL was identified on chromosome 2 of both segregating populations, named rtt1 (resistance to temephos 1). Bioinformatics analyses identified a cluster of carboxylesterase genes (CCE) within the rtt1 interval. qRT-PCR demonstrated that different CCEs were up-regulated in F2 resistant individuals from both crosses. However, none exceeded the 2-fold expression. Primary mechanisms for temephos resistance may vary between Ae. aegypti populations, yet also appear to support previous findings suggesting that multiple linked esterase genes may contribute to temephos resistance in the RecR strain as well as other populations. PMID:26576515

  6. Genetic Diversity and Phylogeny of Aedes aegypti, the Main Arbovirus Vector in the Pacific

    PubMed Central

    Calvez, Elodie; Guillaumot, Laurent; Millet, Laurent; Marie, Jérôme; Bossin, Hervé; Rama, Vineshwaran; Faamoe, Akata; Kilama, Sosiasi; Teurlai, Magali; Mathieu-Daudé, Françoise; Dupont-Rouzeyrol, Myrielle

    2016-01-01

    Background The Pacific region is an area unique in the world, composed of thousands of islands with differing climates and environments. The spreading and establishment of the mosquito Aedes aegypti in these islands might be linked to human migration. Ae. aegypti is the major vector of arboviruses (dengue, chikungunya and Zika viruses) in the region. The intense circulation of these viruses in the Pacific during the last decade led to an increase of vector control measures by local health authorities. The aim of this study is to analyze the genetic relationships among Ae. aegypti populations in this region. Methodology/Principal Finding We studied the genetic variability and population genetics of 270 Ae. aegypti, sampled from 9 locations in New Caledonia, Fiji, Tonga and French Polynesia by analyzing nine microsatellites and two mitochondrial DNA regions (CO1 and ND4). Microsatellite markers revealed heterogeneity in the genetic structure between the western, central and eastern Pacific island countries. The microsatellite markers indicate a statistically moderate differentiation (FST = 0.136; P < = 0.001) in relation to island isolation. A high degree of mixed ancestry can be observed in the most important towns (e.g. Noumea, Suva and Papeete) compared with the most isolated islands (e.g. Ouvea and Vaitahu). Phylogenetic analysis indicated that most of samples are related to Asian and American specimens. Conclusions/Significance Our results suggest a link between human migrations in the Pacific region and the origin of Ae. aegypti populations. The genetic pattern observed might be linked to the island isolation and to the different environmental conditions or ecosystems. PMID:26799213

  7. Determinants of the population growth of the West Nile virus mosquito vector Culex pipiens in a repeatedly affected area in Italy

    PubMed Central

    2014-01-01

    Background The recent spread of West Nile Virus in temperate countries has raised concern. Predicting the likelihood of transmission is crucial to ascertain the threat to Public and Veterinary Health. However, accurate models of West Nile Virus (WNV) expansion in Europe may be hampered by limited understanding of the population dynamics of their primary mosquito vectors and their response to environmental changes. Methods We used data collected in north-eastern Italy (2009–2011) to analyze the determinants of the population growth rate of the primary WNV vector Culex pipiens. A series of alternative growth models were fitted to longitudinal data on mosquito abundance to evaluate the strength of evidence for regulation by intrinsic density-dependent and/or extrinsic environmental factors. Model-averaging algorithms were then used to estimate the relative importance of intrinsic and extrinsic variables in describing the variations of per-capita growth rates. Results Results indicate a much greater contribution of density-dependence in regulating vector population growth rates than of any environmental factor on its own. Analysis of an average model of Cx. pipiens growth revealed that the most significant predictors of their population dynamics was the length of daylight, estimated population size and temperature conditions in the 15 day period prior to sampling. Other extrinsic variables (including measures of precipitation, number of rainy days, and humidity) had only a minor influence on Cx. pipiens growth rates. Conclusions These results indicate the need to incorporate density dependence in combination with key environmental factors for robust prediction of Cx. pipiens population expansion and WNV transmission risk. We hypothesize that detailed analysis of the determinants of mosquito vector growth rate as conducted here can help identify when and where an increase in vector population size and associated WNV transmission risk should be expected. PMID:24428887

  8. Chemical composition and larvicidal activity of the essential oil of Plectranthus amboinicus (Lour.) Spreng against Anopheles stephensi: a malarial vector mosquito.

    PubMed

    Senthilkumar, Annadurai; Venkatesalu, Venugopalan

    2010-10-01

    Essential oil of Plectranthus amboinicus was studied for its chemical composition and larvicidal potential against the malarial vector mosquito Anopheles stephensi. Totally 26 compounds were identified by GC and GC-MS. The major chemical compounds were carvacrol (28.65%) followed by thymol (21.66%), α-humulene (9.67%), undecanal (8.29%), γ-terpinene (7.76%), ρ-cymene (6.46%), caryophyllene oxide (5.85%), α-terpineol (3.28%) and β-selinene (2.01%). The larvicidal assay was conducted to record the LC(50) and LC(90) values and the larval mortality was observed after 12 and 24 h of exposure period. The LC(50) values of the oil were 33.54 (after 12 h) and 28.37 ppm (after 24 h). The LC(90) values of the oil were 70.27 (after 12 h) and 59.38 ppm (after 24 h). The results of the present study showed that the essential oil of P. amboinicus is one of the inexpensive and eco-friendly sources of natural mosquito larvicidal agent to control/reduce the population of malarial vector mosquito. PMID:20668876

  9. Lethal Effects of Aspergillus niger against Mosquitoes Vector of Filaria, Malaria, and Dengue: A Liquid Mycoadulticide

    PubMed Central

    Singh, Gavendra; Prakash, Soam

    2012-01-01

    Aspergillus niger is a fungus of the genus Aspergillus. It has caused a disease called black mold on certain fruits and vegetables. The culture filtrates released from the A. niger ATCC 66566 were grown in Czapek dox broth (CDB) then filtered with flash chromatograph and were used for the bioassay after a growth of thirty days. The result demonstrated these mortalities with LC50, LC90, and LC99 values of Culex quinquefasciatus 0.76, 3.06, and 4.75, Anopheles stephensi 1.43, 3.2, and 3.86, and Aedes aegypti 1.43, 2.2, and 4.1 μl/cm2, after exposure of seven hours. We have calculated significant LT90 values of Cx. quinquefasciatus 4.5, An. stephensi 3.54, and Ae. aegypti 6.0 hrs, respectively. This liquid spray of fungal culture isolate of A. niger can reduce malaria, dengue, and filarial transmission. These results significantly support broadening the current vector control paradigm beyond chemical adulticides. PMID:22629156

  10. Aromatic plant-derived essential oil: an alternative larvicide for mosquito control.

    PubMed

    Pitasawat, B; Champakaew, D; Choochote, W; Jitpakdi, A; Chaithong, U; Kanjanapothi, D; Rattanachanpichai, E; Tippawangkosol, P; Riyong, D; Tuetun, B; Chaiyasit, D

    2007-04-01

    Five aromatic plants, Carum carvi (caraway), Apium graveolens (celery), Foeniculum vulgare (fennel), Zanthoxylum limonella (mullilam) and Curcuma zedoaria (zedoary) were selected for investigating larvicidal potential against mosquito vectors. Two laboratory-reared mosquito species, Anopheles dirus, the major malaria vector in Thailand, and Aedes aegypti, the main vector of dengue and dengue hemorrhagic fever in urban areas, were used. All of the volatile oils exerted significant larvicidal activity against the two mosquito species after 24-h exposure. Essential oil from mullilam was the most effective against the larvae of A. aegypti, while A. dirus larvae showed the highest susceptibility to zedoary oil. PMID:17337133

  11. Mosquito Immunity against Arboviruses

    PubMed Central

    Sim, Shuzhen; Jupatanakul, Natapong; Dimopoulos, George

    2014-01-01

    Arthropod-borne viruses (arboviruses) pose a significant threat to global health, causing human disease with increasing geographic range and severity. The recent availability of the genome sequences of medically important mosquito species has kick-started investigations into the molecular basis of how mosquito vectors control arbovirus infection. Here, we discuss recent findings concerning the role of the mosquito immune system in antiviral defense, interactions between arboviruses and fundamental cellular processes such as apoptosis and autophagy, and arboviral suppression of mosquito defense mechanisms. This knowledge provides insights into co-evolutionary processes between vector and virus and also lays the groundwork for the development of novel arbovirus control strategies that target the mosquito vector. PMID:25415198

  12. Larvicidal activity of selected plant hydrodistillate extracts against the house mosquito, Culex pipiens, a West Nile virus vector.

    PubMed

    Cetin, Huseyin; Yanikoglu, Atila; Cilek, James E

    2011-04-01

    The larvicidal activity of hydrodistillate extracts from Chrysanthemum coronarium L., Hypericum scabrum L., Pistacia terebinthus L. subsp. palaestina (Boiss.) Engler, and Vitex agnus castus L. was investigated against the West Nile vector, Culex pipiens L. (Diptera: Culicidae). Yield and identification of the major essential oils from each distillation was determined by GC-MS analyses. The major essential oil component for each plant species was as follows: α-pinene for P. terebinthus palaestina, and H. scabrum (45.3% and 42.3%, respectively), trans-β-caryophyllene for V. agnus castus (22.1%), and borneol for C. coronarium (20.9%). A series of distillate concentrations from these plants (that ranged from 1 ppm to 500 ppm, depending on plant species) were assessed against late third to early fourth C. pipiens larvae at 1, 6, and 24 h posttreatment. In general, larval mortality to water treated with a distillate increased as concentration and exposure time increased. H. scabrum and P. terebinthus palaestina were most effective against the mosquito larvae and both produced 100% mortality at 250 ppm at 24-h continuous exposure compared with the other plant species. Larval toxicity of the distillates at 24 h (LC(50) from most toxic to less toxic) was as follows: P. terebinthus palaestina (59.2 ppm) > H. scabrum (82.2 ppm) > V. agnus castus (83.3 ppm) > C. coronarium (311.2 ppm). But when LC(90) values were compared, relative toxicity ranking changed as follows: H. scabrum (185.9 ppm) > V. agnus castus (220.7 ppm) > P. terebinthus palaestina (260.7 ppm) > C. coronarium (496.3 ppm). Extracts of native Turkish plants continue to provide a wealth of potential sources for biologically active agents that may be applied against arthropod pests of man and animals. PMID:21053014

  13. Eugenol, α-pinene and β-caryophyllene from Plectranthus barbatus essential oil as eco-friendly larvicides against malaria, dengue and Japanese encephalitis mosquito vectors.

    PubMed

    Govindarajan, Marimuthu; Rajeswary, Mohan; Hoti, S L; Bhattacharyya, Atanu; Benelli, Giovanni

    2016-02-01

    Mosquito-borne diseases represent a deadly threat for millions of people worldwide. Eco-friendly mosquitocides are a priority. In Ayurvedic medicine, Plectranthus species have been used to treat heart disease, convulsions, spasmodic pain and painful urination. In this research, we evaluated the acute toxicity of essential oil from Plectranthus barbatus and its major constituents, against larvae of the malaria vector Anopheles subpictus, the dengue vector Aedes albopictus and the Japanese encephalitis vector Culex tritaeniorhynchus. The chemical composition of P. barbatus essential oil was analyzed by gas chromatography-mass spectroscopy. Nineteen components were identified. Major constituents were eugenol (31.12%), α-pinene (19.38%) and β-caryophyllene (18.42%). Acute toxicity against early third-instar larvae of An. subpictus, Ae. albopictus and Cx. tritaeniorhynchus was investigated. The essential oil had a significant toxic effect against larvae of An. subpictus, Ae. albopictus and Cx. tritaeniorhynchus, with 50% lethal concentration (LC50) values of 84.20, 87.25 and 94.34 μg/ml and 90% lethal concentration (LC90) values of 165.25, 170.56 and 179.58 μg/ml, respectively. Concerning major constituents, eugenol, α-pinene and β-caryophyllene appeared to be most effective against An. subpictus (LC50 = 25.45, 32.09 and 41.66 μg/ml, respectively), followed by Ae. albopictus (LC50 = 28.14, 34.09 and 44.77 μg/ml, respectively) and Cx. tritaeniorhynchus (LC50 = 30.80, 36.75 and 48.17 μg/ml, respectively). Overall, the chance to use metabolites from P. barbatus essential oil against mosquito vectors seems promising, since they are effective at low doses and could be an advantageous alternative to build newer and safer mosquito control tools. PMID:26518773

  14. Chitosan/siRNA nanoparticle targeting demonstrates a requirement for single-minded during larval and pupal olfactory system development of the vector mosquito Aedes aegypti

    PubMed Central

    2014-01-01

    Background Essentially nothing is known about the genetic regulation of olfactory system development in vector mosquitoes, which use olfactory cues to detect blood meal hosts. Studies in Drosophila melanogaster have identified a regulatory matrix of transcription factors that controls pupal/adult odorant receptor (OR) gene expression in olfactory receptor neurons (ORNs). However, it is unclear if transcription factors that function in the D. melanogaster regulatory matrix are required for OR expression in mosquitoes. Furthermore, the regulation of OR expression during development of the larval olfactory system, which is far less complex than that of pupae/adults, is not well understood in any insect, including D. melanogaster. Here, we examine the regulation of OR expression in the developing larval olfactory system of Aedes aegypti, the dengue vector mosquito. Results A. aegypti bears orthologs of eight transcription factors that regulate OR expression in D. melanogaster pupae/adults. These transcription factors are expressed in A. aegypti larval antennal sensory neurons, and consensus binding sites for these transcription factors reside in the 5’ flanking regions of A. aegypti OR genes. Consensus binding sites for Single-minded (Sim) are located adjacent to over half the A. aegypti OR genes, suggesting that this transcription factor functions as a major regulator of mosquito OR expression. To functionally test this hypothesis, chitosan/siRNA nanoparticles were used to target sim during larval olfactory development. These experiments demonstrated that Sim positively regulates expression of a large subset of OR genes, including orco, the obligate co-receptor in the assembly and function of heteromeric OR/Orco complexes. Decreased innervation of the antennal lobe was also noted in sim knockdown larvae. These OR expression and antennal lobe defects correlated with a larval odorant tracking behavioral defect. OR expression and antennal lobe defects were also

  15. Investigating the Potential Range Expansion of the Vector Mosquito Aedes Aegypti in Mexico with NASA Earth Science Remote Sensing Results

    NASA Technical Reports Server (NTRS)

    Estes, Sue M.

    2011-01-01

    Dengue (Breakbone) fever is caused by one of four viruses carried by mosquitoes in tropical and subtropical areas. Cases have increased dramatically in the past few decades; there are currently approximately 100 million infections annually around the globe. Our project will integrate environmental observations, including weather, land use, vegetation type, amount and greenness, soil moisture, and mosquito populations with investigations of the human dynamics of the system via household surveys.

  16. Disruptive technology for vector control: the Innovative Vector Control Consortium and the US Military join forces to explore transformative insecticide application technology for mosquito control programmes.

    PubMed

    Knapp, Jennifer; Macdonald, Michael; Malone, David; Hamon, Nicholas; Richardson, Jason H

    2015-01-01

    Malaria vector control technology has remained largely static for decades and there is a pressing need for innovative control tools and methodology to radically improve the quality and efficiency of current vector control practices. This report summarizes a workshop jointly organized by the Innovative Vector Control Consortium (IVCC) and the Armed Forces Pest Management Board (AFPMB) focused on public health pesticide application technology. Three main topics were discussed: the limitations with current tools and techniques used for indoor residual spraying (IRS), technology innovation to improve efficacy of IRS programmes, and truly disruptive application technology beyond IRS. The group identified several opportunities to improve application technology to include: insuring all IRS programmes are using constant flow valves and erosion resistant tips; introducing compression sprayer improvements that help minimize pesticide waste and human error; and moving beyond IRS by embracing the potential for new larval source management techniques and next generation technology such as unmanned "smart" spray systems. The meeting served to lay the foundation for broader collaboration between the IVCC and AFPMB and partners in industry, the World Health Organization, the Bill and Melinda Gates Foundation and others. PMID:26409879

  17. Vertical oviposition activity of mosquitoes in the Atlantic Forest of Brazil with emphasis on the sylvan vector, Haemagogus leucocelaenus (Diptera: Culicidae).

    PubMed

    Alencar, Jeronimo; de Mello, Cecilia Ferreira; Gil-Santana, Hélcio R; Guimarães, Anthony Érico; de Almeida, Sergio Antonio Silva; Gleiser, Raquel M

    2016-06-01

    This study aimed to assess the vertical patterns of oviposition and temporal changes in the distribution of mosquito species in an area of the Atlantic Forest in Rio de Janeiro State, Brazil, and in particular, the behavior and oviposition of potential yellow fever virus vectors. Mosquito samples were collected from the Ecological Reserve Guapiaçu (REGUA, Brazil), which includes a somewhat disturbed forest, with a large diversity of plants and animals. In all, 5,458 specimens (ten species from seven genera) were collected. Haemagogus leucocelaenus was the most frequently captured species, representing 73% of the specimens collected. Species richness and diversity were the highest in the samples collected from the ground-level ovitraps and decreased with height. Species composition also differed significantly among heights. The largest species differences were detected between ovitraps set at the ground level and those set at 7 m and 9 m; Hg. leucocelaenus, Limatus durhamii, and Limatus paraensis contributed most to these differences. Sampling month and climatic variables had significant effects on species richness and diversity. Species diversity and richness decreased with height, suggesting that the conditions for mosquito breeding are more favorable closer to the ground. Species composition also showed vertical differences. PMID:27232120

  18. An ace-1 gene duplication resorbs the fitness cost associated with resistance in Anopheles gambiae, the main malaria mosquito

    PubMed Central

    Assogba, Benoît S.; Djogbénou, Luc S.; Milesi, Pascal; Berthomieu, Arnaud; Perez, Julie; Ayala, Diego; Chandre, Fabrice; Makoutodé, Michel; Labbé, Pierrick; Weill, Mylène

    2015-01-01

    Widespread resistance to pyrethroids threatens malaria control in Africa. Consequently, several countries switched to carbamates and organophophates insecticides for indoor residual spraying. However, a mutation in the ace-1 gene conferring resistance to these compounds (ace-1R allele), is already present. Furthermore, a duplicated allele (ace-1D) recently appeared; characterizing its selective advantage is mandatory to evaluate the threat. Our data revealed that a unique duplication event, pairing a susceptible and a resistant copy of the ace-1 gene spread through West Africa. Further investigations revealed that, while ace-1D confers less resistance than ace-1R, the high fitness cost associated with ace-1R is almost completely suppressed by the duplication for all traits studied. ace-1 duplication thus represents a permanent heterozygote phenotype, selected, and thus spreading, due to the mosaic nature of mosquito control. It provides malaria mosquito with a new evolutionary path that could hamper resistance management. PMID:26434951

  19. Laboratory Evaluations of the Fractions Efficacy of Annona senegalensis (Annonaceae) Leaf Extract on Immature Stage Development of Malarial and Filarial Mosquito Vectors

    PubMed Central

    Lame, Younoussa; Nukenine, Elias Nchiwan; Pierre, Danga Yinyang Simon; Elijah, Ajaegbu Eze; Esimone, Charles Okechukwu

    2015-01-01

    Background: Within the framework to control mosquitoes, ovicidal, larvicidal and pupicidal activity of Annona senegalensis leaf extract and its 4 fractions against Anopheles gambiae and Culex quinquefasciatus were evaluated in the laboratory conditions. Methods: Ovicidal test was performed by submitting at least 100 eggs of mosquitoes to 125, 250, 500, 1000 and 2000 ppm concentrations, while larvicidal and pupicidal effects were assessed by submitting 25 larvae or pupae to the concentrations of 2500, 1250, 625 and 312.5 ppm of plant extract or fractions of A. senegalensis. Results: The eggs of An. gambiae were most affected by N-hexane (0.00% hatchability) and chloroform (03.67% hatchability) fractions compared to Cx. quinquefasciatus where at least 25 % hatchability were recorded at 2000 ppm. For larvicidal test, N-hexane (LC50= 298.8 ppm) and chloroform (LC50= 418.3 ppm) fractions were more effective than other fractions on An. gambiae larvae while, a moderate effectiveness was also observed with N-hexane (LC50= 2087.6 ppm), chloroform (LC50= 9010.1 ppm) fractions on Cx. quinquefasciatus larvae. The highest mortality percent of the pupae were also recorded with N-hexane and chloroform fractions on An. gambiae at 2500 ppm. As for Cx. quinquefasciatus only 50 % and 36 % mortality were recorded with N-hexane and chloroform fractions respectively. Conclusion: The extract of A. senegalensis was toxic on immature stage of mosquito species tested. By splitting methanolic crude extract, only N-hexane and chloroform fractions were revealed to possess a mosquitocidal effects and could be considered and utilized for future immature mosquito vectors control. PMID:26623434

  20. One-pot biogenic fabrication of silver nanocrystals using Quisqualis indica: Effectiveness on malaria and Zika virus mosquito vectors, and impact on non-target aquatic organisms.

    PubMed

    Govindarajan, Marimuthu; Vijayan, Periasamy; Kadaikunnan, Shine; Alharbi, Naiyf S; Benelli, Giovanni

    2016-09-01

    Currently, mosquito vector control is facing a number of key challenges, including the rapid development of resistance to synthetic pesticides and the recent spread of aggressive arbovirus outbreaks. The biosynthesis of silver nanoparticles (AgNPs) is currently considered an environmental friendly alternative to the employ of pyrethroids, carbamates and microbial agents (e.g. Bacillus thuringiensis var. israelensis), since AgNPs are easy to produce, effective and stable in the aquatic environment. However, their biophysical features showed wide variations according to the botanical agent using for the green synthesis, outlining the importance of screening local floral resources used as reducing and stabilizing agents. In this study, we focused on the biophysical properties and the mosquitocidal action of Quisqualis indica-fabricated AgNPs. AgNPs were characterized using spectroscopic (UV, FTIR, XRD) and microscopic (AFM, SEM, TEM and EDX) techniques. AFM, SEM and TEM confirmed the synthesis of poly-dispersed AgNPs with spherical shape and size ranging from 1 to 30nm. XRD shed light on the crystalline structure of these AgNPs. The acute toxicity of Quisqualis indica extract and AgNPs was evaluated against malaria, arbovirus, and filariasis vectors, Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus, as well as on three important non-target aquatic organisms. The Q. indica leaf extract showed moderate larvicidal effectiveness on Cx. quinquefasciatus (LC50=220.42), Ae. aegypti (LC50=203.63) and An. stephensi (LC50=185.98). Q. indica-fabricated AgNPs showed high toxicity against Cx. quinquefasciatus (LC50=14.63), Ae. aegypti (LC50=13.55) and An. stephensi (LC50=12.52), respectively. Notably, Q. indica-synthesized AgNPs were moderately toxic to non-target aquatic mosquito predators Anisops bouvieri (LC50=653.05μg/mL), Diplonychus indicus (LC50=860.94μg/mL) and Gambusia affinis (LC50=2183.16μg/mL), if compared to the targeted mosquitoes. Overall, the

  1. Spectral and HRTEM analyses of Annona muricata leaf extract mediated silver nanoparticles and its Larvicidal efficacy against three mosquito vectors Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti.

    PubMed

    Santhosh, Shanthi Bhupathi; Ragavendran, Chinnasamy; Natarajan, Devarajan

    2015-12-01

    Mosquitoes transmit various diseases which mainly affect the human beings and every year cause millions of deaths globally. Currently available chemical and synthetic mosquitocidal agents pose severe side effects, pollute the environment vigorously, and become resistance. There is an urgent need to identify and develop the cost effective, compatible and eco-friendly product for mosquito control. The present study was aimed to find out the larvicidal potential of aqueous crude extract and green synthesized silver nanoparticles (AgNPs) from Annona muricata leaves were tested against fourth instar larvae of three important mosquitoes i.e. Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti using different concentrations of AgNPs (10, 20, 30, 40 and 50 ppm) and the aqueous leaf extract (100, 200, 300, 400, and 500 ppm) for 24 and 48 h. The maximum mortality was noticed in AgNPs than aqueous leaf extract of A. muricata against tested mosquitoes with least LC50 values of 37.70, 31.29, and 20.65 ppm (24h) and 546.7, 516.2, and 618.4 ppm (48 h), respectively. All tested concentrations of AgNps exhibited 100% mortality in A. aegypti larvae at 48 hour observation. In addition, the plant mediated AgNPs were characterized by UV-vis spectrum, Fourier transform infrared spectroscopy, particle size analyser, X-ray diffraction, high resonance transmission electron microscopy, and energy-dispersive X-ray spectroscopy analysis for confirmation of nanoparticle synthesis. Based on the findings of the study suggests that the use of A. muricata plant mediated AgNPs can act as an alternate insecticidal agents for controlling target mosquitoes. PMID:26410042

  2. Understanding the spatial and temporal distribution of potential mosquito vectors of Rift Valley fever in the U.S.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever (RVF) is a mosquito-borne zoonotic hemorrhagic viral disease confined primarily to sub-Saharan Africa. In RVF endemic regions human and livestock populations suffer prominent health and economic impacts during RVF outbreaks. RVF virus is listed as an overlap Select Agent by both ...

  3. REPELLENT EFFECT OF OCIMUM BASILICUM AND GLYCYRRHIZA GLABRA EXTRACTS AGAINST THE MOSQUITO VECTOR, CULEX PIPIENS (DIPTERA: CULICIDAE).

    PubMed

    Hassan, Mostafa I; Hammad, Kotb M; Saeed, Saeed M

    2015-08-01

    Essential or volatile oils of plants have been variously reported to have many medicinal applications. Methanol, acetone and petroleum ether extracts of Ocimum basilicum and Glycyrrhiza glabra were screened for their repellency effect against Culex pipiens mosquito. The repellent action of the present plants extracts were varied depending on the solvent used and dose of extract. Methanol extract of O. basilicum exhibited the lowest repellent activity as it recorded 77.4% at 6.7mg/cm2. The petroleum ether and acetone extract of 0. basilicum showed repellency of 98.1 & 84.6% respectively, at dose of 6.7mg/cm2, while methanolic extract of G. glabra recorded 73.8 & 50.3% at dose of 6.7 &1.7mg/cm2 respectively, the petroleum ether and acetone extract of G. glabra showed repellency of 76.3 & 81.6%, respectively at dose of 6.7mg/cm2, compared with the commercial formulation, N.N. diethyl toulamide (DEET) which exhibited 100% repellent action at dose of 1.8mg/cm2, respectively. The results may contribute to design an alternative way to control mosquitoes currently based on applications of synthetic insecticides. These extracts could be developed commercially as an effective personal protection meaure against mosquito bites and thus to control diseases caused by mosquito-borne pathogens. PMID:26485843

  4. Novel tests for rapid detection of insecticide resistance in mosquito vectors. Annual report, 15 June 1986-14 June 1987

    SciTech Connect

    Georghiou, G.P.

    1987-07-01

    During this project, priority was given to research on the formulation of simple diagnostic tests for the detection of organophosphate (OP) resistance in individual mosquitoes. Emphasis was placed on the mechanisms of insensitive acetycholinesterase and of detoxification of OP's by esterases.

  5. Use of Remote Sensing Surveillance to Monitor Environmental Parameters Associated with Mosquito Abundance and Vector-borne Diseases

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Lymphatic filariasis persists as a major cause of clinical morbidity and a significant impediment to socioeconomic development in various parts of the world including Egypt. In Egypt, filariasis has been endemic since time immemorial. Early epidemiologic studies identified Culex pipiens L. as the main vector of the disease and also showed that the geographic distribution of the disease is highly focal and concentrated in lower Egypt. Between 1950 and 1965, a large scale filariasis control program was carried out by the Egyptian Ministry of Health (EMOH) in the endemic areas. Control efforts led to a steady decrease of the disease in areas of the country previously identified as endemic. However, spot surveys conducted in various parts of the Nile Delta during the 1970's and 1980's revealed that the downward trend of the disease had stopped and that the prevalence and intensity of microfilaraemia had increased.

  6. Larvicidal activity of the extracts from different parts of the plant Solanum xanthocarpum against important mosquito vectors in the arid region.

    PubMed

    Bansal, S K; Singh, Karam V; Kumar, Suresh

    2009-03-01

    Larvicidal efficacy of the aqueous and methanol extracts from green unripe and yellow ripe fruits, seeds, leaves and roots of the plant Solanum xanthocarpum was evaluated against Anopheles culicifacies, Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus, the important mosquito vectors prevalent in the arid region. Studies were carried out on late 3rd orearly 4th instarlarvae of these species using standard WHO technique. Based on concentration mortality data LC50 and LC90 values along with their fiducial limits, regression equation, chi-square (chi2)/heterogeneity of the response have been determined bylog probit regression analysis. The 24 hr LC50 values as observed for aqueous extracts for green unripe and yellow ripe fruits were 112.7, 498.2 and 846.3 mg l(-1) and 104.7, 267.7and 832.2 mg l(-1) for Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus respectively. However, the 24 hr LC50 values formethanol extracts of yellow ripe fruits and seeds were 51.6, 52.2, 118.3 and 157.1 mg l(-1) and 66.9, 73.7, 123.8 and 154.9 mg l(-1) for the above four vector species respectively. The results showed that larvae of anophelines were much more susceptible as compared to culicines to both the aqueous and methanol extracts from fruits and seeds of the plant tested. The methanol extracts were found 2-5 times more effective as compared to the aqueous extracts. The chi-square values calculated during the analysis did not show any heterogeneity of the response. Experiments conducted with aqueous and methanol extracts from leaves and roots of this plant species didn't show any larvicidal activity against any of the mosquito species tested. The study would be of great importance while formulating vector control strategy based on alternative plant based insecticides. PMID:20121022

  7. Laboratory and field trial of developing medicinal local Thai plant products against four species of mosquito vectors.

    PubMed

    Trongtokit, Yuwadee; Rongsriyam, Yupha; Komalamisra, Narumon; Krisadaphong, Panvipa; Apiwathnasorn, Chamnarn

    2004-06-01

    Oils of Syzygium aromaticum (clove) and Zanthoxylum limonella (makaen), widely used essential oils for dental caries or flavoring of food in Thailand, were prepared as 10 experimental repellent products in gel or cream form against Aedes aegypti, Culex quinquefasciatus, and Anopheles dirus under laboratory conditions, using the human-arm-in-cage method. Two products that gave the longest-lasting complete protection were selected to examine their repellency against a variety of mosquito species under field conditions. In laboratory tests, 0.1 g of each product was applied to 3x10 cm of exposed area on a volunteer's forearm, while in field trials, 1.0 g was applied to each volunteer's leg (from knee to ankle). In the laboratory, the gel dosage form contained 20% clove oil (Gel B) or 10% clove plus 10% makaen oil mixture (Gel E) were promising plant-based repellents against three mosquito species and gave significantly longer complete protection times of 4-5 hours than all other developing products. Therefore, their efficacy in the field was evaluated. Under field conditions, Gel E showed complete protection for 4 hours and gave 95.7% repellency after 5 hours application, whereas Gel B and 20% deet (di-methyl benzamide) provided only 86.8 and 82.7% repellency after treatment, respectively against Ae. aegypti, daytime-biting mosquitos. For nighttime-biting, the 3 repellents under development yielded equally excellent (average 97.1%) repellency for 5 hours against the predominant Cx. quinquefasciatus and Mansonia uniformis, but they gave 89.0% repellency against Cx. tritaeniorhynchus and Cx. gelidus. This finding demonstrated the effectiveness of Gel B and Gel E products for possible use by low-income rural communities against various mosquito species. PMID:15691131

  8. Physical features and chitin content of eggs from the mosquito vectors Aedes aegypti, Anopheles aquasalis and Culex quinquefasciatus: Connection with distinct levels of resistance to desiccation.

