Top PDF Alterations in the Aedes aegypti transcriptome during infection with West Nile, dengue and yellow fever viruses.

Alterations in the Aedes aegypti transcriptome during infection with West Nile, dengue and yellow fever viruses.

Alterations in the Aedes aegypti transcriptome during infection with West Nile, dengue and yellow fever viruses.

The majority of highly altered mosquito transcripts were not canonical innate immune genes though we were able to correlate our analysis with previous data on viral infection and mosquito immunity. Previous studies suggest that depleting PIAS (protein inhibitor of activated STAT), a negative regulator of the Jak- STAT pathway, resulted in down-regulation of five antimicrobial genes (four Cecropin A-like genes and one defensin l-like gene) that were also downregulated by DENV infection [9]. All five of these genes were significantly downregulated in our analysis during infection with all three flaviviruses infections at all three timepoints. One of these genes, AAEL000611, was highly downregulated late in infection, with 15-fold, 27-fold and 38-fold lower expression on D7 of YFV, DENV and WNV, respectively. Another Cecropin A-like gene, AAEL000627, was also highly downregulated on D7 of infection, with expression 14-fold, 14-fold and 41-fold lower during infection with YFV, DENV and WNV, respectively. This indicates that the mosquito Jak-STAT pathway is likely involved throughout infection with all three flaviviruses. This also suggests that YFV, DENV and WNV may have evolved a conserved mechanism to suppress this antiviral pathway during infection. The Toll pathway has also been previously implicated in anti-flaviviral defense by the mosquito [10]. One gene shown to be involved in the mosquito Toll pathway and downregulated by DENV, AAEL001929, was 2.5-fold lower on D1 of infection with YFV and 2.5-fold lower on D2 of DENV infection in our study. Another Toll gene, AAEL003507, was only significantly down- regulated during YFV infection, with 2.3-fold and 2.6-fold lower expression on D1 and D7, respectively. Our analysis also found a serine protease gene (AAEL006568) to be downregulated during infection with all three flaviviruses. Previous studies show that some midgut serine proteases limit DENV-2 infection in Aedes aegypti [19]. The Drosophila homolog of this
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Impact of Wolbachia on infection with chikungunya and yellow fever viruses in the mosquito vector Aedes aegypti.

Impact of Wolbachia on infection with chikungunya and yellow fever viruses in the mosquito vector Aedes aegypti.

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 10 4 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.
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Membrane and envelope virus proteins co-expressed as lysosome associated membrane protein (LAMP) fused antigens: a potential tool to develop DNA vaccines against flaviviruses

Membrane and envelope virus proteins co-expressed as lysosome associated membrane protein (LAMP) fused antigens: a potential tool to develop DNA vaccines against flaviviruses

Vaccination is the most practical and cost-effective strategy to prevent the majority of the flavivirus infection to which there is an available vaccine. However, vaccines based on attenuated virus can potentially promote collateral side effects and even rare fatal reactions. Given this scenario, the development of alternative vaccination strategies such as DNA-based vaccines encoding specific flavivirus sequences are being considered. Endogenous cytoplasmic anti- gens, characteristically plasmid DNA-vaccine encoded, are mainly presented to the immune system through Major Histocompatibility Complex class I – MHC I molecules. The MHC I presentation via is mostly associated with a cellular cytotoxic response and often do not elicit a satisfactory humoral response. One of the main strategies to target DNA-encoded antigens to the MHC II compartment is expressing the antigen within the Lysosome-Associated Mem- brane Protein (LAMP). The flavivirus envelope protein is recognized as the major virus surface protein and the main target for neutralizing antibodies. Different groups have demonstrated that co-expression of flavivirus membrane and envelope proteins in mammalian cells, fused with the carboxyl-terminal of LAMP, is able to induce satisfactory levels of neutralizing antibodies. Here we reviewed the use of the envelope flavivirus protein co-expression strategy as LAMP chimeras with the aim of developing DNA vaccines for dengue, West Nile and yellow fever viruses.
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Toxicity of Cry2 proteins from Bacillus thuringiensis subsp. thuringiensis strain T01-328 against Aedes aegypti (Diptera: Culicidae)

