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1

Differential Protein Modulation in Midguts of Aedes aegypti Infected with Chikungunya and Dengue 2  

E-print Network

Differential Protein Modulation in Midguts of Aedes aegypti Infected with Chikungunya and Dengue 2 diseases. Among the diseases caused by arboviruses, dengue and chikungunya are responsible for a high rate an oral infection (7 DPI) with dengue 2 (DENV-2) and chikungunya (CHIKV) viruses. Gel profile comparisons

Boyer, Edmond

2

Infection with dengue-2 virus alters proteins in naturally expectorated saliva of Aedes aegypti mosquitoes  

PubMed Central

Background Dengue virus (DENV) is responsible for up to approximately 300 million infections and an increasing number of deaths related to severe manifestations each year in affected countries throughout the tropics. It is critical to understand the drivers of this emergence, including the role of vector-virus interactions. When a DENV-infected Aedes aegypti mosquito bites a vertebrate, the virus is deposited along with a complex mixture of salivary proteins. However, the influence of a DENV infection upon the expectorated salivary proteome of its vector has yet to be determined. Methods Therefore, we conducted a proteomic analysis using 2-D gel electrophoresis coupled with mass spectrometry based protein identification comparing the naturally expectorated saliva of Aedes aegypti infected with DENV-2 relative to that of uninfected Aedes aegypti. Results Several proteins were found to be differentially expressed in the saliva of DENV-2 infected mosquitoes, in particular proteins with anti-hemostatic and pain inhibitory functions were significantly reduced. Hypothetical consequences of these particular protein reductions include increased biting rates and transmission success, and lead to alteration of transmission potential as calculated in our vectorial capacity model. Conclusions We present our characterizations of these changes with regards to viral transmission and mosquito blood-feeding success. Further, we conclude that our proteomic analysis of Aedes aegypti saliva altered by DENV infection provides a unique opportunity to identify pro-viral impacts key to virus transmission. PMID:24886023

2014-01-01

3

Isoenzyme variation in Aedes aegypti correlated with Dirofilaria immitis infectability.  

PubMed

From the Vero Beach strain of the mosquito Aedes (Stegomyia) aegypti (L.) (Diptera: Culicidae), substrains were selected for susceptibility (SS) and refractoriness (RR) to the dog heartworm Dirofilaria immitis (Leidy) (Filarioidea: Onchocercidae). These two lines and their reciprocal F1 hybrids were analysed for genetic variation at 14 enzyme loci, using polyacrylamide gel electrophoresis. Six of the enzyme loci showed variation (sample size 48 alleles/locus/line). Three of these were monomorphic in the refractory line but polymorphic in the susceptible, i.e. aconitase hydratase (Acoh), isocitrate dehydrogenase-1 (Idh-1) and phosphoglucomutase (Pgm). The other three loci, glucose-6-phosphate isomerase (Gpi), hexokinase-1 (Hk-1) and isocitrate dehydrogenase-2 (Idh-2), were polymorphic in both SS and RR lines and their hybrids. At two loci (Hk-1, Pgm) three alleles were detected, whereas the other polymorphic loci had only two alleles. For Hk-1, the most frequent allele was Hk-1(80) (0.563) in refractory and Hk-1(100) in the susceptible (0.521) and F1 hybrids. For Pgm the most frequent alleles were Pgm125 in the susceptible line (0.646) and Pgm100 in the F1 hybrids (0.563 and 0.604) and refractory line (1.000). The mean observed heterozygosity (Ho), the mean Hardy-Weinberg expected heterozygosity (He) and the mean number of alleles per locus in the refractory line were lower, but not significantly so, than in the susceptible line and their reciprocal F1 hybrids; the proportion of polymorphic loci was significantly lower in the refractory than in the susceptible line and their F1 hybrids. Within both lines all polymorphisms were in Hardy-Weinberg equilibrium, whereas significant departures from predicted frequencies were observed in SS x RR hybrids at four polymorphic loci (Acoh, Gpi, Hk-1, Pgm) and at three polymorphic loci (Acoh, Hk-1, Pgm) in RR x SS hybrids. The average Nei's and modified Rogers' genetic distances between the lines were 0.024 and 0.139, respectively. These electrophoretic data show that the refractory line (putatively lacking fi allele) can be distinguished from the susceptible line (fi/fi) and their hybrids (heterozygous fi) by isozyme marker frequencies, but it remains to be seen whether this difference is causal or chance linkage. In any case, this model system of Ae. aegypti/D. immitis provides opportunities to better understand and manipulate the molecular biology of filariasis transmission. PMID:12510895

Nayar, J K; Knight, J W

2002-12-01

4

Differential Protein Modulation in Midguts of Aedes aegypti Infected with Chikungunya and Dengue 2 Viruses  

PubMed Central

Background Arthropod borne virus infections cause several emerging and resurgent infectious diseases. Among the diseases caused by arboviruses, dengue and chikungunya are responsible for a high rate of severe human diseases worldwide. The midgut of mosquitoes is the first barrier for pathogen transmission and is a target organ where arboviruses must replicate prior to infecting other organs. A proteomic approach was undertaken to characterize the key virus/vector interactions and host protein modifications that happen in the midgut for viral transmission to eventually take place. Methodology and Principal Findings Using a proteomics differential approach with two-Dimensional Differential in-Gel Electrophoresis (2D-DIGE), we defined the protein modulations in the midgut of Aedes aegypti that were triggered seven days after an oral infection (7 DPI) with dengue 2 (DENV-2) and chikungunya (CHIKV) viruses. Gel profile comparisons showed that the level of 18 proteins was modulated by DENV-2 only and 12 proteins were modulated by CHIKV only. Twenty proteins were regulated by both viruses in either similar or different ways. Both viruses caused an increase of proteins involved in the generation of reactive oxygen species, energy production, and carbohydrate and lipid metabolism. Midgut infection by DENV-2 and CHIKV triggered an antioxidant response. CHIKV infection produced an increase of proteins involved in detoxification. Conclusion/Significance Our study constitutes the first analysis of the protein response of Aedes aegypti's midgut infected with viruses belonging to different families. It shows that the differentially regulated proteins in response to viral infection include structural, redox, regulatory proteins, and enzymes for several metabolic pathways. Some of these proteins like antioxidant are probably involved in cell protection. On the other hand, we propose that the modulation of other proteins like transferrin, hsp60 and alpha glucosidase, may favour virus survival, replication and transmission, suggesting a subversion of the insect cell metabolism by the arboviruses. PMID:20957153

Tchankouo-Nguetcheu, Stephane; Khun, Huot; Pincet, Laurence; Roux, Pascal; Bahut, Muriel; Huerre, Michel; Guette, Catherine; Choumet, Valerie

2010-01-01

5

Detection of Dengue Virus NS1 Antigen in Infected Aedes aegypti Using a Commercially Available Kit  

PubMed Central

Epidemic dengue has emerged throughout the tropical world. In the continued absence of a vaccine against dengue virus (DENV), mosquito vector surveillance and control programs are essential to reduce human infections. An effective test to detect DENV in infected mosquitoes would be a valuable addition to the surveillance effort. We investigated DENV detection in infected Aedes aegypti using a commercially available DENV non-structural protein 1 (NS1) ELISA kit (Platelia Dengue NS1 Ag), and by reverse transcription-polymerase chain reaction (RT-PCR) and virus isolation assays. The DENV-infected mosquitoes were subjected to field-relevant conditions and assayed individually and pooled with uninfected mosquitoes. Overall, DENV NS1 antigen was detected in 98% of infected mosquitoes/pools versus 79% for RT-PCR and 29% for virus isolation. Our results indicate that NS1 is an excellent analyte for detection of DENV in Ae. aegypti and that the tested NS1 antigen kit provides a sensitive, rapid, and convenient test for DENV surveillance in mosquitoes. PMID:23185074

Voge, Natalia V.; Sanchez-Vargas, Irma; Blair, Carol D.; Eisen, Lars; Beaty, Barry J.

2013-01-01

6

Global Cross-Talk of Genes of the Mosquito Aedes aegypti in Response to Dengue Virus Infection  

Microsoft Academic Search

BackgroundThe mosquito Aedes aegypti is the primary vector of dengue virus (DENV) infection in humans, and DENV is the most important arbovirus across most of the subtropics and tropics worldwide. The early time periods after infection with DENV define critical cellular processes that determine ultimate success or failure of the virus to establish infection in the mosquito.Methods and ResultsTo identify

Susanta K. Behura; Consuelo Gomez-Machorro; Brent W. Harker; Becky deBruyn; Diane D. Lovin; Ryan R. Hemme; Akio Mori; Jeanne Romero-Severson; David W. Severson

2011-01-01

7

Infection by chikungunya virus modulates the expression of several proteins in Aedes aegypti salivary glands  

PubMed Central

Background Arthropod-borne viral infections cause several emerging and resurging infectious diseases. Among the diseases caused by arboviruses, chikungunya is responsible for a high level of severe human disease worldwide. The salivary glands of mosquitoes are the last barrier before pathogen transmission. Methods We undertook a proteomic approach to characterize the key virus/vector interactions and host protein modifications that occur in the salivary glands that could be responsible for viral transmission by using quantitative two-dimensional electrophoresis. Results We defined the protein modulations in the salivary glands of Aedes aegypti that were triggered 3 and 5 days after an oral infection (3 and 5 DPI) with chikungunya virus (CHIKV). Gel profile comparisons showed that CHIKV at 3 DPI modulated the level of 13 proteins, and at 5 DPI 20 proteins. The amount of 10 putatively secreted proteins was regulated at both time points. These proteins were implicated in blood-feeding or in immunity, but many have no known function. CHIKV also modulated the quantity of proteins involved in several metabolic pathways and in cell signalling. Conclusion Our study constitutes the first analysis of the protein response of Aedes aegypti salivary glands infected with CHIKV. We found that the differentially regulated proteins in response to viral infection include structural proteins and enzymes for several metabolic pathways. Some may favour virus survival, replication and transmission, suggesting a subversion of the insect cell metabolism by arboviruses. For example, proteins involved in blood-feeding such as the short D7, an adenosine deaminase and inosine-uridine preferring nucleoside hydrolase, may favour virus transmission by exerting an increased anti-inflammatory effect. This would allow the vector to bite without the bite being detected. Other proteins, like the anti-freeze protein, may support vector protection. PMID:23153178

2012-01-01

8

A simple method for the detection of Leptolegnia chapmanii from infected Aedes aegypti larvae.  

PubMed

Significant progress in developing Leptolegnia chapmanii as a biological control agent against mosquitoes will be accelerated by improved and simpler methods to detect and to isolate this virulent and rapidly lethal watermold from field-collected mosquito larvae. To date, however, this oomycete has remained understudied and little used. This study presents a simplified method to detect Leptolegnia in infected Aedes aegypti larvae. The development of L. chapmanii inside mosquitoes is easily monitored when pathogen-treated larvae are quasi-immobilized for an initial 48 h in the water film on plates of water agar amended with antibiotic (chloramphenicol, 0.5-1 g/L) and fungicide (thiabendazole, 4-8 g/L) and then transferred to a larger volume of water for an additional 48 h. Surprisingly, chloramphenicol stimulated oosporogenesis by L. chapmanii. The method permits processing of large numbers of A. aegypti and other culicid larvae and is useful for both obtaining new strains and also monitoring the efficacy of L. chapmanii during field tests. PMID:23750958

Leles, Renan N; López Lastra, Cláudia C; García, Juan J; Fernandes, Everton K K; Luz, Christian

2013-06-01

9

Mosquito Infestation and Dengue Virus Infection in Aedes aegypti Females in Schools in M?rida, M?xico  

PubMed Central

We determined abundance of Aedes aegypti mosquitoes and presence of dengue virus (DENV) in females collected from schools in Mérida, México, during 2008 and 2009. Backpack aspiration from 24 schools produced 468 females of Ae. aegypti and 1,676 females of another human biter, Culex quinquefasciatus. Ae. aegypti females were collected most commonly from classrooms followed by offices and bathrooms. Of these females, 24.7% were freshly fed. Examination of 118 pools of Ae. aegypti females (total of 415 females) for presence of DENV RNA produced 19 positive pools (16.1%). DENV-infected pools were detected from 11 (45.8%) of 24 schools and came from different room types, including classrooms, offices, and bathrooms. The overall rate of DENV infection per 100 Ae. aegypti females was 4.8. We conclude that schools in Mérida present a risk environment for students, teachers, and other personnel to be exposed to mosquitoes and bites of DENV-infected Ae. aegypti females. PMID:21363990

Garcia-Rejon, Julian E.; Lorono-Pino, Maria Alba; Farfan-Ale, Jose Arturo; Flores-Flores, Luis F.; Lopez-Uribe, Mildred P.; del Rosario Najera-Vazquez, Maria; Nunez-Ayala, Guadalupe; Beaty, Barry J.; Eisen, Lars

2011-01-01

10

Impact of Wolbachia on Infection with Chikungunya and Yellow Fever Viruses in the Mosquito Vector Aedes aegypti  

PubMed Central

Incidence of disease due to dengue (DENV), chikungunya (CHIKV) and yellow fever (YFV) viruses is increasing in many parts of the world. The viruses are primarily transmitted by Aedes aegypti, a highly domesticated mosquito species that is notoriously difficult to control. When transinfected into Ae. aegypti, the intracellular bacterium Wolbachia has recently been shown to inhibit replication of DENVs, CHIKV, malaria parasites and filarial nematodes, providing a potentially powerful biocontrol strategy for human pathogens. Because the extent of pathogen reduction can be influenced by the strain of bacterium, we examined whether the wMel strain of Wolbachia influenced CHIKV and YFV infection in Ae. aegypti. Following exposure to viremic blood meals, CHIKV infection and dissemination rates were significantly reduced in mosquitoes with the wMel strain of Wolbachia compared to Wolbachia-uninfected controls. However, similar rates of infection and dissemination were observed in wMel infected and non-infected Ae. aegypti when intrathoracic inoculation was used to deliver virus. YFV infection, dissemination and replication were similar in wMel-infected and control mosquitoes following intrathoracic inoculations. In contrast, mosquitoes with the wMelPop strain of Wolbachia showed at least a 104 times reduction in YFV RNA copies compared to controls. The extent of reduction in virus infection depended on Wolbachia strain, titer and strain of the virus, and mode of exposure. Although originally proposed for dengue biocontrol, our results indicate a Wolbachia-based strategy also holds considerable promise for YFV and CHIKV suppression. PMID:23133693

van den Hurk, Andrew F.; Hall-Mendelin, Sonja; Pyke, Alyssa T.; Frentiu, Francesca D.; McElroy, Kate; Day, Andrew; Higgs, Stephen; O'Neill, Scott L.

2012-01-01

11

Operational use of household bleach to "crash and release" Aedes aegypti prior to Wolbachia-infected mosquito release.  

PubMed

Dengue (family Flaviviridae, genus Flavivirus, DENV) remains the leading arboviral cause of mortality in the tropics. Wolbachia pipientis has been shown to interrupt DENV transmission and is presently being trialled as a biological control. However, deployment issues have arisen on methods to temporarily suppress wild mosquito populations before Wolbachia-infected mosquito releases. By suppressing wild populations, fewer Ae. aegypti releases are required to achieve a sustainable Wolbachia density threshold. Furthermore, public distress is reduced. This study tests the application of domestic bleach (4% NaCIO) to temporarily "crash" immature Aedes populations in water-filled containers. Spray application NaClO (215 ppm) resulted in a mean 48-h mortality of 100, 100, 97, and 88% of eggs, second-instar larvae, fourth-instar larvae, and pupae, respectively. In the field, NaClO delayed ovipositing by 9 d in cooler months, and 11 d in hotter months, after which oviposition resumed in treated receptacles. We found bleach treatment of pot-plant bases did not cause wilting, yellowing, or dropping of leaves in two ornamental plants species. Domestically available NaClO could be adopted for a "crash and release" strategy to temporarily suppress wild populations of Ae. aegypti in containers before release of Wolbachia-infected mosquitoes. The "crash and release" strategy is also applicable to other mosquito species, e.g., Aedes albopictus (Skuse), in strategies using released mosquitoes. PMID:23540123

Jacups, Susan P; Ball, Tamara S; Paton, Christopher J; Johnson, Petrina H; Ritchie, Scott A

2013-03-01

12

Impacts of Wolbachia infection on predator prey relationships: evaluating survival and horizontal transfer between wMelPop infected Aedes aegypti and its predators.  

PubMed

The wMelPop strain of Wolbachia is currently being investigated for its potential use as a biological control agent to reduce the ability of Aedes aegypti (L.) mosquitoes to transmit dengue viruses. The survival of a potential wMelPop infected Ae. aegypti strain for field release is important as a higher susceptibility to predation in the wMelPop strain could result in difficulties in achieving fixation. We investigated immature and adult survival as a function of susceptibility to predation by six naturally occurring predator species; cyclopoid copepods, fish, predatory Toxorhynchites mosquito larvae and a salticid jumping spider. The trials indicated that wMelPop infected and uninfected Ae. aegypti larvae and adults were equally susceptible to predation to all six tested predators. In addition to evaluating any potential fitness costs to the infected host, we were unable to demonstrate horizontal transfer of wMelPop via consumption of infected Ae. aegypti larvae to the above predators. That susceptibility to predation was consistent across mosquito life stage, predator species and experimental venue is strong evidence that despite the neurotrophic and extensive nature of wMelPop infection, behavioral changes are not occurring, or at least not a determining factor in survival when exposed to a predator. Based on our results and the ecology of Wolbachia and mosquito predators, horizontal transfer of wMelPop from Ae. aegypti into naturally occurring predators is not cause for concern. PMID:22679870

Hurst, Timothy P; Pittman, Geoff; O'Neill, Scott L; Ryan, Peter A; Nguyen, Hoang Le; Kay, Brian H

2012-05-01

13

Suppressing Dengue-2 Infection by Chemical Inhibition of Aedes aegypti Host Factors  

PubMed Central

Dengue virus host factors (DENV HFs) that are essential for the completion of the infection cycle in the mosquito vector and vertebrate host represent potent targets for transmission blocking. Here we investigated whether known mammalian DENV HF inhibitors could influence virus infection in the arthropod vector A. aegypti. We evaluated the potency of bafilomycin (BAF; inhibitor of vacuolar H+-ATPase (vATPase)), mycophenolic acid (MPA; inhibitor of inosine-5?-monophosphate dehydrogenase (IMPDH)), castanospermine (CAS; inhibitor of glucosidase), and deoxynojirimycin (DNJ; inhibitor of glucosidase) in blocking DENV infection of the mosquito midgut, using various treatment methods that included direct injection, ingestion by sugar feeding or blood feeding, and silencing of target genes by RNA interference (RNAi). Injection of BAF (5 µM) and MPA (25 µM) prior to feeding on virus-infected blood inhibited DENV titers in the midgut at 7 days post-infection by 56% and 60%, and in the salivary gland at 14 days post-infection by 90% and 83%, respectively, while treatment of mosquitoes with CAS or DNJ did not affect susceptibility to the virus. Ingestion of BAF and MPA through a sugar meal or together with an infectious blood meal also resulted in various degrees of virus inhibition. RNAi-mediated silencing of several vATPase subunit genes and the IMPDH gene resulted in a reduced DENV infection, thereby indicating that BAF- and MPA-mediated virus inhibition in adult mosquitoes most likely occurred through the inhibition of these DENV HFs. The route and timing of BAF and MPA administration was essential, and treatment after exposure to the virus diminished the antiviral effect of these compounds. Here we provide proof-of-principle that chemical inhibition or RNAi-mediated depletion of the DENV HFs vATPase and IMPDH can be used to suppress DENV infection of adult A. aegypti mosquitoes, which may translate to a reduction in DENV transmission. PMID:25101828

Kang, Seokyoung; Shields, Alicia R.; Jupatanakul, Natapong; Dimopoulos, George

2014-01-01

14

Suppressing dengue-2 infection by chemical inhibition of Aedes aegypti host factors.  

PubMed

Dengue virus host factors (DENV HFs) that are essential for the completion of the infection cycle in the mosquito vector and vertebrate host represent potent targets for transmission blocking. Here we investigated whether known mammalian DENV HF inhibitors could influence virus infection in the arthropod vector A. aegypti. We evaluated the potency of bafilomycin (BAF; inhibitor of vacuolar H+-ATPase (vATPase)), mycophenolic acid (MPA; inhibitor of inosine-5'-monophosphate dehydrogenase (IMPDH)), castanospermine (CAS; inhibitor of glucosidase), and deoxynojirimycin (DNJ; inhibitor of glucosidase) in blocking DENV infection of the mosquito midgut, using various treatment methods that included direct injection, ingestion by sugar feeding or blood feeding, and silencing of target genes by RNA interference (RNAi). Injection of BAF (5 µM) and MPA (25 µM) prior to feeding on virus-infected blood inhibited DENV titers in the midgut at 7 days post-infection by 56% and 60%, and in the salivary gland at 14 days post-infection by 90% and 83%, respectively, while treatment of mosquitoes with CAS or DNJ did not affect susceptibility to the virus. Ingestion of BAF and MPA through a sugar meal or together with an infectious blood meal also resulted in various degrees of virus inhibition. RNAi-mediated silencing of several vATPase subunit genes and the IMPDH gene resulted in a reduced DENV infection, thereby indicating that BAF- and MPA-mediated virus inhibition in adult mosquitoes most likely occurred through the inhibition of these DENV HFs. The route and timing of BAF and MPA administration was essential, and treatment after exposure to the virus diminished the antiviral effect of these compounds. Here we provide proof-of-principle that chemical inhibition or RNAi-mediated depletion of the DENV HFs vATPase and IMPDH can be used to suppress DENV infection of adult A. aegypti mosquitoes, which may translate to a reduction in DENV transmission. PMID:25101828

Kang, Seokyoung; Shields, Alicia R; Jupatanakul, Natapong; Dimopoulos, George

2014-08-01

15

High-Throughput PCR Assays To Monitor Wolbachia Infection in the Dengue Mosquito (Aedes aegypti) and Drosophila simulans  

PubMed Central

We have developed and validated two new fluorescence-based PCR assays to detect the Wolbachia wMel strain in Aedes aegypti and the wRi and wAu strains in Drosophila simulans. The new assays are accurate, informative, and cost-efficient for large-scale Wolbachia screening. PMID:22522691

White, Vanessa L.; Weeks, Andrew R.; Hoffmann, Ary A.; Endersby, Nancy M.

2012-01-01

16

Wolbachia infection does not alter attraction of the mosquito Aedes (Stegomyia) aegypti to human odours.  

PubMed

The insect endosymbiont Wolbachia pipientis (Rickettsiales: Rickettsiaceae) is undergoing field trials around the world to determine if it can reduce transmission of dengue virus from the mosquito Stegomyia aegypti to humans. Two different Wolbachia strains have been released to date. The primary effect of the wMel strain is pathogen protection whereby infection with the symbiont limits replication of dengue virus inside the mosquito. A second strain, wMelPop, induces pathogen protection, reduces the adult mosquito lifespan and decreases blood feeding success in mosquitoes after 15 days of age. Here we test whether Wolbachia infection affects mosquito attraction to host odours in adults aged 5 and 15 days. We found no evidence of reduced odour attraction of mosquitoes, even for those infected with the more virulent wMelPop. This bodes well for fitness and competitiveness in the field given that the mosquitoes must find hosts to reproduce for the biocontrol method to succeed. PMID:24797695

Turley, A P; Smallegange, R C; Takken, W; Zalucki, M P; O'Neill, S L; McGraw, E A

2014-12-01

17

[Susceptibility to the infection of Anopheles nuneztovari Gabaldón and Aedes aegypti L with Romanomermis iyengari Welch (Rhabditida: Mermitidae)].  

PubMed

A laboratory-based study was performed in order to assess the infestation capacity of the mosquito parasite nematode Romanomermis iyengari Welch, on Anopheles nuneztovari Gabaldón and Aedes aegypti L. For each mosquito species, nine hundred (900) I to III instars larvae were taken. These larvae were infested with pre-parasitic larvae of R. iyengari in proportions of 5:1 and 10:1. The infestation averages obtained were 3.9 and 6.7 for Anopheles nuneztovari, and 1.9 and 4.7 for Aedes aegypti respectively. Mortality ranked between 95 and 100% for both mosquito species and Anopheles nuneztovari showed the highest susceptibility to the nematode parasitism. PMID:12520998

Rojas-Urdaneta, Janeth E; Sojo-Milano, Mayira; Mazzarri-Pelossa, Milena; Soca D, Lázaro A; García-Avila, Ysrael

2002-12-01

18

Persistence of Viral RNA in Chikungunya Virus-Infected Aedes aegypti (Diptera: Culicidae) Mosquitoes after Prolonged Storage at 28?C  

PubMed Central

Experiments were conducted to determine the persistence of chikungunya viral (CHIKV) RNA in experimentally infected Aedes aegypti mosquitoes stored for prolonged periods at 28°C. Intra-thoracically inoculated mosquitoes with confirmed positivity were killed by quick freezing at -80°C, applied to sticky tape, and stored at 28°C with 80 ± 5% relative humidity (RH). At weekly intervals, five mosquitoes were removed from the tape randomly and assayed individually for detection of viral RNA by reverse transcriptase-polymerase chain reaction (RT-PCR). CHIKV RNA was detected up to 12 weeks in dry mosquitoes by RT-PCR. Virus could not be isolated either in cell culture or in the suckling Swiss-albino mouse system at any stage. This study demonstrated the persistence of CHIKV viral RNA up to 12 weeks when stored at 28°C with RH 80 ± 5%. This finding will have significance in CHIKV surveillance programs in mosquito populations or field-based studies in countries where maintenance of a cold chain is a concern. PMID:22232470

Mavale, Mangala; Sudeep, Anakkathil; Gokhale, Mangesh; Hundekar, Supriya; Parashar, Deepti; Ghodke, Youwaraj; Arankalle, Vidya; Mishra, Akhilesh Chandra

2012-01-01

19

Comparative Genome Analysis of the Yellow Fever Mosquito Aedes aegypti  

E-print Network

Comparative Genome Analysis of the Yellow Fever Mosquito Aedes aegypti with Drosophila melanogaster aegypti, and Culex pipiens, the primary vectors for malaria, yellow fever and dengue, and lymphatic 103

Severson, David

20

Induction of a Peptide with Activity against a Broad Spectrum of Pathogens in the Aedes aegypti Salivary Gland, following Infection with Dengue Virus  

PubMed Central

The ultimate stage of the transmission of Dengue Virus (DENV) to man is strongly dependent on crosstalk between the virus and the immune system of its vector Aedes aegypti (Ae. aegypti). Infection of the mosquito's salivary glands by DENV is the final step prior to viral transmission. Therefore, in the present study, we have determined the modulatory effects of DENV infection on the immune response in this organ by carrying out a functional genomic analysis of uninfected salivary glands and salivary glands of female Ae. aegypti mosquitoes infected with DENV. We have shown that DENV infection of salivary glands strongly up-regulates the expression of genes that encode proteins involved in the vector's innate immune response, including the immune deficiency (IMD) and Toll signalling pathways, and that it induces the expression of the gene encoding a putative anti-bacterial, cecropin-like, peptide (AAEL000598). Both the chemically synthesized non-cleaved, signal peptide-containing gene product of AAEL000598, and the cleaved, mature form, were found to exert, in addition to antibacterial activity, anti-DENV and anti-Chikungunya viral activity. However, in contrast to the mature form, the immature cecropin peptide was far more effective against Chikungunya virus (CHIKV) and, furthermore, had strong anti-parasite activity as shown by its ability to kill Leishmania spp. Results from circular dichroism analysis showed that the immature form more readily adopts a helical conformation which would help it to cause membrane permeabilization, thus permitting its transfer across hydrophobic cell surfaces, which may explain the difference in the anti-pathogenic activity between the two forms. The present study underscores not only the importance of DENV-induced cecropin in the innate immune response of Ae. aegypti, but also emphasizes the broad-spectrum anti-pathogenic activity of the immature, signal peptide-containing form of this peptide. PMID:21249175

Patramool, Sirilaksana; Dumas, Emilie; Wasinpiyamongkol, Ladawan; Saune, Laure; Hamel, Rodolphe; Bernard, Eric; Sereno, Denis; Thomas, Frederic; Piquemal, David; Yssel, Hans; Briant, Laurence; Misse, Dorothee

2011-01-01

21

Spatial Stability of Adult Aedes aegypti Populations  

PubMed Central

Vector control programs could be more efficient by identifying the location of highly productive sites of Aedes aegypti. This study explored if the number of female adults of Ae. aegypti in BG-Sentinel traps was clustered and if their spatial distribution changed in time in two neighborhoods in San Juan, Puerto Rico. Traps were uniformly distributed across each neighborhood (130 m from each other), and samples were taken every 3 weeks. Global and local spatial autocorrelations were explored. Spatial stability existed if the rank order of trap captures was kept in time. There was lack of global autocorrelation in both neighborhoods, precluding their stratification for control purposes. Hot and cold spots were identified, revealing the highly focal nature of Ae. aegypti. There was significant spatial stability throughout the study in both locations. The consistency in trap productivity in time could be used to increase the effectiveness of vector and dengue control programs. PMID:22144449

Barrera, Roberto

2011-01-01

22

Burchellin: study of bioactivity against Aedes aegypti  

PubMed Central

Background The dengue mosquito Aedes aegypti Linnaeus, 1762 is a widespread insect pest of serious medical importance. Since no effective vaccine is available for treating dengue, the eradication or control of the main mosquito vector is regarded as essential. Since conventional insecticides have limited success, plants may be an alternative source of larvicidal agents, since they contain a rich source of bioactive chemicals. The aim of this study was to evaluate the larvicidal activity of the neolignan burchellin isolated from Ocotea cymbarum (Lauraceae), a plant from the Amazon region, against third instar larvae of A. aegypti. Methods Burchellin obtained from O. cymbarum was analyzed. The inhibitory activity against A. aegypti eggs and larvae and histological changes in the digestive system of treated L3 larvae were evaluated. In addition, nitric oxide synthase activity and nitric oxide levels were determined, and cytotoxicity bioassays performed. Results The data showed that burchellin interfered with the development cycle of the mosquito, where its strongest toxic effect was 100% mortality in larvae (L3) at concentrations???30 ppm. This compound did not show target cell toxicity in peritoneal macrophages from BALB/c mice, and proved to have molecular stability when dissolved in water. The L3 and L4 larvae treated with the compound showed cellular destruction and disorganization, cell spacing, and vacuolization of epithelial cells in small regions of the midgut. Conclusion The neolignan burchellin proved to be a strong candidate for a natural, safe and stable phytolarvicidal to be used in population control of A. aegypti. PMID:24713267

2014-01-01

23

Experimental Transmission of Mayaro Virus by Aedes aegypti  

PubMed Central

Outbreaks of Mayaro fever have been associated with a sylvatic cycle of Mayaro virus (MAYV) transmission in South America. To evaluate the potential for a common urban mosquito to transmit MAYV, laboratory vector competence studies were performed with Aedes aegypti from Iquitos, Peru. Oral infection in Ae. aegypti ranged from 0% (0/31) to 84% (31/37), with blood meal virus titers between 3.4 log10 and 7.3 log10 plaque-forming units (PFU)/mL. Transmission of MAYV by 70% (21/30) of infected mosquitoes was shown by saliva collection and exposure to suckling mice. Amount of viral RNA in febrile humans, determined by real-time polymerase chain reaction, ranged from 2.7 to 5.3 log10 PFU equivalents/mL. Oral susceptibility of Ae. aegypti to MAYV at titers encountered in viremic humans may limit opportunities to initiate an urban cycle; however, transmission of MAYV by Ae. aegypti shows the vector competence of this species and suggests potential for urban transmission. PMID:21976583

Long, Kanya C.; Ziegler, Sarah A.; Thangamani, Saravanan; Hausser, Nicole L.; Kochel, Tadeusz J.; Higgs, Stephen; Tesh, Robert B.

2011-01-01

24

Assessing quality of life-shortening Wolbachia-infected Aedes aegypti mosquitoes in the field based on capture rates and morphometric assessments  

PubMed Central

Background Recent releases have been carried out with Aedes aegypti mosquitoes infected with the wMelPop mosquito cell-line adapted (wMelPop-CLA) strain of Wolbachia. This infection introduced from Drosophila provides strong blockage of dengue and other arboviruses but also has large fitness costs in laboratory tests. The releases were used to evaluate the fitness of released infected mosquitoes, and (following termination of releases) to test for any effects of wMelPop-CLA on wing size and shape when mosquitoes were reared under field conditions. Methods We monitored gravid females via double sticky traps to assess the reproductive success of wMelPop-CLA-infected females and also sampled the overall mosquito population post-release using Biogent Sentinel traps. Morphometric analyses were used to evaluate infection effects on wing shape as well as size. Results Oviposition success as assessed through double sticky traps was unrelated to size of released mosquitoes. However, released mosquitoes with lower wing loading were more successful. Furthermore, wMelPop-CLA-infected mosquitoes had 38.3% of the oviposition success of uninfected mosquitoes based on the predicted infection frequency after release. Environmental conditions affected wing shape and particularly size across time in uninfected mosquitoes, but not in naturally-reared wMelPop-CLA-infected mosquitoes. Although the overall size and shape do not differ between naturally-reared wMelPop-CLA-infected and uninfected mosquitoes, the infected mosquitoes tended to have smaller wings than uninfected mosquitoes during the cooler November in comparison to December. Conclusion These results confirm the lower fitness of wMelPop-CLA infection under field conditions, helping to explain challenges associated with a successful invasion by this strain. In the long run, invasion may depend on releasing strains carrying insecticide resistance or egg desiccation resistance, combined with an active pre-release population suppression program. PMID:24495395

2014-01-01

25

Dengue Virus Inhibits Immune Responses in Aedes aegypti Cells  

PubMed Central

The ability of many viruses to manipulate the host antiviral immune response often results in complex host-pathogen interactions. In order to study the interaction of dengue virus (DENV) with the Aedes aegypti immune response, we have characterized the DENV infection-responsive transcriptome of the immune-competent A. aegypti cell line Aag2. As in mosquitoes, DENV infection transcriptionally activated the cell line Toll pathway and a variety of cellular physiological systems. Most notably, however, DENV infection down-regulated the expression levels of numerous immune signaling molecules and antimicrobial peptides (AMPs). Functional assays showed that transcriptional induction of AMPs from the Toll and IMD pathways in response to bacterial challenge is impaired in DENV-infected cells. In addition, Escherichia coli, a Gram-negative bacteria species, grew better when co-cultured with DENV-infected cells than with uninfected cells, suggesting a decreased production of AMPs from the IMD pathway in virus-infected cells. Pre-stimulation of the cell line with Gram-positive bacteria prior to DENV infection had no effect on DENV titers, while pre-stimulation with Gram-negative bacteria resulted in an increase in DENV titers. These results indicate that DENV is capable of actively suppressing immune responses in the cells it infects, a phenomenon that may have important consequences for virus transmission and insect physiology. PMID:20502529

Sim, Shuzhen; Dimopoulos, George

2010-01-01

26

Free flight of the mosquito Aedes aegypti  

E-print Network

High speed video observations of free flying male Aedes aegypti mosquitoes, the dengue and yellow fever vector, along with custom measurement methods, enable measurement of wingbeat frequency, body position and body orientation of mosquitoes during flight. We find these mosquitoes flap their wings at approximately 850 Hz. We also generate body yaw, body pitch and wing deviation measurements with standard deviations of less than 1 degree and find that sideways velocity and acceleration are important components of mosquito motion. Rapid turns involving changes in flight direction often involve large sideways accelerations. These do not correspond to commensurate changes in body heading, and the insect's flight direction and body heading are decoupled during flight. These findings call in to question the role of yaw control in mosquito flight. In addition, using orientation data, we find that sideways accelerations are well explained by roll-based rotation of the lift vector. In contrast, the insect's body pitch...

Iams, S M

2012-01-01

27

Development of a SYBR green I based RT-PCR assay for yellow fever virus: application in assessment of YFV infection in Aedes aegypti  

PubMed Central

Background Yellow Fever virus (YFV) is an important arboviral pathogen in much of sub-Saharan Africa and the tropical Americas. It is the prototype member of the genus Flavivirus and is transmitted primarily by Aedes (Stegomyia) mosquitoes. The incidence of human infections in endemic areas has risen in recent years. Prompt and dependable identification of YFV is a critical component of response to suspect cases. Results We developed a one-step SYBR Green I-based real-time quantitative RT-PCR (qRT-PCR) assay targeting the 5'NTR and capsid-gene junction--for rapid detection and quantification of YFV. The detection limit was 1 PFU/mL, 10-fold more sensitive than conventional RT-PCR, and there was no cross-reactivity with closely related flaviviruses or with alphaviruses. Viral load in samples was determined by standard curve plotted from cycle threshold (Ct) values and virus concentration. The efficacy of the assay in mosquitoes was assessed with spiked samples. The utility of the assay for screening of pooled mosquitoes was also confirmed. Replication of a Cameroon isolate of YFV in Ae. aegypti revealed a marked variation in susceptibility among different colonies at different days post infection (pi). Conclusions The SYBR Green-1 based qRT-PCR assay is a faster, simpler, more sensitive and less expensive procedure for detection and quantification of YFV than other currently used methods. PMID:22264275

2012-01-01

28

Repellent activity of selected essential oils against Aedes aegypti  

Microsoft Academic Search

Essential oils extracted from ten plant species were screened for repellency against Aedes aegypti mosquitoes. Three oils; Zanthoxylum piperitum, Anethum graveolens and Kaempferia galanga, exerted protection against A. aegypti, with median complete-protection times of 1, 0.5 and 0.25 h, respectively. The protection times were increased significantly by incorporating 10% vanillin. The highest potential was established from Z. piperitum oil +10% vanillin

W. Choochote; U. Chaithong; K. Kamsuk; A. Jitpakdi; P. Tippawangkosol; B. Tuetun; D. Champakaew; B. Pitasawat

2007-01-01

29

Breeding habitats of Aedes aegypti (L) and Aedes. albopictus (Skuse) in villages of Barru, South Sulawesi, Indonesia.  

PubMed

The breeding habitats of the dengue vector, Aedes aegypti and Aedes albopictus, were studied using larval collection method inside and outside houses in 6 villages of Barru, South Sulawesi, Indonesia from July 1994 to August 1995. Aedes aegypti was the dominant species, being abundant indoors especially in the coastal areas. Aedes albopictus was breeding primarily in outdoor containers in the hill and mountain areas. Earthen jar was the most common breeding habitat of Aedes aegypti in all villages surveyed. Drum can was the most common outdoor breeding habitat of Aedes albopictus in the hill and mountain areas. The high Breteau indices of Aedes aegypti and Aedes albopictus suggests that these species may play an important role in the transmission of dengue hemorrhagic fever in Barru where epidemics of the fever occur occasionally. PMID:9656413

Ishak, H; Miyagi, I; Toma, T; Kamimura, K

1997-12-01

30

Vector Competence in West African Aedes aegypti Is Flavivirus Species and Genotype Dependent  

PubMed Central

Background Vector competence of Aedes aegypti mosquitoes is a quantitative genetic trait that varies among geographic locations and among different flavivirus species and genotypes within species. The subspecies Ae. aegypti formosus, found mostly in sub-Saharan Africa, is considered to be refractory to both dengue (DENV) and yellow fever viruses (YFV) compared to the more globally distributed Ae. aegypti aegypti. Within Senegal, vector competence varies with collection site and DENV-2 viral isolate, but knowledge about the interaction of West African Ae. aegypti with different flaviviruses is lacking. The current study utilizes low passage isolates of dengue-2 (DENV-2-75505 sylvatic genotype) and yellow fever (YFV BA-55 -West African Genotype I, or YFV DAK 1279-West African Genotype II) from West Africa and field derived Ae. aegypti collected throughout Senegal to determine whether vector competence is flavivirus or virus genotype dependent. Methodology/Principal Findings Eight collections of 20–30 mosquitoes from different sites were fed a bloodmeal containing either DENV-2 or either isolate of YFV. Midgut and disseminated infection phenotypes were determined 14 days post infection. Collections varied significantly in the rate and intensity of midgut and disseminated infection among the three viruses. Conclusions/Significance Overall, vector competence was dependent upon both viral and vector strains. Importantly, contrary to previous studies, sylvatic collections of Ae. aegypti showed high levels of disseminated infection for local isolates of both DENV-2 and YFV. PMID:25275366

Dickson, Laura B.; Sanchez-Vargas, Irma; Sylla, Massamba; Fleming, Karen; Black, William C.

2014-01-01

31

Wolbachia-Associated Bacterial Protection in the Mosquito Aedes aegypti  

PubMed Central

Background Wolbachia infections confer protection for their insect hosts against a range of pathogens including bacteria, viruses, nematodes and the malaria parasite. A single mechanism that might explain this broad-based pathogen protection is immune priming, in which the presence of the symbiont upregulates the basal immune response, preparing the insect to defend against subsequent pathogen infection. A study that compared natural Wolbachia infections in Drosophila melanogaster with the mosquito vector Aedes aegypti artificially transinfected with the same strains has suggested that innate immune priming may only occur in recent host-Wolbachia associations. This same study also revealed that while immune priming may play a role in viral protection it cannot explain the entirety of the effect. Methodology/Findings Here we assess whether the level of innate immune priming induced by different Wolbachia strains in A. aegypti is correlated with the degree of protection conferred against bacterial pathogens. We show that Wolbachia strains wMel and wMelPop, currently being tested for field release for dengue biocontrol, differ in their protective abilities. The wMelPop strain provides stronger, more broad-based protection than wMel, and this is likely explained by both the higher induction of immune gene expression and the strain-specific activation of particular genes. We also show that Wolbachia densities themselves decline during pathogen infection, likely as a result of the immune induction. Conclusions/Significance This work shows a correlation between innate immune priming and bacterial protection phenotypes. The ability of the Toll pathway, melanisation and antimicrobial peptides to enhance viral protection or to provide the basis of malaria protection should be further explored in the context of this two-strain comparison. This work raises the questions of whether Wolbachia may improve the ability of wild mosquitoes to survive pathogen infection or alter the natural composition of gut flora, and thus have broader consequences for host fitness. PMID:23951381

Ye, Yixin H.; Woolfit, Megan; Rancès, Edwige; O'Neill, Scott L.; McGraw, Elizabeth A.

2013-01-01

32

[Aedes aegypti resistance to temefos in counties of Ceará State].  

PubMed

The susceptibility of Aedes aegypti to temefos was evaluated by means of samples of eggs and larvae from four large counties in the state of Ceará (Fortaleza, Barbalha, Juazeiro do Norte and Crato). The technique standardized by the World Health Organization for tests with larvicides was used. The CL50 of eight samples from populations of Aedes was determined, as were their respective resistance ratios, compared to the CL50 of the susceptible Rockefeller strain. All populations submitted to the experiment showed resistance to temefos, with resistance ratios varying between 8 and 16. Analysis of these results reinforces prior evidence regarding the dissemination of temefos resistance in different locations in the state, subjected to considerable pressure for control in recent decades. The larvicide may lose its effectiveness if an urgent attempt is not made to reestablish the susceptibility of Aedes aegypti in these areas, profoundly affecting control campaigns currently under way. PMID:16906249

Lima, Estelita Pereira; de Oliveira Filho, Alfredo Martins; de Oliveira Lima, José Wellington; Ramos Júnior, Alberto Novaes; de Góes Cavalcanti, Luciano Pamplona; Pontes, Ricardo José Soares

2006-01-01

33

Aedes FADD: A novel death domain-containing protein required for antibacterial immunity in the yellow fever mosquito, Aedes aegypti  

E-print Network

in the yellow fever mosquito, Aedes aegypti Dawn M. Cooper*,1 , Ciara M. Chamberlain 1 , Carl Lowenberger 1 September 2008 Keywords: Mosquito Aedes aegypti FADD adaptor Antibacterial immunity IMD signaling AMP research in mosquitoes, the regulation of the pathways required for AMP expression remains largely unknown

Lowenberger, Carl

34

Bdelloid rotifer, Philodina species in the breeding containers of Aedes aegypti and Aedes albopictus.  

PubMed

The vector mosquitoes of dengue and chikungunya fever, Aedes aegypti and Aedes albopictus have adapted to feed on humans and undergo larval and pupal development in natural and artificial freshwater collections. Although several studies reported, still, much information is required to understand the successful survival of Aedes mosquitoes in small temporary containers. In an investigation conducted in the chikungunya affected areas of Kerala state, India, the presence of Bdelloid rotifer, Philodina in 95% of breeding habitats of Ae. aegypti and Ae. albopictus was recorded. The role of Philodina in the breeding containers was investigated. It was found that while in control the number of Philodina was found increasing in the water sample during the study period of seven days, the number found decreased in the containers with larvae of Aedes. The gut content analysis also confirmed the presence of the rotating wheel, corona of Philodina in some of the specimen suggests its role as major larval food. PMID:23202612

Muniaraj, M; Arunachalam, N; Paramasivan, R; Mariappan, T; Philip Samuel, P; Rajamannar, V

2012-12-01

35

Insecticide susceptibility of Aedes aegypti and Aedes albopictus in Central Africa  

Microsoft Academic Search

Background  \\u000a Aedes aegypti (Linnaeus, 1762) and Aedes albopictus (Skuse, 1894) are the main vectors of dengue (DENV) and chikungunya (CHIKV) viruses worldwide. As there is still no vaccine\\u000a or specific treatment for DENV and CHIKV, vector control remains the cornerstone of prevention and outbreak control. Unfortunately,\\u000a vector control programs are facing operational challenges with mosquitoes becoming resistant to commonly used

Basile Kamgang; Sébastien Marcombe; Fabrice Chandre; Elysée Nchoutpouen; Philippe Nwane; Josiane Etang; Vincent Corbel; Christophe Paupy

2011-01-01

36

Transcriptome Analysis of Aedes aegypti Transgenic Mosquitoes with Altered Immunity  

PubMed Central

The mosquito immune system is involved in pathogen-elicited defense responses. The NF-?B factors REL1 and REL2 are downstream transcription activators of Toll and IMD immune pathways, respectively. We have used genome-wide microarray analyses to characterize fat-body-specific gene transcript repertoires activated by either REL1 or REL2 in two transgenic strains of the mosquito Aedes aegypti. Vitellogenin gene promoter was used in each transgenic strain to ectopically express either REL1 (REL1+) or REL2 (REL2+) in a sex, tissue, and stage specific manner. There was a significant change in the transcript abundance of 297 (79 up- and 218 down-regulated) and 299 (123 up- and 176 down-regulated) genes in fat bodies of REL1+ and REL2+, respectively. Over half of the induced genes had predicted functions in immunity, and a large group of these was co-regulated by REL1 and REL2. By generating a hybrid transgenic strain, which ectopically expresses both REL1 and REL2, we have shown a synergistic action of these NF-?B factors in activating immune genes. The REL1+ immune transcriptome showed a significant overlap with that of cactus (RNAi)-depleted mosquitoes (50%). In contrast, the REL2+ -regulated transcriptome differed from the relatively small group of gene transcripts regulated by RNAi depletion of a putative inhibitor of the IMD pathway, caspar (35 up- and 140 down-regulated), suggesting that caspar contributes to regulation of a subset of IMD-pathway controlled genes. Infections of the wild type Ae. aegypti with Plasmodium gallinaceum elicited the transcription of a distinct subset of immune genes (76 up- and 25 down-regulated) relative to that observed in REL1+ and REL2+ mosquitoes. Considerable overlap was observed between the fat body transcriptome of Plasmodium-infected mosquitoes and that of mosquitoes with transiently depleted PIAS, an inhibitor of the JAK-STAT pathway. PIAS gene silencing reduced Plasmodium proliferation in Ae. aegypti, indicating the involvement of the JAK-STAT pathway in anti-Plasmodium defense in this infection model. PMID:22114564

Xi, Zhiyong; Kokoza, Vladimir; Shin, Sang Woon; Dimopoulos, George; Raikhel, Alexander

2011-01-01

37

History of domestication and spread of Aedes aegypti - A Review  

PubMed Central

The adaptation of insect vectors of human diseases to breed in human habitats (domestication) is one of the most important phenomena in medical entomology. Considerable data are available on the vector mosquito Aedes aegypti in this regard and here we integrate the available information including genetics, behaviour, morphology, ecology and biogeography of the mosquito, with human history. We emphasise the tremendous amount of variation possessed by Ae. aegypti for virtually all traits considered. Typological thinking needs to be abandoned to reach a realistic and comprehensive understanding of this important vector of yellow fever, dengue and Chikungunya. PMID:24473798

Powell, Jeffrey R; Tabachnick, Walter J

2013-01-01

38

Field evaluations of disposable sticky lures for surveillance of Aedes aegypti (Stegomyia aegypti) and Culex quinquefasciatus in Jakarta.  

PubMed

From December 1997 to April 1998, disposable sticky lures (1608 lure days) were trialled in homes in north Jakarta, Indonesia as surveillance tools for Aedes aegypti (Stegomyia aegypti) (Diptera: Culicidae) and Culex quinquefasciatus (Diptera: Culicidae), referenced to indoor resting adult collections (92 × 10 min). The lures collected 89.4% of the total of 1339 Ae. aegypti and 92.1% of the total of 1272 Cx. quinquefasciatus collected by all methods. Because there were no significant differences with respect to numbers collected in bedrooms, living rooms and kitchens, bedrooms were selected for subsequent trials for reasons of convenience. The main trials involved a replicated complete block design with L-lysine and sodium carbonate. Lures without attractant or with four different dilutions of L-lysine collected 3.4-8.5 times more Ae. aegypti and 4.2-8.1 times more Cx. quinquefasciatus than were collected by mouth aspirator. Lures with or without dilutions of sodium carbonate collected 2.7-5.0 times more Ae. aegypti and 1.8-4.2 times more Cx. quinquefasciatus than aspirator collections. The precision associated with catches of sticky lures was better than that for aspirator collections. Although olfactants generally improved the numbers of mosquitoes collected, the differences in catch between lures with and without attractants were usually non-significant. Any deficit in catch may be offset by increasing the surveillance period to ?30 days to detect all four dengue serotypes from infected mosquitoes. PMID:23002913

Kay, B H; Brown, M D; Siti, Z; Bangs, M J

2013-09-01

39

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

PubMed Central

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 Malagasy populations. The experimental oral infection method showed that six Ae. albopictus populations exhibited high dissemination infection rates for chikungunya virus ranging from 98 to 100%. Conclusion In Madagascar, Ae. albopictus has extended its geographical distribution whereas, Ae. aegypti has become rare, contrasting with what was previously observed. Changes are predominantly driven by human activities and the rainfall regime that provide suitable breeding sites for the highly anthropophilic mosquito Ae. albopictus. Moreover, these populations were found to be highly susceptible to chikungunya virus. In the light of this study, Ae. albopictus may have been involved in the recent outbreaks of chikungunya and dengue epidemics in Madagascar, and consequently, control measures should be promoted to limit its current expansion. PMID:22433186

2012-01-01

40

The Fat Body Transcriptomes of the Yellow Fever Mosquito Aedes aegypti, Pre-and Post-Blood Meal  

E-print Network

The Fat Body Transcriptomes of the Yellow Fever Mosquito Aedes aegypti, Pre- and Post- Blood Meal Transcriptomes of the Yellow Fever Mosquito Aedes aegypti, Pre- and Post- Blood Meal. PLoS ONE 6(7): e22573. doi@nmsu.edu Introduction The yellow fever mosquito, Aedes aegypti, is the primary vector for dengue fever, several

Houde, Peter

41

Effect of Wolbachia on insecticide susceptibility in lines of Aedes aegypti.  

PubMed

Two stable infections of Wolbachia pipientis, wMelPop and wMel, now established in Aedes aegypti, are being used in a biocontrol program to suppress the transmission of dengue. Any effects of Wolbachia infection on insecticide resistance of mosquitoes may undermine the success of this program. Bioassays of Ae. aegypti were conducted to test for differences in response to insecticides between Wolbachia infected (wMelPop, wMel) and uninfected lines. Insecticides screened were bifenthrin, the pyrethroid commonly used for adult knockdown, as well as larvicides: Bacillus thuringiensis var. israelensis, the organophosphate, temephos and the insect growth regulator, s-methoprene. While differences in response between lines were detected for some insecticides, no obvious or consistent effects related to presence of Wolbachia infection were observed. Spreading Wolbachia infections are, therefore, unlikely to affect the efficacy of traditional chemical control of mosquito outbreaks. PMID:23149015

Endersby, N M; Hoffmann, A A

2013-06-01

42

Genome sequence of Aedes aegypti, a major arbovirus vector  

PubMed Central

We present a draft sequence of the genome of Aedes aegypti, the primary vector for yellow fever and dengue fever, which at ~1.38 Gbp is ~5-fold larger in size than the genome of the malaria vector, Anopheles gambiae. Nearly 50% of the Aedes aegypti genome consists of transposable elements. These contribute to a ~4-6 fold increase in average gene length and the size of intergenic regions relative to Anopheles gambiae and Drosophila melanogaster. Nevertheless, chromosomal synteny is generally maintained between all three insects although conservation of orthologous gene order is higher (~2-fold) between the mosquito species than between either of them and fruit fly. Three methods have provided transcriptional evidence for 80% of the 15,419 predicted protein coding genes in Aedes aegypti. An increase in genes encoding odorant binding, cytochrome P450 and cuticle domains relative to Anopheles gambiae suggests that members of these protein families underpin some of the biological differences between them. PMID:17510324

Sinkins, Sp

2010-01-01

43

Male accessory gland substances from Aedes albopictus affect the locomotor activity of Aedes aegypti females  

PubMed Central

Dengue is one of the world’s most important mosquito-borne diseases and is usually transmitted by one of two vector species: Aedes aegypti or Aedes albopictus . These two diurnal mosquitoes are frequently found coexisting in similar habitats, enabling interactions between adults, such as cross-mating. The objective of this study was to assess cross-mating between Ae. aegypti females and Ae. albopictus males under artificial conditions and evaluate the locomotor activity of Ae. aegypti virgin females injected with male accessory gland (MAG) homogenates to infer the physiological and behavioural responses to interspecific mating. After seven days of exposure, 3.3-16% of Ae. aegypti females mated with Ae. albopictus males. Virgin Ae. aegypti females injected with conspecific and heterospecific MAGs showed a general decrease in locomotor activity compared to controls and were refractory to mating with conspecific males. The reduction in diurnal locomotor activity induced by injections of conspecific or heterospecific MAGs is consistent with regulation of female reproductive activities by male substances, which are capable of sterilising female Ae. aegypti through satyrisation by Ae. albopictus . PMID:24473799

Lima-Camara, Tamara Nunes; Codeco, Claudia Torres; Honorio, Nildimar Alves; Bruno, Rafaela Vieira; Peixoto, Alexandre Afranio; Lounibos, Leon Philip

2013-01-01

44

Effects of Bacillus subtilis metabolites on larval Aedes aegypti L.  

PubMed

The culture supernatant of a strain of Bacillus subtilis isolated from soil samples killed larvae of the mosquito Aedes aegypti. The metabolites produced by B. subtilis were characterized using high performance liquid chromatography (HPLC). Mortality rate was dose-dependent for all larval instars of A. aegypti. Log probit analysis (95% confidence level) revealed an LC50 of 1.73 and an LC90 3.71?g/ml. Molecular weights/masses of B. subtilis metabolites were confirmed using SDS-PAGE analysis. B. subtilis metabolites were confirmed using HPLC analysis. We demonstrate that secondary metabolites from B. subtilis have larvicidal activity against A. aegypti and may be suitable for the control of this and other mosquito vectors of human disease. The larvae to the metabolites, significant reduction in the activities of acetylcholinesterse, ?-carboxylesterase, and acid phosphatases were recorded. PMID:24267699

Revathi, Kannan; Chandrasekaran, Rajamanickam; Thanigaivel, Annamalai; Kirubakaran, Suyambulingam Arunachalam; Sathish-Narayanan, Subbiah; Senthil-Nathan, Sengottayan

2013-11-01

45

Larvicidal activity of Tagetes erecta against Aedes aegypti.  

PubMed

The aim of this study was to evaluate the activity of essential oil from Tagetes erecta against 3rd instars of Aedes aegypti and to determine the amounts of larvicidal thiophenes in all plant tissues. The oil obtained by steam distillation and analyzed by gas chromatography/mass spectrometry showed 14 compounds. The main compounds were piperitone (45.72%), D-limonene (9.67%), and piperitenone (5.89%). The essential oil was active against larvae of Ae. aegypti, with LC50 of 79.78 microg/ml and LC90 of 100.84 microg/ml. The larvicidal thiophene contents were higher in the roots and flowers as demonstrated by high-performance liquid chromatography analysis. Thus, T. erecta constitutes a good source of varied compounds showing larvicidal activity against Ae. aegypti. PMID:21805850

Marques, Márcia M M; Morais, Selene M; Vieira, Icaro G P; Vieira, Mariano G S; Raquel, Ana; Silva, A; De Almeida, Raimundo Rafael; Guedes, Maria Izabel F

2011-06-01

46

Integrated proteomic and transcriptomic analysis of the Aedes aegypti eggshell  

PubMed Central

Background Mosquito eggshells show remarkable diversity in physical properties and structure consistent with adaptations to the wide variety of environments exploited by these insects. We applied proteomic, transcriptomic, and hybridization in situ techniques to identify gene products and pathways that participate in the assembly of the Aedes aegypti eggshell. Aedes aegypti population density is low during cold and dry seasons and increases immediately after rainfall. The survival of embryos through unfavorable periods is a key factor in the persistence of their populations. The work described here supports integrated vector control approaches that target eggshell formation and result in Ae. aegypti drought-intolerant phenotypes for public health initiatives directed to reduce mosquito-borne diseases. Results A total of 130 proteins were identified from the combined mass spectrometric analyses of eggshell preparations. Conclusions Classification of proteins according to their known and putative functions revealed the complexity of the eggshell structure. Three novel Ae. aegypti vitelline membrane proteins were discovered. Odorant-binding and cysteine-rich proteins that may be structural components of the eggshell were identified. Enzymes with peroxidase, laccase and phenoloxidase activities also were identified, and their likely involvements in cross-linking reactions that stabilize the eggshell structure are discussed. PMID:24707823

2014-01-01

47

Comparison of the insecticide susceptibilities of laboratory strains of Aedes aegypti and Aedes albopictus.  

PubMed

A susceptible strain of Aedes albopictus derived from the Gainesville strain (Florida, USA) was established in our laboratory. The larvicidal efficacies of the neurotoxic insecticides temephos, permethrin and the pure cis and trans-permethrin isomers and the microbial insecticide Bacillus thuringiensis israelensis (Bti) against Ae. albopictus were estimated and compared to a susceptible strain of Aedes aegypti. The larvicidal effect of insect growth regulator pyriproxyfen was also evaluated in both mosquito strains. The median lethal concentration/median emergency inhibition values for Ae. aegypti and Ae. albopictus, respectively, were: temephos, 3.058 and 6.632 ppb, permethrin, 3.143 and 4.933 ppb, cis-permethrin, 4.457 and 10.068 ppb, trans-permethrin, 1.510 and 3.883 ppb, Bti, 0.655 and 0.880 ppb and pyriproxyfen, 0.00774 and 0.01642 ppb. Ae. albopictus was more tolerant than Ae. aegypti to all six larvicides evaluated. The order of susceptibility for Ae. aegypti was pyriproxyfen > Bti > trans-permethrin > temephos > permethrin > cis-permethrin and for Ae. albopictus was pyriproxyfen > Bti > trans-permethrin > permethrin > temephos > cis-permethrin. Because both species can be found together in common urban, suburban and rural breeding sites, the results of this work provide baseline data on the susceptibility of Ae. albopictus to insecticides commonly used for controlling Ae. aegypti in the field. PMID:22241122

Gómez, Andrea; Seccacini, Emilia; Zerba, Eduardo; Licastro, Susana

2011-12-01

48

Neuropeptidomics of the mosquito Aedes aegypti  

PubMed Central

Neuropeptidomic data were collected on the mosquito Ae. aegypti which is considered the most tractable mosquito species for physiological and endocrine studies. The data were solely obtained by direct mass spectrometric profiling, including tandem fragmentation, of selected tissues from single specimens which yielded a largely complete accounting of the putative bioactive neuropeptides; truncated neuropeptides with low abundance were not counted as mature peptides. Differential processing within the CNS was detected for the CAPA-precursor and differential post-translational processing (pyroglutamate formation) was detected for AST-C and CAPA-PVK-2. For the first time in insects, we succeeded in the direct mass spectrometric profiling of midgut tissue which yielded a comprehensive and immediate overview of the peptides involved in the endocrine system of the gut. Head peptides which were earlier identified as the most abundant RFamides of Ae. aegypti, were not detected in any part of the CNS or midgut. This study provides a framework for future investigations on mosquito endocrinology and neurobiology. Given the high sequence similarity of neuropeptide precursors identified in other medically important mosquitoes, conclusions regarding the peptidome of Ae. aegypti likely are applicable to these mosquitoes. PMID:20163154

Predel, Reinhard; Neupert, Susanne; Garczynski, Stephen F.; Crim, Joe W.; Brown, Mark R.; Russell, William K.; Kahnt, Jörg; Russell, David H.; Nachman, Ronald J.