    PubMed

    Farnesi, Luana Cristina; Menna-Barreto, Rubem Figueiredo Sadok; Martins, Ademir Jesus; Valle, Denise; Rezende, Gustavo Lazzaro

    2015-12-01

    Mosquito eggs are laid in water but freshly laid eggs are susceptible to dehydration, if their surroundings dry out at the first hours of development. During embryogenesis of different mosquito vectors the serosal cuticle, an extracellular matrix, is produced; it wraps the whole embryo and becomes part of the eggshell. This cuticle is an essential component of the egg resistance to desiccation (ERD). However, ERD is variable among species, sustaining egg viability for different periods of time. While Aedes aegypti eggs can survive for months in a dry environment (high ERD), those of Anopheles aquasalis and Culex quinquefasciatus in the same condition last, respectively, for one day (medium ERD) or a few hours (low ERD). Resistance to desiccation is determined by the rate of water loss, dehydration tolerance and total amount of water of a given organism. The ERD variability observed among mosquitoes probably derives from diverse traits. We quantified several attributes of whole eggs, potentially correlated with the rate of water loss: length, width, area, volume, area/volume ratio and weight. In addition, some eggshell aspects were also evaluated, such as absolute and relative weight, weight/area relationship (herein called surface density) and chitin content. Presence of chitin specifically in the serosal cuticle as well as aspects of endochorion external surface were also investigated. Three features could be related to differences on ERD levels: chitin content, directly related to ERD, the increase in the egg volume during embryogenesis and the eggshell surface density, which were both inversely related to ERD. Although data suggest that the amount of chitin in the eggshell is relevant for egg impermeability, the participation of other yet unidentified eggshell attributes must be considered in order to account for the differences in the ERD levels observed among Ae. aegypti, An. aquasalis and Cx. quinquefasciatus. PMID:26514070

  9. Next-Generation Site-Directed Transgenesis in the Malaria Vector Mosquito Anopheles gambiae: Self-Docking Strains Expressing Germline-Specific phiC31 Integrase

    PubMed Central

    Meredith, Janet M.; Underhill, Ann; McArthur, Clare C.; Eggleston, Paul

    2013-01-01

    Diseases transmitted by mosquitoes have a devastating impact on global health and the situation is complicated due to difficulties with both existing control measures and the impact of climate change. Genetically modified mosquitoes that are refractory to disease transmission are seen as having great potential in the delivery of novel control strategies. The Streptomyces phage phiC31 integrase system has been successfully adapted for site-directed transgene integration in a range of insects, thus overcoming many limitations due to size constraints and random integration associated with transposon-mediated transformation. Using this technology, we previously published the first site-directed transformation of Anopheles gambiae, the principal vector of human malaria. Mosquitoes were initially engineered to incorporate the phiC31 docking site at a defined genomic location. A second phase of genetic modification then achieved site-directed integration of an anti-malarial effector gene. In the current publication we report improved efficiency and utility of the phiC31 integrase system following the generation of Anopheles gambiae self-docking strains. Four independent strains, with docking sites at known locations on three different chromosome arms, were engineered to express integrase under control of the regulatory regions of the nanos gene from Anopheles gambiae. The resulting protein accumulates in the posterior oocyte to provide integrase activity at the site of germline development. Two self-docking strains, exhibiting significantly different levels of integrase expression, were assessed for site-directed transgene integration and found to demonstrate greatly improved survival and efficiency of transformation. In the fight against malaria, it is imperative to establish a broad repertoire of both anti-malarial effector genes and tissue-specific promoters to regulate their expression, enabling those offering maximum effect with minimum fitness cost to be identified

  10. Prevalence and distribution of pox-like lesions, avian malaria, and mosquito vectors in Kipahulu valley, Haleakala National Park, Hawai'i, USA

    USGS Publications Warehouse

    Aruch, Samuel; Atkinson, Carter T.; Savage, Amy F.; LaPointe, Dennis

    2007-01-01

    We determined prevalence and altitudinal distribution of introduced avian malarial infections (Plasmodium relictum) and pox-like lesions (Avipoxvirus) in forest birds from Kīpahulu Valley, Haleakalā National Park, on the island of Maui, and we identified primary larval habitat for the mosquito vector of this disease. This intensively managed wilderness area and scientific reserve is one of the most pristine areas of native forest remaining in the state of Hawai‘i, and it will become increasingly important as a site for restoration and recovery of endangered forest birds. Overall prevalence of malarial infections in the valley was 8% (11/133) in native species and 4% (4/101) in nonnative passerines; prevalence was lower than reported for comparable elevations and habitats elsewhere in the state. Infections occurred primarily in ‘Apapane (Himatione sanguinea) and Hawai‘i ‘Amakihi (Hemignathus virens) at elevations below 1,400 m. Pox-like lesions were detected in only two Hawai‘i ‘Amakihi (2%; 2/94) at elevations below 950 m. We did not detect malaria or pox in birds caught at 1,400 m in upper reaches of the valley. Adult mosquitoes (Culex quinquefasciatus) were captured at four sites at elevations of 640, 760, 915, and 975 m, respectively. Culex quinquefasciatus larvae were found only in rock holes along intermittent tributaries of the two largest streams in the valley, but not in standing surface water, pig wallows, ground pools, tree cavities, and tree fern cavities. Mosquito populations in the valley are low, and they are probably influenced by periods of high rainfall that flush stream systems.

  11. Blood meal analysis, flavivirus screening, and influence of meteorological variables on the dynamics of potential mosquito vectors of West Nile virus in northern Italy.

    PubMed

    Roiz, David; Vazquez, Ana; Rosà, Roberto; Muñoz, Joaquin; Arnoldi, Daniele; Rosso, Fausta; Figuerola, Jordi; Tenorio, Antonio; Rizzoli, Annapaola

    2012-06-01

    An extended area of northern Italy has experienced several West Nile virus (WNV) outbreaks and the emergence of Usutu virus (USUV) during previous years. Our aim was to study some of the factors that could explain disease patterns in the Trentino region, where circulation was detected in human sera and sentinel chickens, but no human or equine cases were reported. We collected Culex species (Diptera: Culicidae) in peridomestic environments. The collected specimens were analyzed for feeding behavior, the influence of temperature and rainfall on the abundance of mosquitoes, and the occurrence of flaviviruses. Analysis of blood meals showed that Culex pipiens fed mainly on blackbirds (Turdus merula) and house sparrows (Passer domesticus), while Culex hortensis fed strictly on lizards. The abundance of Cx. pipiens females correlated positively with mean temperature and negatively with rainfall (one to four weeks before capture). This negative relationship could be due to the direct effect of the flushing of habitats together with an indirect effect of oviposition repellency. The mean weekly temperature influenced the abundance of Cx. hortensis. No flaviviruses were detected in the analyzed Culex mosquitoes. These data suggest a silent cycle at low enzootic transmission levels in the area. Furthermore, we present the first contribution to understanding the transmission role of Cx. pipiens mosquitoes in Italy by identifying vertebrate hosts to species level. PMID:22548533

  12. Mosquito surveillance for prevention and control of emerging mosquito-borne diseases in Portugal - 2008-2014.

    PubMed

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

    2014-11-01

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

  13. Evaluation of attractive toxic sugar bait (ATSB)-barrier for control of vector and nuisance mosquitoes and its effect on non-target organisms in sub-tropical environments in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated the efficacy of attractive toxic sugar baits (ATSB) in the laboratory and the field with the Environmental Protection Agency exempt active ingredient eugenol against vector and nuisance mosquitoes. In the laboratory, eugenol combined in attractive sugar bait (ASB) solution provided high...

  14. Contrasting genetic structure between mitochondrial and nuclear markers in the dengue fever mosquito from Rio de Janeiro: implications for vector control

    PubMed Central

    Rašić, Gordana; Schama, Renata; Powell, Rosanna; Maciel-de Freitas, Rafael; Endersby-Harshman, Nancy M; Filipović, Igor; Sylvestre, Gabriel; Máspero, Renato C; Hoffmann, Ary A

    2015-01-01

    Dengue is the most prevalent global arboviral disease that affects over 300 million people every year. Brazil has the highest number of dengue cases in the world, with the most severe epidemics in the city of Rio de Janeiro (Rio). The effective control of dengue is critically dependent on the knowledge of population genetic structuring in the primary dengue vector, the mosquito Aedes aegypti. We analyzed mitochondrial and nuclear genomewide single nucleotide polymorphism markers generated via Restriction-site Associated DNA sequencing, as well as traditional microsatellite markers in Ae. aegypti from Rio. We found four divergent mitochondrial lineages and a strong spatial structuring of mitochondrial variation, in contrast to the overall nuclear homogeneity across Rio. Despite a low overall differentiation in the nuclear genome, we detected strong spatial structure for variation in over 20 genes that have a significantly altered expression in response to insecticides, xenobiotics, and pathogens, including the novel biocontrol agent Wolbachia. Our results indicate that high genetic diversity, spatially unconstrained admixing likely mediated by male dispersal, along with locally heterogeneous genetic variation that could affect insecticide resistance and mosquito vectorial capacity, set limits to the effectiveness of measures to control dengue fever in Rio. PMID:26495042

  15. Synergistic action of octopamine receptor agonists on the activity of selected novel insecticides for control of dengue vector Aedes aegypti (Diptera: Culicidae) mosquito.

    PubMed

    Ahmed, Mohamed Ahmed Ibrahim; Vogel, Christoph Franz Adam

    2015-05-01

    Studying insecticide resistance in mosquitoes has attracted the attention of many scientists to elucidate the pathways of resistance development and to design novel strategies in order to prevent or minimize the spread and evolution of resistance. Here, we tested the synergistic action of piperonyl butoxide (PBO) and two octopamine receptor (OR) agonists, amitraz (AMZ) and chlordimeform (CDM) on selected novel insecticides to increase their lethal action on the fourth instar larvae of Aedes aegypti L. However, chlorfenapyr was the most toxic insecticide (LC50 = 193, 102, and 48 ng/ml, after 24, 48, and 72 h exposure, respectively) tested. Further, PBO synergized all insecticides and the most toxic combinatorial insecticide was nitenpyram even after 48 and 72 h exposure. In addition, OR agonists significantly synergized most of the selected insecticides especially after 48 and 72 h exposure. The results imply that the synergistic effects of amitraz are a promising approach in increasing the potency of certain insecticides in controlling the dengue vector Ae. aegypti mosquito. PMID:25987220

  16. [The mosquito-borne viruses in Europe].

    PubMed

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

    2015-03-01

    Epidemiologic changes of vector-borne diseases in recent years have multiple causes, including climate change. There are about 3500 species of mosquitoes worldwide, three-quarters of which live in tropical and subtropical wetlands. Main viruses transmitted by mosquitoes in Europe belong to the genus Flavivirus; some of them have been recently reported in Italy (Usutu and Japanese encephalitis virus), while others have been circulating for years and autochthonous transmission has been documented (West Nile virus). Mosquito-borne viruses can be classified according to the vector (Aedes or Culex), which, in turn, is associated with different vertebrate host and pathology. The Flavivirus transmitted by Culex have birds as a reservoir and can cause meningoencephalitis, while viruses transmitted by Aedes have primates as reservoir, do not have neurotropism and mainly cause hemorrhagic diseases. Other arbovirus, potentially responsible of epidemics, are the Chikungunya virus (Alphavirus family), introduced for the first time in Europe in 2007, and the virus of Rift Valley fever (Phlebovirus family). The spread in non-endemic areas of vector-born diseases have highlighted the importance of surveillance systems and vector control strategies. PMID:25805223

  17. Using a new odour-baited device to explore options for luring and killing outdoor-biting malaria vectors: a report on design and field evaluation of the Mosquito Landing Box

    PubMed Central

    2013-01-01

    Background Mosquitoes that bite people outdoors can sustain malaria transmission even where effective indoor interventions such as bednets or indoor residual spraying are already widely used. Outdoor tools may therefore complement current indoor measures and improve control. We developed and evaluated a prototype mosquito control device, the ‘Mosquito Landing Box’ (MLB), which is baited with human odours and treated with mosquitocidal agents. The findings are used to explore technical options and challenges relevant to luring and killing outdoor-biting malaria vectors in endemic settings. Methods Field experiments were conducted in Tanzania to assess if wild host-seeking mosquitoes 1) visited the MLBs, 2) stayed long or left shortly after arrival at the device, 3) visited the devices at times when humans were also outdoors, and 4) could be killed by contaminants applied on the devices. Odours suctioned from volunteer-occupied tents were also evaluated as a potential low-cost bait, by comparing baited and unbaited MLBs. Results There were significantly more Anopheles arabiensis, An. funestus, Culex and Mansonia mosquitoes visiting baited MLB than unbaited controls (P≤0.028). Increasing sampling frequency from every 120 min to 60 and 30 min led to an increase in vector catches of up to 3.6 fold (P≤0.002), indicating that many mosquitoes visited the device but left shortly afterwards. Outdoor host-seeking activity of malaria vectors peaked between 7:30 and 10:30pm, and between 4:30 and 6:00am, matching durations when locals were also outdoors. Maximum mortality of mosquitoes visiting MLBs sprayed or painted with formulations of candidate mosquitocidal agent (pirimiphos-methyl) was 51%. Odours from volunteer occupied tents attracted significantly more mosquitoes to MLBs than controls (P<0.001). Conclusion While odour-baited devices such as the MLBs clearly have potential against outdoor-biting mosquitoes in communities where LLINs are used, candidate

  18. Inducible immune factors of the vector mosquito Anopheles gambiae: biochemical purification of a defensin antibacterial peptide and molecular cloning of preprodefensin cDNA.

    PubMed

    Richman, A M; Bulet, P; Hetru, C; Barillas-Mury, C; Hoffmann, J A; Kafalos, F C

    1996-08-01

    Larvae of the mosquito vector of human malaria, Anopheles gambiae, were inoculated with bacteria and extracts were biochemically fractionated by reverse-phase HPLC. Multiple induced polypeptides and antibacterial activities were observed following bacterial infection, including a member of the insect defensin family of antibacterial proteins. A cDNA encoding An. gambiae preprodefensin was isolated using PCR primers based on phylogenetically conserved sequences. The mature peptide is highly conserved, but the signal and propeptide segments are not, relative to corresponding defensin sequences of other insects. Defensin expression is induced in response to bacterial infection, in both adult and larval stages. In contrast, pupae express defensin mRNA constitutively. Defensin expression may prove a valuable molecular marker to monitor the An. gambiae host response to infection by parasitic protozoa of medical importance. PMID:8799739

  19. Relative abundance of tree hole-breeding mosquitoes in Boone County, Missouri, USA, with emphasis on the vector potential of Aedes triseriatus for canine heartworm, Dirofilaria immitis (Spirurida: Filariidae).

    PubMed

    Debboun, Mustapha; Green, Theodore J; Rueda, Leopoldo M; Hall, Robert D

    2005-09-01

    Aedes (Protomacleaya) triseriatus currently shares its habitat in the USA with the introduced species Aedes (Finlaya) japonicus and Aedes (Stegomyia) albopictus. In the late 1980s, before the introduction of these 2 species, Ae. triseriatus was the dominant tree hole- and artificial container-breeding mosquito in central Missouri. Aedes triseriatus represented 89% of the mosquito immatures collected from water-filled tree holes and artificial containers at 3 forested field sites in central Missouri, from May to October, 1986 to 1988. Laboratory-reared female Ae. triseriatus were able to support larval development of Dirofilaria immitis (canine heartworm) to the infective 3rd larval stage. A blood meal from a microfilaremic Collie-mix dog was sufficient to infect adult female mosquitoes, indicating that Ae. triseriatus is a possible vector of canine heartworm in central Missouri. Confirmation of the vector status of this species depends on the yet-to-be observed transmission of D. immitis by Ae. triseriatus in the field, possibly by experimental infection of dogs by wild-caught mosquitoes. Defining the role of this species in epizootic outbreaks could contribute toward accurate risk assessment as the abundance of Ae. triseriatus increases and decreases in response to the success of Ae. albopictus, Ae. japonicus, or other introduced container-breeding mosquitoes. PMID:16252517

  20. trans-Packaged West Nile virus-like particles: infectious properties in vitro and in infected mosquito vectors.

    PubMed

    Scholle, Frank; Girard, Yvette A; Zhao, Qizu; Higgs, Stephen; Mason, Peter W

    2004-11-01

    A trans-packaging system for West Nile virus (WNV) subgenomic replicon RNAs (repRNAs), deleted for the structural coding region, was developed. WNV repRNAs were efficiently encapsidated by the WNV C/prM/E structural proteins expressed in trans from replication-competent, noncytopathic Sindbis virus-derived RNAs. Infectious virus-like particles (VLPs) were produced in titers of up to 10(9) infectious units/ml. WNV VLPs established a single round of infection in a variety of different cell lines without production of progeny virions. The infectious properties of WNV and VLPs were indistinguishable when efficiencies of infection of a number of different cell lines and inhibition of infection by neutralizing antibodies were determined. To investigate the usefulness of VLPs to address biological questions in vivo, Culex pipiens quinquefasciatus mosquitoes were orally and parenterally infected with VLPs, and dissected tissues were analyzed for WNV antigen expression. Antigen-positive cells in midguts of orally infected mosquitoes were detected as early as 2 days postinfection and as late as 8 days. Intrathoracic inoculation of VLPs into mosquitoes demonstrated a dose-dependent pattern of infection of secondary tissues and identified fat body, salivary glands, tracheal cells, and midgut muscle as susceptible WNV VLP infection targets. These results demonstrate that VLPs can serve as a valuable tool for the investigation of tissue tropism during the early stages of infection, where virus spread and the need for biosafety level 3 containment complicate the use of wild-type virus. PMID:15479801

  1. Competitive Reduction by Satyrization? Evidence for Interspecific Mating in Nature and Asymmetric Reproductive Competition between Invasive Mosquito Vectors

    PubMed Central

    Tripet, Frederic; Lounibos, L. Philip; Robbins, Dannielle; Moran, Jenny; Nishimura, Naoya; Blosser, Erik M.

    2011-01-01

    Upon mating, male mosquitoes transfer accessory gland proteins (Acps) that induce refractoriness to further mating in females. This can also occur because of cross-insemination by males of related species, a process known as mating interference (satyrization). This mechanism could explain the competitive displacement of resident Aedes aegypti by the invasive Aedes albopictus where they co-occur. We tested this hypothesis in mosquito populations in Florida. A new polymerase chain reaction species diagnostic applied to sperm dissected from 304 field-collected females revealed bidirectional cross-mating in five (1.6%) individuals. Cross-injections of females with Acps showed that Ae. albopictus males induced monogamy in heterospecific females but not Ae. aegypti males. Despite its low frequency in the areas under study, the first evidence of cross-mating in nature and the asymmetric effect of Acps on mating suggest that satyrization may have initially contributed to the observed competitive reduction of Ae. aegypti by invasive Ae. albopictus in many areas. PMID:21813845

  2. A review of recent knowledge of the ecology of the main vectors of trypanosomiasis*

    PubMed Central

    Langridge, W. P.; Kernaghan, R. J.; Glover, P. E.

    1963-01-01

    In this survey of recent ecological research on the main vectors of trypanosomiasis in those countries of East, Central and West Africa that are not predominantly French-speaking, the authors, after outlining the distribution of tsetse flies and the type of country in which they occur, discuss the direct and indirect effects of climate on these insects—particularly on their physiological water balance and on pupal fat reserves—and their recent advances into new areas. They review the considerable work that has been done on the resting habits and breeding-sites of different Glossina species, knowledge of which is important for effective control, and research on predators of pupae and adult flies and on the feeding activity of tsetse flies. Means of assessing populations and various factors affecting the size and nutritional status of tsetse flies are also discussed, as is the effect on the fly population of artificial changes in the habitat. Finally, a plea is made for a revision of present methods of land use and stock management, if full advantage is to be taken of achievements in fly control. PMID:13928678

  3. Rapid detection and identification of Wuchereria bancrofti, Brugia malayi, B. pahangi, and Dirofilaria immitis in mosquito vectors and blood samples by high resolution melting real-time PCR.

    PubMed

    Thanchomnang, Tongjit; Intapan, Pewpan M; Tantrawatpan, Chairat; Lulitanond, Viraphong; Chungpivat, Sudchit; Taweethavonsawat, Piyanan; Kaewkong, Worasak; Sanpool, Oranuch; Janwan, Penchom; Choochote, Wej; Maleewong, Wanchai

    2013-12-01

    A simple, rapid, and high-throughput method for detection and identification of Wuchereria bancrofti, Brugia malayi, Brugia pahangi, and Dirofilaria immitis in mosquito vectors and blood samples was developed using a real-time PCR combined with high-resolution melting (HRM) analysis. Amplicons of the 4 filarial species were generated from 5S rRNA and spliced leader sequences by the real-time PCR and their melting temperatures were determined by the HRM method. Melting of amplicons from W. bancrofti, B. malayi, D. immitis, and B. pahangi peaked at 81.5±0.2℃, 79.0±0.3℃, 76.8±0.1℃, and 79.9±0.1℃, respectively. This assay is relatively cheap since it does not require synthesis of hybridization probes. Its sensitivity and specificity were 100%. It is a rapid and technically simple approach, and an important tool for population surveys as well as molecular xenomonitoring of parasites in vectors. PMID:24516268

  4. Rapid Detection and Identification of Wuchereria bancrofti, Brugia malayi, B. pahangi, and Dirofilaria immitis in Mosquito Vectors and Blood Samples by High Resolution Melting Real-Time PCR

    PubMed Central

    Thanchomnang, Tongjit; Intapan, Pewpan M.; Tantrawatpan, Chairat; Lulitanond, Viraphong; Chungpivat, Sudchit; Taweethavonsawat, Piyanan; Kaewkong, Worasak; Sanpool, Oranuch; Janwan, Penchom; Choochote, Wej

    2013-01-01

    A simple, rapid, and high-throughput method for detection and identification of Wuchereria bancrofti, Brugia malayi, Brugia pahangi, and Dirofilaria immitis in mosquito vectors and blood samples was developed using a real-time PCR combined with high-resolution melting (HRM) analysis. Amplicons of the 4 filarial species were generated from 5S rRNA and spliced leader sequences by the real-time PCR and their melting temperatures were determined by the HRM method. Melting of amplicons from W. bancrofti, B. malayi, D. immitis, and B. pahangi peaked at 81.5±0.2℃, 79.0±0.3℃, 76.8±0.1℃, and 79.9±0.1℃, respectively. This assay is relatively cheap since it does not require synthesis of hybridization probes. Its sensitivity and specificity were 100%. It is a rapid and technically simple approach, and an important tool for population surveys as well as molecular xenomonitoring of parasites in vectors. PMID:24516268

  5. Measurement of landing mosquito density on humans

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  6. Hidden Sylvatic Foci of the Main Vector of Chagas Disease Triatoma infestans: Threats to the Vector Elimination Campaign?

    PubMed Central

    Schachter-Broide, Judith; Dujardin, Jean-Pierre; Dotson, Ellen M.; Kitron, Uriel; Gürtler, Ricardo E.

    2011-01-01

    Background Establishing the sources of reinfestation after residual insecticide spraying is crucial for vector elimination programs. Triatoma infestans, traditionally considered to be limited to domestic or peridomestic (abbreviated as D/PD) habitats throughout most of its range, is the target of an elimination program that has achieved limited success in the Gran Chaco region in South America. Methodology/Principal Findings During a two-year period we conducted semi-annual searches for triatomine bugs in every D/PD site and surrounding sylvatic habitats after full-coverage spraying of pyrethroid insecticides of all houses in a well-defined rural area in northwestern Argentina. We found six low-density sylvatic foci with 24 T. infestans in fallen or standing trees located 110–2,300 m from the nearest house or infested D/PD site detected after insecticide spraying, when house infestations were rare. Analysis of two mitochondrial gene fragments of 20 sylvatic specimens confirmed their species identity as T. infestans and showed that their composite haplotypes were the same as or closely related to D/PD haplotypes. Population studies with 10 polymorphic microsatellite loci and wing geometric morphometry consistently indicated the occurrence of unrestricted gene flow between local D/PD and sylvatic populations. Mitochondrial DNA and microsatellite sibship analyses in the most abundant sylvatic colony revealed descendents from five different females. Spatial analysis showed a significant association between two sylvatic foci and the nearest D/PD bug population found before insecticide spraying. Conclusions Our study shows that, despite of its high degree of domesticity, T. infestans has sylvatic colonies with normal chromatic characters (not melanic morphs) highly connected to D/PD conspecifics in the Argentinean Chaco. Sylvatic habitats may provide a transient or permanent refuge after control interventions, and function as sources for D/PD reinfestation. The

  7. Novel tests for rapid detection of insecticide resistance in mosquito vectors. Final report, 15 June 1985-31 January 1989

    SciTech Connect

    Georghiou, G.P.

    1989-01-31

    This project is concerned with the formulation of novel diagnostic tests for the detection of organophosphate (OP) resistance in individual mosquitoes. Emphasis was placed on the mechanisms of detoxification by esterases and of insensitive acetycholinesterase. Seven diagnostic tests have resulted from this research to date. Five concern esterases, and two insensitive acetylcholinesterase. An eighth procedure concerns the qualification of proteins in single insects and is used in conjunction with other tests to account for variations in the size of the test insect. Three of the tests developed for esterases (FP/Est, NC/Est and MT/Est) utilize the ability of these enzymes to hydrolyze naphthyl acetate, and two (Dot-Blot/Est and ELISA/Est) involve immunological reactions. The tests for insensitive acetylcholinesterase (NC/AChE and MT/AChE) utilize the differences in inhibitory properties of insecticides on insensitive and normal enzymes.

  8. Bifenthrin: a useful pyrethroid insecticide for treatment of mosquito nets.

    PubMed

    Hougard, J M; Zaim, S Duchony M; Guillet, P

    2002-05-01

    Bifenthrin, a pyrethroid insecticide already used in agriculture was evaluated in laboratory conditions against susceptible and pyrethroid resistant mosquitoes, as a potential insecticide for treatment of mosquito nets. Two laboratory strains of Anopheles gambiae s.s. Giles, the major malaria vector in Africa, and two of Culex quinquefasciatus Say, a major pest mosquito in urban areas, were used. Compared with other pyrethroids such as permethrin and deltamethrin, the intrinsic toxicity of bifenthrin, measured by topical application with susceptible strains, was intermediate. By forced tarsal contact on filter papers (cylinder tests) or on netting materials (cone tests), bifenthrin was found slightly more effective against A. gambiae than against C. quinquefasciatus, in terms of mortality and knock-down effect. With free flying mosquitoes (tunnel tests), bifenthrin was very efficient in killing mosquitoes and inhibiting blood feeding. Against the two pyrethroid resistant strains, bifenthrin was relatively efficient against A. gambiae but the impact of resistance was greater with C. quinquefasciatus. In tunnel tests, blood feeding remained almost entirely inhibited with the two species despite resistance. The high mortality of susceptible mosquitoes and excellent blood feeding inhibition of susceptible and resistant strains makes bifenthrin a good candidate for treatment of netting materials, particularly in areas where C. quinquefasciatus, the main nuisance in urban areas, is resistant to pyrethroids. The slower knock-down and lower irritant effect also makes this insecticide especially attractive when a mass killing effect on mosquito populations is expected. PMID:12061451

  9. Participatory mapping of target areas to enable operational larval source management to suppress malaria vector mosquitoes in Dar es Salaam, Tanzania

    PubMed Central

    Dongus, Stefan; Nyika, Dickson; Kannady, Khadija; Mtasiwa, Deo; Mshinda, Hassan; Fillinger, Ulrike; Drescher, Axel W; Tanner, Marcel; Castro, Marcia C; Killeen, Gerry F

    2007-01-01

    Background Half of the population of Africa will soon live in towns and cities where it can be protected from malaria by controlling aquatic stages of mosquitoes. Rigorous but affordable and scaleable methods for mapping and managing mosquito habitats are required to enable effective larval control in urban Africa. Methods A simple community-based mapping procedure that requires no electronic devices in the field was developed to facilitate routine larval surveillance in Dar es Salaam, Tanzania. The mapping procedure included (1) community-based development of sketch maps and (2) verification of sketch maps through technical teams using laminated aerial photographs in the field which were later digitized and analysed using Geographical Information Systems (GIS). Results Three urban wards of Dar es Salaam were comprehensively mapped, covering an area of 16.8 km2. Over thirty percent of this area were not included in preliminary community-based sketch mapping, mostly because they were areas that do not appear on local government residential lists. The use of aerial photographs and basic GIS allowed rapid identification and inclusion of these key areas, as well as more equal distribution of the workload of malaria control field staff. Conclusion The procedure developed enables complete coverage of targeted areas with larval control through comprehensive spatial coverage with community-derived sketch maps. The procedure is practical, affordable, and requires minimal technical skills. This approach can be readily integrated into malaria vector control programmes, scaled up to towns and cities all over Tanzania and adapted to urban settings elsewhere in Africa. PMID:17784963

  10. Larvicidal potential of wild mustard (Cleome viscosa) and gokhru (Tribulus terrestris) against mosquito vectors in the semi-arid region of Western Rajasthan.

