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1.
Sci Rep ; 12(1): 9536, 2022 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-35681077

RESUMO

Mosquito saliva facilitates blood feeding through the anti-haemostatic, anti-inflammatory and immunomodulatory properties of its proteins. However, the potential contribution of non-coding RNAs to host manipulation is still poorly understood. We analysed small RNAs from Aedes aegypti saliva and salivary glands and show here that chikungunya virus-infection triggers both the siRNA and piRNA antiviral pathways with limited effects on miRNA expression profiles. Saliva appears enriched in specific miRNA subsets and its miRNA content is well conserved among mosquitoes and ticks, clearly pointing to a non-random sorting and occurrence. Finally, we provide evidence that miRNAs from Ae. aegypti saliva may target human immune and inflammatory pathways, as indicated by prediction analysis and searching for experimentally validated targets of identical human miRNAs. Overall, we believe these observations convincingly support a scenario where both proteins and miRNAs from mosquito saliva are injected into vertebrates during blood feeding and contribute to the complex vector-host-pathogen interactions.


Assuntos
Aedes , Vírus Chikungunya , MicroRNAs , Aedes/genética , Aedes/virologia , Animais , Febre de Chikungunya , Humanos , MicroRNAs/genética , Mosquitos Vetores/genética , Mosquitos Vetores/virologia , RNA Interferente Pequeno/genética , Saliva , Glândulas Salivares/metabolismo
2.
J Virol ; 96(10): e0016522, 2022 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-35467365

RESUMO

Zika virus is a mosquito-borne flavivirus known to cause severe birth defects and neuroimmunological disorders. We have previously demonstrated that mosquito transmission of Zika virus decreases with temperature. While transmission was optimized at 29°C, it was limited at cool temperatures (<22°C) due to poor virus establishment in the mosquitoes. Temperature is one of the strongest drivers of vector-borne disease transmission due to its profound effect on ectothermic mosquito vectors, viruses, and their interaction. Although there is substantial evidence of temperature effects on arbovirus replication and dissemination inside mosquitoes, little is known about whether temperature affects virus replication directly or indirectly through mosquito physiology. In order to determine the mechanisms behind temperature-induced changes in Zika virus transmission potential, we investigated different steps of the virus replication cycle in mosquito cells (C6/36) at optimal (28°C) and cool (20°C) temperatures. We found that the cool temperature did not alter Zika virus entry or translation, but it affected genome replication and reduced the amount of double-stranded RNA replication intermediates. If replication complexes were first formed at 28°C and the cells were subsequently shifted to 20°C, the late steps in the virus replication cycle were efficiently completed. These data suggest that cool temperature decreases the efficiency of Zika virus genome replication in mosquito cells. This phenotype was observed in the Asian lineage of Zika virus, while the African lineage Zika virus was less restricted at 20°C. IMPORTANCE With half of the human population at risk, arboviral diseases represent a substantial global health burden. Zika virus, previously known to cause sporadic infections in humans, emerged in the Americas in 2015 and quickly spread worldwide. There was an urgent need to better understand the disease pathogenesis and develop therapeutics and vaccines, as well as to understand, predict, and control virus transmission. In order to efficiently predict the seasonality and geography for Zika virus transmission, we need a deeper understanding of the host-pathogen interactions and how they can be altered by environmental factors such as temperature. Identifying the step in the virus replication cycle that is inhibited under cool conditions can have implications in modeling the temperature suitability for arbovirus transmission as global environmental patterns change. Understanding the link between pathogen replication and environmental conditions can potentially be exploited to develop new vector control strategies in the future.