2010-01-01

49

Association of Human Immune Response to Aedes aegypti Salivary Proteins with Dengue Disease Severity  

PubMed Central

SUMMARY Dengue viruses (DENV; family Flaviviridae, genus Flavivirus) are transmitted by Aedes aegypti mosquitoes and can cause dengue fever (DF), a relatively benign disease, or more severe dengue haemorrhagic fever (DHF). Arthropod saliva contains proteins delivered into the bite wound that can modulate the host haemostatic and immune responses to facilitate the intake of a blood meal. The potential effects on DENV infection of previous exposure to Ae. aegypti salivary proteins have not been investigated. We collected Ae. aegypti saliva, concentrated the proteins, and fractionated them by non-denaturing polyacrylamide gel electrophoresis (PAGE). By use of immunoblots we analysed reactivity with the mosquito salivary proteins (MSP) of sera from 96 Thai children diagnosed with secondary DENV infections leading either to DF or DHF, or with no DENV infection, and found that different proportions of each patient group had serum antibodies reactive to specific Ae. aegypti salivary proteins. Our results suggest that prior exposure to MSP might play a role in the outcome of DENV infection in humans. PMID:21995849

Machain-Williams, Carlos; Mammen, Mammen P; Zeidner, Nordin S; Beaty, Barry J; Prenni, Jessica E.; Nisalak, Ananda

2011-01-01

50

Molecular characterization of the Aedes aegypti odorant receptor gene family  

PubMed Central

The olfactory-driven blood-feeding behaviour of female Aedes aegypti mosquitoes is the primary transmission mechanism by which the arboviruses causing dengue and yellow fevers affect over 40 million individuals worldwide. Bioinformatics analysis has been used to identify 131 putative odourant receptors from the A. aegypti genome that are likely to function in chemosensory perception in this mosquito. Comparison with the Anopheles gambiae olfactory subgenome demonstrates significant divergence of the odourant receptors that reflects a high degree of evolutionary activity potentially resulting from their critical roles during the mosquito life cycle. Expression analyses in the larval and adult olfactory chemosensory organs reveal that the ratio of odourant receptors to antennal glomeruli is not necessarily one to one in mosquitoes. PMID:17635615

Bohbot, J.; Pitts, R. J.; Kwon, H.-W.; Rützler, M.; Robertson, H. M.; Zwiebel, L. J.

2011-01-01

51

Toxicities of certain larvicides to resistant and susceptible Aedes aegypti  

PubMed Central

In a study of the toxicological characteristics of dieldrin-resistant and DDT-resistant strains of Aedes aegypti, combined with an evaluation of certain larvicides, 14 cyclodienes, 13 DDT-type compounds, 18 organophosphorus compounds, several carbamates and a number of other compounds were tested against larvae of A. aegypti. Telodrin and GC-9160 proved to be toxic against a highly dieldrin-resistant strain. Against highly DDT-resistant strains the toxicity of DDT could be enhanced by piperonyl butoxide, DMC or WARF, that of deutero-DDT by DMC, and that of methoxychlor by piperonyl butoxide. Prolan and Bulan were found to be slightly less effective than deutero-DDT against highly DDT-resistant strains. Among the more recent organophosphorus compounds found to exceed fenthion in toxicity are AC-52160, Stauffer N-2404, Folithion, Bayer 52957 and SD-7438. The effectiveness of dimethrin could be enhanced with piperonyl butoxide. PMID:5294255

Klassen, W.; Keppler, W. J.; Kitzmiller, J. B.

1965-01-01

52

Pyrethroid resistance in Aedes aegypti larvae (Diptera: Culicidae) from Singapore.  

PubMed

We report the first comprehensive insecticide susceptibility status ofAedes aegypti (L.) larvae from Singapore. The study indicated that Ae. aegypti is susceptible to temephos, although resistance (RR50 = 1.29-4.43-fold) couldbe developing. Of high concern is the detection of moderate to high resistance to permethrin (RR50 = 29-47-fold) and etofenprox (RR50 = 14-34-fold). Biolarvicide Bacillus thuringiensis israelensis (Bti) remains effective. The insecticide susceptibility profile of Ae. aegypti larvae was found to be homogenous among the different sites studied across the island city. The addition of synergists piperonyl butoxide, S,S,S,-tributyl phosphorotrithioate, and triphenyl phosphate generally failed to enhance the toxicity of the insecticides investigated, suggesting an insignificant role of metabolic-based resistance, and a possible involvement of target site resistance. Further biochemical investigation of specific metabolic enzyme activities suggested that detoxifying enzymes, mono-oxygenases, esterases, glutathione S-transferases, and altered acetylcholinesterases, generally did not contribute to the resistance observed. This study clearly demonstrated that pyrethroid resistance is widespread among Ae. aegypti population and lowered susceptibility to organophosphates is developing. PMID:24605467

Koou, Sin-Ying; Chong, Chee-Seng; Vythilingam, Indra; Ng, Lee-Ching; Lee, Chow-Yang

2014-01-01

53

Vector competence of Aedes aegypti (L.) and Culex quinquefasciatus (Say) for Dirofilaria immitis (Leidy).  

PubMed

This study was performed to examine the vector competence of Aedes aegypti and Culex quinquefasciatus for Dirofilaria immitis. Eleven individual experiments were conducted in this study. Nonthaburi and Udon Thani strains of Ae. aegypti were allowed to feed on infected dogs that had 5,750 and 4,600 microfilariae (mW) per ml of blood, respectively. Three groups of Bangkok-strain Cx. quinquefasciatus were allowed to feed on dogs that had 4,800, 5,200, and 5,850 mf per ml of blood. Six groups of Liverpool-strain Ae. aegypti were allowed to feed on dogs with 1,650, 1,950, 3,350, 9,000, 9,250, and 11,550 mf per ml of blood. Three to 4% of Nonthaburi-strain, and 0-6% of Udon Thani-strain Ae. aegypti became infected and had infective-stage larvae (L3) of D. immitis in their probosces. Zero to 1 and 7% of Bangkok-strain Cx. quinquefasciatus had L3 in their probosces after taking blood meals with 4,800 and 5,850 mf per ml of blood, respectively. The percent-infected Liverpool-strain Ae. aegypti with L3 in their probosces were 3-12, 0-12, 10, 16, 7-19, and 0-21 after taking blood meals with 1,650, 1,950, 3,350, 9,000, 9,250, and 11,550 mf per ml of blood, respectively, when tested at different post-blood-feeding days. This study showed both Ae. aegypti and Cx. quinquefasciatus from Thailand can become vectors for D. immitis; however, Liverpool-strain Ae. aegypti are more likely to be competent vectors for D. immitis than Ae. aegypti and Cx. quinquefasciatus from Thailand. The percent infection rates of Ae. aegypti and Cx. quinquefasciatus with D. immitis in the field in Thailand need to be investigated, to confirm the role of these mosquitoes in the life cycle of D. immitis in nature. PMID:17547063

Tiawsirisup, Sonthaya; Nithiuthai, Suwannee

2006-01-01

54

Insecticide susceptibility of the dengue vector, Aedes aegypti (L.) in Metropolitan Bangkok.  

PubMed

Mosquito larvae were collected from the houses of dengue infected patients in Bangkok, Thailand from 55 sites (36 out of the 50 districts of Metropolitan Bangkok). Aedes aegypti larvae were tested against temephos using WHO bioassay techniques. Adult mosquitoes were tested for susceptibility to permethrin, deltamethrin, cyfluthrin, malathion and DDT using WHO diagnostic doses. Most of the larvae tested were susceptible to temephos. Only few specimens were resistant to temephos. Most adult mosquitoes were highly susceptible to malathion. Deltamethrin resistance was seen in 6 districts of Bangkok. Variable levels of susceptibility were seen with cyfluthrin. Most of the specimens showed resistance to permethrin and all specimens were resistant to DDT. PMID:22299463

Komalamisra, Narumon; Srisawat, Raweewan; Phanbhuwong, Theerawit; Oatwaree, Sompis

2011-07-01

55

Functional Development of the Octenol Response in Aedes aegypti  

PubMed Central

Attraction of female Aedes aegypti mosquitoes to 1-octen-3-ol (octenol), CO2, lactic acid, or ammonia emitted by vertebrate hosts is not only contingent on the presence of odorants in the environment, but is also influenced by the insect’s physiological state. For anautogenous mosquito species, like A. aegypti, newly emerged adult females neither respond to host odors nor engage in blood-feeding; the bases for these behaviors are poorly understood. Here we investigated detection of two components of an attractant blend emitted by vertebrate hosts, octenol, and CO2, by female A. aegypti mosquitoes using electrophysiological, behavioral, and molecular approaches. An increase in sensitivity of octenol olfactory receptor neurons (ORNs) was correlated with an increase in odorant receptor gene (Or) expression and octenol-mediated attractive behavior from day 1 to day 6 post-emergence. While the sensitivity of octenol ORNs was maintained through day 10, behavioral responses to octenol decreased as did the ability of females to discriminate between octenol and octenol?+?CO2. Our results show differing age-related roles for the peripheral receptors for octenol and higher order neural processing in the behavior of female mosquitoes. PMID:23471139

Bohbot, Jonathan D.; Durand, Nicolas F.; Vinyard, Bryan T.; Dickens, Joseph C.

2013-01-01

56

Functional Development of the Octenol Response in Aedes aegypti.  

PubMed

Attraction of female Aedes aegypti mosquitoes to 1-octen-3-ol (octenol), CO2, lactic acid, or ammonia emitted by vertebrate hosts is not only contingent on the presence of odorants in the environment, but is also influenced by the insect's physiological state. For anautogenous mosquito species, like A. aegypti, newly emerged adult females neither respond to host odors nor engage in blood-feeding; the bases for these behaviors are poorly understood. Here we investigated detection of two components of an attractant blend emitted by vertebrate hosts, octenol, and CO2, by female A. aegypti mosquitoes using electrophysiological, behavioral, and molecular approaches. An increase in sensitivity of octenol olfactory receptor neurons (ORNs) was correlated with an increase in odorant receptor gene (Or) expression and octenol-mediated attractive behavior from day 1 to day 6 post-emergence. While the sensitivity of octenol ORNs was maintained through day 10, behavioral responses to octenol decreased as did the ability of females to discriminate between octenol and octenol?+?CO2. Our results show differing age-related roles for the peripheral receptors for octenol and higher order neural processing in the behavior of female mosquitoes. PMID:23471139

Bohbot, Jonathan D; Durand, Nicolas F; Vinyard, Bryan T; Dickens, Joseph C

2013-01-01

57

Organophosphate resistance in Trinidad and Tobago strains of Aedes aegypti.  

PubMed

Aedes aegypti larvae from 8 sites in Trinidad and 1 in Tobago were assayed against temephos, malathion, and fenthion using the Centers for Disease Control and Prevention time-mortality-based bioassay method. Resistance ratios (RRs) and resistance thresholds (RTs) for each insecticide were calculated in relation to the Caribbean Epidemiology Center reference susceptible strain. Results showed that the Haleland Park and Tobago strains were susceptible to fenthion and malathion, respectively (RRs < 1), while the San Fernando strain had a high RR (33.92) to malathion. All other strains had low-level resistance to fenthion and malathion. Resistance to temephos was more intense with 4 strains showing high-level resistance. The established RT was 60 min for fenthion, 75 min for bendiocarb, and 120 min for temephos and malathion. At the RTs, all Trinidad strains were resistant to temephos (11.50-74.50% mortality), 7 resistant to fenthion (21.25-78.75% mortality), and 5 resistant to malathion (56.25-77.50% mortality). The other strains were incipiently resistant (80-97% mortality). Despite the discrepancies between the RR levels and RT status, it is evident that the organophosphate insecticide resistance is prevalent in Trinidad and Tobago populations of Ae. aegypti. These results suggest that operational failure could soon occur and alternative strategies should be developed and implemented to reduce the probability of further selection pressure on resistant Ae. aegypti populations in Trinidad and Tobago. PMID:21290936

Polson, Karen A; Rawlins, Samuel C; Brogdon, William G; Chadee, Dave D

2010-12-01

58

The Sublethal Effects of the Entomopathic Fungus Leptolegnia chapmanii on Some Biological Parameters of the Dengue Vector Aedes aegypti  

PubMed Central

The mosquito Aedes aegypti (L.) (Diptera: Culicidae) is the primary vector of dengue in the Americas. The use of chemical insecticides is recommended during outbreaks of dengue in order to reduce the number of adult mosquitoes; however, because Ae. aegypti is highly synanthropic, the use of insecticides in densely populated areas is a dangerous practice. Leptolegnia chapmanii Seymour (Straminipila: Peronosporomycetes) is an entomopathogenic microorganism that has demonstrated marked pathogenicity toward the larvae of a number of mosquito species, with little or no effect on non-target insects. Therefore, the purpose of this study was to determine the sublethal effects of L. chapmanii on fecundity, number of gonotrophic cycles, fertility, and relationship between wing length and fecundity in Ae. aegypti females. Ae. aegypti females that survived infection with L. chapmanii laid fewer eggs, had a smaller number of gonotrophic cycles, had shorter wings, and were less fertile than controls. This is the first study on the sublethal effects experienced by specimens of Ae. aegypti that survived infection with zoospores of L. chapmanii. Although field studies should be carried out, the results obtained in this study are encouraging because the high and rapid larval mortality caused by L. chapmanii coupled with the reduction of reproductive capacity in Ae. aegypti females seem to cause a significant reduction in the number of adults in the mid and long term, thereby reducing the health risks associated with Ae. aegypti. PMID:23901823

Pelizza, S.A.; Scorsetti, A.C.; Tranchida, M.C.

2013-01-01

59

Vertebrate hosts of Aedes aegypti and Aedes mediovittatus (Diptera: Culicidae) in rural Puerto Rico.  

PubMed

The distribution of Aedes (Stegomyia) aegypti (L.), the main vector of dengue viruses (DENV) worldwide, overlaps with Aedes (Gymnometopa) mediovittatus (Coquillett), the Caribbean treehole mosquito, in urban, suburban, and rural areas. Ae. mediovittatus is a competent vector of DENV with high rates of vertical DENV transmission in the laboratory. This study determined whether Ae. mediovittatus feeds on humans and compared its feeding patterns with co-occurring Ae. aegypti in two rural communities of Puerto Rico. Adult mosquitoes were captured for three consecutive days every week from July 2009 to May 2010 using BG-Sentinel traps with skin lures that were placed in the front yard of houses in both communities. Three methods were used to identify the 756 bloodmeals obtained in this study: a multiplex polymerase chain reaction (PCR) for humans and dogs targeting cytochrome b; a PCR targeting the 16S rRNA; and a nested PCR targeting cytochrome b. Ae. mediovittatus fed mostly on humans (45-52%) and dogs (28-32%) but also on cats, cows, horses, rats, pigs, goats, sheep, and chickens. Ae. aegypti fed mostly on humans (76-79%) and dogs (18-21%) but also on cats, horses, and chickens. Our results indicate that Ae. mediovittatus may have a relatively high rate of vector-human contact, which might facilitate virus transmission or harborage in rural areas of Puerto Rico. PMID:22897052

Barrera, Roberto; Bingham, Andrea M; Hassan, Hassan K; Amador, Manuel; Mackay, Andrew J; Unnasch, Thomas R

2012-07-01

60

Cloning, sequencing and functional expression of an acetylcholinesterase gene from the yellow fever mosquito Aedes aegypti  

Microsoft Academic Search

A degenerate PCR strategy was used to isolate a fragment of the acetylcholinesterase gene (Ace) homolog from Aedes aegypti and screen for a cDNA clone containing the complete open reading frame of the gene. The predicted amino acid sequence of the Aedes gene shares 64% identify with Ace from Drosophila and 87% identity with the acetylcholinesterase gene from another mosquito

Nicola Anthony; Thomas Rocheleau; Giovani Mocelin; Hwa-Jung Lee; Richard ffrench-Constant

1995-01-01

61

Repellents Inhibit P450 Enzymes in Stegomyia (Aedes) aegypti  

PubMed Central

The primary defence against mosquitoes and other disease vectors is often the application of a repellent. Despite their common use, the mechanism(s) underlying the activity of repellents is not fully understood, with even the mode of action of DEET having been reported to be via different mechanisms; e.g. interference with olfactory receptor neurones or actively detected by olfactory receptor neurones on the antennae or maxillary palps. In this study, we discuss a novel mechanism for repellence, one of P450 inhibition. Thirteen essential oil extracts from Colombian plants were assayed for potency as P450 inhibitors, using a kinetic fluorometric assay, and for repellency using a modified World Health Organisation Pesticide Evaluations Scheme (WHOPES) arm-in cage assay with Stegomyia (Aedes) aegypti mosquitoes. Bootstrap analysis on the inhibition analysis revealed a significant correlation between P450-inhibition and repellent activity of the oils. PMID:23152795

Jaramillo Ramirez, Gloria Isabel; Logan, James G.; Loza-Reyes, Elisa; Stashenko, Elena; Moores, Graham D.

2012-01-01

62

Repellents inhibit P450 enzymes in Stegomyia (Aedes) aegypti.  

PubMed

The primary defence against mosquitoes and other disease vectors is often the application of a repellent. Despite their common use, the mechanism(s) underlying the activity of repellents is not fully understood, with even the mode of action of DEET having been reported to be via different mechanisms; e.g. interference with olfactory receptor neurones or actively detected by olfactory receptor neurones on the antennae or maxillary palps. In this study, we discuss a novel mechanism for repellence, one of P450 inhibition. Thirteen essential oil extracts from Colombian plants were assayed for potency as P450 inhibitors, using a kinetic fluorometric assay, and for repellency using a modified World Health Organisation Pesticide Evaluations Scheme (WHOPES) arm-in cage assay with Stegomyia (Aedes) aegypti mosquitoes. Bootstrap analysis on the inhibition analysis revealed a significant correlation between P450-inhibition and repellent activity of the oils. PMID:23152795

Jaramillo Ramirez, Gloria Isabel; Logan, James G; Loza-Reyes, Elisa; Stashenko, Elena; Moores, Graham D

2012-01-01

63

Pyrethroid Resistance in Aedes aegypti from Grand Cayman  

PubMed Central

The Grand Cayman population of Aedes aegypti is highly resistant to DDT and pyrethroid insecticides. Glutathione transferase, cytochrome P450, and esterase levels were increased in the Grand Cayman population relative to a susceptible laboratory strain, but synergist studies did not implicate elevated insecticide detoxification as a major cause of resistance. The role of target site resistance was therefore investigated. Two substitutions in the voltage-gated sodium channel were identified, V1016I in domain II, segment 6 (IIS6) (allele frequency = 0.79) and F1534C in IIIS6 (allele frequency = 0.68). The role of the F1534C mutation in conferring resistance to insecticides has not been previously established and so a tetraplex polymerase chain reaction assay was designed and used to genotype mosquitoes that had been exposed to insecticides. The F1534C mutation was strongly correlated with resistance to DDT and permethrin. PMID:20682868

Harris, Angela F.; Rajatileka, Shavanthi; Ranson, Hilary

2010-01-01

64

Origin of the Dengue Fever Mosquito, Aedes aegypti, in California  

PubMed Central

Dengue fever is among the most widespread vector-borne infectious diseases. The primary vector of dengue is the Aedes aegypti mosquito. Ae. aegypti is prevalent in the tropics and sub-tropics and is closely associated with human habitats outside its native range of Africa. While long established in the southeastern United States of America where dengue is re-emerging, breeding populations have never been reported from California until the summer of 2013. Using 12 highly variable microsatellite loci and a database of reference populations, we have determined that the likely source of the California introduction is the southeastern United States, ruling out introductions from abroad, from the geographically closer Arizona or northern Mexico populations, or an accidental release from a research laboratory. The power to identify the origin of new introductions of invasive vectors of human disease relies heavily on the availability of a panel of reference populations. Our work demonstrates the importance of generating extensive reference databases of genetically fingerprinted human-disease vector populations to aid public health efforts to prevent the introduction and spread of vector-borne diseases. PMID:25077804

Gloria-Soria, Andrea; Brown, Julia E.; Kramer, Vicki; Hardstone Yoshimizu, Melissa; Powell, Jeffrey R.

2014-01-01

65

Winter Refuge for Aedes aegypti and Ae. albopictus Mosquitoes in Hanoi during Winter  

PubMed Central

Dengue occurs throughout the year in Hanoi, Vietnam, despite winter low temperatures <10°C. During July 2010 to March 2012, we surveyed monthly for Aedes larvae and pupae in 120 houses in 8 Hanoi districts. Aedes albopictus preferred discarded containers in summer and pupal density drastically decreased in winter. Aedes aegypti preferred concrete tanks and this preference increased in winter. Even in winter, the lowest water temperature found in concrete tanks was >14°C, exceeding the developmental zero point of Ae. aegypti. Although jars, drums and concrete tanks were the dominant containers previously (1994–97) in Hanoi, currently the percentage of residences with concrete tanks was still high while jars and drums were quite low. Our study showed that concrete tanks with broken lids allowing mosquitoes access were important winter refuge for Ae. aegypti. We also indicate a concern about concrete tanks serving as foci for Ae. aegypti to expand their distribution in cooler regions. PMID:24752230

Tsunoda, Takashi; Cuong, Tran Chi; Dong, Tran Duc; Yen, Nguyen Thi; Le, Nguyen Hoang; Phong, Tran Vu; Minakawa, Noboru

2014-01-01

66

Adult survivorship of the dengue mosquito Aedes aegypti varies seasonally in central Vietnam.  

PubMed

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

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

2014-02-01

67

Mosquito Protein Kinase G Phosphorylates Flavivirus NS5 and Alters Flight Behavior in Aedes aegypti and Anopheles gambiae  

PubMed Central

Abstract Many arboviral proteins are phosphorylated in infected mammalian cells, but it is unknown if the same phosphorylation events occur when insects are similarly infected. One of the mammalian kinases responsible for phosphorylation, protein kinase G (PKG), has been implicated in the behavior of multiple nonvector insects, but is unstudied in mosquitoes. PKG from Aedes aegypti was cloned, and phosphorylation of specific viral sites was monitored by mass spectrometry from biochemical and cell culture experiments. PKG from Aedes mosquitoes is able to phosphorylate dengue nonstructural protein 5 (NS5) at specific sites in cell culture and cell-free systems and autophosphorylates its own regulatory domain in a cell-free system. Injecting Aedes aegypti and Anopheles gambiae mosquitoes with a pharmacological PKG activator resulted in increased Aedes wing activity during periods of their natural diurnal/crepuscular activity and increased Anopheles nocturnal locomotor/flight activity. Thus, perturbation of the PKG signaling pathway in mosquitoes alters flight behavior. The demonstrated effect of PKG alterations is consistent with a viral PKG substrate triggering increased PKG activity. This increased PKG activity could be the mechanism by which dengue virus increases flight behavior and possibly facilitates transmission. Whether or not PKG is part of the mechanism by which dengue increases flight behavior, this report is the first to show PKG can modulate behavior in hematophagous disease vectors. PMID:23930976

Keating, Julie A.; Bhattacharya, Dipankar; Rund, Samuel S.C.; Hoover, Spencer; Dasgupta, Ranjit; Lee, Samuel J.; Duffield, Giles E.

2013-01-01

68

Climate change and the potential global distribution of Aedes aegypti: spatial modelling using GIS and CLIMEX.  

PubMed

We examined the potential added risk posed by global climate change on the dengue vector Aedes aegypti abundance using CLIMEX, a powerful tool for exploring the relationship between the fundamental and realised niche of any species. After calibrating the model using data from several knowledge domains, including geographical distribution records, we estimated potential distributions of the mosquito under current and future potential scenarios. The impact of climate change on its potential distribution was assessed with two global climate models, the CSIRO-Mk3.0 and the MIROC-H, run with two potential, future emission scenarios (A1B and A2) published by the Intergovernmental Panel on Climate Change. We compared today's climate situation with two arbitrarily chosen future time points (2030 and 2070) to see the impact on the worldwide distribution of A. aegypti . The model for the current global climate indicated favourable areas for the mosquito within its known distribution in tropical and subtropical areas. However, even if much of the tropics and subtropics will continue to be suitable, the climatically favourable areas for A. aegypti globally are projected to contract under the future scenarios produced by these models, while currently unfavourable areas, such as inland Australia, the Arabian Peninsula, southern Iran and some parts of North America may become climatically favourable for this mosquito species. The climate models for the Aedes dengue vector presented here should be useful for management purposes as they can be adapted for decision/making regarding allocation of resources for dengue risk toward areas where risk infection remains and away from areas where climatic suitability is likely to decrease in the future. PMID:24893017

Khormi, Hassan M; Kumar, Lalit

2014-05-01

69

CAGE TRIALS USING AN ENDOGENOUS MEIOTIC DRIVE GENE IN THE MOSQUITO AEDES AEGYPTI TO PROMOTE POPULATION REPLACEMENT  

E-print Network

CAGE TRIALS USING AN ENDOGENOUS MEIOTIC DRIVE GENE IN THE MOSQUITO AEDES AEGYPTI TO PROMOTE potential, and have previously been reported in two mosquito species: Aedes aegypti and Culex pipiens established three experimental population types that were initiated with 100%, 10%, and 1% male mosquitoes

Severson, David

70

Behavioral Responses of Catnip (Nepeta cataria) by Two Species of Mosquitoes, Aedes aegypti and Anopheles harrisoni, in Thailand  

Microsoft Academic Search

An investigation of the biological effect of catnip oil (Nepeta cataria L.) on the behavioral response of field collected Aedes aegypti and Anopheles harrisoni was conducted using an automated excito- repellency test system. Aedes aegypti showed significantly higher escape rates from the contact chamber at 5% catnip oil compared to other concentrations (P , 0.05). With Anopheles harrisoni, a high

Suppaluck Polsomboon; John P. Grieco; Nicole L. Achee; Kamlesh R. Chauhan; Somchai Tanasinchayakul; Jinrapa Pothikasikorn; Theeraphap Chareonviriyaphap

2008-01-01

71

Resistance of Aedes aegypti to temephos and adaptive disadvantages.  

PubMed

OBJECTIVE To evaluate the resistance of Aedes aegypti to temephos Fersol 1G (temephos 1% w/w) associated with the adaptive disadvantage of insect populations in the absence of selection pressure. METHODS A diagnostic dose of 0.28 mg a.i./L and doses between 0.28 mg a.i./L and 1.40 mg a.i./L were used. Vector populations collected between 2007 and 2008 in the city of Campina Grande, state of Paraíba, were evaluated. To evaluate competition in the absence of selection pressure, insect populations with initial frequencies of 20.0%, 40.0%, 60.0%, and 80.0% resistant individuals were produced and subjected to the diagnostic dose for two months. Evaluation of the development of aquatic and adult stages allowed comparison of the life cycles in susceptible and resistant populations and construction of fertility life tables. RESULTS No mortality was observed in Ae. aegypti populations subjected to the diagnostic dose of 0.28 mg a.i./L. The decreased mortality observed in populations containing 20.0%, 40.0%, 60.0%, and 80.0% resistant insects indicates that temephos resistance is unstable in the absence of selection pressure. A comparison of the life cycles indicated differences in the duration and viability of the larval phase, but no differences were observed in embryo development, sex ratio, adult longevity, and number of eggs per female. CONCLUSIONS The fertility life table results indicated that some populations had reproductive disadvantages compared with the susceptible population in the absence of selection pressure, indicating the presence of a fitness cost in populations resistant to temephos. PMID:25372168

Diniz, Morgana Michele Cavalcanti de Souza Leal; Henriques, Alleksandra Dias da Silva; Leandro, Renata da Silva; Aguiar, Dalvanice Leal; Beserra, Eduardo Barbosa

2014-10-01

72

IPB7 transposase behavior in Drosophila melanogaster and Aedes aegypti.  

PubMed

Transposons are used in insect science as genetic tools that enable the transformation of insects and the identification and isolation of genes though their ability to insert in or near to them. Four transposons, piggyBac, Mos1, Hermes and Minos are commonly used in insects beyond Drosophila melanogaster with piggyBac, due to its wide host range and frequency of transposition, being the most commonly chosen. The utility of these transposons as genetic tools is directly proportional to their activity since higher transposition rates would be expected to lead to higher transformation frequencies and higher frequencies of insertion throughout the genome. As a consequence there is an ongoing need for hyperactive transposases for use in insect genetics, however these have proven difficult to obtain. IPB7 is a hyperactive mutant of the piggyBac transposase that was identified by a genetic screen performed in yeast, a mammalian codon optimized version of which was then found to be highly active in rodent embryonic stem cells with no apparent deleterious effects. Here we report the activity of IPB7 in D. melanogaster and the mosquito, Aedes aegypti. Somatic transposition assays revealed an increase in IPB7's transposition rate from wild-type piggyBac transposase in D. melanogaster but not Ae. aegypti. However the use of IPB7 in D. melanogaster genetic transformations produced a high rate of sterility and a low transformation rate compared to wild-type transposase. This high rate of sterility was accompanied by significant gonadal atrophy that was also observed in the absence of the piggyBac vector transposon. We conclude that IPB7 has increased activity in the D. melanogaster germ-line but that a component of the sterility associated with its activity is independent of the presence of the piggyBac transposon. PMID:23835045

Wright, Jennifer A; Smith, Ryan C; Li, Xianghong; Craig, Nancy L; Atkinson, Peter W

2013-10-01

73

IPB7 transposase behavior in Drosophila melanogaster and Aedes aegypti  

PubMed Central

Transposons are used in insect science as genetic tools that enable the transformation of insects and the identification and isolation of genes though their ability to insert in or near to them. Four transposons, piggyBac, Mos1, Hermes and Minos are commonly used in insects beyond Drosophila melanogaster with piggyBac, due to its wide host range and frequency of transposition, being the most commonly chosen. The utility of these transposons as genetic tools is directly proportional to their activity since higher transposition rates would be expected to lead to higher transformation frequencies and higher frequencies of insertion throughout the genome. As a consequence there is an ongoing need for hyperactive transposases for use in insect genetics, however these have proven difficult to obtain. IPB7 is a hyperactive mutant of the piggyBac transposase that was identified by a genetic screen performed in yeast, a mammalian codon optimized version of which was then found to be highly active in rodent embryonic stem cells with no apparent deleterious effects. Here we report the activity of IPB7 in D. melanogaster and the mosquito, Aedes aegypti. Somatic transposition assays revealed an increase in IPB7’s transposition rate from wild-type piggyBac transposase in D. melanogaster but not Ae. aegypti. However the use of IPB7 in D. melanogaster genetic transformations produced a high rate of sterility and a low transformation rate compared to wild-type transposase. This high rate of sterility was accompanied by significant gonadal atrophy that was also observed in the absence of the piggyBac vector transposon. We conclude that IPB7 has increased activity in the D. melanogaster germ-line but that a component of the sterility associated with its activity is independent of the presence of the piggyBac transposon. PMID:23835045

Wright, Jennifer A.; Smith, Ryan C.; Xie, Kefong; Craig, Nancy L.; Atkinson, Peter W.

2013-01-01

74

Validation of Aedes aegypti Aag-2 cells as a model for insect immune studies  

PubMed Central

Background The understanding of mosquito immune responses can provide valuable tools for development of novel mosquito control strategies. Aiming the study at insect innate immunity, continuous insect cell lines have been established and used as research tools due to the fact that they constitute more homogeneous, sensitive, and reproducible systems than the insects from which they originated. More recently, Aag-2, an Aedes aegypti cell lineage, began to be frequently used as a model for studies of mosquito immunity. Nevertheless, to our knowledge, no study has systematically characterized the responses of Aag-2 cell line against different kinds of pathogens and compared its response to those exhibited by whole mosquitoes. For this reason, in this study we characterized gene expression profiles of the Aag-2 cell line in response to different kinds of immune challenges, such as Gram negative and positive bacteria, fungi and viruses, comparing the obtained results with the ones already described in the literature for whole mosquitoes. Methods Aedes aegypti Aag-2 cells were exposed to different immune stimuli (gram-positive and gram negative heat inactivated bacteria, zymosan or Sindbis virus) for 24 hours and the expression of selected marker genes from toll, IMD and Jak/STAT pathways was analyzed by qPCR. Also, cells were incubated with fluorescent latex beads for evaluation of its phagocytosis capacity. Results Aag-2 cells were stimulated with two concentrations of heat-killed Gram negative (Enterobacter cloacae) or Gram positive (Micrococcus luteus) bacteria, Zymosan or infected with Sindbis virus and the expression of key genes from the main immune related pathways, Toll, IMD and Jak/STAT, were investigated. Our results suggest that Toll and IMD pathways are activated in response to both Gram positive and negative bacteria and Zymosan in Aag-2 cells, displaying an immune profile similar to those described in the literature for whole mosquitoes. The same stimuli were also capable of activating Jak/STAT pathway in Aag-2 cells. Infection with Sindbis virus led to an up-regulation of the transcription factor STAT but was not able to induce the expression of any other gene from any of the pathways assayed. We also showed that this cell line is able to phagocytose latex beads in culture. Conclusions Our results characterize the expression profile of Aag-2 cells in response to different immune stimuli and demonstrate that this cell lineage is immune-competent and closely resembles the response described for whole Ae. aegypti mosquitoes. Hence, our findings support the use of Aag-2 as a tool to comprehend Ae. aegypti immune response both at cellular and humoral levels. PMID:22827926

2012-01-01

75

Isolation of midgut escape mutants of two American genotype dengue 2 viruses from Aedes aegypti  

PubMed Central

Background Several studies have shown that American genotype dengue 2 viruses (DENV2) have reduced viral fitness in the mosquito vector, Aedes aegypti, compared to other DENV2 genotypes. Diminished replication efficiency or inability to efficiently traverse membrane barriers encompassing organs such as the midgut or salivary glands are considered major factors negatively impacting viral fitness in the mosquito. Results We analyzed the vector competence of Ae. aegypti for two American DENV2 strains, QR94 and PR159 originating from Mexico and Puerto-Rico, respectively. Both strains infected mosquito midguts following acquisition of infectious bloodmeals. However, DENV2-QR94 and DENV2-PR159 poorly disseminated from the midgut at 7 or 14 days post-bloodmeal (pbm). We detected one virus isolate, EM33, among 31 DENV2-QR94 infected mosquitoes, and one isolate, EM41, among 121 DENV2-PR159 infected mosquitoes, generating high virus titers in mosquito carcasses at 7 days pbm. In oral challenge experiments, EM33 and EM41 showed midgut dissemination rates of 40-50%. Replication efficiency of EM41 in secondary mosquito tissue was similar to that of a dissemination-competent control strain, whereas the replication efficiency of EM33 was significantly lower than that of the control virus. The genome sequence of DENV2-QR94 encoded seven unique amino acids (aa), which were not found in 100 of the most closely related DENV2 strains. EM33 had one additional aa change, E202K, in the E protein. DENV2-PR159 encoded four unique aa residues, one of them E202K, whereas EM41 had two additional aa substitutions, Q77E in the E protein and E93D in NS3. Conclusions Our results indicate that the midgut of Ae. aegypti acts as a selective sieve for DENV2 in which genetically distinct, dissemination-competent virus variants are rapidly selected from the viral quasispecies to be transmitted to vertebrates. PMID:23937713

2013-01-01

76

Aedes aegypti from temperate regions of South America are highly competent to transmit dengue virus  

PubMed Central

Background Aedes aegypti is extensively spread throughout South America where it has been responsible for large dengue epidemics during the last decades. Intriguingly, dengue transmission has not been reported in Uruguay and is essentially prevalent in subtropical northern Argentina which borders Uruguay. Methods We assessed vector competence for dengue virus (DENV) of Ae. aegypti populations collected in subtropical Argentina (Corrientes) as well as temperate Uruguay (Salto) and Argentina (Buenos Aires) in 2012 using experimental oral infections with DENV-2. Mosquitoes were incubated at 28°C and examined at 14 and 21 days p.i. to access viral dissemination and transmission. Batches of the Buenos Aires mosquitoes were also incubated at 15°C and 20°C. Results Although mosquitoes from temperate Uruguay and Argentina were competent to transmit DENV, those from subtropical Argentina were more susceptible, displaying the highest virus titters in the head and presenting the highest dissemination of infection and transmission efficiency rates when incubated at 28°C. Interestingly, infectious viral particles could be detected in saliva of mosquitoes from Buenos Aires exposed to 15°C and 20°C. Conclusions There is a potential risk of establishing DENV transmission in Uruguay and for the spread of dengue outbreaks to other parts of subtropical and temperate Argentina, notably during spring and summer periods. PMID:24373423

2013-01-01

77

Bioactivity of selected plant essential oils against the yellow fever mosquito Aedes aegypti larvae  

Microsoft Academic Search

The bioactivity of 14 essential oils from five plants has been studied using the brine shrimp lethality test and the Aedes aegypti larvicidal assay. All essential oils screened had LC50 values smaller than 200 ?g\\/ml, showing significant lethality against brine shrimp. In addition, nine of the 14 essential oils tested showed toxicity against the fourth-instar A. aegypti larvae in 24

Sen-Sung Cheng; Hui-Ting Chang; Shang-Tzen Chang; Kun-Hsien Tsai; Wei-June Chen

2003-01-01

78

DAILY SURVIVAL RATES AND DISPERSAL OF AEDES AEGYPTI FEMALES IN RIO DE JANEIRO BRAZIL  

Microsoft Academic Search

Abstract. Daily survival rates, life expectancy, dispersal, and parity are important components of vectorial capacity of Aedes aegypti. These parameters,were estimated,for mosquito,populations,from a slum and a suburban,district in Rio de Janeiro, during the wet and dry seasons in 2005. In each mark-release-recapture experiment, three cohorts of dust-marked Ae. aegypti females were released. Recaptures were carried out daily in randomly selected

Rafael Maciel-de-freitas; Claudia Torres Codeço; Ricardo Lourenço-de-oliveira

79

DAILY SURVIVAL RATES AND DISPERSAL OF AEDES AEGYPTI FEMALES IN RIO DE JANEIRO, BRAZIL  

Microsoft Academic Search

Daily survival rates, life expectancy, dispersal, and parity are important components of vectorial capacity ofAedes aegypti. These parameters were estimated for mosquito populations from a slum and a suburban district in Rio de Janeiro, during the wet and dry seasons in 2005. In each mark-release-recapture experiment, three cohorts of dust-marked Ae. aegypti females were released. Recaptures were carried out daily

RAFAEL MACIEL-DE-FREITAS; RICARDO LOUREN; Rio de Janiero

80

The use of dragonfly nymphs in the control of Aedes aegypti.  

PubMed

The predatory rates of the dragonfly nymphs on Aedes aegypti were studied in the laboratory and under field conditons. Labellulid nymphs were found to predate on Ae. aegypti larvae and pupae readily. The rate of consumption was found to be 133 +/- 21 all stages of larvae per medium size nymph per 24 hours. In container habitats complete elimination of all larvae and pupae were achieved between day 4 and 9 depending on density of aquatic stages. The dragonfly nymphs as predators could be used in biological control of Aedes mosquitoes. PMID:6447358

Sebastian, A; Thu, M M; Kyaw, M; Sein, M M

1980-03-01

81

Diversity of containers and buildings infested with Aedes aegypti in Puerto Iguazú, Argentina.  

PubMed

Aedes aegypti is the main domestic vector of the dengue virus. Control measures to prevent dengue transmission focus on the treatment and elimination of this vector's oviposition sites. There is limited biological information on Ae. aegypti in Argentina. The aim of this study was to characterize Ae. aegypti oviposition sites in the city of Puerto Iguazú, Argentina. We surveyed an area covering nine neighborhoods in 2005. We identified 191 premises as positive for Ae. aegypti, giving a general house index of 9.6%. Premises classified as residential and vacant lots presented the highest number of infested premises, with 9% and 22% respectively. The total number of surveyed containers was 29,600. The overall container index (CI) was 1.1. The most frequently infested containers were water tanks (CI = 37). These preliminary results suggest that vacant lots and water tanks provide suitable breeding areas and environmental conditions, improving the chances of Ae. aegypti survival in Puerto Iguazú. PMID:23033195

Costa, Federico; Fattore, Gladys; Abril, Marcelo

2012-09-01

82

Bioefficacy of crude extract of Cyperus aromaticus (Family: Cyperaceae ) cultured cells, against Aedes aegypti and Aedes albopictus mosquitoes  

PubMed Central

Objective To evaluate the growth inhibition activity of the crude extract of Cyperus aromaticus (C. aromaticus) cultured cells against the 3rd instar larvae of Aedes aegypti (Linn.) and Aedes albopictus Skuse (Ae. albopictus) under laboratory conditions, and determine the sublethal effects (EI50) of the crude extract of C. aromaticus cultured cells on some biological and morphological parameters of both Aedes mosquito species during two generations as well. Methods The cell suspension cultures of C. aromaticus were activated from five callus lines (P4, Pa, Z1, Z6 and Ml) derived from the root explants of in vitro plantlets. The cultured cells were extracted in chloroform and used as plant material for the present study. For detection of juvenile hormone III, the crude extracts were analyzed by HPLC. Then the crude extracts of the three C. aromaticus cultured cell lines which contained varied amounts of juvenile hormone III [high level (P4 cell line), medium level (Z1 cell line) and low level (Ml cell line)] were tested against Aedes mosquito species. Laboratory evaluation was performed against late third instar larvae of the Vector Control Research Unit strains of Ae. aegypti and Ae. albopictus using the standard WHO method. The effects of EI50 of the C. aromaticus cultured P4 cells on fecundity, fertility, growth period, sex ratio, adult size and longevity of Aedes mosquitoes were assessed. Results Bioassay tests presented the remarkable growth inhibition activity of the crude extracts of C. aromaticus cultured cells against the two Aedes mosquitoes. Between the two mosquito species, Ae. albopictus was more susceptible to the crude extracts with lower EI50 values. EI50 of the crude extract of C. aromaticus cultured cells (P4) increased the sterility indices in the parental generation females in both Aedes mosquito species. A significant delay in the pupal formation and adult emergence were observed in the parental generation of the both mosquito species. The sex ratio of the adult population either parental or F1 generation of the Aedes mosquito species was not significantly affected by the EI50 dosage of the crude extract of C. aromaticus cultured P4 cells. A significant decrease in the wing length of the treated adult (female and male) of Aedes aegypti as well as the treated female of Ae. albopictus were observed. Longevity of the adult female of the parental generation of both Aedes mosquitoes as well as females of F1 generation of Ae. albopictus were significantly decreased. Conclusions The present study revealed the potential of the crude extract of C. aromaticus cultured cells in controlling vector mosquito populations in the effort to reduce the transmission of vector borne diseases. PMID:24075340

Kamiabi, Fatemeh; Jaal, Zairi; Keng, Chan Lai

2013-01-01

83

Functional and Genetic Characterization of Neuropeptide Y-Like Receptors in Aedes aegypti  

PubMed Central

Background Female Aedes aegypti mosquitoes are the principal vector for dengue fever, causing 50–100 million infections per year, transmitted between human and mosquito by blood feeding. Ae. aegypti host-seeking behavior is known to be inhibited for three days following a blood meal by a hemolymph-borne humoral factor. Head Peptide-I is a candidate peptide mediating this suppression, but the mechanism by which this peptide alters mosquito behavior and the receptor through which it signals are unknown. Methodology/Principal Findings Head Peptide-I shows sequence similarity to short Neuropeptide-F peptides (sNPFs) that have been implicated in feeding behaviors and are known to signal through Neuropeptide Y (NPY)-Like Receptors (NPYLRs). We identified eight NPYLRs in the Ae. aegypti genome and screened each in a cell-based calcium imaging assay for sensitivity against a panel of peptides. Four of the Ae. aegypti NPYLRs responded to one or more peptide ligands, but only NYPLR1 responded to Head Peptide-I as well as sNPFs. Two NPYLR1 homologues identified in the genome of the Lyme disease vector, Ixodes scapularis, were also sensitive to Head Peptide-I. Injection of synthetic Head Peptide-I and sNPF-3 inhibited host-seeking behavior in non-blood-fed female mosquitoes, whereas control injections of buffer or inactive Head Peptide-I [Cys10] had no effect. To ask if NPYLR1 is necessary for blood-feeding-induced host-seeking inhibition, we used zinc-finger nucleases to generate five independent npylr1 null mutant strains and tested them for behavioral abnormalities. npylr1 mutants displayed normal behavior in locomotion, egg laying, sugar feeding, blood feeding, host seeking, and inhibition of host seeking after a blood meal. Conclusions In this work we deorphanized four Ae. aegypti NPYLRs and identified NPYLR1 as a candidate sNPF receptor that is also sensitive to Head Peptide-I. Yet npylr1 alone is not required for host-seeking inhibition and we conclude that other receptors, additional peptides, or both, regulate this important behavior. PMID:24130914

Liesch, Jeff; Bellani, Lindsay L.; Vosshall, Leslie B.

2013-01-01

84

Post-Integration stability of piggyBac in Aedes aegypti  

PubMed Central

The post-integration activity of piggyBac transposable element gene vectors in Aedes aegypti mosquitoes was tested under a variety of conditions. The embryos from five independent transgenic lines of Aedes aegypti, each with a single integrated non-autonomous piggyBac transposable element gene vector, were injected with plasmids containing the piggyBac transposase open-reading frame under the regulatory control of the Drosophila melanogaster hsp70 promoter. No evidence for somatic remobilization was detected in the subsequent adults whereas somatic remobilization was readily detected when similar lines of transgenic Drosophila melanogaster were injected with the same piggyBac transposase-expressing plasmid. Aedes aegypti heterozygotes of piggyBac reporter-containing transgenes and piggyBac transposase-expressing transgenes showed no evidence of somatic and germ-line remobilization based on phenotypic and molecular detection methods. The post-integration mobility properties of piggyBac in Aedes aegypti enhance the utility of this gene vector for certain applications, particularly those where any level of vector remobilization is unacceptable. PMID:17681233

Sethuraman, Nagaraja; Fraser, Malcolm J.; Eggleston, Paul; O'Brochta, David. A

2008-01-01

85

Efficacy of botanical extracts from Callitris glaucophylla, against Aedes aegypti and Culex annulirostris mosquitoes  

Microsoft Academic Search

Using standard WHO methodology, this study investigated the susceptibility of 4th instar Aedes aegypti (L) and Culex annulirostris (Skuse) larvae to three extracts from Callitris glaucophylla (J. Thompson & L. Johnson) (1: steam distillation extract, 2: liquefied refrigerant gas extract, and 3: methanol reflux extract), lambda-cyhalothrin (a synthetic pyrethroid insecticide) and fenitrothion (an organophosphorous insecticide). Cx. annulirostris was significantly more

Essam Abdel-Salam Shaalan; Deon Vahid Canyon; Bruce Bowden; Mohamed Wagdy; Faried Younes; Hoda Abdel-Wahab; Abdel-Hamid Mansour

2006-01-01

86

Pollution by conspecifics as a component of intraspecific competition among Aedes aegypti larvae  

E-print Network

Pollution by conspecifics as a component of intraspecific competition among Aedes aegypti larvae, Montpellier, France Abstract. 1. The role of pollution by conspecifics in the costs associated with larval the effects of other processes to be expressed. 3. A cost of growing in polluted water was found: this cost

87

Sensitivity of Aedes aegypti adults (Diptera: Culicidae) to the vapors of Eucalyptus essential oils  

Microsoft Academic Search

Vapors of essential oils extracted from various species of Eucalyptus (E. gunnii, E. tereticornis, E. grandis, E. camaldulensis, E. dunnii, E. cinerea, E. saligna, E. sideroxylon, E. globulus ssp. globulus, E. globulus ssp. maidenii, E. viminalis and the hybrids E. grandis×E. tereticornis and E. grandis×E. camaldulensis) and their major components were found to be toxic to Aedes aegypti adults, the

Alejandro Lucia; Susana Licastro; Eduardo Zerba; Paola Gonzalez Audino; Hector Masuh

2009-01-01

88

Aedes aegypti in Brazil: genetically differentiated populations with high susceptibility to dengue and yellow fever viruses  

Microsoft Academic Search

Aedes aegypti was eliminated from Brazil in 1955, but re-infested the country in the 1970s. Dengue outbreaks have occurred since 1981 and became endemic in several cities in Brazil after 1986. Urban yellow fever has not occurred since 1942, and only jungle yellow fever cases have been reported. A population genetic analysis using isoenzyme variation combined with an evaluation of

R Lourenço-de-Oliveira; M Vazeille; A. M. B de Filippis; A. B Failloux

2004-01-01

89

Insulin stimulates ecdysteroid production through a conserved signaling cascade in the mosquito Aedes aegypti  

Microsoft Academic Search

Selective activators and inhibitors of insulin signaling cascades in mammalian cells were tested for their effects on insulin stimulated steroidogenesis by ovaries of Aedes aegypti. Bovine insulin in the concentration range of 1.7 ?M to 85 ?M stimulated ecdysteroidogenesis in vitro. Pervanadate, an inhibitor of tyrosine kinase phosphatase, stimulated ecdysteroid production at concentrations of 250 ?M to 1 mM. Okidaic

Michael A Riehle; Mark R Brown

1999-01-01

90

Environmental Conditions in Water Storage Drums and Influences on Aedes aegypti inTrinidad, West Indies  

PubMed Central

Water storage drums are often a primary breeding site for Aedes aegypti in developing countries. Habitat characteristics can impact both adult and larval fitness and survival, which may potentially influence arbovirus transmission. Our objective was to compare fundamental environmental differences in water drums based on the presence or absence of larvae in Trinidad. Drums were categorized according to the larval status, and if the drum was constructed of steel or plastic. Water samples were analyzed for ammonium, nitrate, and soluble reactive phosphorus (SRP). Continuous surface water temperatures were also recorded. Nutrient concentrations were considerably lower than those reported for other container breeding mosquitoes. No nutrient measured differed in concentration between drums positive compared to those that were negative for the presence of Aedes aegypti larvae. Levels of SRP and ammonium in steel drums were significantly lower than in plastic water drums. Both maximum and minimum surface temperatures were significantly lower in drums positive for the presence of larvae than in drums without larvae. Water temperatures in March and May were warmer than during October sampling periods. Larval presence is likely dependent upon the interaction among multiple biotic and abiotic factors. Despite appearance, not all water storage drums are equally suitable for Aedes aegypti development. Exposing water storage drums to direct sunlight or increased heat may be used in conjunction with sealing containers to reduce production of Aedes aegypti when draining and chemical treatment are impractical. PMID:19539592

Hemme, Ryan R.; Tank, Jennifer L.; Chadee, Dave D.; Severson, David W.

2014-01-01

91

Assessing fitness costs for transgenic Aedes aegypti expressing the GFP marker and transposase genes  

E-print Network

Assessing fitness costs for transgenic Aedes aegypti expressing the GFP marker and transposase, dengue, and yellow fever has received much interest due to the ability to transform a number of vector led to questions regarding the fitness of transgenic mosquitoes and the ability of transformed

Hoddle, Mark S.

92

Patterns of Geographic Expansion of Aedes aegypti in the Peruvian Amazon  

PubMed Central

Background and Objectives In the Peruvian Amazon, the dengue vector Aedes aegypti is abundant in large urban centers such as Iquitos. In recent years, it has also been found in a number of neighboring rural communities with similar climatic and socioeconomic conditions. To better understand Ae. aegypti spread, we compared characteristics of communities, houses, and containers in infested and uninfested communities. Methods We conducted pupal-demographic surveys and deployed ovitraps in 34 communities surrounding the city of Iquitos. Communities surveyed were located along two transects: the Amazon River and a 95km highway. We calculated entomological indices, mapped Ae. aegypti presence, and developed univariable and multivariable logistic regression models to predict Ae. aegypti presence at the community, household, or container level. Results Large communities closer to Iquitos were more likely to be infested with Ae. aegypti. Within infested communities, houses with Ae. aegypti had more passively-filled containers and were more often infested with other mosquito genera than houses without Ae. aegypti. For containers, large water tanks/drums and containers with solar exposure were more likely to be infested with Ae. aegypti. Maps of Ae. aegypti presence revealed a linear pattern of infestation along the highway, and a scattered pattern along the Amazon River. We also identified the geographical limit of Ae. aegypti expansion along the highway at 19.3 km south of Iquitos. Conclusion In the Peruvian Amazon, Ae. aegypti geographic spread is driven by human transportation networks along rivers and highways. Our results suggest that urban development and oviposition site availability drive Ae. aegypti colonization along roads. Along rivers, boat traffic is likely to drive long-distance dispersal via unintentional transport of mosquitoes on boats. PMID:25101786

Guagliardo, Sarah Anne; Barboza, Jose Luis; Morrison, Amy C.; Astete, Helvio; Vazquez-Prokopec, Gonzalo; Kitron, Uriel

2014-01-01

93

The Molecular Characterization of a Diuretic Hormone Receptor (GPRdih1) From Females of the Yellow Fever Mosquito, Aedes aegypti (L.)  

E-print Network

In the yellow fever mosquito, Aedes aegypti (L.), hemolymph-circulating diuretic hormones act upon the renal organs (Malpighian tubules) to regulate primary urine composition and secretion rate; however, the molecular endocrine mechanisms underlying...

Jagge, Christopher Lloyd

2011-02-22

94

Competition for amino acids between Wolbachia and the mosquito host, Aedes aegypti.  

PubMed

The endosymbiont Wolbachia represents a promising method of dengue control, as it reduces the ability of the primary vector, the mosquito Aedes aegypti, to transmit viruses. When mosquitoes infected with the virulent Wolbachia strain wMelPop are fed non-human blood, there is a drastic reduction in mosquito fecundity and egg viability. Wolbachia has a reduced genome and is clearly dependent on its host for a wide range of nutritional needs. The fitness defects seen in wMelPop-infected A. aegypti could be explained by competition between the mosquito and the symbiont for essential blood meal nutrients, the profiles of which are suboptimal in non-human blood. Here, we examine cholesterol and amino acids as candidate molecules for competition, as they have critical roles in egg structural development and are known to vary between blood sources. We found that Wolbachia infection reduces total cholesterol levels in mosquitoes by 15-25%. We then showed that cholesterol supplementation of a rat blood meal did not improve fecundity or egg viability deficits. Conversely, amino acid supplementation of sucrose before and after a sheep blood meal led to statistically significant increases in fecundity of approximately 15-20 eggs per female and egg viability of 30-40%. This mosquito system provides the first empirical evidence of competition between Wolbachia and a host over amino acids and may suggest a general feature of Wolbachia-insect associations. These competitive processes could affect many aspects of host physiology and potentially mosquito fitness, a key concern for Wolbachia-based mosquito biocontrol. PMID:24337107

Caragata, Eric P; Rancès, Edwige; O'Neill, Scott L; McGraw, Elizabeth A

2014-01-01

95

Dispersal of male Aedes aegypti in a coastal village in southern Mexico.  

PubMed

Most Aedes aegypti dispersal studies have focused on females because of their central role in dengue virus transmission. Only a few mark-release-recapture (MRR) studies provided insights into male Ae. aegypti dispersal. To fill this knowledge gap, we conducted five male Ae. aegypti MRR experiments in a coastal village in southern Mexico. Small and large male cohorts were marked with fluorescent dusts, released outside buildings, and recaptures were carried out by using backpack aspirators. Recapture rates ranged between 0.35% and 6.55% and median distance traveled was 12-166 meters. A statistically significant difference in median distance traveled with large males dispersing farther than small ones was detected only in one experiment (MRR5: U = 3.5, P < 0.01). Male dispersal data will be useful for constructing and estimating parameter values and validating models that will be used to plan the most effective release strategies for genetically modified male Ae. aegypti. PMID:22492152

Valerio, Laura; Facchinelli, Luca; Ramsey, Janine M; Bond, J Guillermo; Scott, Thomas W

2012-04-01

96

Changing Domesticity of Aedes aegypti in Northern Peninsular Malaysia: Reproductive Consequences and Potential Epidemiological Implications  

PubMed Central

Background The domestic dengue vector Aedes aegypti mosquitoes breed in indoor containers. However, in northern peninsular Malaysia, they show equal preference for breeding in both indoor and outdoor habitats. To evaluate the epidemiological implications of this peridomestic adaptation, we examined whether Ae. aegypti exhibits decreased survival, gonotrophic activity, and fecundity due to lack of host availability and the changing breeding behavior. Methodology/Principal Findings This yearlong field surveillance identified Ae. aegypti breeding in outdoor containers on an enormous scale. Through a sequence of experiments incorporating outdoors and indoors adapting as well as adapted populations, we observed that indoors provided better environment for the survival of Ae. aegypti and the observed death patterns could be explained on the basis of a difference in body size. The duration of gonotrophic period was much shorter in large-bodied females. Fecundity tended to be greater in indoor acclimated females. We also found increased tendency to multiple feeding in outdoors adapted females, which were smaller in size compared to their outdoors breeding counterparts. Conclusion/Significance The data presented here suggest that acclimatization of Ae. aegypti to the outdoor environment may not decrease its lifespan or gonotrophic activity but rather increase breeding opportunities (increased number of discarded containers outdoors), the rate of larval development, but small body sizes at emergence. Size is likely to be correlated with disease transmission. In general, small size in Aedes females will favor increased blood-feeding frequency resulting in higher population sizes and disease occurrence. PMID:22363516

Saifur, Rahman G. M.; Dieng, Hamady; Hassan, Ahmad Abu; Salmah, Md Rawi Che; Satho, Tomomitsu; Miake, Fumio; Hamdan, Ahmad

2012-01-01

97

Pathogenicity of some hypocrealean fungi to adult Aedes aegypti (Diptera: Culicidae).  

PubMed

The pathogenicity of 19 hypocrealean entomopathogenic fungi from seven different genera in adult Aedes aegypti was tested. All fungi proved to be pathogenic, and Isaria fumosorosea, Lecanicillium muscarium, Lecanicillium psalliotae, Metarhizium anisopliae, Metarhizium lepidiotae, Metarhizium majus, Metarhizium frigidum, Paecilomyces carneus, and Paecilomyces lilacinus caused total mortality within 15 days of exposure of mosquitoes to the fungal culture. All fungi developed on dead individuals. The high susceptibility of adults to most tested strains underlines the interest of entomopathogenic fungi-especially those of the genera Metarhizium, Isaria, Paecilomyces and Lecanicillium--for biological control of A. aegypti. PMID:20680340

Leles, Renan Nunes; Sousa, Nathalia Almeida; Rocha, Luiz Fernando Nunes; Santos, Adelair Helena; Silva, Heloisa Helena Garcia; Luz, Christian

2010-10-01

98

Behavioral responses of two dengue virus vectors, Aedes aegypti and Aedes albopictus (Diptera: Culicidae), to DUET and its components.  

PubMed

Ultralow volume droplets of DUET, prallethrin, and sumithrin at a sublethal dose were applied to unfed (nonbloodfed) and bloodfed female Aedes aegypti L. and Aedes albopictus (Skuse) in a wind tunnel. Control spray droplets only contained inert ingredients. Individual mosquitoes were videotaped before, during, and after spraying and various behaviors analyzed. During the spray periods of all three pesticide treatments, mosquitoes spent a greater percentage of time moving, and the distance moved was greater than for mosquitoes in the control treatments. In the postspray period, the percent of time moving increased for mosquitoes exposed to all pesticide treatments compared with the controls. After treatment, all females spent more time walking compared with controls, with unfed Ae. aegypti females walking more after exposure to DUET and sumithrin than after exposure to prallethrin and the control. Pesticide exposure increased flying in both species. Sumithrin exposure increased activity and velocity of unfed mosquitoes more than bloodfed mosquitoes. DUET and sumithrin treatments enhanced activity of Ae. aegypti females more than Ae. albopictus females. PMID:24180111

Clark, Gary G; Golden, Frances V; Allan, Sandra A; Cooperband, Miriam F; McNelly, James R

2013-09-01

99

Vectorial Capacity of Aedes aegypti: Effects of Temperature and Implications for Global Dengue Epidemic Potential  

PubMed Central

Dengue is a mosquito-borne viral disease that occurs mainly in the tropics and subtropics but has a high potential to spread to new areas. Dengue infections are climate sensitive, so it is important to better understand how changing climate factors affect the potential for geographic spread and future dengue epidemics. Vectorial capacity (VC) describes a vector's propensity to transmit dengue taking into account human, virus, and vector interactions. VC is highly temperature dependent, but most dengue models only take mean temperature values into account. Recent evidence shows that diurnal temperature range (DTR) plays an important role in influencing the behavior of the primary dengue vector Aedes aegypti. In this study, we used relative VC to estimate dengue epidemic potential (DEP) based on the temperature and DTR dependence of the parameters of A. aegypti. We found a strong temperature dependence of DEP; it peaked at a mean temperature of 29.3°C when DTR was 0°C and at 20°C when DTR was 20°C. Increasing average temperatures up to 29°C led to an increased DEP, but temperatures above 29°C reduced DEP. In tropical areas where the mean temperatures are close to 29°C, a small DTR increased DEP while a large DTR reduced it. In cold to temperate or extremely hot climates where the mean temperatures are far from 29°C, increasing DTR was associated with increasing DEP. Incorporating these findings using historical and predicted temperature and DTR over a two hundred year period (1901–2099), we found an increasing trend of global DEP in temperate regions. Small increases in DEP were observed over the last 100 years and large increases are expected by the end of this century in temperate Northern Hemisphere regions using climate change projections. These findings illustrate the importance of including DTR when mapping DEP based on VC. PMID:24603439

Liu-Helmersson, Jing; Stenlund, Hans; Wilder-Smith, Annelies; Rocklöv, Joacim

2014-01-01

100

[Pathogenic effect of 3 parasitic nematodes in Aedes aegypti larvae under laboratory conditions in Cuba].  