    PubMed

    Bansal, S K; Singh, Karam V; Sharma, Sapna

    2014-03-01

    Cleome viscosa L. (Family: Capparaceae) commonly known as Tickweed or wild mustard and Tribulus terrestris L. (Family: Zygophyllaceae) commonly known as Gokhru, growing wildly in the desert areas in the monsoon and post monsoon season, are of great medicinal importance. Comparative larvicidal efficacy of the extracts from seeds of C. viscosa and fruits and leaves of T. terrestris was evaluated against 3rd or early 4th stage larvae of Anopheles stephensi (Liston), Aedes aegypti (Linnaeus) and Culex quinquefasciatus (Say) in different organic solvents. 24 and 48 hr LC50 and LC90 values along with their 95% fiducial limits, regression equation, chi-square (chi2)/ heterogeneity of the response was determined by log probit regression analysis. The 24 hr LC50 values as determined for seeds of C. viscosa were 144.1, 99.5 and 127.1 (methanol); 106.3, 138.9 and 118.5 (acetone) and 166.4, 162.5 and 301.9 mg l(-1) (petroleum ether extracts) for all the three mosquito species respectively showing that methanol and acetone extracts were a little bit more effective than the petroleum ether extracts. Experiments were carried out with fruits and leaves of T. terrestris with all the solvents and mosquito species. The 24 hr LC50 values, as determined for fruits of T. terrestris were 70.8, 103.4 and 268.2 (methanol); 74.0,120.5 and 132.0 (acetone) and 73.8,113.5 and 137.4 mg l(-1) (petroleum ether extracts) while the 24 hr LC50 values for leaves were 124.3, 196.8 and 246.5 (methanol); 163.4, 196.9 and 224.3 (acetone) and 135.8, 176.8 and 185.9 mg l(-1) (petroleum ether extracts) for all the three mosquito species respectively. The results clearly indicate that fruit extracts of T. terrestris were more effective as compared to leaves extracts in the three solvents tested. Larvae of An. stephensi were found more sensitive to both fruit and leaves extracts of T. terrestris followed by larvae of Ae. aegypti and Cx. quinquefasciatus. Extracts from the seeds of C. viscosa were found less

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

    PubMed Central

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

    2014-01-01

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

  12. The value of long-term mosquito surveillance data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One of the most important activities performed by mosquito and vector control agencies is mosquito population surveillance. Mosquito population surveillance data are the written results of adult or larval mosquito sampling, recorded and preserved on paper forms or entered into electronic spreadshee...

  13. Sensory interactions between six common aroma vectors explain four main red wine aroma nuances.

    PubMed

    Ferreira, Vicente; Sáenz-Navajas, María-Pilar; Campo, Eva; Herrero, Paula; de la Fuente, Arancha; Fernández-Zurbano, Purificación

    2016-05-15

    This work aims at assessing the aromatic sensory dimensions linked to 6 common wine aroma vectors (N, norisoprenoids; A, branched acids; F, enolones; E, branched ethyl esters; L, fusel alcohols, M, wood compounds) varying in their natural range of occurrence. Wine models were built by adding the vectors at two levels (fractional factorial design 2(VI)) to a de-aromatised aged red wine. Twenty other different models were evaluated by descriptive analysis. Red, black and dried fruits and woody notes were satisfactorily reproduced. Individual vectors explained just 15% of the sensory space, mostly dependent on perceptual interactions. N influences dried and black fruits and suppresses red fruits. A suppresses black fruits and enhances red and dried fruits. F exerts a major role on red fruits. E suppresses dried fruits and modulates black fruits. L is revealed as a strong suppressor of red fruits and particularly of woody notes. PMID:26775994

  14. Mosquito breeding site water temperature observations and simulations towards improved vector-borne disease models for Africa.

    PubMed

    Asare, Ernest O; Tompkins, Adrian M; Amekudzi, Leonard K; Ermert, Volker; Redl, Robert

    2016-01-01

    An energy budget model is developed to predict water temperature of typical mosquito larval developmental habitats. It assumes a homogeneous mixed water column driven by empirically derived fluxes. The model shows good agreement at both hourly and daily time scales with 10-min temporal resolution observed water temperatures, monitored between June and November 2013 within a peri-urban area of Kumasi, Ghana. There was a close match between larvae development times calculated using either the model-derived or observed water temperatures. The water temperature scheme represents a significant improvement over assuming the water temperature to be equal to air temperature. The energy budget model requires observed minimum and maximum temperatures, information that is generally available from weather stations. Our results show that hourly variations in water temperature are important for the simulation of aquatic-stage development times. By contrast, we found that larval development is insensitive to sub-hourly variations. Modelling suggests that in addition to water temperature, accurate estimation of degree-day development time is very important to correctly predict the larvae development times. The results highlight the potential of the model to predict water temperature of temporary bodies of surface water. Our study represents an important contribution towards the improvement of weatherdriven dynamical disease models, including those designed for malaria early forecasting systems. PMID:27063735

  15. Spatio-temporal Modeling of Mosquito Distribution

    NASA Astrophysics Data System (ADS)

    Dumont, Y.; Dufourd, C.

    2011-11-01

    We consider a quasilinear parabolic system to model mosquito displacement. In order to use efficiently vector control tools, like insecticides, and mechanical control, it is necessary to provide density estimates of mosquito populations, taking into account the environment and entomological knowledges. After a brief introduction to mosquito dispersal modeling, we present some theoretical results. Then, considering a compartmental approach, we get a quasilinear system of PDEs. Using the time splitting approach and appropriate numerical methods for each operator, we construct a reliable numerical scheme. Considering vector control scenarii, we show that the environment can have a strong influence on mosquito distribution and in the efficiency of vector control tools.

  16. Adaptation and evaluation of the bottle assay for monitoring insecticide resistance in disease vector mosquitoes in the Peruvian Amazon

    PubMed Central

    Zamora Perea, Elvira; Balta León, Rosario; Palomino Salcedo, Miriam; Brogdon, William G; Devine, Gregor J

    2009-01-01

    Background The purpose of this study was to establish whether the "bottle assay", a tool for monitoring insecticide resistance in mosquitoes, can complement and augment the capabilities of the established WHO assay, particularly in resource-poor, logistically challenging environments. Methods Laboratory reared Aedes aegypti and field collected Anopheles darlingi and Anopheles albimanus were used to assess the suitability of locally sourced solvents and formulated insecticides for use with the bottle assay. Using these adapted protocols, the ability of the bottle assay and the WHO assay to discriminate between deltamethrin-resistant Anopheles albimanus populations was compared. The diagnostic dose of deltamethrin that would identify resistance in currently susceptible populations of An. darlingi and Ae. aegypti was defined. The robustness of the bottle assay during a surveillance exercise in the Amazon was assessed. Results The bottle assay (using technical or formulated material) and the WHO assay were equally able to differentiate deltamethrin-resistant and susceptible An. albimanus populations. A diagnostic dose of 10 μg a.i./bottle was identified as the most sensitive discriminating dose for characterizing resistance in An. darlingi and Ae. aegypti. Treated bottles, prepared using locally sourced solvents and insecticide formulations, can be stored for > 14 days and used three times. Bottles can be stored and transported under local conditions and field-assays can be completed in a single evening. Conclusion The flexible and portable nature of the bottle assay and the ready availability of its components make it a potentially robust and useful tool for monitoring insecticide resistance and efficacy in remote areas that require minimal cost tools. PMID:19728871

  17. SAS6-like protein in Plasmodium indicates that conoid-associated apical complex proteins persist in invasive stages within the mosquito vector

    PubMed Central

    Wall, Richard J.; Roques, Magali; Katris, Nicholas J.; Koreny, Ludek; Stanway, Rebecca R.; Brady, Declan; Waller, Ross F.; Tewari, Rita

    2016-01-01

    The SAS6-like (SAS6L) protein, a truncated paralogue of the ubiquitous basal body/centriole protein SAS6, has been characterised recently as a flagellum protein in trypanosomatids, but associated with the conoid in apicomplexan Toxoplasma. The conoid has been suggested to derive from flagella parts, but is thought to have been lost from some apicomplexans including the malaria-causing genus Plasmodium. Presence of SAS6L in Plasmodium, therefore, suggested a possible role in flagella assembly in male gametes, the only flagellated stage. Here, we have studied the expression and role of SAS6L throughout the Plasmodium life cycle using the rodent malaria model P. berghei. Contrary to a hypothesised role in flagella, SAS6L was absent during gamete flagellum formation. Instead, SAS6L was restricted to the apical complex in ookinetes and sporozoites, the extracellular invasive stages that develop within the mosquito vector. In these stages SAS6L forms an apical ring, as we show is also the case in Toxoplasma tachyzoites. The SAS6L ring was not apparent in blood-stage invasive merozoites, indicating that the apical complex is differentiated between the different invasive forms. Overall this study indicates that a conoid-associated apical complex protein and ring structure is persistent in Plasmodium in a stage-specific manner. PMID:27339728

  18. Bromeliad-inhabiting mosquitoes in an urban botanical garden of dengue endemic Rio de Janeiro. Are bromeliads productive habitats for the invasive vectors Aedes aegypti and Aedes albopictus?

    PubMed Central

    Mocellin, Márcio Goulart; Simões, Taynãna César; do Nascimento, Teresa Fernandes Silva; Teixeira, Maria Lucia França; Lounibos, Leon Philip; de Oliveira, Ricardo Lourenço

    2012-01-01

    Immatures of both Aedes aegypti and Aedes albopictus have been found in water-holding bromeliad axils in Brazil. Removal of these plants or their treatment with insecticides in public and private gardens have been undertaken during dengue outbreaks in Brazil despite uncertainty as to their importance as productive habitats for dengue vectors. From March 2005-February 2006, we sampled 120 randomly selected bromeliads belonging to 10 species in a public garden less than 200 m from houses in a dengue-endemic neighborhood in Rio de Janeiro. A total of 2,816 mosquito larvae and pupae was collected, with an average of 5.87 immatures per plant per collection. Culex (Microculex) pleuristriatus and Culex spp of the Ocellatus Group were the most abundant culicid species, found in all species of bromeliads; next in relative abundance were species of the genus Wyeomyia. Only two individuals of Ae. aegypti (0.07%) and five of Ae. albopictus (0.18%) were collected from bromeliads. By contrast, immatures of Ae. aegypti were found in manmade containers in nearly 5% of nearby houses. These results demonstrate that bromeliads are not important producers of Ae. aegypti and Ae. albopictus and, hence, should not be a focus for dengue control. However, the results of this study of only one year in a single area may not represent outcomes in other urban localities where bromeliads, Ae. aegypti and dengue coincide in more disturbed habitats. PMID:20140379

  19. Impact of larviciding with a Bacillus thuringiensis israelensis formulation, VectoBac WG, on dengue mosquito vectors in a dengue endemic site in Selangor State, Malaysia.

    PubMed

    Lee, H L; Chen, C D; Masri, S Mohd; Chiang, Y F; Chooi, K H; Benjamin, S

    2008-07-01

    The field bioefficacy of a wettable granule (WG) formulation of Bacillus thuringiensis israelensis (Bti), VectoBac WG (Bti strain AM65-52) against dengue vectors, Aedes aegypti and Ae albopictus; was evaluated in a suburban residential area (TST) and in a temporary settlement site (KB) in the state of Selangor, Malaysia. Pre-control ovitrap surveillance of the trial sites indicated a high population of both types of Aedes mosquitoes. The populations were monitored continuously by weekly ovitrapping. Bti was sprayed biweekly at a dosage of 500 g/ha by using a mist-blower. The spray application was targeted into outdoor larval habitats. If required, Bti formulation was also applied directly into indoor water-holding containers at 8 g/1,000 l. Based on ovitrap surveillance, a significant reduction in Aedes populations was evident 4 weeks after initiating the first Bti treatment. The ovitrap index (OI) and the larvae density decreased drastically in both trial sites. In TST, the indoor OI was significantly reduced from 57.50 +/- 7.50% to 19.13 +/- 5.49% (p<0.05), while the outdoor OI decreased from 38.89 +/- 11.11% to 15.36 +/- 5.93%. In KB, similarly, the OI was significantly reduced by more than half, from 66.66 +/- 6.67% to 30.26 +/- 2.99% (p< 0.05). In all cases, the reduction in OI was paralleled by reduction in larval density. PMID:19058596

  20. Environmental influences on mosquito foraging and integrated vector management can delay the evolution of behavioral resistance.

    PubMed

    Stone, Chris; Chitnis, Nakul; Gross, Kevin

    2016-03-01

    Along with the scaled-up distribution of long-lasting insecticidal nets for malaria control has become concern about insecticide resistance. A related concern regards the evolution of host-seeking periodicity from the nocturnal to the crepuscular periods of the day. Why we observe such shifts in some areas but not others and which methods could prove useful in managing such behavioral resistance remain open questions. We developed a foraging model to explore whether environmental conditions affect the evolution of behavioral resistance. We looked at the role of the abundance of blood hosts and nectar sources and investigated the potential of attractive toxic sugar baits for integrated control. Higher encounter rates with hosts and nectar sources allowed behaviorally resistant populations to persist at higher levels of bed net coverage. Whereas higher encounter rates with nectar increased the threshold where resistance emerged, higher encounter rates of hosts lowered this threshold. Adding sugar baits lowered the coverage level of bed nets required to eliminate the vector population. In certain environments, using lower bed net coverage levels together with toxic sugar baits may delay or prevent the evolution of behavioral resistance. Designing sustainable control strategies will depend on an understanding of vector behavior expressed in local environmental conditions. PMID:26989441

  1. Inhibition and Larvicidal Activity of Phenylpropanoids from Piper sarmentosum on Acetylcholinesterase against Mosquito Vectors and Their Binding Mode of Interaction

    PubMed Central

    Hematpoor, Arshia; Liew, Sook Yee; Chong, Wei Lim; Azirun, Mohd Sofian; Lee, Vannajan Sanghiran; Awang, Khalijah

    2016-01-01

    Aedes aegypti, Aedes albopictus and Culex quinquefasciatus are vectors of dengue fever and West Nile virus diseases. This study was conducted to determine the toxicity, mechanism of action and the binding interaction of three active phenylpropanoids from Piper sarmentosum (Piperaceae) toward late 3rd or early 4th larvae of above vectors. A bioassay guided-fractionation on the hexane extract from the roots of Piper sarmentosum led to the isolation and identification of three active phenylpropanoids; asaricin 1, isoasarone 2 and trans-asarone 3. The current study involved evaluation of the toxicity and acetylcholinesterase (AChE) inhibition of these compounds against Aedes aegypti, Aedes albopictus and Culex quinquefasciatus larvae. Asaricin 1 and isoasarone 2 were highly potent against Aedes aegypti, Aedes albopictus and Culex quinquefasciatus larvae causing up to 100% mortality at ≤ 15 μg/mL concentration. The ovicidal activity of asaricin 1, isoasarone 2 and trans-asarone 3 were evaluated through egg hatching. Asaricin 1 and isoasarone 2 showed potent ovicidal activity. Ovicidal activity for both compounds was up to 95% at 25μg/mL. Asaricin 1 and isoasarone 2 showed strong inhibition on acetylcholinesterase with relative IC50 values of 0.73 to 1.87 μg/mL respectively. These findings coupled with the high AChE inhibition may suggest that asaricin 1 and isoasarone 2 are neuron toxic compounds toward Aedes aegypti, Aedes albopictus and Culex quinquefasciatus. Further computational docking with Autodock Vina elaborates the possible interaction of asaricin 1 and isoasarone 2 with three possible binding sites of AChE which includes catalytic triads (CAS: S238, E367, H480), the peripheral sites (PAS: E72, W271) and anionic binding site (W83). The binding affinity of asaricin 1 and isoasarone 2 were relatively strong with asaricin 1 showed a higher binding affinity in the anionic pocket. PMID:27152416

  2. Inhibition and Larvicidal Activity of Phenylpropanoids from Piper sarmentosum on Acetylcholinesterase against Mosquito Vectors and Their Binding Mode of Interaction.

    PubMed

    Hematpoor, Arshia; Liew, Sook Yee; Chong, Wei Lim; Azirun, Mohd Sofian; Lee, Vannajan Sanghiran; Awang, Khalijah

    2016-01-01

    Aedes aegypti, Aedes albopictus and Culex quinquefasciatus are vectors of dengue fever and West Nile virus diseases. This study was conducted to determine the toxicity, mechanism of action and the binding interaction of three active phenylpropanoids from Piper sarmentosum (Piperaceae) toward late 3rd or early 4th larvae of above vectors. A bioassay guided-fractionation on the hexane extract from the roots of Piper sarmentosum led to the isolation and identification of three active phenylpropanoids; asaricin 1, isoasarone 2 and trans-asarone 3. The current study involved evaluation of the toxicity and acetylcholinesterase (AChE) inhibition of these compounds against Aedes aegypti, Aedes albopictus and Culex quinquefasciatus larvae. Asaricin 1 and isoasarone 2 were highly potent against Aedes aegypti, Aedes albopictus and Culex quinquefasciatus larvae causing up to 100% mortality at ≤ 15 μg/mL concentration. The ovicidal activity of asaricin 1, isoasarone 2 and trans-asarone 3 were evaluated through egg hatching. Asaricin 1 and isoasarone 2 showed potent ovicidal activity. Ovicidal activity for both compounds was up to 95% at 25μg/mL. Asaricin 1 and isoasarone 2 showed strong inhibition on acetylcholinesterase with relative IC50 values of 0.73 to 1.87 μg/mL respectively. These findings coupled with the high AChE inhibition may suggest that asaricin 1 and isoasarone 2 are neuron toxic compounds toward Aedes aegypti, Aedes albopictus and Culex quinquefasciatus. Further computational docking with Autodock Vina elaborates the possible interaction of asaricin 1 and isoasarone 2 with three possible binding sites of AChE which includes catalytic triads (CAS: S238, E367, H480), the peripheral sites (PAS: E72, W271) and anionic binding site (W83). The binding affinity of asaricin 1 and isoasarone 2 were relatively strong with asaricin 1 showed a higher binding affinity in the anionic pocket. PMID:27152416

  3. Anopheles sinensis mosquito insecticide resistance: comparison of three mosquito sample collection and preparation methods and mosquito age in resistance measurements

    PubMed Central

    2014-01-01

    Background Insecticide resistance monitoring in malaria mosquitoes is essential for guiding the rational use of insecticides in vector control programs. Resistance bioassay is the first step for insecticide monitoring and it lays an important foundation for molecular examination of resistance mechanisms. In the literature, various mosquito sample collection and preparation methods have been used, but how mosquito sample collection and preparation methods affect insecticide susceptibility bioassay results is largely unknown. The objectives of this study were to determine whether mosquito sample collection and preparation methods affected bioassay results, which may cause incorrect classification of mosquito resistance status. Methods The study was conducted in Anopheles sinensis mosquitoes in two study sites in central China. Three mosquito sample collection and preparation methods were compared for insecticide susceptibility, kdr frequencies and metabolic enzyme activities: 1) adult mosquitoes collected from the field; 2) F1 adults from field collected, blood-fed mosquitoes; and 3) adult mosquitoes reared from field collected larvae. Results Mosquito sample collection and preparation methods significantly affected mortality rates in the standard WHO tube resistance bioassay. Mortality rate of field-collected female adults was 10-15% higher than in mosquitoes reared from field-collected larvae and F1 adults from field collected blood-fed females. This pattern was consistent in mosquitoes from the two study sites. High kdr mutation frequency (85-95%) with L1014F allele as the predominant mutation was found in our study populations. Field-collected female adults consistently exhibited the highest monooxygenase and GST activities. The higher mortality rate observed in the field-collected female mosquitoes may have been caused by a mixture of mosquitoes of different ages, as older mosquitoes were more susceptible to deltamethrin than younger mosquitoes. Conclusions

  4. SOURCE REDUCTION BEHAVIOR AS AN INDEPENDENT MEASUREMENT OF THE IMPACT OF A PUBLIC HEALTH EDUCATION CAMPAIGN IN AN INTEGRATED VECTOR MANAGEMENT PROGRAM FOR THE ASIAN TIGER MOSQUITO

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The goal of this study was to evaluate the effectiveness of a public health educational campaign to reduce backyard mosquito-larval habitats. Three communities each, within two New Jersey counties, were randomly selected to receive (1) both education and mosquito control, (2) education only, and (3)...

  5. The main sceneries of Chagas disease transmission. The vectors, blood and oral transmissions - A comprehensive review

    PubMed Central

    Coura, José Rodrigues

    2015-01-01

    This review deals with transmission of Trypanosoma cruzi by the most important domestic vectors, blood transfusion and oral intake. Among the vectors, Triatoma infestans, Panstrongylus megistus, Rhodnius prolixus, Triatoma dimidiata, Triatoma brasiliensis, Triatoma pseudomaculata, Triatoma sordida, Triatoma maculata, Panstrongylus geniculatus, Rhodnius ecuadoriensis and Rhodnius pallescens can be highlighted. Transmission of Chagas infection, which has been brought under control in some countries in South and Central America, remains a great challenge, particularly considering that many endemic countries do not have control over blood donors. Even more concerning is the case of non-endemic countries that receive thousands of migrants from endemic areas that carry Chagas disease, such as the United States of America, in North America, Spain, in Europe, Japan, in Asia, and Australia, in Oceania. In the Brazilian Amazon Region, since Shaw et al. (1969) described the first acute cases of the disease caused by oral transmission, hundreds of acute cases of the disease due to oral transmission have been described in that region, which is today considered to be endemic for oral transmission. Several other outbreaks of acute Chagas disease by oral transmission have been described in different states of Brazil and in other South American countries. PMID:25466622

  6. Attraction of mosquitoes to domestic cats in a heartworm enzootic region.

    PubMed

    Gomes, Luciana A M; Serrão, Maria Lucia; Duarte, Rosemere; Bendas, Alexandre; Labarthe, Norma

    2007-08-01

    Heartworm disease is caused by a mosquito-borne parasite that can affect many different mammalian species and has worldwide distribution. The agent, Dirofilaria immitis (Leidy 1856), infect mainly dogs but feline infection have been frequently reported in the last decade. Feline heartworm infection is difficult to detect, therefore, low reported prevalence could reflect true low prevalence or poor diagnostic efficiency. As mosquitoes are known to be attracted differently by different mammalian species, mosquitoes were collected from both a cattery and a contiguous home located in a canine heartworm enzootic area in Niterói, state of Rio de Janeiro, Brazil. For 14 months, mosquitoes were collected weekly for genus identification, speciation when possible, and for individual blood meal identification. Culex species mosquitoes were the most captured and those most frequently found with feline blood meal, followed by Aedes species that, although captured in lower numbers, also fed on feline blood. While Culex species mosquitoes have been reported as potential secondary heartworm vectors for dogs and primary vectors for cats, the present results suggest that Aedes species mosquitoes may also be involved in feline heartworm transmission in a larger proportion than previously thought. PMID:17383920

  7. Modeling Mosquito Distribution. Impact of the Landscape

    NASA Astrophysics Data System (ADS)

    Dumont, Y.

    2011-09-01

    In order to use efficiently vector control tools, like insecticides, and mechanical control, it is necessary to provide mosquito density estimate and mosquito distribution, taking into account the environment and entomological knowledges. Mosquito dispersal modeling, together with a compartmental approach, leads to a quasilinear parabolic system. Using the time splitting approach and appropriate numerical methods for each operator, we construct a reliable numerical scheme. Considering various landscapes, we show that the environment can have a strong influence on mosquito distribution and, thus, in the efficiency or not of vector control.

  8. MOSQUITO IDENTIFICATION AND MOLECULAR XENOMONITORING OF LYMPHATIC FILARIASIS IN SELECTED ENDEMIC AREAS IN GIZA AND QUALIOUBIYA GOVERNORATES, EGYPT.

    PubMed

    Abdel-Shafi, Iman R; Shoeib, Eman Y; Attia, Samar S; Rubio, José M; Edmardash, Yusuf; El-Badry, Ayman A

    2016-04-01

    Lymphatic filariasis is a vector-borne health problem that has been focally endemic in Egypt for centuries. The chief vectors of transmission are Culicinae species. Control measures in the form of mass drug administration of DEC citrate treatment have been implemented in Nile delta for almost a decade. This study aimed to identify the prevalent mosquito species in endemic areas in Giza and Qualioubiya governorates and to monitor Wuchereria bancrofti infection by detecting the parasite DNA in collected mosquitoes. Adult mosquitoes were collected using light traps hung indoors. Microscopic examination was performed to identify and examine the morphologic characters of mosquitoes. Female Culex mosquitoes were subjected to semi-nested PCR to detect filarial DNA targeting repetitive DNA sequences (pWbl2 repetitive region) specific for W. bancrofti. The results revealed 3 species of mosquitoes Culex pipiens, Culex pusillus and Culex quinquefasciatus with the predominance of Culex pipiens (85.7%). Wuchereria bancrofti DNA was not detected in any of the collected mosquito pools. With progress of elimination programme in Nile Delta, follow up studies with larger sample size are recommended as the predominance of Culex pipiens the main lymphatic filariasis vector remains a risk of transmission in such areas. PMID:27363044

  9. Mosquito genomics: progress and challenges.

    PubMed

    Severson, David W; Behura, Susanta K

    2012-01-01

    The whole-genome sequencing of mosquitoes has facilitated our understanding of fundamental biological processes at their basic molecular levels and holds potential for application to mosquito control and prevention of mosquito-borne disease transmission. Draft genome sequences are available for Anopheles gambiae, Aedes aegypti, and Culex quinquefasciatus. Collectively, these represent the major vectors of African malaria, dengue fever and yellow fever viruses, and lymphatic filariasis, respectively. Rapid advances in genome technologies have revealed detailed information on genome architecture as well as phenotype-specific transcriptomics and proteomics. These resources allow for detailed comparative analyses within and across populations as well as species. Next-generation sequencing technologies will likely promote a proliferation of genome sequences for additional mosquito species as well as for individual insects. Here we review the current status of genome research in mosquitoes and identify potential areas for further investigations. PMID:21942845

  10. Factors influencing stakeholders attitudes toward genetically modified aedes mosquito.

    PubMed

    Amin, Latifah; Hashim, Hasrizul

    2015-06-01

    Dengue fever is a debilitating and infectious disease that could be life-threatening. It is caused by the dengue virus which affects millions of people in the tropical area. Currently, there is no cure for the disease as there is no vaccine available. Thus, prevention of the vector population using conventional methods is by far the main strategy but has been found ineffective. A genetically modified (GM) mosquito is among the favoured alternatives to curb dengue fever in Malaysia. Past studies have shown that development and diffusion of gene technology products depends heavily upon public acceptance. The purpose of this study is to identify the relevant factors influencing stakeholders' attitudes toward the GM Aedes mosquito and to analyse the relationships between all the factors using the structural equation model. A survey was carried out on 509 respondents from various stakeholder groups in the Klang Valley region of Malaysia. Results of the survey have confirmed that public perception towards complex issues such as gene technology should be seen as a multi-faceted process. The perceived benefit-perceived risk balance is very important in determining the most predominant predictor of attitudes toward a GM mosquito. In this study the stakeholders perceived the benefit of the GM mosquito as outweighing its risk, translating perceived benefit as the most important direct predictor of attitudes toward the GM mosquito. Trust in key players has a direct influence on attitudes toward the GM mosquito while moral concern exhibited an indirect influence through perceived benefits. Other factors such as attitudes toward technology and nature were also indirect predictors of attitudes toward the GM mosquito while religiosity and engagement did not exhibited any significant roles. The research findings serve as a useful database to understand public acceptance and the social construct of public attitudes towards the GM mosquito to combat dengue. PMID:24906652

  11. Host-pathogen interactions and genome evolution in two generalist and specialist microsporidian pathogens of mosquitoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The adaptation of two distantly related microsporidia to their mosquito hosts was investigated. Edhazardia aedis is a specialist pathogen that infects Aedes aegypti, the main vector of dengue and yellow fever arboviruses. Vavraia culicis is a generalist pathogen of several insects including Anophele...

  12. Contrasting patterns of tolerance between chemical and biological insecticides in mosquitoes exposed to UV-A.

    PubMed

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

    2013-09-15

    Mosquitoes are vectors of major human diseases, such as malaria, dengue or yellow fever. Because no efficient treatments or vaccines are available for most of these diseases, control measures rely mainly on reducing mosquito populations by the use of insecticides. Numerous biotic and abiotic factors are known to modulate the efficacy of insecticides used in mosquito control. Mosquito breeding sites vary from opened to high vegetation covered areas leading to a large ultraviolet gradient exposure. This ecological feature may affect the general physiology of the insect, including the resistance status against insecticides. In the context of their contrasted breeding sites, we assessed the impact of low-energetic ultraviolet exposure on mosquito sensitivity to biological and chemical insecticides. We show that several mosquito detoxification enzyme activities (cytochrome P450, glutathione S-transferases, esterases) were increased upon low-energy UV-A exposure. Additionally, five specific genes encoding detoxification enzymes (CYP6BB2, CYP6Z7, CYP6Z8, GSTD4, and GSTE2) previously shown to be involved in resistance to chemical insecticides were found over-transcribed in UV-A exposed mosquitoes, revealed by RT-qPCR experiments. More importantly, toxicological bioassays revealed that UV-exposed mosquitoes were more tolerant to four main chemical insecticide classes (DDT, imidacloprid, permethrin, temephos), whereas the bioinsecticide Bacillus thuringiensis subsp. israelensis (Bti) appeared more toxic. The present article provides the first experimental evidence of the capacity of low-energy UV-A to increase mosquito tolerance to major chemical insecticides. This is also the first time that a metabolic resistance to chemical insecticides is linked to a higher susceptibility to a bioinsecticide. These results support the use of Bti as an efficient alternative to chemical insecticides when a metabolic resistance to chemicals has been developed by mosquitoes. PMID:23911355

  13. Phylogenetic analysis of the ATP-binding cassette transporter family in three mosquito species.

    PubMed

    Lu, Hong; Xu, Yongyu; Cui, Feng

    2016-09-01

    The ATP-binding cassette (ABC) transporter family functions in the ATP-dependent transportation of various substrates across biological membranes. ABC proteins participate in various biological processes and insecticide resistance in insects, and are divided into eight subfamilies (A-H). Mosquitoes are important vectors of human diseases, but the mechanism by which the ABC transporter family evolves in mosquitoes is unknown. In this study, we classified and compared the ABC transporter families of three mosquitoes, namely, Anopheles gambiae, Aedes aegypti, and Culex pipiens quinquefasciatus. The three mosquitoes have 55, 69, and 70 ABC genes, respectively. The C. p. quinquefasciatus had approximately 40% and 65% expansion in the ABCG subfamily, mainly in ABCG1/G4, compared with the two other mosquito species. The ABCB, ABCD, ABCE, and ABCF subfamilies were conserved in the three mosquito species. The C. p. quinquefasciatus transcriptomes during development showed that the ABCG and ABCC genes were mainly highly expressed at the egg and pupal stages. The pigment-transport relative brown, white, and scarlet, as well as the ABCF subfamily, were highly expressed at the egg stage. The highly expressed genes in larvae included three ABCA3 genes. The majority of the highly expressed genes in adults were ABCG1/4 genes. These results provided insights into the evolution of the ABC transporter family in mosquitoes. PMID:27521922

  14. Understanding the effect of vector dynamics in epidemic models using center manifold analysis

    NASA Astrophysics Data System (ADS)

    Rocha, Filipe; Aguiar, Maíra; Souza, Max; Stollenwerk, Nico

    2012-09-01

    In vector borne diseases the human hosts' epidemiology often acts on a much slower time scales than the one of the mosquitos which transmit the disease as a vector from human to human, due to their vastly different life cycles. We investigate in a model with susceptible (S), infected (I) and recovered (R) humans and susceptible (U) and infected (V) mosquitoes in how far the fast time scale of the mosquito epidemiology can be slaved by the slower human epidemiology, so that for the understanding of human disease data mainly the dynamics of the human time scale is essential and only slightly perturbed by the mosquito dynamics. This analysis of the SIRUV model is qualitatively in agreement with a previously investigated simpler SISUV model, hence a feature of vector-borne diseases in general.