Toxicity of Cry2 proteins from Bacillus thuringiensis subsp. thuringiensis strain T01-328 against Aedes aegypti (Diptera: Culicidae)

Bacillus thuringiensis subsp. israelensis is highly relevant in the fight against the dengue vector, since it acts as an effi- cient biolarvicide integrated in the A. aegypti Control Program (PCA), conducted in several municipalities affected by the disease (BRAGA et al., 2004). In Rio de Janeiro, Ceará, and Rio Grande do Norte, it was recommended to replace the Temephos (organophosphorus) insecticide with biolarvicides based on B. thuringiensis subsp. israelensis, considered one of the most effective biological control agents against culicids (BRASIL, 2000). The larvicidal action of B. t huringiensis subsp. israelensis is achieved by the expression of the Cry4Aa, Cry4Ba, Cry11Aa, Cyt1Aa, Cry10Aa and Cyt2Ba proteins, whose synergistic action reduces the probability of resistance selection. Despite the lack of reports on the emergence of A. aegypti resistance to bioinsecticides based on this subspe- cies in the field, it is important to search proteins with alter- native action mode that can be used for controlling the mos- quito (BEN-DOV, 2014). Furthermore, it is also essential to study other B. thuringiensis subspecies pathogenic to A. aegypti
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Limited replication of yellow fever 17DD and 17D-Dengue recombinant viruses in rhesus monkeys

Limited replication of yellow fever 17DD and 17D-Dengue recombinant viruses in rhesus monkeys

For the development of safe live attenuated flavivirus vaccines one of the main properties to be established is viral replication. We have used real-time reverse transcriptase-polymerase chain reaction and virus titration by plaque assay to determine the replication of yellow fever 17DD virus (YFV 17DD) and recombinant yellow fever 17D viruses expressing envelope proteins of dengue virus serotypes 2 and 4 (17D-DENV-2 and 17D-DENV-4). Serum samples from rhesus monkeys inoculated with YFV 17DD and 17D-DENV chimeras by intracerebral or subcutaneous route were used to determine and compare the viremia induced by these viruses. Viral load quantification in samples from monkeys inoculated by either route with YFV 17DD virus suggested a restricted capability of the virus to replicate reaching not more than 2.0 log 10 PFU mL −1 or 3.29 log 10 copies mL −1 . Recombinant 17D-dengue viruses were shown by plaquing and real-time PCR to be as attenuated as YF 17DD virus with the highest mean peak titer of 1.97 log 10 PFU mL −1 or 3.53 log 10 copies mL −1 . These data serve as a comparative basis for the characterization of other 17D-based live attenuated candidate vaccines against other diseases.
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The "Aedes Aegypti" situation in the United States

The "Aedes Aegypti" situation in the United States

yellow fever and dengue mosquito, Aëdes aegypti, occurs commonly t,hroughout the southern United States. To most of us in t’his country it is just one more annoy[r]

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Rev. Soc. Bras. Med. Trop.  vol.44 número1

Rev. Soc. Bras. Med. Trop. vol.44 número1

he true epidemiological signiicance of the transmission of two or more serotypes by vectors that acquired the virus by transovarial transmission has yet to be established. he present results raise several questions related to the infectivity of these coinfected vectors, their signiicance in transmission during silent periods (interepidemic) and the relation between simultaneous infection by two serotypes and the clinical severity of cases. Virological and entomological surveillance detecting coinfected vectors in the ield could represent an important strategy for increasing current understanding of the various factors involved in the transmission and clinical presentation of dengue and improving the monitoring of the dynamic of its occurrence.
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Dengue haemorrhagic fever in pregnancy: appraisal on Thai cases

Dengue haemorrhagic fever in pregnancy: appraisal on Thai cases

nancy, of that no case was lethal. All except one case (23 wk pregnancy) had term pregnancy on presenta- tion. Average age of the patients was 23.6 + 8.2 yr. Concerning the clinical manifestations, all had fever and some had other manifestations (Table 1). From physical examination, all had hepatosplenomegaly and petichiae. At the time of diagnosis, complete blood count could demonstrate thrombocytopenia and haemoconcentration in all the cases.