PubMed

The pathogenic effect of three parasitic nematodes, Romanomermis culicivorax Ross y Smith, 1976, Romanomermis iyengari Welch, 1964, and Strelkovimermis spiculatus Poinar and Camino, 1986, was evaluated at different application doses in larvae of Aedes aegypti. For each experimental unit, one hundred second instar larvae of this mosquitoe were infested with preparasites of the three nematode species in the following proportions: 3:1, 5:1, 10:1, 15:1 and 20:1. Both infestation mean and parasitism rate increased as the doses augmented. Romanomermis culicivorax proved to be more effective at low doses when compared to other species; however, with the 10:1 proportion, all the nematodes caused 100% of mortality. S. spiculatus showed the highest infestation rate. For this reason, a proportion of 10:1 could be recommended to evaluate these nematodes under natural conditions in useless artificial containers as a biological alternative for Aedes aegypti control. PMID:17969278

Rodríguez Rodríguez, Jinnay; García García, Israel; Menéndez, Zulema; García Avila, Israel; Eladio Sánchez, Jesús; Pérez Pacheco, Rafael

2005-01-01

101

Repellent activity of herbal essential oils against Aedes aegypti (Linn.) and Culex quinquefasciatus (Say.)  

PubMed Central

Objective To determine the mosquito repellent activity of herbal essential oils against female Aedes aegypti and Culex quinquefasciatus. Methods On a volunteer's forearm, 0.1 mL of each essential oil was applied to 3 cm×10 cm of exposed skin. The protection time was recorded for 3 min after every 30 min. Results Essential oil from clove oil in olive oil and in coconut oil gave the longest lasting period of 76.50 min and 96.00 min respectively against Aedes aegypti. The citronella grass oil in olive oil, citronella grass oil in coconut oil and lemongrass oil in coconut oil exhibited protection against Culex quinquefasciatus at 165.00, 105.00, and 112.50 min respectively. Conclusions The results clearly indicated that clove, citronella and lemongrass oil were the most promising for repellency against mosquito species. These oils could be used to develop a new formulation to control mosquitoes.

Sritabutra, Duangkamon; Soonwera, Mayura

2013-01-01

102

Mariner Transposition and Transformation of the Yellow Fever Mosquito, Aedes aegypti  

Microsoft Academic Search

The mariner transposable element is capable of interplasmid transposition in the embryonic soma of the yellow fever mosquito, Aedes aegypti. To determine if this demonstrated mobility could be utilized to genetically transform the mosquito, a modified mariner element marked with a wild-type allele of the Drosophila melanogaster cinnabar gene was microinjected into embryos of a kynurenine hydroxylase-deficient, white-eyed recipient strain.

Craig J. Coates; Nijole Jasinskiene; Linda Miyashiro; Anthony A. James

1998-01-01

103

Effect of selected marine and freshwater microalgae on development and survival of the mosquito Aedes aegypti  

Microsoft Academic Search

We isolated and identified strains of marine and freshwater planktonic and benthic microalgae from the vicinity of Indian\\u000a River County, Florida (?27.5°N, 80.34°W), cultivated them in batch culture, and examined their allelopathic activity against\\u000a mosquito larvae. Additional algal material was obtained from Syracuse University and the University of Texas—Austin Algal\\u000a Culture Collection. Mosquito larvae (Aedes aegypti (L.)) from colonies maintained

Jorge R. Rey; Paul E. Hargraves; Sheila M. O’Connell

2009-01-01

104

Repellence of essential oils of aromatic plants growing in Argentina against Aedes aegypti (Diptera: Culicidae)  

Microsoft Academic Search

Mosquitoes are vectors of pathogens to humans and domestic animals and may also have economical impacts. One approach to prevent\\u000a mosquito-borne diseases is bite deterrence through the application of repellents. Currently, there is an interest to search\\u000a for alternative bioactive products to the synthetic active ingredients most widely used in insect repellents. Repellence against\\u000a Aedes aegypti of essential oils extracted

Raquel M. Gleiser; Maria A. Bonino; Julio A. Zygadlo

2011-01-01

105

PCR detection of Dirofilaria immitis in Aedes aegypti and Culex pipiens from urban temperate Argentina  

Microsoft Academic Search

Dirofilariasis, a mosquito-borne disease of dogs caused by the nematode Dirofilaria immitis (Leidy; Spirurida: Onchocercidae), has now become a growing zoonotic concern. Based on direct microscopical observation,\\u000a Aedes aegypti (L.) and Culex pipiens L. (Diptera: Culicidae) have been previously incriminated as potential vectors of D. immitis in urban temperate Argentina. In this study, an effort was made to provide evidence

Darío Vezzani; María Mesplet; Diego F. Eiras; María F. Fontanarrosa; Leonhard Schnittger

2011-01-01

106

Feeding Deterrent Effects of Catnip Oil Components Compared with Two Synthetic Amides Against Aedes aegypti  

Microsoft Academic Search

Recently, catnip, Nepeta cataria L. (Lamiaceae), essential oil has been formulated and marketed as an alternative repellent for protection against biting arthropods by several vendors. We isolated the major active components of catnip oil, E,Z- and Z,E-nepetalactone, and quantitatively measured their antibiting efÞcacy compared with the repellents N,N-diethyl-3-methylbenzamide (deet) and chiral (1S,2S)-2-methylpiperidinyl-3-cyclohexene-1-carboxamide (SS220) against the yellowfever mosquito, Aedes aegypti (L.),

Kamlesh R. Chauhan; Jerome A. Klun; Mustapha Debboun; Matthew Kramer

2005-01-01

107

Blood Feeding and Insulin-like Peptide 3 Stimulate Proliferation of Hemocytes in the Mosquito Aedes aegypti  

PubMed Central

All vector mosquito species must feed on the blood of a vertebrate host to produce eggs. Multiple cycles of blood feeding also promote frequent contacts with hosts, which enhance the risk of exposure to infectious agents and disease transmission. Blood feeding triggers the release of insulin-like peptides (ILPs) from the brain of the mosquito Aedes aegypti, which regulate blood meal digestion and egg formation. In turn, hemocytes serve as the most important constitutive defense in mosquitoes against pathogens that enter the hemocoel. Prior studies indicated that blood feeding stimulates hemocytes to increase in abundance, but how this increase in abundance is regulated is unknown. Here, we determined that phagocytic granulocytes and oenocytoids express the A. aegypti insulin receptor (AaMIR). We then showed that: 1) decapitation of mosquitoes after blood feeding inhibited hemocyte proliferation, 2) a single dose of insulin-like peptide 3 (ILP3) sufficient to stimulate egg production rescued proliferation, and 3) knockdown of the AaMIR inhibited ILP3 rescue activity. Infection studies indicated that increased hemocyte abundance enhanced clearance of the bacterium Escherichia coli at lower levels of infection. Surprisingly, however, non-blood fed females better survived intermediate and high levels of E. coli infection than blood fed females. Taken together, our results reveal a previously unrecognized role for the insulin signaling pathway in regulating hemocyte proliferation. Our results also indicate that blood feeding enhances resistance to E. coli at lower levels of infection but reduces tolerance at higher levels of infection. PMID:21998579

Castillo, Julio; Brown, Mark R.; Strand, Michael R.

2011-01-01

108

In silico models for predicting vector control chemicals targeting Aedes aegypti  

PubMed Central

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

Devillers, J.; Lagneau, C.; Lattes, A.; Garrigues, J.C.; Clemente, M.M.; Yebakima, A.

2014-01-01

109

In silico models for predicting vector control chemicals targeting Aedes aegypti.  

PubMed

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

Devillers, J; Lagneau, C; Lattes, A; Garrigues, J C; Clémenté, M M; Yébakima, A

2014-01-01

110

Oviposition, dispersal, and survival in Aedes aegypti: implications for the efficacy of control strategies.  

PubMed

There is compelling evidence that Aedes aegypti distributes small numbers of eggs among many sites, and that this "skip oviposition" is a driver for dispersal. The behavior is compatible with published results of mark-release-recapture studies, although many of these have been interpreted as evidence for limited dispersal. Skip oviposition also extends the duration of the gonotrophic cycle, the key parameter in the use of parous rates to estimate physiologic age. In addition, contact with multiple oviposition sites was probably a factor in the remarkable success of "perifocal" treatments with DDT in the campaign to eradicate Ae. aegypti from the Americas and the mobility of the vector probably limits the efficacy of attempts to suppress dengue transmission by source reduction and "focal" treatments with aerosols. Innovative approaches that exploit or negate this behavior may be required before effective Ae. aegypti control can become a reality. PMID:17627447

Reiter, Paul

2007-01-01

111

Dispersal of the dengue vector Aedes aegypti within and between rural communities.  

PubMed

Knowledge of mosquito dispersal is critical for vector-borne disease control and prevention strategies and for understanding population structure and pathogen dissemination. We determined Aedes aegypti flight range and dispersal patterns from 21 mark-release-recapture experiments conducted over 11 years (1991-2002) in Puerto Rico and Thailand. Dispersal was compared by release location, sex, age, season, and village. For all experiments, the majority of mosquitoes were collected from their release house or adjacent house. Inter-village movement was detected rarely, with a few mosquitoes moving a maximum of 512 meters from one Thai village to the next. Average dispersal distances were similar for males and females and females released indoors versus outdoors. The movement of Ae. aegypti was not influenced by season or age, but differed by village. Results demonstrate that adult Ae. aegypti disperse relatively short distances, suggesting that people rather than mosquitoes are the primary mode of dengue virus dissemination within and among communities. PMID:15741559

Harrington, Laura C; Scott, Thomas W; Lerdthusnee, Kriangkrai; Coleman, Russell C; Costero, Adriana; Clark, Gary G; Jones, James J; Kitthawee, Sangvorn; Kittayapong, Pattamaporn; Sithiprasasna, Ratana; Edman, John D

2005-02-01

112

Genetic Diversity of Brazilian Aedes aegypti: Patterns following an Eradication Program  

PubMed Central

Background Aedes aegypti is the most important vector of dengue fever in Brazil, where severe epidemics have recently taken place. Ae. aegypti in Brazil was the subject of an intense eradication program in the 1940s and 50s to control yellow fever. Brazil was the largest country declared free of this mosquito by the Pan-American Health Organization in 1958. Soon after relaxation of this program, Ae. aegypti reappeared in this country, and by the early 1980s dengue fever had been reported. The aim of this study is to analyze the present-day genetic patterns of Ae. aegypti populations in Brazil. Methodology/Principal Findings We studied the genetic variation in samples of 11 widely spread populations of Ae. aegypti in Brazil based on 12 well-established microsatellite loci. Our principal finding is that present-day Brazilian Ae. aegypti populations form two distinct groups, one in the northwest and one in the southeast of the country. These two groups have genetic affinities to northern South American countries and the Caribbean, respectively. This is consistent with what has been reported for other genetic markers such as mitochondrial DNA and allele frequencies at the insecticide resistance gene, kdr. Conclusions/Significance We conclude that the genetic patterns in present day populations of Ae. aegypti in Brazil are more consistent with a complete eradication of the species in the recent past followed by re-colonization, rather than the alternative possibility of expansion from residual pockets of refugia. At least two colonizations are likely to have taken place, one from northern South American countries (e.g., Venezuela) that founded the northwestern group, and one from the Caribbean that founded the southeastern group. The proposed source areas were never declared free of Ae. aegypti. PMID:25233218

Monteiro, Fernando A.; Shama, Renata; Martins, Ademir J.; Gloria-Soria, Andrea; Brown, Julia E.; Powell, Jeffrey R.

2014-01-01

113

[Lethal effect of Cuban Myrtaceae on Aedes aegypti (Diptera Cuilicidae)].  

PubMed

The biological activity of the essential foliar oils from 2 Cuban endemic Myrtaceae: Eugenia melanadenia and Psidium rotundatum on A. aegypti larvae was evaluated for the first time at the laboratory level. The probit-log analysis of the results showed the larvicidal effect of both oils with values of CL50 = 0.0085% and CL95 = 0.0104% for E. melanadenia and CL50 = 0.0063% and CL95 = 0.0071% for O. rotundatum. Besides, the diagnostic concentration for both essential oils are given and the possible implications of these findings on field populations of A. aegypti are suggessted. PMID:15849965

Aguilera, Lucita; Navarro, Agustín; Tacoronte, Juan E; Leyva, Maureen; Marquetti, María C

2003-01-01

114

Identification of germline transcriptional regulatory elements in Aedes aegypti  

E-print Network

vector for the yellow fever and dengue viruses, and is also responsible for recent outbreaks of these efforts4 . Vaccines are available for yellow fever, but there are still ,200,000 cases each year and in the early embryo, through overexpression or RNA interference. A edes aegypti is the major vector for yellow

Hay, Bruce A.

115

The basic rules and methods of mosquito rearing (Aedes aegypti)  

PubMed Central

The rearing of Aedes mosquitoes is complex and demanding for several reasons. Aedes larvae are affected by temperature, density and available nutrition, mating is not necessarily accomplished naturally and females need a blood meal to develop eggs. The climate chambers where the mosquitoes are kept are warm and sweaty. Due to these tropical conditions the larvae develop fast and need to be cared for daily. The Laboratory of Entomology in National Institute of Malaria Research Bangalore has cultured different colonies of different vectors successfully. In this paper, we discuss different aspects off the rearing process which affect mosquito fitness and are of importance for the quality of fundamental and applied research. PMID:24754030

Imam, Hashmat; Zarnigar; Sofi, Ghulamuddin; Seikh, Aziz

2014-01-01

116

Behavioral responses of Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles minimus against various synthetic and natural repellent compounds.  

PubMed

The behavioral responses of colony populations of Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles minimus to four essential oils (citronella, hairy basil, catnip, and vetiver), two standard repellents (DEET and picaridin), and two synthetic pyrethroids (deltamethrin and permethrin) were conducted in the laboratory using an excito-repellency test system. Results revealed that Cx. quinquefasciatus and An. minimus exhibited much stronger behavioral responses to all test compounds (65-98% escape for contact, 21.4-94.4% escape for non-contact) compared to Ae. aegypti (3.7-72.2% escape (contact), 0-31.7% (non-contact)) and Ae. albopictus (3.5-94.4% escape (contact), 11.2-63.7% (non-contact)). In brief, essential oil from vetiver elicited the greatest irritant responses in Cx. quinquefasciatus (96.6%) and An. minimus (96.5%) compared to the other compounds tested. The synthetic pyrethroids caused a stronger contact irritant response (65-97.8% escape) than non-contact repellents (0-50.8% escape for non-contact) across all four mosquito species. Picaridin had the least effect on all mosquito species. Findings from the current study continue to support the screening of essential oils from various plant sources for protective properties against field mosquitoes. PMID:25424262

Sathantriphop, Sunaiyana; White, Sabrina A; Achee, Nicole L; Sanguanpong, Unchalee; Chareonviriyaphap, Theeraphap

2014-12-01

117

Distinct variation in vector competence among nine field populations of Aedes aegypti from a Brazilian dengue-endemic risk city  

PubMed Central

Background In Brazil, dengue epidemics erupt sporadically throughout the country and it is unclear if outbreaks may initiate a sustainable transmission cycle. There are few studies evaluating the ability of Brazilian Aedes aegypti populations to transmit dengue virus (DENV). The aim of this study was to compare DENV susceptibility of field-captured Ae. aegypti populations from nine distinct geographic areas of the city of Belo Horizonte in 2009 and 2011. Infection Rate (IR), Vector Competence (VC) and Disseminated Infection Rate (DIR) were determined. Methods Aedes aegypti eggs from each region were collected and reared separately in an insectary. Adult females were experimentally infected with DENV-2 and the virus was detected by qPCR in body and head samples. Data were analyzed with the Statistical Package for the Social Sciences version 17. Results IR varied from 40.0% to 82.5% in 2009 and 60.0% to 100.0% in 2011. VC ranged from 25.0% to 77.5% in 2009 and 25.0% to 80.0% in 2011. DIR oscillated from 68.7% to 100.0% in 2009 and 38.4% to 86.8 in 2011. When the results were evaluated by a logistic model using IR as covariate, North, Barreiro, South-Central and Venda Nova showed the strongest association in 2009. In 2011, a similar association was observed for South-Central, Venda Nova, West and Northeast regions. Using VC as covariate, South-Central and Venda Nova showed the most relevant association in 2009. In 2011, South-Central, Venda Nova and Barreiro presented the greatest revelation associations. When DIR data were analyzed by logistic regression models, Pampulha, South-Central, Venda Nova, West, Northeast and East (2009) as well as South-Central, Venda Nova and West (2011) were the districts showing the strongest associations. Conclusions We conclude that Ae. aegypti populations from Belo Horizonte exhibit wide variation in vector competence to transmit dengue. Therefore, vector control strategies should be adapted to the available data for each region. Further analysis should be conducted to better understand the reasons for this large variability in vector competence and how these parameters correlate with epidemiological findings in subsequent years. PMID:25015526

2014-01-01

118

QTL Mapping of Genome Regions Controlling Temephos Resistance in Larvae of the Mosquito Aedes aegypti  

PubMed Central

Introduction The mosquito Aedes aegypti is the principal vector of dengue and yellow fever flaviviruses. Temephos is an organophosphate insecticide used globally to suppress Ae. aegypti larval populations but resistance has evolved in many locations. Methodology/Principal Findings Quantitative Trait Loci (QTL) controlling temephos survival in Ae. aegypti larvae were mapped in a pair of F3 advanced intercross lines arising from temephos resistant parents from Solidaridad, México and temephos susceptible parents from Iquitos, Peru. Two sets of 200 F3 larvae were exposed to a discriminating dose of temephos and then dead larvae were collected and preserved for DNA isolation every two hours up to 16 hours. Larvae surviving longer than 16 hours were considered resistant. For QTL mapping, single nucleotide polymorphisms (SNPs) were identified at 23 single copy genes and 26 microsatellite loci of known physical positions in the Ae. aegypti genome. In both reciprocal crosses, Multiple Interval Mapping identified eleven QTL associated with time until death. In the Solidaridad×Iquitos (SLD×Iq) cross twelve were associated with survival but in the reciprocal IqxSLD cross, only six QTL were survival associated. Polymorphisms at acetylcholine esterase (AchE) loci 1 and 2 were not associated with either resistance phenotype suggesting that target site insensitivity is not an organophosphate resistance mechanism in this region of México. Conclusions/Significance Temephos resistance is under the control of many metabolic genes of small effect and dispersed throughout the Ae. aegypti genome. PMID:25330200

Reyes-Solis, Guadalupe del Carmen; Saavedra-Rodriguez, Karla; Suarez, Adriana Flores; Black, William C.

2014-01-01

119

Germ band retraction as a landmark in glucose metabolism during Aedes aegypti embryogenesis  

PubMed Central

Background The mosquito A. aegypti is vector of dengue and other viruses. New methods of vector control are needed and can be achieved by a better understanding of the life cycle of this insect. Embryogenesis is a part of A. aegypty life cycle that is poorly understood. In insects in general and in mosquitoes in particular energetic metabolism is well studied during oogenesis, when the oocyte exhibits fast growth, accumulating carbohydrates, lipids and proteins that will meet the regulatory and metabolic needs of the developing embryo. On the other hand, events related with energetic metabolism during A. aegypti embryogenesis are unknown. Results Glucose metabolism was investigated throughout Aedes aegypti (Diptera) embryonic development. Both cellular blastoderm formation (CBf, 5 h after egg laying - HAE) and germ band retraction (GBr, 24 HAE) may be considered landmarks regarding glucose 6-phosphate (G6P) destination. We observed high levels of glucose 6-phosphate dehydrogenase (G6PDH) activity at the very beginning of embryogenesis, which nevertheless decreased up to 5 HAE. This activity is correlated with the need for nucleotide precursors generated by the pentose phosphate pathway (PPP), of which G6PDH is the key enzyme. We suggest the synchronism of egg metabolism with carbohydrate distribution based on the decreasing levels of phosphoenolpyruvate carboxykinase (PEPCK) activity and on the elevation observed in protein content up to 24 HAE. Concomitantly, increasing levels of hexokinase (HK) and pyruvate kinase (PK) activity were observed, and PEPCK reached a peak around 48 HAE. Glycogen synthase kinase (GSK3) activity was also monitored and shown to be inversely correlated with glycogen distribution during embryogenesis. Conclusions The results herein support the hypothesis that glucose metabolic fate changes according to developmental embryonic stages. Germ band retraction is a moment that was characterized as a landmark in glucose metabolism during Aedes aegypti embryogenesis. Furthermore, the results also suggest a role for GSK3 in glycogen balance/distribution during morphological modifications. PMID:20184739

2010-01-01

120

Fine Scale Spatiotemporal Clustering of Dengue Virus Transmission in Children and Aedes aegypti in Rural Thai Villages  

PubMed Central

Background Based on spatiotemporal clustering of human dengue virus (DENV) infections, transmission is thought to occur at fine spatiotemporal scales by horizontal transfer of virus between humans and mosquito vectors. To define the dimensions of local transmission and quantify the factors that support it, we examined relationships between infected humans and Aedes aegypti in Thai villages. Methodology/Principal Findings Geographic cluster investigations of 100-meter radius were conducted around DENV-positive and DENV-negative febrile “index” cases (positive and negative clusters, respectively) from a longitudinal cohort study in rural Thailand. Child contacts and Ae. aegypti from cluster houses were assessed for DENV infection. Spatiotemporal, demographic, and entomological parameters were evaluated. In positive clusters, the DENV infection rate among child contacts was 35.3% in index houses, 29.9% in houses within 20 meters, and decreased with distance from the index house to 6.2% in houses 80–100 meters away (p<0.001). Significantly more Ae. aegypti were DENV-infectious (i.e., DENV-positive in head/thorax) in positive clusters (23/1755; 1.3%) than negative clusters (1/1548; 0.1%). In positive clusters, 8.2% of mosquitoes were DENV-infectious in index houses, 4.2% in other houses with DENV-infected children, and 0.4% in houses without infected children (p<0.001). The DENV infection rate in contacts was 47.4% in houses with infectious mosquitoes, 28.7% in other houses in the same cluster, and 10.8% in positive clusters without infectious mosquitoes (p<0.001). Ae. aegypti pupae and adult females were more numerous only in houses containing infectious mosquitoes. Conclusions/Significance Human and mosquito infections are positively associated at the level of individual houses and neighboring residences. Certain houses with high transmission risk contribute disproportionately to DENV spread to neighboring houses. Small groups of houses with elevated transmission risk are consistent with over-dispersion of transmission (i.e., at a given point in time, people/mosquitoes from a small portion of houses are responsible for the majority of transmission). PMID:22816001

Yoon, In-Kyu; Getis, Arthur; Aldstadt, Jared; Rothman, Alan L.; Tannitisupawong, Darunee; Koenraadt, Constantianus J. M.; Fansiri, Thanyalak; Jones, James W.; Morrison, Amy C.; Jarman, Richard G.; Nisalak, Ananda; Mammen, Mammen P.; Thammapalo, Suwich; Srikiatkhachorn, Anon; Green, Sharone; Libraty, Daniel H.; Gibbons, Robert V.; Endy, Timothy; Pimgate, Chusak; Scott, Thomas W.

2012-01-01

121

Larvicidal efficacy screening of Anacardaciae crude extracts on the dengue hemorrhagic vector, Aedes aegypti.  

PubMed

Vector-borne diseases are still rife because of the re-emergence of diseases transmitted by mosquitoes. The objective of this paper is to evaluate the larvicidal efficacy of crude leaf extract of Mangifera indica, Gluta renghas, and Melanochyla fasciculiflora against vector of dengue hemorrhagic fever, Aedes aegypti. These plant species are endemic species and widely distributed in Malaysian forests. Leaves of Ma. indica, G. renghas and M. fascculiflora were collected from Teluk Bahang National Park, Penang Malaysia. Fractions of leaves were segregated, air-dried, powdered and extracted using Soxhlet with methanol. The solvent was removed by using rotary evaporator to obtain the crude extract. Using WHO standard larval bioassay test method, third instar larvae of Aedes aegypti were exposed to concentration ranging from 200- 4500 ppm of methanol extract for all plant species. Larval mortality was observed after 24 hours exposure. The highest susceptibility and toxicity was recorded by Mangifera indica with the lowest concentration at 800 ppm followed by M. fasciculiflora and G. renghas. This indicates that crude plant extract is very effective in killing Ae. aegypti mosquitoes. This finding may lead to new low cost alternative, environmentally friendly method for mosquito control programs. To our knowledge, this is the first report on larvicidal bioefficacy from endemic Malaysian plants. PMID:25134898

Zuharah, W F; Fadzly, N; Ali, Y; Zakaria, R; Juperi, S; Asyraf, M; Dieng, H

2014-06-01

122

Spatial clustering of Aedes aegypti related to breeding container characteristics in Coastal Ecuador: implications for dengue control.  

PubMed

Mosquito management within households remains central to the control of dengue virus transmission. An important factor in these management decisions is the spatial clustering of Aedes aegypti. We measured spatial clustering of Ae. aegypti in the town of Borbón, Ecuador and assessed what characteristics of breeding containers influenced the clustering. We used logistic regression to assess the spatial extent of that clustering. We found strong evidence for juvenile mosquito clustering within 20 m and for adult mosquito clustering within 10 m, and stronger clustering associations for containers ? 40 L than those < 40 L. Aedes aegypti clusters persisted after adjusting for various container characteristics, suggesting that patterns are likely attributable to short dispersal distances rather than shared characteristics of containers in cluster areas. These findings have implications for targeting Ae. aegypti control efforts. PMID:24002483

Schafrick, Nathaniel H; Milbrath, Meghan O; Berrocal, Veronica J; Wilson, Mark L; Eisenberg, Joseph N S

2013-10-01

123

Spatial Clustering of Aedes aegypti Related to Breeding Container Characteristics in Coastal Ecuador: Implications for Dengue Control  

PubMed Central

Mosquito management within households remains central to the control of dengue virus transmission. An important factor in these management decisions is the spatial clustering of Aedes aegypti. We measured spatial clustering of Ae. aegypti in the town of Borbón, Ecuador and assessed what characteristics of breeding containers influenced the clustering. We used logistic regression to assess the spatial extent of that clustering. We found strong evidence for juvenile mosquito clustering within 20 m and for adult mosquito clustering within 10 m, and stronger clustering associations for containers ? 40 L than those < 40 L. Aedes aegypti clusters persisted after adjusting for various container characteristics, suggesting that patterns are likely attributable to short dispersal distances rather than shared characteristics of containers in cluster areas. These findings have implications for targeting Ae. aegypti control efforts. PMID:24002483

Schafrick, Nathaniel H.; Milbrath, Meghan O.; Berrocal, Veronica J.; Wilson, Mark L.; Eisenberg, Joseph N. S.

2013-01-01

124

Effects of Beauveria bassiana on Survival, Blood-Feeding Success, and Fecundity of Aedes aegypti in Laboratory and Semi-Field Conditions  

PubMed Central

The fungus Beauveria bassiana reduces Aedes aegypti longevity in laboratory conditions, but effects on survival, blood-feeding behavior, and fecundity in realistic environmental conditions have not been tested. Adult, female Ae. aegypti infected with B. bassiana (FI-277) were monitored for blood-feeding success and fecundity in the laboratory. Fungal infection reduced mosquito-human contact by 30%. Fecundity was reduced by (mean ± SD) 29.3 ± 8.6 eggs per female per lifetime in the laboratory; egg batch size and viability were unaffected. Mosquito survival, blood-feeding behavior, and fecundity were also tested in 5 meter×7 meter×4 meter semi-field cages in northern Queensland, Australia. Fungal infection reduced mosquito survival in semi-field conditions by 59–95% in large cages compared with 61–69% in small cages. One semi-field cage trial demonstrated 80% reduction in blood-feeding; a second trial showed no significant effect. Infection did not affect fecundity in large cages. Beauveria bassiana can kill and may reduce biting of Ae. aegypti in semi-field conditions and in the laboratory. These results further support the use of B. bassiana as a potential biocontrol agent against Ae. aegypti. PMID:22492151

Darbro, Jonathan M.; Johnson, Petrina H.; Thomas, Matthew B.; Ritchie, Scott A.; Kay, Brian H.; Ryan, Peter A.

2012-01-01

125

Blood Meal-Derived Heme Decreases ROS Levels in the Midgut of Aedes aegypti and Allows Proliferation of Intestinal Microbiota  

PubMed Central

The presence of bacteria in the midgut of mosquitoes antagonizes infectious agents, such as Dengue and Plasmodium, acting as a negative factor in the vectorial competence of the mosquito. Therefore, knowledge of the molecular mechanisms involved in the control of midgut microbiota could help in the development of new tools to reduce transmission. We hypothesized that toxic reactive oxygen species (ROS) generated by epithelial cells control bacterial growth in the midgut of Aedes aegypti, the vector of Yellow fever and Dengue viruses. We show that ROS are continuously present in the midgut of sugar-fed (SF) mosquitoes and a blood-meal immediately decreased ROS through a mechanism involving heme-mediated activation of PKC. This event occurred in parallel with an expansion of gut bacteria. Treatment of sugar-fed mosquitoes with increased concentrations of heme led to a dose dependent decrease in ROS levels and a consequent increase in midgut endogenous bacteria. In addition, gene silencing of dual oxidase (Duox) reduced ROS levels and also increased gut flora. Using a model of bacterial oral infection in the gut, we show that the absence of ROS resulted in decreased mosquito resistance to infection, increased midgut epithelial damage, transcriptional modulation of immune-related genes and mortality. As heme is a pro-oxidant molecule released in large amounts upon hemoglobin degradation, oxidative killing of bacteria in the gut would represent a burden to the insect, thereby creating an extra oxidative challenge to the mosquito. We propose that a controlled decrease in ROS levels in the midgut of Aedes aegypti is an adaptation to compensate for the ingestion of heme. PMID:21445237

Oliveira, Jose Henrique M.; Goncalves, Renata L. S.; Lara, Flavio A.; Dias, Felipe A.; Gandara, Ana Caroline P.; Menna-Barreto, Rubem F. S.; Edwards, Meredith C.; Laurindo, Francisco R. M.; Silva-Neto, Mario A. C.; Sorgine, Marcos H. F.; Oliveira, Pedro L.

2011-01-01

126

Linking Oviposition Site Choice to Offspring Fitness in Aedes aegypti: Consequences for Targeted Larval Control of Dengue Vectors  

Microsoft Academic Search

BackgroundCurrent Aedes aegypti larval control methods are often insufficient for preventing dengue epidemics. To improve control efficiency and cost-effectiveness, some advocate eliminating or treating only highly productive containers. The population-level outcome of this strategy, however, will depend on details of Ae. aegypti oviposition behavior.Methodology\\/Principal FindingsWe simultaneously monitored female oviposition and juvenile development in 80 experimental containers located across 20 houses

Jacklyn Wong; Amy C. Morrison; Steven T. Stoddard; Helvio Astete; Yui Yin Chu; Imaan Baseer; Thomas W. Scott

2012-01-01

127

Behavioral responses of catnip (Nepeta cataria) by two species of mosquitoes, Aedes aegypti and Anopheles harrisoni, in Thailand.  

PubMed

An investigation of the biological effect of catnip oil (Nepeta cataria L.) on the behavioral response of field collected Aedes aegypti and Anopheles harrisoni was conducted using an automated excitorepellency test system. Aedes aegypti showed significantly higher escape rates from the contact chamber at 5% catnip oil compared to other concentrations (P < 0.05). With Anopheles harrisoni, a high escape response was seen at 2.5% catnip oil from the contact chamber, while in the noncontact chamber a higher escape response was observed at a concentration of 5%. Results showed that this compound exhibits both irritant and repellent actions. PMID:19181058

Polsomboon, Suppaluck; Grieco, John P; Achee, Nicole L; Chauhan, Kamlesh R; Tanasinchayakul, Somchai; Pothikasikorn, Jinrapa; Chareonviriyaphap, Theeraphap

2008-12-01

128

The effect of Piper aduncum Linn. (Family: Piperaceae) essential oil as aerosol spray against Aedes aegypti (L.) and Aedes albopictus Skuse.  

PubMed

The bioefficacy of Piper aduncum L. essential oil formulated in aerosol cans was evaluated against Aedes aegypti and Aedes albopictus in a simulated room. The aerosol spray test was based on the Malaysian test standard for aerosol (MS 1221:1991UDC 632.982.2 modified from WHO 2009 methodology) and examined the knockdown effect within 20 minutes of exposure. Mortality rate after 24 hour of holding period was also determined. A commercial aerosol spray (0.09% prallethrin 0.05% d-phenothrin) was also tested as a comparison. Our results showed that the knockdown effect of the commercial aerosol spray and P. aduncum essential oil spray (8% and 10% concentrations) was significantly higher in Ae. albopictus adult females, when compared with that of Ae. aegypti adult females (P<0.05). There was a significant difference in knockdown between commercial aerosol spray and essential oil spray for both Aedes spp. (P<0.05). The essential oil induced significantly higher mortality in Ae. aegypti (80%) than in Ae. albopictus (71.6%) (P<0.05). The commercial aerosol spray caused 97.7% and 86.5% mortality against Ae. aegypti and Ae. albopictus respectively (P<0.05). Based on these data, P. aduncum essential oil has the potential to be used as an aerosol spray against Aedes spp. PMID:22041743

Misni, Norashiqin; Othman, Hidayatulfathi; Sulaiman, Sallehudin

2011-08-01

129

Effects of insemination and blood-feeding on locomotor activity of Aedes albopictus and Aedes aegypti (Diptera: Culicidae) females under laboratory conditions  

PubMed Central

Background Dengue is an arbovirus disease transmitted by two Aedes mosquitoes: Ae. aegypti and Ae. albopictus. Virgin females of these two species generally show a bimodal and diurnal pattern of activity, with early morning and late afternoon peaks. Although some studies on the flight activity of virgin, inseminated and blood-fed Ae. aegypti females have been carried out under laboratory conditions, little is known about the effects of such physiological states on the locomotor activity of Ae. albopictus and Ae. aegypti females. The aim of this study was to analyze, under laboratory conditions, the effects of insemination and blood-feeding on the locomotor activity of Ae. albopictus and Ae. aegypti females under LD 12:12, at 25°C. Methods Both Ae. albopictus and Ae. aegypti females were obtained from established laboratory colonies. Control groups were represented by virgin/unfed Ae. albopictus and Ae. aegypti females. Experiments were conducted under laboratory conditions, using an activity monitor that registers individual activity every thirty minutes. Results Virgin/unfed Ae. albopictus and Ae. aegypti females showed a diurnal and bimodal pattern of locomotor activity, with peaks at early morning and late afternoon. Insemination and blood-feeding significantly decreased the locomotor activity of Ae. aegypti females, but inseminated/blood-fed Ae. aegypti and Ae. albopictus females showed a similar significant decrease on the locomotor activity compared to virgin/unfed females. Conclusions This study is the first demonstration of the effects of insemination and blood-feeding on the locomotor activity of Ae. albopictus and Ae. aegypti females under artificial conditions. Data suggest that Ae. albopictus and Ae. aegypti females respond in different ways to physiological status changes and such divergence between these two dengue vectors, associated with several ecological differences, could be related to the greater dengue vectorial capacity of Ae. aegypti in Americas in comparison to Ae. albopictus. PMID:24990394

2014-01-01

130

Daily survival rates and dispersal of Aedes aegypti females in Rio de Janeiro, Brazil.  

PubMed

Daily survival rates, life expectancy, dispersal, and parity are important components of vectorial capacity of Aedes aegypti. These parameters were estimated for mosquito populations from a slum and a suburban district in Rio de Janeiro, during the wet and dry seasons in 2005. In each mark-release-recapture experiment, three cohorts of dust-marked Ae. aegypti females were released. Recaptures were carried out daily in randomly selected houses, using backpack aspirators, adult traps, and sticky ovitraps. Recapture varied between 6.81% and 14.26%. Daily survival was estimated by fitting two alternative models: exponential and nonlinear models with correction for the removal of individuals. Slum area presented higher survival and parity rates (68.5%). Dispersal rates were higher in the suburban area, where a maximum dispersal of 363 m was observed. Results suggest intense risk of dengue epidemic, particularly in the urban area. PMID:17426166

Maciel-de-Freitas, Rafael; Codeço, Claudia Torres; Lourenço-de-Oliveira, Ricardo

2007-04-01

131

Repellence of essential oils of aromatic plants growing in Argentina against Aedes aegypti (Diptera: Culicidae).  

PubMed

Mosquitoes are vectors of pathogens to humans and domestic animals and may also have economical impacts. One approach to prevent mosquito-borne diseases is bite deterrence through the application of repellents. Currently, there is an interest to search for alternative bioactive products to the synthetic active ingredients most widely used in insect repellents. Repellence against Aedes aegypti of essential oils extracted from Acantholippia salsoloides, Aloysia catamarcensis, Aloysia polystachya, Lippia integrifolia, Lippia junelliana (Verbenaceae), Baccharis salicifolia, Euphatorium buniifolium, and Tagetes filifolia (Asteraceae) were assessed. Tests were conducted by alternatively exposing untreated and treated forehand to the mosquitoes and counting probing attempts. All essential oils tested were significantly repellent against A. aegypti when compared to untreated controls; L. junelliana was the most repellent and T. filifolia was the least based on the response of the mosquitoes to different concentrations of the essential oils (EO). Repellence may be attributed to the respective main components of each EO. PMID:20838809

Gleiser, Raquel M; Bonino, Maria A; Zygadlo, Julio A

2011-01-01

132

Ovicidal activity of entomopathogenic hyphomycetes on Aedes aegypti (Diptera: Culicidae) under laboratory conditions.  

PubMed

The ovicidal activity of 21 hyphomycete fungi species against Aedes aegypti (L.) (Diptera: Culicidae) was tested. Fungi with ovicidal activity developed on high numbers of eggs (> or =70%) during 25 d of exposure. A clear ovicidal activity with low values of hatch (1.3-40%) was observed after 25 d of incubation with Isaria farinosa (Holm: Fries) Fries, Paecilomyces carneus (Duché & Heim) Brown & Smith, Paecilomyces marquandii (Massee) Hughes, Isaria fumosorosea (Wize), Metarhizium anisopliae (Metschnikoff) Sorokin, Penicillium sp., Paecilomyces lilacinus (Thom) Samson, Beauveria bassiana (Balsamo) Vuillemin, and Evlachovaea kintrischica Borisov & Tarasov. More than 63% of eggs hatched after 25-d exposures to 11 other fungi species deemed as ineffective. These are the first results to show the effects of entomopathogenic fungi against eggs of Ae. aegypti, and they suggest their potential as control agents of this vector. PMID:17915511

Luz, C; Tai, M H H; Santos, A H; Rocha, L F N; Albernaz, D A S; Silva, H H G

2007-09-01

133

Genetics and Morphology of Aedes aegypti (Diptera: Culicidae) in Septic Tanks in Puerto Rico  

PubMed Central

Dengue viruses, primarily transmitted by the mosquito Aedes aegypti (L.), affect an estimated 50–100 million people yearly. Traditional approaches to control mosquito population numbers, such as the use of pesticides, have had only limited success. Atypical mosquito behavior may be one reason why current vector control efforts have been less efficacious than expected. In Puerto Rico, for example, adult Ae. aegypti have been observed emerging from septic tanks. Interestingly, adults emerging from septic tanks are larger on average than adults collected from surface containers. To determine whether adults colonizing septic tanks constitute a separate Ae. aegypti population, we used 12 previously validated microsatellite loci to examine adult mosquitoes collected from both septic tanks and surface containers, but found no evidence to suggest genetic differentiation. Size differences between septic tank and surface mosquitoes were reduced when nutrient levels were held constant across experimental groups. Despite the absence of evidence suggesting a genetic difference between experimental groups in this study, Ae. aegypti emerging from septic tanks may still represent a more dangerous phenotype and should be given special consideration when developing vector control programs and designing public health interventions in the future. PMID:22238867

SOMERS, GERARD; BROWN, JULIA E.; BARRERA, ROBERTO; POWELL, JEFFREY R.

2012-01-01

134

[Resistance of Aedes aegypti (L.) (Diptera: Culicidae) populations to organophosphates temephos in the Paraíba State, Brazil].  

PubMed

Rumors of Aedes aegypti (L.) resistance to temephos in diferent Brazilian states justified this research, whose objective was to verify and characterize the resistance to temephos in A. aegypti populations from Paraíba State. The temephos resistance was evaluated and characterized through a diagnostic dose of 0.012 mg/l and concentration-mortality curves. The mortality data of multiple concentrations were submitted to Probit analysis, and the resistance ratios (RR) were figured out from the CL50s of the survived population and CL50 a laboratory susceptible population. All the A. aegypti populations showed resistance to temephos. The Sítio Piabas population with RR = 4.0, showed lower resistance, the Campina Grande with RR = 6.0, Lagoa do Mato with RR = 9.3 and Capim de Cheiro with RR = 9.0, showed a moderate resistance, and Boqueirão with RR = 11.0, Brejo dos Santos with RR = 16.6 and Itaporanga with RR= 15.6, showed intermediate levels of resistance to temephos. These results confirm the need of a continuous monitoring and managing program of A. aegypti resistance in Paraíba State. PMID:17607466

Beserra, Eduardo B; Fernandes, Carlos R M; de Queiroga, Maiene de F C; de Castro, Francisco P

2007-01-01

135

Insecticidal action of sodium anacardate from Brazilian cashew nut shell liquid against Aedes aegypti.  

PubMed

Aedes aegypti is the major vector of 1 of the most concerning arboviruses of the world, the dengue fever. The only effective way of reducing the incidence of dengue fever is to control the vector mosquito, mainly by application of insecticides to its breeding places. This study was aimed at assessing the insecticidal activity of sodium anacardate, isolated from Brazilian cashew nut shell liquid (CNSL), against the eggs, 3rd instars or pupae of Ae. aegypti. In addition, the acute toxicity of sodium anacardate to mice was also investigated. Sodium anacardate showed toxicity against Ae. aegypti eggs (median effective concentration [EC50] = 162.93 +/- 29.93 microg/ml), larvae (median lethal concentration [LC50] = 55.47 +/- 3.0 microg/ml) and pupae (LC50 = 369.78 - 52.30 microg/ml). On the other hand, even at high dose (0.3 g/kg body weight), this compound did not cause any adverse effects on mice, suggesting that this compound is safe to mammals. Therefore, sodium anacardate may be a viable low-cost alternative to help combat Ae. aegypti. PMID:19852234

Farias, Davi F; Cavalheiro, Mariana G; Viana, Sayonara M; De Lima, Glauber P G; da Rocha-Bezerra, Lady Clarissa B; Ricardo, Nágila M P S; Carvalho, Ana F U

2009-09-01

136

Stormwater Drains and Catch Basins as Sources for Production of Aedes aegypti and Culex quinquefasciatus  

PubMed Central

We present data showing that structures serving as drains and catch basins for stormwater are important sources for production of the mosquito arbovirus vectors Aedes aegypti and Culex quinquefasciatus in Mérida City, México. We examined 1,761 stormwater drains – located in 45 different neighborhoods spread across the city – over dry and wet seasons from March 2012–March 2013. Of the examined stormwater drains, 262 (14.9%) held water at the time they were examined and 123 yielded mosquito immatures. In total, we collected 64,560 immatures representing nine species. The most commonly encountered species were Cx. quinquefasciatus (n=39,269) and Ae. aegypti (n=23,313). Ae. aegypti and Cx. quinquefasciatus were collected during all 11 months when we found water-filled stormwater drains, and both were found in stormwater drains located throughout Mérida City. We also present data for associations between structural characteristics of stormwater drains or water-related characteristics and the abundance of mosquito immatures. In conclusion, stormwater drains produce massive numbers of Ae. aegypti and Cx. quinquefasciatus across Mérida City, both in the wet and dry seasons, and represent non-residential development sites that should be strongly considered for inclusion in the local mosquito surveillance and control program. PMID:24582840

Arana-Guardia, Roger; Baak-Baak, Carlos M.; Lorono-Pino, Maria Alba; Machain-Williams, Carlos; Beaty, Barry J.; Eisen, Lars; Garcia-Rejon, Julian E.

2014-01-01

137

Vacant lots: productive sites for Aedes (Stegomyia) aegypti (Diptera: Culicidae) in Mérida City, México.  

PubMed

We assessed the potential for vacant lots and other nonresidential settings to serve as source environments for Aedes (Stegomyia) aegypti (L.) (Diptera: Culicidae) in Mérida City, México. Mosquito immatures were collected, during November 2011-June 2013, from residential premises (n = 156 site visits) and nonresidential settings represented by vacant lots (50), parking lots (18), and streets or sidewalks (28). Collections totaled 46,025 mosquito immatures of 13 species. Ae. aegypti was the most commonly encountered species accounting for 81.0% of total immatures, followed by Culex quinquefasciatus Say (12.1%). Site visits to vacant lots (74.0%) were more likely to result in collection of Ae. aegypti immatures than residential premises (35.9%). Tires accounted for 75.5% of Ae. aegypti immatures collected from vacant lots. Our data suggest that vacant lots should be considered for inclusion in mosquito surveillance and control efforts in Mérida City, as they often are located near homes, commonly have abundant vegetation, and frequently harbor accumulations of small and large discarded water-holding containers that we now have demonstrated to serve as development sites for immature mosquitoes. In addition, we present data for associations of immature production with various container characteristics, such as storage capacity, water quality, and physical location in the environment. PMID:24724299

Baak-Baak, Carlos M; Arana-Guardia, Roger; Cigarroa-Toledo, Nohemi; Loroño-Pino, Maria Alba; Reyes-Solis, Guadalupe; Machain-Williams, Carlos; Beaty, Barry J; Eisen, Lars; García-Rejón, Julián E

2014-03-01

138

Post-Integration Silencing of piggyBac Transposable Elements in Aedes aegypti  

PubMed Central

The piggyBac transposon, originating in the genome of the Lepidoptera Trichoplusia ni, has a broad host range, making it useful for the development of a number of transposon-based functional genomic technologies including gene vectors, enhancer-, gene- and protein-traps. While capable of being used as a vector for the creation of transgenic insects and insect cell lines, piggyBac has very limited mobility once integrated into the genome of the yellow fever mosquito, Aedes aegypti. A transgenic Aedes aegypti cell line (AagPB8) was created containing three integrated piggyBac elements and the remobilization potential of the elements was tested. The integrated piggyBac elements in AagPB8 were transpositionally silent in the presence of functional transposase, which was shown to be capable of catalyzing the movement of plasmid-borne piggyBac elements in the same cells. The structural integrity of one of the integrated elements along with the quality of element-flanking DNA, which is known to influence transposition rates, were tested in D. melanogaster. The element was found to be structurally intact, capable of transposition and excision in the soma and germ-line of Drosophila melanogaster, and in a DNA sequence context highly conducive to element movement in Drosophila melanogaster. These data show that transpositional silencing of integrated piggyBac elements in the genome of Aedes aegypti appears to be a function of higher scale genome organization or perhaps epigenetic factors, and not due to structural defects or suboptimal integration sites. PMID:23861905

Palavesam, Azhahianambi; Esnault, Caroline; O'Brochta, David A.

2013-01-01

139

Risk factors for the presence of Aedes aegypti and Aedes albopictus in domestic water-holding containers in areas impacted by the Nam Theun 2 hydroelectric project, Laos.  

PubMed

We assessed risk factors for vectors of dengue and chikungunya viruses near a new hydroelectric project, Nam Theun 2, in Laos. Immature stages of Aedes aegypti were found only in sites within 40 km of the urban provincial capital, but Aedes albopictus was found throughout. Aedes aegypti pupae were most common in water storage jars (odds ratio [OR] = 4.72) and tires (OR = 2.99), and Ae. albopictus pupae were associated with tires in 2009 (OR = 10.87) and drums, tires, and jars in 2010 (drums OR = 3.05; tires OR = 3.45, jars OR = 6.59). Compared with water storage vessels, containers used for hygiene, cooking, and drinking were 80% less likely to harbor Ae. albopictus pupae in 2010 (OR = 0.20), and discarded waste was associated with a 3.64 increased odds of infestation. Vector control efforts should focus on source reduction of water storage containers, particularly concrete jars and tires. PMID:23458958

Hiscox, Alexandra; Kaye, Angela; Vongphayloth, Khamsing; Banks, Ian; Piffer, Michele; Khammanithong, Phasouk; Sananikhom, Pany; Kaul, Surinder; Hill, Nigel; Lindsay, Steven W; Brey, Paul T

2013-06-01

140

Risk Factors for the Presence of Aedes aegypti and Aedes albopictus in Domestic Water-Holding Containers in Areas Impacted by the Nam Theun 2 Hydroelectric Project, Laos  

PubMed Central

We assessed risk factors for vectors of dengue and chikungunya viruses near a new hydroelectric project, Nam Theun 2, in Laos. Immature stages of Aedes aegypti were found only in sites within 40 km of the urban provincial capital, but Aedes albopictus was found throughout. Aedes aegypti pupae were most common in water storage jars (odds ratio [OR] = 4.72) and tires (OR = 2.99), and Ae. albopictus pupae were associated with tires in 2009 (OR = 10.87) and drums, tires, and jars in 2010 (drums OR = 3.05; tires OR = 3.45, jars OR = 6.59). Compared with water storage vessels, containers used for hygiene, cooking, and drinking were 80% less likely to harbor Ae. albopictus pupae in 2010 (OR = 0.20), and discarded waste was associated with a 3.64 increased odds of infestation. Vector control efforts should focus on source reduction of water storage containers, particularly concrete jars and tires. PMID:23458958

Hiscox, Alexandra; Kaye, Angela; Vongphayloth, Khamsing; Banks, Ian; Piffer, Michele; Khammanithong, Phasouk; Sananikhom, Pany; Kaul, Surinder; Hill, Nigel; Lindsay, Steven W.; Brey, Paul T.

2013-01-01

141

Susceptibility of field-collected Aedes aegypti (L.) (Diptera: Culicidae) to Bacillus thuringiensis israelensis and temephos.  

PubMed

The susceptibility status of field-collected Aedes aegypti (L.) from a dengue endemic area to Bacillus thuringiensis israelensis (Bti) and temephos was determined. Since August 2007, biweekly ovitrap surveillance (OS) was conducted for 12 mo in 2 sites, A & B, in Shah Alam, Selangor. Site A was treated with a Bti formulation, VectoBac® WG at 500 g/ha, from December 2007 - June 2008 while Site B was subjected to routine dengue vector control activities conducted by the local municipality. Aedes aegypti larvae collected from OS in both sites were bred until F3 and evaluated for their susceptibility. The larvae were pooled according to 3 time periods, which corresponded to Bti treatment phases in site A: August - November 2007 (Bti pre-treatment phase); December 2007 - June 2008 (Bti treatment phase); and July - September 2008 (Bti post-treatment phase). Larvae were bioassayed against Bti or temephos in accordance with WHO standard methods. Larvae collected from Site A was resistant to temephos, while incipient temephos resistant was detected in Site B throughout the study using WHO diagnostic dosage of 0.02 mg/L. The LC50 of temephos ranged between 0.007040 - 0.03799 mg/L throughout the year in both sites. Resistance ratios (LC50) indicated that temephos resistance increased with time, from 1.2 - 6.7 folds. The LC50 of Ae. aegypti larvae to Bti ranged between 0.08890 - 0.1814 mg/L throughout the year in both sites, showing uniform susceptibility of field larvae to Bti, in spite of Site A receiving 18 Bti treatments over a period of 7 mo. No cross-resistance of Ae. aegypti larvae from temephos to Bti was detected. PMID:21399591

Loke, S R; Andy-Tan, W A; Benjamin, S; Lee, H L; Sofian-Azirun, M

2010-12-01

142

Promising Aedes aegypti Repellent Chemotypes Identified through Integrated QSAR, Virtual Screening, Synthesis, and Bioassay  

PubMed Central

Molecular field topology analysis, scaffold hopping, and molecular docking were used as complementary computational tools for the design of repellents for Aedes aegypti, the insect vector for yellow fever, chikungunya, and dengue fever. A large number of analogues were evaluated by virtual screening with Glide molecular docking software. This produced several dozen hits that were either synthesized or procured from commercial sources. Analysis of these compounds by a repellent bioassay resulted in a few highly active chemicals (in terms of minimum effective dosage) as viable candidates for further hit-to-lead and lead optimization effort. PMID:24039693

Oliferenko, Polina V.; Oliferenko, Alexander A.; Poda, Gennadiy I.; Osolodkin, Dmitry I.; Pillai, Girinath G.; Bernier, Ulrich R.; Tsikolia, Maia; Agramonte, Natasha M.; Clark, Gary G.; Linthicum, Kenneth J.; Katritzky, Alan R.

2013-01-01

143

Growth and development of Aedes aegypti larvae at limiting food concentrations.  

PubMed

Mosquitoes have a complex life-cycle with dramatic changes in shape, function, and habitat. Aedes aegypti was studied by growing individual larvae at different concentrations of a defined rich food source. At higher food concentrations, rate of larval growth was faster, but the time required for 4th instar larvae to molt into the pupal stage was unexpectedly extended. These opposite tendencies resulted in constant times from hatching to pupation and up to adult eclosion at permissive food concentrations. The results demonstrate that nutritional conditions of 4th instar larvae impact initiation of the first metamorphic molt. PMID:24524949

Levi, Tal; Ben-Dov, Eitan; Shahi, Preeti; Borovsky, Dov; Zaritsky, Arieh

2014-05-01

144

Electrophoretic variability in the phosphatase system of the yellow-fever mosquito, Aedes aegypti.  

PubMed

Alkaline and acid phosphatases in five inbred strains of the yellow-fever mosquito, Aedes aegypti, were compared by vertical polyacrylamide gel electrophoresis. 1. Polymorphic and monomorphic zones of enzyme activity were observed among both alkaline and acid phosphatases. 2. In the alkaline phosphatase system, seven electrophoretic zones of enzyme activity were detected; all but two of the seven zones showed electrophoretic variability. 3. In the acid phosphatase system, four electrophoretic zones of enzyme activity were detected; all but one of the four zones showed electrophoretic variability. 4. Absence of enzyme activity was observed in some zones and strains among both alkaline and acid phosphatases. PMID:7151398

Igbokwe, E C; Mills, M

1982-01-01

145

[Aedes aegypti in French Guiana. Some aspects of history, general ecology and vertical transmission of the dengue virus].  

PubMed

Aedes aegypti is suspected to be present in the country since the late 18th century, and was responsible of urban yellow fever epidemics in the last century. This mosquito was identified for the first time in French Guiana in 1902. More recently, in 1940, an eradication campaign started and Aedes aegypti was eradicated between 1950 and 1963, date of the reinfestation. During the past 30 years, some dengue outbreaks occurred every 2 to 6 years, and the first dengue haemorrhagic fever epidemic spread over the country in 1992. Actually, Ae. aegypti is distributed almost all inhabited areas of French Guiana: in the towns, villages, smaller human settlements, and was also found in a wild area. The most frequent Ae. aegypti breeding-sources are the outside discarded small containers, other less frequent breeding-sites are the outside flower pots and the outside big containers. The type of breeding-source significantly influences the duration of larval and pupal development. In French Guiana, Ae. aegypti is the only vector of dengue. The vertical transmission of dengue viruses under field conditions was demonstrated. Dengue is thus endemic in the country and has almost the same distribution as Ae. aegypti, with most probably the same possibilities of extension. Ae. aegypti can be considered not only as vector and an amplificator of dengue in French Guiana, but also as a reservoir, even if occasional. PMID:8924768

Fouque, F; Carinci, R

1996-01-01

146

Exsheathment and midgut invasion of nocturnally subperiodic Brugia malayi microfilariae in a refractory vector, Aedes aegypti (Thailand strain).  

PubMed

Exsheathment and midgut invasion of nocturnally subperiodic Brugia malayi microfilariae were analyzed using light and scanning electron microscopy in a refractory vector, Aedes aegypti (Thailand strain). Results showed that exsheathed microfilariae represented only approximately 1 % of the total microfilaria midguts dissected at 5-min post-infected blood meal (PIBM). The percentage of exsheathed microfilariae found in midguts progressively increased to about 20, 60, 80, 90, and 100 % at 1-, 2-5-, 6-12-, 18-36-, and 48-h PIBM, respectively. Importantly, all the microfilariae penetrating the mosquito midguts were exsheathed. Midgut invasion by the exsheathed microfilariae was observed between 2- and 48-h PIBM. SEM analysis revealed sheathed microfilariae surrounded by small particles and maceration of the microfilarial sheath in the midguts, suggesting that the midguts of the refractory mosquitoes might have protein(s) and/or enzyme(s) and/or factor(s) that induce and/or accelerate exsheathment. The microfilariae penetrated the internal face of the peritrophic matrix (PM) by their anterior part and then the midgut epithelium, before entering the hemocoel suggesting that PM was not a barrier against the microfilariae migrating towards the midgut. Melanized microfilariae were discovered in the hemocoel examined at 96-h PIBM suggesting that the refractory mosquitoes used melanization reactions against this parasite. This study provided evidence that A. aegypti (Thailand strain) has refractory mechanisms against B. malayi in both midgut and hemocoel. PMID:25138070

Intakhan, N; Jariyapan, N; Sor-Suwan, S; Phattanawiboon, B; Taai, K; Chanmol, W; Saeung, A; Choochote, W; Bates, P A

2014-11-01

147

Oviposition responses of the mosquitoes Aedes aegypti and Aedes albopictus to experimental plant infusions in laboratory bioassays.  

PubMed

Attraction of the mosquitoes Aedes aegypti and Ae. albopictus to plant infusions was evaluated by using a modified sticky-screen bioassay that improved the resolution of mosquito responses to odorants. Under bioassay conditions, solid-phase microextraction-gas chromatographic analyses of the volatile marker chemical indole showed that odorants diffused from bioassay cups, forming a concentration gradient. Infusions were prepared by separately fermenting senescent leaves of eight plant species in well water. Plant infusions were evaluated over an 8-fold range of leaf biomass and/or a 28 d fermentation period. The responses of gravid females of both mosquito species varied with the plant species and biomass of plant materials used to make infusions, and with the length of the fermentation period. Infusions made from senescent bamboo (Arundinaria gigantea) and white oak (Quercus alba) leaves were significantly attractive to both mosquitoes. In general, infusions prepared by using low biomass of plant material over a 7-14 d fermentation period were most attractive to Ae. aegypti. In contrast, Ae. albopictus was attracted to infusions made using a wider range of plant biomass and over a longer fermentation period. Both mosquito species were more attracted to a non-sterile white oak leaf infusion than to white oak leaf infusion that was prepared using sterilized plant material and water, thus suggesting a role for microbial activity in the production of odorants that mediate the oviposition response of gravid mosquitoes. PMID:20521087

Ponnusamy, Loganathan; Xu, Ning; Böröczky, Katalin; Wesson, Dawn M; Abu Ayyash, Luma; Schal, Coby; Apperson, Charles S

2010-07-01

148

An Integrated Linkage, Chromosome, and Genome Map for the Yellow Fever Mosquito Aedes aegypti  

PubMed Central

Background Aedes aegypti, the yellow fever mosquito, is an efficient vector of arboviruses and a convenient model system for laboratory research. Extensive linkage mapping of morphological and molecular markers localized a number of quantitative trait loci (QTLs) related to the mosquito's ability to transmit various pathogens. However, linking the QTLs to Ae. aegypti chromosomes and genomic sequences has been challenging because of the poor quality of polytene chromosomes and the highly fragmented genome assembly for this species. Methodology/Principal Findings Based on the approach developed in our previous study, we constructed idiograms for mitotic chromosomes of Ae. aegypti based on their banding patterns at early metaphase. These idiograms represent the first cytogenetic map developed for mitotic chromosomes of Ae. aegypti. One hundred bacterial artificial chromosome clones carrying major genetic markers were hybridized to the chromosomes using fluorescent in situ hybridization. As a result, QTLs related to the transmission of the filarioid nematode Brugia malayi, the avian malaria parasite Plasmodium gallinaceum, and the dengue virus, as well as sex determination locus and 183 Mbp of genomic sequences were anchored to the exact positions on Ae. aegypti chromosomes. A linear regression analysis demonstrated a good correlation between positions of the markers on the physical and linkage maps. As a result of the recombination rate variation along the chromosomes, 12 QTLs on the linkage map were combined into five major clusters of QTLs on the chromosome map. Conclusion This study developed an integrated linkage, chromosome, and genome map—iMap—for the yellow fever mosquito. Our discovery of the localization of multiple QTLs in a few major chromosome clusters suggests a possibility that the transmission of various pathogens is controlled by the same genomic loci. Thus, the iMap will facilitate the identification of genomic determinants of traits responsible for susceptibility or refractoriness of the mosquito to diverse pathogens. PMID:23459230

Timoshevskiy, Vladimir A.; Severson, David W.; deBruyn, Becky S.; Black, William C.; Sharakhov, Igor V.; Sharakhova, Maria V.