  15. Susceptibility of mosquitoes to ingested insecticides.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mosquitoes are important vectors of many diseases of medical and veterinary importance. Control of adult mosquitoes is conventionally through application of aerial sprays, however, there are environmental and health concerns associated with these sprays. One approach for targeted control of mosqui...

  16. Microsporidian isolates from mosquitoes of Argentina

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microsporidia are among the most common and widely distributed microbial pathogens associated with mosquitoes in nature. Since 1980 studies of microsporidia in mosquitoes of Argentina were conducted at the Laboratory of Insect Vectors of CEPAVE. Eleven morphologically unique species of microsporidia...

  17. Novel Methods for Mosquito Control using RNAi.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The discovery and development of novel insecticides for vector control is a primary focus of toxicology research conducted at the Mosquito and Fly Research Unit, Gainesville, FL. Targeting critical genes/proteins in mosquitoes using RNA interference (RNAi) is being investigated as a method to devel...

  18. [Mosquitoes (Diptera, Culicidae) and their medical importance for Portugal: challenges for the 21st century].

    PubMed

    Gouveia de Almeida, A Paulo

    2011-01-01

    Mosquitoes are dipterous insects, responsible for the transmission of several pathogenic agents to humans, causing vector-borne diseases, such as malaria, lymphatic and other filariasis, and several arboviral diseases such as yellow fever and dengue. In this revision, Culicidae or mosquitoes are summarily characterized, as well as their bioecology, internal morphology, digestive and egg maturation physiology, and the main methods for their collection and control. The epidemiology of mosquito-borne diseases depends on parameters such as Vectorial efficiency, Vector competence and Vectorial capacity, the concepts of which are presented. Forty one species of mosquitoes have been detected so far in mainland Portugal. Malaria was endemic till 1959, yellow fever outbreaks were registered in the XIX century, and human cases of dirofilarisis and West Nile fever have been detected. In face of the current climate changes in course and the threat of the (re)-introduction of exotic mosquito species, not only new cases of some of these diseases may occur, increasing their risk, but also other mosquito-borne diseases may be introduced constituting challenges for the XXI century, demanding a continued surveillance in a Public Health perspective. PMID:22713191

  19. Review: Improving our knowledge of male mosquito biology in relation to genetic control programmes.

    PubMed

    Lees, Rosemary Susan; Knols, Bart; Bellini, Romeo; Benedict, Mark Q; Bheecarry, Ambicadutt; Bossin, Hervé Christophe; Chadee, Dave D; Charlwood, Jacques; Dabiré, Roch K; Djogbenou, Luc; Egyir-Yawson, Alexander; Gato, René; Gouagna, Louis Clément; Hassan, Mo'awia Mukhtar; Khan, Shakil Ahmed; Koekemoer, Lizette L; Lemperiere, Guy; Manoukis, Nicholas C; Mozuraitis, Raimondas; Pitts, R Jason; Simard, Frederic; Gilles, Jeremie R L

    2014-04-01

    The enormous burden placed on populations worldwide by mosquito-borne diseases, most notably malaria and dengue, is currently being tackled by the use of insecticides sprayed in residences or applied to bednets, and in the case of dengue vectors through reduction of larval breeding sites or larviciding with insecticides thereof. However, these methods are under threat from, amongst other issues, the development of insecticide resistance and the practical difficulty of maintaining long-term community-wide efforts. The sterile insect technique (SIT), whose success hinges on having a good understanding of the biology and behaviour of the male mosquito, is an additional weapon in the limited arsenal against mosquito vectors. The successful production and release of sterile males, which is the mechanism of population suppression by SIT, relies on the release of mass-reared sterile males able to confer sterility in the target population by mating with wild females. A five year Joint FAO/IAEA Coordinated Research Project brought together researchers from around the world to investigate the pre-mating conditions of male mosquitoes (physiology and behaviour, resource acquisition and allocation, and dispersal), the mosquito mating systems and the contribution of molecular or chemical approaches to the understanding of male mosquito mating behaviour. A summary of the existing knowledge and the main novel findings of this group is reviewed here, and further presented in the reviews and research articles that form this Acta Tropica special issue. PMID:24252487

  20. Ecological niche model of Phlebotomus perniciosus, the main vector of canine leishmaniasis in north-eastern Italy.

    PubMed

    Signorini, Manuela; Cassini, Rudi; Drigo, Michele; Frangipane di Regalbono, Antonio; Pietrobelli, Mario; Montarsi, Fabrizio; Stensgaard, Anna-Sofie

    2014-11-01

    With respect to the epidemiology of leishmaniasis, it is crucial to take into account the ecoclimatic and environmental characteristics that influence the distribution patterns of the vector sand fly species. It is also important to consider the possible impact of on-going climate changes on the emergence of this disease. In order to map the potential distribution of Phlebotomus perniciosus, the main vector species of canine leishmaniasis in north-eastern Italy, geographical information systems tools, ecological niche models (ENM) and remotely sensed environmental data were applied for a retrospective analysis of an entomological survey conducted in north-eastern Italy over 12 years. Sand fly trapping was conducted from 2001 to 2012 in 175 sites in the provinces of Veneto, Friuli-Venezia Giulia and Trentino-Alto Adige. We developed a predictive model of potential distribution of P. perniciosus using the maximum entropy algorithm software, based on seasonal normalized difference vegetation index, day and night land surface temperature, the Corine land cover 2006, a digital elevation model (GTOPO30) and climate layers obtained from the WorldClim database. The MaxEnt prediction found the more suitable habitat for P. perniciosus to be hilly areas (100-300 m above the mean sea level) characterised by temperate climate during the winter and summer seasons, high winter vegetation cover and moderate rainfall during the activity season of vector sand fly. ENM provided a greater understanding of the geographical distribution and ecological requirements of P. perniciosus in the study area, which can be applied for the development of future surveillance strategies. PMID:25545936

  1. A global assembly of adult female mosquito mark-release-recapture data to inform the control of mosquito-borne pathogens

    PubMed Central

    2014-01-01

    Background Pathogen transmission by mosquitos is known to be highly sensitive to mosquito bionomic parameters. Mosquito mark-release-recapture (MMRR) experiments are a standard method for estimating such parameters including dispersal, population size and density, survival, blood feeding frequency and blood meal host preferences. Methods We assembled a comprehensive database describing adult female MMRR experiments. Bibliographic searches were used to build a digital library of MMRR studies and selected data describing the reported outcomes were extracted. Results The resulting database contained 774 unique adult female MMRR experiments involving 58 vector mosquito species from the three main genera of importance to human health: Aedes, Anopheles and Culex. Crude examination of these data revealed patterns associated with geography as well as mosquito genus, consistent with bionomics varying by species-specific life history and ecological context. Recapture success varied considerably and was significantly different amongst genera, with 8, 4 and 1% of adult females recaptured for Aedes, Anopheles and Culex species, respectively. A large proportion of experiments (59%) investigated dispersal and survival and many allowed disaggregation of the release and recapture data. Geographic coverage was limited to just 143 localities around the world. Conclusions This MMRR database is a substantial contribution to the compilation of global data that can be used to better inform basic research and public health interventions, to identify and fill knowledge gaps and to enrich theory and evidence-based ecological and epidemiological studies of mosquito vectors, pathogen transmission and disease prevention. The database revealed limited geographic coverage and a relative scarcity of information for vector species of substantial public health relevance. It represents, however, a wealth of entomological information not previously compiled and of particular interest for mosquito

  2. Evaluation of attractive toxic sugar bait (ATSB)-Barrier for control of vector and nuisance mosquitoes and its effect on non-target organisms in sub-tropical environments in Florida.

    PubMed

    Qualls, Whitney A; Müller, Günter C; Revay, Edita E; Allan, Sandra A; Arheart, Kristopher L; Beier, John C; Smith, Michal L; Scott, Jodi M; Kravchenko, Vasiliy D; Hausmann, Axel; Yefremova, Zoya A; Xue, Rui-De

    2014-03-01

    The efficacy of attractive toxic sugar baits (ATSB) with the active ingredient eugenol, an Environmental Protection Agency exempt compound, was evaluated against vector and nuisance mosquitoes in both laboratory and field studies. In the laboratory, eugenol combined in attractive sugar bait (ASB) solution provided high levels of mortality for Aedes aegypti, Culex quinquefasciatus, and Anopheles quadrimaculatus. Field studies demonstrated significant control: >70% reduction for Aedes atlanticus, Aedes. infirmatus, and Culex nigripalpus and >50% reduction for Anopheles crucians, Uranotaenia sapphirina, Culiseta melanura, and Culex erraticus three weeks post ATSB application. Furthermore, non-target feeding of six insect orders, Hymenoptera, Lepidoptera, Coleoptera, Diptera, Hemiptera, and Orthoptera, was evaluated in the field after application of a dyed-ASB to flowering and non-flowering vegetation. ASB feeding (staining) was determined by dissecting the guts and searching for food dye with a dissecting microscope. The potential impact of ATSB on non-targets, applied on green non-flowering vegetation was low for all non-target groups (0.9%). However, application of the ASB to flowering vegetation resulted in significant staining of the non-target insect orders. This highlights the need for application guidelines to reduce non-target effects. No mortality was observed in laboratory studies with predatory non-targets, spiders, praying mantis, or ground beetles, after feeding for three days on mosquitoes engorged on ATSB. Overall, our laboratory and field studies support the use of eugenol as an active ingredient for controlling important vector and nuisance mosquitoes when used as an ATSB toxin. This is the first study demonstrating effective control of anophelines in non-arid environments which suggest that even in highly competitive sugar rich environments this method could be used for control of malaria in Latin American countries. PMID:24361724

  3. Evaluation of attractive toxic sugar bait (ATSB)—barrier for control of vector and nuisance mosquitoes and its effect on non-target organisms in sub-tropical environments in Florida

    PubMed Central

    Qualls, Whitney A.; Müller, Günter C.; Revay, Edita E.; Allan, Sandra A.; Arheart, Kristopher L.; Beier, John C.; Smith, Michal L.; Scott, Jodi M.; Kravchenko, Vasiliy D.; Hausmann, Axel; Yefremova, Zoya A.; Xue, Rui-De

    2014-01-01

    The efficacy of attractive toxic sugar baits (ATSB) with the active ingredient eugenol, an Environmental Protection Agency exempt compound, was evaluated against vector and nuisance mosquitoes in both laboratory and field studies. In the laboratory, eugenol combined in attractive sugar bait (ASB) solution provided high levels of mortality for Aedes aegypti, Culex quinquefasciatus, and Anopheles quadrimaculatus. Field studies demonstrated significant control: > 70% reduction for Aedes atlanticus, Ae. infirmatus, and Culex nigripalpus and > 50% reduction for An. crucians, Uranotaenia sapphirina, Culiseta melanura, and Cx. erraticus three weeks post ATSB application. Furthermore, non-target feeding of six insect orders, Hymenoptera, Lepidoptera, Coleoptera, Diptera, Hemiptera, and Orthoptera, was evaluated in the field after application of a dyed-ASB to flowering and non-flowering vegetation. ASB feeding (staining) was determined by dissecting the guts and searching for food dye with a dissecting microscope. The potential impact of ATSB on non-targets, applied on green non-flowering vegetation was low for all non-target groups (0.9%). However, application of the ASB to flowering vegetation resulted in significant staining of the non-target insect orders. This highlights the need for application guidelines to reduce non-target effects. No mortality was observed in laboratory studies with predatory non-targets, spiders, praying mantis, or ground beetles, after feeding for three days on mosquitoes engorged on ATSB. Overall, our laboratory and field studies support the use of eugenol as an active ingredient for controlling important vector and nuisance mosquitoes when used as an ATSB toxin. This is the first study demonstrating effective control of anophelines in non-arid environments which suggest that even in highly competitive sugar rich environments this method could be used for control of malaria in Latin American countries. PMID:24361724

  4. Molecular epidemiology of Japanese encephalitis virus in mosquitoes in Taiwan during 2005-2012.

    PubMed

    Su, Chien-Ling; Yang, Cheng-Fen; Teng, Hwa-Jen; Lu, Liang-Chen; Lin, Cheo; Tsai, Kun-Hsien; Chen, Yu-Yu; Chen, Li-Yu; Chang, Shu-Fen; Shu, Pei-Yun

    2014-10-01

    Japanese encephalitis (JE) is a mosquito-borne zoonotic disease caused by the Japanese encephalitis virus (JEV). Pigs and water birds are the main amplifying and maintenance hosts of the virus. In this study, we conducted a JEV survey in mosquitoes captured in pig farms and water bird wetland habitats in Taiwan during 2005 to 2012. A total of 102,633 mosquitoes were collected. Culex tritaeniorhynchus was the most common mosquito species found in the pig farms and wetlands. Among the 26 mosquito species collected, 11 tested positive for JEV by RT-PCR, including Cx. tritaeniorhynchus, Cx. annulus, Anopheles sinensis, Armigeres subalbatus, and Cx. fuscocephala. Among those testing positive, Cx. tritaeniorhynchus was the predominant vector species for the transmission of JEV genotypes I and III in Taiwan. The JEV infection rate was significantly higher in the mosquitoes from the pig farms than those from the wetlands. A phylogenetic analysis of the JEV envelope gene sequences isolated from the captured mosquitoes demonstrated that the predominant JEV genotype has shifted from genotype III to genotype I (GI), providing evidence for transmission cycle maintenance and multiple introductions of the GI strains in Taiwan during 2008 to 2012. This study demonstrates the intense JEV transmission activity in Taiwan, highlights the importance of JE vaccination for controlling the epidemic, and provides valuable information for the assessment of the vaccine's efficacy. PMID:25275652

  5. Molecular Epidemiology of Japanese Encephalitis Virus in Mosquitoes in Taiwan during 2005–2012

    PubMed Central

    Su, Chien-Ling; Yang, Cheng-Fen; Teng, Hwa-Jen; Lu, Liang-Chen; Lin, Cheo; Tsai, Kun-Hsien; Chen, Yu-Yu; Chen, Li-Yu; Chang, Shu-Fen; Shu, Pei-Yun

    2014-01-01

    Japanese encephalitis (JE) is a mosquito-borne zoonotic disease caused by the Japanese encephalitis virus (JEV). Pigs and water birds are the main amplifying and maintenance hosts of the virus. In this study, we conducted a JEV survey in mosquitoes captured in pig farms and water bird wetland habitats in Taiwan during 2005 to 2012. A total of 102,633 mosquitoes were collected. Culex tritaeniorhynchus was the most common mosquito species found in the pig farms and wetlands. Among the 26 mosquito species collected, 11 tested positive for JEV by RT-PCR, including Cx. tritaeniorhynchus, Cx. annulus, Anopheles sinensis, Armigeres subalbatus, and Cx. fuscocephala. Among those testing positive, Cx. tritaeniorhynchus was the predominant vector species for the transmission of JEV genotypes I and III in Taiwan. The JEV infection rate was significantly higher in the mosquitoes from the pig farms than those from the wetlands. A phylogenetic analysis of the JEV envelope gene sequences isolated from the captured mosquitoes demonstrated that the predominant JEV genotype has shifted from genotype III to genotype I (GI), providing evidence for transmission cycle maintenance and multiple introductions of the GI strains in Taiwan during 2008 to 2012. This study demonstrates the intense JEV transmission activity in Taiwan, highlights the importance of JE vaccination for controlling the epidemic, and provides valuable information for the assessment of the vaccine's efficacy. PMID:25275652

  6. Combining two-dimensional gel electrophoresis and metabolomic data in support of dry-season survival in the two main species of the malarial mosquito Anopheles gambiae.

    PubMed

    Hidalgo, K; Mouline, K; Mamai, W; Foucreau, N; Dabiré, K R; Bouchereau, A; Simard, F; Renault, D

    2015-12-01

    In dry savannahs of West-Africa, the malarial mosquitoes of the Anopheles gambiae sensu stricto complex annually survive the harsh desiccating conditions of the dry season. However, the physiological and biochemical mechanisms underlying how these mosquitoes survive such desiccating conditions are still undefined, and controversial. In this context, we provide the first work examining both proteomic and metabolomic changes in the two molecular forms of A. gambiae s.s (M and S forms) experimentally exposed to the rainy and dry season conditions as they experience in the field. Protein abundances of the mosquitoes were measured using a two-dimensional fluorescence difference gel electrophoresis (2D DIGE) coupled with a matrix-assisted laser desorption/ionisation-time of flight (MALDI-TOF) and tandem mass spectrometry (MS) for protein identification. These assays were conducted by Applied Biomics (http://www.appliedbiomics.com, Applied Biomics, Inc. Hayward, CA, USA), and the mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium (http://proteomecentral.proteomexchange.org) via the PRIDE partner repository with the dataset identifier PXD000294. The metabolomic analysis was conducted using both Acquity UPLC(®) system (for amino acid identification), and a gas-chromatography-mass spectrometry platform (for sugars identification). Metabolomic fingerprintings were assessed in the University of Rennes 1, UMR CNRS 6553 EcoBio (France). A detailed interpretation of the obtained data can be found in Hidalgo et al. (2014) [1] (Journal of Insect Physiology (2014)). PMID:26543889

  7. Host preferences in host-seeking and blood-fed mosquitoes in Switzerland.

    PubMed

    Schönenberger, A C; Wagner, S; Tuten, H C; Schaffner, F; Torgerson, P; Furrer, S; Mathis, A; Silaghi, C

    2016-03-01

    The avian zoonotic agent for West Nile virus (WNV) can cause neuroinvasive disease in horses and humans and is expanding its range in Europe. Analyses of the risk for transmission to these hosts in non-endemic areas are necessary. Host preferences of mosquitoes (Diptera: Culicidae), the main vectors of WNV, were determined in Switzerland using animal-baited trap (horse, chickens) experiments at a natural and a periurban site. This was undertaken on four occasions during May-September 2014. In addition, the hosts of 505 blood-fed mosquitoes collected in a zoo and in the field were determined. Mosquito data obtained in the animal bait experiments were corrected for host weight and body surface area and by Kleiber's scaling factor. Collections of 11-14 different mosquito species were achieved with these approaches. Statistically significant host preferences were identified in three species in both approaches. The other species showed opportunistic feeding behaviours to varying extents. Specifically, the invasive species Hulecoeteomyia japonica (= Aedes japonicus) was identified for the first time as feeding on avians in nature. Abundance data, spatiotemporal activity and laboratory vector competence for WNV suggested that, in addition to the main WNV vector Culex pipiens, H. japonica and Aedimorphus vexans (= Aedes vexans) are the most likely candidate bridge vectors for WNV transmission in Switzerland. PMID:26685926

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

    PubMed Central

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

    2012-01-01

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

  9. Maintenance of residual activity of Bt toxin by using natural and synthetic dyes: a novel approach for sustainable mosquito vector control.

    PubMed

    Chandrashekhar, Patil; Rahul, Suryawanshi; Hemant, Borase; Chandrakant, Narkhede; Bipinchandra, Salunke; Satish, Patil

    2015-01-01

    Mosquito control protein from Bacillus thuringiensis gets inactivated with exposure to sunlight. To address this issue, the potential of synthetic and natural dye was investigated as sunlight protectants. Bt SV2 in absence of dyes when exposed to sunlight showed reduced effectiveness against the fourth instars of mosquito larvae. Whereas acriflavin, congo red and violacein were able to maintain 86.4%, 91.6% and 82.2% mosquito larvicidal efficacy of Bt SV2 against IVth instars larvae of Anopheles stephensi Meigen after exposure to sunlight. Similarly, beetroot dye, acriflavin, congo red and violacein maintained 98.4%, 97.1%, 90.8% and 70.7% larvicidal activities against Aedes aegypti Linnaeus after sunlight exposure. Prodigiosin was found to be the best photo-protectant by simultaneously protecting and enhancing Bt activity by 6.16% and 22.16% against A. stephensi and A. aegypti, respectively. Combination of dyes with Bt formulations can be a good strategy for mosquito control programmes in tropical and sub-tropical regions. PMID:25699646

  10. An automated GIS/remotely sensed early warning system to detect elevated populations of vectors of Rift Valley fever, a mosquito-borne emerging virus threat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mosquito transmitted infectious diseases, like eastern equine encephalitis (EEE), Rift Valley fever (RVF), and West Nile virus (WNV), pose an international threat to animal and human health. An introduction of RVF into the U.S. would severely impact wild ungulate populations and the beef and dairy ...

  11. Spatial and temporal distribution of the malaria mosquito Anopheles arabiensis in northern Sudan: influence of environmental factors and implications for vector control

    PubMed Central

    Ageep, Tellal B; Cox, Jonathan; Hassan, M'oawia M; Knols, Bart GJ; Benedict, Mark Q; Malcolm, Colin A; Babiker, Ahmed; El Sayed, Badria B

    2009-01-01

    Background Malaria is an important public health problem in northern Sudan, but little is known about the dynamics of its transmission. Given the characteristic low densities of Anopheles arabiensis and the difficult terrain in this area, future vector control strategies are likely to be based on area-wide integrated pest management (AW-IPM) that may include the sterile insect technique (SIT). To support the planning and implementation of future AW-IPM activities, larval surveys were carried out to provide key data on spatial and seasonal dynamics of local vector populations. Methods Monthly cross-sectional larval surveys were carried out between March 2005 and May 2007 in two localities (Dongola and Merowe) adjacent to the river Nile. A stratified random sampling strategy based on the use of Remote Sensing (RS), Geographical Information Systems (GIS) and the Global Positioning System (GPS) was used to select survey locations. Breeding sites were mapped using GPS and data on larval density and breeding site characteristics were recorded using handheld computers. Bivariate and multivariate logistic regression models were used to identify breeding site characteristics associated with increased risk of presence of larvae. Seasonal patterns in the proportion of breeding sites positive for larvae were compared visually to contemporaneous data on climate and river height. Results Of a total of 3,349 aquatic habitats sampled, 321 (9.6%) contained An. arabiensis larvae. The frequency with which larvae were found varied markedly by habitat type. Although most positive sites were associated with temporary standing water around the margins of the main Nile channel, larvae were also found at brickworks and in areas of leaking pipes and canals – often far from the river. Close to the Nile channel, a distinct seasonal pattern in larval populations was evident and appeared to be linked to the rise and fall of the river level. These patterns were not evident in vector

  12. Insect Repellents: Modulators of mosquito odorant receptor activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mosquitoes vector numerous pathogens that cause diseases including malaria, yellow fever, dengue fever and chikungunya. DEET, IR3535, Picaridin and 2-undecanone are insect repellents that are used to prevent interactions between humans and a broad array of disease vectors including mosquitoes. While...

  13. Mosquitoes established in Lhasa city, Tibet, China

    PubMed Central

    2013-01-01

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

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

    PubMed

    Boštíková, Vanda; Pasdiorová, Markéta; Marek, Jan; Prášil, Petr; Salavec, Miloslav; Sleha, Radek; Střtítecká, Hana; Blažek, Pavel; Hanovcová, Irena; Šošovičková, Renáta; Špliňo, Milan; Smetana, Jan; Chlíbek, Roman; Hytych, Václav; Kuča, Kamil; Boštík, Pavel

    2016-06-01

    Studies focused on arbovirus diseases transmitted by invasive species of mosquitoes have become increasingly significant in recent years, due to the fact that these vectors have successfully migrated to Europe and become established in the region. Mosquitoes, represented by more than 3 200 species, occur naturally worldwide, except in Antarctica. They feed on the blood of warm-blooded animals and by this route, they are capable of transmitting dangerous diseases. Some species can travel a distance of 10 km per night and can fly continuously for up to 4 hours at a speed of 1-2 km/h. Most species are active at night, in the evening or morning. It usually takes a mosquito female about 50 seconds to penetrate the skin of mammals and the subsequent blood meal usually takes about 2.5 minutes. Mosquitoes live for several weeks or months, depending on the environmental conditions. The VectorNet project is a European network of information exchange and sharing of data relating to the geographical distribution of arthropod vectors and transmission of infectious agents between human populations and animals. It aims at the development of strategic plans and vaccination policies which are the main tasks of this time, as well as the development and application of new disinfectants to control vector populations. PMID:27450526

  15. Vector-Host Interactions Governing Epidemiology of West Nile Virus in Southern California

    PubMed Central

    Molaei, Goudarz; Cummings, Robert F.; Su, Tianyun; Armstrong, Philip M.; Williams, Greg A.; Cheng, Min-Lee; Webb, James P.; Andreadis, Theodore G.

    2010-01-01

    Southern California remains an important focus of West Nile virus (WNV) activity, with persistently elevated incidence after invasion by the virus in 2003 and subsequent amplification to epidemic levels in 2004. Eco-epidemiological studies of vectors-hosts-pathogen interactions are of paramount importance for better understanding of the transmission dynamics of WNV and other emerging mosquito-borne arboviruses. We investigated vector-host interactions and host-feeding patterns of 531 blood-engorged mosquitoes in four competent mosquito vectors by using a polymerase chain reaction (PCR) method targeting mitochondrial DNA to identify vertebrate hosts of blood-fed mosquitoes. Diagnostic testing by cell culture, real-time reverse transcriptase-PCR, and immunoassays were used to examine WNV infection in blood-fed mosquitoes, mosquito pools, dead birds, and mammals. Prevalence of WNV antibodies among wild birds was estimated by using a blocking enzyme-linked immunosorbent assay. Analyses of engorged Culex quinquefasciatus revealed that this mosquito species acquired 88.4% of the blood meals from avian and 11.6% from mammalian hosts, including humans. Similarly, Culex tarsalis fed 82% on birds and 18% on mammals. Culex erythrothorax fed on both birds (59%) and mammals (41%). In contrast, Culex stigmatosoma acquired all blood meals from avian hosts. House finches and a few other mostly passeriform birds served as the main hosts for the blood-seeking mosquitoes. Evidence of WNV infection was detected in mosquito pools, wild birds, dead birds, and mammals, including human fatalities during the study period. Our results emphasize the important role of house finches and several other passeriform birds in the maintenance and amplification of WNV in southern California, with Cx. quinquefasciatus acting as both the principal enzootic and “bridge vector” responsible for the spillover of WNV to humans. Other mosquito species, such as Cx. tarsalis and Cx. stigmatosoma, are

  16. Using Wolbachia-based release for suppression of Aedes mosquitoes: insights from genetic data and population simulations.

    PubMed

    Rasić, Gordana; Endersby, Nancy M; Williams, Craig; Hoffmann, Ary A

    2014-07-01

    A novel strategy for suppressing disease transmission by Aedes aegypti, the main vector of dengue, uses releases of mosquitoes infected with the bacterium Wolbachia pipientis. Wolbachia are currently released to interfere with viral transmission, but there is also potential to use strains in mosquito suppression and elimination programs via the deleterious effects of the bacterium on the host. Mosquito suppression depends on target areas being relatively isolated to prevent reinvasion and on local climatic conditions. Here we explored the opportunity for suppression of A. aegypti in central Queensland, Australia, by using microsatellite data and simulations based on CIMSiM models of local weather conditions and breeding container data. Our results indicate that Wolbachia-induced extinctions in central Queensland are possible, although they may eventually be compromised by ongoing mosquito migration between towns until these sources are also suppressed. The results highlight a novel use of deleterious Wolbachia infections to achieve ecological as well as disease-related endpoints. PMID:25154109

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

    PubMed Central

    Laaksonen, Sauli; Solismaa, Milla; Kortet, Raine; Kuusela, Jussi; Oksanen, Antti

    2009-01-01

    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 apparently promote

  18. Insights into host-finding by Culex mosquitoes: New tools for surveillance?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Culex mosquitoes are important vectors of pathogens and parasites causing diseases such as West Nile virus, St. Louis encephalitis, Japanese encephalitis, Venezuelan equine encephalitis and bancroftian filariasis. Surveillance of these species is based on traps using conventional mosquito attractan...

  19. Laboratory observations on the larvicidal efficacy of three plant species against mosquito vectors of malaria, dengue/dengue hemorrhagic fever (DF/DHF) and lymphatic filariasis in the semi-arid desert.

    PubMed

    Bansal, S K; Singh, Karam V; Sharma, Sapna; Sherwani, M R K

    2012-05-01

    Comparative larvicidal efficacy of aqueous and organic solvent extracts from seeds, leaves and flowers of three desert plants viz. Calotropis procera (Aiton), Tephrosia purpurea (L.) Pers. and Prosopis juliflora (Sw.) DC. was evaluated against Anopheles stephensi (Liston), Aedes aegypti (Linnaeus) and Culex quinquefasciatus (Say). For this purpose larvae of all the three mosquito species were reared in the laboratory and studies carried out on late 3rd or early 4th instars using standard WHO technique. Based on concentration mortality data 24 and 48 hr LC50and LC90 values along with their 95% fiducial limits, regression equation, chi-square (chi2)/ heterogeneity of the response were determined by log probit regression analysis. Experiments were carried out with different solvent extracts of seeds of C. procera which revealed that methanol (24 hr LC50: 127.2, 194.8, 361.0) and acetone (229.9, 368.1,193.0 mg l(-1)) extracts were more effective with the three mosquito species, respectively. Petroleum ether extract was effective only on An. stephensi while aqueous extracts were not effective at all with any of the mosquito species (mortality < 10-30%). Tests carried out with methanol extracts of fresh leaves (24 hr LC50: 89.2, 171.2, 369.7) and flowers (24 hr LC50: 94.7,617.3, 1384.0 mg l-(-1)) of Calotropis showed that preparations from fresh parts were 2-3 times more effective as compared to the stored plant parts. Efficacy was less than 10-30% with both An. aegypti and Cx. quinquefasciatus while An. stephensi was still susceptible to extracts from both leaves and flowers even after two years of storage. The 24 hr LC50 values as observed for methanol extracts of seeds of T. purpurea and leaves of P. juliflora were 74.9, 63.2 and 47.0 and 96.2,128.1 and 118.8 mg l(-1) for the above three mosquito species, respectively. Experiments carried out up to 500 mg l-(1) with leaves (T. purpurea) and seeds (P. juliflora) extracts show only up to 10-30% mortality indicating that

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

    PubMed

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

    2016-04-01

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

  1. Avian disease and mosquito vectors in the Kahuku unit of Hawai`i Volcanoes National Park and Ka`u Forest Reserve

    USGS Publications Warehouse

    Gaudioso, Jacqueline; Lapointe, Dennis; Atkinson, Carter T.; Egan, Ariel N.