Assuntos
Aedes , Temperatura , Replicação Viral , Zika virus , Aedes/virologia , Animais , Mosquitos Vetores/virologia , Zika virus/fisiologia
3.
Ecohealth ; 19(1): 75-84, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35318521

RESUMO

Dengue virus (DENV) 1-4 is the etiological agent of dengue, the most important viral infection transmitted by Aedes spp mosquitoes to humans. Our goal was to identify the circulating DENV in Aedes aegypti collected in an area of Brazil where all four DENV serotypes had already been detected in humans, understand the epidemiology better, and to test the vector as a virological surveillance tool. Twenty-eight larvae pools and 174 females of Aedes aegypti were screened by reverse transcriptase quantitative polymerase chain reaction and semi-nested PCR assays. PCR products were sequenced, and phylogenetic analyses were performed. Nine larvae pools (32.1%) were positive for DENV, four (44.4%) with DENV-3, and five (55.6%) with more than one serotype. Fifteen females (8.6%) were positive for any DENV serotype. DENV-1 isolates belong to genotype V, DENV-2 to American-Asian genotype, DENV-3 to genotypes I and III, and DENV-4 to genotypes I and II. We demonstrate for the first time the co-circulation of all four DENV serotypes in larvae pools and adult Aedes aegypti in a hyperendemic area. This scenario represents a challenge for disease control and reinforces the importance of virological surveillance in the vector as a tool for predicting circulating DENV serotypes in humans.


Assuntos
Aedes , Vírus da Dengue , Dengue , Aedes/virologia , Animais , Brasil , Dengue/epidemiologia , Vírus da Dengue/genética , Feminino , Larva , Mosquitos Vetores/virologia , Filogenia , Sorogrupo
4.
mSphere ; 7(1): e0100321, 2022 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-35171691

RESUMO

Arboviruses transmitted by mosquitoes are responsible for the death of millions of people each year. In addition to arboviruses, many insect-specific viruses (ISVs) have been discovered in mosquitoes in the last decade. ISVs, in contrast to arboviruses transmitted by mosquitoes to vertebrates, cannot replicate in vertebrate cells even when they are evolutionarily closely related to arboviruses. The alphavirus genus includes many arboviruses, although only a few ISVs have been discovered from this genus so far. Here, we investigate the interactions of a recently isolated insect-specific alphavirus, Agua Salud alphavirus (ASALV), with its mosquito host. RNA interference (RNAi) is one of the essential antiviral responses against arboviruses, although there is little knowledge on the interactions of RNAi with ISVs. Through the knockdown of transcripts of the different key RNAi pathway (small interfering RNA [siRNA], microRNA [miRNA], and P-element-induced wimpy testis [PIWI]-interacting RNA [piRNA]) proteins, we show the antiviral role of Ago2 (siRNA), Ago1 (miRNA), and Piwi4 proteins against ASALV in Aedes aegypti-derived cells. ASALV replication was increased in Dicer2 and Ago2 knockout cells, confirming the antiviral role of the siRNA pathway. In infected cells, mainly ASALV-specific siRNAs are produced, while piRNA-like small RNAs, with the characteristic nucleotide bias resulting from ping-pong amplification, are produced only in Dicer2 knockout cells. Taken together, ASALV interactions with the mosquito RNAi response differ from those of arthropod-borne alphaviruses in some aspects, although they also share some commonalities. Further research is needed to understand whether the identified differences can be generalized to other insect-specific alphaviruses. IMPORTANCE Mosquitoes are efficient vectors for many arboviruses that cause emergent infectious diseases in humans. Many insect-specific viruses (ISVs) that can infect mosquitoes but cannot infect vertebrates have been discovered in the last decade. ISVs have attracted great attention due to their potential use in mosquito or arbovirus control, by either decreasing mosquito fitness or restricting arbovirus replication and transmission to humans. However, ISV-mosquito interactions are not well understood. RNA interference (RNAi) is the most important innate immune response against many arboviruses, while it is unknown if it is antiviral against ISVs. Here, we investigate in detail the antiviral effect of the RNAi response in mosquitoes against an ISV for the first time. Using a recently isolated insect-specific alphavirus, we show that the regulation of virus replication was different from that for arthropod-borne alphaviruses despite some similarities. The differences in mosquito-virus interactions could drive the different transmission modes, which could eventually drive the evolution of arboviruses. Hence, an understanding of mosquito-ISV interactions can shed light on the ecology and evolution of both ISVs and the medically important arboviruses.