2013-01-01

149

Evaluation of Location-Specific Predictions by a Detailed Simulation Model of Aedes aegypti Populations  

PubMed Central

Background Skeeter Buster is a stochastic, spatially explicit simulation model of Aedes aegypti populations, designed to predict the outcome of vector population control methods. In this study, we apply the model to two specific locations, the cities of Iquitos, Peru, and Buenos Aires, Argentina. These two sites differ in the amount of field data that is available for location-specific customization. By comparing output from Skeeter Buster to field observations in these two cases we evaluate population dynamics predictions by Skeeter Buster with varying degrees of customization. Methodology/Principal Findings Skeeter Buster was customized to the Iquitos location by simulating the layout of houses and the associated distribution of water-holding containers, based on extensive surveys of Ae. aegypti populations and larval habitats that have been conducted in Iquitos for over 10 years. The model is calibrated by adjusting the food input into various types of containers to match their observed pupal productivity in the field. We contrast the output of this customized model to the data collected from the natural population, comparing pupal numbers and spatial distribution of pupae in the population. Our results show that Skeeter Buster replicates specific population dynamics and spatial structure of Ae. aegypti in Iquitos. We then show how Skeeter Buster can be customized for Buenos Aires, where we only had Ae. aegypti abundance data that was averaged across all locations. In the Argentina case Skeeter Buster provides a satisfactory simulation of temporal population dynamics across seasons. Conclusions This model can provide a faithful description of Ae. aegypti populations, through a process of location-specific customization that is contingent on the amount of data available from field collections. We discuss limitations presented by some specific components of the model such as the description of food dynamics and challenges that these limitations bring to model evaluation. PMID:21799936

Legros, Mathieu; Magori, Krisztian; Morrison, Amy C.; Xu, Chonggang; Scott, Thomas W.; Lloyd, Alun L.; Gould, Fred

2011-01-01

150

Mark-release-recapture study to measure dispersal of the mosquito Aedes aegypti in Cairns, Queensland, Australia.  

PubMed

In Queensland, Australia, in response to isolated cases of dengue infection, larval control of the vector Aedes aegypti (L.) (Diptera: Culicidae) is targeted at breeding sites within 200 m of a case and interior spraying with a pyrethroid adulticide is targeted at premises within 100 m. To ascertain whether these limits are appropriate, we conducted a mark-release-recapture study to measure the dispersal of female Ae. aegypti in the city of Cairns where transmission occurs. Female mosquitoes reared from wild collected eggs were differentially marked with fluorescent dust depending on whether they were to be released blood-fed or non-blood-fed, and a total of 1,948 females was released. A total of 132 sticky ovitraps was set at 64 premises within a 200 m radius and collections of trapped adults were made at 5-15 days post-release. Sixty-seven females (3.4%) were recaptured, with the furthest being caught 200 m from the release point, and the mean distance travelled was 78 m. Overall, 23.1% of the recaptures outside the release site were taken beyond 100 m by day 15. Dispersal was comparable for both blood-fed and non-blood-fed releases. There was a significant tendency for dispersal to be in a north-westerly direction, probably because of the presence of numerous containers and heavy shading by trees in this direction and a busy road to the south of the release point that appeared to inhibit dispersal. The results suggest that adulticiding may have to be extended beyond 100 m if more than 8 days have elapsed since female Ae. aegypti could have fed upon a viraemic dengue case. The study also shows that dispersal is not random, and that it may be possible to maximize vector control by taking into account environmental factors that affect the direction of female mosquito flight. PMID:16336310

Russell, R C; Webb, C E; Williams, C R; Ritchie, S A

2005-12-01

151

Transient expression of the Drosophila melanogaster cinnabar gene rescues eye color in the white eye (WE) strain of Aedes aegypti  

Microsoft Academic Search

The lack of eye pigment in the Aedes aegypti WE (white eye) colony was confirmed to be due to a mutation in the kynurenine hydroxylase gene, which catalyzes one of the steps in the metabolic synthesis of ommochrome eye pigments. Partial restoration of eye color (orange to red phenotype) in pupae and adults occurred in both sexes when first or

Anthony J Cornel; Mark Q. Benedict; Cristina Salazar Rafferty; Antony J Howells; Frank. H Collins

1997-01-01

152

The Use of Ovitraps Baited with Hay Infusion as a Surveillance Tool for Aedes aegypti Mosquitoes in Cambodia  

Microsoft Academic Search

This study was conducted to test (a) if a modified version of the CDC-enhanced ovitrap would attract more gravid female Aedes aegypti mosquitoes than standard ovitraps for more frequent monitoring of oviposition activity, and (b) the placement of ovitraps indoors or outdoors affected their performance. Paired ovitraps were placed in 25 strategically selected houses in Toul Kouk, a village on

Karen A Polson; Chris Curtis; Chang Moh Seng; James G Olson; Ngan Chantha; Sam C Rawlins

153

Oviposition-altering and ovicidal potentials of five essential oils against female adults of the dengue vector, Aedes aegypti L  

Microsoft Academic Search

The oviposition deterrence and ovicidal potential of five different essential oils, peppermint oil (Mentha piperita), basil oil (Ocimum basilicum), rosemary oil (Rosemarinus officinalis), citronella oil (Cymbopogon nardus), and celery seed oil (Apium graveolens), were assessed against female adults of the dengue vector, Aedes aegypti L. Multiple concentration tests were carried out where cups containing 1 mL of different concentrations (100%, 10%,

Radhika Warikoo; Naim Wahab; Sarita Kumar

154

Insecticidal, repellent and oviposition-deterrent activity of selected essential oils against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus  

Microsoft Academic Search

Essential oils extracted from 10 medicinal plants were evaluated for larvicidal, adulticidal, ovicidal, oviposition-deterrent and repellent activities towards three mosquito species; Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. The essential oils of Juniperus macropoda and Pimpinella anisum were highly effective as both larvicidal and ovicidal. The essential oil of P. anisum showed toxicity against 4th instar larvae of A. stephensi

Veena Prajapati; A. K. Tripathi; K. K. Aggarwal; S. P. S. Khanuja

2005-01-01

155

Larvicidal activity of 94 extracts from ten plant species of northeastern of Brazil against Aedes aegypti L. (Diptera: Culicidae)  

Microsoft Academic Search

In an effort to find effective and affordable ways to control of Aedes aegypti L. (Diptera: Culicidae), the larvicidal activities of 94 extracts from ten plant species belonging to eight families [Guettarda grazielae and Spermacoce verticillata (Rubiaceae), Coccoloba mollis and Triplaris americana (Polygonaceae), Eschweilera ovata (Lecytidaceae), Merremia aegyptia (Convolvulaceae), Ouratea nitida (Ochnnaceae), Protium heptaphyllum (Burseraceae), Rourea doniana (Connaraceae), and Tovomita

Patrícia V. Oliveira; Jesú C. Ferreira Jr; Fabyanne S. Moura; Gerson S. Lima; Fernando M. de Oliveira; Patrícia Emanuella S. Oliveira; Lucia M. Conserva; Ana Maria Giulietti; Rosangela P. Lyra Lemos

2010-01-01

156

Copyright 2001 by the Genetics Society of America Integration of the Aedes aegypti Mosquito Genetic Linkage and Physical Maps  

E-print Network

Genetic Linkage and Physical Maps S. E. Brown,* D. W. Severson,,1 L. A. Smith and D. L. Knudson, 2000 ABSTRACT Two approaches were used to correlate the Aedes aegypti genetic linkage map chromosomes using a FISH amplification procedure. The chromosome numbering schemes of the genetic linkage

Severson, David

157

Efficacy of photodynamic therapy against larvae of Aedes aegypti: confocal microscopy and fluorescence-lifetime imaging  

NASA Astrophysics Data System (ADS)

Recently a few demonstration on the use of Photodynamic Reaction as possibility to eliminate larvae that transmit diseases for men has been successfully demonstrated. This promising tool cannot be vastly used due to many problems, including the lake of investigation concerning the mechanisms of larvae killing as well as security concerning the use of photosensitizers in open environment. In this study, we investigate some of the mechanisms in which porphyrin (Photogem) is incorporated on the Aedes aegypti larvae previously to illumination and killing. Larvae at second instar were exposed to the photosensitizer and after 30 minutes imaged by a confocal fluorescence microscope. It was observed the presence of photosensitizer in the gut and at the digestive tract of the larva. Fluorescence-Lifetime Imaging showed greater photosensitizer concentration in the intestinal wall of the samples, which produces a strong decrease of the Photogem fluorescence lifetime. For Photodynamic Therapy exposition to different light doses and concentrations of porphyrin were employed. Three different light sources (LED, Fluorescent lamp, Sun light) also were tested. Sun light and fluorescent lamp shows close to 100% of mortality after 24 hrs. of illumination. These results indicate the potential use of photodynamic effect against the LARVAE of Aedes aegypti.

de Souza, L. M.; Pratavieira, S.; Inada, N. M.; Kurachi, C.; Corbi, J.; Guimarães, F. E. G.; Bagnato, V. S.

2014-03-01

158

Characterization of Aedes aegypti (Diptera: Culcidae) production sites in urban Nicaragua.  

PubMed

To characterize the production patterns of the dengue virus vector Aedes aegypti (L.) (Diptera: Culcidae), pupal surveys were conducted in selected neighborhoods of two major cities in Nicaragua. In León, 833 houses were visited in July and September 2003, corresponding to the beginning and middle of the dengue season; in Managua, 1,365 homes were visited in July 2003. In total, 7,607 containers were characterized, of which 11% were positive for Ae. aegypti larvae and 4% for pupae. In addition to barrels, potted plants and superficial water on tarps and in puddles were identified as highly productive sites. Univariate and multivariate analysis revealed frequency of container use, use of a lid, and rainwater filling as key variables affecting pupal positivity. Importantly, this survey demonstrated the risk associated with the presence of lids, the limited temporal efficacy of temephos, and the lack of association of water availability with risky water storage practices. Finally, we introduce the concept of an efficiency value and an accompanying graphical display system that can facilitate development of targeted pupal control strategies. These data underscore the importance of entomological surveillance of pupal productivity to gather information from which to derive streamlined, efficient, and effective vector control measures to reduce the density of Aedes mosquito larvae and pupae and thus the risk for dengue. PMID:17915519

Hammond, Samantha N; Gordon, Aubree L; Lugo, Emperatriz del C; Moreno, Gilberto; Kuan, Guillermina M; López, María M; López, Josefa D; Delgado, Marco A; Valle, Sonia I; Espinoza, Perla M; Harris, Eva

2007-09-01

159

Mosquito larvicidal activity of seaweeds extracts against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus  

PubMed Central

Objective To identify the larvicidal activity of the seaweed extracts against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus Methods Seaweed extracts of Ulva lactuca, Caulerpa racemosa (C. racemosa), Sargassum microystum, Caulerpa scalpelliformis, Gracilaria corticata, Turbinaria decurrens, Turbinaria conoides and Caulerpa toxifolia were dissolved in DMSO to prepare a graded series of concentration. The test for the larvicidal effect of seaweeds against mosquitos larvae was conducted in accordance with the WHO standard method. Batches of 25 early 4th instar larvae of three mosquitoes were transferred to 250 mL enamel bowl containing 199 mL of distilled water and 1 mL of plant extracts (10-100 µg). Each experiment was conducted with triplicate with concurrent a control group. Results Among the seaweeds extract, C. racemosa showed toxicity against 4th instar larvae of Aedes aegypti, Culex quinquefasciatus, Anopheles stephensi with equivalent LC50 value (0.055?6±0.010?3) µg/mL, (0.067?5±0.136?0) µg/mL and (0.066?1±0.007?6) µg/mL, respectively. Conclusions The present study concluded that, the mosquito larvicidal property of C. racemosa might be the prospective alternative source to control the mosquitoes.

Ali, Mohamed Yacoob Syed; Ravikumar, Sundaram; Beula, Johanson Margaret

2013-01-01

160

Oviposition-Stimulant and Ovicidal Activities of Moringa oleifera Lectin on Aedes aegypti  

PubMed Central

Background Natural insecticides against the vector mosquito Aedes aegypti have been the object of research due to their high level of eco-safety. The water-soluble Moringa oleifera lectin (WSMoL) is a larvicidal agent against A. aegypti. This work reports the effects of WSMoL on oviposition and egg hatching of A. aegypti. Methodology/Principal Findings WSMoL crude preparations (seed extract and 0–60 protein fraction), at 0.1 mg/mL protein concentration, did not affect oviposition, while A. aegypti gravid females laid their eggs preferentially (73%) in vessels containing isolated WSMoL (0.1 mg/mL), compared with vessels containing only distilled water (control). Volatile compounds were not detected in WSMoL preparation. The hatchability of fresh eggs deposited in the solutions in the oviposition assay was evaluated. The numbers of hatched larvae in seed extract, 0–60 protein fraction and WSMoL were 45±8.7 %, 20±11 % and 55±7.5 %, respectively, significantly (p<0.05) lower than in controls containing only distilled water (75–95%). Embryos were visualized inside fresh control eggs, but not within eggs that were laid and maintained in WSMoL solution. Ovicidal activity was also assessed using stored A. aegypti eggs. The protein concentrations able to reduce the hatching rate by 50% (EC50) were 0.32, 0.16 and 0.1 mg/mL for seed extract, 0–60 protein fraction and WSMoL, respectively. The absence of hatching of stored eggs treated with WSMoL at 0.3 mg/mL (EC99) after transfer to medium without lectin indicates that embryos within the eggs were killed by WSMoL. The reduction in hatching rate of A. aegypti was not linked to decrease in bacteria population. Conclusions/Significance WSMoL acted both as a chemical stimulant cue for ovipositing females and ovicidal agent at a given concentration. The oviposition-stimulant and ovicidal activities, combined with the previously reported larvicidal activity, make WSMoL a very interesting candidate in integrated A. aegypti control. PMID:22970317

Santos, Nataly Diniz de Lima; de Moura, Kézia Santana; Napoleão, Thiago Henrique; Santos, Geanne Karla Novais; Coelho, Luana Cassandra Breitenbach Barroso; Navarro, Daniela Maria do Amaral Ferraz; Paiva, Patrícia Maria Guedes

2012-01-01

161

The key breeding sites by pupal survey for dengue mosquito vectors, Aedes aegypti (Linnaeus) and Aedes albopictus (Skuse), in Guba, Cebu City, Philippines.  

PubMed

We conducted this study to assess how well a pupal survey of dengue mosquito vectors, Aedes aegypti and Aedes albopictus, is able to target the most productive breeding sites. The study was carried out monthly during the rainy season (8 months) in 2008 in Cuba, Cebu City, Philippines. The hypotheses tested were: 1) most pupae of Ae. aegypti or Ae. albopictus were produced in a few types of breeding sites and 2) the most productive types of breeding sites for each species were the most abundant. Approximately 2,500 pupae were collected from 554 breeding sites in 279 houses. Thirty-eight point four percent of ten types of breeding sites were positive for Ae. aegypti, and 11.9% of nine types of sites were positive for Ae. albopictus. Plastic drums (40.2%), metal drums (29.6%), and plastic containers (10.5%) were the key sites for Ae. aegypti pupae, whereas bamboo stumps (28.5%), plastic drums (21.1%), and rubber tires (19.1%) were the key sites for Ae. albopictus. The most productive breeding sites for Ae. aegypti were common but not the most common for Ae. albopictus. These results are relevant for dengue vector control programs. PMID:23413699

Edillo, Frances E; Roble, Noel D; Otero, Nenito D

2012-11-01

162

Deletion of the NSm Virulence Gene of Rift Valley Fever Virus Inhibits Virus Replication in and Dissemination from the Midgut of Aedes aegypti Mosquitoes  

PubMed Central

Background Previously, we investigated the role of the Rift Valley fever virus (RVFV) virulence genes NSs and NSm in mosquitoes and demonstrated that deletion of NSm significantly reduced the infection, dissemination, and transmission rates of RVFV in Aedes aegypti mosquitoes. The specific aim of this study was to further characterize midgut infection and escape barriers of RVFV in Ae. aegypti infected with reverse genetics-generated wild type RVFV (rRVF-wt) or RVFV lacking the NSm virulence gene (rRVF-?NSm) by examining sagittal sections of infected mosquitoes for viral antigen at various time points post-infection. Methodology and Principal Findings Ae. aegypti mosquitoes were fed an infectious blood meal containing either rRVF-wt or rRVF-?NSm. On days 0, 1, 2, 3, 4, 6, 8, 10, 12, and 14 post-infection, mosquitoes from each experimental group were fixed in 4% paraformaldehyde, paraffin-embedded, sectioned, and examined for RVFV antigen by immunofluorescence assay. Remaining mosquitoes at day 14 were assayed for infection, dissemination, and transmission. Disseminated infections were observed in mosquitoes as early as three days post infection for both virus strains. However, infection rates for rRVF-?NSm were statistically significantly less than for rRVF-wt. Posterior midgut infections in mosquitoes infected with rRVF-wt were extensive, whereas midgut infections of mosquitoes infected with rRVF-?NSm were confined to one or a few small foci. Conclusions/Significance Deletion of NSm resulted in the reduced ability of RVFV to enter, replicate, and disseminate from the midgut epithelial cells. NSm appears to have a functional role in the vector competence of mosquitoes for RVFV at the level of the midgut barrier. PMID:24551252

Kading, Rebekah C.; Crabtree, Mary B.; Bird, Brian H.; Nichol, Stuart T.; Erickson, Bobbie Rae; Horiuchi, Kalanthe; Biggerstaff, Brad J.; Miller, Barry R.

2014-01-01

163

Reduced oviposition of Aedes aegypti gravid females in domestic containers with predatory fish.  

PubMed

The presence of pathogens or predators in water may alter oviposition behaviour of gravid female Aedes aegypti mosquitoes. We evaluated the oviposition behaviour of A. aegypti in recipients containing larvivorous fish (Betta splendens and Poecilia reticulata). In four breeders, fish specimens were placed in 15 l of dechlorined water. Four control breeders only contained dechlorined water. Breeders with eucatex ovitraps and approximately 100 male and female mosquitoes were placed in wire netting cages. During a period of 7 weeks, eggs on the ovitraps were counted weekly. The median number of eggs laid in recipients with B. splendens (32.5/week) was lower than in those with P. reticulata (200.5/week) and the control group (186.5/week; P < 0.0001). The oviposition activity index (OAI) for P. reticulata did not show any considerable difference between posture in deposits with and without fish (-0005). Deposits with B. splendens showed a lower position than those used as controls (-0627). We conclude that B. splendens can be used to effectively prevent gravid A. aegypti females from laying eggs in large water containers. PMID:19754521

Pamplona, Luciano de Góes Cavalcanti; Alencar, Carlos H; Lima, José Wellington O; Heukelbach, Jörg

2009-11-01

164

Mobility properties of the Hermes transposable element in transgenic lines of Aedes aegypti  

PubMed Central

The Hermes transposable element has been used to genetically transform a wide range of insect species, including the mosquito, Aedes aegypti, a vector of several important human pathogens. Hermes integrations into the mosquito germline are characterized by the non-canonical integration of the transposon and flanking plasmid and, once integrated, Hermes is stable in the presence of its transposase. In an effort to improve the post-integration mobility of Hermes in the germline of Ae. aegypti, a transgenic helper Mos1 construct expressing Hermes transposase under the control of a testis-specific promoter was crossed to a separate transgenic strain containing a target Hermes transposon. In less than 1% of the approximately 1,500 progeny from jumpstarter lines analyzed, evidence of putative Hermes germline remobilizations were detected. These recovered transposition events occur through an aberrant mechanism and provide insight into the non-canonical cut-and-paste transposition of Hermes in the germ line of Ae. aegypti. PMID:20596755

Smith, Ryan C.

2010-01-01

165

Differential transcription profiles in Aedes aegypti detoxification genes after temephos selection.  

PubMed

The mosquito Aedes aegypti is the main vector of Dengue and Yellow Fever flaviviruses. The organophosphate insecticide temephos is a larvicide that is used globally to control Ae. aegypti populations; many of which have in turn evolved resistance. Target site alteration in the acetylcholine esterase of this species has not being identified. Instead, we tracked changes in transcription of metabolic detoxification genes using the Ae. aegypti 'Detox Chip' microarray during five generations of temephos selection. We selected for temephos resistance in three replicates in each of six collections, five from Mexico, and one from Peru. The response to selection was tracked in terms of lethal concentrations. Uniform upregulation was seen in the epsilon class glutathione-S-transferase (eGST) genes in strains from Mexico prior to laboratory selection, while eGSTs in the Iquitos Peru strain became upregulated after five generations of temephos selection. While expression of many carboxyl/cholinesterase esterase (CCE) genes increased with selection, no single esterase was consistently upregulated and this same pattern was noted in the cytochrome P450 monooxygenase (CYP) genes and in other genes involved in reduction or oxidation of xenobiotics. Bioassays using glutathione-S-transferase (GST), CCE and CYP inhibitors suggest that various CCEs instead of GSTs are the main metabolic mechanism conferring resistance to temephos. We show that temephos-selected strains show no cross resistance to permethrin and that genes associated with temephos selection are largely independent of those selected with permethrin in a previous study. PMID:24299217

Saavedra-Rodriguez, K; Strode, C; Flores, A E; Garcia-Luna, S; Reyes-Solis, G; Ranson, H; Hemingway, J; Black, W C

2014-04-01

166

Release of thiotepa sterilized males into caged populations of Aedes aegypti: life table analysis.  

PubMed

Successful SIT trials against mosquitoes in the 1960-70s were achieved by sterilizing male mosquitoes using chemosterilants. Their use was discontinued after concerns were raised about the effect of residues on non-target organisms, although scant evidence has been published. Irradiation is an expensive process; chemosterilization could be an affordable option for implementing SIT programs in developing countries. We compare life table parameters of three Aedes aegypti populations comprising different ratios of thiotepa-treated and non-treated males in order to identify the impact on reproductive potential of the presence of sterile males. No difference was observed in the survival of the treated and untreated males. The release of thiotepa sterilized males into caged Ae. aegypti populations had no effect on death or survival probability of the individuals in the cages but the fecundity of females was significantly reduced, as evaluated by hatch rate and stable age structure parameters. The significant decreases in net reproduction rate, finite rate of natural increase and intrinsic rate of natural increase in populations including sterile males are sufficient to indicate that such populations would not be able to proliferate in natural conditions. This suggests that release of Ae. aegypti thiotepa-treated males could be effective in reducing the reproductive capability of the target population and consequently contribute to vector control. PMID:24513037

Gato, René; Companioni, Ariamys; Bruzón, Rosa Y; Menéndez, Zulema; González, Aileen; Rodríguez, Misladys

2014-04-01

167

Silencing of P-glycoprotein increases mortality in temephos-treated Aedes aegypti larvae.  

PubMed

Re-emergence of vector-borne diseases such as dengue and yellow fever, which are both transmitted by the Aedes aegypti mosquito, has been correlated with insecticide resistance. P-glycoproteins (P-gps) are ATP-dependent efflux pumps that are involved in the transport of substrates across membranes. Some of these proteins have been implicated in multidrug resistance (MDR). In this study, we identified a putative P-glycoprotein in the Ae.?aegypti database based on its significantly high identity with Anopheles gambiae, Culex quinquefasciatus, Drosophila melanogaster and human P-gps. The basal ATPase activity of ATP-binding cassette transporters in larvae was significantly increased in the presence of MDR modulators (verapamil and quinidine). An eightfold increase in Ae.?aegypti P-gp (AaegP-gp) gene expression was detected in temephos-treated larvae as determined by quantitative PCR. To analyse the potential role of AaegP-gp in insecticide efflux, a temephos larvicide assay was performed in the presence of verapamil. The results showed an increase of 24% in temephos toxicity, which is in agreement with the efflux reversing effect. RNA interference (RNAi)-mediated silencing of the AaegP-gp gene caused a significant increase in temephos toxicity (57%). In conclusion, we have demonstrated for the first time in insects that insecticide-induced P-gp expression can be involved in the modulation of insecticide efflux. PMID:23980723

Figueira-Mansur, J; Ferreira-Pereira, A; Mansur, J F; Franco, T A; Alvarenga, E S L; Sorgine, M H F; Neves, B C; Melo, A C A; Leal, W S; Masuda, H; Moreira, M F

2013-12-01

168

Differential transcription profiles in Aedes aegypti detoxification genes following temephos selection  

PubMed Central

The mosquito Aedes aegypti is the main vector of Dengue and Yellow Fever flaviviruses. The organophosphate insecticide temephos is a larvicide that is used globally to control Ae. aegypti populations; many of which have in turn evolved resistance. Target site alteration in the acetylcholine esterase of this species has not being identified. Instead, we tracked changes in transcription of metabolic detoxification genes using the Ae. aegypti ‘Detox Chip’ microarray during five generations of temephos selection. We selected for temephos resistance in three replicates in each of six collections, five from México, and one from Perú. The response to selection was tracked in terms of lethal concentrations (LC50). Uniform upregulation was seen in the epsilon class glutathione-S-transferase genes (eGSTs) in strains from México prior to laboratory selection, while eGSTs in the Iquitos Perú strain became upregulated following five generations of temephos selection. While expression of many esterase genes (CCE) increased with selection, no single esterase was consistently upregulated and this same pattern was noted in the cytochrome P450 genes (CYP) and in other genes involved in reduction or oxidation of xenobiotics. Bioassays using GST, CCE and CYP inhibitors suggest that various CCE instead of GSTs are the main metabolic mechanism conferring resistance to temephos. We show that temephos selected strains show no cross resistance to permethrin and that genes associated with temephos selection are largely independent of those selected with permethrin in a previous study. PMID:24299217

Saavedra-Rodriguez, Karla; Strode, Clare; Flores, Adriana E.; Garcia-Luna, Selene; Reyes-Solis, Guadalupe; Ranson, Hilary; Hemingway, Janet; Black, William C.

2014-01-01

169

Food Availability Alters the Effects of Larval Temperature on Aedes aegypti Growth  

PubMed Central

Variation in temperature and food availability in larval habitats can influence the abundance, body size, and vector competence of the mosquito Aedes aegypti. Although increased temperature has energetic costs for growing larvae, how food resources influence the developmental response of this mosquito species to thermal conditions is unknown. We explored how rearing temperature and food affect allometric scaling between wing size and epidermal cell size in Ae. aegypti. Mosquitoes were reared at 22 and 28°C across a gradient of field-collected detritus designed to simulate commonly observed natural larval food resources. Overall, reduced temperature and increased food level increased wing size, but only temperature affected cell size. Females fed the least food had the longest time to maturation, and their increases in wing size induced by cold temperature were associated with larger, rather than more, cells. By contrast, males fed the most food had the shortest time to maturation, and their increases in wing size induced by cold temperature were associated with more, rather than larger, cells. Therefore, food levels can alter the underlying physiological mechanisms generating temperature-size patterns in mosquitoes, suggesting that the control of development is sensitive to the combination of nutrient and thermal conditions, rather than each independently. Conditions prolonging development time may favor increased cell division over growth. We suggest that understanding the effects of climate change on Ae. aegypti vectorial capacity requires an improved knowledge of how water temperature interacts with limited food resources and competition in aquatic container habitats. PMID:21936315

Padmanabha, H.; Bolker, B.; Lord, C. C.; Rubio, C.; Lounibos, L. P.

2012-01-01

170

A meta-analysis of the factors influencing development rate variation in Aedes aegypti (Diptera: Culicidae)  

PubMed Central

Background Development rates of Aedes aegypti are known to vary with respect to many abiotic and biotic factors including temperature, resource availability, and intraspecific competition. The relative importance of these factors and their interactions are not well established across populations. We performed meta-analysis on a dataset of development rate estimates from 49 studies. Results Meta-analytic results indicated that the environmental factor of temperature is sufficient to explain development rate variability in Ae. aegypti. While diet and density may greatly impact other developmental phenotypes, these results suggest that for development rate these factors should never be considered to the exclusion of temperature. The effect of temperature on development rate is not homogenous or constant. The sources of heterogeneity of the effect of temperature are difficult to analyze due to lack of consistent reporting of larval rearing methods. Conclusions Temperature is the most important ecological determinant of development rate in Ae. aegypti, but its effect is heterogeneous. Ignoring this heterogeneity is problematic for models of vector population and vector-borne disease transmission. PMID:24495345

2014-01-01

171

Temperature, Larval Diet, and Density Effects on Development Rate and Survival of Aedes aegypti (Diptera: Culicidae)  

PubMed Central

Many environmental factors, biotic and abiotic interact to influence organismal development. Given the importance of Aedes aegypti as a vector of human pathogens including dengue and yellow fever, understanding the impact of environmental factors such as temperature, resource availability, and intraspecific competition during development is critical for population control purposes. Despite known associations between developmental traits and factors of diet and density, temperature has been considered the primary driver of development rate and survival. To determine the relative importance of these critical factors, wide gradients of conditions must be considered. We hypothesize that 1) diet and density, as well as temperature influence the variation in development rate and survival, 2) that these factors interact, and this interaction is also necessary to understand variation in developmental traits. Temperature, diet, density, and their two-way interactions are significant factors in explaining development rate variation of the larval stages of Ae. aegypti mosquitoes. These factors as well as two and three-way interactions are significantly associated with the development rate from hatch to emergence. Temperature, but not diet or density, significantly impacted juvenile mortality. Development time was heteroskedastic with the highest variation occurring at the extremes of diet and density conditions. All three factors significantly impacted survival curves of experimental larvae that died during development. Complex interactions may contribute to variation in development rate. To better predict variation in development rate and survival in Ae. aegypti, factors of resource availability and intraspecific density must be considered in addition, but never to the exclusion of temperature. PMID:24498328

Couret, Jannelle; Dotson, Ellen; Benedict, Mark Q.

2014-01-01

172

Aedes aegypti pharate 1st instar quiescence: A case for anticipatory reproductive plasticity  

PubMed Central

Aedes aegypti mosquitoes use pharate 1st instar quiescence to cope with fluctuations in water availability hosting a fully developed 1st instar larvae within the chorion. The duration of this quiescence has been shown to affect larval fitness. This study s ought to determine if an extended egg quiescence can elicit a plastic response resulting in an adult phenotype distinct from adults reared from short quiescence eggs. Our findings indicate that extended pharate 1st quiescence affects the performance and reproductive fitness of the adult female mosquito as well as the nutritional status of its progeny via maternal effects in an adaptive manner. This study demonstrates that phenotypic plasticity results as a consequence of the duration of pharate 1st instar quiescence and alternative phenotypes may exist for this mosquito with quiescence serving as a cue possibly signaling the environmental conditions that follow a dry period. These findings have implications for A. aegypti’s success as a vector, geographic distribution, vector capacity and control. PMID:23298690

Perez, Mario H.; Noriega, Fernando G.

2013-01-01

173

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

PubMed Central

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

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

2012-01-01

174

SSCP analysis of cDNA markers provides a dense linkage map of the Aedes aegypti genome.  

PubMed Central

An intensive linkage map of the yellow fever mosquito, Aedes aegypti, was constructed using single-strand conformation polymorphism (SSCP) analysis of cDNA markers to identify single nucleotide polymorphisms (SNPs). A total of 94 A. aegypti cDNAs were downloaded from GenBank and primers were designed to amplify fragments <500 bp in size. These primer pairs amplified 94 loci, 57 (61%) of which segregated in a single F(1) intercross family among 83 F(2) progeny. This allowed us to produce a dense linkage map of one marker every 2 cM distributed over a total length of 134 cM. Many A. aegypti cDNAs were highly similar to genes in the Drosophila melanogaster genome project. Comparative linkage analysis revealed areas of synteny between the two species. SNP polymorphisms are abundant in A. aegypti genes and should prove useful in both population genetics and mapping studies. PMID:11404335

Fulton, R E; Salasek, M L; DuTeau, N M; Black, W C

2001-01-01

175

Field efficacy of new larvicide products for control of multi-resistant Aedes aegypti populations in Martinique (French West Indies).  

PubMed

World-wide dengue vector control is hampered by the spread of insecticide resistance in Aedes aegypti. We report the resistance status of a wild Ae. aegypti population from Martinique (Vauclin) to conventional larvicides (Bacillus thuringiensis var israeliensis [Bti] and temephos) and potential alternatives (spinosad, diflubenzuron, and pyriproxyfen). The efficacy and residual activity of these insecticides were evaluated under simulated and field conditions. The Vauclin strain exhibited a high level of resistance to temephos, a tolerance to insect growth regulators, and full susceptibility to spinosad and Bti. In simulated trials, pyriproxyfen and Bti showed long residual activities in permanent breeding containers (28 and 37 weeks), whereas under field conditions they failed to curtail Ae. aegypti populations after four weeks. Conversely, diflubenzuron and spinosad showed a residual efficacy of 16 weeks, suggesting that these chemicals may be promising alternatives to Bti and temephos for controlling insecticide-resistant Ae. aegypti populations. PMID:21212213

Marcombe, Sébastien; Darriet, Frédéric; Agnew, Philip; Etienne, Manuel; Yp-Tcha, Marie-Michelle; Yébakima, André; Corbel, Vincent

2011-01-01

176

Toxicity studies for indigenous Bacillus thuringiensis isolates from Malang city, East Java on Aedes aegypti larvae  

PubMed Central

Objective To investigate the toxicity of indigenous Bacillus thuringiensis (B. thuringiensis)isolates from Malang City for controlling Aedes aegypti (Ae. aegypti) larvae. Methods Soil samples were taken from Purwantoro and Sawojajar sub-districts. Bacterial isolation was performed using B. thuringiensis selective media. Phenotypic characteristics of the isolates were obtained with the simple matching method. The growth and prevalence of spores were determined by the Total Plate Count method, and toxicity tests were also performed on the third instar larval stage of Ae. aegypti. The percentage of larval mortality was analysed using probit regression. The LC50 was analysed by ANOVA, and the Tukey HSD interval was 95%. Results Among the 33 selected bacterial isolates, six were obtained (PWR4-31, PWR4-32, SWJ4-2b, SWJ4-4b, SWJ-4k and SWJ5-1) that had a similar phenotype to reference B. thuringiensis. Based on the dendrogram, all of the bacterial isolates were 71% similar. Three isolates that had a higher prevalence of reference B. thuringiensis were PWR4-32, SWJ4-4b and SW5-1, of which the spore prevalence was 52.44%, 23.59%, 34.46%, respectively. These three indigenous isolates from Malang City successfully killed Ae. aegypti larvae. The PWR4-32 isolates were the most effective at killing the larvae. Conclusions Six indigenous B. thuringiensis isolates among the 33 bacterial isolates found in the Sawojajar and Purwantoro sub-districts were toxic to the third instar larvae of Ae. aegypti. The PWR4-32 isolates were identical to the reference B. thuringiensis and had 88% phenotype similarity. The PWR4-32 isolates had the highest spore prevalence (52.44%), and the early stationary phase occurred at 36 h. The PWR4-32 isolates were the most effective at killing Ae. aegypti larvae (LC50-72 h=2.3×108 cells/mL). PMID:23593589

Gama, Zulfaidah Penata; Nakagoshi, Nobukazu; Suharjono; Setyowati, Faridah

2013-01-01

177

Inhibition of luciferase expression in transgenic Aedes aegypti mosquitoes by Sindbis virus expression of antisense luciferase RNA  

PubMed Central

A rapid and reproducible method of inhibiting the expression of specific genes in mosquitoes should further our understanding of gene function and may lead to the identification of mosquito genes that determine vector competence or are involved in pathogen transmission. We hypothesized that the virus expression system based on the mosquito-borne Alphavirus, Sindbis (Togaviridae), may efficiently transcribe effector RNAs that inhibit expression of a targeted mosquito gene. To test this hypothesis, germ-line-transformed Aedes aegypti that express luciferase (LUC) from the mosquito Apyrase promoter were intrathoracically inoculated with a double subgenomic Sindbis (dsSIN) virus TE/3?2J/anti-luc (Anti-luc) that transcribes RNA complementary to the 5? end of the LUC mRNA. LUC activity was monitored in mosquitoes infected with either Anti-luc or control dsSIN viruses expressing unrelated antisense RNAs. Mosquitoes infected with Anti-luc virus exhibited 90% reduction in LUC compared with uninfected and control dsSIN-infected mosquitoes at 5 and 9 days postinoculation. We demonstrate that a gene expressed from the mosquito genome can be inhibited by using an antisense strategy. The dsSIN antisense RNA expression system is an important tool for studying gene function in vivo. PMID:10557332

Johnson, Barbara W.; Olson, Ken E.; Allen-Miura, Tanya; Rayms-Keller, Alfredo; Carlson, Jonathan O.; Coates, Craig J.; Jasinskiene, Nijole; James, Anthony A.; Beaty, Barry J.; Higgs, Stephen

1999-01-01

178

Discovery and Characterization of a Potent and Selective Inhibitor of Aedes aegypti Inward Rectifier Potassium Channels.  

PubMed

Vector-borne diseases such as dengue fever and malaria, which are transmitted by infected female mosquitoes, affect nearly half of the world's population. The emergence of insecticide-resistant mosquito populations is reducing the effectiveness of conventional insecticides and threatening current vector control strategies, which has created an urgent need to identify new molecular targets against which novel classes of insecticides can be developed. We previously demonstrated that small molecule inhibitors of mammalian Kir channels represent promising chemicals for new mosquitocide development. In this study, high-throughput screening of approximately 30,000 chemically diverse small-molecules was employed to discover potent and selective inhibitors of Aedes aegypti Kir1 (AeKir1) channels heterologously expressed in HEK293 cells. Of 283 confirmed screening 'hits', the small-molecule inhibitor VU625 was selected for lead optimization and in vivo studies based on its potency and selectivity toward AeKir1, and tractability for medicinal chemistry. In patch clamp electrophysiology experiments of HEK293 cells, VU625 inhibits AeKir1 with an IC50 value of 96.8 nM, making VU625 the most potent inhibitor of AeKir1 described to date. Furthermore, electrophysiology experiments in Xenopus oocytes revealed that VU625 is a weak inhibitor of AeKir2B. Surprisingly, injection of VU625 failed to elicit significant effects on mosquito behavior, urine excretion, or survival. However, when co-injected with probenecid, VU625 inhibited the excretory capacity of mosquitoes and was toxic, suggesting that the compound is a substrate of organic anion and/or ATP-binding cassette (ABC) transporters. The dose-toxicity relationship of VU625 (when co-injected with probenecid) is biphasic, which is consistent with the molecule inhibiting both AeKir1 and AeKir2B with different potencies. This study demonstrates proof-of-concept that potent and highly selective inhibitors of mosquito Kir channels can be developed using conventional drug discovery approaches. Furthermore, it reinforces the notion that the physical and chemical properties that determine a compound's bioavailability in vivo will be critical in determining the efficacy of Kir channel inhibitors as insecticides. PMID:25375326

Raphemot, Rene; Rouhier, Matthew F; Swale, Daniel R; Days, Emily; Weaver, C David; Lovell, Kimberly M; Konkel, Leah C; Engers, Darren W; Bollinger, Sean F; Hopkins, Corey; Piermarini, Peter M; Denton, Jerod S

2014-01-01

179

Discovery and Characterization of a Potent and Selective Inhibitor of Aedes aegypti Inward Rectifier Potassium Channels  

PubMed Central

Vector-borne diseases such as dengue fever and malaria, which are transmitted by infected female mosquitoes, affect nearly half of the world's population. The emergence of insecticide-resistant mosquito populations is reducing the effectiveness of conventional insecticides and threatening current vector control strategies, which has created an urgent need to identify new molecular targets against which novel classes of insecticides can be developed. We previously demonstrated that small molecule inhibitors of mammalian Kir channels represent promising chemicals for new mosquitocide development. In this study, high-throughput screening of approximately 30,000 chemically diverse small-molecules was employed to discover potent and selective inhibitors of Aedes aegypti Kir1 (AeKir1) channels heterologously expressed in HEK293 cells. Of 283 confirmed screening ‘hits’, the small-molecule inhibitor VU625 was selected for lead optimization and in vivo studies based on its potency and selectivity toward AeKir1, and tractability for medicinal chemistry. In patch clamp electrophysiology experiments of HEK293 cells, VU625 inhibits AeKir1 with an IC50 value of 96.8 nM, making VU625 the most potent inhibitor of AeKir1 described to date. Furthermore, electrophysiology experiments in Xenopus oocytes revealed that VU625 is a weak inhibitor of AeKir2B. Surprisingly, injection of VU625 failed to elicit significant effects on mosquito behavior, urine excretion, or survival. However, when co-injected with probenecid, VU625 inhibited the excretory capacity of mosquitoes and was toxic, suggesting that the compound is a substrate of organic anion and/or ATP-binding cassette (ABC) transporters. The dose-toxicity relationship of VU625 (when co-injected with probenecid) is biphasic, which is consistent with the molecule inhibiting both AeKir1 and AeKir2B with different potencies. This study demonstrates proof-of-concept that potent and highly selective inhibitors of mosquito Kir channels can be developed using conventional drug discovery approaches. Furthermore, it reinforces the notion that the physical and chemical properties that determine a compound's bioavailability in vivo will be critical in determining the efficacy of Kir channel inhibitors as insecticides. PMID:25375326

Raphemot, Rene; Rouhier, Matthew F.; Swale, Daniel R.; Days, Emily; Weaver, C. David; Lovell, Kimberly M.; Konkel, Leah C.; Engers, Darren W.; Bollinger, Sean F.; Hopkins, Corey; Piermarini, Peter M.; Denton, Jerod S.

2014-01-01

180

Identification of blood meal of field caught Aedes aegypti (L.) by multiplex PCR.  

PubMed

Laboratory bred female Aedes aegypti (L.) was used to determine sensitivity of multiplex PCR for detecting human blood meal. Human blood DNA was detected in live fully fed mosquitoes until 3 days after blood feeding, and for 4 weeks when stored at -20 degrees C. Among 890 field caught female mosquito samples examined for vertebrate DNA by multiplex PCR, results were positive for human, pig, dog, cow and mixture of 2 host DNA at 86.1, 3.4, 2.1, 1.0 and 3.6%, respectively, while 3.9% of the samples were negative. Blood feeding pattern must be considered when mosquito control strategies become employed. PMID:20578481

Siriyasatien, Padet; Pengsakul, Theerakamol; Kittichai, Veerayuth; Phumee, Atchara; Kaewsaitiam, Sakchai; Thavara, Usavadee; Tawatsin, Apiwat; Asavadachanukorn, Preecha; Mulla, Mir S

2010-01-01

181

Vapour toxicity & repellence of some essential oils & terpenoids to adults of Aedes aegypti (L) (Diptera: Culicidae).  

PubMed

Bioefficacy of commercially used synthetic insecticides/repellents and potential of selected essential oils and terpenoids were assessed against mosquitoes. Essential oils and terpenoids, were vapourised in commercially manufactured mosquito repellent electronic assemblies and effects of such vapours were tested on 6-7 days old adult female Aedes aegypti. Commercially available 'mats' (coir rectangles) impregnated with allethrin were used as standards for comparison of Kt50 and Kt90 values. Fastest knock-down was seen in case of allethrin, followed by terpeneol (anhydrous) and (-) carvone. Maximum knock-down time was observed for beta citronellol. All compounds exhibited a repellent effect also, terpeneol (anhydrous) being the best, followed by (-) carvone and citronellal. In repellent tests, no mortality was caused by terpenoids, but allethrin caused > 80 per cent knock-down. PMID:8406635

Vartak, P H; Sharma, R N

1993-05-01

182

Larvicidal activity against Aedes aegypti of essential oils from northeast Brazil.  

PubMed

The larvicidal activities of essential oils from the leaves of Artemisia vulgaris L., Cymbopogon flexuosus (Nees ex Steud.) Wats. and Piper tuberculatum Jacq. were evaluated using third-instar larvae of Aedes aegypti. The essential oils were obtained by hydrodistillation and analyzed by GC and GC-MS. The essential oil of P. tuberculqatum had the lowest LC50 value (106.3 +/- 2.2 microg/mL), followed by that of A. vulgaris (114.1 +/- 1.7 microg/mL) and C. flexuosus (121.6 +/- 0.8 micro/mL). The results show that these essential oils may be potent sources of natural larvicides. PMID:23157019

Lavor, Patrícia L; Santiago, Gilvandete M P; Gois, Roberto W da Silva; de Sousa, Leôncio M; Bezerra, Gabrieli da P; Romero, Nirla R; Arriaga, Angela M C; Lemos, Telma L G; Alves, Péricles B; Gomes, Paulo C S

2012-10-01

183

A comparison of larval, ovitrap and MosquiTRAP surveillance for Aedes (Stegomyia) aegypti  

PubMed Central

In Brazil, the entomological surveillance of Aedes (Stegomyia) aegypti is performed by government-mandated larval surveys. In this study, the sensitivities of an adult sticky trap and traditional surveillance methodologies were compared. The study was performed over a 12-week period in a residential neighbourhood of the municipality of Pedro Leopoldo, state of Minas Gerais, Brazil. An ovitrap and a MosquiTRAP were placed at opposite ends of each neighbourhood block (60 traps in total) and inspections were performed weekly. The study revealed significant correlations of moderate strength between the larval survey, ovitrap and MosquiTRAP measurements. A positive relationship was observed between temperature, adult capture measurements and egg collections, whereas precipitation and frequency of rainy days exhibited a negative relationship. PMID:24402144

de Resende, Marcelo Carvalho; Silva, Ivoneide Maria; Ellis, Brett R; Eiras, Alvaro Eduardo

2013-01-01

184

Immunotoxicity activity from various essential oils of Angelica genus from South Korea against Aedes aegypti L.  

PubMed

The leaves of Angelica anomala Lallemant, Angelica cartilagino-marginata var. distans (Nakai) Kitag, Angelica czernevia (Fisch. et Meyer) Kitagawa, Angelica dahurica Benth. et Hooker, Angelica decursiva (Miq.) Franch. & Sav, Angelica fallax Boissieu, Angelica gigas Nakai, Angelica japonica A. gray were essential oil extracted and immunotoxicity effects were studied. The Angelica anomala, A. cartilagino-marginata var. distans, A. czernevia, A. dahurica, A. decursiva, A. fallax, A. gigas, A. japonica essential oil yield were 4.13, 4.83, 4.45, 3.25, 4.11, 4.73, 4.34 and 4.21%. The A. dahurica essential oil had a significant toxic effect against early fourth-stage larvae of Aedes aegypti L with a lethal concentration 50 (LC??) value of 43.12?ppm and an LC?? value of 65.23?ppm. The above indicates that essential oil contents may play a more important role in the toxicity of essential oil. PMID:21506693

Chung, Ill-Min; Kim, Eun-Hye; Lee, Jai-Heon; Lee, Young-Choon; Moon, Hyung-In

2012-02-01

185

Selection of oviposition sites by female Aedes aegypti exposed to two larvicides.  

PubMed

The selection of oviposition sites by female mosquitoes involves the ability to choose less dangerous larval habitats. The aim of the present study was to evaluate the ovipositional behavior of female Aedes aegypti in selecting sites treated with 2 different larvicides. The study was conducted in metal cages with plastic cups containing paper strips and either spinosad or temephos, or dechlorinated water (control). After exposing all treated and control cups to ovipositing female mosquitoes for 3 days, the paper strips were removed and examined for egg laying. Based on the number of eggs laid per treatment, the oviposition index was found positive for spinosad (0.66) but negative for temephos (-0.49), indicating that the natural product spinosad acted as an attractant and temephos as a repellent. PMID:22533085

Quiroz-Martínez, Humberto; Garza-Rodríguez, Mara Ivonne; Trujillo-González, Martha Irma; Zepeda-Cavazos, Irma Guadalupe; Siller-Aguillon, Ilse; Martínez-Perales, Juan Francisco; Rodríguez-Castro, Violeta Ariadna

2012-03-01

186

Composition and immunotoxicity activity of essential oils from Lindera obtusiloba Blume against Aedes aegypti L.  

PubMed

The leaves of Lindera obtusiloba Blume var. obtusiloba were extracted and the major essential oil composition and immunotoxicity effects were studied. The analyses were conducted by gas chromatography and mass spectroscopy (GC-MS) revealed that the essential oils of L. obtusiloba. The L. obtusiloba essential oil yield was 4.23%, and GC/MS analysis revealed that its major constituents were ?-copaene (31.42%), ?-caryophyllene (32.11%), ?-humulene (4.12%), ?-farnesene (4.15%), ?- cadinene (3.21%) and Nerolidol (6.84%). The essential oil had a significant toxic effect against early fourth-stage larvae of Aedes aegypti L with an LC(50) value of 24.32?ppm and an LC(90) value of 36.42?ppm. PMID:20477554

Chung, Ill-Min; Moon, Hyung-In

2011-03-01

187

Transcription of detoxification genes following permethrin selection in the mosquito Aedes aegypti  

PubMed Central

Changes in gene expression before, during and after five generations of permethrin laboratory selection were monitored in six strains of Aedes aegypti: five F2 – F3 collections from the Yucatán Peninsula of México and one F2 from Iquitos, Perú. Three biological replicate lines were generated for each strain. The response to selection was measured as changes in the lethal and knockdown permethrin concentrations (LC50, KC50) and in the frequency of the Ile1,016 substitution in the voltage gated sodium channel (para) gene. Changes in expression of 290 metabolic detoxification genes were measured using the “Aedes Detox” microarray. Selection simultaneously increased the LC50, KC50 and Ile1,016 frequency. There was an inverse relationship between Ile1,016 frequency and the numbers of differentially transcribed genes. The Iquitos strain lacked the Ile1,016 allele and 51 genes were differentially transcribed following selection as compared to 10–18 genes in the Mexican strains. Very few of the same genes were differentially transcribed among field strains but ten cytochrome P450 genes were upregulated in more than one strain. Laboratory adaptation to permethrin in Ae. aegypti is genetically complex and largely conditioned by geographic origin and preexisting target site insensitivity in the para gene. The lack of uniformity in the genes that responded to artificial selection as well as differences in the direction of their responses challenges the assumption that one or a few genes control permethrin metabolic resistance. Attempts to identify one or a few metabolic genes that are predictably associated with permethrin adaptation may be futile. PMID:22032702

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

2011-01-01

188

Characterizing the Aedes aegypti Population in a Vietnamese Village in Preparation for a Wolbachia-Based Mosquito Control Strategy to Eliminate Dengue  

PubMed Central

Background A life-shortening strain of the obligate intracellular bacteria Wolbachia, called wMelPop, is seen as a promising new tool for the control of Aedes aegypti. However, developing a vector control strategy based on the release of mosquitoes transinfected with wMelPop requires detailed knowledge of the demographics of the target population. Methodology/Principal Findings In Tri Nguyen village (611 households) on Hon Mieu Island in central Vietnam, we conducted nine quantitative entomologic surveys over 14 months to determine if Ae. aegypti populations were spatially and temporally homogenous, and to estimate population size. There was no obvious relationship between mosquito (larval, pupal or adult) abundance and temperature and rainfall, and no area of the village supported consistently high numbers of mosquitoes. In almost all surveys, key premises produced high numbers of Ae. aegypti. However, these premises were not consistent between surveys. For an intervention based on a single release of wMelPop-infected Ae. aegypti, release ratios of infected to uninfected adult mosquitoes of all age classes are estimated to be 1.8–6.7?1 for gravid females (and similarly aged males) or teneral adults, respectively. We calculated that adult female mosquito abundance in Tri Nguyen village could range from 1.1 to 43.3 individuals of all age classes per house. Thus, an intervention could require the release of 2–78 wMelPop-infected gravid females and similarly aged males per house, or 7–290 infected teneral female and male mosquitoes per house. Conclusions/Significance Given the variability we encountered, this study highlights the importance of multiple entomologic surveys when evaluating the spatial structure of a vector population or estimating population size. If a single release of wMelPop-infected Ae. aegypti were to occur when wild Ae. aegypti abundance was at its maximum, a preintervention control program would be necessary to ensure that there was no net increase in mosquito numbers. However, because of the short-term temporal heterogeneity, the inconsistent spatial structure and the impact of transient key premises that we observed, the feasibility of multiple releases of smaller numbers of mosquitoes also needs to be considered. In either case, fewer wMelPop-infected mosquitoes would then need to be released, which will likely be more acceptable to householders. PMID:19956588

Jeffery, Jason A. L.; Thi Yen, Nguyen; Nam, Vu Sinh; Nghia, Le Trung; Hoffmann, Ary A.; Kay, Brian H.; Ryan, Peter A.

2009-01-01

189

Evaluation of culture filtrates of Culicinomyces clavisporus: Mycoadulticide for Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi.  

PubMed

The Culicinomyces clavisporus is a fungal pathogen of a wide range of mosquito larvae. The C. clavisporus was isolated from the larvae of Culiseta inornata. We have investigated into potential pathogenicity against the adults of Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi. The culture filtrates released from the strain of C. clavisporus 46258 were grown in the EmYPss broth, were filtered and used for the bioassays after a growth of 15 days. The results demonstrated these metabolites with LC(50), LC(90) and LC(99) values of C. quinquefasciatus, 5.62, 8.71 and 12.59, A. aegypti, 3.0, 7.0 and 9.3, and A. stephensi 2.69, 6.0 and 7.24 ?l/cm(2), respectively after exposure for 24 h. These results compared favorably with the commercial adulticide Gokilaht(®)-S 5EC (d,d-trans-cyphenothrin) that showed 100% mortality at the same concentration. This study successfully identified that the metabolites of C. clavisporus can be used as mosquitoes adulticide as safer alternative to modern synthetic chemical insecticide against mosquito vector of diseases. Further purification can lead to biotechnological exploitation. PMID:21647670

Singh, Gavendra; Prakash, Soam

2012-01-01

190

Essential oils with insecticidal activity against larvae of Aedes aegypti (Diptera: Culicidae).  

PubMed

Insecticidal activity of the essential oils (EOs) isolated from Tagetes lucida, Lippia alba, Lippia origanoides, Eucalyptus citriodora, Cymbopogon citratus, Cymbopogon flexuosus, Citrus sinensis, Swinglea glutinosa, and Cananga odorata aromatic plants, grown in Colombia (Bucaramanga, Santander), and of a mixture of L. alba and L. origanoides EOs were evaluated on Aedes (Stegomyia) aegypti Rockefeller larvae. The EOs were extracted by microwave-assisted hydrodistillation and characterized by gas chromatography-mass spectrometry (GC-MS). The main components of the EOs were identified using their linear retention indices and mass spectra. The lethal concentrations (LCs) of the EOs were determined between the third and fourth instar of A. aegypti. LC50 was determined by probit analysis using mortality rates of bioassays. All essential oils tested showed insecticidal activity. The following values were obtained for C. flexuosus (LC50?=?17.1 ppm); C. sinensis (LC50?=?20.6 ppm); the mixture of L. alba and L. origanoides (LC50?=?40.1 ppm); L. alba (LC50?=?42.2 ppm); C. odorata (LC50?=?52.9 ppm); L. origanoides (LC50?=?53.3 ppm); S. glutinosa (LC50?=?65.7 ppm); T. lucida (LC50?=?66.2 ppm); E. citriodora (LC50?=?71.2 ppm); and C. citratus (LC50?=?123.3 ppm). The EO from C. flexuosus, with citral (geranial?+?neral) as main component, showed the highest larvicidal activity. PMID:24781026

Vera, Sharon Smith; Zambrano, Diego Fernando; Méndez-Sanchez, Stelia Carolina; Rodríguez-Sanabria, Fernando; Stashenko, Elena E; Duque Luna, Jonny E

2014-07-01

191

Development of organophosphorus resistance in Indian strains of Aedes aegypti (L.)*  

PubMed Central

Populations of the yellow-fever mosquito, Aedes aegypti, have developed resistance to cholorinated hydrocarbons in many parts of the world, but not to organophosphorus insecticides. Seven Indian strains of Ae. aegypti were found to be tolerant to DDT and highly susceptible to certain organophosphorus compounds such as Abate, Dursban, fenthion and fenitrothion. Hence selection studies were started with these organophosphorus compounds. Laboratory selections on these strains for 20 generations with Abate, Dursban, malathion, fenthion and fenitrothion increased the tolerance of the F20 larvae to these insecticides by 2.4 times, 3.7 times, 3 times, 5.6 times and 2 times, respectively. The dosage—mortality lines of the successive generations were steep and parallel, suggesting these were instances of tolerance and not of resistance. In contrast, DDT selection showed rapid changes in dosage—mortality lines, indicating the development of resistance. The organophosphorus selected strains generally showed only a 2-3-fold increase in cross-tolerance to other organophosphorus compounds. PMID:5313264

Madhukar, B. V. R.; Pillai, M. K. K.

1970-01-01

192

The design of a community-based health education intervention for the control of Aedes aegypti.  

PubMed

This report describes the process used to develop locally appropriate educational materials and to implement the education component of a community-based Aedes aegypti control program in Merida, Yucatan, Mexico. The process is broken into five stages: formative research, developing recommendations for behavior change, development of educational messages, development and production of educational materials, and distribution of the materials. Appropriate terminology and taxonomies for dengue were obtained from open in-depth interviews; baseline data from a knowledge, beliefs, and practices questionnaire served to confirm this information. A larval survey of house lots was carried out to identify the Ae. aegypti larval production sites found on individual house lots. This enabled the program to target the most important larval habitats. Community groups were organized to work on the development of messages and production of the educational materials to be used. The education intervention was successful in stimulating changes in both knowledge and behavior, which were measured in the evaluations of the intervention. To be successful, community-based strategies must be flexible and adapted to the local setting because of ecologic, cultural, and social differences between localities. PMID:8166346

Lloyd, L S; Winch, P; Ortega-Canto, J; Kendall, C

1994-04-01

193

Circadian clock of Aedes aegypti: effects of blood-feeding, insemination and RNA interference  

PubMed Central

Mosquitoes are the culprits of some of the most important vector borne diseases. A species’ potential as a vector is directly dependent on their pattern of behaviour, which is known to change according to the female’s physiological status such as whether the female is virgin/mated and unfed/blood-fed. However, the molecular mechanism triggered by and/or responsible for such modulations in behaviour is poorly understood. Clock genes are known to be responsible for the control of circadian behaviour in several species. Here we investigate the impact mating and blood-feeding have upon the expression of these genes in the mosquito Aedes aegypti . We show that blood intake, but not insemination, is responsible for the down-regulation of clock genes. Using RNA interference, we observe a slight reduction in the evening activity peak in the fourth day after dstim injection. These data suggest that, as in Drosophila , clock gene expression, circadian behaviour and environmental light regimens are interconnected in Ae. aegypti . PMID:24473806

Gentile, Carla; Rivas, Gustavo Bueno da S; Lima, Jose BP; Bruno, Rafaela Vieira; Peixoto, Alexandre Afranio

2013-01-01

194

Integration of the Aedes aegypti mosquito genetic linkage and physical maps.  

PubMed Central

Two approaches were used to correlate the Aedes aegypti genetic linkage map to the physical map. STS markers were developed for previously mapped RFLP-based genetic markers so that large genomic clones from cosmid libraries could be found and placed to the metaphase chromosome physical maps using standard FISH methods. Eight cosmids were identified that contained eight RFLP marker sequences, and these cosmids were located on the metaphase chromosomes. Twenty-one cDNAs were mapped directly to metaphase chromosomes using a FISH amplification procedure. The chromosome numbering schemes of the genetic linkage and physical maps corresponded directly and the orientations of the genetic linkage maps for chromosomes 2 and 3 were inverted relative to the physical maps. While the chromosome 2 linkage map represented essentially 100% of chromosome 2, approximately 65% of the chromosome 1 linkage map mapped to only 36% of the short p-arm and 83% of the chromosome 3 physical map contained the complete genetic linkage map. Since the genetic linkage map is a RFLP cDNA-based map, these data also provide a minimal estimate for the size of the euchromatic regions. The implications of these findings on positional cloning in A. aegypti are discussed. PMID:11238414

Brown, S E; Severson, D W; Smith, L A; Knudson, D L

2001-01-01

195

Larvicidal activity of major essential oils from stems of Allium monanthum Maxim. against Aedes aegypti L.  

PubMed

The stems of Allium monanthum were extracted, and the major essential oil composition and larvicidal effects were studied. The analyses were conducted by gas chromatography and mass spectroscopy revealed that the essential oils of A. monanthum stems. The A. monanthum essential oil yield was 4.25%, and gas chromatography and mass spectroscopy analysis revealed that its major constituents were dimethyl trisulfide (23.21%), dimethyl tetrasulfide (11.24%) and methlyl propyl trisulfide (8.21%). The essential oil had a significant toxic effect against early fourth-stage larvae of Aedes aegypti L with an LC(50) value of 23.14 ppm and an LC(90) value of 36.31 ppm. Also, dimethyl trisulfide (?95.0%), dimethyl tetrasulfide (?95.0%) and methlyl propyl trisulfide (?95.0%) were tested against the F(21) laboratory strain of A. aegypti. Methlyl propyl trisulfide (?95.0%) has good activity with an LC(50) value of 19.38 ppm. Also, the above indicates that other major compounds may play a more important role in the toxicity of essential oil. PMID:21417962

Moon, Hyung-In

2011-12-01

196

Major essential oils composition and immunotoxicity activity from leaves of Foeniculum vulgare against Aedes aegypti L.  