    2015-01-01

    While avian disease has been well-studied in windward forests of Hawai‘i Island, there have been few studies in leeward Ka‘u. We surveyed four altitudinal sites ranging from 1,200 to 2,200 m asl in the Kahuku Unit of Hawai‘i Volcanoes National Park (Kahuku) and three altitudinal sites ranging from 1,200 to 1,500 m asl in the Ka‘u Forest Reserve (Ka‘u) for the prevalence of avian disease and presence of mosquitoes. We collected blood samples from native and non-native forest birds and screened for avian malaria (Plasmodium relictum) using PCR diagnostics. We examined birds for signs of avian pox (Avipoxvirus sp.), knemidokoptic mange (Knemidokoptes jamaicensis) and feather ectoparasites. We also trapped adult mosquitoes (Culex quinquefasciatus and Aedes japonicus japonicus) and surveyed for available larval habitat. Between September, 2012 and October, 2014, we completed 3,219 hours of mist-netting in Kahuku capturing 515 forest birds and 3,103 hours of mist-netting in Ka‘u capturing 270 forest birds. We screened 750 blood samples for avian malaria. Prevalence of avian malaria in all species was higher in Ka‘u than Kahuku when all sites were combined for each tract. Prevalence of avian malaria in resident Hawai‘i ‘amakihi (Chlorodrepanis virens) was greatest at the lowest elevation sites in Kahuku (26%; 1,201 m asl) and Ka‘u (42%; 1,178 m asl) and in general, prevalence decreased with increasing elevation and geographically from east to west. Significantly higher prevalence was seen in Ka‘u at comparable low and mid elevation sites but not at comparable high elevation sites. The overall presumptive pox prevalence was 1.7% (13/785) for both tracts, and it was higher in native birds than non-native birds, but it was not significant. Presumptive knemidokoptic mange was detected at two sites in lower elevation Kahuku, with prevalence ranging from 2‒4%. The overall prevalence of ectoparasites (Analges and Proctophyllodes spp.) was 6.7% (53

  2. Plant extracts as potential mosquito larvicides.

    PubMed

    Ghosh, Anupam; Chowdhury, Nandita; Chandra, Goutam

    2012-05-01

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

  3. Plant extracts as potential mosquito larvicides

    PubMed Central

    Ghosh, Anupam; Chowdhury, Nandita; Chandra, Goutam

    2012-01-01

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

  4. Mosquito species abundance and diversity in Malindi, Kenya and their potential implication in pathogen transmission.

    PubMed

    Mwangangi, Joseph M; Midega, Janet; Kahindi, Samuel; Njoroge, Laban; Nzovu, Joseph; Githure, John; Mbogo, Charles M; Beier, John C

    2012-01-01

    Mosquitoes (Diptera: Culicidae) are important vectors of human disease-causing pathogens. Mosquitoes are found both in rural and urban areas. Deteriorating infrastructure, poor access to health, water and sanitation services, increasing population density, and widespread poverty contribute to conditions that modify the environment, which directly influences the risk of disease within the urban and peri-urban ecosystem. The objective of this study was to evaluate the mosquito vector abundance and diversity in urban, peri-urban, and rural strata in Malindi along the Kenya coast. The study was conducted in the coastal district of Malindi between January and December 2005. Three strata were selected which were described as urban, peri-urban, and rural. Sampling was done during the wet and dry seasons. Sampling in the wet season was done in the months of April and June to cover the long rainy season and in November and December to cover the short rainy season, while the dry season was between January and March and September and October. Adult mosquito collection was done using Pyrethrum Spray Collection (PSC) and Centers for Disease Control and Prevention (CDC) light traps inside houses and specimens were identified morphologically. In the three strata (urban, peri-urban, and rural), 78.5% of the total mosquito (n = 7,775) were collected using PSC while 18.1% (n = 1,795) were collected using the CDC light traps. Using oviposition traps, mosquito eggs were collected and reared in the insectary which yielded 329 adults of which 83.8% (n = 276) were Aedes aegypti and 16.2% (n = 53) were Culex quinquefasciatus. The mosquito distribution in the three sites varied significantly in each collection site. Anopheles gambiae, Anopheles funestus and Anopheles coustani were predominant in the rural stratum while C. quinquefasciatus was mostly found in urban and peri-urban strata. However, using PSC and CDC light trap collection techniques, A. aegypti was only found

  5. Antimicrobial activity of mosquito cecropin peptides against Francisella.

    PubMed

    Kaushal, Akanksha; Gupta, Kajal; Shah, Ruhee; van Hoek, Monique L

    2016-10-01

    Francisella tularensis is the cause of the zoonotic disease tularemia. In Sweden and Scandinavia, epidemiological studies have implicated mosquitoes as a vector. Prior research has demonstrated the presence of Francisella DNA in infected mosquitoes but has not shown definitive transmission of tularemia from a mosquito to a mammalian host. We hypothesized that antimicrobial peptides, an important component of the innate immune system of higher organisms, may play a role in mosquito host-defense to Francisella. We established that Francisella sp. are susceptible to two cecropin antimicrobial peptides derived from the mosquito Aedes albopictus as well as Culex pipiens. We also demonstrated induced expression of Aedes albopictus antimicrobial peptide genes by Francisella infection C6/36 mosquito cell line. We demonstrate that mosquito antimicrobial peptides act against Francisella by disrupting the cellular membrane of the bacteria. Thus, it is possible that antimicrobial peptides may play a role in the inability of mosquitoes to establish an effective natural transmission of tularemia. PMID:27235883

  6. Assessing the optimal virulence of malaria‐targeting mosquito pathogens: a mathematical study of engineered Metarhizium anisopliae

    PubMed Central

    2014-01-01

    Background Metarhizium anisopliae is a naturally occurring fungal pathogen of mosquitoes. Recently, Metarhizium has been engineered to act against malaria by directly killing the disease agent within mosquito vectors and also effectively blocking onward transmission. It has been proposed that efforts should be made to minimize the virulence of the fungal pathogen, in order to slow the development of resistant mosquitoes following an actual deployment. Results Two mathematical models were developed and analysed to examine the efficacy of the fungal pathogen. It was found that, in many plausible scenarios, the best effects are achieved with a reduced or minimal pathogen virulence, even if the likelihood of resistance to the fungus is negligible. The results for both models depend on the interplay between two main effects: the ability of the fungus to reduce the mosquito population, and the ability of fungus‐infected mosquitoes to compete for resources with non‐fungus‐infected mosquitoes. Conclusions The results indicate that there is no obvious choice of virulence for engineered Metarhizium or similar pathogens, and that all available information regarding the population ecology of the combined mosquito‐fungus system should be carefully considered. The models provide a basic framework for examination of anti‐malarial mosquito pathogens that should be extended and improved as new laboratory and field data become available. PMID:24397503

  7. Oviposition strategies of temporary pool mosquitoes in relation to weather, tidal regime and land use in a temperate wetland.

    PubMed

    Cardo, M V; Vezzani, D; Carbajo, A E

    2012-12-01

    Wetlands have traditionally been associated with harbouring mosquitoes, a well-known nuisance and vectors of diseases. Within mosquito life cycle, oviposition is a determinant event by shaping their individual fitness and vectorial capacity. The study was conducted in one of the main temperate wetlands in South America. We used Generalized Linear Models to study the relation between temperature, precipitation, tidal regime, land use, microenvironment, and the occurrence of floodwater (Ochlerotatus and Psorophora spp.) and raft-laying (Culex and Uranotaenia spp.) mosquitoes using temporary pools as larval habitats. Pool occurrence was negatively associated with temperature, and positively related to precipitation and high tides. As regards the land use, it was lowest in domestic areas and plantations, intermediate in secondary forests, and highest in marshes. Each oviposition strategy was best modelled as a function of different environmental factors. The occurrence of floodwater mosquitoes was positively associated with high cumulative precipitation and low tide records. Raft-laying mosquitoes were related to low temperature records, while the effect of flooding varied with the land use. In view of these results, physical (water inputs and movement), chemical, and biological (egg and larval flushing, and predatory interactions) considerations are given to provide insight in the oviposition patterns of mosquitoes occurring in this complex wetland. We finally propose the generation of a tidal flow as a control measure against floodwater mosquitoes, which are the most anthropophilic in the study area. PMID:22647341

  8. Spatial model for transmission of mosquito-borne diseases

    NASA Astrophysics Data System (ADS)

    Kon, Cynthia Mui Lian; Labadin, Jane

    2015-05-01

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

  9. The Effect of Deltamethrin-treated Net Fencing around Cattle Enclosures on Outdoor-biting Mosquitoes in Kumasi, Ghana

    PubMed Central

    Maia, Marta Ferreira; Abonuusum, Ayimbire; Lorenz, Lena Maria; Clausen, Peter-Henning; Bauer, Burkhard; Garms, Rolf; Kruppa, Thomas

    2012-01-01

    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/m2) 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. PMID:23029245

  10. North American wetlands and mosquito control.

    PubMed

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

    2012-12-01

    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

  11. North American Wetlands and Mosquito Control

    PubMed Central

    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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  13. Hydrology and Mosquito Population Dynamics around a Hydropower Reservoir in Africa

    NASA Astrophysics Data System (ADS)

    Endo, N.; Eltahir, E. A.

    2013-12-01

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

  14. History of Aedes mosquitoes in Hawaii.

    PubMed

    Winchester, Jonathan C; Kapan, Durrell D

    2013-06-01

    As a geographically isolated island chain with no native mosquitoes, Hawaii is a model for examining the mechanisms behind insect vector invasions and their subsequent interactions with each other and with human populations. The yellow fever mosquito, Aedes aegypti, and the Asian tiger mosquito, Ae. albopictus, have been responsible for epidemics of dengue in Hawaii. As one of the world's earliest locations to be invaded by both species, Hawaii's history is particularly relevant because both species are currently invading new areas worldwide and are implicated in outbreaks of emergent or reemergent pathogens such as dengue, chikungunya, and yellow fever. Here we analyze the historical records of mosquito introductions in order to understand the factors that have led to the current distribution of these 2 mosquitoes in the Hawaiian Islands. PMID:23923330

  15. Mosquitocidal and water purification properties of Cynodon dactylon, Aloe vera, Hemidesmus indicus and Coleus amboinicus leaf extracts against the mosquito vectors.

    PubMed

    Arjunan, Nareshkumar; Murugan, Kadarkarai; Madhiyazhagan, Pari; Kovendan, Kalimuthu; Prasannakumar, Kanagarajan; Thangamani, Sundaram; Barnard, Donald R

    2012-04-01

    Ethanolic extracts of Cynodon dactylon, Aloe vera, Hemidesmus indicus and Coleus amboinicus were tested for their toxicity effect on the third-instar larvae of Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti. The leaves of C. dactylon, A. vera, H. indicus and C. amboinicus were collected from natural habitats (forests) in Western Ghats, Tamil Nadu, India. A total of 250 g of fresh, mature leaves were rinsed with distilled water and dried in shade. The dried leaves were put in Soxhlet apparatus and extract prepared using 100% ethanol for 72 h at 30-40°C. Dried residues were obtained from 100 g of extract evaporated to dryness in rotary vacuum evaporator. Larvicidal properties of ethanolic leaf extracts showed that the extracts are effective as mosquito control agents. The larval mortality was observed after 24 h exposure. No mortality was observed in the control. The median lethal concentration (LC(50)) values observed for the larvicidal activities are 0.44%, 0.51%, 0.59% and 0.68% for extracts of C. dactylon, A. vera, H. indicus and C. amboinicus, respectively. The observed mortality were statistically significant at P < 0.05 level. C. dactylon showed the highest mortality rate against the three species of mosquito larvae in laboratory and field. The selected plants were shown to exhibit water purification properties. Water quality parameters such as turbidity, pH and water clarity were analyzed in the water samples (pre-treatment and post-treatment of plant extracts) taken from the different breeding sites of mosquitoes. Water colour, turbidity and pH were reduced significantly after treatment with C. dactylon (13 HU, 31.5 mg/l and 6.9), H. indicus (13.8 HU, 33 mg/l and 7.1), A. vera (16 HU, 33.8 mg/l and 7.4) and C. amboinicus (21 HU, 35 mg/l and 7.5) extracts. The study proved that the extracts of C. dactylon, A. vera, H. indicus and C. amboinicus have both mosquitocidal and water sedimentation properties. PMID:21947308

  16. Mosquito development and biological control in a macrophyte-based wastewater treatment plant.

    PubMed

    Kengne Noumsi, I M; Akoa, A; Atangana Eteme, R; Nya, J; Ngniado, P; Fonkou, T; Brissaud, F

    2005-01-01

    A one-year study of the proliferation of mosquito in a Pistia stratiotes-based waste stabilization ponds in Cameroon revealed that Mansonia and Culex were the main breeding genera with about 55% and 42% of the total imagoes respectively. Though the ponds represent a favorable breeding ground for mosquitoes, only 0.02% of captured imagoes was Anopheles gambiae, suggesting that this wastewater treatment plant does not significantly contribute to the development of the malaria vector in the area. Gambusia sp. introduced to control mosquito population in the ponds acclimatized relatively well in most of the ponds (B3-B7) and their feeding rate without any diet ranged from 15.0 to 50.2 larvae/day for a single fish. PMID:16114683

  17. Inside Flow of Mosquito's Proboscis

    NASA Astrophysics Data System (ADS)

    Kikuchi, Kenji; Terada, Nobuyuki; Mochizuki, Osamu

    2006-11-01

    Mosquito has a magnificent pump mechanism which has been never achieved by technology. We want to apply this high performance mechanism to a micro-TAS system which is designed for a daily check of blood to keep a human health. We need a high powered pump similar to a mosquito's sucking blood mechanism and a low-resistance micro channel mimicked a surface of proboscis. The details of mosquito's pump mechanism, however, have not been ascertained yet. Therefore we tried to investigate the mosquito's pump mechanism by measuring the flow due to suction. A visualization of flow was done by a confocal micro-PIV system. We could analyze the velocity vector profile in the proboscis. The velocity distribution in the proboscis is necessary to estimate the friction drag. In the experiment, a live mosquito was fixed on the glass plate and fed nano-particles near the tip of proboscis. We found that the inside flow of proboscis deviate from Hargen-Poisueuille Flow. It indicates that the surface of inside proboscis has unknown fact for the friction drag reduction.

  18. [The recurring necessity of mosquito surveillance and research].

    PubMed

    Kampen, Helge; Werner, Doreen

    2015-10-01

    Hematophagous arthropods and the diseases associated with them represent a growing threat to human and animal health in Europe. After the eradication of endemic malaria from Europe in the middle of the last century, there has been a resurgence of mosquitoes as significant vectors of disease agents under the influence of continuing globalisation, as exotic species and mosquito-borne pathogens are being introduced with increasing frequency. At present, southern Europe is particularly affected by disease outbreaks and cases, but invasive mosquito species, including efficient vectors, have also emerged in Germany. While there is considerable knowledge on the vector potential of many tropical and subtropical mosquito species, corresponding data on the indigenous mosquito species are scarce. Exceptions are the Anopheles species, which were already vectors of malaria parasites in historic Europe. It must be assumed, however, that many further indigenous species are able to transmit pathogens under certain conditions and will by all means gain vector competence under a scenario of climate warming. Thus, the permanent surveillance of mosquitoes and mosquito-borne disease agents is paramount for the purposes of conducting risk analyses and modelling, in addition to research work addressing the conditions of the spread of vectors and pathogens and of pathogen transmission. Only ample data can facilitate taking appropriate prophylactic action and designing control strategies. International health organizations have realised this and started to promote data collection on mosquitoes and mosquito-borne diseases in the EU. At a national levels, authorities are more reluctant, although, similar to other fields of health, it has been shown for mosquito-borne diseases that preventive measures are more cost-saving than disease case management and the coverage of follow-up costs. The present article is intended to illustrate the necessity of the re-intensification of mosquito

  19. Approaches to passive mosquito surveillance in the EU.

    PubMed

    Kampen, Helge; Medlock, Jolyon M; Vaux, Alexander G C; Koenraadt, Constantianus J M; van Vliet, Arnold J H; Bartumeus, Frederic; Oltra, Aitana; Sousa, Carla A; Chouin, Sébastien; Werner, Doreen

    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 to assess the current species occurrence, distribution and, when possible, abundance, in order to permit the early detection of invasive species and the spread of competent vectors. As active mosquito collection, e.g. by trapping adults, dipping preimaginal developmental stages or ovitrapping, is usually cost-, time- and labour-intensive and can cover only small parts of a country, passive data collection approaches are gradually being integrated into monitoring programmes. Thus, scientists in several EU member states have recently initiated programmes for mosquito data collection and analysis that make use of sources other than targeted mosquito collection. While some of them extract mosquito distribution data from zoological databases established in other contexts, community-based approaches built upon the recognition, reporting, collection and submission of mosquito specimens by citizens are becoming more and more popular and increasingly support scientific research. Based on such reports and submissions, new populations, extended or new distribution areas and temporal activity patterns of invasive and native mosquito species were found. In all cases, extensive media work and communication with the participating individuals or groups was fundamental for success. The presented projects demonstrate that passive approaches are powerful tools to survey the mosquito fauna in order to supplement active mosquito surveillance strategies and render them more focused. Their ability to continuously produce biological data permits the early recognition of changes in the mosquito fauna that may have an impact on biting nuisance and the risk of pathogen transmission associated

  20. Malaria Parasites Produce Volatile Mosquito Attractants

    PubMed Central

    Kelly, Megan; Su, Chih-Ying; Schaber, Chad; Crowley, Jan R.; Hsu, Fong-Fu; Carlson, John R.

    2015-01-01

    ABSTRACT The malaria parasite Plasmodium falciparum contains a nonphotosynthetic plastid organelle that possesses plant-like metabolic pathways. Plants use the plastidial isoprenoid biosynthesis pathway to produce volatile odorants, known as terpenes. In this work, we describe the volatile chemical profile of cultured malaria parasites. Among the identified compounds are several plant-like terpenes and terpene derivatives, including known mosquito attractants. We establish the molecular identity of the odorant receptors of the malaria mosquito vector Anopheles gambiae, which responds to these compounds. The malaria parasite produces volatile signals that are recognized by mosquitoes and may thereby mediate host attraction and facilitate transmission. PMID:25805727

  1. The Impact of Wolbachia on Virus Infection in Mosquitoes

    PubMed Central

    Johnson, Karyn N.

    2015-01-01

    Mosquito-borne viruses such as dengue, West Nile and chikungunya viruses cause significant morbidity and mortality in human populations. Since current methods are not sufficient to control disease occurrence, novel methods to control transmission of arboviruses would be beneficial. Recent studies have shown that virus infection and transmission in insects can be impeded by co-infection with the bacterium Wolbachia pipientis. Wolbachia is a maternally inherited endosymbiont that is commonly found in insects, including a number of mosquito vector species. In Drosophila, Wolbachia mediates antiviral protection against a broad range of RNA viruses. This discovery pointed to a potential strategy to interfere with mosquito transmission of arboviruses by artificially infecting mosquitoes with Wolbachia. This review outlines research on the prevalence of Wolbachia in mosquito vector species and the impact of antiviral effects in both naturally and artificially Wolbachia-infected mosquitoes. PMID:26556361

  2. Combining Hydrology and Mosquito Population Models to Identify the Drivers of Rift Valley Fever Emergence in Semi-Arid Regions of West Africa

    PubMed Central

    Soti, Valérie; Tran, Annelise; Degenne, Pascal; Chevalier, Véronique; Lo Seen, Danny; Thiongane, Yaya; Diallo, Mawlouth; Guégan, Jean-François; Fontenille, Didier

    2012-01-01

    Background Rift Valley fever (RVF) is a vector-borne viral zoonosis of increasing global importance. RVF virus (RVFV) is transmitted either through exposure to infected animals or through bites from different species of infected mosquitoes, mainly of Aedes and Culex genera. These mosquitoes are very sensitive to environmental conditions, which may determine their presence, biology, and abundance. In East Africa, RVF outbreaks are known to be closely associated with heavy rainfall events, unlike in the semi-arid regions of West Africa where the drivers of RVF emergence remain poorly understood. The assumed importance of temporary ponds and rainfall temporal distribution therefore needs to be investigated. Methodology/Principal Findings A hydrological model is combined with a mosquito population model to predict the abundance of the two main mosquito species (Aedes vexans and Culex poicilipes) involved in RVFV transmission in Senegal. The study area is an agropastoral zone located in the Ferlo Valley, characterized by a dense network of temporary water ponds which constitute mosquito breeding sites. The hydrological model uses daily rainfall as input to simulate variations of pond surface areas. The mosquito population model is mechanistic, considers both aquatic and adult stages and is driven by pond dynamics. Once validated using hydrological and entomological field data, the model was used to simulate the abundance dynamics of the two mosquito species over a 43-year period (1961–2003). We analysed the predicted dynamics of mosquito populations with regards to the years of main outbreaks. The results showed that the main RVF outbreaks occurred during years with simultaneous high abundances of both species. Conclusion/Significance Our study provides for the first time a mechanistic insight on RVFV transmission in West Africa. It highlights the complementary roles of Aedes vexans and Culex poicilipes mosquitoes in virus transmission, and recommends the

  3. Dengue Vectors and their Spatial Distribution

    PubMed Central

    Higa, Yukiko

    2011-01-01

    The distribution of dengue vectors, Ae. aegypti and Ae. albopictus, is affected by climatic factors. In addition, since their life cycles are well adapted to the human environment, environmental changes resulting from human activity such as urbanization exert a great impact on vector distribution. The different responses of Ae. aegypti and Ae albopictus to various environments result in a difference in spatial distribution along north-south and urban-rural gradients, and between the indoors and outdoors. In the north-south gradient, climate associated with survival is an important factor in spatial distribution. In the urban-rural gradient, different distribution reflects a difference in adult niches and is modified by geographic and human factors. The direct response of the two species to the environment around houses is related to different spatial distribution indoors and outdoors. Dengue viruses circulate mainly between human and vector mosquitoes, and the vector presence is a limiting factor of transmission. Therefore, spatial distribution of dengue vectors is a significant concern in the epidemiology of the disease. Current technologies such as GIS, satellite imagery and statistical models allow researchers to predict the spatial distribution of vectors in the changing environment. Although it is difficult to confirm the actual effect of environmental and climate changes on vector abundance and vector-borne diseases, environmental changes caused by humans and human behavioral changes due to climate change can be expected to exert an impact on dengue vectors. Longitudinal monitoring of dengue vectors and viruses is therefore necessary. PMID:22500133

  4. Diversity and function of bacterial microbiota in the mosquito holobiont

    PubMed Central

    2013-01-01

    Mosquitoes (Diptera: Culicidae) have been shown to host diverse bacterial communities that vary depending on the sex of the mosquito, the developmental stage, and ecological factors. Some studies have suggested a potential role of microbiota in the nutritional, developmental and reproductive biology of mosquitoes. Here, we present a review of the diversity and functions of mosquito-associated bacteria across multiple variation factors, emphasizing recent findings. Mosquito microbiota is considered in the context of possible extended phenotypes conferred on the insect hosts that allow niche diversification and rapid adaptive evolution in other insects. These kinds of observations have prompted the recent development of new mosquito control methods based on the use of symbiotically-modified mosquitoes to interfere with pathogen transmission or reduce the host life span and reproduction. New opportunities for exploiting bacterial function for vector control are highlighted. PMID:23688194

  5. RIFT VALLEY FEVER: PREPARING FOR POTENTIAL NEW MOSQUITO-BORNE DISEASES IN THE U.S. WITH A VECTOR SURVEILLANCE SYSTEM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this symposium we have discussed four diseases that are emerging threats in the U.S., and it may be concluded that in our best defense knowing the vector is as important as knowing the disease. Rift Valley fever, Dengue, and JEE are but a few of the many emerging diseases that we can prepare for...

  6. Mosquito cytogenetics

    PubMed Central

    Kitzmiller, James B.

    1963-01-01

    Although an intensified interest in mosquito cytogenetics in the past decade has produced a number of contributions to knowledge on this subject, the available information is still superficial and limited to a few mosquito species only. The author of this review summarizes the research done in this field between 1953 and 1962. The following are some of the achievements and some of the gaps that remain to be filled. Karyotypes of several species of Anopheles, Aedes and Culex conform to the general pattern 2n=6, with heterosomes distinguishable only in Anopheles. At least three different karyotypes are present in Anopheles. Salivary gland chromosome maps are now available for several anopheline species, but are still lacking for Culex and Aedes. No precise correlation may yet be made between the frequency of chromosomal aberrations and the degree of insecticide-resistance. Sexual differences in the salivary X-chromosomes have been reported for several species of Anopheles. Chromosomal polymorphism is common in some anophelines, but rare in others. Chromosomal mutation has been induced by means of X-rays. In his conclusions, the author stresses that prospects are especially good for evolutionary and genetic studies involving chromosomal polymorphism. PMID:14058227

  7. ChAd63-MVA–vectored Blood-stage Malaria Vaccines Targeting MSP1 and AMA1: Assessment of Efficacy Against Mosquito Bite Challenge in Humans

    PubMed Central

    Sheehy, Susanne H; Duncan, Christopher JA; Elias, Sean C; Choudhary, Prateek; Biswas, Sumi; Halstead, Fenella D; Collins, Katharine A; Edwards, Nick J; Douglas, Alexander D; Anagnostou, Nicholas A; Ewer, Katie J; Havelock, Tom; Mahungu, Tabitha; Bliss, Carly M; Miura, Kazutoyo; Poulton, Ian D; Lillie, Patrick J; Antrobus, Richard D; Berrie, Eleanor; Moyle, Sarah; Gantlett, Katherine; Colloca, Stefano; Cortese, Riccardo; Long, Carole A; Sinden, Robert E; Gilbert, Sarah C; Lawrie, Alison M; Doherty, Tom; Faust, Saul N; Nicosia, Alfredo; Hill, Adrian VS; Draper, Simon J

    2012-01-01

    The induction of cellular immunity, in conjunction with antibodies, may be essential for vaccines to protect against blood-stage infection with the human malaria parasite Plasmodium falciparum. We have shown that prime-boost delivery of P. falciparum blood-stage antigens by chimpanzee adenovirus 63 (ChAd63) followed by the attenuated orthopoxvirus MVA is safe and immunogenic in healthy adults. Here, we report on vaccine efficacy against controlled human malaria infection delivered by mosquito bites. The blood-stage malaria vaccines were administered alone, or together (MSP1+AMA1), or with a pre-erythrocytic malaria vaccine candidate (MSP1+ME-TRAP). In this first human use of coadministered ChAd63-MVA regimes, we demonstrate immune interference whereby responses against merozoite surface protein 1 (MSP1) are dominant over apical membrane antigen 1 (AMA1) and ME-TRAP. We also show that induction of strong cellular immunity against MSP1 and AMA1 is safe, but does not impact on parasite growth rates in the blood. In a subset of vaccinated volunteers, a delay in time to diagnosis was observed and sterilizing protection was observed in one volunteer coimmunized with MSP1+AMA1—results consistent with vaccine-induced pre-erythrocytic, rather than blood-stage, immunity. These data call into question the utility of T cell-inducing blood-stage malaria vaccines and suggest that the focus should remain on high-titer antibody induction against susceptible antigen targets. PMID:23089736

  8. Genetic control of Aedes mosquitoes.

    PubMed

    Alphey, Luke; McKemey, Andrew; Nimmo, Derric; Neira Oviedo, Marco; Lacroix, Renaud; Matzen, Kelly; Beech, Camilla

    2013-06-01

    Aedes mosquitoes include important vector species such as Aedes aegypti, the major vector of dengue. Genetic control methods are being developed for several of these species, stimulated by an urgent need owing to the poor effectiveness of current methods combined with an increase in chemical pesticide resistance. In this review we discuss the various genetic strategies that have been proposed, their present status, and future prospects. We focus particularly on those methods that are already being tested in the field, including RIDL and Wolbachia-based approaches. PMID:23816508

  9. Genetic control of Aedes mosquitoes

    PubMed Central

    Alphey, Luke; McKemey, Andrew; Nimmo, Derric; Neira Oviedo, Marco; Lacroix, Renaud; Matzen, Kelly; Beech, Camilla

    2013-01-01

    Aedes mosquitoes include important vector species such as Aedes aegypti, the major vector of dengue. Genetic control methods are being developed for several of these species, stimulated by an urgent need owing to the poor effectiveness of current methods combined with an increase in chemical pesticide resistance. In this review we discuss the various genetic strategies that have been proposed, their present status, and future prospects. We focus particularly on those methods that are already being tested in the field, including RIDL and Wolbachia-based approaches. PMID:23816508

  10. Dynamics of Bacterial Community Composition in the Malaria Mosquito's Epithelia

    PubMed Central

    Tchioffo, Majoline T.; Boissière, Anne; Abate, Luc; Nsango, Sandrine E.; Bayibéki, Albert N.; Awono-Ambéné, Parfait H.; Christen, Richard; Gimonneau, Geoffrey; Morlais, Isabelle

    2016-01-01

    The Anopheles midgut hosts diverse bacterial communities and represents a complex ecosystem. Several evidences indicate that mosquito midgut microbiota interferes with malaria parasite transmission. However, the bacterial composition of salivary glands and ovaries, two other biologically important tissues, has not been described so far. In this study, we investigated the dynamics of the bacterial communities in the mosquito tissues from emerging mosquitoes until 8 days after a blood meal containing Plasmodium falciparum gametocytes and described the temporal colonization of the mosquito epithelia. Bacterial communities were identified in the midgut, ovaries, and salivary glands of individual mosquitoes using pyrosequencing of the 16S rRNA gene. We found that the mosquito epithelia share a core microbiota, but some bacteria taxa were more associated with one or another tissue at a particular time point. The bacterial composition in the tissues of emerging mosquitoes varied according to the breeding site, indicating that some bacteria are acquired from the environment. Our results revealed temporal variations in the bacterial community structure, possibly as a result of the mosquito physiological changes. The abundance of Serratia significantly correlated with P. falciparum infection both in the midgut and salivary glands of malaria challenged mosquitoes, which suggests that interactions occur between microbes and parasites. These bacteria may represent promising targets for vector control strategies. Overall, this study points out the importance of characterizing bacterial communities in malaria mosquito vectors. PMID:26779155

  11. Do capture data from mosquito traps represent reality?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Collectively, the effects of mechanical trap style, the method of trap placement in the field, mosquito activity phase, and other biological phenomena are manifest as sample bias that leads to vector detection failure(s) and/or erroneous predictions of mosquito activity. The goal of this research i...

  12. Genetics of War and Truce between Mosquitos and Emerging Viruses.

    PubMed

    Hwang, Jesse; Jurado, Kellie Ann; Fikrig, Erol

    2016-05-11

    Arboviruses have made unexpected reappearances in recent years. Unlike viruses that undergo direct transmission, arboviruses utilize an arthropod vector (e.g., mosquitos, sandflies, and ticks) to spread throughout human populations. Here, we provide a snapshot of mosquito susceptibility to viral infection using flaviviruses, alphaviruses, and bunyaviruses as examples of emerging pathogens of global health relevance. PMID:27173926

  13. Public Health Response to Aedes aegypti and Ae. albopictus Mosquitoes Invading California, USA

    PubMed Central

    Kramer, Vicki; Yoshimizu, Melissa Hardstone; Metzger, Marco; Hu, Renjie; Padgett, Kerry; Vugia, Duc J.