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Rev. Soc. Bras. Med. Trop.  vol.49 número3

Rev. Soc. Bras. Med. Trop. vol.49 número3

1. Lounibos LP. Genetic-control trials and the ecology of Aedes aegypti at the Kenya coast. In: Takken W, Scott TW, editors. Ecological aspects for application of genetically modiied mosquitoes. Kluwer Academic Publishers, Dordrecht, The Netherlands, 2003. p. 33-43.

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Rev. Soc. Bras. Med. Trop.  vol.44 número4

Rev. Soc. Bras. Med. Trop. vol.44 número4

Vitória, the capital of Espírito Santo, is a coastal city 93.38 sq km in extent, consisting of Vitória Island and 34 smaller islands and a mainland portion. he municipality is part of the Greater Vitória Metropolitan Region, which concentrates 46% of the state population. he population census of the capital in 2000 was 282,606 inhabitants and the estimated population for the year 2009 was 320,156 inhabitants. he municipality has 79 districts, eight administrative regions and six healthcare regions. Its climate is tropical humid, with temperatures ranging on average between 24.4°C and 34.4°C. It produces 27.2% of the Gross Domestic Product, 29.6% of the consumption potential and 28.6% of the workforce employed in the state. In 2000, it had a human development index (HDI) of 0.856, an adult literacy rate of 95.5%, 99.5% of households with water supply, 89.8% with treated sewage and 99.6% with garbage collection 17 .
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Evaluation of Mesocyclops annulatus (Copepoda: Cyclopoidea) as a Control Agent of Aedes aegypti (Diptera: Culicidae) in Argentina

Evaluation of Mesocyclops annulatus (Copepoda: Cyclopoidea) as a Control Agent of Aedes aegypti (Diptera: Culicidae) in Argentina

We evaluated the potential of Mesocyclops annulatus as a control agent of Aedes aegypti in La Plata city (Argentina). Mosquito larval survivorship due to predation by these copepods was estimated at weekly intervals during the oviposition period of A. aegypti. Mean weekly A. aegypti larval survivorship in cylindrical plastic containers (12 cm height and 11 cm diameter) with copepods was significantly lower than in control containers. Furthermore, weekly larval survival was negatively correlated with M. annulatus adult density, and approximately 23 adult copepods/container would be a threshold density over which the weekly mosquito larval survivorship approached zero. The copepods were able to persist in all containers during approximately 100 days (in three of them until the end of the experiment: 155 days) without the resource represented by A. aegypti larvae. The predation and persistence observed suggest that M. annulatus is a potential control agent to be considered in biological control programs.
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Mosquitos

Mosquitos

(filariasis y dengue), Aedes aegypti (fiebre amarilla y dengue), Aedes (Ochlerotatus) scapularius y Aedes taeniorhynchus (fiebre amarilla, transmisores experimentales),[r]

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Genetic lineages in the yellow fever mosquito Aedes (Stegomyia) aegypti (Diptera: Culicidae) from Peru

Genetic lineages in the yellow fever mosquito Aedes (Stegomyia) aegypti (Diptera: Culicidae) from Peru