PubMed

The leaves of Foeniculum vulgare (Umbelliferae) were extracted and the major essential oil composition and immunotoxicity effects were studied. The analyses conducted by gas chromatography and mass spectroscopy (GC-MS) revealed the essential oils of F. vulgare leaves. The F. vulgare essential oil yield was 0.97%, and GC/MS analysis revealed that its major constituents were methyl clavicol (46.3%), ?-phellandrene (18.2%), fenchone (10.6%), (E)-anethole (11.3%), myrcene (3.4%), and ?-pinene (2.1%). The essential oil had a significant toxic effect against early fourth-stage larvae of Aedes aegypti L with an LC(50) value of 41.23?ppm and an LC(90) value of 65.24?ppm. Also, methyl clavicol (?98.0%), ?-phellandrene (?95.0%), fenchone (?98.0%), (E)-anethole (?99.0%), myrcene (?99.0%), and ?-pinene (?99.0%) were tested against the F(21) laboratory strain of A. aegypti. Fenchone (?98.0%) and (E)-anethole (?99.0%) have medium activity with an LC(50) value of 73.11?ppm and 102.41?ppm. The above data indicate that major compounds interaction may play a more important role in the toxicity of essential oil. PMID:21077804

Chung, Ill-Min; Ro, Hee-Myong; Moon, Huyng-In

2011-09-01

197

Aedes aegypti Mosquitoes Exhibit Decreased Repellency by DEET following Previous Exposure  

PubMed Central

DEET (N,N-Diethyl-m-toluamide) is one of the most widely used mosquito repellents. Although DEET has been shown to be extremely effective, recent studies have revealed that certain individual insects are unaffected by its presence. A genetic basis for this has been shown in Aedes aegypti mosquitoes and the fruit fly Drosophila melanogaster, but, for the triatomine bug, Rhodnius prolixus, a decrease in response to DEET occurred shortly after previous exposure, indicating that non-genetic factors may also be involved in DEET “insensitivity”. In this study, we examined host-seeking behaviour and electrophysiological responses of A. aegypti after pre-exposure to DEET. We found that three hours after pre-exposure the mosquitoes showed behavioural insensitivity, and electroantennography revealed this correlated with the olfactory receptor neurons responding less to DEET. The change in behaviour as a result of pre-exposure to DEET has implications for the use of repellents and the ability of mosquitoes to overcome them. PMID:23437043

Stanczyk, Nina M.; Brookfield, John F. Y.; Field, Linda M.; Logan, James G.

2013-01-01

198

Resistance of Aedes aegypti (L.) larvae to temephos in Surabaya, Indonesia.  

PubMed

The resistance of Aedes aegypti mosquitoes to insecticides threatens dengue virus control efforts. In this study, Ae. aegypti larvae collected from 12 subdistricts in Surabaya, Indonesia, where dengue is endemic, were tested for resistance to the organophosphate, temephos. Susceptibility testing, performed according to World Health Organization (WHO) methods, showed all field strains were resistant to temephos at a dose of 0.012 mg/l, with mortality rates at 24 hours of 22% to 60%. Another susceptibility test to determine median lethal time (LT50) indicates resistance ratios ranging from 2.2 to 8.5. Although incipient resistance was detected at a dosage of 1 mg/l, as determined by the LT50, mortalities higher than 80% within 24 hours were detected using the WHO method in nine subdistricts of Surabaya, indicating temephos at 1 mg/l is still effective in field conditions in these areas. In three subdistricts (Tambaksari, Gubeng and Sawahan), the mortality rates were under 80%, indicating possible resistance to temephos. PMID:23082551

Mulyatno, Kris Cahyo; Yamanaka, Atsushi; Ngadino; Konishi, Eiji

2012-01-01

199

Efficacy of various larvicides against Aedes aegypti immatures in the laboratory.  

PubMed

We conducted a laboratory study to evaluate the efficacy of control agents against small larvae, large larvae, and pupae of Aedes aegypti to determine an appropriate larvicide regime to employ in emergency dengue control programs. The control agents included Bacillus thuringiensis var. israelensis (Bti), pyriproxyfen (an insect growth regulator), a larvicidal oil, Aquatain AMF (polydimethylsiloxane, a monomolecular film), and temephos at the recommend application dosages and rates. Our results showed that Bti, pyriproxyfen, and temephos were efficacious (100% mortality) against larvae, irrespective of the instar stage, but not against pupae of Ae. aegypti (1.5-7.8% mortality). Aquatain AMF, on the other hand, was very effective at controlling the pupal stage (100% mortality), but had limited efficacy against small larvae (38.0% mortality) and large larvae (78.0% mortality). The larvicidal oil was effective against all immature stages (93.3-100% mortality). Therefore, we concluded that for effectively interrupting the dengue transmission cycle, larvicides that kill the pupal stage (Aquatain AMF or larvicidal oil) should be included in an emergency dengue control program in addition to Bti, pyriproxyfen, or temephos. PMID:23883850

Wang, Chih-Yuan; Teng, Hwa-Jen; Lee, Si-Jia; Lin, Cheo; Wu, Jhy-Wen; Wu, Ho-Sheng

2013-01-01

200

Evaluation of novel insecticides for control of dengue vector Aedes aegypti (Diptera: Culicidae).  

PubMed

Insecticides are one of the major tools for controlling vector populations and for reducing the transmission of human pathogens. However, there are few new insecticides being developed and marketed for vector control. Herein, we report on the toxicity of six novel insecticides to both adult and larval Aedes aegypti (L). and the toxicity of three novel insect growth regulators (IGRs) to larvae. Four insecticides were highly or moderately toxic to larvae with LC50 values of 16 (chlorfenapyr), 70 (hydramethylnon), 79 (indoxacarb), and 84 ng/ml (imidacloprid). Diafenthiuron and chlorfenapyr were moderately toxic to adult mosquitoes with LC50 values of 13 and 92 ng/cm2, respectively. Imidacloprid was strongly synergized by piperonyl butoxide (PBO) in Ae. aegypti adults, suggesting that neonicotinoids are intrinsically very toxic to adult mosquitoes (in the absence of detoxification). The effect of PBO on the toxicity in adults and larvae was considerably different, both in terms of the insecticides that were synergized (or antagonized for chlorfenapyr versus adults) and in terms of the degree of synergism. This result implies that the cytochrome P450s involved in metabolism of these insecticides are different between adults and larvae. Pyriproxyfen was confirmed as a potent IGR (EC50 of 0.0017 ng/ml) for mosquitoes, although tebufenozide lacked activity. The potential for use of these materials in mosquito control is discussed. PMID:16506447

Paul, Ayesa; Harrington, Laura C; Scott, Jeffrey G

2006-01-01

201

Synergistic repellent and irritant effect of combined essential oils on Aedes aegypti (L.) mosquitoes.  

PubMed

This study was designed to compare the behavioral responses of Aedes aegypti to a single essential oil and to a mixture of two or three essential oils using an excito-repellency test chamber. Mixtures were prepared from essential oils extracted from Litsea cubeba (LC), Litsea salicifolia (LS), and Melaleuca leucadendron (ML). In general, the mixture of essential oils produced a much stronger escape response by Ae. aegypti, regardless of the test conditions. No significant difference in escape responses was seen when the mixture of oils was compared with a standard commercial product containing DEET. Greater contact irritancy was seen from mixed oils of LC and LS than with other mixed oils. Mixtures of LC and LS at 0.075% showed the highest synergistic action (65.5% escaped) compared to that with unmixed oil alone at the same concentration (LC/20% and LS=32.2%). In addition, mixtures of LC and LS at 0.075% demonstrated the highest non-contact repellency (62.7%) and showed a greater effect than the use of LC (20%) or LS (20.3%) alone. We conclude that mixtures of two essential oils show potential as active ingredients for mosquito repellents. PMID:25424258

Noosidum, Atirach; Chareonviriyaphap, Theeraphap; Chandrapatya, Angsumarn

2014-12-01

202

Control of Aedes aegypti larvae in household water containers by Chinese cat fish  

PubMed Central

In 1980-81 an outbreak of dengue fever occurred in Guangdong province and in Guangxi-Zhuang autonomous region in the central-southern part of China. Subsequently, a nationwide survey indicated that the vector of the disease, Aedes aegypti, was confined to the coastal strip of Guangdong and Guangxi-Zhuang. Since the first case in the outbreak occurred in Guangxi-Zhuang, a community-based programme to control A. aegypti was set up in eight fishing villages of this region where the mosquito was breeding in household water containers. The principal method of control was use of the indigenous edible fish Clarias fuscus (Chinese cat fish), which is highly larvivorous and tolerant of harsh environmental conditions. Each container was stocked with a young fish, which could survive there for periods of up to a year. A team of primary medical personnel (barefoot doctors) made sure that the programme was correctly implemented. The programme was monitored from 1981 to 1985 in three of the villages, and the results indicated that the Breteau index remained at a low level throughout this period. PMID:3500803

Neng, Wu; Shusen, Wang; Guangxin, Han; Rongman, Xu; Guangkun, Tang; Chen, Qian

1987-01-01

203

Analysis of cycle Gene Expression in Aedes aegypti Brains by In Situ Hybridization  

PubMed Central

Even though the blood-sucking mosquito Aedes aegypti is one of the most important disease vectors, relatively little is known about the molecular mechanisms underlying processes involved in the temporal pattern of its activity and host seeking behavior. In this study, we analyzed the expression of the cycle (cyc) gene, one of the core components of the circadian clock, in Ae. aegypti brains by in situ hybridization at two different time points in light-dark conditions and compared the results with those obtained using a quantitative PCR assay (qPCR). Within the brain, differential labeling was detected according to distinct areas empirically pre-defined. Six out of seven of these areas showed significantly higher staining at ZT3 (three hours after light-on) compared to ZT11 (one before light-off), which is consistent with the qPCR data. Predominant staining was observed in three of those areas which correspond to positions of the optical and antennal lobes, as well as the region where the neurons controlling activity rhythms are presumably localized. PMID:23300979

Chahad-Ehlers, Samira; Gentile, Carla; Lima, Jose Bento Pereira; Peixoto, Alexandre Afranio; Bruno, Rafaela Vieira

2013-01-01

204

Susceptibility to chlorpyrifos in pyrethroid-resistant populations of Aedes aegypti (Diptera: Culicidae) from Mexico.  

PubMed

Resistance to the organophosphate insecticide chlorpyrifos was evaluated in females from six strains of Aedes aegypti (L.) that expressed high levels of cross-resistance to eight pyrethroid insecticides. Relative to LC50 and LC90 at 24 h of a susceptible New Orleans (NO) strain, three strains were highly resistant to chlorpyrifos (Coatzacoalcos, resistance ratio [RRLC90 = 11.97; Pozarica, RRLC90 = 12.98; and Cosoleacaque, RRLC50 = 13.94 and RRLC90 = 17.57), one strain was moderately resistant (Veracruz, RRLC90 = 5.92), and two strains were susceptible (Tantoyuca and Martinez de la Torre, RRLC50 and RRLC90 < 5) in bottle bioassays according to Centers for Disease Control and Prevention. Furthermore, high levels of alpha- or beta-esterase activity in the sample populations were correlated with resistance, suggesting that esterase activity may be a mechanism causing the development of organophosphate resistance in these populations. Overall, the populations in this study were less resistant to chlorpyrifos than to pyrethroids. Rotation of insecticides used in control activities is recommended to delay or minimize the occurrence of high levels of resistance to chlorpyrifos among local populations of Ae. aegypti. The diagnostic dose and diagnostic time for chlorpyrifos resistance monitoring was determined to be 85 microg per bottle and 30 min, respectively, using the susceptible NO strain. PMID:24897857

Lopez, Beatriz; Ponce, Gustavo; Gonzalez, Jessica A; Gutierrez, Selene M; Villanueva, Olga K; Gonzalez, Gabriela; Bobadilla, Cristina; Rodriguez, Iram P; Black, William C; Flores, Adriana E

2014-05-01

205

Impact of elevated CO2 background levels on the host-seeking behaviour of Aedes aegypti.  

PubMed

Mosquitoes rely on carbon dioxide (CO2) to detect and orient towards their blood hosts. However, the variable and rapid fluctuations of atmospheric CO2 concentrations may have an impact on the host-seeking behaviour of mosquitoes. In this study, we analysed the effect of transient elevated background levels of CO2 on the host-seeking behaviour and the physiological characteristics of the CO2-sensitive olfactory receptor neurones (ORNs) in female yellow fever mosquitoes, Aedes aegypti. We show that the take-off and source contact behaviour of A. aegypti is impeded at elevated background levels of CO2 as a result of masking of the stimulus signal. The mechanism underlying this masking during take-off behaviour is one of sensory constraint. We show that the net response of the CO2-ORNs regulates this CO2-related behaviour. Since these neurones themselves are not habituated or fatigued by the transient elevation of background CO2, we propose that habituation of second-order neurones in response to the elevated CO2-ORN activity could be one mechanism by which the net response is transduced by the olfactory system. The findings from this study may help to predict future shifts in mosquito-host interactions and consequently to predict vectorial capacity in the light of climate change. PMID:24198270

Majeed, Shahid; Hill, Sharon Rose; Ignell, Rickard

2014-02-15

206

Susceptibility to Chlorpyrifos in Pyrethroid-Resistant Populations of Aedes aegypti (Diptera: Culicidae) from Mexico  

PubMed Central

Resistance to the organophosphate insecticide chlorpyrifos was evaluated in females from six strains of Aedes aegypti (L) that expressed high levels of cross resistance to eight pyrethroid insecticides. Relative to LC50 and LC90 at 24h of a susceptible New Orleans (NO) three strains were highly resistant to chlorpyrifos (Coatzacoalcos, resistance ratio (RRLC90) =11.97; Pozarica, RRLC90=12.98; and Cosoleacaque, RRLC50= 13.94 and RRLC90=17.57), one strain was moderately resistant (Veracruz, RR=5.92), and two strains were susceptible (Tantoyuca and Martinez de la Torre, RRLC50 and RRLC90 < 5) in CDC bottle bioassays. Furthermore, high levels of ?/?-esterase activity in the sample populations were correlated with resistance, suggesting that esterase activity may be a mechanism causing the development of organophosphate resistance in these populations. Overall, the populations in this study were less resistant to chlorpyrifos than to pyrethroids. Rotation of insecticides used in control activities is recommended to delay or minimize the occurrence of high levels of resistance to chlorpyrifos among local populations of Ae. aegypti. The diagnostic dose (DD) and diagnostic time (DT) for chlorpyrifos resistance monitoring was determined to be 85 ?g/ bottle and 30min, respectively, using the susceptible NO strain. PMID:24897857

Lopez, Beatriz; Ponce, Gustavo; Gonzalez, Jessica A.; Gutierrez, Selene M.; Villanueva, Olga K.; Gonzalez, Gabriela; Bobadilla, Cristina; Rodriguez, Iram P.; Black, William C.; Flores, Adriana E.

2014-01-01

207

Essential oils and their compounds as Aedes aegypti L. (Diptera: Culicidae) larvicides: review.  

PubMed

This review aims to describe essential oils and their constituent compounds that exhibit bioactivity against Aedes aegypti L. (Diptera: Culicidae) larvae, the immature stage of the primary vector of dengue. This review is based on original articles obtained by searching on major databases. Our literature review revealed that 361 essential oils from 269 plant species have been tested for their larvicidal activity. More than 60 % of these essential oils were considered active (LC50<100 mg/L), and the majority of these active oils were derived from species belonging to Myrtaceae, Lamiaceae, and Rutaceae. The most active essential oils exhibited effective concentrations comparable with the dosage recommended for the use of temephos in container breeding. Approximately 27 % of the plants studied for their larvicidal activity against A. aegypti were collected in Brazil. Essential oils rich in phenylpropanoids, oxygenated sesquiterpenes, and monoterpene hydrocarbons were found to be the most active. When the isolates were tested, phenylpropanoids and monoterpene hydrocarbons were the most active compound classes. We describe the plant parts used and the major constituents of the essential oils. In addition, we discuss factors affecting the activity (such as plant parts, age of the plant, chemotypes, larval source, and methods used), structure-activity relationships, and mechanisms of action of the essential oils and their compounds. Essential oils have been widely investigated and show high larvicidal activity against A. aegypti. This review reveals that the essential oils are effective alternatives for the production of larvicides, which can be used in vector-borne disease control programmes. PMID:24265058

Dias, Clarice Noleto; Moraes, Denise Fernandes Coutinho

2014-02-01

208

Comparative field efficacy of newly developed formulations of larvicides against Aedes aegypti (L.) (Diptera: Culicidae).  

PubMed

Aedes aegypti (L.) is known as vector of dengue and chikungunya fever. Larvicides are used to control this vector. We evaluated the efficacy of newly developed formulations of larvicides to control Ae. aegypti under field conditions for 24 weeks post single application. Mosdop P and Mosdop TB containing diflubenzuron (2% and 40 mg/tablet, respectively) as the active ingredient, were applied at a dosage of 0.1 mg a.i./1 and Mosquit TB10, Mosquit TB100 and Temecal containing temephos (1%, 10% and 1%, respectively) as the active ingredient were applied at a dosage of 1 mg active ingredent (a.i.) to 200 liter water storage jars. Two water regimens were used in the jars: in one regimen the jar was kept full of water all the time and in the other regimen a full jar had half the volume removed and refilled weekly. The larvicidal efficacy was reported as the level of inhibition of emergence (IE%) calculated based on the pupal skins in the jars versus the original number of larvae added. Mosdop P, Mosdop TB, Mosquit TB10, Mosquit TB100 and Temecal showed complete larvicidal efficacy (100% IE) in the constantly full jars for 16, 17, 14, 20 and 13 weeks posttreatment, respectively; in the jars where half the volum of water was replaced weekly, the larvicides had complete larvicidal efficacy (100% IE) for 19, 20, 17, 24 and 15 weeks post-treatment, respectively. The five larvicide regimens evaluated in this study are effective for controlling Ae. aegypti larvae. PMID:24437310

Thavara, Usavadee; Tawatsin, Apiwat; Chompoosri, Jakkrawarn; Bhakdeenuan, Payu; Khamsawads, Chayada; Sangkitporn, Somchai; Siriyasatien, Padet; Asavadachanukorn, Preecha; Boonmuen, Saibua; Mulla, Mir S

2013-09-01

209

Temephos Resistance in Aedes aegypti in Colombia Compromises Dengue Vector Control  

PubMed Central

Background Control and prevention of dengue relies heavily on the application of insecticides to control dengue vector mosquitoes. In Colombia, application of the larvicide temephos to the aquatic breeding sites of Aedes aegypti is a key part of the dengue control strategy. Resistance to temephos was recently detected in the dengue-endemic city of Cucuta, leading to questions about its efficacy as a control tool. Here, we characterize the underlying mechanisms and estimate the operational impact of this resistance. Methodology/Principal Findings Larval bioassays of Ae. aegypti larvae from Cucuta determined the temephos LC50 to be 0.066 ppm (95% CI 0.06–0.074), approximately 15× higher than the value obtained from a susceptible laboratory colony. The efficacy of the field dose of temephos at killing this resistant Cucuta population was greatly reduced, with mortality rates <80% two weeks after application and <50% after 4 weeks. Neither biochemical assays nor partial sequencing of the ace-1 gene implicated target site resistance as the primary resistance mechanism. Synergism assays and microarray analysis suggested that metabolic mechanisms were most likely responsible for the temephos resistance. Interestingly, although the greatest synergism was observed with the carboxylesterase inhibitor, DEF, the primary candidate genes from the microarray analysis, and confirmed by quantitative PCR, were cytochrome P450 oxidases, notably CYP6N12, CYP6F3 and CYP6M11. Conclusions/Significance In Colombia, resistance to temephos in Ae. aegypti compromises the duration of its effect as a vector control tool. Several candidate genes potentially responsible for metabolic resistance to temephos were identified. Given the limited number of insecticides that are approved for vector control, future chemical-based control strategies should take into account the mechanisms underlying the resistance to discern which insecticides would likely lead to the greatest control efficacy while minimizing further selection of resistant phenotypes. PMID:24069492

Grisales, Nelson; Poupardin, Rodolphe; Gomez, Santiago; Fonseca-Gonzalez, Idalyd; Ranson, Hilary; Lenhart, Audrey

2013-01-01

210

Community-Based Control of Aedes aegypti By Using Mesocyclops in Southern Vietnam  

PubMed Central

We previously reported a new community-based mosquito control strategy that resulted in elimination of Aedes aegypti (Linn.) in 40 of 46 communes in northern and central Vietnam, and with annual recurrent total costs (direct and indirect) of only $0.28–$0.89 international dollars per person. This control strategy was extended to four provinces in southern Vietnam in Long An and Hau Giang (2004–2007) and to Long An, Ben Tre, and Vinh Long (2005–2010). In a total of 14 communes with 124,743 residents, the mean ± SD of adult female Ae. aegypti was reduced from 0.93 ± 0.62 to 0.06 ± 0.09, and the reduction of immature Ae. aegypti averaged 98.8%. By the final survey, no adults could be collected in 6 of 14 communes, and one commune, Binh Thanh, also had no immature forms. Although the community-based programs also involved community education and clean-up campaigns, the prevalence of Mesocyclops in large water storage containers > 50 liters increased from 12.77 ± 8.39 to 75.69 ± 9.17% over periods of 15–45 months. At the conclusion of the study, no confirmed dengue cases were detected in four of the five communes for which diagnostic serologic analysis was performed. The rate of progress was faster in communes that were added in stages to the program but the reason for this finding was unclear. At the completion of the formal project, sustainability funds were set up to provide each commune with the financial means to ensure that community-based dengue control activities continued. PMID:22556087

Nam, Vu Sinh; Yen, Nguyen Thi; Duc, Hoang Minh; Tu, Tran Cong; Thang, Vu Trong; Le, Nguyen Hoang; San, Le Hoang; Loan, Luu Le; Huong, Vu Thi Que; Khanh, Ly Huynh Kim; Trang, Huynh Thi Thuy; Lam, Leonie Z. Y.; Kutcher, Simon C.; Aaskov, John G.; Jeffery, Jason A. L.; Ryan, Peter A.; Kay, Brian H.

2012-01-01

211

Physiological and Morphological Aspects of Aedes aegypti Developing Larvae: Effects of the Chitin Synthesis Inhibitor Novaluron  

PubMed Central

Population control of the dengue vector mosquito, Aedes aegypti, is difficult due to many reasons, one being the development of resistance to neurotoxic insecticides employed. The biosynthesis of chitin, a major constituent of insect cuticle, is a novel target for population control. Novaluron is a benzoylphenylurea (BPU) that acts as a chitin synthesis inhibitor, already used against mosquitoes. However, information regarding BPU effects on immature mosquito stages and physiological parameters related with mosquito larval development are scarce. A set of physiological parameters were recorded in control developing larvae and novaluron was administered continuously to Ae. aegypti larvae, since early third instar. Larval instar period duration was recorded from third instar until pupation. Chitin content was measured during third and fourth instars. Fourth instars were processed histochemically at the mesothorax region, stained with hematoxylin and eosin (HE) for assessment of internal tissues, and labeled with WGA-FITC to reveal chitinized structures. In control larvae: i) there is a chitin content increase during both third and fourth instars where late third instars contain more chitin than early fourth instars; ii) thoracic organs and a continuous cuticle, closely associated with the underlying epidermis were observed; iii) chitin was continuously present throughout integument cuticle. Novaluron treatment inhibited adult emergence, induced immature mortality, altered adult sex ratio and caused delay in larval development. Moreover, novaluron: i) significantly affected chitin content during larval development; ii) induced a discontinuous and altered cuticle in some regions while epidermis was often thinner or missing; iii) rendered chitin cuticle presence discontinuous and less evident. In both control and novaluron larvae, chitin was present in the peritrophic matrix. This study showed quantitatively and qualitatively evidences of novaluron effects on Ae. aegypti larval development. To our knowledge, this is the first report describing histological alterations produced by a BPU in immature vector mosquitoes. PMID:22291942

Farnesi, Luana C.; Brito, Jose M.; Linss, Jutta G.; Pelajo-Machado, Marcelo; Valle, Denise; Rezende, Gustavo L.

2012-01-01

212

Comparative Genomics of Odorant Binding Proteins in Anopheles gambiae, Aedes aegypti, and Culex quinquefasciatus  

PubMed Central

About 1 million people in the world die each year from diseases spread by mosquitoes, and understanding the mechanism of host identification by the mosquitoes through olfaction is at stake. The role of odorant binding proteins (OBPs) in the primary molecular events of olfaction in mosquitoes is becoming an important focus of biological research in this area. Here, we present a comprehensive comparative genomics study of OBPs in the three disease-transmitting mosquito species Anopheles gambiae, Aedes aegypti, and Culex quinquefasciatus starting with the identification of 110 new OBPs in these three genomes. We have characterized their genomic distribution and orthologous and phylogenetic relationships. The diversity and expansion observed with respect to the Aedes and Culex genomes suggests that the OBP gene family acquired functional diversity concurrently with functional constraints posed on these two species. Sequences with unique features have been characterized such as the “two-domain OBPs” (previously known as Atypical OBPs) and “MinusC OBPs” in mosquito genomes. The extensive comparative genomics featured in this work hence provides useful primary insights into the role of OBPs in the molecular adaptations of mosquito olfactory system and could provide more clues for the identification of potential targets for insect repellants and attractants. PMID:23292137

Manoharan, Malini; Ng Fuk Chong, Matthieu; Vaitinadapoule, Aurore; Frumence, Etienne; Sowdhamini, Ramanathan; Offmann, Bernard

2013-01-01

213

The Cost of Routine Aedes aegypti Control and of Insecticide-Treated Curtain Implementation  

PubMed Central

Insecticide-treated curtains (ITCs) are promoted for controlling the Dengue vector Aedes aegypti. We assessed the cost of the routine Aedes control program (RACP) and the cost of ITC implementation through the RACP and health committees in Venezuela and through health volunteers in Thailand. The yearly cost of the RACP per household amounted to US$2.14 and $1.89, respectively. The ITC implementation cost over three times more, depending on the channel used. In Venezuela the RACP was the most efficient implementation-channel. It spent US$1.90 (95% confidence interval [CI]: 1.83; 1.97) per curtain distributed, of which 76.9% for the curtain itself. Implementation by health committees cost significantly (P = 0.02) more: US$2.32 (95% CI: 1.93; 2.61) of which 63% for the curtain. For ITC implementation to be at least as cost-effective as the RACP, at equal effectiveness and actual ITC prices, the attained curtain coverage and the adulticiding effect should last for 3 years. PMID:21540384

Baly, Alberto; Flessa, Steffen; Cote, Marilys; Thiramanus, Thirapong; Vanlerberghe, Veerle; Villegas, Elci; Jirarojwatana, Somchai; Van der Stuyft, Patrick

2011-01-01

214

Targeting gene expression to the female larval fat body of transgenic Aedes aegypti mosquitoes  

PubMed Central

As the fat body is a critical tissue for mosquito development, metamorphosis, immune and reproductive system function, characterization of regulatory modules targeting gene expression to the female mosquito fat body at distinct life stages is much needed for multiple, varied strategies for controlling vector-borne diseases such as dengue and malaria. The hexameric storage protein, Hexamerin-1.2, of the mosquito, Aedes atropalpus, is female-specific and uniquely expressed in the fat body of fourth-instar larvae and young adults. We have identified in the Hex-1.2 gene, a short regulatory module that directs female-, tissue-, and stage-specific lacZ reporter gene expression using a heterologous promoter in transgenic lines of the dengue vector, Aedes aegypti. Male transgenic larvae and pupae of one line expressed no E. coli ?-galactosidase or transgene product; in two other lines reporter gene activity was highly female-biased. All transgenic lines expressed the reporter only in the fat body. However, lacZ mRNA levels were no different in males and females at all stages examined, suggesting that the gene regulatory module drives female-specific expression by post-transcriptional regulation in the heterologous mosquito. This regulatory element from the Hex-1.2 gene thus provides a new molecular tool for transgenic mosquito control as well as functional genetic analysis in aedine mosquitoes. PMID:23241066

TOTTEN, Daniel C.; VUONG, Mai; LITVINOVA, Oksana V.; JINWAL, Umesh K.; GULIA-NUSS, Monika; HARRELL, Robert A.; BENES, Helen

2014-01-01

215

Ovicidal and repellent activities of botanical extracts against Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi (Diptera: Culicidae)  

PubMed Central

Objective To determine the ovicidal and repellent activities of methanol leaf extract of Ervatamia coronaria (E. coronaria) and Caesalpinia pulcherrima (C. pulcherrima) against Culex quinquefasciatus (Cx. quinquefasciatus), Aedes aegypti (Ae. aegypti) and Anopheles stephensi (An. stephensi). Methods The ovicidal activity was determined against three mosquito species at various concentrations ranging from 50-450 ppm under the laboratory conditions. The hatch rates were assessed 48 h after treatment. The repellent efficacy was determined against three mosquito species at three concentrations viz., 1.0, 2.5 and 5.0 mg/cm2 under the laboratory conditions. Results The crude extract of E. coronaria exerted zero hatchability (100% mortality) at 250, 200 and 150 ppm for Cx. quinquefasciatus, Ae. aegypti and An. stephensi, respectively. The crude extract of C. pulcherrima exerted zero hatchability (100% mortality) at 375, 300 and 225 ppm for Cx. quinquefasciatus, Ae. aegypti and An. Stephensi, respectively. The methanol extract of E. coronaria found to be more repellenct than C. pulcherrima extract. A higher concentration of 5.0 mg/cm2 provided 100% protection up to 150, 180 and 210 min against Cx. quinquefasciatus, Ae. aegypti and An. stephensi, respectively. The results clearly showed that repellent activity was dose dependent. Conclusions From the results it can be concluded the crude extracts of E. coronaria and C. pulcherrima are an excellent potential for controlling Cx. quinquefasciatus, Ae. aegypti and An. stephensi mosquitoes. PMID:23569723

Govindarajan, M; Mathivanan, T; Elumalai, K; Krishnappa, K; Anandan, A

2011-01-01

216

Larvicidal activity of a toxin from the seeds of Jatropha curcas Linn. against Aedes aegypti Linn. and Culex quinquefasciatus Say.  

PubMed

The larvicidal effects of the crude protein extract and purified toxin, Jc-SCRIP, from the seed coat of Jatropha curcas Linn. against the third instar larvae of mosquitoes, Aedes aegypti Linn. and Culex quinquefasciatus Say, were investigated. This test compared the effects of the purified toxin with crude protein extracts from seed kernels of J. curcas and Ricinus communis. At various concentrations of purified toxin and crude protein extract, the larval mortality of both Ae. aegypti and Cx. quinquefasciatus were positively correlated with increased exposure time. The larvae of Cx. quinquefasciatus were more susceptible to the toxin and both extracts than the larvae of Ae. aegypti. After 24 hours of exposure, the extract showed larvicidal activity against Ae. aegypti and Cx. quinquefasciatus with (LC50) values of 3.89 mg/ml and 0.0575 mg/ml, respectively. The toxin, Jc-SCRIP, showed larvicidal activity against Ae. aegypti and Cx. quinquefasciatus with (LC50) values of 1.44 mg/ml and 0.0303 mg/ ml, respectively. These results indicated that the crude protein extract and Jc-SCRIP were more toxic to the third instar larvae of Cx. quinquefasciatus than that of Ae. aegypti. The potent larvicidal activities of the seed coat extract and the Jc-SCRIP toxin from J. curcas suggest that they may be used as bioactive agents to control the mosquito population. PMID:22735851

Chanthakan, Nuchsuk; Nuanchawee, Wetprasit; Sittiruk, Roytrakul; Sunanta, Ratanapo

2012-06-01

217

Effects of a Five-Year Citywide Intervention Program To Control Aedes aegypti and Prevent Dengue Outbreaks in Northern Argentina  

Microsoft Academic Search

BackgroundDengue has propagated widely through the Americas. Most countries have not been able to maintain permanent larval mosquito control programs, and the long-term effects of control actions have rarely been documented.MethodologyThe study design was based on a before-and-after citywide assessment of Aedes aegypti larval indices and the reported incidence of dengue in Clorinda, northeastern Argentina, over 2003–2007. Interventions were mainly

Ricardo E. Gürtler; Fernando M. Garelli; Héctor D. Coto

2009-01-01

218

Water Use Practices Limit the Effectiveness of a Temephos-Based Aedes aegypti Larval Control Program in Northern Argentina  

Microsoft Academic Search

BackgroundA five-year citywide control program based on regular application of temephos significantly reduced Aedes aegypti larval indices but failed to maintain them below target levels in Clorinda, northern Argentina. Incomplete surveillance coverage and reduced residuality of temephos were held as the main putative causes limiting effectiveness of control actions.MethodologyThe duration of temephos residual effects in household-owned water-holding tanks (the most

Fernando M. Garelli; Manuel O. Espinosa; Diego Weinberg; María A. Trinelli; Ricardo E. Gürtler

2011-01-01

219

LABORATORY EVALUATION OF THE DEVELOPMENT OF Aedes aegypti IN TWO SEASONS: INFLUENCE OF DIFFERENT PLACES AND DIFFERENT DENSITIES  

PubMed Central

Aedes aegypti is an important vector in Brazil being the main vector of the dengue-fever. This paper employs survival curves to describe the time in days from larvae to adult forms of Aedes aegypti raised, individually and collectively, and compares it during winter and spring when positioned inside and outside a laboratory. The study was conducted in São Vicente, a coastal city in Southeastern Brazil. The lowest water temperature in winter and in spring was 20 °C and the highest was 26 °C in spring. Higher and more stable temperatures were measured in the intra compared to the peri in both seasons. Consequently, larvae positioned in the intra resulted in the lowest median time to develop in the individual and collective experiment (nine and ten days, respectively). At least 25% of the larvae positioned in the intra in the individual experiment in the spring took only seven days to reach adulthood. Sex ratios and the median time development by sex did not show significant differences. These results indicate that efforts to control Aedes aegypti must be continuous and directed mainly to prevent the intra-domiciliary sites that can be infested in a week in order to reduce the human-vector contact. PMID:25229215

Lopes, Tatiana Forte; Holcman, Marcia Moreira; Barbosa, Gerson Laurindo; Domingos, Maria de Fatima; Barreiros, Rosa Maria Oliveira Veiga

2014-01-01

220

Bioactivity Evaluation of Plant Extracts Used in Indigenous Medicine against the Snail, Biomphalaria glabrata, and the Larvae of Aedes aegypti  

PubMed Central

This investigation examined the molluscicidal and larvicidal activity of eight plants that are used in the traditional medicine of the Pankararé indigenous people in the Raso da Catarina region, Bahia state, Brazil. The tested plants were chosen based on the results of previous studies. Only those plants that were used either as insect repellents or to treat intestinal parasitic infections were included in the study. Crude extracts (CEs) of these plants were tested for their larvicidal activity (against Aedes aegypti larvae in the fourth instar) and molluscicidal activity (against the snail Biomphalaria glabrata). The plant species Scoparia dulcis and Helicteres velutina exhibited the best larvicidal activities (LC50 83.426?mg/L and LC50 138.896?mg/L, resp.), and Poincianella pyramidalis, Chenopodium ambrosoides, and Mimosa tenuiflora presented the best molluscicidal activities (LC50 0.94?mg/L, LC50 13.51?mg/L, and LC50 20.22?mg/L, resp.). As we used crude extracts as the tested materials, further study is warranted to isolate and purify the most active compounds. PMID:22194773

dos Santos, Edilson Alves; de Carvalho, Cenira M.; Costa, Ana L. S.; Conceicao, Adilva S.; Moura, Flavia de B. Prado; Santana, Antonio Euzebio Goulart

2012-01-01

221

Exploring new thermal fog and ultra-low volume technologies to improve indoor control of the dengue vector, Aedes aegypti (Diptera: Culicidae).  

PubMed

Control of the mosquito vector, Aedes aegypti (L.), inside human habitations must be performed quickly and efficiently to reduce the risk of transmission during dengue outbreaks. As part of abroad study to assess the efficacy of dengue vector control tools for the U.S. Military, two pesticide delivery systems (ultra-low volume [ULV] and thermal fog) were evaluated for their ability to provide immediate control of Ae. aegypti mosquitoes with a contact insecticide inside simulated urban structures. An insect growth regulator was also applied to determine how well each sprayer delivered lethal doses of active ingredient to indoor water containers for pupal control. Mortality of caged Ae. aegypti, pesticide droplet size, and droplet deposition were recorded after applications. In addition, larval and pupal mortality was measured from treated water samples for 4 wk after the applications. The ULV and the thermal fogger performed equally well in delivering lethal doses of adulticide throughout the structures. The ULV resulted in greater larval mortality and adult emergence inhibition in the water containers for a longer period than the thermal fogger. Therefore, the ULV technology is expected to be a better tool for sustained vector suppression when combined with an effective insect growth regulator. However, during a dengue outbreak, either delivery system should provide an immediate knockdown of vector populations that may lower the risk of infection and allow other suppression strategies to be implemented. PMID:25118418

Harwood, James F; Farooq, Muhammad; Richardson, Alec G; Doud, Carl W; Putnam, John L; Szumlas, Daniel E; Richardson, Jason H

2014-07-01

222

Identifying the effective concentration for spatial repellency of the dengue vector Aedes aegypti  

PubMed Central

Background Current efforts are underway to quantify the chemical concentration in a treated air space that elicits a spatial repellent (deterrent) response in a vector population. Such information will facilitate identifying the optimum active ingredient (AI) dosage and intervention coverage important for the development of spatial repellent tools – one of several novel strategies being evaluated for vector-borne disease control. This study reports initial findings from air sampling experiments conducted under field conditions to describe the relationship between air concentrations of repellent AIs and deterrent behavior in the dengue vector, Aedes aegypti. Methods Air samples were taken inside and outdoors of experimental huts located in Pu Tuey Village, Kanchanaburi Province, Thailand in conjunction with mosquito behavioral evaluations. A mark-release-recapture study design using interception traps was used to measure deterrency of Ae. aegypti against 0.00625% metofluthrin coils and DDT-treated fabric (2g/m2) within separate experimental trials. Sentinel mosquito cohorts were positioned adjacent to air sampling locations to monitor knock down responses to AI within the treated air space. Air samples were analyzed using two techniques: the U.S. Environmental Protection Agency (USEPA) Compendium Method TO-10A and thermal desorption (TD). Results Both the USEPA TO-10A and TD air sampling methods were able to detect and quantify volatized AIs under field conditions. Air samples indicated concentrations of both repellent chemicals below thresholds required for toxic responses (mortality) in mosquitoes. These concentrations elicited up to a 58% and 70% reduction in Ae. aegypti entry (i.e., deterrency) into treated experimental huts using metofluthrin coils and DDT-treated fabric, respectively. Minimal knock down was observed in sentinel mosquito cohorts positioned adjacent to air sampling locations during both chemical evaluations. Conclusions This study is the first to describe two air sampling methodologies that are appropriate for detecting and quantifying repellent chemicals within a treated air space during mosquito behavior evaluations. Results demonstrate that the quantity of AI detected by the mosquito vector, Ae. aegypti, that elicits repellency is far lower than that needed for toxicity. These findings have important implications for evaluation and optimization of new vector control tools that function through mosquito behavior modification as opposed to mortality. PMID:23273133

2012-01-01

223

High Level of Vector Competence of Aedes aegypti and Aedes albopictus from Ten American Countries as a Crucial Factor in the Spread of Chikungunya Virus  

PubMed Central

ABSTRACT Chikungunya virus (CHIKV) causes a major public health problem. In 2004, CHIKV began an unprecedented global expansion and has been responsible for epidemics in Africa, Asia, islands in the Indian Ocean region, and surprisingly, in temperate regions, such as Europe. Intriguingly, no local transmission of chikungunya virus (CHIKV) had been reported in the Americas until recently, despite the presence of vectors and annually reported imported cases. Here, we assessed the vector competence of 35 American Aedes aegypti and Aedes albopictus mosquito populations for three CHIKV genotypes. We also compared the number of viral particles of different CHIKV strains in mosquito saliva at two different times postinfection. Primarily, viral dissemination rates were high for all mosquito populations irrespective of the tested CHIKV isolate. In contrast, differences in transmission efficiency (TE) were underlined in populations of both species through the Americas, suggesting the role of salivary glands in selecting CHIKV for highly efficient transmission. Nonetheless, both mosquito species were capable of transmitting all three CHIKV genotypes, and TE reached alarming rates as high as 83.3% and 96.7% in A. aegypti and A. albopictus populations, respectively. A. albopictus better transmitted the epidemic mutant strain CHIKV_0621 of the East-Central-South African (ECSA) genotype than did A. aegypti, whereas the latter species was more capable of transmitting the original ECSA CHIKV_115 strain and also the Asian genotype CHIKV_NC. Therefore, a high risk of establishment and spread of CHIKV throughout the tropical, subtropical, and even temperate regions of the Americas is more real than ever. IMPORTANCE Until recently, the Americas had never reported chikungunya (CHIK) autochthonous transmission despite its global expansion beginning in 2004. Large regions of the continent are highly infested with Aedes aegypti and Aedes albopictus mosquitoes, and millions of dengue (DEN) cases are annually recorded. Indeed, DEN virus and CHIK virus (CHIKV) share the same vectors. Due to a recent CHIK outbreak affecting Caribbean islands, the need for a Pan-American evaluation of vector competence was compelling as a key parameter in assessing the epidemic risk. We demonstrated for the first time that A. aegypti and A. albopictus populations throughout the continent are highly competent to transmit CHIK irrespective of the viral genotypes tested. The risk of CHIK spreading throughout the tropical, subtropical, and even temperate regions of the Americas is more than ever a reality. In light of our results, local authorities should immediately pursue and reinforce epidemiological and entomological surveillance to avoid a severe epidemic. PMID:24672026

Vega-Rúa, Anubis; Zouache, Karima; Girod, Romain

2014-01-01

224

Exploring the molecular basis of insecticide resistance in the dengue vector Aedes aegypti: a case study in Martinique Island (French West Indies)  

PubMed Central

Background The yellow fever mosquito Aedes aegypti is a major vector of dengue and hemorrhagic fevers, causing up to 100 million dengue infections every year. As there is still no medicine and efficient vaccine available, vector control largely based on insecticide treatments remains the only method to reduce dengue virus transmission. Unfortunately, vector control programs are facing operational challenges with mosquitoes becoming resistant to commonly used insecticides. Resistance of Ae. aegypti to chemical insecticides has been reported worldwide and the underlying molecular mechanisms, including the identification of enzymes involved in insecticide detoxification are not completely understood. Results The present paper investigates the molecular basis of insecticide resistance in a population of Ae. aegypti collected in Martinique (French West Indies). Bioassays with insecticides on adults and larvae revealed high levels of resistance to organophosphate and pyrethroid insecticides. Molecular screening for common insecticide target-site mutations showed a high frequency (71%) of the sodium channel 'knock down resistance' (kdr) mutation. Exposing mosquitoes to detoxification enzymes inhibitors prior to bioassays induced a significant increased susceptibility of mosquitoes to insecticides, revealing the presence of metabolic-based resistance mechanisms. This trend was biochemically confirmed by significant elevated activities of cytochrome P450 monooxygenases, glutathione S-transferases and carboxylesterases at both larval and adult stages. Utilization of the microarray Aedes Detox Chip containing probes for all members of detoxification and other insecticide resistance-related enzymes revealed the significant constitutive over-transcription of multiple detoxification genes at both larval and adult stages. The over-transcription of detoxification genes in the resistant strain was confirmed by using real-time quantitative RT-PCR. Conclusion These results suggest that the high level of insecticide resistance found in Ae. aegypti mosquitoes from Martinique island is the consequence of both target-site and metabolic based resistance mechanisms. Insecticide resistance levels and associated mechanisms are discussed in relation with the environmental context of Martinique Island. These finding have important implications for dengue vector control in Martinique and emphasizes the need to develop new tools and strategies for maintaining an effective control of Aedes mosquito populations worldwide. PMID:19857255

Marcombe, Sebastien; Poupardin, Rodolphe; Darriet, Frederic; Reynaud, Stephane; Bonnet, Julien; Strode, Clare; Brengues, Cecile; Yebakima, Andre; Ranson, Hilary; Corbel, Vincent; David, Jean-Philippe

2009-01-01

225

Human Antibody Response to Aedes aegypti Saliva in an Urban Population in Bolivia: A New Biomarker of Exposure to Dengue Vector Bites  

PubMed Central

Aedes mosquitoes are important vectors of re-emerging diseases in developing countries, and increasing exposure to Aedes in the developed world is currently a source of concern. Given the limitations of current entomologic methods, there is a need for a new effective way for evaluating Aedes exposure. Our objective was to evaluate specific antibody responses to Aedes aegypti saliva as a biomarker for vector exposure in a dengue-endemic urban area. IgG responses to saliva were strong in young children and steadily waned with age. Specific IgG levels were significantly higher in persons living in sites with higher Ae. aegypti density, as measured by using entomologic parameters. Logistic regression showed a significant correlation between IgG to saliva and exposure level, independently of either age or sex. These results suggest that antibody responses to saliva could be used to monitor human exposure to Aedes bites. PMID:22848099

Doucoure, Souleymane; Mouchet, Francois; Cournil, Amandine; Le Goff, Gilbert; Cornelie, Sylvie; Roca, Yelin; Giraldez, Mabel Guerra; Simon, Zaira Barja; Loayza, Roxanna; Misse, Dorothee; Flores, Jorge Vargas; Walter, Annie; Rogier, Christophe; Herve, Jean Pierre; Remoue, Franck

2012-01-01

226

Larvicidal potential of silver nanoparticles synthesized from Leucas aspera leaf extracts against dengue vector Aedes aegypti.  

PubMed

Vector-borne diseases caused by mosquitoes are one of the major economic and health problems in many countries. The Aedes aegypti mosquito is a vector of several diseases in humans like yellow fever and dengue. Vector control methods involving the use of chemical insecticides are becoming less effective due to development of insecticides resistance, 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 nontoxic, easily available at affordable prices, biodegradable, and show broad-spectrum target-specific activities against different species of vector mosquitoes. Today, nanotechnology is a promising research domain which has wide-ranging application vector control programs. The present study investigates the larvicidal potential of solvent leaf extracts of Leucas aspera and synthesized silver nanoparticles using aqueous leaf extract against fourth instar larvae of Aedes aegypti. Larvae were exposed to varying concentrations of plant extracts and synthesized AgNPs for 24 h. The results were recorded from UV-Vis spectra, x-ray diffraction (XRD), Fourier transform infrared (FT-IR), and scanning electron microscopy (SEM), and were used to characterize and support the biosynthesis of silver nanoparticles. The formation of the AgNPs synthesized from the XRD spectrum compared with Bragg reflections can be indexed to the (111) orientations, respectively, confirmed the presence of AgNPs. The FT-IR spectra of AgNPs exhibited prominent peaks at 3,447.77; 2,923.30; and 1,618.66 cm(-1). The spectra showed sharp and strong absorption band at 1,618.66 cm(-1) assigned to the stretching vibration of (NH) C?O group. The band 1,383 developed for C?C and C?N stretching, respectively, and was commonly found in the proteins. SEM analysis of the synthesized AgNPs clearly showed the clustered and irregular shapes, mostly aggregated, and having the size of 25-80 nm. Energy-dispersive x-ray spectroscopy showed the complete chemical composition of the synthesized AgNPs. In larvicidal activity, the results showed that the maximum efficacy was observed in synthesized AgNPs leaf extracts against the fourth instar larvae of A. aegypti (LC50 values of 8.5632, 10.0361, 14.4689, 13.4579, 17.4108, and 27.4936 mg/l) and (LC90 values of 21.5685, 93.03928, 39.6485, 42.2029, 31.3009, and 53.2576 mg/l), respectively. These results suggest that the synthesized AgNPs leaf extracts have a higher larvicidal potential as compared to crude solvent extracts thus making them an effective combination for controlling A. aegypti. PMID:24553980

Suganya, Ganesan; Karthi, Sengodan; Shivakumar, Muthugounder S

2014-05-01

227

Larvicidal and pupicidal activities of essential oils from Zingiberaceae plants against Aedes aegypti (Linn.) and Culex quinquefasciatus say mosquitoes.  

PubMed

We conducted this study to investigate the efficacy of herbal essential oils from 12 species of Zingiberaceae plants to determine their larvicidal and pupicidal activity against fourth instar larvae and pupae of Aedes aegypti and Culex quinquefasciatus mosquitoes. Probit analysis was used to analyze the data. Larval mortality was recorded at 1, 5, 10, 15, 30 and 60 minutes and 24 hours. Pupal mortality was recorded at 15 and 30 minutes and 1, 3, 6, 12, 24 and 48 hours. All the essential oils tested showed larvicidal activity. Zingiber cassumunar and Amomum biflorum oils proved to have the greatest activity against Ae. aegypti larvae with LT50 of 1.4 minutes and 100% mortality at 5 and 10 minutes, respectively. Boesenbergia rotunda, Curcuma zedoaria and Hedychium coronarium essential oils had activity against Cx. quinquefasciatus larvae with LT50 of 1.7 minutes and 100% mortality at 10 minutes, 5 minutes and 15 minutes, respectively. All the herbal essential oils tested resulted in 100% mortality against Ae. aegypti and Cx. quinquefasciatus larvae at 60 minutes and 30 minutes, respectively. Ae. aegypti and Cx. quinquefasciatus pupae were susceptible to Z. ottensii oil (LT50 of 0.2 hour) and Z. zerumbet oil (LT50 of 0.6 hour) and had pupicidal activity with 100% mortality at 6 and 3 hours, respectively. All the essential oils test had pupicidal activity against Ae. aegypti and Cx. quinquefasciatus by inducing 100% mortality at 48 hours. PMID:24437311

Phukerd, Ubol; Soonwera, Mayura

2013-09-01

228

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

PubMed Central

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

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

2011-01-01

229

Seasonal changes in the larvel populations of Aedes aegypti in two biotopes in Dar es Salaam, Tanzania  

PubMed Central

The seasonal dynamics of larval populations of Aedes aegypti was studied in two different biotopes in Dar es Salaam, Tanzania. The first biotope was located on the Msasani peninsula on the coast 6 km north of Dar es Salaam, where A. aegypti breeds exclusively in coral rock holes. The population dynamics was studied during both the rainy and the dry season. Seasonal changes in the density of A. aegypti larvae depend primarily on variation in rainfall. The population of larvae dropped to zero only for a short time during the driest period while the adult population was maintained at a low level. The second biotope was in an automobile dump in a Dar es Salaam suburb, where A. aegypti breeds in artificial containers such as tires, automobile parts, tins, coconut shells, and snail shells. The greater part of the A. aegypti population of this biotope is maintained in the egg stage during the dry season. It serves as a focal point for breeding during the dry season: with the coming of the rains, the population expands into the surrounding residential areas. More than 70% of the larval population developed in tires, 20% in tins, 5% in coconut shells, and 1% in snail shells. PMID:4539415

Trpis, Milan

1972-01-01

230

Modeling the Non-Stationary Climate Dependent Temporal Dynamics of Aedes aegypti  

PubMed Central

Background Temperature and humidity strongly affect the physiology, longevity, fecundity and dispersal behavior of Aedes aegypti, vector of dengue fever. Contrastingly, the statistical associations measured between time series of mosquito abundance and meteorological variables are often weak and contradictory. Here, we investigated the significance of these relationships at different time scales. Methods and Findings A time series of the adult mosquito abundance from a medium-sized city in Brazil, lasting 109 weeks was analyzed. Meteorological variables included temperature, precipitation, wind velocity and humidity. As analytical tools, generalized linear models (GLM) with time lags and interaction terms were used to identify average effects while the wavelet analysis was complementarily used to identify transient associations. The fitted GLM showed that mosquito abundance is significantly affected by the interaction between lagged temperature and humidity, and also by the mosquito abundance a week earlier. Extreme meteorological variables were the best predictors, and the mosquito population tended to increase at values above and 54% humidity. The wavelet analysis identified non-stationary local effects of these meteorological variables on abundance throughout the study period, with peaks in the spring-summer period. The wavelet detected weak but significant effects for precipitation and wind velocity. Conclusion Our results support the presence of transient relationships between meteorological variables and mosquito abundance. Such transient association may be explained by the ability of Ae. aegypti to buffer part of its response to climate, for example, by choosing sites with proper microclimate. We also observed enough coupling between the abundance and meteorological variables to develop a model with good predictive power. Extreme values of meteorological variables with time lags, interaction terms and previous mosquito abundance are strong predictors and should be considered when understanding the climate effect on mosquito abundance and population growth. PMID:23976939

Simoes, Taynana C.; Codeco, Claudia T.; Nobre, Aline A.; Eiras, Alvaro E.

2013-01-01

231

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

PubMed

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 (?-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

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

2014-07-01

232

Bioactivity of seagrass against the dengue fever mosquito Aedes aegypti larvae  

PubMed Central

Objective To identify the larvicidal activity of the seagrass extracts. Methods Seagrass extracts, Syringodium isoetifolium (S. isoetifolium), Cymodocea serrulata and Halophila beccarii, were dissolved in DMSO to prepare a graded series of concentration. Batches of 25 early 4th instars larvae of Aedes aegypti (Ae. aegypti) were transferred to 250 mL enamel bowl containing 199 mL of distilled water and 1 mL of plant extracts (0.01 mg – 0.1 mg). After 24 h the mortality rate was identified with the formulae [(% of test mortality – % of control mortality)/(100 – % of control mortality)] × 100. Each experiment was conducted with three replicates and a concurrent control group. A control group consisted of 1 mL of DMSO and 199 mL of distilled water only. Results : The root extract of S. isoetifolium showed maximum larvicidal activity with minimum concentration of extract of LC50= 0.0?604 ± 0.0?040)µg/mL with lower confidence limit (LCL) – upper confidence limit (UCL) = (0.051–0.071) and LC90=0.0?972µg/mL followed by leaf extract of S. isoetifolium showed LC50= (0.062 ± 0.005)µg/mL. The regression equation of root and leaf extract of S. isoetifolium for 4th instar larvae were Y= 4.909 + 1.32x (R2= 0.909) and Y= 2.066 + 1.21x (R2 =0.897) respectively. The results of the preliminary phytochemical constituents shows the presence of saponin, steroids, terpenoid, phenols, protein and sugars. Conclusions From the present study the ethanolic extracts of seagrass of S. isoetifolium possesses lead compound for development of larvicidal activity. PMID:23569973

Ali, M Syed; Ravikumar, S; Beula, J Margaret

2012-01-01

233

Adulticidal and repellent properties of indigenous plant extracts against Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae).  

PubMed

Several diseases are associated to the mosquito-human interaction. Mosquitoes are the carriers of severe and well-known illnesses such as malaria, arboviral encephalitis, dengue fever, chikunguniya fever, West Nile virus, and yellow fever. These diseases produce significant morbidity and mortality in humans and livestock around the world. The adulticidal and repellent activities of crude hexane, ethyl acetate, benzene, chloroform, and methanol extracts of leaf of Eclipta alba and Andrographis paniculata were assayed for their toxicity against two important vector mosquitoes, viz., Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae). The adult mortality was observed after 24 h of exposure. All extracts showed moderate adulticide effects; however, the highest adult mortality was found in methanol extract of A. paniculata against the adults of C. quinquefasciatus and A. aegypti with the LC(50) and LC(90) values were 149.81, 172.37 ppm and 288.12, 321.01 ppm, respectively. The results of the repellent activity of hexane, ethyl acetate, benzene, chloroform, and methanol extract of E. alba and A. paniculata plants at three different concentrations of 1.0, 2.5, and 5.0 mg/cm(2) were applied on skin of forearm in man and exposed against adult female mosquitoes. In this observation, these two plant crude extracts gave protection against mosquito bites without any allergic reaction to the test person, and also, the repellent activity is dependent on the strength of the plant extracts. These results suggest that the leaf solvent plant extracts have the potential to be used as an ideal ecofriendly approach for the control of mosquitoes. This is the first report on the mosquito adulticidal and repellent activities of the reported E. alba and A. paniculata plants. PMID:22009267

Govindarajan, Marimuthu; Sivakumar, Rajamohan

2012-05-01

234

Insecticide resistance status of Aedes aegypti in 10 localities in Colombia.  

PubMed

Insecticide resistance is one of the major threats to the effectiveness of vector control programs. In order to establish a baseline susceptibility profile of Aedes aegypti in the southwest of Colombia, 10 localities in four Departments (States) were evaluated. Standardized WHO bioassay, CDC bottle bioassay and microplate biochemical assays of non-specific ?-esterase (NSE), mixed function oxidases (MFO) and acetylcholinesterase were used. Cross resistance was evaluated with field collected mosquitoes that underwent selection pressure in the laboratory from DDT, propoxur and lambdacyhalothrin during three alternate generations. Mosquitoes with mortality rates below 80% in bioassays were considered resistant. Insecticide resistance varied geographically. Insecticide resistance was observed in 100% of localities in which mosquitoes were exposed to DDT, bendiocarb and temephos using both assays. WHO bioassays showed susceptibility to pyrethroids in all the localities evaluated, however CDC bottle bioassays showed decreases in susceptibility especially with lambdacyhalothrin. All localities showed susceptibility to the organophosphate malathion. Mosquitoes from eight regions with evidence of resistance to any of the insecticide evaluated were also evaluated biochemically. Mosquitoes from five of these regions had increased levels of NSE and two regions had increased levels of MFO. Increase levels of NSE explain partially the low susceptibility to temephos found in all the localities. However, the biochemical mechanisms evaluated do not explain all the resistance observed. Cross resistance was observed between the DDT-selected strain and lambdacyhalothrin, and between the lambdacyhalothrin-selected strain and propoxur and vice versa. The selected strains do not show changes in the biochemical assays evaluated, therefore the observed cross-resistance suggests different biochemical mechanisms. This study shows that Ae. aegypti from Colombia can develop resistance to most of the insecticide classes in the market. Periodic surveillance of insecticide resistance is necessary in order to maintain effective interventions. This study helped to establish the National Network for the surveillance of the insecticide resistance in Colombia. PMID:21300017

Ocampo, Clara B; Salazar-Terreros, Myriam J; Mina, Neila J; McAllister, Janet; Brogdon, William

2011-04-01

235

Aedes aegypti pharate 1st instar quiescence affects larval fitness and metal tolerance  

PubMed Central

The eggs of the mosquito Aedes aegypti possess the ability to undergo an extended quiescence hosting a fully developed 1st instar larvae within the chorion. As a result of this life history traitpharate larvae can withstand months of quiescence inside the egg where they depend on stored maternal reserves. A. aegypti mosquitoes are frequently associated with urban habitats that may contain significant metal pollution. Therefore, the duration of quiescence and extent of nutritional depletion may affect the physiology and survival of larvae that hatch in a suboptimal habitat. The aim of this study was to determine the effect of an extended quiescence on larval nutrient reserves and the subsequent effects of metal exposure on larval fitness, survival and development. We hypothesized that an extended quiescence would reduce nutritional reserves and alter the molecular response to metal exposure thereby reducing larval survival and altering larval development. As a molecular marker for metal stress responses, we evaluated transcriptional changes in the metallothionein gene (AaMtn) in response to quiescence and metal exposure. Extended 1st instar quiescence resulted in a significant decrease in lipid reserves and negatively affected larval fitness and development. AaMtn transcription and metal tolerance were compromised in first instars emerged from eggs that had undergone an extended quiescence. These findings suggest that newly emerged mosquito larvae that had survived a relatively long pharate 1st instar quiescence (as might occur during a dry season) are more vulnerable to environmental stress. Pharate 1st instar quiescence could have implications for vector control strategies. Newly emerged mosquito larvae at the end of the dry season or start of the wet season are physiologically compromised, and therefore potentially more susceptible to vector control strategies than mosquito larvae hatched subsequently throughout the wet season. PMID:22426084

Perez, Mario H.; Noriega, Fernando G.

2012-01-01

236

eVALUACiÓn deL eFeCto ReSidUAL deL teMePHoS en LARVAS de Aedes aegypti en LiMA, PeRÚ  

Microsoft Academic Search

ReSUMen El temephos ha sido usado como la única estrategia de control para Aedes aegypti en Lima durante los últimos años. Objetivo: EvaluarlaeficaciaresidualdetemephosparaelcontroldeAe. aegypti en condiciones de campo y laborato- rio en Lima, Perú. Materiales y métodos: Se eligieron ocho tanques bajos de concreto (TBC) depósitos predominan- temente infestados con Ae. aegypti en el distrito de San Juan de Lurigancho,

Miriam Palomino S; Lely Solari; Walter León C; Rosario Vega H; Máximo Vergaray C; Luis Cubillas; Rosa Mosqueda C; Norma García A

237

Characterization of insecticide resistance in Trinidadian strains of Aedes aegypti mosquitoes.  