Assuntos
Aedes , Alphavirus , Arbovírus , Vírus de Insetos , MicroRNAs , Aedes/genética , Aedes/virologia , Alphavirus/genética , Animais , Antivirais , Arbovírus/fisiologia , Linhagem Celular , Mosquitos Vetores/virologia , Interferência de RNA , RNA de Cadeia Dupla , RNA Interferente Pequeno/genética
5.
Toxins (Basel) ; 14(2)2022 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-35202174

RESUMO

Mosquito densoviruses (MDVs) are mosquito-specific viruses that are recommended as mosquito bio-control agents. The MDV Aedes aegypti densovirus (AeDNV) is a good candidate for controlling mosquitoes. However, the slow activity restricts their widespread use for vector control. In this study, we introduced the Bacillus thuringiensis (Bti) toxin Cry11Aa domain II loop α8 and Cyt1Aa loop ß6-αE peptides into the AeDNV genome to improve its mosquitocidal efficiency; protein expression was confirmed using nanoscale liquid chromatography coupled to tandem mass spectrometry (nano LC-MS/MS). Recombinant plasmids were transfected into mosquito C6/36 cell lines, and the expression of specific peptides was detected through RT-PCR. A toxicity bioassay against the first instar Aedes albopictus larvae revealed that the pathogenic activity of recombinant AeDNV was significantly higher and faster than the wild-type (wt) viruses, and mortality increased in a dose-dependent manner. The recombinant viruses were genetically stable and displayed growth phenotype and virus proliferation ability, similar to wild-type AeDNV. Our novel results offer further insights by combining two mosquitocidal pathogens to improve viral toxicity for mosquito control.


Assuntos
Aedes/efeitos dos fármacos , Aedes/virologia , Toxinas de Bacillus thuringiensis/toxicidade , Agentes de Controle Biológico , Densovirus/patogenicidade , Larva/efeitos dos fármacos , Mosquitos Vetores/efeitos dos fármacos , Animais , China , Densovirus/genética , Controle de Mosquitos/métodos , Mosquitos Vetores/virologia , Virulência/efeitos dos fármacos
6.
Virology ; 568: 49-55, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35114499

RESUMO

West Nile virus (WNV) overwintering is poorly understood and likely multifactorial. Interest in alligators as a potential amplifying host arose when it was shown that they develop viremias theoretically sufficient to infect mosquitoes. We examined potential ways in which alligators may contribute to the natural ecology of WNV. We experimentally demonstrated that alligators are capable of WNV amplification with subsequent mosquito infection and transmission capability, that WNV-infected mosquitoes readily infect alligators and that water can serve as a source of infection for alligators but does not easily serve as in intermediate means for transmission between birds and alligators. These findings indicate potential mechanisms for maintenance of WNV outside of the primary bird-mosquito transmission cycle.


Assuntos
Jacarés e Crocodilos/virologia , Culicidae/virologia , Mosquitos Vetores/virologia , Replicação Viral , Febre do Nilo Ocidental/transmissão , Vírus do Nilo Ocidental/fisiologia , Animais , Aves/virologia , Chlorocebus aethiops , Reservatórios de Doenças/virologia , Células Vero , Zoonoses Virais , Febre do Nilo Ocidental/virologia
7.
Comput Math Methods Med ; 2022: 5118382, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35178113

RESUMO

In this paper, a nonlinear fractional-order chikungunya disease model that incorporates asymptomatic infectious individuals is proposed and analyzed. The main interest of this work is to investigate the role of memory effects on the dynamics of chikungunya. Qualitative analysis of the model's equilibria showed that there exists a threshold quantity which governs persistence and extinction of the disease. Model parameters were estimated based on the 2015 weekly reported cases in Colombia. The Adams-Bashforth-Moulton method was used to numerically solve the proposed model. We investigated the role of asymptomatic infectious patients on short- and long-term dynamics of the diseases. We also determined threshold levels for the efficacy of preventative strategies that results in effective management of the disease. We believe that our model can provide invaluable insights for public health authorities to predict the effect of chikungunya transmission and analyze its underlying factors and to guide new control efforts.