    2015-01-01

    Aedes aegypti and Ae. albopictus mosquitoes, primary vectors of dengue and chikungunya viruses, were recently detected in California, USA. The threat of potential local transmission of these viruses increases as more infected travelers arrive from affected areas. Public health response has included enhanced human and mosquito surveillance, education, and intensive mosquito control. PMID:26401891

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  15. The effects of zooprophylaxis and other mosquito control measures against malaria in Nouna, Burkina Faso

    PubMed Central

    2009-01-01

    Background In the absence of large scale, organized vector control programmes, individual protective measures against mosquitoes are essential for reducing the transmission of diseases like malaria. Knowledge of the types and effectiveness of mosquito control methods used by households can aid in the development and promotion of preventive measures. Methods A matched, population-based case control study was carried out in the semi-urban region of Nouna, Burkina Faso. Surveys and mosquito captures were conducted for each participating household. Data were analysed using conditional logistic regression and Pearson's product-moment correlations. Results In Nouna, Burkina Faso, the main types of reported mosquito control measures used included sleeping under bed nets (insecticide-treated and untreated) and burning mosquito coils. Most of the study households kept animals within the compound or house at night. Insecticide house sprays, donkeys, rabbits and pigs were significantly associated with a reduced risk of malaria only in univariate analyses. Conclusion Given the conflicting results of the effects of zooprophylaxis from previous studies, other community-based preventive measures, such as bed nets, coils and insecticide house-spraying, may be of more benefit. PMID:20003189

  16. Biofabrication of Ag nanoparticles using Sterculia foetida L. seed extract and their toxic potential against mosquito vectors and HeLa cancer cells.

    PubMed

    Rajasekharreddy, Pala; Rani, Pathipati Usha

    2014-06-01

    A one-step and eco-friendly process for the synthesis of silver-(protein-lipid) nanoparticles (Ag-PL NPs) (core-shell) has been developed using the seed extract from wild Indian Almond tree, Sterculia foetida (L.) (Sterculiaceae). The reaction temperature played a major role in controlling the size and shell formation of NPs. The amount of NPs synthesized and qualitative characterization was done by UV-vis spectroscopy and transmission electron microscopy (TEM), respectively. TEM studies exhibited controlled dispersity of spherical shaped NPs with an average size of 6.9±0.2nm. Selected area electron diffraction (SAED) and X-ray diffraction (XRD) revealed 'fcc' phase and crystallinity of the particles. X-ray photoelectron spectroscopy (XPS) was used to identify the protein-lipid (PL) bilayer that appears as a shell around the Ag core particles. The thermal stability of the Ag-PL NPs was examined using thermogravimetric analysis (TGA). Further analysis was carried out by using Fourier transform infrared spectroscopy (FTIR), where the spectra provided evidence for the presence of proteins and lipid moieties ((2n-octylcycloprop-1-enyl)-octanoic acid (I)), and their role in synthesis and stabilization of Ag NPs. This is the first report of plant seed assisted synthesis of PL conjugated Ag NPs. These formed Ag-PL NPs showed potential mosquito larvicidal activity against Aedes aegypti (L.), Anopheles stephensi Liston and Culex quinquefasciatus Say. These Ag-PL NPs can also act as promising agents in cancer therapy. They exhibited anti-proliferative activity against HeLa cancer cell lines and a promising toxicity was observed in a dose dependent manner. Toxicity studies were further supported by the cellular DNA fragmentation in the Ag-PL NPs treated HeLa cells. PMID:24863217

  17. Resistance management strategies in malaria vector mosquito control. Baseline data for a large-scale field trial against Anopheles albimanus in Mexico.

    PubMed

    Penilla, R P; Rodríguez, A D; Hemingway, J; Torres, J L; Arredondo-Jiménez, J I; Rodríguez, M H

    1998-07-01

    A high level of DDT resistance and low levels of resistance to organophosphorus, carbamate and pyrethroid insecticides were detected by discriminating dose assays in field populations of Anopheles albimanus in Chiapas, southern Mexico, prior to a large-scale resistance management project described by Hemingway et al. (1997). Biochemical assays showed that the DDT resistance was caused by elevated levels of glutathione S-transferase (GST) activity leading to increased rates of metabolism of DDT to DDE. The numbers of individuals with elevated GST and DDT resistance were well correlated, suggesting that this is the only major DDT resistance mechanism in this population. The carbamate resistance in this population is conferred by an altered acetylcholinesterase (AChE)-based resistance mechanism. The level of resistance observed in the bioassays correlates with the frequency of individuals homozygous for the altered AChE allele. This suggests that the level of resistance conferred by this mechanism in its heterozygous state is below the level of detection by the WHO carbamate discriminating dosage bioassay. The low levels of organophosphate (OP) and pyrethroid resistance could be conferred by either the elevated esterase or monooxygenase enzymes. The esterases were elevated only with the substrate pNPA, and are unlikely to be causing broad spectrum OP resistance. The altered AChE mechanism may also be contributing to the OP but not the pyrethroid resistance. Significant differences in resistance gene frequencies were obtained from the F1 mosquitoes resulting from adults obtained by different collection methods. This may be caused by different insecticide selection pressures on the insects immediately prior to collection, or may be an indication that the indoor- and outdoor-resting A. albimanus collections are not from a randomly mating single population. The underlying genetic variability of the populations is currently being investigated by molecular methods. PMID

  18. Bromeliad-inhabiting mosquitoes in an urban botanical garden of dengue endemic Rio de Janeiro--are bromeliads productive habitats for the invasive vectors Aedes aegypti and Aedes albopictus?

    PubMed

    Mocellin, Márcio Goulart; Simões, Taynãna César; Nascimento, Teresa Fernandes Silva do; Teixeira, Maria Lucia França; Lounibos, Leon Philip; Oliveira, Ricardo Lourenço de

    2009-12-01

    Immatures of both Aedes aegypti and Aedes albopictus have been found in water-holding bromeliad axils in Brazil. Removal of these plants or their treatment with insecticides in public and private gardens have been undertaken during dengue outbreaks in Brazil despite uncertainty as to their importance as productive habitats for dengue vectors. From March 2005-February 2006, we sampled 120 randomly selected bromeliads belonging to 10 species in a public garden less than 200 m from houses in a dengue-endemic neighborhood in Rio de Janeiro. A total of 2,816 mosquito larvae and pupae was collected, with an average of 5.87 immatures per plant per collection. Culex (Microculex) pleuristriatus and Culex spp of the Ocellatus Group were the most abundant culicid species, found in all species of bromeliads; next in relative abundance were species of the genus Wyeomyia. Only two individuals of Ae. aegypti (0.07%) and five of Ae. albopictus(0.18%) were collected from bromeliads. By contrast, immatures of Ae. aegypti were found in manmade containers in nearly 5% of nearby houses. These results demonstrate that bromeliads are not important producers of Ae. aegypti and Ae. albopictus and, hence, should not be a focus for dengue control. However, the results of this study of only one year in a single area may not represent outcomes in other urban localities where bromeliads, Ae. aegypti and dengue coincide in more disturbed habitats. PMID:20140379

  19. Bacteria as a source of oviposition attractant for Aedes aegypti mosquitoes.

    PubMed

    Arbaoui, A A; Chua, T H

    2014-03-01

    Since a safe and effective mass vaccination program against dengue fever is not presently available, a good way to prevent and control dengue outbreaks depends mainly on controlling the mosquito vectors. Aedes aegypti mosquito populations can be monitored and reduced by using ovitraps baited with organic infusions. A series of laboratory experiments were conducted which demonstrated that the bacteria in bamboo leaf infusion produce volatile attractants and contact chemical stimulants attractive to the female mosquitoes. The results showed that the female mosquitoes laid most of their eggs (59.9 ± 8.1 vs 2.9 ± 2.8 eggs, P<0.001) in bamboo leaf infusions when compared to distilled water. When the fresh infusion was filtered with a 0.45 μm filter membrane, the female mosquitoes laid significantly more eggs (64.1 ± 6.6 vs 4.9 ± 2.6 eggs, P<0.001) in unfiltered infusion. However when a 0.8 μm filter membrane was used, the female laid significantly more eggs (62.0 ± 4.3 vs 10.1 ± 7.8 eggs, P<0.001) in filtrate compared to a solution containing the residue. We also found that a mixture of bacteria isolated from bamboo leaf infusion serve as potent oviposition stimulants for gravid Aedes mosquitoes. Aedes aegypti laid significantly more eggs (63.3 ± 6.5 vs 3.1 ± 2.4 eggs, P<0.001) in bacteria suspension compared to sterile R2A medium. Our results suggest microbial activity has a role in the production of odorants that mediate the oviposition response of gravid mosquitoes. PMID:24862053

  20. Emerging tools for identification of arthropod vectors.

    PubMed

    Yssouf, Amina; Almeras, Lionel; Raoult, Didier; Parola, Philippe

    2016-04-01

    The rapid and reliable identification of arthropod vector species is an essential component of the fight against vector-borne diseases. However, owing to the lack of entomological expertise required for the morphological identification method, development of alternative and complementary tools is needed. This review describes the main methods used for arthropod identification, focusing on the emergence of protein profiling using MALDI-TOF MS technology. Sample preparation, analysis of reproducibility, database creation and blind tests for controlling accuracy of this tool for arthropod identification are described. The advantages and limitations of the MALDI-TOF MS method are illustrated by emphasizing different hematophagous arthropods, including mosquitoes and ticks, the top two main vectors of infectious diseases. PMID:27070074

  1. Mosquitoes and the Environment in Nile Delta Villages with Previous Rift Valley Fever Activity.

    PubMed

    Zayed, Abdelbaset B; Britch, Seth C; Soliman, Mohamed I; Linthicum, Kenneth J

    2015-06-01

    Egypt is affected by serious human and animal mosquito-borne diseases such as Rift Valley fever (RVF). We investigated how potential RVF virus mosquito vector populations are affected by environmental conditions in the Nile Delta region of Egypt by collecting mosquitoes and environmental data from 3 key governorates before and after 2012 seasonal flooding. We found that environmental effects varied among species, life stages, pre- and postflood groupings, and geographic populations of the same species, and that mosquito community composition could change after flooding. Our study provides preliminary data for modeling mosquitoes and mosquito-borne diseases in the Nile Delta region. PMID:26181689

  2. Old ingredients for a new recipe? Neem cake, a low-cost botanical by-product in the fight against mosquito-borne diseases.

    PubMed

    Benelli, Giovanni; Murugan, Kadarkarai; Panneerselvam, Chellasamy; Madhiyazhagan, Pari; Conti, Barbara; Nicoletti, Marcello

    2015-02-01

    Mosquitoes (Diptera: Culicidae) represent an important threat to millions of people worldwide, since they act as vectors for important pathogens, such as malaria, yellow fever, dengue and West Nile. Control programmes mainly rely on chemical treatments against larvae, indoor residual spraying and insecticide-treated bed nets. In recent years, huge efforts have been carried out to propose new eco-friendly alternatives, with a special focus on the evaluation of plant-borne mosquitocidal compounds. Major examples are neem-based products (Azadirachta indica A. Juss, Meliaceae) that have been proven as really effective against a huge range of pests of medical and veterinary importance, including mosquitoes. Recent research highlighted that neem cake, a cheap by-product from neem oil extraction, is an important source of mosquitocidal metabolites. In this review, we examined (i) the latest achievements about neem cake metabolomics with special reference to nor-terpenoid and related content; (ii) the neem cake ovicidal, larvicidal and pupicidal toxicity against Aedes, Anopheles and Culex mosquito vectors; (iii) its non-target effects against vertebrates; and (iv) its oviposition deterrence effects on mosquito females. Overall, neem cake can be proposed as an eco-friendly and low-cost source of chemicals to build newer and safer control tools against mosquito vectors. PMID:25563612

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

    PubMed

    Jeffries, Claire L; Walker, Thomas

    2015-01-01

    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 lines. The successful

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

    PubMed Central

    Jeffries, Claire L.; Walker, Thomas

    2015-01-01

    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 lines

  5. Toxicity of saponin isolated from Gymnema sylvestre R. Br. (Asclepiadaceae) against Culex tritaeniorhynchus Giles (Diptera: Culicidae) Japanese encephalitis vector mosquito in India.

    PubMed

    Elumalai, Kupppusamy; Dhanasekaran, Shanmugan; Krishnappa, Kaliamoorthy

    2012-12-01

    To determine the larvicidal activity of various extracts of Gymnema sylvestre against the Japanese Encephalitis vector, Culex tritaeniorynchus in Tamilnadu, India. To identify the active principle present in the promising fraction obtained in Chlorofom:Methanol extract of Fraction 2. The G. sylvestre leaf extracts were tested, employing WHO procedure against fourth instar larvae of C. tritaeniorhynchus and the larval mortalities were recorded at various concentrations (6.25, 12.5, 25.0, 50 and 100 µg/mL); the 24h LC50 values of the G. Sylvestre leaf extracts were determined following Probit analysis. It was noteworthy that treatment level 100 µg/mL exhibited highest mortality rates for the three different crude extracts and was significantly different from the mean mortalities recorded for the other concentrations. The LC50 values of 34.756 µg/mL (24.475-51.41), 31.351 µg/mL (20.634-47.043) and 28.577 µg/mL (25.159-32.308) were calculated for acetone, chloroform and methanol extract with the chi-square values of 10.301, 31.351 and 4.093 respectively. The present investigation proved that G. Sylvestre could be possibly utilized as an important component in the Vector Control Program. PMID:23152320

  6. Larvicidal Potential of the Halogenated Sesquiterpene (+)-Obtusol, Isolated from the Alga Laurencia dendroidea J. Agardh (Ceramiales: Rhodomelaceae), against the Dengue Vector Mosquito Aedes aegypti (Linnaeus) (Diptera: Culicidae).

    PubMed

    Salvador-Neto, Orlando; Gomes, Simone Azevedo; Soares, Angélica Ribeiro; Machado, Fernanda Lacerda da Silva; Samuels, Richard Ian; Nunes da Fonseca, Rodrigo; Souza-Menezes, Jackson; Moraes, Jorge Luiz da Cunha; Campos, Eldo; Mury, Flávia Borges; Silva, José Roberto

    2016-02-01

    Dengue is considered a serious public health problem in many tropical regions of the world including Brazil. At the moment, there is no viable alternative to reduce dengue infections other than controlling the insect vector, Aedes aegypti Linnaeus. In the continuing search for new sources of chemicals targeted at vector control, natural products are a promising alternative to synthetic pesticides. In our work, we investigated the toxicity of a bioactive compound extracted from the red alga Laurencia dendroidea J. Agardh. The initial results demonstrated that crude extracts, at a concentration of 5 ppm, caused pronounced mortality of second instar A. aegypti larvae. Two molecules, identified as (-)-elatol and (+)-obtusol were subsequently isolated from crude extract and further evaluated. Assays with (-)-elatol showed moderate larvicidal activity, whereas (+)-obtusol presented higher toxic activity than (-)-elatol, with a LC50 value of 3.5 ppm. Histological analysis of the larvae exposed to (+)-obtusol revealed damage to the intestinal epithelium. Moreover, (+)-obtusol-treated larvae incubated with 2 µM CM-H₂DCFDA showed the presence of reactive oxygen species, leading us to suggest that epithelial damage might be related to redox imbalance. These results demonstrate the potential of (+)-obtusol as a larvicide for use against A. aegypti and the possible mode of action of this compound. PMID:26821032

  7. Larvicidal Potential of the Halogenated Sesquiterpene (+)-Obtusol, Isolated from the Alga Laurencia dendroidea J. Agardh (Ceramiales: Rhodomelaceae), against the Dengue Vector Mosquito Aedes aegypti (Linnaeus) (Diptera: Culicidae)

    PubMed Central

    Salvador-Neto, Orlando; Gomes, Simone Azevedo; Soares, Angélica Ribeiro; Machado, Fernanda Lacerda da Silva; Samuels, Richard Ian; Nunes da Fonseca, Rodrigo; Souza-Menezes, Jackson; Moraes, Jorge Luiz da Cunha; Campos, Eldo; Mury, Flávia Borges; Silva, José Roberto

    2016-01-01

    Dengue is considered a serious public health problem in many tropical regions of the world including Brazil. At the moment, there is no viable alternative to reduce dengue infections other than controlling the insect vector, Aedes aegypti Linnaeus. In the continuing search for new sources of chemicals targeted at vector control, natural products are a promising alternative to synthetic pesticides. In our work, we investigated the toxicity of a bioactive compound extracted from the red alga Laurencia dendroidea J. Agardh. The initial results demonstrated that crude extracts, at a concentration of 5 ppm, caused pronounced mortality of second instar A. aegypti larvae. Two molecules, identified as (−)-elatol and (+)-obtusol were subsequently isolated from crude extract and further evaluated. Assays with (−)-elatol showed moderate larvicidal activity, whereas (+)-obtusol presented higher toxic activity than (−)-elatol, with a LC50 value of 3.5 ppm. Histological analysis of the larvae exposed to (+)-obtusol revealed damage to the intestinal epithelium. Moreover, (+)-obtusol-treated larvae incubated with 2 µM CM-H2DCFDA showed the presence of reactive oxygen species, leading us to suggest that epithelial damage might be related to redox imbalance. These results demonstrate the potential of (+)-obtusol as a larvicide for use against A. aegypti and the possible mode of action of this compound. PMID:26821032

  8. Plant based products: use and development as repellents against mosquitoes: A review.

    PubMed

    Rehman, Junaid U; Ali, Abbas; Khan, Ikhlas A

    2014-06-01

    Global warming and deforestation have resulted in the relocation of many living creatures including insects during the recent years. This has affected the population balance of disease vectors including mosquitoes resulting in outbreaks. Traditionally, mankind has been using plants as means of protection from the mosquitoes which are considered to be environment friendly unlike the synthetic chemicals that cause major risk to human health and the ecosystem. Researchers explored mainly, essential oils and traditional plants using different testing methodologies to find out repellent molecules effective against mosquitoes which is the main focus of this review. Among the promising plant species, Eucalyptus spp., Ocimum spp. and Cymbopogon spp. are the most cited. Data of repellency produced from the bioassay systems is difficult to quantify because of different parameters, testing system and standards of material used against mosquitoes. Mainly, the human forearm based bioassays have been used with different sizes of treatment area in the laboratory and the results have not been tested in the field conditions for residual activity. In addition, effectiveness of essential oils and their protection time can be increased by using vanillin as synergist and formulation techniques like microencapsulation and nanoemulsion. There is a need to develop an alternate in vitro bioassay system that can address the problems of uniformity of the results. PMID:24631763

  9. A Modified Experimental Hut Design for Studying Responses of Disease-Transmitting Mosquitoes to Indoor Interventions: The Ifakara Experimental Huts

    PubMed Central

    Okumu, Fredros O.; Moore, Jason; Mbeyela, Edgar; Sherlock, Mark; Sangusangu, Robert; Ligamba, Godfrey; Russell, Tanya; Moore, Sarah J.

    2012-01-01

    Differences between individual human houses can confound results of studies aimed at evaluating indoor vector control interventions such as insecticide treated nets (ITNs) and indoor residual insecticide spraying (IRS). Specially designed and standardised experimental huts have historically provided a solution to this challenge, with an added advantage that they can be fitted with special interception traps to sample entering or exiting mosquitoes. However, many of these experimental hut designs have a number of limitations, for example: 1) inability to sample mosquitoes on all sides of huts, 2) increased likelihood of live mosquitoes flying out of the huts, leaving mainly dead ones, 3) difficulties of cleaning the huts when a new insecticide is to be tested, and 4) the generally small size of the experimental huts, which can misrepresent actual local house sizes or airflow dynamics in the local houses. Here, we describe a modified experimental hut design - The Ifakara Experimental Huts- and explain how these huts can be used to more realistically monitor behavioural and physiological responses of wild, free-flying disease-transmitting mosquitoes, including the African malaria vectors of the species complexes Anopheles gambiae and Anopheles funestus, to indoor vector control-technologies including ITNs and IRS. Important characteristics of the Ifakara experimental huts include: 1) interception traps fitted onto eave spaces and windows, 2) use of eave baffles (panels that direct mosquito movement) to control exit of live mosquitoes through the eave spaces, 3) use of replaceable wall panels and ceilings, which allow safe insecticide disposal and reuse of the huts to test different insecticides in successive periods, 4) the kit format of the huts allowing portability and 5) an improved suite of entomological procedures to maximise data quality. PMID:22347415

  10. A modified experimental hut design for studying responses of disease-transmitting mosquitoes to indoor interventions: the Ifakara experimental huts.

    PubMed

    Okumu, Fredros O; Moore, Jason; Mbeyela, Edgar; Sherlock, Mark; Sangusangu, Robert; Ligamba, Godfrey; Russell, Tanya; Moore, Sarah J

    2012-01-01

    Differences between individual human houses can confound results of studies aimed at evaluating indoor vector control interventions such as insecticide treated nets (ITNs) and indoor residual insecticide spraying (IRS). Specially designed and standardised experimental huts have historically provided a solution to this challenge, with an added advantage that they can be fitted with special interception traps to sample entering or exiting mosquitoes. However, many of these experimental hut designs have a number of limitations, for example: 1) inability to sample mosquitoes on all sides of huts, 2) increased likelihood of live mosquitoes flying out of the huts, leaving mainly dead ones, 3) difficulties of cleaning the huts when a new insecticide is to be tested, and 4) the generally small size of the experimental huts, which can misrepresent actual local house sizes or airflow dynamics in the local houses. Here, we describe a modified experimental hut design - The Ifakara Experimental Huts- and explain how these huts can be used to more realistically monitor behavioural and physiological responses of wild, free-flying disease-transmitting mosquitoes, including the African malaria vectors of the species complexes Anopheles gambiae and Anopheles funestus, to indoor vector control-technologies including ITNs and IRS. Important characteristics of the Ifakara experimental huts include: 1) interception traps fitted onto eave spaces and windows, 2) use of eave baffles (panels that direct mosquito movement) to control exit of live mosquitoes through the eave spaces, 3) use of replaceable wall panels and ceilings, which allow safe insecticide disposal and reuse of the huts to test different insecticides in successive periods, 4) the kit format of the huts allowing portability and 5) an improved suite of entomological procedures to maximise data quality. PMID:22347415

  11. Recombinant bacteria for mosquito control.

    PubMed

    Federici, B A; Park, H-W; Bideshi, D K; Wirth, M C; Johnson, J J

    2003-11-01

    Bacterial insecticides have been used for the control of nuisance and vector mosquitoes for more than two decades. Nevertheless, due primarily to their high cost and often only moderate efficacy, these insecticides remain of limited use in tropical countries where mosquito-borne diseases are prevalent. Recently, however, recombinant DNA techniques have been used to improve bacterial insecticide efficacy by markedly increasing the synthesis of mosquitocidal proteins and by enabling new endotoxin combinations from different bacteria to be produced within single strains. These new strains combine mosquitocidal Cry and Cyt proteins of Bacillus thuringiensis with the binary toxin of Bacillus sphaericus, improving efficacy against Culex species by 10-fold and greatly reducing the potential for resistance through the presence of Cyt1A. Moreover, although intensive use of B. sphaericus against Culex populations in the field can result in high levels of resistance, most of this can be suppressed by combining this bacterial species with Cyt1A; the latter enables the binary toxin of this species to enter midgut epithelial cells via the microvillar membrane in the absence of a midgut receptor. The availability of these novel strains and newly discovered mosquitocidal proteins, such as the Mtx toxins of B. sphaericus, offers the potential for constructing a range of recombinant bacterial insecticides for more effective control of the mosquito vectors of filariasis, Dengue fever and malaria. PMID:14506223

  12. Mosquito, Bird and Human Surveillance of West Nile and Usutu Viruses in Emilia-Romagna Region (Italy) in 2010

    PubMed Central

    Calzolari, Mattia; Gaibani, Paolo; Bellini, Romeo; Defilippo, Francesco; Pierro, Anna; Albieri, Alessandro; Maioli, Giulia; Luppi, Andrea; Rossini, Giada; Balzani, Agnese; Tamba, Marco; Galletti, Giorgio; Gelati, Antonio; Carrieri, Marco; Poglayen, Giovanni; Cavrini, Francesca; Natalini, Silvano; Dottori, Michele; Sambri, Vittorio; Angelini, Paola; Bonilauri, Paolo

    2012-01-01

    Background In 2008, after the first West Nile virus (WNV) detection in the Emilia-Romagna region, a surveillance system, including mosquito- and bird-based surveillance, was established to evaluate the virus presence. Surveillance was improved in following years by extending the monitoring to larger areas and increasing the numbers of mosquitoes and birds tested. Methodology/Principal Findings A network of mosquito traps, evenly distributed and regularly activated, was set up within the surveyed area. A total of 438,558 mosquitoes, grouped in 3,111 pools and 1,276 birds (1,130 actively sampled and 146 from passive surveillance), were tested by biomolecular analysis. The survey detected WNV in 3 Culex pipiens pools while Usutu virus (USUV) was found in 89 Cx. pipiens pools and in 2 Aedes albopictus pools. Two birds were WNV-positive and 12 were USUV-positive. Furthermore, 30 human cases of acute meningoencephalitis, possibly caused by WNV or USUV, were evaluated for both viruses and 1,053 blood bags were tested for WNV, without any positive result. Conclusions/Significance Despite not finding symptomatic human WNV infections during 2010, the persistence of the virus, probably due to overwintering, was confirmed through viral circulation in mosquitoes and birds, as well as for USUV. In 2010, circulation of the two viruses was lower and more delayed than in 2009, but this decrease was not explained by the relative abundance of Cx. pipiens mosquito, which was greater in 2010. The USUV detection in mosquito species confirms the role of Cx. pipiens as the main vector and the possible involvement of Ae. albopictus in the virus cycle. The effects of meteorological conditions on the presence of USUV-positive mosquito pools were considered finding an association with drought conditions and a wide temperature range. The output produced by the surveillance system demonstrated its usefulness and reliability in terms of planning public health policies. PMID:22666446

  13. Disruption of dengue virus transmission by mosquitoes

    PubMed Central

    Franz, Alexander W.E.; Balaraman, Velmurugan; Fraser, Malcolm J.

    2015-01-01

    Current control efforts for mosquito-borne arboviruses focus on mosquito control involving insecticide applications, which are becoming increasingly ineffective and unsustainable in urban areas. Mosquito population replacement is an alternative arbovirus control concept aiming at replacing virus-competent vector populations with laboratory-engineered incompetent vectors. A prerequisite for this strategy is the design of robust anti-pathogen effectors that can ultimately be genetically driven through a wild-type population. Several anti-pathogen effector concepts have been developed that target the RNA genomes of arboviruses such as dengue virus in a highly sequence-specific manner. Design principles are based on long inverted-repeat RNA triggered RNA interference, catalytic hammerhead ribozymes, and trans-splicing Group I Introns that are able to induce apoptosis in virus-infected cells following splicing with target viral RNA. PMID:26120563

  14. Symbiotic control of mosquito borne disease.

    PubMed

    Ricci, Irene; Valzano, Matteo; Ulissi, Ulisse; Epis, Sara; Cappelli, Alessia; Favia, Guido

    2012-11-01

    It is well accepted that the symbiotic relationships insects have established with several microorganisms have had a key role in their evolutionary success. Bacterial symbiosis is also prevalent in insects that are efficient disease vectors, and numerous studies have sought to decrypt the basic mechanisms of the host-symbiont relationships and develop ways to control vector borne diseases. 'Symbiotic control', a new multifaceted approach that uses symbiotic microorganisms to control insect pests or reduce vector competence, seems particularly promising. Three such approaches currently at the cutting edge are: (1) the disruption of microbial symbionts required by insect pests; (2) the manipulation of symbionts that can express anti-pathogen molecules within the host; and (3) the introduction of endogenous microbes that affect life-span and vector capacity of the new hosts in insect populations. This work reviews current knowledge on microbial symbiosis in mosquitoes that holds promise for development of symbiotic control for mosquito borne diseases. PMID:23265608

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

    PubMed Central

    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 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 mosquito control tool

  16. In silico models for predicting vector control chemicals targeting Aedes aegypti

    PubMed Central

    Devillers, J.; Lagneau, C.; Lattes, A.; Garrigues, J.C.; Clémenté, M.M.; Yébakima, A.