PubMed

Bioassays and biochemical assays were conducted on eight Trinidadian strains of Aedes aegypti larvae to determine the involvement of biochemical mechanisms in resistance to insecticides. Larval strains were assayed to dichlorodiphenyltrichloroethane (DDT), bendiocarb, temephos and permethrin, using the Centers for Disease Control and Prevention (CDC) time-mortality bioassay method. A Resistance Threshold (RT) was calculated for each insecticide in relation to the CAREC reference susceptible Ae. aegypti strain and larval strains with <80% mortality were considered to be resistant. Biochemical assays were performed to determine the activities of nonspecific esterases (?- and ?-), PNPA-esterases, mixed function oxidases (MFO), glutathione-S-transferases (GST) and acetylcholinesterase (AChE) enzymes which are involved in insecticide resistance in mosquitoes. Enzyme profiles of each strain were compared with those of the CAREC reference susceptible strain by Kruskal-Wallis and Dunn's multiple comparison tests (p<0.05). The CAREC 99th percentile was calculated for each enzyme and the percentage of individuals with enzyme activities above that of the CAREC 99th percentile was calculated. Activities were classified as unaltered (<50%), incipiently altered (15-50%) or altered (>50%) for each strain. The established RTs for permethrin and bendiocarb were 30 and 75 min, respectively; and 120 min for DDT and temephos. All strains were resistant to DDT (1.00-40.25% mortality) and temephos (11.50-74.50% mortality) while six strains were resistant to bendiocarb (51.50-78.50% mortality) and five to permethrin (6.50-42.50% mortality). Biochemical assays revealed that the median activity levels for all enzymes varied significantly (p<0.05). The Curepe strain had incipiently altered levels of ?-esterase while the other seven strains had altered activity with five of them registering 100%. The St Clair strain showed altered activity levels of ?-esterase while three strains had incipiently altered levels. The majority of strains had altered activity of MFO enzymes but only the St Clair strain showed altered activity of GST. PNPA-esterases activity was unaltered in all strains and only the Haleland Park strain showed altered remaining AChE activity in the presence of propoxur. Elevated levels of enzymes (incipiently altered or altered), except in the case of PNPA-esterases, show that biochemical resistance may play an important role in the manifestation of insecticide resistance in Trinidadian populations of Ae. aegypti. It is therefore important for insecticide resistance surveillance to be ongoing as the detection of resistance before it spreads throughout an entire population makes it possible for early intervention. PMID:20858454

Polson, Karen A; Brogdon, William G; Rawlins, Samuel C; Chadee, Dave D

2011-01-01

238

Transinfected Wolbachia have minimal effects on male reproductive success in Aedes aegypti  

PubMed Central

Background Wolbachia are maternally inherited endosymbiotic bacteria that manipulate the reproductive success of their insect hosts. Uninfected females that mate with Wolbachia infected males do not reproduce due to cytoplasmic incompatibility (CI). CI results in the increased frequency of Wolbachia-infected individuals in populations. Recently, two Wolbachia strains, the benign wMel and virulent wMelPop have been artificially transinfected into the primary vector of dengue virus, the mosquito Ae. aegypti where they have formed stable infections. These Wolbachia infections are being developed for a biological control strategy against dengue virus transmission. While the effects of Wolbachia on female Ae. aegypti have been examined the effects on males are less well characterised. Here we ascertain and compare the effects of the two strains on male fitness in resource-limited environments that may better approximate the natural environment. Methods A series of population mating trials were conducted to examine the effect of Wolbachia infection status (with strains wMel and wMelPop) and male larval nutrition on insemination frequency, remating rates, the fecundity of females, the hatch rates of eggs and the wing length and fertility of males. Results wMel and wMelPop infections reduce the fecundity of infected females and wMelPop reduces the viability of eggs. Low nutrition diets for males in the larval phase affects the fecundity of wMel-infected females. Neither strain of Wolbachia affected sperm quality or viability or the ability of males to successfully mate multiple females. Conclusions The benign strain of Wolbachia, wMel causes similar reductions in fecundity as the more virulent, wMelPop, and neither are too great that they should not still spread given the action of CI. The ability of Wolbachia-infected males to repeat mate as frequently as wildtype mosquitoes indicates that they will be very good agents of delivering CI in field release populations. PMID:23399027

2013-01-01

239

[Pathogenic effect of the nematode parasite Romanomermis iyengari(Nematoda: Mermithidae) in Aedes aegypti mosquito larvae (Diptera: Culicidae) under laboratory conditions in the state of Oaxaca, Mexico].  

PubMed

Laboratory tests with waters from Aedes aegypti Linneaus (1762) breeding places were made to determine the pathogenic effect of the mermithid nematode Romanomermis iyengari Welch 1964 in mosquito larvae of this species. According to the results obtained, the administration of a dosage of 10:1 (10 preparasitics per mosquito larvae) showed levels of parasitism of 90, 93, 91, and 85% in mosquito larvae in the I, II, III, and IV stage, respectively. With the highest dosage of 20:1 (20 preparasitics per mosquito larvae) there were obtained levels of parasitism with values of 98, 97, 93 and 89% among larvae in the I, II, III, and IV stage, respectively. Generally, the values of the physical and chemical parameters such as pH, conductivity, oxygen, and chlorides calculated in these waters did not affect apparently the infective capacity of the preparasitics of R. iyengari. PMID:9842260

Santamarina Mijares, A; Pérez Pacheco, M C

1998-01-01

240

Fitness of transgenic mosquito Aedes aegypti males carrying a dominant lethal genetic system.  

PubMed

OX513A is a transgenic strain of Aedes aegypti engineered to carry a dominant, non-sex-specific, late-acting lethal genetic system that is repressed in the presence of tetracycline. It was designed for use in a sterile-insect (SIT) pest control system called RIDL® (Release of Insects carrying a Dominant Lethal gene) by which transgenic males are released in the field to mate with wild females; in the absence of tetracycline, the progeny from such matings will not survive. We investigated the mating fitness of OX513A in the laboratory. Male OX513A were as effective as Rockefeller (ROCK) males at inducing refractoriness to further mating in wild type females and there was no reduction in their ability to inseminate multiple females. They had a lower mating success but yielded more progeny than the wild-type comparator strain (ROCK) when one male of each strain was caged with a ROCK female. Mating success and fertility of groups of 10 males-with different ratios of RIDL to ROCK-competing for five ROCK females was similar, but the median longevity of RIDL males was somewhat (18%) lower. We conclude that the fitness under laboratory conditions of OX513A males carrying a tetracycline repressible lethal gene is comparable to that of males of the wild-type comparator strain. PMID:23690948

Massonnet-Bruneel, Blandine; Corre-Catelin, Nicole; Lacroix, Renaud; Lees, Rosemary S; Hoang, Kim Phuc; Nimmo, Derric; Alphey, Luke; Reiter, Paul

2013-01-01

241

Aedes aegypti TMOF modulates ecdysteroid production by prothoracic glands of the gypsy moth, Lymantria dispar.  

PubMed

Trypsin modulating oostatic factor (TMOF) is a decapeptide that inhibits the biosynthesis of trypsin-like enzymes in the midgut of several insect species and, as such, serves as a dipteran oostatic hormone. In vitro incubation of lepidopteran prothoracic glands with Aedes aegypti TMOF revealed that this decapeptide, in the presence of brain extract, modulates ecdysteroid production. The modulatory effect was highly dependent on both the concentration of TMOF and brain extract. Typically, TMOF was stimulatory in the presence of lower concentrations of Lymantria dispar brain extract (0.01 and 0. 025 brain equivalent), and either neutral or inhibitory at higher concentrations (0.25, 0.5, and 1.0 brain equivalent) of extract. In the presence of European corn borer (Ostrinia nubilalis) brain extract, TMOF also exhibited modulatory effects, effects that again were dependent on the concentrations of both brain extract and TMOF present in the incubation medium. At 1.5 brain equivalents, TMOF was inhibitory at all but the highest concentration tested (5x10(-6) M), at 1.0 brain equivalent, TMOF was stimulatory at 10(-6) M and at 0. 5 brain equivalents, TMOF did not significantly affect PTG synthesis of ecdysteroids. Results suggest the presence of a modulatory peptide(s), which fine tunes the synthesis and release of ecdysteroids by PTGs in accordance with the insect's developmental/physiological requirements. PMID:11093243

Gelman, D B; Borovsky, D

2000-10-01

242

Effects of Croton rhamnifolioides Essential Oil on Aedes aegypti Oviposition, Larval Toxicity and Trypsin Activity.  

PubMed

Although numerous reports are available concerning the larvicidal potential of essential oils, very few investigations have focused on their mechanisms of action. In the present study, we have investigated the chemical composition of the leaf oil of Croton rhamnifolioides during storage and its effects on oviposition and survival of larvae of the dengue fever mosquito Aedes aegypti. In addition, we have established a possible mechanism of action for the larvicidal activity of the essential oil. GC-MS analyses revealed marked differences in the composition of oil that had been freshly isolated and that of a sample that had been stored in a sealed amber-glass vial under refrigeration for three years. However, both fresh and stored oil exhibited substantial larvicidal activities with LC50 values of 122.35 and 89.03 ppm, respectively, and oviposition deterrent effects against gravid females at concentrations of 50 and 100 µg·mL-1. These results demonstrate that the larvicidal effect of the essential oil was unchanged during three years of storage even though its chemical composition altered. Hence, the essential oil could be used in the preparation of commercial products. In addition, we observed that the trypsin-like activity of mosquito larvae was inhibited in vitro by the essential oil of C. rhamnifolioides, suggesting that the larvicidal effect may be associated with inhibition of this enzyme. PMID:25317582

Santos, Geanne K N; Dutra, Kamilla A; Lira, Camila S; Lima, Bheatriz N; Napoleão, Thiago H; Paiva, Patrícia M G; Maranhão, Claudia A; Brandão, Sofia S F; Navarro, Daniela M A F

2014-01-01

243

Toxicity and synergic repellency of plant essential oil mixtures with vanillin against Aedes aegypti (Diptera: Culicidae).  

PubMed

In all triplicate tests of six plant essential oils and of vanillin mixtures, we corroborated strong insecticidal and repellent activities against adult Aedes aegypti (L.). Essential oils with potent toxic fumigant activities also exhibited repellency. Compared with N, N-diethyl-3-methylbenzamide, 5% of the essential oil concentrations of cassia, lemongrass, lemon eucalyptus, and xanthoxylum oils did not show repellent effects. However, a composition oflemongrass oil, xanthoxylum oil, and vanillin (1:3:1, vol:vol:wt) provided 270 min of complete protection time (CPT) compared with 247.5 min CPT with 15% N, N-diethyl-3-methylbenzamide. The CPT depended on concentration, presence ofvanillin, or on both factors. When we applied a mixture of lemongrass oil: xanthoxylum oil: vanillin (1:1:1, vol:vol:wt) to the Viscopearl formulation, or porous cellulose beads, it provided gradual release of volatile compounds, thus showing >90% of repellency for 2 h. The behavioral and electrophysiological approaches we drew upon in our current study demonstrated that plant essential oil mixtures combined with vanillin showed strong and durable repellency to the mosquito. We claim that such combinations of plant essential oils and vanillin found in current study propose a viable commercial product suitable for future application in protecting a person from mosquito bites. PMID:22897048

Kim, Soon-Il; Yoon, June-Sun; Baeck, Seung-Jae; Lee, Sung-Hwa; Ahn, Young-Joon; Kwon, Hyung Wook

2012-07-01

244

Isolation and characterization of brush border membrane vesicles from whole Aedes aegypti larvae.  

PubMed

Studies of the binding interactions of dipteran-specific Bacillus thuringiensis delta-endotoxins are hindered by the lengthy midgut dissection procedure needed for preparation of brush border membrane vesicles. In an attempt to resolve this problem, brush border membrane vesicles were isolated from homogenates of whole Aedes aegypti larvae by a modification of the method of MacIntosh et al. (1994). These preparations were found to resolve well on SDS-PAGE and appeared as spherical vesicles of various sizes under electron microscopic examination. Specific activities of the brush border membrane marker enzymes alkaline phosphatase and leucine amino acid arylamidase were enriched 10.9- and 10.7-fold, respectively. Direct binding experiments using 35S-labeled B. thuringiensis CryIC toxin revealed a single class of high-affinity binding sites with a dissociation constant (Kd) of 27 +/- 0.6 nM and a maximum binding capacity (Bmax) of approximately 27 +/- 1.2 pmol/mg BBMV protein. These binding parameters are similar to those of vesicles prepared from isolated midguts, indicating that whole larval brush border membrane vesicles are suitable for in vitro membrane binding studies. PMID:9878289

Abdul-Rauf, M; Ellar, D J

1999-01-01

245

Spatial analysis of Aedes aegypti immatures in Northern Argentina: clusters and temporal instability.  

PubMed

The objective of this study was to analyze the spatio-temporal patterns of Aedes aegypti immatures based on four entomological surveys that inspected over 6000 households in a large neighborhood of the city of Clorinda between 2007 and 2008. Global and local spatial point pattern analyses of immature presence or absence, habitat quality (estimated using a previously obtained statistical model) and pupal production were performed. Global analyses showed aggregation of both infestation and habitat quality up to 10 times bigger than previously described, ranging from 150 to 400m between surveys. Pupal production was also clustered but at smaller scales than infestation presence/absence. The location of the clusters was temporally unstable between surveys. There was no spatial structure related to the control strategy; lots treated with temephos and lots uninspected (i.e., closed or refusing) were randomly distributed. These results suggest a combination of exogenous (the aggregation of better quality habitats) and endogenous (dispersal) processes explaining the observed patterns of larger-scale infestation. A spatial targeting strategy at the neighborhood scale would not be as cost-effective in Clorinda as in other sites where stable smaller-scale clusters permit the identification of key premises. PMID:23911331

Garelli, Fernando M; Espinosa, Manuel O; Gürtler, Ricardo E

2013-12-01

246

Studies on repellent activity of seed oils alone and in combination on mosquito, Aedes aegypti.  

PubMed

The study was undertaken to investigate the relative repellency of Pongamia pinnata and Azadirachta indica seed oils on vector mosquito, Aedes aegypti under laboratory conditions. The repellents were formulated into 3 groups: seed oils, their mixture and combination of seed oils with three carrier oils viz. olive, mustard and coconut oil. Different formulations of each oil were tested at the concentrations of 1% and 5% on human baits. Efficiency was assessed, based on the total protection time; biting rate and percent protection provided by each formulation. Results showed that 5% formulation of the Pongamia pinnata and Azadirachta indica seed oils, mixed in 1:1 ratio exhibited highest percentage repellency of 85%, protection time of 300 min and bite rate of 6%. 5% concentration of A. indica and P. pinnata seed oil in mustard oil base offered 86.36% and 85% protection respectively with total protection time of 230 and 240 min respectively. The study confirms that Azadirachta indica and Pongamia pinnata have mosquito-repellent potential. When mixed in different ratios or with some carrier oil their efficacy increases 2-fold in some cases. These formulations are very promising for topical use (> 5 hrs complete protection) and are comparable to the protection provided by advanced Odomos mosquito repellent cream available commercially and thus are recommended for field trial. PMID:25204067

Mukesh, Y; Savitri, P; Kaushik, R; Singh, N P

2014-09-01

247

Larvicidal Activity against Aedes aegypti and Molluscicidal Activity against Biomphalaria glabrata of Brazilian Marine Algae.  

PubMed

This study investigated the biological activities of five benthic marine algae collected from Northeastern Region of Brazil. The tested activities included larvicidal activity against Aedes aegypti, molluscicidal activity against Biomphalaria glabrata, and toxicity against Artemia salina. Extracts of Ulva lactuca (Chlorophyta), Padina gymnospora, Sargassum vulgare (Phaeophyta), Hypnea musciformis, and Digenea simplex (Rhodophyta) were prepared using different solvents of increasing polarity, including dichloromethane, methanol, ethanol, and water. Of the extracts screened, the dichloromethane extracts of H. musciformis and P. gymnospora exhibited the highest activities and were subjected to bioassay-guided fractionation in hexane and chloroform. The chloroform fractions of the P. gymnospora and H. musciformis extracts showed molluscicidal activity at values below 40? ? g·mL(-1) (11.1460? ? g·mL(-1) and 25.8689? ? g·mL(-1), resp.), and the chloroform and hexane fractions of P. gymnospora showed larvicidal activity at values below 40? ? g·mL(-1) (29.018? ? g·mL(-1) and 17.230? ? g·mL(-1), resp.). The crude extracts were not toxic to A. salina, whereas the chloroform and hexane fractions of P. gymnospora (788.277? ? g·mL(-1) and 706.990? ? g·mL(-1)) showed moderate toxicity, indicating that the toxic compounds present in these algae are nonpolar. PMID:24688787

Guedes, Elíca Amara Cecília; de Carvalho, Cenira M; Ribeiro Junior, Karlos Antonio Lisboa; Lisboa Ribeiro, Thyago Fernando; de Barros, Lurdiana Dayse; de Lima, Maria Raquel Ferreira; Prado Moura, Flávia de Barros; Goulart Sant'ana, Antônio Euzebio

2014-01-01

248

Larvicidal Activity against Aedes aegypti and Molluscicidal Activity against Biomphalaria glabrata of Brazilian Marine Algae  

PubMed Central

This study investigated the biological activities of five benthic marine algae collected from Northeastern Region of Brazil. The tested activities included larvicidal activity against Aedes aegypti, molluscicidal activity against Biomphalaria glabrata, and toxicity against Artemia salina. Extracts of Ulva lactuca (Chlorophyta), Padina gymnospora, Sargassum vulgare (Phaeophyta), Hypnea musciformis, and Digenea simplex (Rhodophyta) were prepared using different solvents of increasing polarity, including dichloromethane, methanol, ethanol, and water. Of the extracts screened, the dichloromethane extracts of H. musciformis and P. gymnospora exhibited the highest activities and were subjected to bioassay-guided fractionation in hexane and chloroform. The chloroform fractions of the P. gymnospora and H. musciformis extracts showed molluscicidal activity at values below 40??g·mL?1 (11.1460??g·mL?1 and 25.8689??g·mL?1, resp.), and the chloroform and hexane fractions of P. gymnospora showed larvicidal activity at values below 40??g·mL?1 (29.018??g·mL?1 and 17.230??g·mL?1, resp.). The crude extracts were not toxic to A. salina, whereas the chloroform and hexane fractions of P. gymnospora (788.277??g·mL?1 and 706.990??g·mL?1) showed moderate toxicity, indicating that the toxic compounds present in these algae are nonpolar. PMID:24688787

Guedes, Elica Amara Cecilia; de Carvalho, Cenira M.; Ribeiro Junior, Karlos Antonio Lisboa; Lisboa Ribeiro, Thyago Fernando; de Barros, Lurdiana Dayse; de Lima, Maria Raquel Ferreira; Prado Moura, Flavia de Barros; Goulart Sant'Ana, Antonio Euzebio

2014-01-01

249

Pinpointing P450s Associated with Pyrethroid Metabolism in the Dengue Vector, Aedes aegypti: Developing New Tools to Combat Insecticide Resistance  

Microsoft Academic Search

BackgroundPyrethroids are increasingly used to block the transmission of diseases spread by Aedes aegypti such as dengue and yellow fever. However, insecticide resistance poses a serious threat, thus there is an urgent need to identify the genes and proteins associated with pyrethroid resistance in order to produce effective counter measures. In Ae. aegypti, overexpression of P450s such as the CYP9J32

Bradley J. Stevenson; Patricia Pignatelli; Dimitra Nikou; Mark J. I. Paine

2012-01-01

250

Repellency of essential oils of Cryptomeria japonica (Pinaceae) against adults of the mosquitoes Aedes aegypti and Aedes albopictus (Diptera:Culicidae).  

PubMed

The purpose of this study was to investigate the repellent activities of essential oils from Cryptomeria japonica (sugi) against adults of mosquitoes Aedes aegypti and Aedes albopictus . Comparison of essential oils from four different plant parts of C. japonica revealed that essential oil from its leaf exhibited the best repellent activity against mosquitoes. To understand the relationship between volatile organic compounds and repellent activity, the solid-phase microextraction (SPME) method was employed to analyze volatile organic compounds of leaf essential oil. The SPME fiber was coated with divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS). The major volatile organic compounds in the cage were 3-carene, alpha-terpinene, limonene, gamma-terpinene, and terpinolene at 0 min. Results demonstrated that (-)-terpinen-4-ol was the major volatile organic compound adsorbed by SPME fiber during repellent assays. Furthermore, the repellent activities of six compounds against adults of the mosquitoes were evaluated, and the results revealed that (-)-terpinen-4-ol exhibited the best repellent activity against A. aegypti and A. albopictus. PMID:19902948

Gu, Hui-Jing; Cheng, Sen-Sung; Lin, Chun-Ya; Huang, Chin-Gi; Chen, Wei-June; Chang, Shang-Tzen

2009-12-01

251

Calculating the survival rate and estimated population density of gravid Aedes aegypti (Diptera, Culicidae) in Rio de Janeiro, Brazil.  

PubMed

Population size and daily survival rates of disease vectors are important determinants of vectorial capacity. A mark-release-recapture experiment was conducted in a dengue endemic urban neighborhood of Rio de Janeiro, Brazil, to estimate population size, survival rate and vectorial capacity of Aedes aegypti females using back-pack aspirators and gravid sticky traps (MosquiTRAP). Estimations of the gravid female population size were different when using data gathered from just the MosquiTRAP (3,505 individuals) or aspirator (1,470). However Ae. aegypti survival rates and longevity were similar irrespective of the method of capture. Up to 26.3% of released females would be able to survive for more than 10 days, the length of time of the extrinsic incubation period. Vectorial capacity value ranged between 0.01567 and 0.4215 and the basic reproductive number (R0) was estimated to be between 0.0695 and 1.88. PMID:19082265

Maciel-de-Freitas, Rafael; Eiras, Alvaro E; Lourenço-de-Oliveira, Ricardo

2008-12-01

252

Breeding places and seasonal incidence of Aedes aegypti, as assessed by the single-larva survey method*  

PubMed Central

The single-larva survey method was employed to study the breeding places and seasonal incidence of Aedes aegypti in Dar es Salaam, Tanzania. From May 1968 to May 1969, 28 462 containers of water—located in approximately equal numbers indoors and outdoors—were investigated. The highest frequency of breeding (8.0%) of A. aegypti was observed in tires and motor parts. Drums, barrels, water-pots, and other receptacles left outdoors showed a higher frequency (3.1%) than those kept indoors (0.6%). Metal containers were infested to a greater extent than those made of mud, wood, or other materials; 2.5% of coconut shells, snail shells, etc. and 1.3% of tree holes, plant axils, and cut bamboos were infested. The seasonal prevalence, expressed as a container index, closely followed and paralleled the fluctuations in rainfall. The value of this survey method for both ecological studies and practical control purposes is discussed. PMID:4544149

Rao, T. Ramachandra; Trpis, M.; Gillett, J. D.; Teesdale, C.; Tonn, R. J.

1973-01-01

253

Seasonal population dynamics and the genetic structure of the mosquito vector Aedes aegypti in S?o Paulo, Brazil  

PubMed Central

Population genetic studies of insect vectors can generate knowledge to improve epidemiological studies focused on the decrease of pathogen transmission. In this study, we used nine SNPs across the Aedes aegypti genome to characterize seasonal population variations of this important dengue vector. Mosquito samples were obtained by ovitraps placed over Botucatu SP from 2005 to 2010. Our data show that, regardless of the large variation in mosquito abundance (deduced from the number of eggs obtained from ovitraps), the effective population size remained stable over the years. These results suggest that Ae. aegypti is able to maintain a sufficiently large active breeding population during the dry season to keep genetic frequencies stable. These results open new perspectives on mosquito survey and control methods. PMID:23170214

Campos, Melina; Spenassatto, Carine; Lourdes da Graca Macoris, Maria; Paduan, Karina dos Santos; Pinto, Joao; Ribolla, Paulo Eduardo Martins

2012-01-01

254

Chemical composition, oviposition deterrent and larvicidal activities against Aedes aegypti of essential oils from Piper marginatum Jacq. (Piperaceae).  

PubMed

The essential oils of leaves, stems and inflorescences of Piper marginatum, harvested in the Atlantic forest in the State of Pernambuco, Brazil, were obtained by hydrodistillation. GC and GC-MS analyses revealed the presence of 40 components accounting, respectively, for 99.6%, 99.7% and 99.1% of the leaf, stem and inflorescence oil, the most abundant being (Z)- or (E)-asarone and patchouli alcohol. The essential oil of the inflorescences exhibited potent activity against the 4th instar of Aedes aegypti with LC(10) and LC(50) values of 13.8 and 20.0 ppm, respectively. Furthermore, the inflorescence oil did not interfere in the oviposition of A. aegypti females when assayed at 50 ppm. These properties suggest that P. marginatum oil is a potential source of valuable larvicidal compounds for direct use or in conjunction with baits in traps constructed to capture eggs and larvae. PMID:19070480

Autran, E S; Neves, I A; da Silva, C S B; Santos, G K N; da Câmara, C A G; Navarro, D M A F

2009-04-01

255

Discrepancies between Aedes aegypti identification in the field and in the laboratory after collection with a sticky trap  

PubMed Central

Currently, sticky traps are regularly employed to assist in the surveillance of Aedes aegypti infestation. We tested two alternative procedures for specimen identification performed by local health agents: directly in the field, as recommended by certain manufacturers, or after transportation to the laboratory. A total of 384 sticky traps (MosquiTRAP) were monitored monthly during one year in four geographically representative Brazilian municipalities. When the same samples were inspected in the field and in the laboratory, large differences were noted in the total number of mosquitoes recorded and in the number of specimens identified as Ae. aegypti by both procedures. Although field identification has the potential to speed vector surveillance, these results point to uncertainties in the evaluated protocol. PMID:25317711

Maciel-de-Freitas, Rafael; Lima, Arthur Weiss da Silva; Araújo, Simone Costa; Lima, José Bento Pereira; Galardo, Allan Kardec Ribeiro; Honório, Nildimar Alves; Braga, Ima Aparecida; Coelho, Giovanini Evelim; Codeço, Claudia Torres; Valle, Denise

2014-01-01

256

Larvicidal activity against Aedes aegypti of some plants native to the West-Central region of Brazil.  

PubMed

A total of 42 ethanolic extracts from 30 different plant species, native to the Pantanal and Cerrado of the West-Central region of Brazil, have been evaluated for their larvicidal activity against Aedes aegypti larvae, the vector of dengue and dengue hemorrhagic fevers. Among the extracts tested, that obtained from the trunk bark of Ocotea velloziana was the most active. Using a bioassay-directed fractionation of this extract, the active constituent was isolated and characterized as the aporphine alkaloid (+)-dicentrine. Its structure was established on the basis of (1)H and (13)C NMR spectra, optical rotation and by comparison with an authentic sample. This is the first report on the larvicidal activity against A. aegypti of this alkaloid. Our results suggest that (+)-dicentrine may be considered as a promising natural mosquito larvicidal agent. PMID:19664915

Garcez, Walmir S; Garcez, Fernanda R; da Silva, Lilliam M G E; Hamerski, Lidilhone

2009-12-01

257

Phylogeography and Spatio-Temporal Genetic Variation of Aedes aegypti (Diptera: Culicidae) Populations in the Florida Keys  

PubMed Central

Aedes aegypti (L.) is the principal mosquito vector of dengue fever, the second-most deadly vector-borne disease in the world. In Ae. aegypti and other arthropod disease vectors, genetic markers can be used to inform us about processes relevant to disease spread, such as movement of the vectors across space and the temporal stability of vector populations. In late 2009, 27 locally acquired cases of dengue fever were reported in Key West, FL. The last dengue outbreak in the region occurred in 1934. In this study, we used 12 microsatellite loci to examine the genetic structure of 10 Ae. aegypti populations from throughout the Florida Keys and Miami to assess gene flow along the region’s main roadway, the Overseas Highway. We also assessed temporal genetic stability of populations in Key West to determine whether the recent outbreak could have been the result of a new introduction of mosquitoes. Though a small amount of geographic genetic structure was detected, our results showed high overall genetic similarity among Ae. aegypti populations sampled in southeastern Florida. No temporal genetic signal was detected in Key West populations collected before and after the outbreak. Consequently, there is potential for dengue transmission across southeastern Florida; renewed mosquito control and surveillance measures should be taken. PMID:23540116

Brown, Julia E.; Obas, Vanessa; Morley, Valerie; Powell, Jeffrey R.

2013-01-01

258

The impact of larval and adult dietary restriction on lifespan, reproduction and growth in the mosquito Aedes aegypti  

PubMed Central

Dietary restriction extends lifespan in many organisms, but little is known about how it affects hematophagous arthropods. We demonstrated that diet restriction during either larval or adult stages extends Aedes aegypti lifespan. A. aegypti females fed either single or no blood meals survived 30–40% longer than those given weekly blood meals. However, mosquitoes given weekly blood meals produced far more eggs. To minimize reproduction’s impact on lifespan, adult mosquitoes were fed artificial blood meals containing <10% of the protein in normal human blood, minimizing egg production. A. aegypti fed artificial blood meals containing 25 mg/ml of BSA had significantly shorter lifespans than those fed either 10 or 5 mg/ml. To assess the impact of larval dietary restriction on adult lifespan, we maintained larval A. aegypti on 2X, 1X (normal diet), 0.5X or 0.25X diets. Adult mosquitoes fed 0.5X and 0.25X larval diets survived significantly longer than those fed the 2X larval diet regardless of adult diet. In summary, dietary restriction during both larval and adult stages extends lifespan. This diet-mediated lifespan extension has important consequences for understanding how dietary restriction regulates lifespan and disease transmission. PMID:20451597

Joy, Teresa K.; Arik, Anam J.; Corby-Harris, Vanessa; Johnson, Adiv A.; Riehle, Michael A.

2014-01-01

259

Wing Shape as an Indicator of Larval Rearing Conditions for Aedes albopictus and Ae. aegypti (Diptera: Culicidae)  

PubMed Central

Estimating a mosquito’s vector competence, or likelihood of transmitting disease, if it takes an infectious blood meal, is an important aspect of predicting when and where outbreaks of infectious diseases will occur. Vector competence can be affected by rearing temperature and inter- and intraspecific competition experienced by the individual mosquito during its larval development. This research investigates whether a new morphological indicator of larval rearing conditions, wing shape, can be used to distinguish reliably temperature and competitive conditions experienced during larval stages. Aedes albopictus and Aedes aegypti larvae were reared in low intra-specific, high intra-specific, or high inter-specific competition treatments at either 22°C or 32°C. The right wing of each dried female was removed and photographed. Nineteen landmarks and twenty semilandmarks were digitized on each wing. Shape variables were calculated using geometric morphometric software. Canonical variate analysis, randomization multivariate analysis of variance, and visualization of landmark movement using deformation grids provided evidence that although semilandmark position was significantly affected by larval competition and temperature for both species, the differences in position did not translate into differences in wing shape, as shown in deformation grids. Two classification procedures yielded success rates of 26–49%. Accounting for wing size produced no increase in classification success. There appeared to be a significant relationship between shape and size. These results, particularly the low success rate of classification based on wing shape, show that shape is unlikely to be a reliable indicator of larval rearing competition and temperature conditions for Aedes albopictus and Aedes aegypti. PMID:22897054

Stephens, C. R.; Juliano, S. A.

2012-01-01

260

Transcriptomic Profiling of Diverse Aedes aegypti Strains Reveals Increased Basal-level Immune Activation in Dengue Virus-refractory Populations and Identifies Novel Virus-vector Molecular Interactions  

PubMed Central

Genetic variation among Aedes aegypti populations can greatly influence their vector competence for human pathogens such as the dengue virus (DENV). While intra-species transcriptome differences remain relatively unstudied when compared to coding sequence polymorphisms, they also affect numerous aspects of mosquito biology. Comparative molecular profiling of mosquito strain transcriptomes can therefore provide valuable insight into the regulation of vector competence. We established a panel of A. aegypti strains with varying levels of susceptibility to DENV, comprising both laboratory-maintained strains and field-derived colonies collected from geographically distinct dengue-endemic regions spanning South America, the Caribbean, and Southeast Asia. A comparative genome-wide gene expression microarray-based analysis revealed higher basal levels of numerous immunity-related gene transcripts in DENV-refractory mosquito strains than in susceptible strains, and RNA interference assays further showed different degrees of immune pathway contribution to refractoriness in different strains. By correlating transcript abundance patterns with DENV susceptibility across our panel, we also identified new candidate modulators of DENV infection in the mosquito, and we provide functional evidence for two potential DENV host factors and one potential restriction factor. Our comparative transcriptome dataset thus not only provides valuable information about immune gene regulation and usage in natural refractoriness of mosquito populations to dengue virus but also allows us to identify new molecular interactions between the virus and its mosquito vector. PMID:23861987

Sim, Shuzhen; Jupatanakul, Natapong; Ramirez, Jose L.; Kang, Seokyoung; Romero-Vivas, Claudia M.; Mohammed, Hamish; Dimopoulos, George

2013-01-01

261

Impact of a bifenthrin-treated lethal ovitrap on Aedes aegypti oviposition and mortality in north Queensland, Australia.  

PubMed

Lethal ovitraps (LOs) containing an insecticide-treated ovistrip are used as a lure-and-kill device for the container-breeding dengue vector, Aedes aegypti (L.). We aimed to affirm that the pyrethroid bifenthrin could be used effectively in LOs against Ae. aegypti in north Queensland, Australia, by quantifying oviposition in and mortality caused by LOs. Small cage experiments in which individual gravid Ae. aegypti were given a choice of LOs and untreated ovitraps revealed that although LOs were less acceptable for oviposition, they provided an average 64.6% adjusted mortality. Although 92% of mosquitoes ovipositing in LOs died, 61.8% of mosquitoes that visited but did not oviposit in an LO also died, demonstrating that lethal contact occurred without egg laying. The bifenthrin content of strips (approximately 0.1 mg/cm2; 7 mg/strip) did not decrease significantly after 4 wk of field exposure nor did the toxic effect of the LOs. Large cage trials with groups of 10 Ae. aegypti confirmed that bifenthrin-treated LOs provided consistent control (average adjusted mortality 79.7%). Four-week field trials in north Queensland showed that although LOs were acceptable to ovipositing Ae. aegypti (mean time to first egg 10.9 d; mean eggs 47.3), insecticide-free ovitraps were oviposited in more readily (6.8 d, 199 eggs). The number of eggs laid per mosquito in laboratory LOs allowed calculation of the number of Ae. aegypti killed in field-deployed LOs; rapid estimates can be made by simply dividing the number of eggs on the strip by 2.84. Overall, the studies demonstrated that bifenthrin-treated LOs have potential for use as a lure-and-kill device against Ae. aegypti and that they should be effective in the field for at least 4 wk. Given that untreated ovitraps were more acceptable for Ae. aegypti oviposition, the removal of alternative oviposition sites before deployment of LOs in the field should maximize their effectiveness. PMID:17427694

Williams, Craig R; Ritchie, Scott A; Long, Sharron A; Dennison, Nigel; Russell, Richard C

2007-03-01

262

A Secure Semi-Field System for the Study of Aedes aegypti  

PubMed Central

Background New contained semi-field cages are being developed and used to test novel vector control strategies of dengue and malaria vectors. We herein describe a new Quarantine Insectary Level-2 (QIC-2) laboratory and field cages (James Cook University Mosquito Research Facility Semi-Field System; MRF SFS) that are being used to measure the impact of the endosymbiont Wolbachia pipientis on populations of Aedes aegypti in Cairns Australia. Methodology/Principal Findings The MRF consists of a single QIC-2 laboratory/insectary that connects through a central corridor to two identical QIC-2 semi-field cages. The semi-field cages are constructed of two layers of 0.25 mm stainless steel wire mesh to prevent escape of mosquitoes and ingress of other insects. The cages are covered by an aluminum security mesh to prevent penetration of the cages by branches and other missiles in the advent of a tropical cyclone. Parts of the cage are protected from UV light and rainfall by 90% shade cloth and a vinyl cover. A wooden structure simulating the understory of a Queenslander-style house is also situated at one end of each cage. The remainder of the internal aspect of the cage is covered with mulch and potted plants to emulate a typical yard. An air conditioning system comprised of two external ACs that feed cooled, moistened air into the cage units. The air is released from the central ceiling beam from a long cloth tube that disperses the airflow and also prevents mosquitoes from escaping the cage via the AC system. Sensors located inside and outside the cage monitor ambient temperature and relative humidity, with AC controlled to match ambient conditions. Data loggers set in the cages and outside found a <2°C temperature difference. Additional security features include air curtains over exit doors, sticky traps to monitor for escaping mosquitoes between layers of the mesh, a lockable vestibule leading from the connecting corridor to the cage and from inside to outside of the insectary, and screened (0.25 mm mesh) drains within the insectary and the cage. A set of standard operating procedures (SOP) has been developed to ensure that security is maintained and for enhanced surveillance for escaping mosquitoes on the JCU campus where the MRF is located. A cohort of male and female Aedes aegypti mosquitoes were released in the cage and sampled every 3–4 days to determine daily survival within the cage; log linear regression from BG-sentinel trapping collections produced an estimated daily survival of 0.93 and 0.78 for females and males, respectively. Conclusions/Significance The MRF SFS allows us to test novel control strategies within a secure, contained environment. The air-conditioning system maintains conditions within the MRF cages comparable to outside ambient conditions. This cage provides a realistic transitional platform between the laboratory and the field in which to test novel control measures on quarantine level insects. PMID:21445333

Ritchie, Scott A.; Johnson, Petrina H.; Freeman, Anthony J.; Odell, Robin G.; Graham, Neal; DeJong, Paul A.; Standfield, Graeme W.; Sale, Richard W.; O'Neill, Scott L.

2011-01-01

263

Open Field Release of Genetically Engineered Sterile Male Aedes aegypti in Malaysia  

PubMed Central

Background Dengue is the most important mosquito-borne viral disease. In the absence of specific drugs or vaccines, control focuses on suppressing the principal mosquito vector, Aedes aegypti, yet current methods have not proven adequate to control the disease. New methods are therefore urgently needed, for example genetics-based sterile-male-release methods. However, this requires that lab-reared, modified mosquitoes be able to survive and disperse adequately in the field. Methodology/Principal Findings Adult male mosquitoes were released into an uninhabited forested area of Pahang, Malaysia. Their survival and dispersal was assessed by use of a network of traps. Two strains were used, an engineered ‘genetically sterile’ (OX513A) and a wild-type laboratory strain, to give both absolute and relative data about the performance of the modified mosquitoes. The two strains had similar maximum dispersal distances (220 m), but mean distance travelled of the OX513A strain was lower (52 vs. 100 m). Life expectancy was similar (2.0 vs. 2.2 days). Recapture rates were high for both strains, possibly because of the uninhabited nature of the site. Conclusions/Significance After extensive contained studies and regulatory scrutiny, a field release of engineered mosquitoes was safely and successfully conducted in Malaysia. The engineered strain showed similar field longevity to an unmodified counterpart, though in this setting dispersal was reduced relative to the unmodified strain. These data are encouraging for the future testing and implementation of genetic control strategies and will help guide future field use of this and other engineered strains. PMID:22970102

Raduan, Norzahira; Kwee Wee, Lim; Hong Ming, Wong; Guat Ney, Teoh; Rahidah A.A., Siti; Salman, Sawaluddin; Subramaniam, Selvi; Nordin, Oreenaiza; Hanum A.T., Norhaida; Angamuthu, Chandru; Marlina Mansor, Suria; Lees, Rosemary S.; Naish, Neil; Scaife, Sarah; Gray, Pam; Labbe, Genevieve; Beech, Camilla; Nimmo, Derric; Alphey, Luke; Vasan, Seshadri S.; Han Lim, Lee; Wasi A., Nazni; Murad, Shahnaz

2012-01-01

264

Insecticide-driven patterns of genetic variation in the dengue vector Aedes aegypti in Martinique Island.  

PubMed

Effective vector control is currently challenged worldwide by the evolution of resistance to all classes of chemical insecticides in mosquitoes. In Martinique, populations of the dengue vector Aedes aegypti have been intensively treated with temephos and deltamethrin insecticides over the last fifty years, resulting in heterogeneous levels of resistance across the island. Resistance spreading depends on standing genetic variation, selection intensity and gene flow among populations. To determine gene flow intensity, we first investigated neutral patterns of genetic variability in sixteen populations representative of the many environments found in Martinique and experiencing various levels of insecticide pressure, using 6 microsatellites. Allelic richness was lower in populations resistant to deltamethrin, and consanguinity was higher in populations resistant to temephos, consistent with a negative effect of insecticide pressure on neutral genetic diversity. The global genetic differentiation was low, suggesting high gene flow among populations, but significant structure was found, with a pattern of isolation-by-distance at the global scale. Then, we investigated adaptive patterns of divergence in six out of the 16 populations using 319 single nucleotide polymorphisms (SNPs). Five SNP outliers displaying levels of genetic differentiation out of neutral expectations were detected, including the kdr-V1016I mutation in the voltage-gated sodium channel gene. Association tests revealed a total of seven SNPs associated with deltamethrin resistance. Six other SNPs were associated with temephos resistance, including two non-synonymous substitutions in an alkaline phosphatase and in a sulfotransferase respectively. Altogether, both neutral and adaptive patterns of genetic variation in mosquito populations appear to be largely driven by insecticide pressure in Martinique. PMID:24204999

Marcombe, Sébastien; Paris, Margot; Paupy, Christophe; Bringuier, Charline; Yebakima, André; Chandre, Fabrice; David, Jean-Philippe; Corbel, Vincent; Despres, Laurence

2013-01-01

265

Insecticide-Driven Patterns of Genetic Variation in the Dengue Vector Aedes aegypti in Martinique Island  

PubMed Central

Effective vector control is currently challenged worldwide by the evolution of resistance to all classes of chemical insecticides in mosquitoes. In Martinique, populations of the dengue vector Aedes aegypti have been intensively treated with temephos and deltamethrin insecticides over the last fifty years, resulting in heterogeneous levels of resistance across the island. Resistance spreading depends on standing genetic variation, selection intensity and gene flow among populations. To determine gene flow intensity, we first investigated neutral patterns of genetic variability in sixteen populations representative of the many environments found in Martinique and experiencing various levels of insecticide pressure, using 6 microsatellites. Allelic richness was lower in populations resistant to deltamethrin, and consanguinity was higher in populations resistant to temephos, consistent with a negative effect of insecticide pressure on neutral genetic diversity. The global genetic differentiation was low, suggesting high gene flow among populations, but significant structure was found, with a pattern of isolation-by-distance at the global scale. Then, we investigated adaptive patterns of divergence in six out of the 16 populations using 319 single nucleotide polymorphisms (SNPs). Five SNP outliers displaying levels of genetic differentiation out of neutral expectations were detected, including the kdr-V1016I mutation in the voltage-gated sodium channel gene. Association tests revealed a total of seven SNPs associated with deltamethrin resistance. Six other SNPs were associated with temephos resistance, including two non-synonymous substitutions in an alkaline phosphatase and in a sulfotransferase respectively. Altogether, both neutral and adaptive patterns of genetic variation in mosquito populations appear to be largely driven by insecticide pressure in Martinique. PMID:24204999

Paupy, Christophe; Bringuier, Charline; Yebakima, Andre; Chandre, Fabrice; David, Jean-Philippe; Corbel, Vincent; Despres, Laurence

2013-01-01

266

Evolution of insect arylalkylamine N-acetyltransferases: Structural evidence from the yellow fever mosquito, Aedes aegypti  

PubMed Central

Arylalkylamine N-acetyltransferase (aaNAT) catalyzes the transacetylation from acetyl-CoA to arylalkylamines. aaNATs are involved in sclerotization and neurotransmitter inactivation in insects. Phyletic distribution analysis confirms three clusters of aaNAT-like sequences in insects: typical insect aaNAT, polyamine NAT-like aaNAT, and mosquito unique putative aaNAT (paaNAT). Here we studied three proteins: aaNAT2, aaNAT5b, and paaNAT7, each from a different cluster. aaNAT2, a protein from the typical insect aaNAT cluster, uses histamine as a substrate as well as the previously identified arylalkylamines. aaNAT5b, a protein from polyamine NAT -like aaNAT cluster, uses hydrazine and histamine as substrates. The crystal structure of aaNAT2 was determined using single-wavelength anomalous dispersion methods, and that of native aaNAT2, aaNAT5b and paaNAT7 was detected using molecular replacement techniques. All three aaNAT structures have a common fold core of GCN5-related N-acetyltransferase superfamily proteins, along with a unique structural feature: helix/helices between ?3 and ?4 strands. Our data provide a start toward a more comprehensive understanding of the structure–function relationship and physiology of aaNATs from the mosquito Aedes aegypti and serve as a reference for studying the aaNAT family of proteins from other insect species. The structures of three different types of aaNATs may provide targets for designing insecticides for use in mosquito control. PMID:22753468

Han, Qian; Robinson, Howard; Ding, Haizhen; Christensen, Bruce M.; Li, Jianyong

2012-01-01

267

Biochemical analysis of a blood meal-induced Aedes aegypti glutamine synthetase gene.  

PubMed

Glutamine synthetase (GS) in the mosquito, Aedes aegypti, is induced in the midgut following a blood meal. Mosquito GS message is detected as soon as 1 h post-blood feeding and remains stable for 18 h. Using a PCR product encoding mosquito GS, a lambda gt10 adult female mosquito cDNA library was screened. A cDNA clone, pCl5A2, encoding the full translation product of mosquito GS was isolated and sequence analyses performed. Mosquito GS cDNA is 2.5 kb in length and its putative translation product shares all the conserved regions characteristic of the GS gene family, including the presumed ATP biding site. Glutamine synthetase activity in the mosquito midgut is highest at 18 h post-blood feeding. Activity can be detected over a broad pH range, from 6.0 to 7.5. Unlike other cellular GS enzymes, mosquito GS is not active in the presence of ATP. Very low dosages (0.05 mM) of L-methionine S-sulfoximine are sufficient to partially inhibit mosquito GS activity. Inhibition of GS disrupts the normal formation of the midgut peritrophic matrix, suggesting that GS enzyme might be involved in the initial pathway of chitin synthesis. The unique expression pattern and inducible nature of the mosquito GS gene make it an interesting candidate for studying promoter function. Additionally, the blood meal activation of the GS gene makes this a potentially valuable tool in mosquito transformation studies. PMID:9887510

Smartt, C T; Chiles, J; Lowenberger, C; Christensen, B M

1998-12-01

268

Comparative efficacy of two poeciliid fish in indoor cement tanks against chikungunya vector Aedes aegypti in villages in Karnataka, India  

PubMed Central

Background In 2006, severe outbreaks of Aedes aegypti-transmitted chikungunya occurred in villages in Karnataka, South India. We evaluated the effectiveness of combined information, education and communication (IEC) campaigns using two potential poeciliid larvivorous fish guppy (Poecilia reticulata) and mosquitofish (Gambusia affinis), in indoor cement tanks for Aedes larval control. Methods Trials were conducted in two villages (Domatmari and Srinivaspura) in Tumkur District from March to May 2006 for Poecilia and one village (Balmanda) in Kolar District from July to October 2006 for Gambusia. A survey on knowledge, attitude and practice (KAP) on chikungunya was initially conducted and IEC campaigns were performed before and after fish release in Domatmari (IEC alone, followed by IEC + Poecilia) and Balmanda (IEC + Gambusia). In Srinivaspura, IEC was not conducted. Larval surveys were conducted at the baseline followed by one-week and one-month post-intervention periods. The impact of fish on Aedes larvae and disease was assessed based on baseline and post-intervention observations. Results Only 18% of respondents knew of the role of mosquitoes in fever outbreaks, while almost all (n = 50 each) gained new knowledge from the IEC campaigns. In Domatmari, IEC alone was not effective (OR 0.54; p = 0.067). Indoor cement tanks were the most preferred Ae. aegypti breeding habitat (86.9%), and had a significant impact on Aedes breeding (Breteau Index) in all villages in the one-week period (p < 0.001). In the one-month period, the impact was most sustained in Domatmari (OR 1.58, p < 0.001) then Srinivaspura (OR 0.45, p = 0.063) and Balmanda (OR 0.51, p = 0.067). After fish introductions, chikungunya cases were reduced by 99.87% in Domatmari, 65.48% in Srinivaspura and 68.51% in Balmanda. Conclusions Poecilia exhibited greater survival rates than Gambusia (86.04 vs.16.03%) in cement tanks. Neither IEC nor Poecilia alone was effective against Aedes (p > 0.05). We conclude that Poecilia + IEC is an effective intervention strategy. The operational cost was 0.50 (US$ 0.011, 1 US$= 47) per capita per application. Proper water storage practices, focused IEC with Poecilia introductions and vector sanitation involving the local administration and community, is suggested as the best strategy for Aedes control. PMID:21798018

2011-01-01

269

Expression Profile of Genes during Resistance Reversal in a Temephos Selected Strain of the Dengue Vector, Aedes aegypti  

PubMed Central

Background The mosquito Aedes aegypti is one of the most important disease vectors because it transmits two major arboviruses, dengue and yellow fever, which cause significant global morbidity and mortality. Chemical insecticides form the cornerstone of vector control. The organophosphate temephos a larvicide recommended by WHO for controlling Ae. aegypti, however, resistance to this compound has been reported in many countries, including Brazil. Methodology/Principal Findings The aim of this study was to identify genes implicated in metabolic resistance in an Ae. aegypti temephos resistant strain, named RecR, through microarray analysis. We utilized a custom ‘Ae. aegypti detox chip’ and validated microarray data through RT-PCR comparing susceptible and resistant individuals. In addition, we analyzed gene expression in 4th instar larvae from a reversed susceptible strain (RecRev), exposed and unexposed to temephos. The results obtained revealed a set of 13 and 6 genes significantly over expressed in resistant adult mosquitoes and larvae, respectively. One of these genes, the cytochrome P450 CYP6N12, was up-regulated in both stages. RT-PCR confirmed the microarray results and, additionally, showed no difference in gene expression between temephos exposed and unexposed RecRev mosquitoes. This suggested that the differences in the transcript profiles among the strains are heritable due to a selection process and are not caused by immediate insecticide exposure. Reversal of temephos resistance was demonstrated and, importantly, there was a positive correlation between a decrease in the resistance ratio and an accompanying decrease in the expression levels of previously over expressed genes. Some of the genes identified here have also been implicated in metabolic resistance in other mosquito species and insecticide resistant populations of Ae. aegypti. Conclusions/Significance The identification of gene expression signatures associated to insecticide resistance and their suppression could greatly aid the development of improved strategies of vector control. PMID:22870187

Strode, Clare; de Melo-Santos, Maria; Magalhaes, Tereza; Araujo, Ana; Ayres, Contancia

2012-01-01

270

Residual effects of TMOF-Bti formulations against 1st instar Aedes aegypti Linnaeus larvae outside laboratory  

PubMed Central

Objective To evaluate the effectiveness and residual effects of trypsin modulating oostatic factor-Bacillus thuringiensis israeliensis (TMOF-Bti) formulations against Aedes aegypti (Ae. aegypti) (L.) larvae at UKM Campus Kuala Lumpur. Methods Twenty first instar Ae. aegypti larvae were added in each bucket containing 4 L of water supplied with crushed dried leaf powder as their source of food. Combination of TMOF-Bti in rice husk formulation with the following weights viz 10, 25, 50 and 100 mg, respectively in duplicate was distributed in the buckets; while TMOF-Bti in wettable powder formulation each weighing viz 2, 5, 10 and 20 mg, respectively in duplicate was also placed in the buckets. The control buckets run in duplicate with 4 L of water and 20 first instar Ae. aegypti larvae. All buckets were covered with mosquito netting. Larval mortality was recorded after 24 hours and weekly for five weeks. A new batch of 20 1st instar larvae Ae. aegypti was introduced into each bucket weekly without additional TMOF-Bti rice husk formulation or wettable powder. The experiment was repeated for four times. Results The result of the study showed that all formulations were very effective on the first two weeks by giving 100% larval mortality for all concentrations applied. The TMOF (2%) + Bti (2%) had a good residual effect until the end of 3rd week, TMOF (4%) + Bti (4%) until 4th week, wettable powder TMOF (20%) + Bti (20%) until the third week. Conclusions From the results it can be concluded that the TMOF-Bti formulations can be utilized in dengue vector control. PMID:23569922

Saiful, AN; Lau, MS; Sulaiman, S; Hidayatulfathi, O

2012-01-01

271

Disposable containers as larval habitats for Aedes aegypti in a city with regular refuse collection: a study in Marília, São Paulo State, Brazil  

Microsoft Academic Search

In Marília, Brazil, refuse is collected at least every other day, yet non-useful, non-returnable containers such as cans, plastic bottles and tires account for almost half of the container habitats found positive for the Aedes aegypti mosquito. A study was therefore conducted to investigate why these containers exist despite regular refuse collection and a high level of awareness of dengue

C. A. B. Mazine; M. L. G. Macoris; M. T. M. Andrighetti; S. Yasumaro; M. E. Silva; M. J. Nelson; P. J. Winch

1996-01-01

272

Essential oils as potential adulticides against two populations of Aedes aegypti , the laboratory and natural field strains, in Chiang Mai province, northern Thailand  

Microsoft Academic Search

Essential oils derived from five plant species, celery (Apium graveolens), caraway (Carum carvi), zedoary (Curcuma zedoaria), long pepper (Piper longum), and Chinese star anise (Illicium verum), were subjected to investigation of adulticidal activity against mosquito vectors. Two populations of Aedes aegypti, the laboratory and natural field strains, collected in Chiang Mai province, northern Thailand were tested in pyrethroid-susceptibility bioassays. The

Dana Chaiyasit; Wej Choochote; Eumporn Rattanachanpichai; Udom Chaithong; Prasong Chaiwong; Atchariya Jitpakdi; Pongsri Tippawangkosol; Doungrat Riyong; Benjawan Pitasawat

2006-01-01

273

Evaluation on larvicidal effects of essential oils of some local plants against Anopheles arabiensis Patton and Aedes aegypti Linnaeus (Diptera, Culicidae) in Ethiopia  

Microsoft Academic Search

The concern for environmental safety and increased development of resistance to chemical insecticides by major arthropod vectors is rekindling interest in the search for botanical products that may be used against major vectors. Essential oils of 11 local plants were evaluated for larvicidal activities against laboratory colonies of Anopheles arabiensis and Aedes aegypti early fourth instar larvae. Those oils which

Fekadu Massebo; Mekuria Tadesse; Tesfaye Bekele; Meshesha Balkew; Teshome Gebre-Michael

274

Three Novel Families of Miniature Inverted-Repeat Transposable Elements are Associated with Genes of the Yellow Fever Mosquito, Aedes aegypti  

Microsoft Academic Search

Three novel families of transposable elements, Wukong, Wujin, and Wuneng, are described in the yellow fever mosquito, Aedes aegypti. Their copy numbers range from 2,100 to 3,000 per haploid genome. There are high degrees of sequence similarity within each family, and many structural but not sequence similarities between families. The common structural characteristics include small size, no coding potential, terminal

Zhijian Tu

1997-01-01

275

Aedes aegypti, Dengue and Re-urbanization of Yellow Fever in Brazil and other South American Countries - Past and Present Situation and Future Perspectives By  

Microsoft Academic Search

Dengue (DEN) and yellow fever (YF) viruses are two important arboviruses causing human disease. Dengue fever and dengue haemorrhagic fever (DF\\/DHF) reemerged in the Americas after Aedes aegypti had reinfested most tropical and subtropical regions in the hemisphere. The number of DF\\/DHF cases being reported are increasing each year; and in South America only Chile and Uruguay have not reported

Pedro F. C. Vasconcelos; Amélia P. A. T. Rosa; Francisco P. Pinheiro; Sueli G. Rodrigues; Ana C. R. Cruz; Jorge F. S. T. Rosa

276

In-silico homology modeling of three isoforms of insect defensins from the dengue vector mosquito, Aedes aegypti (Linn., 1762).  

PubMed

Dengue is a serious public health problem in tropical and subtropical countries. It is caused by any of the four serologically distinct dengue viruses, namely DENV1-4. The viruses are transmitted by Aedes mosquitoes. Understanding various defence mechanisms of insects has become a prime area of research worldwide. In insects, the first line of defence against invading pathogens includes cellular mechanisms and a battery of antimicrobial peptides such as defensins, cecropins etc. Defensins--cationic, cysteine-rich peptides consisting of approximately 40 amino acids with broad-spectrum activity against Gram-positive bacteria--have been reported from a wide range of organisms. In the dengue vector mosquito, Aedes aegypti, three isoforms of defensins are reported to be expressed in a spatial and temporal fashion. This report presents the three-dimensional structures of the three isoforms of Ae. aegypti defensins predicted by comparative modeling. Prediction was done with Modeller 9v1 and the structures validated through a series of tests. The best results of the prediction study are presented, and may help lead to the discovery of new synthetic peptides or derivatives of defensins that could be useful in the control of vector-borne diseases. PMID:19085024

Dhananjeyan, K J; Sivaperumal, R; Paramasivan, R; Thenmozhi, V; Tyagi, B K

2009-05-01

277

Co-occurrence of Point Mutations in the Voltage-Gated Sodium Channel of Pyrethroid-Resistant Aedes aegypti Populations in Myanmar  

PubMed Central

Background Single amino acid substitutions in the voltage-gated sodium channel associated with pyrethroid resistance constitute one of the main causative factors of knockdown resistance in insects. The kdr gene has been observed in several mosquito species; however, point mutations in the para gene of Aedes aegypti populations in Myanmar have not been fully characterized. The aim of the present study was to determine the types and frequencies of mutations in the para gene of Aedes aegypti collected from used tires in Yangon City, Myanmar. Methodology/Principal Findings We determined high pyrethroid resistance in Aedes aegypti larvae at all collection sites in Yangon City, by using a simplified knockdown bioassay. We showed that V1016G and S989P mutations were widely distributed, with high frequencies (84.4% and 78.8%, respectively). By contrast, we were unable to detect I1011M (or I1011V) or L1014F mutations. F1534C mutations were also widely distributed, but with a lower frequency than the V1016G mutation (21.2%). High percentage of co-occurrence of the homozygous V1016G/S989P mutations was detected (65.7%). Additionally, co-occurrence of homozygous V1016G/F1534C mutations (2.9%) and homozygous V1016G/F1534C/S989P mutations (0.98%) were detected in the present study. Conclusions/Significance Pyrethroid insecticides were first used for malaria control in 1992, and have since been constantly used in Myanmar. This intensive use may explain the strong selection pressure toward Aedes aegypti, because this mosquito is generally a domestic and endophagic species with a preference for indoor breeding. Extensive use of DDT for malaria control before the use of this chemical was banned may also explain the development of pyrethroid resistance in Aedes aegypti. PMID:25077956

Kawada, Hitoshi; Oo, Sai Zaw Min; Thaung, Sein; Kawashima, Emiko; Maung, Yan Naung Maung; Thu, Hlaing Myat; Thant, Kyaw Zin; Minakawa, Noboru

2014-01-01

278

Collagen-binding protein, Aegyptin, regulates probing time and blood feeding success in the dengue vector mosquito, Aedes aegypti  

PubMed Central

Mosquito salivary glands have important roles in blood feeding and pathogen transmission. However, the biological relevance of many salivary components has yet to be determined. Aegyptin, a secreted salivary protein from Aedes aegypti, binds collagen and inhibits platelet aggregation and adhesion. We used a transgenic approach to study the relevance of Aegyptin in mosquito blood feeding. Aedes aegypti manipulated genetically to express gene-specific inverted-repeat RNA sequences exhibited significant reductions in Aegyptin mRNA accumulation (85–87%) and protein levels (>80-fold) in female mosquito salivary glands. Transgenic mosquitoes had longer probing times (78–300 s, P < 0.0001) when feeding on mice compared with controls (15–56 s), feeding success was reduced, and those feeding took smaller blood meals. However, no differences in feeding success or blood meal size were found in membrane feeding experiments using defibrinated human blood. Salivary gland extracts from transgenic mosquitoes failed to inhibit collagen-induced platelet aggregation in vitro. Reductions of Aegyptin did not affect salivary ADP-induced platelet aggregation inhibition or disturb anticlotting activities. Our results demonstrate the relevance of Aegyptin for A. aegypti blood feeding, providing further support for the hypothesis that platelet aggregation inhibition is a vital salivary function in blood feeding arthropods. It has been suggested that the multiple mosquito salivary components mediating platelet aggregation (i.e., Aegyptin, apyrase, D7) represent functional redundancy. Our findings do not support this hypothesis; instead, they indicate that multiple salivary components work synergistically and are necessary to achieve maximum blood feeding efficiency. PMID:24778255

Chagas, Andrezza Campos; Ramirez, Jose Luis; Jasinskiene, Nijole; James, Anthony A.; Ribeiro, Jose M. C.; Marinotti, Osvaldo; Calvo, Eric

2014-01-01

279

Survival of larvivorous fish used for biological control of Aedes aegypti larvae in domestic containers with different chlorine concentrations.  

PubMed

The two fish species Betta splendens (Regan) and Poecilia reticulata (Peters) are known predators of Aedes aegypti (L., 1762) larvae. Both species have been used for biological control in northeastern Brazil. However, the feasibility of these fish for the control of Ae. aegypti larvae in domestic containers may be limited by their survival in chlorinated water, as supplied by the public water system. We exposed fish to three different concentrations of chlorine: 1, 1.5, and 2.0 mg/liter. All B. splendens survived at 1.0 mg/liter chlorine concentration; 72.5 and 39.3% of B. splendens survived chlorine concentrations of 1.5 and 2.0 mg/liter, respectively. In contrast, only 4.4% of P. reticulata survived at a chlorine concentration of 1.0 mg/liter. We conclude that B. splendens may be an appropriate species for biological control of Ae. aegypti in domestic water tanks. PMID:19645286

Cavalcanti, Luciano Pamplona de Góes; de Paula, Francisco José Júnior; Pontes, Ricardo José Soares; Heukelbach, Jorg; Lima, José Wellington de Oliveira

2009-07-01

280

Susceptibility of Aedes aegypti, Culex quinquefasciatus Say, and Anopheles quadrimaculatus Say to 19 pesticides with different modes of action.  

PubMed

To access the relative potency of pesticides to control adult mosquitoes, 19 pesticides with various modes of action were evaluated against Aedes aegypti, Culex quinquefasciatus Say, and Anopheles quadrimaculatus Say. On the basis of 24-h LD50 values after topical application, the only pesticide that had higher activity than permethrin was fipronil, with LD50 values lower than permethrin for 107-, 4,849-, and 2-fold against Ae. aegypti, Cx. quinquefasciatus Say, and An. quadrimaculatus Say, respectively. Abamectin, imidacloprid, spinosad, diazinon, and carbaryl showed slightly lower activity than permethrin (<20-fold). However, bifenazate showed very low activity against the three mosquito species tested, with LD50 values higher than permthrin for >1000-fold. On the basis of 24-h LD50 values, Cx. quinquefasciatus was the least susceptible species to nine pesticides tested (DNOC, azocyclotin, chlorfenapyr, carbaryl, spinosad, imidaclorid, diazinon, abamectin, and permethrin) , whereas Ae. aegypti was the least susceptible species to six pesticides tested (dicofol, amitraz, propargite, hydramethylnon, cyhexatin, and diafenthiuron), and An. quadrimaculatus was the least susceptible species to four pesticides tested (bifenazate, pyridaben, indoxacarb, and fipronil). Our results revealed that different species of mosquitoes had different susceptibility to pesticides, showing the need to select the most efficacious compounds for the least susceptible mosquito species to achieve successful mosquito control. PMID:18283946

Pridgeon, Julia W; Pereira, Roberto M; Becnel, James J; Allan, Sandra A; Clark, Gary G; Linthicum, Kenneth J

2008-01-01

281

Vector control measures failed to affect genetic structure of Aedes aegypti in a sentinel metropolitan area of Brazil.  