Assuntos
Febre de Chikungunya/epidemiologia , Animais , Infecções Assintomáticas/epidemiologia , Febre de Chikungunya/prevenção & controle , Febre de Chikungunya/transmissão , Biologia Computacional , Simulação por Computador , Humanos , Mosquitos Vetores/virologia , Dinâmica não Linear
8.
PLoS Negl Trop Dis ; 16(2): e0010206, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35139066

RESUMO

The tiger mosquito was introduced to the Eastern region of the Mediterranean basin more than twenty years ago. In Lebanon, it was first observed in 2002 in a limited number of locations mainly from the coastal area of the country. In the absence of national entomological control program, this invasive mosquito became an established species and is now considered in many localities, a source of nuisance because of its human biting behavior. Several entomological surveys were conducted to monitor the geographic spread and the seasonal dynamics of Aedes albopictus by collecting adult stages and by monitoring oviposition activity. Moreover, its susceptibility to the common groups of insecticides was assessed using WHO standard bioassays. Previous vector competence studies revealed that local strains were able to transmit Chikungunya and Dengue viruses. Due to the increased risk of Zika virus introduction in the country, we determined the competence of local populations to transmit this virus. Mapping results showed that Ae. albopictus is mainly spread in the relatively humid western versant of the Mount Lebanon chain reaching 1000m altitude, while it is absent from arid and semi-arid inland areas. Besides, this mosquito is active during 32 weeks from spring till the end of autumn. Local strains of the tiger mosquito are susceptible to pyrethroids and carbamates but resistant to organophosphates and organochlorines. They showed ability to transmit Zika virus; however, only 9% of females were capable to excrete the virus in their saliva at day 28 post infection. Current and previous observations highlight the need to establish a surveillance system in order to control this mosquito and monitor the potential introduction of related diseases.


Assuntos
Aedes/fisiologia , Espécies Introduzidas/estatística & dados numéricos , Mosquitos Vetores/fisiologia , Aedes/efeitos dos fármacos , Aedes/virologia , Distribuição Animal , Animais , Vírus da Dengue/genética , Vírus da Dengue/isolamento & purificação , Feminino , Inseticidas/farmacologia , Líbano , Masculino , Mosquitos Vetores/efeitos dos fármacos , Mosquitos Vetores/virologia , Piretrinas/farmacologia , Saliva/virologia , Estações do Ano , Zika virus/genética , Zika virus/isolamento & purificação
9.
Viruses ; 14(2)2022 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-35215949

RESUMO

Mosquito-borne viruses (MBVs), also known as moboviruses, are associated mainly with mosquitoes and are able to infect humans and other vertebrates [...].


Assuntos
Ecologia , Mosquitos Vetores/virologia , Aedes/fisiologia , Aedes/virologia , Animais , Infecções por Arbovirus/prevenção & controle , Infecções por Arbovirus/transmissão , Infecções por Arbovirus/virologia , Arbovírus/fisiologia , Humanos , Mosquitos Vetores/fisiologia
10.
Viruses ; 14(2)2022 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-35215815

RESUMO

Aedes aegypti mosquitoes are important vectors of several debilitating and deadly arthropod-borne (arbo) viruses, including Yellow Fever virus, Dengue virus, West Nile virus and Zika virus (ZIKV). Arbovirus transmission occurs when an infected mosquito probes the host's skin in search of a blood meal. Salivary proteins from mosquitoes help to acquire blood and have also been shown to enhance pathogen transmission in vivo and in vitro. Here, we evaluated the interaction of mosquito salivary proteins with ZIKV by surface plasmon resonance and enzyme-linked immunosorbent assay. We found that three salivary proteins AAEL000793, AAEL007420, and AAEL006347 bind to the envelope protein of ZIKV with nanomolar affinities. Similar results were obtained using virus-like particles in binding assays. These interactions have no effect on viral replication in cultured endothelial cells and keratinocytes. Additionally, we found detectable antibody levels in ZIKV and DENV serum samples against the recombinant proteins that interact with ZIKV. These results highlight complex interactions between viruses, salivary proteins and antibodies that could be present during viral transmissions.