    2014-01-01

    Human arboviral diseases have emerged or re-emerged in numerous countries worldwide due to a number of factors including the lack of progress in vaccine development, lack of drugs, insecticide resistance in mosquitoes, climate changes, societal behaviours, and economical constraints. Thus, Aedes aegypti is the main vector of the yellow fever and dengue fever flaviviruses and is also responsible for several recent outbreaks of the chikungunya alphavirus. As for the other mosquito species, the A. aegypti control relies heavily on the use of insecticides. However, because of increasing resistance to the different families of insecticides, reduction of Aedes populations is becoming increasingly difficult. Despite the unquestionable utility of insecticides in fighting mosquito populations, there are very few new insecticides developed and commercialized for vector control. This is because the high cost of the discovery of an insecticide is not counterbalanced by the ‘low profitability’ of the vector control market. Fortunately, the use of quantitative structure–activity relationship (QSAR) modelling allows the reduction of time and cost in the discovery of new chemical structures potentially active against mosquitoes. In this context, the goal of the present study was to review all the existing QSAR models on A. aegypti. The homology and pharmacophore models were also reviewed. Specific attention was paid to show the variety of targets investigated in Aedes in relation to the physiology and ecology of the mosquito as well as the diversity of the chemical structures which have been proposed, encompassing man-made and natural substances. PMID:25275884

  17. Seasonal and habitat effects on dengue and West Nile virus vectors in San Juan, Puerto Rico.

    PubMed

    Smith, Joshua; Amador, Manuel; Barrera, Roberto

    2009-03-01

    The presence of West Nile (WNV) and dengue viruses and the lack of recent mosquito surveys in Puerto Rico prompted an investigation on the distribution and abundance of potential arbovirus vectors in the San Juan Metropolitan Area, and their variation with seasons and habitats. We sampled mosquitoes in early and late 2005 in 58 sites from forests, nonforest vegetation, wetlands, and high- and low-density housing areas using ovijars, Centers for Disease Control and Prevention miniature light/CO2 traps, and gravid traps. A total of 28 mosquito species was found. San Juan had potential WNV enzooticvectors (Culex nigripalpus) within and around the city in wetlands and forests, but few were captured in residential areas. A potential WNV bridge vector (Cx. quinquefasciatus) was abundant in urbanized areas, and it was positively correlated with the main dengue vector, Aedes aegypti. High-density housing areas harbored more Ae. aegypti. Container mosquitoes, including Aedes mediovittatus, were more abundant during the climax of the rainy season when most dengue occurs in Puerto Rico. The greatest risk for contracting WNV would be visiting forests and swamps at night. Culex (Culex) and Culex (Melanoconion) mosquito species were more abundant during the transition dry-wet seasons (March-May). PMID:19432067

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

    PubMed

    Yamamoto, Daisuke S; Sumitani, Megumi; Kasashima, Katsumi; Sezutsu, Hideki; Matsuoka, Hiroyuki

    2016-09-01

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

  19. Bacterial associations reveal spatial population dynamics in Anopheles gambiae mosquitoes.

    PubMed

    Buck, Moritz; Nilsson, Louise K J; Brunius, Carl; Dabiré, Roch K; Hopkins, Richard; Terenius, Olle

    2016-01-01

    The intolerable burden of malaria has for too long plagued humanity and the prospect of eradicating malaria is an optimistic, but reachable, target in the 21(st) century. However, extensive knowledge is needed about the spatial structure of mosquito populations in order to develop effective interventions against malaria transmission. We hypothesized that the microbiota associated with a mosquito reflects acquisition of bacteria in different environments. By analyzing the whole-body bacterial flora of An. gambiae mosquitoes from Burkina Faso by 16 S amplicon sequencing, we found that the different environments gave each mosquito a specific bacterial profile. In addition, the bacterial profiles provided precise and predicting information on the spatial dynamics of the mosquito population as a whole and showed that the mosquitoes formed clear local populations within a meta-population network. We believe that using microbiotas as proxies for population structures will greatly aid improving the performance of vector interventions around the world. PMID:26960555

  20. Bacterial associations reveal spatial population dynamics in Anopheles gambiae mosquitoes

    PubMed Central

    Buck, Moritz; Nilsson, Louise K. J.; Brunius, Carl; Dabiré, Roch K.; Hopkins, Richard; Terenius, Olle

    2016-01-01

    The intolerable burden of malaria has for too long plagued humanity and the prospect of eradicating malaria is an optimistic, but reachable, target in the 21st century. However, extensive knowledge is needed about the spatial structure of mosquito populations in order to develop effective interventions against malaria transmission. We hypothesized that the microbiota associated with a mosquito reflects acquisition of bacteria in different environments. By analyzing the whole-body bacterial flora of An. gambiae mosquitoes from Burkina Faso by 16 S amplicon sequencing, we found that the different environments gave each mosquito a specific bacterial profile. In addition, the bacterial profiles provided precise and predicting information on the spatial dynamics of the mosquito population as a whole and showed that the mosquitoes formed clear local populations within a meta-population network. We believe that using microbiotas as proxies for population structures will greatly aid improving the performance of vector interventions around the world. PMID:26960555

  1. Natural malaria infection reduces starvation resistance of nutritionally stressed mosquitoes.

    PubMed

    Lalubin, Fabrice; Delédevant, Aline; Glaizot, Olivier; Christe, Philippe

    2014-07-01

    In disease ecology, there is growing evidence that environmental quality interacts with parasite and host to determine host susceptibility to an infection. Most studies of malaria parasites have focused on the infection costs incurred by the hosts, and few have investigated the costs on mosquito vectors. The interplay between the environment, the vector and the parasite has therefore mostly been ignored and often relied on unnatural or allopatric Plasmodium/vector associations. Here, we investigated the effects of natural avian malaria infection on both fecundity and survival of field-caught female Culex pipiens mosquitoes, individually maintained in laboratory conditions. We manipulated environmental quality by providing mosquitoes with different concentrations of glucose-feeding solution prior to submitting them to a starvation challenge. We used molecular-based methods to assess mosquitoes' infection status. We found that mosquitoes infected with Plasmodium had lower starvation resistance than uninfected ones only under low nutritional conditions. The effect of nutritional stress varied with time, with the difference of starvation resistance between optimally and suboptimally fed mosquitoes increasing from spring to summer, as shown by a significant interaction between diet treatment and months of capture. Infected and uninfected mosquitoes had similar clutch size, indicating no effect of infection on fecundity. Overall, this study suggests that avian malaria vectors may suffer Plasmodium infection costs in their natural habitat, under certain environmental conditions. This may have major implications for disease transmission in the wild. PMID:24286465

  2. Predicting the risk of an endemic focus of Leishmania tropica becoming established in South-Western Europe through the presence of its main vector, Phlebotomus sergenti Parrot, 1917.

    PubMed

    Barón, S D; Morillas-Márquez, F; Morales-Yuste, M; Díaz-Sáez, V; Gállego, M; Molina, R; Martín-Sánchez, J

    2013-09-01

    The aim of the study was the construction of risk maps for exposure to Phlebotomus sergenti, the main vector of Leishmania tropica, with a view to identifying hot spots for the potential establishment of this parasite in the southwest of Europe. Data were collected on the presence/absence of this vector and the ecological and climatic characteristics of 662 sampling sites located in the southeast, centre and northeast of the Iberian Peninsula (south-western Europe). The environmental factors associated with the distribution of P. sergenti were determined. The best predictors for the presence of this dipteran were ‘altitude’, ‘land use’, ‘land surface temperature’, ‘aspect’, ‘adjacent land cover’, ‘absence of vegetation in wall’ and the ‘absence of PVC pipes in the drainage holes of retaining walls’. Risk maps for exposure to the vector were drawn up based on these variables. The validation of the predictive risk model confirmed its usefulness in the detection of areas with a high risk of P. sergenti being present. These locations represent potential hot spots for an autochthonous focus of L. tropica becoming established. The risk maps produced for P. sergenti presence revealed several areas in the centre and south of the Iberian Peninsula to be the most prone to this process, which would make it possible for the disease to enter south-western Europe. PMID:23965821

  3. Mosquito, egg raft (image)

    MedlinePlus

    Mosquitoes of the Culex species lay their eggs in the form of egg rafts that float in ... feed on micro-organisms before developing into flying mosquitoes. (Image courtesy of the Centers for Disease Control ...

  4. Mosquito, adult (image)

    MedlinePlus

    This illustration shows an adult southern house mosquito. This mosquito feeds on blood and is the carrier of many diseases, such as encephalitis, West Nile, dengue fever, yellow fever, and others. ( ...

  5. Structure and Function of a G-actin Sequestering Protein with a Vital Role in Malaria Oocyst Development inside the Mosquito Vector*

    PubMed Central

    Hliscs, Marion; Sattler, Julia M.; Tempel, Wolfram; Artz, Jennifer D.; Dong, Aiping; Hui, Raymond; Matuschewski, Kai; Schüler, Herwig

    2010-01-01

    Cyclase-associated proteins (CAPs) are evolutionary conserved G-actin-binding proteins that regulate microfilament turnover. CAPs have a modular structure consisting of an N-terminal adenylate cyclase binding domain, a central proline-rich segment, and a C-terminal actin binding domain. Protozoan parasites of the phylum Apicomplexa, such as Cryptosporidium and the malaria parasite Plasmodium, express small CAP orthologs with homology to the C-terminal actin binding domain (C-CAP). Here, we demonstrate by reverse genetics that C-CAP is dispensable for the pathogenic Plasmodium blood stages. However, c-cap(-) parasites display a complete defect in oocyst development in the insect vector. By trans-species complementation we show that the Cryptosporidium parvum ortholog complements the Plasmodium gene functions. Purified recombinant C. parvum C-CAP protein binds actin monomers and prevents actin polymerization. The crystal structure of C. parvum C-CAP shows two monomers with a right-handed β-helical fold intercalated at their C termini to form the putative physiological dimer. Our results reveal a specific vital role for an apicomplexan G-actin-binding protein during sporogony, the parasite replication phase that precedes formation of malaria transmission stages. This study also exemplifies how Plasmodium reverse genetics combined with biochemical and structural analyses of orthologous proteins can offer a fast track toward systematic gene characterization in apicomplexan parasites. PMID:20083609

  6. Amazonian malaria: Asymptomatic human reservoirs, diagnostic challenges, environmentally-driven changes in mosquito vector populations, and the mandate for sustainable control strategies

    PubMed Central

    da Silva-Nunes, Mônica; Moreno, Marta; Conn, Jan E.; Gamboa, Dionicia; Abeles, Shira; Vinetz, Joseph M.; Ferreira, Marcelo U.

    2012-01-01

    Across the Americas and the Caribbean, nearly 561,000 slide-confirmed malaria infections were reported officially in 2008. The nine Amazonian countries accounted for 89% of these infections; Brazil and Peru alone contributed 56% and 7% of them, respectively. Local populations of the relatively neglected parasite P. vivax, which currently accounts for 77% of the regional malaria burden, are extremely diverse genetically and geographically structured. At a time when malaria elimination is placed on the public health agenda of several endemic countries, it remains unclear why malaria proved so difficult to control in areas of relatively low levels of transmission such as the Amazon Basin. We hypothesize that asymptomatic parasite carriage and massive environmental changes that affect vector abundance and behavior are major contributors to malaria transmission in epidemiologically diverse areas across the Amazon Basin. Here we review available data supporting this hypothesis and discuss their implications for current and future malaria intervention policies in the region. Given that locally generated scientific evidence is urgently required to support malaria control interventions in Amazonia, we briefly describe the aims of our current field-oriented malaria research in rural villages and gold-mining enclaves in Peru and a recently opened agricultural settlement in Brazil. PMID:22015425

  7. Use of geographic information systems to depict and analyze mosquito population trends.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mosquitoes transmit (vector) disease agents that cause malaria, yellow fever, dengue, West Nile fever, and encephalitis. Spread of these diseases is controlled by the management of mosquito population levels, changes in which are monitored in vector surveillance programs by the use of mechanical tr...

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

    PubMed Central

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

    2014-01-01

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

  9. MAN, MOSQUITOES AND MICROBES.

    ERIC Educational Resources Information Center

    SCHOONOVER, ROBERT A.

    THE CONTROL OF MOSQUITOES IS A MATTER OF INCREASING CONCERN IN THE STATE OF FLORIDA. A BRIEF DESCRIPTION OF THE LIFE CYCLE, VARIOUS SPECIES, CONTROL, AND DESCRIPTION OF DISEASES TRANSMITTED BY THE MOSQUITO WAS PRESENTED. THE ARTICLE CONCLUDED THAT MOSQUITO CONTROL IS NOT ONLY A HEALTH PROBLEM, BUT ALSO A MATTER OF IMPROVED ECONOMICS IN RELATION TO…

  10. Mosquito management: Ecological approaches

    NASA Astrophysics Data System (ADS)

    Garcia, R.

    1983-01-01

    This article discusses organism use for management of mosquitoes included are considerations of the introduction and/or manipulation of plants, animals, and microorganisms into breeding habitats in which they act to make conditions less suitable for mosquito production. The importance of foresight and careful planning is stressed with regard to developing mosquito management strategies

  11. Phylogeography and Genetic Variation of Triatoma dimidiata, the Main Chagas Disease Vector in Central America, and Its Position within the Genus Triatoma

    PubMed Central

    Bargues, María Dolores; Klisiowicz, Debora R.; Gonzalez-Candelas, Fernando; Ramsey, Janine M.; Monroy, Carlota; Ponce, Carlos; Salazar-Schettino, Paz María; Panzera, Francisco; Abad-Franch, Fernando; Sousa, Octavio E.; Schofield, Christopher J.; Dujardin, Jean Pierre; Guhl, Felipe; Mas-Coma, Santiago

    2008-01-01

    Background Among Chagas disease triatomine vectors, the largest genus, Triatoma, includes species of high public health interest. Triatoma dimidiata, the main vector throughout Central America and up to Ecuador, presents extensive phenotypic, genotypic, and behavioral diversity in sylvatic, peridomestic and domestic habitats, and non-domiciliated populations acting as reinfestation sources. DNA sequence analyses, phylogenetic reconstruction methods, and genetic variation approaches are combined to investigate the haplotype profiling, genetic polymorphism, phylogeography, and evolutionary trends of T. dimidiata and its closest relatives within Triatoma. This is the largest interpopulational analysis performed on a triatomine species so far. Methodology and Findings Triatomines from Mexico, Guatemala, Honduras, Nicaragua, Panama, Cuba, Colombia, Ecuador, and Brazil were used. Triatoma dimidiata populations follow different evolutionary divergences in which geographical isolation appears to have had an important influence. A southern Mexican–northern Guatemalan ancestral form gave rise to two main clades. One clade remained confined to the Yucatan peninsula and northern parts of Chiapas State, Guatemala, and Honduras, with extant descendants deserving specific status. Within the second clade, extant subspecies diversity was shaped by adaptive radiation derived from Guatemalan ancestral populations. Central American populations correspond to subspecies T. d. dimidiata. A southern spread into Panama and Colombia gave the T. d. capitata forms, and a northwestern spread rising from Guatemala into Mexico gave the T. d. maculipennis forms. Triatoma hegneri appears as a subspecific insular form. Conclusions The comparison with very numerous Triatoma species allows us to reach highly supported conclusions not only about T. dimidiata, but also on different, important Triatoma species groupings and their evolution. The very large intraspecific genetic variability found in T

  12. Pteridine fluorescence for age determination of Anopheles mosquitoes.

    PubMed

    Wu, D; Lehane, M J

    1999-02-01

    The age structure of mosquito populations is of great relevance to understanding the dynamics of disease transmission and in monitoring the success of control operations. Unfortunately, the ovarian dissection methods currently available for determining the age of adult mosquitoes are technically difficult, slow and may be of limited value, because the proportion of diagnostic ovarioles in the ovary declines with age. By means of reversed-phase HPLC this study investigated the malaria vectors Anopheles gambiae and An. stephensi to see if changes in fluorescent pteridine pigments, which have been used in other insects to determine the age of field-caught individuals, may be useful for age determination in mosquitoes. Whole body fluorescence was inversely proportional to age (P < 0.001, r2 > 91%) up to 30 days postemergence, with the regression values: y = 40580-706x for An. gambiae, and y = 52896-681x for An. stephensi. In both species the main pteridines were 6-biopterin, pterin-6-carboxylic acid and an unidentified fluorescent compound. An. gambiae had only 50-70% as much fluorescence as An. stephensi, and fluorescent compounds were relatively more concentrated in the head than in the thorax (ratios 1:0.8 An. gambiae; 1:0.5 An. stephensi). The results of this laboratory study are encouraging. It seems feasible that this simpler and faster technique of fluorescence quantification could yield results of equivalent accuracy to the interpretation of ovarian dissection. A double-blind field trial comparing the accuracy of this technique to marked, released and recaptured mosquitoes is required to test the usefulness of the pteridine method in the field. PMID:10194749

  13. Effects of fipronil on dogs over Triatoma infestans, the main vector of Trypanosoma cruzi, causative agent of Chagas disease.

    PubMed

    Amelotti, Ivana; Catalá, Silvia S; Gorla, David E

    2012-10-01

    Chagas disease is the most important endemic disease in Latin America, mainly transmitted by Triatoma infestans in the Southern Cone countries of South America. Dogs are one of the main domestic reservoirs of Trypanosoma cruzi, the etiological agent of Chagas disease. The presence of dogs in rural households of endemic areas significantly increases the likelihood of the vectorial transmission of the parasite. We studied the mortality and blood intake of T. infestans exposed to dogs treated with different doses and formulations of fipronil. Two doses, two formulations, and different distances to the application point of fipronil were compared. Third instar nymphs of T. infestans were fed at different time intervals after the insecticide application up to 45 days post-application. No significant difference was found between the blood intake of nymphs fed on control and treated dogs with different doses and formulations (p > 0.05). The spray formulation showed lower effect and persistence than the spot-on formulation. The mortality rate caused by the spot-on formulation in the 26.8-mg active ingredient (a.i.)/kg dose was higher (48%) than with the 13.4-mg a.i./kg dose (25%), 24 h after the insecticide application. The effect was highly heterogeneous among replicates of the same treatment. The mortality rate of nymphs fed over the point of the insecticide application was higher than the mortality of nymphs fed over places 12 cm apart from the fipronil application point, suggesting that the distribution of fipronil over the dog body is lower than the needed one to obtain a persistent triatomicide effect. PMID:22669692

  14. Effects of Local Anthropogenic Changes on Potential Malaria Vector Anopheles hyrcanus and West Nile Virus Vector Culex modestus, Camargue, France

    PubMed Central

    Ponçon, Nicolas; Balenghien, Thomas; Toty, Céline; Ferré, Jean Baptiste; Thomas, Cyrille; Dervieux, Alain; L’Ambert, Grégory; Schaffner, Francis; Bardin, Olivier

    2007-01-01

    Using historical data, we highlight the consequences of anthropogenic ecosystem modifications on the abundance of mosquitoes implicated as the current most important potential malaria vector, Anopheles hyrcanus, and the most important West Nile virus (WNV) vector, Culex modestus, in the Camargue region, France. From World War II to 1971, populations of these species increased as rice cultivation expanded in the region in a political context that supported agriculture. They then fell, likely because of decreased cultivation and increased pesticide use to control a rice pest. The species increased again after 2000 with the advent of more targeted pest-management strategies, mainly the results of European regulations decisions. An intertwined influence of political context, environmental constraints, technical improvements, and social factors led to changes in mosquito abundance that had potential consequences on malaria and WNV transmission. These findings suggest that anthropogenic changes should not be underestimated in vectorborne disease recrudescence. PMID:18258028

  15. Genetic control of mosquitoes: population suppression strategies.

    PubMed

    Wilke, André Barretto Bruno; Marrelli, Mauro Toledo

    2012-01-01

    Over the last two decades, morbidity and mortality from malaria and dengue fever among other pathogens are an increasing Public Health problem. The increase in the geographic distribution of vectors is accompanied by the emergence of viruses and diseases in new areas. There are insufficient specific therapeutic drugs available and there are no reliable vaccines for malaria or dengue, although some progress has been achieved, there is still a long way between its development and actual field use. Most mosquito control measures have failed to achieve their goals, mostly because of the mosquito's great reproductive capacity and genomic flexibility. Chemical control is increasingly restricted due to potential human toxicity, mortality in no target organisms, insecticide resistance, and other environmental impacts. Other strategies for mosquito control are desperately needed. The Sterile Insect Technique (SIT) is a species-specific and environmentally benign method for insect population suppression, it is based on mass rearing, radiation mediated sterilization, and release of a large number of male insects. Releasing of Insects carrying a dominant lethal gene (RIDL) offers a solution to many of the drawbacks of traditional SIT that have limited its application in mosquitoes while maintaining its environmentally friendly and species-specific utility. The self-limiting nature of sterile mosquitoes tends to make the issues related to field use of these somewhat less challenging than for self-spreading systems characteristic of population replacement strategies. They also are closer to field use, so might be appropriate to consider first. The prospect of genetic control methods against mosquito vectored human diseases is rapidly becoming a reality, many decisions will need to be made on a national, regional and international level regarding the biosafety, social, cultural and ethical aspects of the use and deployment of these vector control methods. PMID:22983293

  16. Analysing the generality of spatially predictive mosquito habitat models

    PubMed Central

    Li, Li; Bian, Ling; Yakob, Laith; Zhou, Guofa; Yan, Guiyun

    2013-01-01

    The increasing spread of multi-drug resistant malaria in African highlands has highlighted the importance of malaria suppression through vector control. Its historical success has meant that larval control has been proposed as part of an integrated malaria vector control program. Due to high operation costs, larval control activities would benefit greatly if the locations of mosquito habitats could be identified quickly and easily, allowing for focal habitat source suppression. Several mosquito habitat models have been developed to predict the location of mosquito habitats. However, to what extent these models can be generalised across time and space to predict the distribution of dynamic mosquito habitats remains largely unexplored. This study used mosquito habitat data collected in six different time periods and four different modelling approaches to establish 24 mosquito habitat models. We systematically tested the generality of these 24 mosquito habitat models. We found that although habitat–environment relationships change temporally, a modest level of performance was attained when validating the models using data collected from different time periods. We also describe flexible approaches to the predictive modelling of mosquito habitats, that provide novel modelling architecture for future research efforts. PMID:21527240

  17. Tissue Barriers to Arbovirus Infection in Mosquitoes

    PubMed Central

    Franz, Alexander W.E.; Kantor, Asher M.; Passarelli, A. Lorena; Clem, Rollie J.

    2015-01-01

    Arthropod-borne viruses (arboviruses) circulate in nature between arthropod vectors and vertebrate hosts. Arboviruses often cause devastating diseases in vertebrate hosts, but they typically do not cause significant pathology in their arthropod vectors. Following oral acquisition of a viremic bloodmeal from a vertebrate host, the arbovirus disease cycle requires replication in the cellular environment of the arthropod vector. Once the vector has become systemically and persistently infected, the vector is able to transmit the virus to an uninfected vertebrate host. In order to systemically infect the vector, the virus must cope with innate immune responses and overcome several tissue barriers associated with the midgut and the salivary glands. In this review we describe, in detail, the typical arbovirus infection route in competent mosquito vectors. Based on what is known from the literature, we explain the nature of the tissue barriers that arboviruses are confronted with in a mosquito vector and how arboviruses might surmount these barriers. We also point out controversial findings to highlight particular areas that are not well understood and require further research efforts. PMID:26184281

  18. Tissue Barriers to Arbovirus Infection in Mosquitoes.

    PubMed

    Franz, Alexander W E; Kantor, Asher M; Passarelli, A Lorena; Clem, Rollie J

    2015-07-01

    Arthropod-borne viruses (arboviruses) circulate in nature between arthropod vectors and vertebrate hosts. Arboviruses often cause devastating diseases in vertebrate hosts, but they typically do not cause significant pathology in their arthropod vectors. Following oral acquisition of a viremic bloodmeal from a vertebrate host, the arbovirus disease cycle requires replication in the cellular environment of the arthropod vector. Once the vector has become systemically and persistently infected, the vector is able to transmit the virus to an uninfected vertebrate host. In order to systemically infect the vector, the virus must cope with innate immune responses and overcome several tissue barriers associated with the midgut and the salivary glands. In this review we describe, in detail, the typical arbovirus infection route in competent mosquito vectors. Based on what is known from the literature, we explain the nature of the tissue barriers that arboviruses are confronted with in a mosquito vector and how arboviruses might surmount these barriers. We also point out controversial findings to highlight particular areas that are not well understood and require further research efforts. PMID:26184281

  19. Malaria Mosquitoes Attracted by Fatal Fungus

    PubMed Central

    George, Justin; Jenkins, Nina E.; Blanford, Simon; Thomas, Matthew B.; Baker, Thomas C.

    2013-01-01

    Insect-killing fungi such as Beauveria bassiana are being evaluated as possible active ingredients for use in novel biopesticides against mosquito vectors that transmit malaria. Fungal pathogens infect through contact and so applications of spores to surfaces such as walls, nets, or other resting sites provide possible routes to infect mosquitoes in and around domestic dwellings. However, some insects can detect and actively avoid fungal spores to reduce infection risk. If true for mosquitoes, such behavior could render the biopesticide approach ineffective. Here we find that the spores of B. bassiana are highly attractive to females of Anopheles stephensi, a major anopheline mosquito vector of human malaria in Asia. We further find that An. stephensi females are preferentially attracted to dead and dying caterpillars infected with B. bassiana, landing on them and subsequently becoming infected with the fungus. Females are also preferentially attracted to cloth sprayed with oil-formulated B. bassiana spores, with 95% of the attracted females becoming infected after a one-minute visit on the cloth. This is the first report of an insect being attracted to a lethal fungal pathogen. The exact mechanisms involved in this behavior remain unclear. Nonetheless, our results indicate that biopesticidal formulations comprising B. bassiana spores will be conducive to attraction and on-source visitation by malaria vectors. PMID:23658757

  20. Malaria mosquitoes attracted by fatal fungus.

    PubMed

    George, Justin; Jenkins, Nina E; Blanford, Simon; Thomas, Matthew B; Baker, Thomas C

    2013-01-01

    Insect-killing fungi such as Beauveria bassiana are being evaluated as possible active ingredients for use in novel biopesticides against mosquito vectors that transmit malaria. Fungal pathogens infect through contact and so applications of spores to surfaces such as walls, nets, or other resting sites provide possible routes to infect mosquitoes in and around domestic dwellings. However, some insects can detect and actively avoid fungal spores to reduce infection risk. If true for mosquitoes, such behavior could render the biopesticide approach ineffective. Here we find that the spores of B. bassiana are highly attractive to females of Anopheles stephensi, a major anopheline mosquito vector of human malaria in Asia. We further find that An. stephensi females are preferentially attracted to dead and dying caterpillars infected with B. bassiana, landing on them and subsequently becoming infected with the fungus. Females are also preferentially attracted to cloth sprayed with oil-formulated B. bassiana spores, with 95% of the attracted females becoming infected after a one-minute visit on the cloth. This is the first report of an insect being attracted to a lethal fungal pathogen. The exact mechanisms involved in this behavior remain unclear. Nonetheless, our results indicate that biopesticidal formulations comprising B. bassiana spores will be conducive to attraction and on-source visitation by malaria vectors. PMID:23658757

  1. Anopheles darlingi (Diptera: Culicidae) Dynamics in Relation to Meteorological Data in a Cattle Farm Located in the Coastal Region of French Guiana: Advantage of Mosquito Magnet Trap.

    PubMed

    Vezenegho, Samuel B; Carinci, Romuald; Gaborit, Pascal; Issaly, Jean; Dusfour, Isabelle; Briolant, Sebastien; Girod, Romain

    2015-06-01

    Information on dynamics of anopheline mosquitoes is limited in the coastal zone of French Guiana compared with inland endemic areas. Importantly, improvement of surveillance techniques for assessing malaria transmission indicators and comprehension of impact of meteorological factors on Anopheles darlingi Root, the main malaria vector, are necessary. Anopheline mosquitoes were collected continuously during 2012 and 2013 using Mosquito Magnet traps baited with octenol and human landing catches. The two methods were compared based on trends in abundance and parity rate of An. darlingi. Impact of meteorological factors on An. darlingi density estimates was investigated using Spearman's correlation and by binomial negative regression analysis. In all, 11,928 anopheline mosquitoes were collected, and 90.7% (n = 10,815) were identified consisting of four species, with An. darlingi making up 94.9% (n = 10,264). An. darlingi specimens collected by the two methods were significantly correlated, and no difference in parity rate was observed. The abundance of this species peaked in September (dry season) and variations along the years were influenced by relative humidity, temperature, rainfall, and wind speed. Number of mosquitoes collected during peak aggression period was influenced by wind speed and rainfall. Data gathered in this study provide fundamental information about An. darlingi, which can facilitate the design of vector control strategies and construction of models for predicting malaria risk. PMID:26313950

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

    PubMed Central

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

    2015-01-01

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

  3. A novel in vitro bioassay to explore the repellent effects of compounds against mosquito Aedes Aegypti (Diptera: Culicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mosquitoes are vectors for many pathogens that can cause human diseases which can result in high rates of human morbidity and mortality at significant levels of transmission. Repellents play an important role in reducing mosquito bites and hence the risk of spread of mosquito borne diseases. Current...

  4. Chemical composition, larvicidal evaluation, and adult repellency of endemic Greek Thymus essential oils against the mosquito vector of West Nile virus.

    PubMed

    Pitarokili, Danae; Michaelakis, Antonios; Koliopoulos, George; Giatropoulos, Athanassios; Tzakou, Olga

    2011-08-01

    The volatile metabolites of Greek wild growing Thymus leucospermus and Thymus teucrioides subsp. candilicus were determined by gas chromatography and gas chromatography-mass spectrometry. The monoterpene hydrocarbon p-cymene (64.2%) dominated T. leucospermus oil, followed by γ-terpinene (7.9%), thymol (4.8%), and borneol (4.7%), whereas the most abundant constituents in T. teucrioides subsp. candilicus oil were p-cymene (25.5%), γ-terpinene (19.0%), thymol (18.8%), borneol (5.7%), and α-pinene (5.7%). The larvicidal and repellent activities of the analyzed essential oils were tested on Culex pipiens larvae and adults, respectively. Additionally, the main metabolite of the essential oils, p-cymene was tested against C. pipiens adults in order to define the affiliation between p-cymene and the repellent properties of the oil. The essential oils of T. leucospermus and T. teucrioides subsp. candilicus provided repellency 78.1% and 72.9%, respectively, statistically equal to the reference product icaridin. The compound p-cymene showed almost no repellent activity. The essential oil of T. leucospermus presented lower larvicidal activity (LC(50) = 34.26 mgl(-1)) against C. pipiens third-fourth instar larvae while T. teucrioides subsp. candilicus was the most active with an estimated LC(50) value of 23.17 mgl(-1). PMID:21301870

  5. An insight into the sialome of Simulium guianense (DIPTERA:SIMulIIDAE), the main vector of River Blindness Disease in Brazil

    PubMed Central

    2011-01-01

    Background Little is known about the composition and function of the saliva in black flies such as Simulium guianense, the main vector of river blindness disease in Brazil. The complex salivary potion of hematophagous arthropods counteracts their host's hemostasis, inflammation, and immunity. Results Transcriptome analysis revealed ubiquitous salivary protein families--such as the Antigen-5, Yellow, Kunitz domain, and serine proteases--in the S. guianense sialotranscriptome. Insect-specific families were also found. About 63.4% of all secreted products revealed protein families found only in Simulium. Additionally, we found a novel peptide similar to kunitoxin with a structure distantly related to serine protease inhibitors. This study revealed a relative increase of transcripts of the SVEP protein family when compared with Simulium vittatum and S. nigrimanum sialotranscriptomes. We were able to extract coding sequences from 164 proteins associated with blood and sugar feeding, the majority of which were confirmed by proteome analysis. Conclusions Our results contribute to understanding the role of Simulium saliva in transmission of Onchocerca volvulus and evolution of salivary proteins in black flies. It also consists of a platform for mining novel anti-hemostatic compounds, vaccine candidates against filariasis, and immuno-epidemiologic markers of vector exposure. PMID:22182526

  6. Hey! A Mosquito Bit Me!

    MedlinePlus

    ... Here's Help White House Lunch Recipes Hey! A Mosquito Bit Me! KidsHealth > For Kids > Hey! A Mosquito ... español ¡Ay! ¡Me picó un mosquito! What's a Mosquito? A mosquito (say: mus-KEE-toe) is an ...

  7. West Nile Virus Fitness Costs in Different Mosquito Species.

    PubMed

    Coffey, Lark L; Reisen, William K

    2016-06-01

    West Nile virus (WNV) remains an important public health problem causing annual epidemics in the United States. Grubaugh et al. observed that WNV genetic divergence is dependent on the vector mosquito species. This suggests that specific WNV vector-bird species pairings may generate novel genotypes that could promote outbreaks. PMID:27108207

  8. Green-synthesized silver nanoparticles as a novel control tool against dengue virus (DEN-2) and its primary vector Aedes aegypti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dengue is an arthropod-borne viral infection mainly vectored through the bite of Aedes mosquitoes. Recently, its transmission has strongly increased in urban and semi-urban areas of tropical and sub-tropical regions worldwide, becoming a major international public health concern. There is no specifi...