Concerning the low capacity of active dispersion of the Ae. aegypti mosquito (Trips & Hausermann 1986, Muir & Kay 1998), it was expected that the existence of a road connecting Piura and Lima (Fig. 1) could be an ultimate passive dispersion factor for the existence and maintenance of the genic flow and the genetic proximity between the populations of the two locations. Moreover, the isolation of Iquitos, caused by geographical and climatic (low tem- peratures) barriers represented by the Andes (Fig. 1) would be another determining factor to make the Piura and Lima samples more genetically closer between them when com- pared to Iquitos samples. However, this pattern could not be observed for the ND4 gene in these populations. Genetic relations between haplotype I from Lima and haplotypes II and III from Piura depicted in the network in Fig. 2 refute the hypotheses of higher genetic proximity of these two populations in comparison to Iquitos samples. This pattern of genetic distances non-related to geographical distances has already been described for Ae. aegypti. In a study with alozymes carried out in Argentinean populations, de Souza et al. (2000) showed that the three populations analyzed were genetically close. Nevertheless, the highest genetic distance observed was between the cities of Buenos Aires and Zárate, which were geographically closer.
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Rev. Soc. Bras. Med. Trop.  vol.46 número6

Rev. Soc. Bras. Med. Trop. vol.46 número6

Introduction : This study aimed to describe the clinical spectrum of dengue in children and adolescents from a hyperendemic region who were admitted for hospitalization. Methods: A retrospective study was conducted on patients diagnosed with dengue infection upon admission to a reference center in Fortaleza, Brazil. Results: Of the 84 patients included, 42 underwent confi rmatory testing. The main symptoms were fever, abdominal pain and vomiting. The median level of serum aspartate aminotransferase was 143.5±128mg/dL. Conclusions: A peculiar clinical profi le was evident among children and adolescents with dengue infection in a reference center in northeast Brazil, including gastrointestinal symptoms and liver involvement.
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Análise da estrutura populacional de Aedes aegytpi (Linnaeus, 1762) em algumas regiões do Brasil

Análise da estrutura populacional de Aedes aegytpi (Linnaeus, 1762) em algumas regiões do Brasil

Aedes aegypti is considered the main vector of arboviruses affecting humans. Nowadays, the only feasible measure to eradicate the dengue fever depends exclusively of vector control. The deep knowledge about the structure and dynamics of Ae. aegypti population in distinct environments is critical, since genetically different populations may present differences related to vector competence and capacity. Brazil has regions with different climatic and geographic characteristics, therefore, detailed knowledge about mosquito population that colonizes different habitats is extremely important. The present study evaluated the population structure of Ae. aegypti mosquitoes in five different Brazilian cities (i.e., Belo Horizonte, Botucatu, Campo Grande, Maringá and Rondonópolis) using a microsatellite markers. Those markers were also used to evaluate the oviposition dynamic and the consequences of Ae. aegypti mosquitoes dispersion, of the city of Botucatu. Population macro-analysis, using DAPC evidenced, genetic clusters among individuals of the same locality, and population structure in mosquitoes of Belo Horizonte. Population microstructure analysis identified six sub-populations of Ae. aegypti mosquitoes among six sub-regions of Belo Horizonte. In addition, the microstructure analysis suggested intermediate population structure in the sub-regions of Campo Grande, and lack of genetic structure among mosquitoes from the sub-regions of Botucatu. Therefore, these results indicate that genetic organization occurs in correlation with city size – where large towns seem to provide genetic structure to the populations of Ae. aegypti. PCA analysis of ovitraps obtained in Botucatu indicated population organization of Ae. aegypti mosquitoes in families. Pedigree analysis and inbreeding coefficient indicated that only for out of 30 mosquitoes analyzed in the same ovitrap, keep restricted familial relationships. These results suggest that Ae. aegypti females mates with mosquitoes geographically close, and scatter their eggs in different breeding sites, supporting the maintenance and dissemination of mosquitoes and, consequently the etiologic agents conveyed by them. The results of the present study assist in the understanding of Ae. aegipty mosquitoes dispersion. Also our study may facilitate the development of strategies for mosquito incidence reduction and dengue transmission reduction, helping solve the disease outbreaks that affects Brazil.
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Pharmacological and Genetic Evidence for Gap Junctions as Potential New Insecticide Targets in the Yellow Fever Mosquito, Aedes aegypti.