Assuntos
Aedes/metabolismo , Proteínas de Insetos/metabolismo , Mosquitos Vetores/metabolismo , Proteínas e Peptídeos Salivares/metabolismo , Proteínas do Envelope Viral/metabolismo , Zika virus/metabolismo , Aedes/química , Aedes/genética , Aedes/virologia , Animais , Células Endoteliais/metabolismo , Células Endoteliais/virologia , Proteínas de Insetos/química , Proteínas de Insetos/genética , Queratinócitos/metabolismo , Queratinócitos/virologia , Cinética , Mosquitos Vetores/química , Mosquitos Vetores/genética , Mosquitos Vetores/virologia , Ligação Proteica , Proteínas e Peptídeos Salivares/química , Proteínas e Peptídeos Salivares/genética , Proteínas do Envelope Viral/química , Proteínas do Envelope Viral/genética , Replicação Viral , Zika virus/química , Zika virus/genética
11.
Viruses ; 14(2)2022 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-35216028

RESUMO

Emerging and re-emerging mosquito-borne viral diseases impose a significant burden on global public health. The most common mosquito-borne viruses causing recent epidemics include flaviviruses in the family Flaviviridae, including Dengue virus (DENV), Zika virus (ZIKV), Japanese encephalitis virus (JEV) and West Nile virus (WNV) and Togaviridae viruses, such as chikungunya virus (CHIKV). Several factors may have contributed to the recent re-emergence and spread of mosquito-borne viral diseases. Among these important causes are the evolution of mosquito-borne viruses and the genetic mutations that make them more adaptive and virulent, leading to widespread epidemics. RNA viruses tend to acquire genetic diversity due to error-prone RNA-dependent RNA polymerases, thus promoting high mutation rates that support adaptation to environmental changes or host immunity. In this review, we discuss recent findings on the adaptive evolution of mosquito-borne viruses and their impact on viral infectivity, pathogenicity, vector fitness, transmissibility, epidemic potential and disease emergence.


Assuntos
Culicidae/virologia , Flavivirus/fisiologia , Mosquitos Vetores/virologia , Doenças Transmitidas por Vetores/virologia , Animais , Evolução Biológica , Culicidae/imunologia , Epidemias , Flavivirus/classificação , Flavivirus/imunologia , Humanos , Replicação Viral
12.
Sci Rep ; 12(1): 571, 2022 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-35022501

RESUMO

Dengue remains a major public threat and existing dengue control/surveillance programs lack sensitivity and proactivity. More efficient methods are needed. A cluster randomized controlled trial was conducted for 18 months to determine the efficacy of using a combination of gravid oviposition sticky (GOS) traps and dengue non-structural 1 (NS1) antigen for early surveillance of dengue among Aedes mosquito. Eight residential apartments were randomly assigned into intervention and control groups. GOS traps were placed at the intervention apartments weekly to trap Aedes mosquitoes and these tested for dengue NS1 antigen. When dengue-positive pool was detected, the community were notified and advised to execute protective measures. Fewer dengue cases were recorded in the intervention group than the control. Detection of NS1-positive mosquitoes was significantly associated with GOS Aedes index (rs = 0.68, P < 0.01) and occurrence of dengue cases (rs = 0.31, P < 0.01). Participants' knowledge, attitude, and practice (KAP) toward dengue control indicated significant improvement for knowledge (P < 0.01), practice (P < 0.01) and total scores (P < 0.01). Most respondents thought this surveillance method is good (81.2%) and supported its use nationwide. Thus, GOS trap and dengue NS1 antigen test can supplement the current dengue surveillance/control, in alignment with the advocated integrated vector management for reducing Aedes-borne diseases.