  9. Evidence of Simultaneous Circulation of West Nile and Usutu Viruses in Mosquitoes Sampled in Emilia-Romagna Region (Italy) in 2009

    PubMed Central

    Calzolari, Mattia; Bonilauri, Paolo; Bellini, Romeo; Albieri, Alessandro; Defilippo, Francesco; Maioli, Giulia; Galletti, Giorgio; Gelati, Antoni; Barbieri, Ilaria; Tamba, Marco; Lelli, Davide; Carra, Elena; Cordioli, Paolo; Angelini, Paola; Dottori, Michele

    2010-01-01

    Background In recent years human diseases due to mosquito-borne viruses were increasingly reported in Emilia-Romagna region (Italy), from the chikungunya virus in 2007 to the West Nile virus (WNV) in 2008. An extensive entomological survey was performed in 2009 to establish the presence and distribution of mosquito arboviruses in this region, with particular reference to flaviviruses. Methodology/Principal Findings From May 6 to October 31, a total of 190,516 mosquitoes were sampled in georeferenced stations, grouped in 1,789 pools according date of collection, location, and species, and analyzed by reverse transcription polymerase chain reaction (RT-PCR) to detect the presence of RNA belong to Flavivirus genus. WNV was detected in 27 mosquito pools, producing sequences similar to those of birds and human strains obtained in 2008 outbreak, pointed out the probable virus overwintering. Isolation of WNV was achieved from one of these pools. Moreover 56 pools of mosquitoes tested positive for Usutu virus (USUV). Most PCR positive pools consisted of Culex pipiens, which also was the most analyzed mosquito species (81.4% of specimens); interestingly, USUV RNA was also found in two Aedes albopictus mosquito pools. Simultaneous circulation of WNV and USUV in the survey area was highlighted by occurrence of 8 mosquito WNV- and USUV-positive pools and by the overlaying of the viruses “hot spots”, obtained by kernel density estimation (KDE) analysis. Land use of sampled stations pointed out a higher proportion of WNV-positive Cx. pipiens pool in rural environments respect the provenience of total sampled pool, while the USUV-positive pools were uniformly captured in the different environments. Conclusions/Significance Obtained data highlighting the possible role of Cx. pipiens mosquito as the main vector for WNV and USUV in Northern Italy, and the possible involvement of Ae. albopictus mosquito in USUV cycle. The described mosquito-based surveillance could constitute the

  10. Complex effects of temperature on mosquito immune function

    PubMed Central

    Murdock, C. C.; Paaijmans, Krijn P.; Bell, Andrew S.; King, Jonas G.; Hillyer, Julián F.; Read, Andrew F.; Thomas, Matthew B.

    2012-01-01

    Over the last 20 years, ecological immunology has provided much insight into how environmental factors shape host immunity and host–parasite interactions. Currently, the application of this thinking to the study of mosquito immunology has been limited. Mechanistic investigations are nearly always conducted under one set of conditions, yet vectors and parasites associate in a variable world. We highlight how environmental temperature shapes cellular and humoral immune responses (melanization, phagocytosis and transcription of immune genes) in the malaria vector, Anopheles stephensi. Nitric oxide synthase expression peaked at 30°C, cecropin expression showed no main effect of temperature and humoral melanization, and phagocytosis and defensin expression peaked around 18°C. Further, immune responses did not simply scale with temperature, but showed complex interactions between temperature, time and nature of immune challenge. Thus, immune patterns observed under one set of conditions provide little basis for predicting patterns under even marginally different conditions. These quantitative and qualitative effects of temperature have largely been overlooked in vector biology but have significant implications for extrapolating natural/transgenic resistance mechanisms from laboratory to field and for the efficacy of various vector control tools. PMID:22593107

  11. Human to Mosquito Transmission of Dengue Viruses

    PubMed Central

    Carrington, Lauren B.; Simmons, Cameron P.

    2014-01-01

    The successful transmission of dengue virus from a human host to a mosquito vector requires a complex set of factors to align. It is becoming increasingly important to improve our understanding of the parameters that shape the human to mosquito component of the transmission cycle so that vaccines and therapeutic antivirals can be fully evaluated and epidemiological models refined. Here we describe these factors, and discuss the biological and environmental impacts and demographic changes that are influencing these dynamics. Specifically, we examine features of the human infection required for the mosquito to acquire the virus via natural blood feeding, as well as the biological and environmental factors that influence a mosquito’s susceptibility to infection, up to the point that they are capable of transmitting the virus to a new host. PMID:24987394

  12. Mosquito immune responses to arbovirus infections

    PubMed Central

    Blair, Carol D.; Olson, Ken E.

    2014-01-01

    The principal mosquito innate immune response to virus infections, RNA interference (RNAi), differs substantially from the immune response to bacterial and fungal infections. The exo-siRNA pathway constitutes the major anti-arboviral RNAi response and its essential genetic components have been identified. Recent research has also implicated the Piwi-interacting RNA pathway in mosquito anti-arboviral immunity, but Piwi gene-family components involved are not well-defined. Arboviruses must evade or suppress RNAi without causing pathogenesis in the vector to maintain their transmission cycle, but little is known about mechanisms of arbovirus modulation of RNAi. Genetic manipulation of mosquitoes to enhance their RNAi response can limit arbovirus infection and replication and could be used in novel strategies for interruption of arbovirus transmission and greatly reduce disease. PMID:25401084

  13. Mosquito larval source management for controlling malaria

    PubMed Central

    Tusting, Lucy S; Thwing, Julie; Sinclair, David; Fillinger, Ulrike; Gimnig, John; Bonner, Kimberly E; Bottomley, Christian; Lindsay, Steven W

    2015-01-01

    Background Malaria is an important cause of illness and death in people living in many parts of the world, especially sub-Saharan Africa. Long-lasting insecticide treated bed nets (LLINs) and indoor residual spraying (IRS) reduce malaria transmission by targeting the adult mosquito vector and are key components of malaria control programmes. However, mosquito numbers may also be reduced by larval source management (LSM), which targets mosquito larvae as they mature in aquatic habitats. This is conducted by permanently or temporarily reducing the availability of larval habitats (habitat modification and habitat manipulation), or by adding substances to standing water that either kill or inhibit the development of larvae (larviciding). Objectives To evaluate the effectiveness of mosquito LSM for preventing malaria. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; EMBASE; CABS Abstracts; and LILACS up to 24 October 2012. We handsearched the Tropical Diseases Bulletin from 1900 to 2010, the archives of the World Health Organization (up to 11 February 2011), and the literature database of the Armed Forces Pest Management Board (up to 2 March 2011). We also contacted colleagues in the field for relevant articles. Selection criteria We included cluster randomized controlled trials (cluster-RCTs), controlled before-and-after trials with at least one year of baseline data, and randomized cross-over trials that compared LSM with no LSM for malaria control. We excluded trials that evaluated biological control of anopheline mosquitoes with larvivorous fish. Data collection and analysis At least two authors assessed each trial for eligibility. We extracted data and at least two authors independently determined the risk of bias in the included studies. We resolved all disagreements through discussion with a third author. We analyzed the data using Review Manager 5 software

  14. Mosquito repellent activity of essential oils of aromatic plants growing in Argentina.

    PubMed

    Gillij, Y G; Gleiser, R M; Zygadlo, J A

    2008-05-01

    Mosquitoes are important vectors of diseases and nuisance pests. Repellents minimize contact with mosquitoes. Repellents based on essential oils (EO) are being developed as an alternative to DEET (N,N-diethyl-m-methylbenzamide), an effective compound that has disadvantages including toxic reactions, and damage to plastic and synthetic fabric. This work evaluated the repellency against Aedes aegypti of EO from aromatic plants that grow in Argentina: Acantholippia seriphioides, Achyrocline satureioides, Aloysia citriodora, Anemia tomentosa, Baccharis spartioides, Chenopodium ambrosioides, Eucalyptus saligna, Hyptis mutabilis, Minthostachys mollis, Rosmarinus officinalis, Tagetes minuta and Tagetes pusilla. Most EO were effective. Variations depending on geographic origin of the plant were detected. At a 90% EO concentration, A. satureoides and T. pusilla were the least repellent. At concentrations of 12.5% B. spartioides, R. officinalis and A. citriodora showed the longest repellency times. Comparisons of the principal components of each EO suggest that limonene and camphor were the main components responsible for the repellent effects. PMID:17583499

  15. Green Nanoparticles for Mosquito Control

    PubMed Central

    Soni, Namita; Prakash, Soam

    2014-01-01

    Here, we have used the green method for synthesis of silver and gold nanoparticles. In the present study the silver (Ag) and gold (Au) nanoparticles (NPs) were synthesized by using the aqueous bark extract of Indian spice dalchini (Cinnamomum zeylanicum) (C. zyelanicum or C. verum J. Presl). Additionally, we have used these synthesized nanoparticles for mosquito control. The larvicidal activity has been tested against the malaria vector Anopheles stephensi and filariasis vector Culex quinquefasciatus. The results were obtained using UV-visible spectrophotometer and the images were recorded with a transmission electron microscope (TEM). The efficacy tests were then performed at different concentrations and varying numbers of hours by probit analysis. The synthesized AgNPs were in spherical shape and average sizes (11.77 nm AgNPs and 46.48 nm AuNPs). The larvae of An. stephensi were found highly susceptible to the synthesized AgNPs and AuNPs than the Cx. quinquefasciatus. These results suggest that the C. zeylanicum synthesized silver and gold nanoparticles have the potential to be used as an ideal ecofriendly approach for the control of mosquito. PMID:25243210

  16. Green nanoparticles for mosquito control.

    PubMed

    Soni, Namita; Prakash, Soam

    2014-01-01

    Here, we have used the green method for synthesis of silver and gold nanoparticles. In the present study the silver (Ag) and gold (Au) nanoparticles (NPs) were synthesized by using the aqueous bark extract of Indian spice dalchini (Cinnamomum zeylanicum) (C. zyelanicum or C. verum J. Presl). Additionally, we have used these synthesized nanoparticles for mosquito control. The larvicidal activity has been tested against the malaria vector Anopheles stephensi and filariasis vector Culex quinquefasciatus. The results were obtained using UV-visible spectrophotometer and the images were recorded with a transmission electron microscope (TEM). The efficacy tests were then performed at different concentrations and varying numbers of hours by probit analysis. The synthesized AgNPs were in spherical shape and average sizes (11.77 nm AgNPs and 46.48 nm AuNPs). The larvae of An. stephensi were found highly susceptible to the synthesized AgNPs and AuNPs than the Cx. quinquefasciatus. These results suggest that the C. zeylanicum synthesized silver and gold nanoparticles have the potential to be used as an ideal ecofriendly approach for the control of mosquito. PMID:25243210

  17. Analyzing Mosquito (Diptera: Culicidae) Diversity in Pakistan by DNA Barcoding

    PubMed Central

    Ashfaq, Muhammad; Hebert, Paul D. N.; Mirza, Jawwad H.; Khan, Arif M.; Zafar, Yusuf; Mirza, M. Sajjad

    2014-01-01

    Background 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. Methodology/Principal Findings 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. Conclusions 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. PMID:24827460

  18. Studies on prophenoloxidase activation in the mosquito Aedes aegypti L.

    PubMed

    Ashida, M; Kinoshita, K; Brey, P T

    1990-03-30

    This study, the first of its kind in a mosquito vector species, demonstrates the feasibility of studying prophenoloxidase activation in an insect containing not more than a few microliters of hemolymph. Mosquito phenoloxidase was found to be in an inactive proenzyme form, prophenoloxidase. Mosquito prophenoloxidase required bivalent cation for its activation; Ca2+ was found to be the most efficient for activation. Concomitant amidase activity was also observed prior to phenoloxidase activity. Through Western blotting, using a cross-reactive silkworm antiprophenoloxidase antibody, our results strongly suggest that mosquito prophenoloxidase activation resulted from limited proteolysis. Protease inhibitor studies reinforced this contention showing the involvement of (a) serine protease(s) with trypsin-like activity in the activation of mosquito prophenoloxidase. PMID:2110057

  19. Importance of mosquito "quasispecies" in selecting an epidemic arthropod-borne virus.

    PubMed

    Vazeille, Marie; Zouache, Karima; Vega-Rúa, Anubis; Thiberge, Jean-Michel; Caro, Valérie; Yébakima, André; Mousson, Laurence; Piorkowski, Géraldine; Dauga, Catherine; Vaney, Marie-Christine; Manni, Mosè; Gasperi, Giuliano; de Lamballerie, Xavier; Failloux, Anna-Bella

    2016-01-01

    Most arthropod-borne viruses (arboviruses), perpetuated by alternation between a vertebrate host and an insect vector, are likely to emerge through minor genetic changes enabling the virus to adapt to new hosts. In the past decade, chikungunya virus (CHIKV; Alphavirus, Togaviridae) has emerged on La Réunion Island following the selection of a unique substitution in the CHIKV E1 envelope glycoprotein (E1-A226V) of an East-Central-South African (ECSA) genotype conferring a higher transmission rate by the mosquito Aedes albopictus. Assumed to have occurred independently on at least four separate occasions, this evolutionary convergence was suspected to be responsible for CHIKV worldwide expansion. However, assumptions on CHIKV emergence were mainly based on viral genetic changes and the role of the mosquito population quasispecies remained unexplored. Here we show that the nature of the vector population is pivotal in selecting the epidemic CHIKV. We demonstrate using microsatellites mosquito genotyping that Ae. albopictus populations are genetically differentiated, contributing to explain their differential ability to select the E1-226V mutation. Aedes albopictus, newly introduced in Congo coinciding with the first CHIKV outbreak, was not able to select the substitution E1-A226V nor to preferentially transmit a CHIKV clone harboring the E1-226V as did Ae. albopictus from La Réunion. PMID:27383735

  20. Importance of mosquito “quasispecies” in selecting an epidemic arthropod-borne virus

    PubMed Central

    Vazeille, Marie; Zouache, Karima; Vega-Rúa, Anubis; Thiberge, Jean-Michel; Caro, Valérie; Yébakima, André; Mousson, Laurence; Piorkowski, Géraldine; Dauga, Catherine; Vaney, Marie-Christine; Manni, Mosè; Gasperi, Giuliano; de Lamballerie, Xavier; Failloux, Anna-Bella

    2016-01-01

    Most arthropod-borne viruses (arboviruses), perpetuated by alternation between a vertebrate host and an insect vector, are likely to emerge through minor genetic changes enabling the virus to adapt to new hosts. In the past decade, chikungunya virus (CHIKV; Alphavirus, Togaviridae) has emerged on La Réunion Island following the selection of a unique substitution in the CHIKV E1 envelope glycoprotein (E1-A226V) of an East-Central-South African (ECSA) genotype conferring a higher transmission rate by the mosquito Aedes albopictus. Assumed to have occurred independently on at least four separate occasions, this evolutionary convergence was suspected to be responsible for CHIKV worldwide expansion. However, assumptions on CHIKV emergence were mainly based on viral genetic changes and the role of the mosquito population quasispecies remained unexplored. Here we show that the nature of the vector population is pivotal in selecting the epidemic CHIKV. We demonstrate using microsatellites mosquito genotyping that Ae. albopictus populations are genetically differentiated, contributing to explain their differential ability to select the E1-226V mutation. Aedes albopictus, newly introduced in Congo coinciding with the first CHIKV outbreak, was not able to select the substitution E1-A226V nor to preferentially transmit a CHIKV clone harboring the E1-226V as did Ae. albopictus from La Réunion. PMID:27383735

  1. Effects of landscape anthropization on mosquito community composition and abundance

    NASA Astrophysics Data System (ADS)

    Ferraguti, Martina; Martínez-de La Puente, Josué; Roiz, David; Ruiz, Santiago; Soriguer, Ramón; Figuerola, Jordi

    2016-07-01

    Anthropogenic landscape transformation has an important effect on vector-borne pathogen transmission. However, the effects of urbanization on mosquito communities are still only poorly known. Here, we evaluate how land-use characteristics are related to the abundance and community composition of mosquitoes in an area with endemic circulation of numerous mosquito-borne pathogens. We collected 340 829 female mosquitoes belonging to 13 species at 45 localities spatially grouped in 15 trios formed by 1 urban, 1 rural and 1 natural area. Mosquito abundance and species richness were greater in natural and rural areas than in urban areas. Environmental factors including land use, vegetation and hydrological characteristics were related to mosquito abundance and community composition. Given the differing competences of each species in pathogen transmission, these results provide valuable information on the transmission potential of mosquito-borne pathogens that will be of great use in public and animal health management by allowing, for instance, the identification of the priority areas for pathogen surveillance and vector control.

  2. Effects of landscape anthropization on mosquito community composition and abundance

    PubMed Central

    Ferraguti, Martina; Martínez-de la Puente, Josué; Roiz, David; Ruiz, Santiago; Soriguer, Ramón; Figuerola, Jordi

    2016-01-01

    Anthropogenic landscape transformation has an important effect on vector-borne pathogen transmission. However, the effects of urbanization on mosquito communities are still only poorly known. Here, we evaluate how land-use characteristics are related to the abundance and community composition of mosquitoes in an area with endemic circulation of numerous mosquito-borne pathogens. We collected 340 829 female mosquitoes belonging to 13 species at 45 localities spatially grouped in 15 trios formed by 1 urban, 1 rural and 1 natural area. Mosquito abundance and species richness were greater in natural and rural areas than in urban areas. Environmental factors including land use, vegetation and hydrological characteristics were related to mosquito abundance and community composition. Given the differing competences of each species in pathogen transmission, these results provide valuable information on the transmission potential of mosquito-borne pathogens that will be of great use in public and animal health management by allowing, for instance, the identification of the priority areas for pathogen surveillance and vector control. PMID:27373794

  3. Effects of landscape anthropization on mosquito community composition and abundance.

    PubMed

    Ferraguti, Martina; Martínez-de la Puente, Josué; Roiz, David; Ruiz, Santiago; Soriguer, Ramón; Figuerola, Jordi

    2016-01-01

    Anthropogenic landscape transformation has an important effect on vector-borne pathogen transmission. However, the effects of urbanization on mosquito communities are still only poorly known. Here, we evaluate how land-use characteristics are related to the abundance and community composition of mosquitoes in an area with endemic circulation of numerous mosquito-borne pathogens. We collected 340 829 female mosquitoes belonging to 13 species at 45 localities spatially grouped in 15 trios formed by 1 urban, 1 rural and 1 natural area. Mosquito abundance and species richness were greater in natural and rural areas than in urban areas. Environmental factors including land use, vegetation and hydrological characteristics were related to mosquito abundance and community composition. Given the differing competences of each species in pathogen transmission, these results provide valuable information on the transmission potential of mosquito-borne pathogens that will be of great use in public and animal health management by allowing, for instance, the identification of the priority areas for pathogen surveillance and vector control. PMID:27373794

  4. An overview of malaria transmission from the perspective of Amazon Anopheles vectors.

    PubMed

    Pimenta, Paulo F P; Orfano, Alessandra S; Bahia, Ana C; Duarte, Ana P M; Ríos-Velásquez, Claudia M; Melo, Fabrício F; Pessoa, Felipe A C; Oliveira, Giselle A; Campos, Keillen M M; Villegas, Luis Martínez; Rodrigues, Nilton Barnabé; Nacif-Pimenta, Rafael; Simões, Rejane C; Monteiro, Wuelton M; Amino, Rogerio; Traub-Cseko, Yara M; Lima, José B P; Barbosa, Maria G V; Lacerda, Marcus V G

    2015-02-01

    In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Anopheles species have been conducted, but with only short-lived success or no success at all. In this review, we review the literature on malaria transmission from the perspective of its Amazon vectors. Currently, it is possible to develop experimental Plasmodium vivax infection of the colonised and field-captured vectors in laboratories located close to Amazonian endemic areas. We are also reviewing studies related to the immune response to P. vivax infection of Anopheles aquasalis, a coastal mosquito species. Finally, we discuss the importance of the modulation of Plasmodium infection by the vector microbiota and also consider the anopheline genomes. The establishment of experimental mosquito infections with Plasmodium falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide interesting models for studying malaria in the Amazonian scenario is important. Understanding the molecular mechanisms involved in the development of the parasites in New World vectors is crucial in order to better determine the interaction process and vectorial competence. PMID:25742262

  5. An overview of malaria transmission from the perspective of Amazon Anopheles vectors

    PubMed Central

    Pimenta, Paulo FP; Orfano, Alessandra S; Bahia, Ana C; Duarte, Ana PM; Ríos-Velásquez, Claudia M; Melo, Fabrício F; Pessoa, Felipe AC; Oliveira, Giselle A; Campos, Keillen MM; Villegas, Luis Martínez; Rodrigues, Nilton Barnabé; Nacif-Pimenta, Rafael; Simões, Rejane C; Monteiro, Wuelton M; Amino, Rogerio; Traub-Cseko, Yara M; Lima, José BP; Barbosa, Maria GV; Lacerda, Marcus VG; Tadei, Wanderli P; Secundino, Nágila FC

    2015-01-01

    In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Ano- pheles species have been conducted, but with only short-lived success or no success at all. In this review, we review the literature on malaria transmission from the perspective of its Amazon vectors. Currently, it is possible to develop experimental Plasmodium vivax infection of the colonised and field-captured vectors in laboratories located close to Amazonian endemic areas. We are also reviewing studies related to the immune response to P. vivax infection of Anopheles aquasalis, a coastal mosquito species. Finally, we discuss the importance of the modulation of Plasmodium infection by the vector microbiota and also consider the anopheline genomes. The establishment of experimental mosquito infections with Plasmodium falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide interesting models for studying malaria in the Amazonian scenario is important. Understanding the molecular mechanisms involved in the development of the parasites in New World vectors is crucial in order to better determine the interaction process and vectorial competence. PMID:25742262

  6. How Mosquitoes Detect People

    MedlinePlus

    ... mosquito-borne diseases are endemic,” Ray says. — by Carol Torgan, Ph.D. Related Links Targeting the Mosquito's ... Assistant Editors: Vicki Contie, Tianna Hicklin, Ph.D., Carol Torgan, Ph.D. NIH Research Matters is a ...

  7. Performance of mosquito's pump

    NASA Astrophysics Data System (ADS)

    Kikuchi, Kenji

    2005-11-01

    The flow of human blood in Mosquito's proboscis on Hagen-Poiseuille flow is investigated by using micro PIV system to apply mosquito's sucking system for micro-TAS devises. We want to know how high the power of Mosquito's pump is and how small the resistance in a proboscis is, a structure of Mosquito's sucking pump, and its characteristics as mechanical pump. We made the mosquito suck blood of our arm to obtain the average value, made many slices of a mosquito with 2μm thickness after fixed by wax. We anatomized the mosquito's head and picked up the sucking pump under the microscope to know its volume. Mosquito's pump shows high performance compared with the artificial pumps. The surfaces of proboscis were taken by using SEM, AFM because it is important factor for interaction between flow and its wall. Visualization of the blood flows near the tip of and inside proboscis are taken by micro PIV system to know the flow rate. We estimate the power of pump and the friction drag of proboscis by using these data.

  8. Vector-free transmission and persistence of Japanese encephalitis virus in pigs

    PubMed Central

    Ricklin, Meret E.; García-Nicolás, Obdulio; Brechbühl, Daniel; Python, Sylvie; Zumkehr, Beatrice; Nougairede, Antoine; Charrel, Remi N.; Posthaus, Horst; Oevermann, Anna; Summerfield, Artur

    2016-01-01

    Japanese encephalitis virus (JEV), a main cause of severe viral encephalitis in humans, has a complex ecology, composed of a cycle involving primarily waterbirds and mosquitoes, as well as a cycle involving pigs as amplifying hosts. To date, JEV transmission has been exclusively described as being mosquito-mediated. Here we demonstrate that JEV can be transmitted between pigs in the absence of arthropod vectors. Pigs shed virus in oronasal secretions and are highly susceptible to oronasal infection. Clinical symptoms, virus tropism and central nervous system histological lesions are similar in pigs infected through needle, contact or oronasal inoculation. In all cases, a particularly important site of replication are the tonsils, in which JEV is found to persist for at least 25 days despite the presence of high levels of neutralizing antibodies. Our findings could have a major impact on the ecology of JEV in temperate regions with short mosquito seasons. PMID:26902924

  9. Vector-free transmission and persistence of Japanese encephalitis virus in pigs.

    PubMed

    Ricklin, Meret E; García-Nicolás, Obdulio; Brechbühl, Daniel; Python, Sylvie; Zumkehr, Beatrice; Nougairede, Antoine; Charrel, Remi N; Posthaus, Horst; Oevermann, Anna; Summerfield, Artur

    2016-01-01

    Japanese encephalitis virus (JEV), a main cause of severe viral encephalitis in humans, has a complex ecology, composed of a cycle involving primarily waterbirds and mosquitoes, as well as a cycle involving pigs as amplifying hosts. To date, JEV transmission has been exclusively described as being mosquito-mediated. Here we demonstrate that JEV can be transmitted between pigs in the absence of arthropod vectors. Pigs shed virus in oronasal secretions and are highly susceptible to oronasal infection. Clinical symptoms, virus tropism and central nervous system histological lesions are similar in pigs infected through needle, contact or oronasal inoculation. In all cases, a particularly important site of replication are the tonsils, in which JEV is found to persist for at least 25 days despite the presence of high levels of neutralizing antibodies. Our findings could have a major impact on the ecology of JEV in temperate regions with short mosquito seasons. PMID:26902924

  10. Field evaluation of three plant-based insect repellents against malaria vectors in Vaca Diez Province, the Bolivian Amazon.

    PubMed

    Moore, Sarah J; Lenglet, Annick; Hill, Nigel

    2002-06-01

    The efficacy of repellents against Anopheles darlingi, the main malaria vector in Bolivia, was evaluated. This mosquito has a peak in biting activity early in the evening. Three natural repellents (1 eucalyptus based, 1 neem based, and 1 containing several repellent essential oils) were tested in comparison with 15% deet in human landing catches in Bolivia. The eucalyptus-based repellent containing 30% p-menthane-diol applied at a dose similar to those used in practice gave 96.89% protection for 4 h. Deet gave 84.81% protection. The other 2 products did not provide significant protection from mosquito bites. PMID:12083351

  11. West Nile Virus Surveillance in 2013 via Mosquito Screening in Northern Italy and the Influence of Weather on Virus Circulation

    PubMed Central

    Calzolari, Mattia; Pautasso, Alessandra; Montarsi, Fabrizio; Albieri, Alessandro; Bellini, Romeo; Bonilauri, Paolo; Defilippo, Francesco; Lelli, Davide; Moreno, Ana; Chiari, Mario; Tamba, Marco; Zanoni, Mariagrazia; Varisco, Giorgio; Bertolini, Silvia; Modesto, Paola; Radaelli, Maria Cristina; Iulini, Barbara; Prearo, Marino; Ravagnan, Silvia; Cazzin, Stefania; Mulatti, Paolo; Monne, Isabella; Bonfanti, Lebana; Marangon, Stefano; Goffredo, Maria; Savini, Giovanni; Martini, Simone; Mosca, Andrea; Farioli, Marco; Gemma Brenzoni, Laura; Palei, Manlio; Russo, Francesca; Natalini, Silvano; Angelini, Paola; Casalone, Cristina; Dottori, Michele; Capelli, Gioia

    2015-01-01

    West Nile virus (WNV) is a recently re-emerged health problem in Europe. In Italy, an increasing number of outbreaks of West Nile disease, with occurrences of human cases, have been reported since 2008. This is particularly true in northern Italy, where entomological surveillance systems have been implemented at a regional level. The aim of this study was to use, for the first time, all the entomological data collected in the five regions undergoing surveillance for WNV in northern Italy to characterize the viral circulation (at a spatial and temporal scale), identify potential mosquito vectors, and specify relationships between virus circulation and meteorological conditions. In 2013, 286 sites covering the entire Pianura Padana area were monitored. A total of 757,461 mosquitoes were sampled. Of these, 562,079 were tested by real-time PCR in 9,268 pools, of which 180 (1.9%) were positive for WNV. The largest part of the detected WNV sequences belonged to lineage II, demonstrating that, unlike those in the past, the 2013 outbreak was mainly sustained by this WNV lineage. This surveillance also detected the Usutu virus, a WNV-related flavivirus, in 241 (2.6%) pools. The WNV surveillance systems precisely identified the area affected by the virus and detected the viral circulation approximately two weeks before the occurrence of onset of human cases. Ninety percent of the sampled mosquitoes were Culex pipiens, and 178/180 WNV-positive pools were composed of only this species, suggesting this mosquito is the main WNV vector in northern Italy. A significantly higher abundance of the vector was recorded in the WNV circulation area, which was characterized by warmer and less rainy conditions and greater evapotranspiration compared to the rest of the Pianura Padana, suggesting that areas exposed to these conditions are more suitable for WNV circulation. This observation highlights warmer and less rainy conditions as factors able to enhance WNV circulation and cause virus

  12. Willingness to Pay for Mosquito Control in Key West, Florida and Tucson, Arizona.

    PubMed

    Dickinson, Katherine L; Hayden, Mary H; Haenchen, Steven; Monaghan, Andrew J; Walker, Kathleen R; Ernst, Kacey C

    2016-04-01

    Mosquito-borne illnesses like West Nile virus (WNV) and dengue are growing threats to the United States. Proactive mosquito control is one strategy to reduce the risk of disease transmission. In 2012, we measured the public's willingness to pay (WTP) for increased mosquito control in two cities: Key West, FL, where there have been recent dengue outbreaks, and Tucson, AZ, where dengue vectors are established and WNV has been circulating for over a decade. Nearly three quarters of respondents in both cities (74% in Tucson and 73% in Key West) would be willing to pay $25 or more annually toward an increase in publicly funded mosquito control efforts. WTP was positively associated with income (both cities), education (Key West), and perceived mosquito abundance (Tucson). Concerns about environmental impacts of mosquito control were associated with lower WTP in Key West. Expanded mosquito control efforts should incorporate public opinion as they respond to evolving disease risks. PMID:26903603

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  14. Malaria-induced changes in host odors enhance mosquito attraction

    PubMed Central

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

    2014-01-01

    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. PMID:24982164

  15. An updated checklist of mosquito species (Diptera: Culicidae) from Madagascar

    PubMed Central

    Tantely, Michaël Luciano; Le Goff, Gilbert; Boyer, Sébastien; Fontenille, Didier

    2016-01-01

    An updated checklist of 235 mosquito species from Madagascar is presented. The number of species has increased considerably compared to previous checklists, particularly the last published in 2003 (178 species). This annotated checklist provides concise information on endemism, taxonomic position, developmental stages, larval habitats, distribution, behavior, and vector-borne diseases potentially transmitted. The 235 species belong to 14 genera: Aedeomyia (3 species), Aedes (35 species), Anopheles (26 species), Coquillettidia (3 species), Culex (at least 50 species), Eretmapodites (4 species), Ficalbia (2 species