PubMed

In order to evaluate subpopulation differentiation, effective population size (Ne) and evidence for population bottlenecks at various geographic levels, Aedes aegypti larvae were collected longitudinally from 2007 to 2009 from four areas in the city of Salvador, Brazil. The DNA from each larva was isolated and genotyped with five independent microsatellite markers. FST and Jost's D revealed significant population structuring (P<0.05) at the municipal and regional levels, while only RST was able to detect genetic differentiation at the level of strata within these areas. Ne analysis from longitudinal data did not show any evidence of significant change in population structure. The census population measured by the house index, however, showed a significant trend toward decrease in these areas. Active vector control measures did contribute to vector reduction, but this was not enough to decrease A. aegypti population genetic diversity in Salvador. The understanding of A. aegypti population dynamics may be helpful for planning and evaluation of control measures to make them more effective. PMID:24028791

Souza, Kathleen R; Ribeiro, Gilmar; Silva dos Santos, Carlos Gustavo; de Lima, Eliaci Couto; Melo, Paulo R S; Reis, Mitermayer G; Blanton, Ronald E; Silva, Luciano K

2013-12-01

282

microRNA miR-275 is indispensable for blood digestion and egg development in the mosquito Aedes aegypti  

PubMed Central

The mosquito Aedes aegypti is the major vector of arboviral diseases, particularly of Dengue fever, of which there are more than 100 million cases annually. Mosquitoes, such as A. aegypti, serve as vectors for disease pathogens because they require vertebrate blood for their egg production. Pathogen transmission is tightly linked to repeated cycles of obligatory blood feeding and egg maturation. Thus, the understanding of mechanisms governing egg production is necessary to develop approaches that limit the spread of mosquito-borne diseases. Previous studies have identified critical roles of hormonal- and nutrition-based target of rapamycin (TOR) pathways in controlling blood-meal–mediated egg maturation in mosquitoes. In this work, we uncovered another essential regulator of blood-meal–activated processes, the microRNA miR-275. The depletion of this microRNA in A. aegypti females after injection of its specific antagomir resulted in severe defects in blood digestion, fluid excretion, and egg development, clearly demonstrating that miR-275 is indispensable for these physiological processes. miR-275 exhibits an expression profile that suggests its regulation by a steroid hormone, 20-hydroxyecdysone (20E). In vitro organ culture experiments demonstrated that miR-275 is induced by this hormone in the presence of amino acids, indicative of a dual regulation by 20E and TOR. This report has uncovered the critical importance of microRNAs in controlling blood-meal–activated physiological events required for completion of egg development in mosquito disease vectors. PMID:21115818

Bryant, Bart; Macdonald, Warren; Raikhel, Alexander S.

2010-01-01

283

Overlapping genes of Aedes aegypti: evolutionary implications from comparison with orthologs of Anopheles gambiae and other insects  

PubMed Central

Background Although gene overlapping is a common feature of prokaryote and mitochondria genomes, such genes have also been identified in many eukaryotes. The overlapping genes in eukaryotes are extensively rearranged even between closely related species. In this study, we investigated retention and rearrangement of positionally overlapping genes between the mosquitoes Aedes aegypti (dengue virus vector) and Anopheles gambiae (malaria vector). The overlapping gene pairs of A. aegypti were further compared with orthologs of other selected insects to conduct several hypothesis driven investigations relating to the evolution and rearrangement of overlapping genes. Results The results show that as much as ~10% of the predicted genes of A. aegypti and A. gambiae are localized in positional overlapping manner. Furthermore, the study shows that differential abundance of introns and simple sequence repeats have significant association with positional rearrangement of overlapping genes between the two species. Gene expression analysis further suggests that antisense transcripts generated from the oppositely oriented overlapping genes are differentially regulated and may have important regulatory functions in these mosquitoes. Our data further shows that synonymous and non-synonymous mutations have differential but non-significant effect on overlapping localization of orthologous genes in other insect genomes. Conclusion Gene overlapping in insects may be a species-specific evolutionary process as evident from non-dependency of gene overlapping with species phylogeny. Based on the results, our study suggests that overlapping genes may have played an important role in genome evolution of insects. PMID:23777277

2013-01-01

284

The efficacy of a chitin synthesis inhibitor against field populations of organophosphate-resistant Aedes aegypti in Brazil.  

PubMed

The mosquito Aedes aegypti is the main focus of dengue control campaigns. Because of widespread resistance against conventional chemical insecticides, chitin synthesis inhibitors (CSIs) are considered control alternatives. We evaluated the resistance status of four Brazilian Ae. aegypti populations to both the organophosphate temephos and the pyrethroid deltamethrin, which are used in Brazil to control larvae and adults, respectively. All vector populations exhibited high levels of temephos resistance and varying rates of alterations in their susceptibility to pyrethroids. The effect of the CSI novaluron on these populations was also investigated. Novaluron was effective against all populations under laboratory conditions. Field-simulated assays with partial water replacement were conducted to evaluate novaluron persistence. Bioassays were continued until an adult emergence inhibition of at least 70% was attained. We found a residual effect of eight weeks under indoor conditions and novaluron persisted for five-six weeks in assays conducted in an external area. Our data show that novaluron is effective against the Ae. aegypti populations tested, regardless of their resistance to conventional chemical insecticides. PMID:22510835

Fontoura, Nathalia Giglio; Bellinato, Diogo Fernandes; Valle, Denise; Lima, José Bento Pereira

2012-05-01

285

A Critical Role of the Nuclear Receptor HR3 in Regulation of Gonadotrophic Cycles of the Mosquito Aedes aegypti  

PubMed Central

The orphan nuclear receptor HR3 is essential for developmental switches during insect development and metamorphosis regulated by 20-hydroxyecdysone (20E). Reproduction of female mosquitoes of the major vector of Dengue fever, Aedes aegypti, is cyclic because of its dependence on blood feeding. 20E is an important hormone regulating vitellogenic events in this mosquito; however, any role for HR3 in 20E-driven reproductive events has not been known. Using RNA interference (RNAi) approach, we demonstrated that Aedes HR3 plays a critical role in a timely termination of expression of the vitellogenin (Vg) gene encoding the major yolk protein precursor. It is also important for downregulation of the Target-of-Rapamycin pathway and activation of programmed autophagy in the Aedes fat body at the end of vitellogenesis. HR3 is critical in activating betaFTZ-F1, EcRB and USPA, the expressions of which are highly elevated at the end of vitellogenesis. RNAi depletion of HR3 (iHR3) prior to the first gonadotrophic cycle affects a normal progression of the second gonadotrophic cycle. Most of ovaries 24 h post second blood meal from iHR3 females in the second cycle were small with follicles that were only slightly different in length from of those of resting stage. In addition, these iHR3 females laid a significantly reduced number of eggs per mosquito as compared to those of iMal and the wild type. Our results indicate an important role of HR3 in regulation of 20E-regulated developmental switches during reproductive cycles of A. aegypti females. PMID:23049766

Mane-Padros, Daniel; Cruz, Josefa; Cheng, Andrew; Raikhel, Alexander S.

2012-01-01

286

Biochemical, Molecular, and Functional Characterization of PISCF-Allatostatin, a Regulator of Juvenile Hormone Biosynthesis in the Mosquito Aedes aegypti*S  

PubMed Central

Aedes aegypti PISCF-allatostatin or allatostatin-C (Ae-AS-C) was isolated using a combination of high performance liquid chromatography and enzyme-linked immunosorbent assay (ELISA). The matrix-assisted laser desorption/ionization time-of-flight (TOF) mass spectrum of positive ELISA fractions revealed a molecular mass of 1919.0 Da, in agreement with the sequence qIRYRQCYFNPISCF, with bridged cysteines. This sequence was confirmed by matrix-assisted laser desorption/ionization tandem TOF/TOF mass spectrometry analysis. The corresponding Ae-AS-C cDNA was amplified by PCR, and the sequence of the peptide was confirmed. An in vitro radiochemical assay was used to study the inhibitory effect of synthetic Ae-AS-C on juvenile hormone biosynthesis by the isolated corpora allata (CA) of adult female A. aegypti. The inhibitory action of synthetic Ae-AS-C was dose-dependent; with a maximum at 10?9 M. Ae-AS-C showed no inhibitory activity in the presence of farnesoic acid, an immediate precursor of juvenile hormone, indicating that the Ae-AS-C target is located before the formation of farnesoic acid in the pathway. The sensitivity of the CA to inhibition by Ae-AS-C in the in vitro assay varied during the adult life; the CA was most sensitive during periods of low synthetic activity. In addition, the levels of Ae-AS-C in the brain were studied using ELISA and reached a maximum at 3 days after eclosion. These studies suggest that Ae-AS-C is an important regulator of CA activity in A. aegypti. PMID:16968697

Li, Yiping; Hernandez-Martinez, Salvador; Fernandez, Facundo; Mayoral, Jaime G.; Topalis, Pantelis; Priestap, Horacio; Perez, Mario; Navare, Arti; Noriega, Fernando G.

2009-01-01

287

Temporal Patterns of Abundance of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) and Mitochondrial DNA Analysis of Ae. albopictus in the Central African Republic  

PubMed Central

The invasive Asian tiger mosquito Aedes albopictus (Diptera: Culicidae) was first reported in central Africa in 2000, in Cameroon, with the indigenous mosquito species Ae. aegypti (Diptera: Culicidae). Today, this invasive species is present in almost all countries of the region, including the Central African Republic (CAR), where it was first recorded in 2009. As invasive species of mosquitoes can affect the distribution of native species, resulting in new patterns of vectors and concomitant risk for disease, we undertook a comparative study early and late in the wet season in the capital and the main cities of CAR to document infestation and the ecological preferences of the two species. In addition, we determined the probable geographical origin of invasive populations of Ae. albopictus with two mitochondrial DNA genes, COI and ND5. Analysis revealed that Ae. aegypti was more abundant earlier in the wet season and Ae. albopictus in the late wet season. Used tyres were the most heavily colonized productive larval habitats for both species in both seasons. The invasive species Ae. albopictus predominated over the resident species at all sites in which the two species were sympatric. Mitochondrial DNA analysis revealed broad low genetic diversity, confirming recent introduction of Ae. albopictus in CAR. Phylogeographical analysis based on COI polymorphism indicated that the Ae. albopictus haplotype in the CAR population segregated into two lineages, suggesting multiple sources of Ae. albopictus. These data may have important implications for vector control strategies in central Africa. PMID:24349596

Kamgang, Basile; Ngoagouni, Carine; Manirakiza, Alexandre; Nakoune, Emmanuel; Paupy, Christophe; Kazanji, Mirdad

2013-01-01

288

Aedes aegypti (Diptera: Culicidae) biting deterrence: structure-activity relationship of saturated and unsaturated fatty acids.  

PubMed

In this study we evaluated the biting deterrent effects of a series of saturated and unsaturated fatty acids against Aedes aegypti (L), yellow fever mosquito (Diptera: Culicidae) using the K & Dbioassay module system. Saturated (C6:0 to C16:0 and C18:0) and unsaturated fatty acids (C11:1 to C14:1, C16:1, C18:1, and C18:2) showed biting deterrence index (BDI) values significantly greater than ethanol, the negative control. Among the saturated fatty acids, mid chain length acids (C10:0 to C13:0) showed higher biting deterrence than short (C6:0 to C9:0) and long chain length acids (C14:0 to C18:0), except for C8:0 and C16:0 that were more active than the other short and long chain acids. The BDI values of mid chain length acids (C10:0 to C13:0) were not significantly less than N, N-diethyl-meta-toluamide (DEET), the positive control. Among the unsaturated fatty acids, C11:1 showed the highest activity (BDI = 1.05) and C18:2 had the lowest activity (BDI = 0.7). In C11:1, C12:1, and C14:1 BDI values were not significantly less than DEET. After the preliminary observations, residual activity bioassays were performed on C11:0, C12:0, C11:1, and C12:1 over a 24-h period. All the fatty acids (C11:0, C12:0, C11:1, and C12:1) and DEET showed significantly higher activity at all test intervals than the solvent control. At treatment and 1-h posttreatment, all fatty acids showed proportion not biting (PNB) values not significantly less than DEET. At 3-, 6-, and 12-h posttreatment, all fatty acids showed PNB values significantly greater than DEET. At 24-h posttreatment, only the PNB value for C12:0 was significantly higher than DEET. The dose-responses of C12:0 and DEET were determined at concentrations of 5-25 nmol/cm2. As in the residual activity bioassays, the PNB values for C12:0 and DEET at 25 nmol/cm(2) were not significantly different. However, at lower concentrations, the PNB values for C12:0 were significantly greater than DEET. These results clearly indicate that mid chain length fatty acids not only have levels of biting deterrence similar to DEET at 25 nmnol/cm(2) in our test system, but also appeared to be more persistent than DEET. In contrast, in vivo cloth patch assay system showed that the mid-chain length fatty acids, C11:0, C11:1, C12:0, and C12:1 had minimum effective dose (MED) values greater than DEET against Ae. aegypti and their relative repellency varied according to species tested. The MED values of 120 (C11:0), 145 (C12:0) and 116 (C11:1) nmol/cm(2) against Anopheles quadrimaculatus Say, indicated that these acids were not as potent as DEET with a MED of 54 nmol/cm(2). The MED ratio of the C11:0 and C11:1 for all three mosquito species indicated the C11 saturated and unsaturated acids as more repellent than their corresponding C12:0 and C12:1 homologues. PMID:23270165

Ali, Abbas; Cantrell, Charles L; Bernier, Ulrich R; Duke, Stephen O; Schneider, John C; Agramonte, Natasha M; Khan, Ikhlas

2012-11-01

289

First report on susceptibility of wild Aedes aegypti (Diptera: Culicidae) using Carapa guianensis (Meliaceae) and Copaifera sp. (Leguminosae).  

PubMed

Oils of Carapa guianensis and Copaifera spp. are well known in the Amazonian region as natural insect repellent, and studies have reported their efficiency as larvicide against some laboratory mosquito species. However, in wild populations of mosquitoes, these oils have not yet been evaluated. Thus, the objective of this study was to investigate their efficiency as larvicide in wild populations of Aedes aegypti with a history of exposure to organophosphate. The susceptibility of larvae was determined under three different temperatures, 15°C, 20°C, and 30°C. For each test, 1,000 larvae were used (late third instar and early fourth instar-four replicates of 25 larvae per concentration). Statistical tests were used to identify significant differences. The results demonstrated that as the laboratory A. aegypti, the wild populations of A. aegypti were also susceptible to C. guianensis and Copaifera sp. oils. The lethal concentrations for Copaifera sp. ranged from LC(50) 47 to LC(90) 91 (milligrams per liter), and for C. guianensis, they were LC(50) 136 to LC(90) 551 (milligrams per liter). In relation to different temperature, the effectiveness of the oils on larvae mortality was directly related to the increase of temperature, and better results were observed for temperature at 25°C. The results presented here indicate the potential larvicidal activity of C. guianensis and species of Copaifera, in populations of A. aegypti from the wild. Therefore, the results presented here are very important since such populations are primarily responsible for transmitting the dengue virus in the environment. PMID:21779861

Prophiro, Josiane S; da Silva, Mario Antonio Navarro; Kanis, Luiz A; da Rocha, Louyse Caroline B P; Duque-Luna, Jonny E; da Silva, Onilda S

2012-02-01

290

A GPI-anchored alkaline phosphatase is a functional midgut receptor of Cry11Aa toxin in Aedes aegypti larvae.  

PubMed

A 65 kDa GPI (glycosylphosphatidyl-inositol)-anchored ALP (alkaline phosphatase) was characterized as a functional receptor of the Bacillus thuringiensis subsp. israelensis Cry11Aa toxin in Aedes aegypti midgut cells. Two (a 100 kDa and a 65 kDa) GPI-anchored proteins that bound Cry11Aa toxin were preferentially extracted after treatment of BBMV (brush boder membrane vesicles) from Ae. aegypti midgut epithelia with phospholipase C. The 65 kDa protein was further purified by toxin affinity chromatography. The 65 kDa protein showed ALP activity. The peptide-displaying phages (P1.BBMV and P8.BBMV) that bound to the 65 kDa GPI-ALP (GPI-anchored ALP) and competed with the Cry11Aa toxin to bind to BBMV were isolated by selecting BBMV-binding peptide-phages by biopanning. GPI-ALP was shown to be preferentially distributed in Ae. aegypti in the posterior part of the midgut and in the caeca, by using P1.BBMV binding to fixed midgut tissue sections to determine the location of GPI-ALP. Cry11Aa binds to the same regions of the midgut and competed with P1.BBMV and P8.BBMV to bind to BBMV. The importance of this interaction was demonstrated by the in vivo attenuation of Cry11Aa toxicity in the presence of these phages. Our results shows that GPI-ALP is an important receptor molecule involved in Cry11Aa interaction with midgut cells and toxicity to Ae. aegypti larvae. PMID:16255715

Fernandez, Luisa E; Aimanova, Karlygash G; Gill, Sarjeet S; Bravo, Alejandra; Soberón, Mario

2006-02-15

291

Insecticidal and genotoxic potential of two semi-synthetic derivatives of dillapiole for the control of Aedes (Stegomyia) aegypti (Diptera: Culicidae).  

PubMed

The effects of two semi-synthetic dillapiole derivatives, ethyl-ether dillapiole and n-butyl ether dillapiole, on eggs and larvae of Aedes aegypti were studied in view of the need for expansion and renovation of strategic action to control this mosquito - the vector of Dengue virus -, which currently shows a high resistance to chemical insecticides. Eggs and third-instar larvae of A. aegypti that had been exposed to different concentrations of these two compounds showed toxicity and susceptibility, with 100% mortality. Classical cytogenetic assays showed genotoxicity caused by the two compounds in A. aegypti from the cumulative effect of nuclear abnormalities, indicating that these derivatives may be potential alternatives to control A. aegypti. PMID:25308546

Domingos, Pedro Rauel Cândido; da Silva Pinto, Ana Cristina; Dos Santos, Joselita Maria Mendes; Rafael, Míriam Silva

2014-09-15

292

Effects of marking methods and fluorescent dusts on Aedes aegypti survival  

PubMed Central

Background Tracking the movement of mosquitoes and understanding dispersal dynamics is essential for the control and prevention of vector-borne diseases. A variety of marking techniques have been used, including dusts and dyes. Methods In this study, Aedes aegypti were marked using fluorescent dusts (‘DayGlo’: A-19 Horizon Blue & A-13-N Rocket Red; ‘Brian Clegg’: pink, blue & red), fluorescent paints (‘Brian Clegg’: blue, red & yellow) and metallic gold dust (‘Brian Clegg’). Dusting methods were those previously used in mark-release-recapture experiments, including application with a bulb duster, creation of a dust storm or shaking in a bag. Results Results showed marking mosquitoes using a dust storm allowed relatively high survival, compared to unmarked controls (Males: ?2?=?3.24, df?=?4, p?=?0.07; Females: ?2?=?3.24, df?=?4, p?=?0.04), and high marking efficiency. Using a bulb duster showed high survival in male mosquitoes (?2?=?12.59, df?=?4, p?

2014-01-01

293

Wide spread cross resistance to pyrethroids in Aedes aegypti (Diptera: Culicidae) from Veracruz state Mexico.  

PubMed

Seven F1 strains of Aedes aegypti (L.) were evaluated by bottle bioassay for resistance to the pyrethroids d-phenothrin, permethrin, deltamethrin, lambda-cyalothrin, bifenthrin, cypermethrin, alpha-cypermethrin, and z-cypermethrin. The New Orleans strain was used as a susceptible control. Mortality rates after a 1 h exposure and after a 24 h recovery period were determined. The resistance ratio between the 50% knockdown values (RR(KC50)) of the F1 and New Orleans strains indicated high levels of knockdown resistance. The RR(KC50) with alpha-cypermethrin varied from 10 to 100 among strains indicating high levels of knockdown resistance. Most of the strains had moderate resistance to d-phenothrin. Significant but much lower levels of resistance were detected for lambda-cyalothrin, permethrin, and cypermethrin. For zeta-cypermethrin and bifenthrin, only one strain exhibited resistance with RR(KC50) values of 10- and 21-fold, respectively. None of the strains showed RR(KC50) >10 with deltamethrin, and moderate resistance was seen in three strains, while the rest were susceptible. Mosquitoes from all strains exhibited some recovery from all pyrethroids except d-phenothrin. Regression analysis was used to analyze the relationship between RR(LC50) and RR(KC50). Both were highly correlated (R2 = 0.84-0.97) so that the slope could be used to determine how much additional pyrethroid was needed to ensure lethality. Slopes ranged from 0.875 for d-phenothrin (RR(LC50) approximately equal to RR(KC50)) to 8.67 for lambda-cyalothrin (-8.5-fold more insecticide needed to kill). Both RR(LC50) and RR(KC50) values were highly correlated for all pyrethroids except bifenthrin indicating strong cross-resistance. Bifenthrin appears to be an alternative pyrethroid without strong cross-resistance that could be used as an alternative to the current widespread use of permethrin in Mexico. PMID:23786088

Flores, Adriana E; Ponce, Gustavo; Silva, Brenda G; Gutierrez, Selene M; Bobadilla, Cristina; Lopez, Beatriz; Mercado, Roberto; Black, William C

2013-04-01

294

Mosquito larvicidal, ovicidal, and repellent properties of botanical extracts against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae).  

PubMed

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. In mosquito control programs, botanical origin may have the potential to be used successfully as eggs, larvae, and adult. The larvicidal, ovicidal, and repellent activities of crude benzene and ethyl acetate extracts of leaf of Ervatamia coronaria and Caesalpinia pulcherrima were assayed for their toxicity against three important vector mosquitoes, viz., Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae). The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in benzene extract of E. coronaria against the larvae of Anopheles Stephensi, Aedes aegypti, and Culex quinquefasciatus with the LC(50) and LC(90) values were 79.08, 89.59, and 96.15 ppm and 150.47, 166.04, and 174.10 ppm, respectively. Mean percent hatchability of the ovicidal activity was observed 48 h posttreatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. The leaf extract of E. coronaria was found to be most effective than Caesalpinia pulcherrima against eggs/egg rafts of three vector mosquitoes. For E. coronaria, the benzene extract exerted 300, 250, and 200 ppm against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus, respectively. The results of the repellent activity of benzene and ethyl acetate extract of E. coronaria and Caesalpinia pulcherrima plants at three different concentrations of 1.0, 2.5, and 5.0 mg/cm(2) were applied on skin of fore arm in man and exposed against adult female mosquitoes. In this observation, these two plant crude extracts gave protection against mosquito bites without any allergic reaction to the test person, and also, the repellent activity is dependent on the strength of the plant extracts. These results suggest that the leaf solvent plant extracts have the potential to be used as an ideal ecofriendly approach for the control of mosquitoes. This is the first report on the mosquito larvicidal, ovicidal, and repellent activities of the reported E. coronaria and Caesalpinia pulcherrima plants. PMID:21318385

Govindarajan, M; Mathivanan, T; Elumalai, K; Krishnappa, K; Anandan, A

2011-08-01

295

Cloning and functional characterization of inward-rectifying potassium (Kir) channels from Malpighian tubules of the mosquito Aedes aegypti  

PubMed Central

Inward-rectifying K+ (Kir) channels play critical physiological roles in a variety of vertebrate cells/tissues, including the regulation of membrane potential in nerve and muscle, and the transepithelial transport of ions in osmoregulatory epithelia, such as kidneys and gills. It remains to be determined whether Kir channels play similar physiological roles in insects. In the present study, we sought to 1) clone the cDNAs of Kir channel subunits expressed in the renal (Malpighian) tubules of the mosquito Aedes aegypti, and 2) characterize the electrophysiological properties of the cloned Kir subunits when expressed heterologously in oocytes of Xenopus laevis. Here, we reveal that three Kir subunits are expressed abundantly in Aedes Malpighian tubules (AeKir1, AeKir2B, and AeKir3); each of their full-length cDNAs was cloned. Heterologous expression of the AeKir1 or the AeKir2B subunits in Xenopus oocytes elicits inward-rectifying K+ currents that are blocked by barium. Relative to the AeKir2B-expressing oocytes, the AeKir1-expressing oocytes 1) produce larger macroscopic currents, and 2) exhibit a modulation of their conductive properties by extracellular Na+. Attempts to functionally characterize the AeKir3 subunit in Xenopus oocytes were unsuccessful. Lastly, we show that in isolated Aedes Malpighian tubules, the cation permeability sequence of the basolateral membrane of principal cells (Tl+ > K+ > Rb+ > NH4+) is consistent with the presence of functional Kir channels. We conclude that in Aedes Malpighian tubules, Kir channels contribute to the majority of the barium-sensitive transepithelial transport of K+. PMID:23085358

Piermarini, Peter M.; Rouhier, Matthew F.; Schepel, Matthew; Kosse, Christin; Beyenbach, Klaus W.

2013-01-01

296

Aedes aegypti cadherin serves as a putative receptor of the Cry11Aa toxin from Bacillus thuringiensis subsp. israelensis.  

PubMed

Cry11Aa of Bacillus thuringiensis subsp. israelensis is the most active toxin to Aedes aegypti in this strain. We previously reported that, in addition to a 65 kDa GPI (glycosylphosphatidylinositol)-anchored ALP (alkaline phosphatase), the toxin also binds a 250 kDa membrane protein. Since this protein is the same size as cadherin, which in lepidopteran insects is an important Cry toxin receptor, we developed an anti-AaeCad antibody. This antibody detects a 250 kDa protein in immunoblots of larval BBMVs (brush border membrane vesicles). The antibody inhibits Cry11Aa toxin binding to BBMVs and immunolocalizes the cadherin protein to apical membranes of distal and proximal caecae and posterior midgut epithelial cells. This localization is consistent with areas to which Cry11Aa toxin binds and causes pathogenicity. Therefore, the full-length Aedes cadherin cDNA was isolated from Aedes larvae and partial overlapping fragments that covered the entire protein were expressed in Escherichia coli. Using toxin overlay assays, we showed that one cadherin fragment, which contains CR7-11 (cadherin repeats 7-11), bound Cry11Aa and this binding was primarily through toxin domain II loops alpha8 and 2. Cadherin repeats CR8-11 but not CR7 bound Cry11Aa under non-denaturing conditions. Cry11Aa bound the cadherin fragment with high affinity with an apparent Kd of 16.7 nM. Finally we showed that this Cry11Aa-binding site could also be competed by Cry11Ba and Cry4Aa but not Cry4Ba. These results indicate that Aedes cadherin is possibly a receptor for Cry11A and, together with its ability to bind an ALP, suggest a similar mechanism of toxin action as previously proposed for lepidopteran insects. PMID:19732034

Chen, Jianwu; Aimanova, Karlygash G; Fernandez, Luisa E; Bravo, Alejandra; Soberon, Mario; Gill, Sarjeet S

2009-12-01

297

Study of the distribution and abundance of the eggs of Aedes aegypti and Aedes albopictus according to the habitat and meteorological variables, municipality of S?o Sebasti?o, S?o Paulo State, Brazil  

PubMed Central

Background This study focused on the distribution and abundance of the eggs of Aedes aegypti and Aedes albopictus. Methods Eighty ovitraps were exposed for four days of each month in peri- and intradomiciliary environments of 40 urban residences on 20 street blocks that were drawn monthly in Sebastião, SP, between February 2011 and February 2012. The monthly distribution of positive ovitrap indices (POI) and mean egg counts per trap (MET) of Ae. aegypti and Ae. albopictus were analyzed using the Kruskal-Wallis test, followed by the Dwass-Steel-Critchlow-Fligner (DSCF) test. Spearman's rank correlation coefficient and simple linear regression were used to determine the association between the meteorological variables of temperature and rainfall and the number of ovitraps with eggs and the egg count. Results The POI and MET of Ae. aegypti were higher in peridomiciliary premises. A positive correlation was found between the temperature and the number of ovitraps with eggs and the egg count of this species in domestic environments. There was no difference in the POI and MET of Ae. albopictus between the environments. A positive correlation was found between temperature and positive ovitraps of Ae. albopictus in peridomiciliary premises. The POI and MET of Ae. aegypti were higher than those of Ae. albopictus. Conclusions Peridomiciliary premises were the preferred environments for oviposition of Ae. aegypti. The use of ovitraps for surveillance and vector control is reiterated. PMID:24499530

2013-01-01

298

[Distribution of aedes (stegomyia) aegypti l. and aedes (stegomyia) albopictus skus. mosquitoes on the Black Sea coast of the Caucasus].  

PubMed

There is evidence that in the Black Sea coastal area, Ae.albopictus mosquitoes are encountered everywhere from N. Afon to Dzhubga over a length of 250 km of the coast and Ae.aegypti ones are from N. Afon to Agoi, Tuapse District (215 km). The Ae.albopictus mosquitoes have extended 44 km in length and 600 m in height in the eastern part of the coast (Krasnaya Polyana). PMID:23805493

Ganushkina, L A; Bezzhonova, O V; Patraman, I V; Tanygina, E Iu; Sergiev, V P

2013-01-01

299

[Sensitivity to dimilin (diflubenzuron) in a strain of Aedes (S) aegypti Linnneaus, 1762 and of Culex (C) quinquefasciatus Say, 1823 bred in the laboratory].  

PubMed

This paper studies the degree of sensitivity of larval Aedes (S) aegypti Linneaus, 1762 and Culex quinquefasciatus, Say, 1823, to dimilin (diflubenzuron-urea) with strains from Güines, in Havana province, which were bred in the laboratory. Tests were carried out in the period ranging from March, 1982 to March, 1983. The method used was the one standardized by the World Health Organization in 1980. The authors found susceptibility of A. aegypti to the product used with values of CL50 and CL95 of 0.045 mg/L and 0.255 mg/L respectively as well as physiologic resistance in Culex quinquefasciatus. PMID:2505345

Montada Dorta, D; Tang Chiong, R; Navarro Ortega, A; García Quiñones, F A

1989-01-01

300

Immunostaining for allatotropin and allatostatin-A and -C in the mosquitoes Aedes aegypti and Anopheles albimanus  

PubMed Central

Confocal laser-scanning microscopy was used to carry out a comparative study of the immunostaining for three families of neuropeptides, viz., allatostatin-A (AS-A), allatostatin-C (AS-C) and allatotropin (AT), in adult female mosquitoes of Aedes aegypti and Anopheles albimanus. The specific patterns of immunostaining for each of the three peptides were similar in both species. The antisera raised against AT, AS-A, and AS-C revealed intense immunoreactivity in the cells of each protocerebral lobe of the brain and stained cells in each of the ventral ganglia and neuronal projections innervating various thoracic and abdominal tissues. Only the AS-A antiserum labeled immunoreactive endocrine cells in the midgut. The distribution of the peptides supports the concept that they play multiple regulatory roles in both species. PMID:15909164

Hernandez-Martinez, Salvador; Li, Yiping; Lanz-Mendoza, Humberto; Rodriguez, Mario H.

2009-01-01

301

Use of anti-Aedes aegypti salivary extract antibody concentration to correlate risk of vector exposure and dengue transmission risk in Colombia.  

PubMed

Norte de Santander is a region in Colombia with a high incidence of dengue virus (DENV). In this study, we examined the serum concentration of anti-Aedes salivary gland extract (SGE) antibodies as a biomarker of DENV infection and transmission, and assessed the duration of anti-SGE antibody concentration after exposure to the vector ceased. We also determined whether SGE antibody concentration could differentiate between positive and negative DENV infected individuals and whether there are differences in exposure for each DENV serotype. We observed a significant decrease in the concentration of IgG antibodies at least 40 days after returning to an "Ae. aegypti-free" area. In addition, we found significantly higher anti-SGE IgG concentrations in DENV positive patients with some difference in exposure to mosquito bites among DENV serotypes. We conclude that the concentration of IgG antibodies against SGE is an accurate indicator of risk of dengue virus transmission and disease presence. PMID:24312537

Londono-Renteria, Berlin; Cardenas, Jenny C; Cardenas, Lucio D; Christofferson, Rebecca C; Chisenhall, Daniel M; Wesson, Dawn M; McCracken, Michael K; Carvajal, Daisy; Mores, Christopher N

2013-01-01

302

Field sampling rate of BG-sentinel traps for Aedes aegypti (Diptera: Culicidae) in suburban Cairns, Australia.  

PubMed

Mini-mark-release-recapture experiments were conducted in suburban Cairns, Australia to establish the sampling rate of the Biogents-Sentinel (BGS) trap for adult Aedes aegypti (L.). Small cohorts of marked mosquitoes (30 females and 15 males) were released at typical Cairns residences, and the number of marked mosquitoes recaptured in the BGS trap after 24 h was recorded. The sampling rate was compared between two seasons and two common housing styles (high-set 'Queenslander-style' timber and low-set brick houses), between old gravid and young nulliparous females, and between mosquitoes released in different areas of a house. Overall, the BGS traps recaptured a mean (+/- SEM) of 24.6% (+/- 1.9) of the released marked female mosquitoes in 24 h. The mean recapture rate for females was significantly higher in the dry season (30.4% +/- 2.8) compared with the wet (18.8% +/- 2.2). The overall recapture rates did not differ significantly between the two house types, but variability between the individual premises was high. An overall mean of 18.2% (+/- 1.7) of males was collected. Recapture rates of young nullipars and older gravid females were similar. These recapture rates can be used to estimate the population density of Ae. aegypti females in north Queensland, although it will provide an underestimate as trap sample was largely representative of mosquitoes present in the same area as the trap, and not from other areas of the house. PMID:22308768

Johnson, P H; Spitzauer, V; Ritchie, S A

2012-01-01

303

Diel sugar feeding and reproductive behaviours of Aedes aegypti mosquitoes in Trinidad: with implications for mass release of sterile mosquitoes.  

PubMed

Studies on the diel sugar feeding periodicity of male and female Aedes aegypti were conducted under laboratory conditions and monitored in single cages using the polyphagometer device and examined every 2h. Males mosquitoes displayed two peaks in sugar feeding, a small morning peak at 06.00-08.00 h (16% of sugar feeding) and a significant evening peak at 16.00-18.00 h (40% of sugar feeding). A similar pattern was observed among females: a small early morning peak (18% of sugar feeding) and a significant peak in the evening 16.00-18.00 h (42% of sugar feeding). Studies on the effects of sugar feeding on the excitation of males showed 100% erect antennal fibrillae after 36 h. In contrast, only 15% of the water-fed males responded. Laboratory studies on the effects of sugar feeding on the insemination rates of A. aegypti females showed similar inseminations rates among sugar and water fed males but after 4 days all water fed males died while the sugar fed males continued to survive and inseminate females. The synchronization of the male and female diel sugar feeding periodicity is discussed in the context of sterile insect techniques or genetic control methods. PMID:24076041

Chadee, Dave D; Sutherland, Joan M; Gilles, Jeremie R L

2014-04-01

304

Phylogeography of Aedes aegypti (Yellow Fever Mosquito) in South Florida: mtDNA Evidence for Human-Aided Dispersal  

PubMed Central

The invasive dengue vector Aedes aegypti has persisted for > 200 years in South Florida in the United States. We tested the hypotheses that Florida’s landscape creates dispersal barriers and corridors and that long-distance human-aided dispersal structures populations of Ae. aegypti. We evaluated the phylogeography of 362 individuals from Florida’s East and West Coasts with a 760-bp (418- and 342-bp fragments of ND5 and ND4, respectively) mitochondrial sequence. Populations from these two coasts were not significantly differentiated, suggesting that limited urbanization in central Florida is not a strong barrier to gene flow. Evidence for long-distance dispersal between Ft. Lauderdale and the West and Ft. Myers and the East indicates the importance of human-aided dispersal. West Coast populations showed no genetic differentiation, indicating that West Coast rivers and bays did not significantly impede gene flow. Phylogeographic analysis of haplotypes showed two distinct matrilines with no geographic patterns, suggesting multiple introductions or balancing selection. PMID:23918216

Damal, Kavitha; Murrell, Ebony G.; Juliano, Steven A.; Conn, Jan E.; Loew, Sabine S.

2013-01-01

305

Larvicidal efficacy of seed oils of Pterocarpus santalinoides and tropical Manihot species against Aedes aegypti and effects on aquatic fauna.  

PubMed

Botanical larvicides have featured prominently as alternative to synthetic chemical insecticides which are less degradable and toxic to non-target organisms. The larvicidal potentials of the seed oils of Pterocarpus santalinoides and Tropical Manihot species (TMS 30572) were investigated in the laboratory against larvae of Aedes aegypti. The seed oil of each plant was extracted using n-hexane and was graded into different concentrations; 30, 60, 90, 120 and 150 ppm. The toxicity of each of the concentrations was evaluated against 3rd instar larvae of A. aegypti and tadpoles (Buffo spp) as non target aquatic fauna. Both oils were toxic to the larvae though at higher concentrations (120 ppm and 150 ppm) after 24 hours of exposure. The oil of P. santalinoides was more toxic to the larvae (LC50 104.0 ppm and LC90 184.5 ppm) than oil of TMS (LC50 113.5 and LC90 201.2) but the difference in the lethal doses was not statistically significant (P > 0.05). However, mortality was not recorded at any of the graded concentrations in both oils against tadpoles. The results therefore suggest that the seed oils of both plants could be incorporated as botanical insecticides against mosquito vectors with high safety to non-target organisms. PMID:20734705

Adeleke, M A; Popoola, S A; Agbaje, W B; Adewale, B; Adeoye, M D; Jimoh, W A

2009-10-01

306

Comparative investigation of Umbellularia californica and Laurus nobilis leaf essential oils and identification of constituents active against Aedes aegypti.  

PubMed

Umbellularia californica (California bay laurel) and Laurus nobilis (Mediterranean bay laurel) leaves may be mistaken or used as a substitute on the market due to their morphological similarity. In this study, a comparison of anatomical and chemical features and biological activity of both plants is presented. L. nobilis essential oil biting deterrent and larvicidal activity were negligible. On the other hand, U. californica leaf oil showed biting deterrent activity against Aedes aegypti . The identified active repellents was thymol, along with (-)-umbellulone, 1,8-cineole, and (-)-?-terpineol. U. californica essential oil also demonstrated good larvicidal activity against 1-day-old Ae. aegypti larvae with a LD50 value of 52.6 ppm. Thymol (LD50 = 17.6 ppm), p-cymene, (-)-umbellulone, and methyleugenol were the primary larvicidal in this oil. Umbellulone was found as the principal compound (37%) of U. californica essential oil, but was not present in L. nobilis essential oil. Umbellulone mosquito activity is here reported for the first time. PMID:24266426

Tabanca, Nurhayat; Avonto, Cristina; Wang, Mei; Parcher, Jon F; Ali, Abbas; Demirci, Betul; Raman, Vijayasankar; Khan, Ikhlas A

2013-12-18

307

Chemical constituents and larvicidal potential of Feronia limonia leaf essential oil against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus.  

PubMed

In the present investigation, the leaf essential oil of Feronia limonia was evaluated for chemical constituents and mosquito larvicidal activity against the larvae of Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. GC and GC-MS analyses revealed that the essential oil contain 51 compounds. Estragole (34.69 %) and ?-pinene(23.59 %) were identified as the major constituents followed by methyl (Z)-caryophyllene (11.05 %), eugenol (6.50 %), linalool (3.97 %), phytol (3.27 %), sabinene (2.41 %) and limonene (2.27 %). Larval mortality was observed after 12 and 24 h of exposure period. The oil showed remarkable larvicidal activity against A. stephensi (LC(50)?=?38.93 and LC(90)?=?108.64 ppm (after 12 h); LC(50)?=?15.03 and LC(90)?=?36.69 ppm (after 24 h)), A. aegypti (LC(50)?=?37.60 and LC(90)?=?104.69 ppm (after 12 h); LC(50)?=?11.59 and LC(90)?=?42.95 ppm (after 24 h)) and C. quinquefasciatus (LC(50)?=?52.08 and LC(90)?=?124.33 ppm (after 12 h); LC(50)?=?22.49 and LC(90)?=?60.90 ppm (after 24 h)). Based on the results, the essential oil of F. limonia can be considered as a new source of larvicide for the control of vector mosquitoes. PMID:23160893

Senthilkumar, A; Jayaraman, M; Venkatesalu, V

2013-03-01

308

The synergistic effects of insecticidal essential oils and piperonyl butoxide on biotransformational enzyme activities in Aedes aegypti (Diptera: Culicidae).  

PubMed

The biochemical mechanisms underlying the increased toxicity of several plant essential oils (thymol, eugenol, pulegone, terpineol, and citronellal) against fourth instar of Aedes aegypti L. when exposed simultaneously with piperonyl butoxide (PBO) were examined. Whole body biotransformational enzyme activities including cytochrome P450-mediated oxidation (ethoxyresorufin O-dethylase [EROD]), glutathione S-transferase (GST), and beta-esterase activity were measured in control, essential oil-exposed only (single chemical), and essential oil + PBO (10 mg/liter) exposed larvae. At high concentrations, thymol, eugenol, pulegone, and citronellal alone reduced EROD activity by 5-25% 16 h postexposure. Terpineol at 10 mg/liter increased EROD activity by 5 +/- 1.8% over controls. The essential oils alone reduced GST activity by 3-20% but PBO exposure alone did not significantly affect the activity of any of the measured enzymes. All essential oils in combination with PBO reduced EROD activity by 58-76% and reduced GST activity by 3-85% at 16 h postexposure. This study indicates a synergistic interaction between essential oils and PBO in inhibiting the cytochrome P450 and GST detoxification enzymes in Ae. aegypti. PMID:22679869

Waliwitiya, Ranil; Nicholson, Russell A; Kennedy, Christopher J; Lowenberger, Carl A

2012-05-01

309

Transcription profiling of resistance to Bti toxins in the mosquito Aedes aegypti using next-generation sequencing.  

PubMed

The control of mosquitoes transmitting infectious diseases relies mainly on the use of chemical insecticides. However, resistance to most chemical insecticides threatens mosquito control programs. In this context, the spraying of toxins produced by the bacteria Bacillus thuringiensis subsp. israelensis (Bti) in larval habitats represents an alternative to chemical insecticides and is now widely used for mosquito control. Recent studies suggest that resistance of mosquitoes to Bti toxin may occur locally but mechanisms have not been characterized so far. In the present study, we investigated gene transcription level variations associated with Bti toxin resistance in the mosquito Aedes aegypti using a next-generation sequencing approach. More than 6 million short cDNA tags were sequenced from larvae of two strains sharing the same genetic background: a Bti toxins-resistant strain and a susceptible strain. These cDNA tags were mapped with a high coverage (308 reads per position in average) to more than 6000 genes of Ae. aegypti genome and used to quantify and compare the transcription level of these genes between the two mosquito strains. Among them, 86 genes were significantly differentially transcribed more than 4-fold in the Bti toxins resistant strain comparatively to the susceptible strain. These included gene families previously associated with Bti toxins resistance such as serine proteases, alkaline phosphatase and alpha-amylase. These results are discussed in regards of potential Bti toxins resistance mechanisms in mosquitoes. PMID:22115744

Paris, Margot; Melodelima, Christelle; Coissac, Eric; Tetreau, Guillaume; Reynaud, Stephane; David, Jean-Philippe; Despres, Laurence

2012-02-01

310

Fitness evaluation of two Brazilian Aedes aegypti field populations with distinct levels of resistance to the organophosphate temephos.  

PubMed

In Brazil, decades of dengue vector control using organophosphates and pyrethroids have led to dissemination of resistance. Although these insecticides have been employed for decades against Aedes aegypti in the country, knowledge of the impact of temephos resistance on vector viability is limited. We evaluated several fitness parameters in two Brazilian Ae. aegypti populations, both classified as deltamethrin resistant but with distinct resistant ratios (RR) for temephos. The insecticide-susceptible Rockefeller strain was used as an experimental control. The population presenting the higher temephos resistance level, Aparecida de Goiânia, state of Goiás (RR(95) of 19.2), exhibited deficiency in the following four parameters: blood meal acceptance, amount of ingested blood, number of eggs and frequency of inseminated females. Mosquitoes from Boa Vista, state of Roraima, the population with lower temephos resistance level (RR(95) of 7.4), presented impairment in only two parameters, blood meal acceptance and frequency of inseminated females. These results indicate that the overall fitness handicap was proportional to temephos resistance levels. However, it is unlikely that these disabilities can be attributed solely to temephos resistance, since both populations are also resistant to deltamethrin and harbour the kdr allele, which indicates resistance to pyrethroids. The effects of reduced fitness in resistant populations are discussed. PMID:23147149

Belinato, Thiago Affonso; Martins, Ademir Jesus; Valle, Denise

2012-11-01

311

Temephos resistance and esterase activity in the mosquito Aedes aegypti in Havana, Cuba increased dramatically between 2006 and 2008.  

PubMed

Aedes aegypti (L.) (Diptera: Culicidae) control programmes in Cuba rely on the application of the organophosphate temephos for larval control. Hence, the monitoring of resistance to this insecticide is an essential component of such programmes. Here, 15 field populations from different municipalities of Havana City were assayed for resistance to temephos. High levels of resistance were detected in all strains and resistance ratios were highly correlated with esterase activity (P = 0.00001). Populations from three municipalities were tested in both 2006 and 2008; resistance and esterase activities both significantly increased during this 2-year period. Synergist studies demonstrated that neither glutathione transferases nor monooxygenases were associated with the increase in resistance to temephos in this period. The duration of the efficacy of commercial formulations of temephos in controlling Ae. aegypti populations in Havana City was reduced by the high level of temephos resistance observed; hence these data are of clear operational significance for the dengue control programme in Cuba. New integrated strategies to avoid further increases in temephos resistance in Cuba are necessary. PMID:21501201

Bisset, J A; Rodríguez, M M; Ricardo, Y; Ranson, H; Pérez, O; Moya, M; Vázquez, A

2011-09-01

312

Cadherin binding is not a limiting step for Bacillus thuringiensis subsp. israelensis Cry4Ba toxicity to Aedes aegypti larvae  

PubMed Central

Bacillus thuringiensis subsp. israelensis produces three Cry toxins (Cry4Aa, Cry4Ba and Cry11Aa) that are active against Aedes aegypti larvae. The identification of the rate-limiting binding steps of Cry toxins that are used for insect control in the field, such as those of B. thuringiensis subsp. israelensis, should provide targets for improving insecticides against important insect pests. Previous studies showed that Cry11Aa binds to cadherin receptor fragment CR7–11 (cadherin repeats 7–11) with high affinity. Binding to cadherin has been proposed to facilitate Cry toxin oligomer formation. In the present study, we show that Cry4Ba binds to CR7–11 with 9-fold lower binding affinity compared with Cry11Aa. Oligomerization assays showed that Cry4Ba is capable of forming oligomers when proteolytically activated in vitro in the absence of the CR7–11 fragment in contrast with Cry11Aa that formed oligomers only in the presence of CR7–11. Pore-formation assays in planar lipid bilayers showed that Cry4Ba oligomers were proficient in opening ion channels. Finally, silencing the cadherin gene by dsRNA (double-stranded RNA) showed that silenced larvae were more tolerant to Cry11Aa in contrast with Cry4Ba, which showed similar toxic levels to those of control larvae. These findings show that cadherin binding is not a limiting step for Cry4Ba toxicity to A. aegypti larvae. PMID:22329749

Rodriguez-Almazan, Claudia; Reyes, Esmeralda Z.; Zuniga-Navarrete, Fernando; Munoz-Garay, Carlos; Gomez, Isabel; Evans, Amy M.; Likitvivatanavong, Supaporn; Bravo, Alejandra; Gill, Sarjeet S.; Soberon, Mario

2013-01-01

313

Cadherin binding is not a limiting step for Bacillus thuringiensis subsp. israelensis Cry4Ba toxicity to Aedes aegypti larvae.  

PubMed

Bacillus thuringiensis subsp. israelensis produces three Cry toxins (Cry4Aa, Cry4Ba and Cry11Aa) that are active against Aedes aegypti larvae. The identification of the rate-limiting binding steps of Cry toxins that are used for insect control in the field, such as those of B. thuringiensis subsp. israelensis, should provide targets for improving insecticides against important insect pests. Previous studies showed that Cry11Aa binds to cadherin receptor fragment CR7-11 (cadherin repeats 7-11) with high affinity. Binding to cadherin has been proposed to facilitate Cry toxin oligomer formation. In the present study, we show that Cry4Ba binds to CR7-11 with 9-fold lower binding affinity compared with Cry11Aa. Oligomerization assays showed that Cry4Ba is capable of forming oligomers when proteolytically activated in vitro in the absence of the CR7-11 fragment in contrast with Cry11Aa that formed oligomers only in the presence of CR7-11. Pore-formation assays in planar lipid bilayers showed that Cry4Ba oligomers were proficient in opening ion channels. Finally, silencing the cadherin gene by dsRNA (double-stranded RNA) showed that silenced larvae were more tolerant to Cry11Aa in contrast with Cry4Ba, which showed similar toxic levels to those of control larvae. These findings show that cadherin binding is not a limiting step for Cry4Ba toxicity to A. aegypti larvae. PMID:22329749

Rodríguez-Almazán, Claudia; Reyes, Esmeralda Z; Zúñiga-Navarrete, Fernando; Muñoz-Garay, Carlos; Gómez, Isabel; Evans, Amy M; Likitvivatanavong, Supaporn; Bravo, Alejandra; Gill, Sarjeet S; Soberón, Mario

2012-05-01

314

Estimation of Aedes aegypti (Diptera: Culicidae) population size and adult male survival in an urban area in Panama.  

PubMed

Traditional mosquito control strategies rely heavily on the use of chemical insecticides. However, concerns about the efficiency of traditional control methods, environmental impact and emerging pesticide resistance have highlighted the necessity for developing innovative tools for mosquito control. Some novel strategies, including release of insects carrying a dominant lethal gene (RIDL®), rely on the sustained release of modified male mosquitoes and therefore benefit from a thorough understanding of the biology of the male of the species. In this report we present the results of a mark-release-recapture study aimed at: (i) establishing the survival in the field of laboratory-reared, wild-type male Aedes aegypti and (b) estimating the size of the local adult Ae. aegypti population. The study took place in Panama, a country where recent increases in the incidence and severity of dengue cases have prompted health authorities to evaluate alternative strategies for vector control. Results suggest a life expectancy of 2.3 days for released male mosquitoes (confidence interval: 1.78-2.86). Overall, the male mosquito population was estimated at 58 males/ha (range 12-81 males/ha), which can be extrapolated to an average of 0.64 pupae/person for the study area. The practical implications of these results are discussed. PMID:25410991

Neira, Marco; Lacroix, Renaud; Cáceres, Lorenzo; Kaiser, Paul E; Young, Josue; Pineda, Lleysa; Black, Isaac; Sosa, Nestor; Nimmo, Derric; Alphey, Luke; McKemey, Andrew

2014-11-01

315

Male Mating History and Body Size Influence Female Fecundity and Longevity of the Dengue Vector Aedes aegypti  

PubMed Central

Male reproductive success is dependent on insemination success and reproductive output. During mating, male mosquitoes transfer not just sperm, but also seminal fluid proteins that may have profound effects on mated female biology and behavior. In this study, we investigated the role of male body size and mating history on semen depletion, female longevity and reproductive success in Aedes aegypti L. Small and large males were mated in rapid succession with up to five females. Our results indicate that large males had greater mating capacity than small males. A reduction in fecundity by more than 50% was observed in females that were fourth to mate with small males in comparison to females that mated earlier in sequence. For females mated to large males, this reduction became evident for females that mated fifth in sequence. No loss of fertility (measured as hatch rate) was observed in females that were 3rd-5th in mating sequence compared to females mated to virgin males. When females were maintained on a low-quality (5% sucrose) diet, those mated to virgin males had a greater longevity compared to females mated third in sequence. We conclude that small males experience more rapid seminal depletion than large males, and discuss the role of semen depletion in the mated female. Our results contribute towards a better understanding of the complexity of Ae. aegypti mating biology and provide refined estimates of mating capacity for genetic control efforts. PMID:21485355

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

2014-01-01

316

Aging Field Collected Aedes aegypti to Determine Their Capacity for Dengue Transmission in the Southwestern United States  

PubMed Central

Aedes aegypti, the primary vector of dengue virus, is well established throughout urban areas of the Southwestern US, including Tucson, AZ. Local transmission of the dengue virus, however, has not been reported in this area. Although many factors influence the distribution of the dengue virus, we hypothesize that one contributing factor is that the lifespan of female Ae. aegypti mosquitoes in the Southwestern US is too short for the virus to complete development and be transmitted to a new host. To test this we utilized two age grading techniques. First, we determined parity by analyzing ovarian tracheation and found that only 40% of Ae. aegypti females collected in Tucson, AZ were parous. The second technique determined transcript levels of an age-associated gene, Sarcoplasmic calcium-binding protein 1 (SCP-1). SCP-1 expression decreased in a predictable manner as the age of mosquitoes increased regardless of rearing conditions and reproductive status. We developed statistical models based on parity and SCP-1 expression to determine the age of individual, field collected mosquitoes within three age brackets: nonvectors (0–5 days post-emergence), unlikely vectors (6–14 days post-emergence), and potential vectors (15+ days post-emergence). The statistical models allowed us to accurately group individual wild mosquitoes into the three age brackets with high confidence. SCP-1 expression levels of individual, field collected mosquitoes were analyzed in conjunction with parity status. Based on SCP-1 transcript levels and parity data, 9% of collected mosquitoes survived more than 15 days post emergence. PMID:23077536

Joy, Teresa K.; Jeffrey Gutierrez, Eileen H.; Ernst, Kacey; Walker, Kathleen R.; Carriere, Yves; Torabi, Mohammad; Riehle, Michael A.

2012-01-01

317

Novel, Meso-Substituted Cationic Porphyrin Molecule for Photo-Mediated Larval Control of the Dengue Vector Aedes aegypti  

PubMed Central

Background Control of the mosquito vector population is the most effective strategy currently available for the prevention of dengue fever and the containment of outbreaks. Photo-activated oxidants may represent promising tools for developing effective, safe and ecofriendly novel larvicides. The purpose of this study was to evaluate the potential of the synthetic meso-substituted porphyrin meso-tri(N-methylpyridyl), meso-mono(N-tetradecylpyridyl)porphine (C14) as a photoactivatable larvicide against the dengue vector Aedes (Stegomyia) aegypti. Methodology The photophysical and photochemical properties of the C14 molecule were assessed spectrophotometrically. Photomediated larvicidal efficacy, route of intake and site of action were determined on Ae. aegypti larvae by laboratory bioassays and fluorescence microscopy. Using powdered food pellet for laboratory rodents (a common larval food used in the laboratory) as a carrier for C14, loading-release dynamics, larvicidal efficacy and residual activity of the C14-carrier complex were investigated. Main Findings The C14 molecule was found to exert a potent photosensitizing activity on Ae. aegypti larvae. At irradiation intervals of 12 h and 1 h, at a light intensity of 4.0 mW/cm2, which is 50–100 times lower than that of natural sunlight, LC50 values of 0.1 µM (0.15 mg/l) and 0.5 µM (0.77 mg/l) were obtained, respectively. The molecule was active after ingestion by the larvae and caused irreversible, lethal damage to the midgut and caecal epithelia. The amphiphilic nature of C14 allowed a formulate to be produced that not only was as active against the larvae as C14 in solution, but also possessed a residual activity of at least two weeks, in laboratory conditions. Conclusions The meso-substituted synthetic porphyrin C14, thanks to its photo-sensitizing properties represents an attractive candidate for the development of novel photolarvicides for dengue vector control. PMID:22206031

Lucantoni, Leonardo; Magaraggia, Michela; Lupidi, Giulio; Ouedraogo, Robert Kossivi; Coppellotti, Olimpia; Esposito, Fulvio; Fabris, Clara; Jori, Giulio; Habluetzel, Annette

2011-01-01

318

Disruption of Aedes aegypti Olfactory System Development through Chitosan/siRNA Nanoparticle Targeting of semaphorin-1a  

PubMed Central

Despite the devastating impact of mosquito-borne illnesses on human health, surprisingly little is known about mosquito developmental biology, including development of the olfactory system, a tissue of vector importance. Analysis of mosquito olfactory developmental genetics has been hindered by a lack of means to target specific genes during the development of this sensory system. In this investigation, chitosan/siRNA nanoparticles were used to target semaphorin-1a (sema1a) during olfactory system development in the dengue and yellow fever vector mosquito Aedes aegypti. Immunohistochemical analyses and anterograde tracing of antennal sensory neurons, which were used to track the progression of olfactory development in this species, revealed antennal lobe defects in sema1a knockdown fourth instar larvae. These findings, which correlated with a larval odorant tracking behavioral phenotype, identified previously unreported roles for Sema1a in the developing insect larval olfactory system. Analysis of sema1a knockdown pupae also revealed a number of olfactory phenotypes, including olfactory receptor neuron targeting and projection neuron defects coincident with a collapse in the structure and shape of the antennal lobe and individual glomeruli. This study, which is to our knowledge the first functional genetic analysis of insect olfactory development outside of D. melanogaster, identified critical roles for Sema1a during Ae. aegypti larval and pupal olfactory development and advocates the use of chitosan/siRNA nanoparticles as an effective means of targeting genes during post-embryonic Ae. aegypti development. Use of siRNA nanoparticle methodology to understand sensory developmental genetics in mosquitoes will provide insight into the evolutionary conservation and divergence of key developmental genes which could be exploited in the development of both common and species-specific means for intervention. PMID:23696908

Mysore, Keshava; Flannery, Ellen M.; Tomchaney, Michael; Severson, David W.; Duman-Scheel, Molly

2013-01-01

319

[Population dynamics of the immature stages of Aedes aegypti (Diptera: Culicidae), vector of dengue: a longitudinal study (1996-2000)].  

PubMed

A four year study was conducted on a natural population of immature stages of Aedes aegypti after the re-invasion of Argentina by this vector in 1987. Thirty six plastic containers with 700 ml of dechlorinated water were placed in the La Plata Zoological Garden, La Plata, Argentina. A strip of filter paper around each container was added to facilitate egg counting. Eggs, larvae and pupae were counted weekly in each container from September, 1996 to August, 2000. After egg counting, papers were submerged to facilitate egg hatching and a new paper was placed in each container. Presence of A. aegypti immature stages was recorded from December-January to June during each of the four years of this study. In 1997, 13,105 eggs, 7,978 larvae and 1,476 pupae were registered with 54.7 % positive containers; during 1998, 8,194 eggs, 668 larvae and 142 pupae were recorded with 28.3 % positive containers; 13,510 eggs, 3,690 larvae and 743 pupae were registered during 1999 with 56.7 % positive containers; and 16,327 eggs, 4,669 larvae and 715 pupae during 2000 with 59.3 % of containers with presence of A. aegypti. Egg number and hatching rate were drastically reduced in 1998 when temperatures from December to May were 1 to 2.5 degrees C lower than the other years of this study. These colder than usual temperatures in the summer of 1998 were a consequence of the El Niño event. PMID:18491640

Micieli, María V; García, Juan J; Achinelly, María F; Martí, Gerardo A

2006-09-01

320

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

PubMed Central

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

2014-01-01

321

Insecticide resistance in the dengue vector Aedes aegypti from Martinique: distribution, mechanisms and relations with environmental factors.  

PubMed

Dengue is an important mosquito borne viral disease in Martinique Island (French West Indies). The viruses responsible for dengue are transmitted by Aedes aegypti, an indoor day-biting mosquito. The most effective proven method for disease prevention has been by vector control by various chemical or biological means. Unfortunately insecticide resistance has already been observed on the Island and recently showed to significantly reduce the efficacy of vector control interventions. In this study, we investigated the distribution of resistance and the underlying mechanisms in nine Ae. aegypti populations. Statistical multifactorial approach was used to investigate the correlations between insecticide resistance levels, associated mechanisms and environmental factors characterizing the mosquito populations. Bioassays revealed high levels of resistance to temephos and deltamethrin and susceptibility to Bti in the 9 populations tested. Biochemical assays showed elevated detoxification enzyme activities of monooxygenases, carboxylesterases and glutathione S-tranferases in most of the populations. Molecular screening for common insecticide target-site mutations, revealed the presence of the "knock-down resistance" V1016I Kdr mutation at high frequency (>87%). Real time quantitative RT-PCR showed the potential involvement of several candidate detoxification genes in insecticide resistance. Principal Component Analysis (PCA) performed with variables characterizing Ae. aegypti from Martinique permitted to underline potential links existing between resistance distribution and other variables such as agriculture practices, vector control interventions and urbanization. Insecticide resistance is widespread but not homogeneously distributed across Martinique. The influence of environmental and operational factors on the evolution of the resistance and mechanisms are discussed. PMID:22363529

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

2012-01-01

322

The effect of host type on movement patterns of Aedes aegypti (Diptera: Culicidae) into and out of experimental huts in Thailand.  