Pharmacological and Genetic Evidence for Gap Junctions as Potential New Insecticide Targets in the Yellow Fever Mosquito, Aedes aegypti.

Ideally, these mosquito-borne diseases could be prevented through the global use of safe, effective, and affordable vaccines. For yellow fever there is such a vaccine, however for chikun- gunya and dengue fevers there currently are no effective vaccines available [4]. An alternative strategy for controlling the spread of mosquito-borne diseases is to control populations of the mosquito vectors that transmit the pathogens. The primary control methods for reducing mos- quito numbers are sanitation (cleaning and removing larval habitats from around homes) and using insecticides [5]. Although insecticides are effective at reducing mosquito populations, insecticide resistant populations have emerged because of the overuse of a few limited active compounds, such as pyrethroids [6]. The control of resistant populations of mosquitoes can be mitigated through a variety of techniques, including the development of new insecticides with novel modes of action, which begins with the identification of new insecticidal targets.
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Rev. Saúde Pública  vol.37 número5

Rev. Saúde Pública vol.37 número5

The fir st r ecor d of Aedes albopict us in Br azil w as in 1986, in t he St at e of Rio de Janeir o. 2 I n t hat sam e year , t he species w as t hen found in Minas Ger ais and São Paulo and, in t he follow ing year , in Espír it o San t o. 1 Thus, w it hin j ust one y ear , Ae. albopict u s had becom e est ablished in all t he st at es of t he sout heast er n r egion.

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Detecção de Aedes aegypti e Aedes albopictus, na zona urbana do município de Catanduva-SP, após controle de epidemia de dengue.

Detecção de Aedes aegypti e Aedes albopictus, na zona urbana do município de Catanduva-SP, após controle de epidemia de dengue.

Após a realização dos trabalhos de controle visando à interrupção da transmissão do vírus do dengue, iniciou-se um trabalho de monitorização de Aedes aegypti e Aedes albopictus com dois métodos de vigilância entomológica: Índice de Breteau (IB) e ovitrampas. Pretendeu-se avaliar o tempo necessário para que as espécies envolvidas fossem novamente detectadas na área urbana do município de Catanduva, SP. As ovitrampas apresentaram positividade para Aedes aegypti dois meses após os trabalhos de controle, enquanto o Índice de Breteau veio a positivar-se somente no quarto mês após o término dos referidos trabalhos.
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Rev. Saúde Pública  vol.42 número6

Rev. Saúde Pública vol.42 número6

METHODS: Eighteen households were randomly selected for egg collection in a neighborhood of the city of Boa Vista, Roraima, in Northern Brazil. Two oviposition traps were installed per home, and removed after one week. This was repeated on a monthly basis between November 2006 and May 2007. Trap positivity rate and egg density were calculated. Following the eclosion of 1,422 eggs, 44 pools of at least 30 larvae each were formed, which were evaluated for presence of dengue virus using RT-PCR and hemi-nested PCR. Dengue incidence rates in the period were correlated with rainfall rates. The association between these two variables and the number of eggs collected was determined using Pearson correlation.
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Rev. Saúde Pública  vol.43 número1

Rev. Saúde Pública vol.43 número1

out for 18 days. All collected mosquitoes were brought to the laboratory to be identifi ed and checked for the presence of fl uorescent mark with an UV light. As for dispersal, the 192 houses where mosquito traps were installed were geo-referenced using a Global Posi- tion System (GPS; Garmin eTrex personal navigator) to calculate distance between releasing and capture points. The fl ight behavior of Ae. aegypti females was sum- marized by a set of dispersal measures: mean distance traveled (MDT), maximum distance traveled (MAX), and fl ight ranges of 50% (FR 50 ) and 90% (FR 90 ) of the population. 11,16 Frequency distributions of the marked
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