PubMed

Flight behavior studies were carried out from December 2004 through February 2005 at two sites in Thailand to compare the movement patterns of Aedes aegypti into and out of experimental huts baited with a human host, dog host, or without a host using a mark-release-recapture study design. Studies were conducted in isolated villages of Kanchanaburi and Chiang Mai Provinces, Thailand. In the presence of a human host only 4.9% (39/800) of the Ae. aegypti females departed the hut as compared to 46.5% (372/800) when a dog was present. There was no significant difference in the numbers of Ae. aegypti exiting when comparing dog to no host. A peak in exiting behavior in the absence of any host (human or dog) was observed between 1400-1700 h. Ingress behavior was much stronger when a human host was present in the hut with the peak of entering occurring in the morning (0830-1130 h) compared to 1000-1200 h without a host. Overall, significant differences between the two host types were observed with Ae. aegypti females being more attracted to humans (p < 0.05) than dogs. There was no significant difference between numbers of Ae. aegypti entering the hut baited with a dog and the hut containing no host source. The experimental hut design used in the present study can serve as a protocol for testing the exiting and entering behavior of Ae. aegypti in response to chemical compounds. PMID:17249349

Suwonkerd, Wannapa; Mongkalangoon, Piti; Parbaripai, Atchariya; Grieco, John; Achee, Nicole; Roberts, Donald; Chareonviriyaphap, Theeraphap

2006-12-01

323

Efficient transformation of the yellow fever mosquito Aedes aegypti using the piggyBac transposable element vector pBac[3xP3-EGFP afm  

Microsoft Academic Search

We report efficient germ-line transformation in the yellow fever mosquito Aedes aegypti accomplished using the piggyBac transposable element vector pBac[3xP3-EGFP afm]. Two transgenic lines were established and characterized; each contained the Vg-Defensin A transgene with strong eye-specific expression of the enhanced green fluorescent protein (EGFP) marker gene regulated by the artificial 3xP3 promoter. Southern blot hybridization and inverse PCR analyses

V. Kokoza; A. Ahmed; E. A. Wimmer; A. S. Raikhel

2001-01-01

324

Identification of a Chemosensory Receptor from the Yellow Fever Mosquito, Aedes aegypti, that is Highly Conserved and Expressed in Olfactory and Gustatory Organs  

Microsoft Academic Search

Aedes aegypti is a highly anthropophilic mosquito responsible for the transmission of dengue and yellow fever around the world. Like other mosquitoes, the biting and host preference behaviors of this disease vector are largely influenced by its sense of smell, which is presumably facilitated by G protein-coupled receptor signaling cascades. Here, we report the identification and characterization of AaOr7, the

A. C. A. Melo; Michael Rützler; R. Jason Pitts; Laurence J. Zwiebel

2004-01-01

325

Bioefficacy of Plumbago zeylanica (Plumbaginaceae) and Cestrum nocturnum (Solanaceae) plant extracts against Aedes aegypti (Diptera: Culicide) and nontarget fish Poecilia reticulata  

Microsoft Academic Search

In a search for natural products that could be used to control the vectors of tropical diseases, extracts of medicinal plants\\u000a Plumbago zeylanica and Cestrum nocturnum have been tested for larvicidal activity against second, third, and fourth instar larvae of Aedes aegypti. The LC50 values of all the extracts in different solvents of both the plants were less than 50 ppm

Chandrashekhar D. Patil; Satish V. Patil; Bipinchandra K. Salunke; Rahul B. Salunkhe

2011-01-01

326

Larvicidal potential of silver nanoparticles synthesized using fungus Cochliobolus lunatus against Aedes aegypti (Linnaeus, 1762) and Anopheles stephensi Liston (Diptera; Culicidae)  

Microsoft Academic Search

Larvicides play a vital role in controlling mosquitoes in their breeding sites. The present study was carried out to establish\\u000a the larvicidal activities of mycosynthesized silver nanoparticles (AgNPs) against vectors: Aedes aegypti and Anopheles stephensi responsible for diseases of public health importance. The AgNPs synthesized by filamentous fungus Cochliobolus lunatus, characterized by UV–Vis spectrophotometry, Fourier transform infrared spectroscopy, X-ray diffraction,

Rahul B. Salunkhe; Satish V. Patil; Chandrashekhar D. Patil; Bipinchandra K. Salunke

327

First Attempt To Validate Human IgG Antibody Response to Nterm-34kDa Salivary Peptide as Biomarker for Evaluating Exposure to Aedes aegypti Bites  

PubMed Central

Background Much effort is being devoted for developing new indicators to evaluate the human exposure to Aedes mosquito bites and the risk of arbovirus transmission. Human antibody (Ab) responses to mosquito salivary components could represent a promising tool for evaluating the human-vector contact. Methodology/Principal findings To develop a specific biomarker of human exposure to Aedes aegypti bites, we measured IgG Ab response to Ae. aegypti Nterm-34 kDa salivary peptide in exposed children in 7 villages of Southern Benin (West Africa). Results showed that specific IgG response presented high inter-individual heterogeneity between villages. IgG response was associated with rainfall and IgG level increased from dry (low exposure) to rainy (high exposure) seasons. These findings indicate that IgG Ab to Nterm-34 kDa salivary peptide may represent a reliable biomarker to detect variation in human exposure to Ae. aegypti bites. Conclusion/Significance This preliminary study highlights the potential use of Ab response to this salivary peptide for evaluating human exposure to Ae. aegypti. This biomarker could represent a new promising tool for assessing the risk of arbovirus transmission and for evaluating the efficacy of vector control interventions. PMID:23166852

Elanga Ndille, Emmanuel; Doucoure, Souleymane; Damien, Georgia; Mouchet, Francois; Drame, Papa Makhtar; Cornelie, Sylvie; Noukpo, Herbert; Yamadjako, Sandra; Djenontin, Armel; Moiroux, Nicolas; Misse, Dorothee; Akogbeto, Martin; Corbel, Vincent; Henry, Marie-Claire; Chandre, Fabrice; Baldet, Thierry; Remoue, Franck

2012-01-01

328

Effects of extract of soapnut Sapindus emarginatus on esterases and phosphatases of the vector mosquito, Aedes aegypti (Diptera: Culicidae).  

PubMed

Our earlier investigations with kernels from the soapnut Sapindus emarginatus revealed it as a new source of botanical biocide with potent antimosquito activity, as evident from the proven unique ability of the aqueous kernel extract to kill all the developmental stages of three important vector mosquito species, Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. This extract was also found to be safe for two non-target aquatic insects. As a sequel to these findings, we have further examined quantitative and qualitative changes in total proteins, esterases, and phosphatases in whole body homogenates of fourth instar larvae and pupae of A. aegypti exposed to this extract at an appropriate threshold time for its lethal effect to gain insights into the impact of the botanical biocide on biochemical characteristics of the target vector mosquito at two distinct developmental stages. The profiles of proteins, esterases (acetylcholinesterse, ?- and ?-carboxylesterases), and phosphatases (acid and alkaline) exhibited distinct patterns of variation during normal development of fourth instar larvae and pupae, indicating intrinsic difference in biochemical features between these two developmental stages of A. aegypti. Upon exposure of the larvae to the extract, significant reduction in the activities of acetylcholinesterse, ?-carboxylesterase, and acid phosphatases were recorded, whereas the total proteins, ?-carboxylesterase and alkaline phosphatase activities were unaffected. By contrast, only alkaline phosphatase activity was significantly affected in pupae exposed to the extract. Analysis of these enzymes in native PAGE revealed that they exist in isoforms in both the larvae and pupae. The alterations in the levels of enzymatic activities observed from the quantitative assays of various enzymes were reflected by the respective zymograms with perceptible differences in the intensity and the number of bands detected especially with ?-carboxylesterase, acid and alkaline phosphatase activity between the control and exposed test organisms. Despite the fact that the soapnut kernel extract causes mortality of both the larvae and pupae of A. aegypti, the findings of this study demonstrate that the impact of this extract is most pronounced in various enzyme profiles of the larvae rather than the pupae. Such discrepancy implicates the presence of unique biochemical mechanisms in the pupae of mosquito for detoxification of botanical biocides. PMID:21251906

Koodalingam, Arunagirinathan; Mullainadhan, Periasamy; Arumugam, Munusamy

2011-04-01

329

The mosquito Aedes aegypti has a large genome size and high transposable element load but contains a low proportion of transposon-specific piRNAs  

PubMed Central

Background The piRNA pathway has been shown in model organisms to be involved in silencing of transposons thereby providing genome stability. In D. melanogaster the majority of piRNAs map to these sequences. The medically important mosquito species Aedes aegypti has a large genome size, a high transposon load which includes Miniature Inverted repeat Transposable Elements (MITES) and an expansion of the piRNA biogenesis genes. Studies of transgenic lines of Ae. aegypti have indicated that introduced transposons are poorly remobilized and we sought to explore the basis of this. We wished to analyze the piRNA profile of Ae. aegypti and thereby determine if it is responsible for transposon silencing in this mosquito. Results Estimated piRNA sequence diversity was comparable between Ae. aegypti and D. melanogaster, but surprisingly only 19% of mosquito piRNAs mapped to transposons compared to 51% for D. melanogaster. Ae. aegypti piRNA clusters made up a larger percentage of the total genome than those of D. melanogaster but did not contain significantly higher percentages of transposon derived sequences than other regions of the genome. Ae. aegypti contains a number of protein coding genes that may be sources of piRNA biogenesis with two, traffic jam and maelstrom, implicated in this process in model organisms. Several genes of viral origin were also targeted by piRNAs. Examination of six mosquito libraries that had previously been transformed with transposon derived sequence revealed that new piRNA sequences had been generated to the transformed sequences, suggesting that they may have stimulated a transposon inactivation mechanism. Conclusions Ae. aegypti has a large piRNA complement that maps to transposons but primarily gene sequences, including many viral-derived sequences. This, together the more uniform distribution of piRNA clusters throughout its genome, suggest that some aspects of the piRNA system differ between Ae. aegypti and D. melanogaster. PMID:22171608

2011-01-01

330

Detection of dengue viral RNA in Aedes aegypti (Diptera: Culicidae) exposed to sticky lures using reverse-transcriptase polymerase chain reaction.  

PubMed

Active surveillance for dengue (DEN) virus infected mosquitoes can be an effective way to predict the risk of dengue infection in a given area. However, doing so may pose logistical problems if mosquitoes must be kept alive or frozen fresh to detect DEN virus. In an attempt to simplify mosquito processing, we evaluated the usefulness of a sticky lure and a seminested reverse-transcriptase polymerase chain reaction assay (RT-PCR) for detecting DEN virus RNA under laboratory conditions using experimentally infected Aedes aegypti (L.) mosquitoes. In the first experiment, 40 male mosquitoes were inoculated with 0.13 microl of a 10(4) pfu/ml DEN-2 stock solution. After a 7-d incubation period, the mosquitoes were applied to the sticky lure and kept at room temperatures of 23-30 degrees C. Following 7, 10, 14, and 28 d application, 10 mosquitoes each were removed from the lure, pooled, and assayed for virus. DEN virus nucleic acid was clearly detectable in all pools up to 28 d after death. A second study evaluated sensitivity and specificity using one, two, and five DEN-infected mosquitoes removed after 7,10, 14, 21, and 30 d application and tested by RT-PCR. All four DEN serotypes were individually inoculated in mosquitoes and evaluated using the same procedures as experiment 1. The four serotypes were detectable in as few as one mosquito 30 d after applications to the lure with no evidence of cross-reactivity. The combination of sticky lures and RT-PCR show promise for mosquito and dengue virus surveillance and warrant further evaluation. PMID:11580045

Bangs, M J; Tan, R; Listiyaningsih, E; Kay, B H; Porter, K R

2001-09-01

331

Green synthesis of silver nanoparticles using Sida acuta (Malvaceae) leaf extract against Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti (Diptera: Culicidae).  

PubMed

Mosquitoes act as a vector for most of the life-threatening diseases like malaria, yellow fever, dengue fever, chikungunya fever, filariasis, encephalitis, West Nile Virus infection, etc. Under the Integrated Mosquito Management, 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 nontarget 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 nontoxic, easily available at affordable prices, biodegradable, and show broad-spectrum target-specific activities against different species of vector mosquitoes. In the present study, the larvicidal activity of silver nanoparticles (AgNPs) synthesized using Sida acuta plant leaf extract against late third instar larvae of Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti was determined. Range of concentrations of synthesized AgNPs (10, 20, 30, 40, and 50 ?g/mL) and aqueous leaf extract (50, 100, 150, 200, and 250 ?g/mL) were tested against the larvae of C. quinquefasciatus, A. stephensi and A. aegypti. The synthesized AgNPs from S. acuta leaf were highly toxic than crude leaf aqueous extract in three important vector mosquito species. The results were recorded from UV-Vis spectrum, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy analysis. Larvae were exposed to varying concentrations of aqueous crude extract and synthesized AgNPs for 24 h. Considerable mortality was evident after the treatment of S. acuta for all three important vector mosquitoes. The LC50 and LC90 values of S. acuta aqueous leaf extract appeared to be most effective against A. stephensi (LC50, 109.94 ?g/mL and LC90, 202.42 ?g/mL) followed by A. aegypti LC50 (119.32 ?g/mL and LC90, 213.84 ?g/mL) and C. quinquefasciatus (LC50, 130.30 ?g/mL and LC90, 228.20 ?g/mL). Synthesized AgNPs against the vector mosquitoes of A. stephensi, A. aegypti, and C. quinquefasciatus had the following LC50 and LC90 values: A. stephensi had LC50 and LC90 values of 21.92, and 41.07 ?g/mL; A. aegypti had LC50 and LC90 values of 23.96, and 44.05 ?g/mL; C. quinquefasciatus had LC50 and LC90 values of 26.13 and 47.52 ?g/mL. These results suggest that the use of S. acuta synthesized silver nanoparticles can be a rapid, environmentally safer biopesticide which can form a novel approach to develop effective biocides for controlling the target vector mosquitoes. This is the first report on the mosquito larvicidal activity of the plant aqueous extract and synthesized nanoparticles. PMID:24005479

Veerakumar, Kaliyan; Govindarajan, Marimuthu; Rajeswary, Mohan

2013-12-01

332

Natural odor ligands for olfactory receptor neurons of the female mosquito Aedes aegypti: use of gas chromatography-linked single sensillum recordings.  

PubMed

Female Aedes aegypti are vectors of dengue and yellow fever. Odor volatiles are the predominant cues that drive the host-seeking behavior of Ae. aegypti. Odorant molecules are detected and discriminated by olfactory receptor neurons (ORNs) housed in sensory hairs, sensilla, located on the antennae and maxillary palps. In a previous study, we used odor volatiles that are behaviorally and/or electrophysiologically active for Ae. aegypti and other mosquito species to show that antennal ORNs of female Ae. aegypti are divided into functionally different classes. In the present study, we have, for the first time, conducted gas chromatography-coupled single sensillum recordings (GC-SSR) from antennal trichoid and intermediate sensilla of female Ae. aegypti in order to screen for additional putative host attractants and repellents. We used headspace collections from biologically relevant sources, such as different human body parts (including feet, trunk regions and armpit), as well as a plant species used as a mosquito repellent, Nepeta faassenii. We found that a number of ORN types strongly responded to one or more of the biological extracts. GC-SSR recordings revealed several active components, which were subsequently identified through GC-linked mass spectrometry (GC-MS). Electrophysiologically active volatiles from human skin included heptanal, octanal, nonanal and decanal. PMID:18775939

Ghaninia, Majid; Larsson, Mattias; Hansson, Bill S; Ignell, Rickard

2008-09-01

333

Household survey of container-breeding mosquitoes and climatic factors influencing the prevalence of Aedes aegypti (Diptera: Culicidae) in Makkah City, Saudi Arabia  

PubMed Central

Objective To investigate the prevalence of container breeding mosquitoes with emphasis on the seasonality and larval habitats of Aedes aegypti (Ae. aegypti) in Makkah City, adjoining an environmental monitoring and dengue incidence. Methods Monthly visits were performed between April 2008 and March 2009 to randomly selected houses. During each visit, mosquito larvae were collected from indoors and outdoors containers by either dipping or pipetting. Mosquitoes were morphologically identified. Data on temperature, relative humidity, rain/precipitations during the survey period was retrieved from governmental sources and analyzed. Results The city was warmer in dry season (DS) than wet season (WS). No rain occurred at all during DS and even precipitations did fall, wetting events were much greater during WS. Larval survey revealed the co-breeding of Aedes, Culex and Anopheles in a variety of artificial containers in and around homes. 32?109 larvae representing 1st , 2nd, 3rd, and 4th stages were collected from 22?618 container habitats. Culicines was far the commonest and Aedes genus was as numerous as the Culex population. Ae. aegypti larval abundance exhibited marked temporal variations, overall, being usually more abundant during WS. Ten types of artificial containers were found with developing larvae. 70% of these habitats were located indoors. 71.42% of indoor containers were permanent and 28.58% was semi-permanent during WS. Cement tanks was the only container type permanent during DS. Ae. aegypti larval indices (CI, HI, BI) recorded were greater during WS. Conclusions Taken together, these results indicate a high risk of dengue transmission in the holy city. PMID:23569860

Aziz, Al Thabiany; Dieng, Hamady; Ahmad, Abu Hassan; Mahyoub, Jazem A; Turkistani, Abdulhafis M; Mesed, Hatabbi; Koshike, Salah; Satho, Tomomitsu; Salmah, MR Che; Ahmad, Hamdan; Zuharah, Wan Fatma; Ramli, Ahmad Saad; Miake, Fumio

2012-01-01

334

Longevity of Aedes aegypti (Diptera: Culicidae) compared in cages and field under ambient conditions in rural Thailand.  

PubMed

Aedes aegypti (L.) were exposed to all of the physiological stresses of a natural environment, without mortality from predation or from the defensive behavior of bitten hosts. Each replicate consisted of four cages containing 50 male and 50 female, locally reared Ae. aegypti. The cages were placed in the bedroom and kitchen of a typical Thai house in the village of Hua Samrong, Chachoengsao Province. Replicates were repeated five times between October 1991 and June 1992. Mosquitoes had constant access to sugar and were offered blood meals every day. The number of dead mosquitoes and eggs were recorded daily for 30 days. Indoor maximum temperatures were high throughout the year, ranging from a mean of 32.8 degrees C in October/November to 37.6 degrees C in March-April, with an absolute maximum of 41 degrees C. Survival in cages was related to temperature, with the force of mortality lowest in November-December (0.002) and highest in May-June (0.043). The negative slope of cohort survival was also greatest in the warmest months. Egg laying rate was lower in the cooler months (minimum 16.4 eggs/female/day in November-December), but did not vary greatly in absolute value (maximum 22.7 eggs/female/day in March-April). Statistically, survival of females in cages was much greater than survival calculated from mark-release-recapture studies conducted by other authors in Hua Samrong. The difference in survival for mosquitoes released in the field and those confined to cages suggests that predation or defensive behavior may be important in regulating adult populations of this vector. PMID:17120964

Strickman, Daniel

2006-05-01

335

Ecotoxicity and environmental risk assessment of larvicides used in the control of Aedes aegypti to Daphnia magna (Crustacea, Cladocera).  

PubMed

Dengue transmitted by mosquitoes of the genus Aedes, species aegypti, is a major public health concern in Brazil. The chemical control of the mosquito larvae has been performed with the larvicide temephos since 1967. However, vector resistance was reported to temephos in several Brazilian states, and the Ministry of Health ordered the replacement of this larvicide by diflubenzuron (DFB), an inhibitor of chitin synthesis. Both insecticides are diluted in water with larvae and are able to reach aquatic environments in which they subsequently adversely damage nontarget organisms. The aims of this study were to (1) determine the acute toxicity (EC50) and environmental risk (RQ) of DFB and temephos to the microcrustacean Daphnia magna, and (2) evaluate the chronic toxicity (no-observed-effect concentration [NOEC] and lowest-observed-effect concentration [LOEC]) of these larvicides to D. magna. The experiments were performed according to a completely randomized design. The estimated 48-h EC50 of temephos was 0.15 ?g/L (lower limit = 0.1 and upper limit = 0.2 ?g/L) and the 48-h EC50 of DFB was 0.06 ?g/L (lower limit = 0.03 and upper limit = 0.1 ?g/L). RQ values were 4.166.7 to DFB and 6.666.6 to temephos. NOEC and LOEC values were respectively 2.5 and 5 ng/L for DFB, and respectively 6.2 and 12.5 ng/L for temephos. Thus, temephos and DFB are classified as highly toxic to Daphnia magna and pose a high environmental risk to this species. Mortality of D. magna was observed at concentrations lower than those used in the field to control A. aegypti larvae. PMID:24555645

Abe, Flavia Renata; Coleone, Ana Carla; Machado, Angela Aparecida; Gonçalves Machado-Neto, Joaquim

2014-01-01

336

Mechanisms of pyrethroid resistance in the dengue mosquito vector, Aedes aegypti: target site insensitivity, penetration, and metabolism.  

PubMed

Aedes aegypti is the major vector of yellow and dengue fevers. After 10 generations of adult selection, an A. aegypti strain (SP) developed 1650-fold resistance to permethrin, which is one of the most widely used pyrethroid insecticides for mosquito control. SP larvae also developed 8790-fold resistance following selection of the adults. Prior to the selections, the frequencies of V1016G and F1534C mutations in domains II and III, respectively, of voltage-sensitive sodium channel (Vssc, the target site of pyrethroid insecticide) were 0.44 and 0.56, respectively. In contrast, only G1016 alleles were present after two permethrin selections, indicating that G1016 can more contribute to the insensitivity of Vssc than C1534. In vivo metabolism studies showed that the SP strain excreted permethrin metabolites more rapidly than a susceptible SMK strain. Pretreatment with piperonyl butoxide caused strong inhibition of excretion of permethrin metabolites, suggesting that cytochrome P450 monooxygenases (P450s) play an important role in resistance development. In vitro metabolism studies also indicated an association of P450s with resistance. Microarray analysis showed that multiple P450 genes were over expressed during the larval and adult stages in the SP strain. Following quantitative real time PCR, we focused on two P450 isoforms, CYP9M6 and CYP6BB2. Transcription levels of these P450s were well correlated with the rate of permethrin excretion and they were certainly capable of detoxifying permethrin to 4'-HO-permethrin. Over expression of CYP9M6 was partially due to gene amplification. There was no significant difference in the rate of permethrin reduction from cuticle between SP and SMK strains. PMID:24945250

Kasai, Shinji; Komagata, Osamu; Itokawa, Kentaro; Shono, Toshio; Ng, Lee Ching; Kobayashi, Mutsuo; Tomita, Takashi

2014-06-01

337

In vitro activation and enzyme kinetic analysis of recombinant midgut serine proteases from the Dengue vector mosquito Aedes aegypti  

PubMed Central

Background The major Dengue virus vector Aedes aegypti requires nutrients obtained from blood meal proteins to complete the gonotrophic cycle. Although bioinformatic analyses of Ae. aegypti midgut serine proteases have provided evolutionary insights, very little is known about the biochemical activity of these digestive enzymes. Results We used peptide specific antibodies to show that midgut serine proteases are expressed as zymogen precursors, which are cleaved to the mature form after blood feeding. Since midgut protein levels are insufficient to purify active proteases directly from blood fed mosquitoes, we engineered recombinant proteins encoding a heterologous enterokinase cleavage site to permit generation of the bona fide mature form of four midgut serine proteases (AaET, AaLT, AaSPVI, AaSPVII) for enzyme kinetic analysis. Cleavage of the chromogenic trypsin substrate BApNA showed that AaET has a catalytic efficiency (kcat/KM) that is ~30 times higher than bovine trypsin, and ~2-3 times higher than AaSPVI and AaSPVII, however, AaLT does not cleave BApNA. To measure the enzyme activities of the mosquito midgut proteases using natural substrates, we developed a quantitative cleavage assay based on cleavage of albumin and hemoglobin proteins. These studies revealed that the recombinant AaLT enzyme was indeed catalytically active, and cleaved albumin and hemoglobin with equivalent efficiency to that of AaET, AaSPVI, and AaSPVII. Structural modeling of the AaLT and AaSPVI mature forms indicated that AaLT is most similar to serine collagenases, whereas AaSPVI appears to be a classic trypsin. Conclusions These data show that in vitro activation of recombinant serine proteases containing a heterologous enterokinase cleavage site can be used to investigate enzyme kinetics and substrate cleavage properties of biologically important mosquito proteases. PMID:21827688

2011-01-01

338

Mechanisms of Pyrethroid Resistance in the Dengue Mosquito Vector, Aedes aegypti: Target Site Insensitivity, Penetration, and Metabolism  

PubMed Central

Aedes aegypti is the major vector of yellow and dengue fevers. After 10 generations of adult selection, an A. aegypti strain (SP) developed 1650-fold resistance to permethrin, which is one of the most widely used pyrethroid insecticides for mosquito control. SP larvae also developed 8790-fold resistance following selection of the adults. Prior to the selections, the frequencies of V1016G and F1534C mutations in domains II and III, respectively, of voltage-sensitive sodium channel (Vssc, the target site of pyrethroid insecticide) were 0.44 and 0.56, respectively. In contrast, only G1016 alleles were present after two permethrin selections, indicating that G1016 can more contribute to the insensitivity of Vssc than C1534. In vivo metabolism studies showed that the SP strain excreted permethrin metabolites more rapidly than a susceptible SMK strain. Pretreatment with piperonyl butoxide caused strong inhibition of excretion of permethrin metabolites, suggesting that cytochrome P450 monooxygenases (P450s) play an important role in resistance development. In vitro metabolism studies also indicated an association of P450s with resistance. Microarray analysis showed that multiple P450 genes were over expressed during the larval and adult stages in the SP strain. Following quantitative real time PCR, we focused on two P450 isoforms, CYP9M6 and CYP6BB2. Transcription levels of these P450s were well correlated with the rate of permethrin excretion and they were certainly capable of detoxifying permethrin to 4?-HO-permethrin. Over expression of CYP9M6 was partially due to gene amplification. There was no significant difference in the rate of permethrin reduction from cuticle between SP and SMK strains. PMID:24945250

Kasai, Shinji; Komagata, Osamu; Itokawa, Kentaro; Shono, Toshio; Ng, Lee Ching; Kobayashi, Mutsuo; Tomita, Takashi

2014-01-01

339

Development and evaluation of a novel contamination device that targets multiple life-stages of Aedes aegypti  

PubMed Central

Background The increasing global threat of Dengue demands new and easily applicable vector control methods. Ovitraps provide a low-tech and inexpensive means to combat Dengue vectors. Here we describe the development and optimization process of a novel contamination device that targets multiple life-stages of the Aedes aegypti mosquito. Special focus is directed to the diverse array of control agents deployed in this trap, covering adulticidal, larvicidal and autodissemination impacts. Methods Different trap prototypes and their parts are described, including a floater to contaminate alighting gravid mosquitoes. The attractiveness of the trap, different odor lures and floater design were studied using fluorescent powder adhering to mosquito legs and via choice tests. We demonstrate the mosquitocidal impacts of the control agents: a combination of the larvicide pyriproxyfen and the adulticidal fungus Beauveria bassiana. The impact of pyriproxyfen was determined in free-flight dissemination experiments. The effect on larval development inside the trap and in surrounding breeding sites was measured, as well as survival impacts on recaptured adults. Results The developmental process resulted in a design that consists of a black 3 Liter water-filled container with a ring-shaped floater supporting vertically placed gauze dusted with the control agents. On average, 90% of the mosquitoes in the fluorescence experiments made contact with the gauze on the floater. Studies on attractants indicated that a yeast-containing tablet was the most attractive odor lure. Furthermore, the fungus Beauveria bassiana was able to significantly increase mortality of the free-flying adults compared to controls. Dissemination of pyriproxyfen led to >90% larval mortality in alternative breeding sites and 100% larval mortality in the trap itself, against a control mortality of around 5%. Conclusion This ovitrap is a promising new tool in the battle against Dengue. It has proven to be attractive to Aedes aegypti mosquitoes and effective in contaminating these with Beauveria bassiana. Furthermore, we show that the larvicide pyriproxyfen is successfully disseminated to breeding sites close to the trap. Its low production and operating costs enable large scale deployment in Dengue-affected locations. PMID:24766772

2014-01-01

340

Preliminary evaluation on the efficiency of the kit Platelia Dengue NS1 Ag-ELISA to detect dengue virus in dried Aedes aegypti: a potential tool to improve dengue surveillance  

PubMed Central

Background Surveillance is a critical component of any dengue prevention and control programme. Herein, we investigate the efficiency of the commercial kit Platelia Dengue NS1 Ag-ELISA to detect dengue virus (DENV) antigens in Aedes aegypti mosquitoes infected under laboratory conditions. Methods Under insectary conditions, four to five day-old mosquitoes were orally challenged with DENV-2 titer of 3.6 x 105 PFU equivalent/ml, incubated for 14 days and then killed. At ten time-points following mosquito death (0, 6, 12, 24, 72, 96, 120, 144 and 168 h), i.e., during a one-week period, dried mosquitoes were comparatively tested for the detection of the NS1 antigen with other methods of detection, such as qRT-PCR and virus isolation in C6/36 cells. Results We first observed that the NS1 antigen was more effective in detecting DENV-2 in Ae. aegypti between 12 and 72 h after mosquito death when compared with qRT-PCR. A second round involved comparing the sensitivity of detection of the NS1 antigen and virus isolation in C6/36 cells. The NS1 antigen was also more effective than virus isolation, detecting DENV-2 at all time-points, i.e., up to 168 h after mosquito death. Meanwhile, virus isolation was successful up to 96 h after Ae. aegypti death, but the number of positive samples per time period presented a tendency to decline progressively over time. From the 43 samples positive by the virus isolation technique, 38 (88.4%) were also positive by the NS1 test. Conclusion Taken together, these results are the first to indicate that the NS1 antigen might be an interesting complementary tool to improve dengue surveillance through DENV detection in dried Ae. aegypti females. PMID:24690324

2014-01-01

341

Validation of models to estimate the fumigant and larvicidal activity of Eucalyptus essential oils against Aedes aegypti (Diptera: Culicidae).  

PubMed

The aim of this work is to validate the pre-existing models that relate the larvicidal and adulticidal activities of the Eucalyptus essential oils on Aedes aegypti. Previous works at our laboratory described that the larvicidal activity of Eucalyptus essential oils can be estimated from the relative concentration of two main components (p-cymene and 1,8-cineole) and that the adulticidal effectiveness can be explained, to a great extent, by the presence of large amounts of the component 1,8-cineole in it. In general, the results show that the higher adulticidal effect of essential oils the lower their larvicidal activity. Fresh leaves was harvested and distilled. Once the essential oil was obtained, the chemical composition was analysed, evaluating the biological activity of 15 species of the genus Eucalyptus (Eucalyptus badjensis Beuzev and Welch, Eucalyptus badjensis × nitens, Eucalyptus benthamii var Benthamii Maiden and Cambage, Eucalyptus benthamii var dorrigoensis Maiden and Cambage, Eucalyptus botryoides Smith, Eucalyptus dalrympleana Maiden, Eucalyptus fastigata Deane and Maiden, Eucalyptus nobilis L.A.S. Johnson and K.D.Hill, Eucalyptus polybractea R. Baker, Eucalyptus radiata ssp radiata Sieber ex Spreng, Eucalyptus resinifera Smith, Eucalyptus robertsonii Blakely, Eucalyptus robusta Smith, Eucalyptus rubida Deane and Maiden, Eucalyptus smithii R. Baker). Essential oils of these plant species were used for the validation of equations from preexistent models, in which observed and estimated values of the biological activity were compared. The regression analysis showed a strong validation of the models, re-stating the trends previously observed. The models were expressed as follows: A, fumigant activity [KT(50(min)) = 10.65-0.076 × 1,8-cineole (%)](p < 0.01; F, 397; R (2), 0.79); B, larval mortality (%)((40 ppm)) = 103.85 + 0.482 × p-cymene (%) - 0.363 × ?-pinene (%) - 1.07 × 1,8-cineole (%) (p < 0.01; F, 300; R (2), 0.90). These results confirmed the importance of the mayor components in the biological activity of Eucalyptus essential oils on A. aegypti. However, it is worth mentioning that two or three species differ in the data estimated by the models, and these biological activity results coincide with the presence of minor differential components in the essential oils. According to what was previously mentioned, it can be inferred that the model is able to estimate very closely the biological activity of essential oils of Eucalyptus on A. aegypti. PMID:22042502

Lucia, Alejandro; Juan, Laura W; Zerba, Eduardo N; Harrand, Leonel; Marcó, Martín; Masuh, Hector M

2012-05-01

342

Adulticidal and repellent properties of Cassia tora Linn. (Family: Caesalpinaceae) against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi.  

PubMed

Mosquitoes have developed resistance to various synthetic insecticides, making its control increasingly difficult. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. The adulticidal and repellent activities of crude hexane, chloroform, benzene, acetone, and methanol extracts of the leaf of Cassia tora were assayed for their toxicity against three important vector mosquitoes, viz., Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi. The adult mortality was observed after 24 h of exposure. All extracts showed moderate adulticidal effects; however, the highest adult mortality observed was found in methanol extract. The LC(50) and LC(90) values of C. tora leaf extracts against adulticidal activity of (hexane, chloroform benzene, acetone, and methanol) C. quinquefasciatus, A. aegypti, and A. stephensi were the following: C. quinquefasciatus LC(50) values were 338.81, 315.73, 296.13, 279.23, and 261.03 ppm and LC(90) values were 575.77, 539.31, 513.99, 497.06, and 476.03 ppm; A. aegypti LC(50) values were 329.82, 307.31, 287.15, 269.57, and 252.03 ppm and LC(90) values were 563.24, 528.33, 496.92, 477.61, and 448.05 ppm; and A. stephensi LC(50) values were 317.28, 300.30, 277.51, 263.35, and 251.43 ppm and LC(90) values were 538.22, 512.90, 483.78, 461.08, and 430.70 ppm, respectively. The results of the repellent activity of hexane, chloroform, benzene, acetone, and methanol extracts of C. tora plant at three different concentrations of 1.0, 2.5, and 5.0 mg/cm(2) were applied on skin of forearm in man and exposed against adult female mosquitoes. In this observation, this plant crude extracts gave protection against mosquito bites without any allergic reaction to the test person, and also, the repellent activity is dependent on the strength of the plant extracts. These results suggest that the leaf solvent plant extracts have the potential to be used as an ideal eco-friendly approach for the control of mosquitoes. This is the first report on mosquito adulticidal and repellent activities of the reported C. tora against mosquito vectors from Southern India. PMID:22821231

Amerasan, Duraisamy; Murugan, Kadarkarai; Kovendan, Kalimuthu; Mahesh Kumar, Palanisamy; Panneerselvam, Chellasamy; Subramaniam, Jayapal; John William, Samuel; Hwang, Jiang-Shiou

2012-11-01

343

A lethal ovitrap-based mass trapping scheme for dengue control in Australia: II. Impact on populations of the mosquito Aedes aegypti.  

PubMed

In Cairns, Australia, the impacts on Aedes aegypti L. (Diptera: Culicidae) populations of two types of 'lure & kill' (L&K) lethal ovitraps (LOs), the standard lethal ovitrap (SLO) and the biodegradable lethal ovitrap (BLO) were measured during three mass-trapping interventions. To assess the efficacy of the SLO, two interventions (one dry season and one wet season) were conducted in three discrete areas, each lasting 4 weeks, with the following treatments: (i) SLOs (>200 traps, approximately 4/premise), BG-sentinel traps (BGSs; approximately 15, 1/premise) and larval control (container reduction and methoprene treatment) and (ii) larval control alone, and (iii) untreated control. Female Ae. aegypti populations were monitored for 4 weeks pre- and post-treatment in all three areas using BGSs and sticky ovitraps (SOs) or non-lethal regular ovitraps (ROs). In the dry season, 206 SLOs and 15 BGSs set at 54 and 15 houses, respectively, caught and killed an estimated 419 and 73 female Ae. aegypti, respectively. No significant decrease in collection size of female Ae. aegypti could be attributed to the treatments. In the wet season, 243 SLOs and 15 BGSs killed approximately 993 and 119 female Ae. aegypti, respectively. The mean number of female Ae. aegypti collected after 4 weeks with SOs and BGSs was significantly less than the control (LSD post-hoc test). The third mass-trapping intervention was conducted using the BLO during the wet season in Cairns. For this trial, three treatment areas were each provided with BLOs (>500, approximately 4/premise) plus larval control, and an untreated control area was designated. Adult female Ae. aegypti were collected for 4 weeks pre- and post-treatment using 15 BGSs and 20 SOs. During this period, 53.2% of BLOs contained a total of 6654 Ae. aegypti eggs. Over the intervention period, collections of Ae. aegypti in the treatment areas were significantly less than in the control area for BGSs but not SOs. An influx of relatively large numbers of young females may have confounded the measurement of changes in populations of older females in these studies. This is an important issue, with implications for assessing delayed action control measures, such as LOs and parasites/pathogens that aim to change mosquito age structure. Finally, the high public acceptability of SLOs and BLOs, coupled with significant impacts on female Ae. aegypti populations in two of the three interventions reported here, suggest that mass trapping with SLOs and BLOs can be an effective component of a dengue control strategy. PMID:19941596

Rapley, L P; Johnson, P H; Williams, C R; Silcock, R M; Larkman, M; Long, S A; Russell, R C; Ritchie, S A

2009-12-01

344

Geometric Morphometrics of Nine Field Isolates of Aedes aegypti with Different Resistance Levels to Lambda-Cyhalothrin and Relative Fitness of One Artificially Selected for Resistance  

PubMed Central

Aedes aegypti, a mosquito closely associated with humans, is the principal vector of dengue virus which currently infects about 400 million people worldwide. Because there is no way to prevent infection, public health policies focus on vector control; but insecticide-resistance threatens them. However, most insecticide-resistant mosquito populations exhibit fitness costs in absence of insecticides, although these costs vary. Research on components of fitness that vary with insecticide-resistance can help to develop policies for effective integrated management and control. We investigated the relationships in wing size, wing shape, and natural resistance levels to lambda-cyhalothrin of nine field isolates. Also we chose one of these isolates to select in lab for resistance to the insecticide. The main life-traits parameters were assessed to investigate the possible fitness cost and its association with wing size and shape. We found that wing shape, more than wing size, was strongly correlated with resistance levels to lambda-cyhalothrin in field isolates, but founder effects of culture in the laboratory seem to change wing shape (and also wing size) more easily than artificial selection for resistance to that insecticide. Moreover, significant fitness costs were observed in response to insecticide-resistance as proved by the diminished fecundity and survival of females in the selected line and the reversion to susceptibility in 20 generations of the non-selected line. As a practical consequence, we think, mosquito control programs could benefit from this knowledge in implementing efficient strategies to prevent the evolution of resistance. In particular, the knowledge of reversion to susceptibility is important because it can help in planning better strategies of insecticide use to keep useful the few insecticide-molecules currently available. PMID:24801598

Jaramillo-O., Nicolas; Fonseca-Gonzalez, Idalyd; Chaverra-Rodriguez, Duverney

2014-01-01

345

Geometric morphometrics of nine field isolates of Aedes aegypti with different resistance levels to lambda-cyhalothrin and relative fitness of one artificially selected for resistance.  

PubMed

Aedes aegypti, a mosquito closely associated with humans, is the principal vector of dengue virus which currently infects about 400 million people worldwide. Because there is no way to prevent infection, public health policies focus on vector control; but insecticide-resistance threatens them. However, most insecticide-resistant mosquito populations exhibit fitness costs in absence of insecticides, although these costs vary. Research on components of fitness that vary with insecticide-resistance can help to develop policies for effective integrated management and control. We investigated the relationships in wing size, wing shape, and natural resistance levels to lambda-cyhalothrin of nine field isolates. Also we chose one of these isolates to select in lab for resistance to the insecticide. The main life-traits parameters were assessed to investigate the possible fitness cost and its association with wing size and shape. We found that wing shape, more than wing size, was strongly correlated with resistance levels to lambda-cyhalothrin in field isolates, but founder effects of culture in the laboratory seem to change wing shape (and also wing size) more easily than artificial selection for resistance to that insecticide. Moreover, significant fitness costs were observed in response to insecticide-resistance as proved by the diminished fecundity and survival of females in the selected line and the reversion to susceptibility in 20 generations of the non-selected line. As a practical consequence, we think, mosquito control programs could benefit from this knowledge in implementing efficient strategies to prevent the evolution of resistance. In particular, the knowledge of reversion to susceptibility is important because it can help in planning better strategies of insecticide use to keep useful the few insecticide-molecules currently available. PMID:24801598

Jaramillo-O, Nicolás; Fonseca-González, Idalyd; Chaverra-Rodríguez, Duverney

2014-01-01

346

Laboratory and field evaluation of the effects of the neonicotinoid imidacloprid on the oviposition response of Aedes (Stegomyia) aegypti Linnaeus (Diptera: Culicidae).  

PubMed

In this paper, we assessed the suitability of using the neonicotinoid imidacloprid with standard ovitraps by evaluating the ovicidal properties of imidacloprid and its influence on the oviposition response of gravid females of Aedes (Stegomyia) aegypti Linnaeus (Diptera: Culicidae). First, we calculated the imidacloprid lethal dose 99 (LD(99)) by exposing third instar larvae of the target species to different concentrations of the insecticide. Next, Ae. aegypti eggs were exposed to the imidacloprid LD(99) for 24 h and hatching inhibition was recorded. Finally, we investigated any potential repellent effect of the imidacloprid solution on the oviposition response of gravid Aedes females in field and laboratory conditions. The LD(99) obtained from larvae tests proved to be sufficient to keep any exposed eggs from hatching. No repellent effect was observed; females laid as many eggs in imidacloprid-treated ovitraps as in traps containing either clean water or temephos-treated water in both field and laboratory conditions. Our results indicate that imidacloprid is a suitable insecticide for treating ovitraps against Ae. aegypti. PMID:22241123

Antonio-Arreola, Gloria Elsa; López-Bello, Roger; Romero-Moreno, Daenna Kaori; Sánchez, Daniel

2011-12-01

347

Proteome Analysis of Cry4Ba Toxin-Interacting Aedes aegypti Lipid Rafts using geLC-MS/MS  

PubMed Central

Lipid rafts are microdomains in the plasma membrane of eukaryotic cells. Among their many functions, lipid rafts are involved in cell toxicity caused by pore forming bacterial toxins including Bacillus thuringiensis (Bt) Cry toxins. We isolated lipid rafts from brush border membrane vesicles (BBMV) of Aedes aegypti larvae as a detergent resistant membrane (DRM) fraction on density gradients. Cholesterol, aminopeptidase (APN), alkaline phosphatase (ALP) and the raft marker flotillin were preferentially partitioned into the lipid raft fraction. When mosquitocidal Cry4Ba toxin was pre-incubated with BBMV, Cry4Ba localized to lipid rafts. A proteomic approach based on one dimensional gel electrophoresis, in-gel trypsin digestion, followed by liquid chromatography-mass spectrometry (geLC-MS/MS) identified a total of 386 proteins. Of which many are typical lipid raft marker proteins including flotillins and glycosylphosphatidylinositol (GPI)-anchored proteins. Identified raft proteins were annotated in silico for functional and physicochemical characteristics. Parameters such as distribution of isoelectric point, molecular mass, and predicted post-translational modifications relevant to lipid raft proteins (GPI anchorage and myristoylation or palmitoylation) were analyzed for identified proteins in the DRM fraction. From a functional point of view, this study identified proteins implicated in Cry toxin interactions as well as membrane-associated proteins expressed in the mosquito midgut that have potential relevance to mosquito biology and vector management. PMID:23153095

Bayyareddy, Krishnareddy; Zhu, Xiang; Orlando, Ron; Adang, Michael J.

2012-01-01

348

BIGLUTAMINYL-BILIVERDIN IX ALPHA AS A HEME DEGRADATION PRODUCT IN THE DENGUE FEVER INSECT-VECTOR Aedes aegypti  

PubMed Central

Hemoglobin digestion in the midgut of hematophagous animals results in the release of its prosthetic group, heme, which is a pro-oxidant molecule. Heme enzymatic degradation is a protective mechanism that has been described in several organisms, including plants, bacteria, and mammals. This reaction is catalyzed by heme oxygenase and results in formation of carbon monoxide, ferrous ion, and biliverdin IX?. During digestion, a large amount of a green pigment is produced and secreted into the intestinal lumen of A. aegypti adult females. In the case of another blood-sucking insect, the kissing-bug Rhodnius prolixus, we have recently shown that heme degradation involves a complex pathway that generates dicysteinyl-biliverdin IX gamma. The light absorption spectrum of the Aedes purified pigment was similar to biliverdin, but its mobility on a reverse-phase chromatography column suggested a compound less hydrophobic than biliverdin IX?. Structural characterization by ESI-MS revealed that the mosquito pigment is the ? isomer of biliverdin bound to two glutamine residues by an amide bond. This biglutaminyl-biliverdin is formed by oxidative cleavage of the heme porphyrin ring followed by two subsequent additions of glutamine residues to the biliverdin IX?. The role of this pathway in the adaptation of this insect vector to a blood-feeding habit is discussed. PMID:17508725

Pereira, Luiza O. R.; Oliveira, Pedro L.; Almeida, Igor C.; Paiva-Silva, Gabriela O.

2008-01-01

349

Knockdown and repellent effect of permethrin-impregnated army uniform cloth against Aedes aegypti after different cycles of washings.  

PubMed

Personnel protection is one of the methods for protection from bites of mosquitoes and other arthropod vectors transmitting many dreadful diseases. Insect repellents and other plant products are normally used to ward off mosquitoes. Application of synthetic pyrethroid permethrin on cloth is adopted for repelling arthropod vectors in many countries for military and civil purposes. In the present study, attempt has been made to impregnate permethrin in the army uniform cloth and to evaluate for its knockdown and repellency against unfed female Aedes aegypti mosquitoes in laboratory condition. WHO protocols were adopted for impregnation of permethrin on cloth and evaluation for its knockdown and repellency after different cycles of washing. Results showed that 93.33% of mosquitoes were knocked down within 1 h after the first washing while its efficacy reduced gradually till the fifty-fifth washing. Landing of mosquitoes on the permethrin-treated cloth was found to increase with respect to number of washings as compared to the untreated cloth. Within 24 h, 100% mortality of all the mosquitoes exposed to permethrin-impregnated cloth was observed. SEM-EDX studies on the texture of untreated cloth and permethrin-treated cloth after different cycles of washing also revealed presence of permethrin on treated cloth. PMID:24595642

Sukumaran, D; Sharma, Ajay Kumar; Wasu, Yogesh H; Pandey, Pratibha; Tyagi, Varun

2014-05-01

350

Design, synthesis, acetylcholinesterase inhibition and larvicidal activity of girgensohnine analogs on Aedes aegypti, vector of dengue fever.  

PubMed

Girgensohnine alkaloid was used as a natural model in the design and generation of new alkaloid-like ?-aminonitrile series that was completed by the use of SSA-catalyzed Strecker reaction between commercial and inexpensive substituted benzaldehydes, piperidine (pyrrolidine, morpholine and N-methylpiperazine) and acetone cyanohydrin. Calculated ADMETox parameters of the designed analogs revealed their good pharmacokinetic profiles indicating lipophilic characteristics. In vitro AChE enzyme test showed that obtained ?-aminonitriles could be considered as AChEIs with micromolar IC50 values ranging from 42.0 to 478.0 ?M (10.3-124.0 ?g/mL). Among this series, the best AChE inhibitor was the pyrrolidine ?-aminonitrile 3 (IC50 = 42 ?M), followed by the piperidine ?-aminonitriles 2 and 6 (IC50 = 45 ?M and IC50 = 51 ?M, respectively), and the compound 7 (IC50 = 51 ?M). In vivo insecticidal activity of more active AChEIs against Aedes aegypti larvae was also performed showing a good larvicidal activity at concentrations less than 140 ppm, highlighting products 2 and 7 that could serve as lead compounds to develop new potent and selective insecticides. PMID:24704612

Carreño Otero, Aurora L; Vargas Méndez, Leonor Y; Duque L, Jonny E; Kouznetsov, Vladimir V

2014-05-01

351

Bioassay-guided investigation of two Monarda essential oils as repellents of yellow fever mosquito Aedes aegypti.  

PubMed

As part of an ongoing research program to identify active mosquito repellents, Monarda bradburiana Beck and Monarda fistulosa L. essential oils showed good repellent activity with minimum effective dosages (MED) of 0.055 ± 0.036 and 0.078 ± 0.027 mg/cm(2), respectively, compared to reference standard N,N-diethyl-3-methylbenzamide (DEET) (0.039 ± 0.014 mg/cm(2)). Systematic bioassay-guided fractionation of essential oils of both Monarda species was performed to identify the active repellent compounds, and isolated pure compounds were individually tested for repellency. Of the isolated compounds, carvacrol, thymol, eugenol, and carvacrol methyl ether were found to be the repellent compounds with MEDs in the range of 0.013-0.063 mg/cm(2). Active repellent compounds were also tested for larvicidal activity against 1-day-old Aedes aegypti larvae. Thymol was the best larvicide among the tested individual compounds (LD50 of 13.9 ppm). None of the individual compounds showed cytotoxicity against mammalian cells; however, the essential oils were toxic to all cell lines. PMID:23919579

Tabanca, Nurhayat; Bernier, Ulrich R; Ali, Abbas; Wang, Mei; Demirci, Betul; Blythe, Eugene K; Khan, Shabana I; Baser, K Husnu Can; Khan, Ikhlas A

2013-09-11

352

Effects of grapefruit (Citrus paradisi MACF) (Rutaceae) peel oil against developmental stages of Aedes aegypti (Diptera: Culicidae).  

PubMed

Laboratory bioassay of the essential oil extracted from the grapefruit (Citrus paradisi) peel by steam distillation was carried out against the developmental stages of the yellow fever vector Aedes aegypti to evaluate its toxicity, and ovicidal and larvicidal potency. Volatile oil components isolated and characterized by coupled gas chromatography/mass spectrometry included varying levels of monoterpene aldehydes, alcohols, and esters. Test results of the essential oil showed that egg hatching was completely inhibited at 400 ppm, while further development of 1st to 2nd larval stage was inhibited at 100 ppm. Regression analysis results also indicated that the peel essential oil significantly (p<0.01) reduced the viability of the test eggs and inhibited the development of 1st larval stage to 2nd larval instar. The LC50 and LC90 values obtained for 2nd instars (180.460, 334.629 ppm, respectively); and for 4th instars (210.937, 349.489 ppm, respectively) after 24-hour exposure were time but not dose dependent, as each LC value was a product of an inverse relationship between the oil concentration and exposure time. The results indicated that the peel oil could be a potent persistent larvicide. PMID:24450234

Ivoke, Njoku; Ogbonna, Priscilla C; Ekeh, Felicia N; Ezenwaji, Ngozi E; Atama, Chinedu I; Ejere, Vincent C; Onoja, Uwakwe S; Eyo, Joseph E

2013-11-01

353

Proteome analysis of Cry4Ba toxin-interacting Aedes aegypti lipid rafts using geLC-MS/MS.  

PubMed

Lipid rafts are microdomains in the plasma membrane of eukaryotic cells. Among their many functions, lipid rafts are involved in cell toxicity caused by pore forming bacterial toxins including Bacillus thuringiensis (Bt) Cry toxins. We isolated lipid rafts from brush border membrane vesicles (BBMV) of Aedes aegypti larvae as a detergent resistant membrane (DRM) fraction on density gradients. Cholesterol, aminopeptidase (APN), alkaline phosphatase (ALP) and the raft marker flotillin were preferentially partitioned into the lipid raft fraction. When mosquitocidal Cry4Ba toxin was preincubated with BBMV, Cry4Ba localized to lipid rafts. A proteomic approach based on one-dimensional gel electrophoresis, in-gel trypsin digestion, followed by liquid chromatography-mass spectrometry (geLC-MS/MS) identified a total of 386 proteins. Of which many are typical lipid raft marker proteins including flotillins and glycosylphosphatidylinositol (GPI)-anchored proteins. Identified raft proteins were annotated in silico for functional and physicochemical characteristics. Parameters such as distribution of isoelectric point, molecular mass, and predicted post-translational modifications relevant to lipid raft proteins (GPI anchorage and myristoylation or palmitoylation) were analyzed for identified proteins in the DRM fraction. From a functional point of view, this study identified proteins implicated in Cry toxin interactions as well as membrane-associated proteins expressed in the mosquito midgut that have potential relevance to mosquito biology and vector management. PMID:23153095

Bayyareddy, Krishnareddy; Zhu, Xiang; Orlando, Ron; Adang, Michael J

2012-12-01

354

Evaluation of repellent properties of volatile extracts from the Australian native plant Kunzea ambigua against Aedes aegypti (Diptera: Culcidae).  

PubMed

Kunzea ambigua (Smith) Druce (Myrtaceae) is an Australian native plant, commonly known as tick bush. The essential oil of the plant has been proposed as a potential mosquito repellent. Commercial K. ambigua oil was analyzed by gas chromatography-mass spectrometry (GC-MS) and its composition compared with that of oils from two individual K. ambigua plants and citronella oil. K. ambigua oils were studied for their repellency against Aedes aegypti L. Formulations of three different K. ambigua essential oils (30% vol:vol) were tested for repellency to mosquitoes using human volunteers. One oil was compared with citronella and N,N'-diethyl-3-methylbenzamide (deet) for repellency. Oil formulations were also tested for repellency with and without the addition of 5% vanillin. The formulation containing commercially produced K. ambigua oil had a mean complete protection time (CPT) of 49 +/- 24 (SD) min. All the K. ambigua formulations had comparable repellency to 40% citronella. However, the 60% citronella formulation showed higher repellency than the 40% K. ambigua formulation. The addition of 5% vanillin did not increase the repellency of K. ambigua oil. Both K. ambigua oil and citronella were significantly less repellent than deet. The K. ambigua essential oil formulations should not be advocated for use as repellents in regions prone to mosquito-borne disease. PMID:19960685

Thomas, J; Webb, C E; Narkowicz, C; Jacobson, G A; Peterson, G M; Davies, N W; Russell, R C

2009-11-01

355

Initial Assessment of the Acceptability of a Push-Pull Aedes aegypti Control Strategy in Iquitos, Peru and Kanchanaburi, Thailand  

PubMed Central

As part of a larger research program evaluating chemical threshold levels for a Push-Pull intervention to reduce man-vector (Aedes aegypti) contact, this qualitative study explored local perceptions and strategies associated with mosquito control within dengue-endemic communities in Peru and Thailand. Focus groups were used to provide preliminary information that would identify possible public acceptance issues to the Push-Pull strategy in each site. Nine focus group discussions (total of 102 individuals) conducted between September 2008 and March 2009 examined several themes: 1) current mosquito control practices; 2) perceptions of spatial repellency and contact irritancy versus killing mosquitoes; and 3) initial perceptions toward mosquito host-seeking traps. Results indicate participants use household-level strategies for insect control that reveal familiarity with the concept of spatial repellent and contact irritant actions of chemicals and that placing traps in the peridomestic environment to remove repelled mosquitoes was acceptable. Preliminary evidence suggests a Push-Pull strategy should be well accepted in these locations. These results will be beneficial for developing future large scale push-pull interventions and are currently being used to guide insecticide application strategies in (entomological) proof-of-concept studies using experimental huts. PMID:21292886

Paz-Soldan, Valerie A.; Plasai, Valaikanya; Morrison, Amy C.; Rios-Lopez, Esther J.; Guedez-Gonzales, Shirly; Grieco, John P.; Mundal, Kirk; Chareonviriyaphap, Theeraphap; Achee, Nicole L.

2011-01-01

356

Sustainability and cost of a community-based strategy against Aedes aegypti in northern and central Vietnam.  

PubMed

We previously reported a new community-based mosquito control that resulted in the elimination of Aedes aegypti in 40 of 46 communes in northern and central Vietnam. During 2007 and 2008, we revisited Nam Dinh and Khanh Hoa provinces in northern and central Vietnam, respectively, to evaluate whether or not these programs were still being maintained 7 years and 4.5 years after formal project activities had ceased, respectively. Using a previously published sustainability framework, we compared 13 criteria from Tho Nghiep commune in Nam Dinh where the local community had adopted our community-based project model using Mesocyclops from 2001. These data were compared against a formal project commune, Xuan Phong, where our successful intervention activities had ceased in 2000 and four communes operating under the National Dengue Control Program with data available. In Khanh Hoa province, we compared 2008 data at Ninh Xuan commune with data at project completion in 2003 and benchmarked these, where possible, against an untreated control commune, Ninh Binh, where few control activities had been undertaken. The three communes where the above community-based strategy had been adopted were rated as well-sustained with annual recurrent total costs (direct and indirect) of $0.28-0.89 international dollars per person. PMID:20439962

Kay, Brian H; Tuyet Hanh, Tran T; Le, Nguyen Hoang; Quy, Tran Minh; Nam, Vu Sinh; Hang, Phan V D; Yen, Nguyen Thi; Hill, Peter S; Vos, Theo; Ryan, Peter A

2010-05-01

357

A Secure Semi-Field System for the Study of Aedes aegypti  

Microsoft Academic Search

BackgroundNew contained semi-field cages are being developed and used to test novel vector control strategies of dengue and malaria vectors. We herein describe a new Quarantine Insectary Level-2 (QIC-2) laboratory and field cages (James Cook University Mosquito Research Facility Semi-Field System; MRF SFS) that are being used to measure the impact of the endosymbiont Wolbachia pipientis on populations of Aedes

Scott A. Ritchie; Petrina H. Johnson; Anthony J. Freeman; Robin G. Odell; Neal Graham; Paul A. DeJong; Graeme W. Standfield; Richard W. Sale; Scott L. ONeill

2011-01-01

358

Immunolocalization and in vivo Functional Analysis by RNAi of the Aedes Kinin Receptor in Female Mosquitoes of Aedes aegypti (L.) (Diptera, Culicidae)  

E-print Network

kinins are leucokinin-like neuropeptides released from neurosecretory cells in the brain and abdominal ganglia. They act by binding to the Aedes kinin receptor, a G proteincoupled receptor (GPCR). The Aedes kinin receptor has been cloned, sequenced...

Kersch, Cymon

2012-02-14

359

Effect of niloticin, a protolimonoid isolated from Limonia acidissima L. (Rutaceae) on the immature stages of dengue vector Aedes aegypti L. (Diptera: Culicidae).  

PubMed

The aim of the present study was to evaluate the mosquitocidal activity of fractions and a compound niloticin from the hexane extract of Limonia acidissima L. leaves on eggs, larvae and pupae of Aedes aegypti L. (Diptera: Culicidae). In these bioassays, the eggs, larvae and pupae were exposed to concentrations of 2.5, 5.0, 7.5 and 10.0ppm for fractions and 0.5, 1.0, 1.5 and 2.0ppm for compound. After 24h, the mortality was assessed and the LC50 and LC90 values were calculated for larvae and pupae. Per cent ovicidal activity was calculated for eggs after 120h post treatment. Among the sixteen fractions screened, fraction 8 from the hexane extract of L. acidissima generated good mosquitocidal activity against Ae. aegypti. The LC50 and LC90 values of fraction 8 were 4.11, 8.04ppm against Ae. aegypti larvae and 4.19, 8.10ppm against Ae. aegypti pupae, respectively. Further, the isolated compound, niloticin recorded strong larvicidal and pupicidal activities. The 2ppm concentration of niloticin showed 100% larvicidal and pupicidal activities in 24h. The LC50 and LC90 values of niloticin on Ae. aegypti larvae were 0.44, 1.17ppm and on pupae were 0.62, 1.45ppm, respectively. Niloticin presented 83.2% ovicidal activity at 2ppm concentration after 120h post treatment and niloticin exhibited significant growth disruption and morphological deformities at sub lethal concentrations against Ae. aegypti. The structure of the isolated compound was identified on the basis of single XRD and spectral data ((1)H NMR and (13)C NMR) and compared with literature spectral data. The results indicate that niloticin could be used as a potential natural mosquitocide. PMID:25019220

Reegan, Appadurai Daniel; Gandhi, Munusamy Rajiv; Paulraj, Micheal Gabriel; Balakrishna, Kedike; Ignacimuthu, Savarimuthu

2014-11-01

360

Effects of environmental conditions on the movement patterns of Aedes aegypti (Diptera: Culicidae) into and out of experimental huts in Thailand.  

PubMed

Mark-release-recapture experiments with Aedes aegypti were performed using experimental huts equipped with entrance and exit traps to evaluate their movement patterns during a two-year period in Thailand. Results indicate no significant differences in the patterns of movement between the two years of observation. Movement into the huts occurred during the early morning period (06:00-11:00) with a peak at 07:00 in the summer and rainy season and 09:00 in the winter. In contrast, the exit pattern was observed during the late morning (09:00-12:00) and early afternoon (12:00-16:00), with a peak at 16:00 in the winter, 11:00 in the summer, and 14:00 in the rainy season. Multiple regression analysis indicated that movements of Ae. aegypti females into and out of the huts were impacted by humidity and temperature during the day. PMID:20836830

Suwannachote, Nantawan; Grieco, John P; Achee, Nicole L; Suwonkerd, Wannapa; Wongtong, Somnuk; Chareonviriyaphap, Theeraphap

2009-12-01