Assuntos
Aedes/virologia , Dengue/prevenção & controle , Controle de Mosquitos/instrumentação , Mosquitos Vetores/virologia , Proteínas não Estruturais Virais/isolamento & purificação , Animais , Dengue/epidemiologia , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Malásia/epidemiologia , Masculino , Controle de Mosquitos/estatística & dados numéricos , Vigilância da População/métodos
14.
Parasit Vectors ; 15(1): 36, 2022 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-35073977

RESUMO

BACKGROUND: Aedes albopictus and Aedes japonicus, two invasive mosquito species in the United States, are implicated in the transmission of arboviruses. Studies have shown interactions of these two mosquito species with a variety of vertebrate hosts; however, regional differences exist and may influence their contribution to arbovirus transmission. METHODS: We investigated the distribution, abundance, host interactions, and West Nile virus infection prevalence of Ae. albopictus and Ae. japonicus by examining Pennsylvania mosquito and arbovirus surveillance data for the period between 2010 and 2018. Mosquitoes were primarily collected using gravid traps and BG-Sentinel traps, and sources of blood meals were determined by analyzing mitochondrial cytochrome b gene sequences amplified in PCR assays. RESULTS: A total of 10,878,727 female mosquitoes representing 51 species were collected in Pennsylvania over the 9-year study period, with Ae. albopictus and Ae. japonicus representing 4.06% and 3.02% of all collected mosquitoes, respectively. Aedes albopictus was distributed in 39 counties and Ae. japonicus in all 67 counties, and the abundance of these species increased between 2010 and 2018. Models suggested an increase in the spatial extent of Ae. albopictus during the study period, while that of Ae. japonicus remained unchanged. We found a differential association between the abundance of the two mosquito species and environmental conditions, percent development, and median household income. Of 110 Ae. albopictus and 97 Ae. japonicus blood meals successfully identified to species level, 98% and 100% were derived from mammalian hosts, respectively. Among 12 mammalian species, domestic cats, humans, and white-tailed deer served as the most frequent hosts for the two mosquito species. A limited number of Ae. albopictus acquired blood meals from avian hosts solely or in mixed blood meals. West Nile virus was detected in 31 pools (n = 3582 total number of pools) of Ae. albopictus and 12 pools (n = 977 total pools) of Ae. japonicus. CONCLUSIONS: Extensive distribution, high abundance, and frequent interactions with mammalian hosts suggest potential involvement of Ae. albopictus and Ae. japonicus in the transmission of human arboviruses including Cache Valley, Jamestown Canyon, La Crosse, dengue, chikungunya, and Zika should any of these viruses become prevalent in Pennsylvania. Limited interaction with avian hosts suggests that Ae. albopictus might occasionally be involved in transmission of arboviruses such as West Nile in the region.


Assuntos
Aedes , Infecções por Arbovirus/transmissão , Comportamento Alimentar , Mosquitos Vetores , Análise Espaço-Temporal , Aedes/fisiologia , Aedes/virologia , Animais , Arbovírus , Aves/virologia , Febre de Chikungunya/transmissão , Cervos/virologia , Reservatórios de Doenças/virologia , Humanos , Espécies Introduzidas , Mamíferos/virologia , Mosquitos Vetores/fisiologia , Mosquitos Vetores/virologia , Pennsylvania , Densidade Demográfica , Especificidade da Espécie , Vírus do Nilo Ocidental , Zika virus , Infecção por Zika virus/transmissão , Zoonoses/virologia
15.
Int J Mol Sci ; 23(2)2022 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-35055061

RESUMO

Understanding the flavivirus infection process in mosquito hosts is important and fundamental in the search for novel control strategies that target the mosquitoes' ability to carry and transmit pathogenic arboviruses. A group of viruses known as insect-specific viruses (ISVs) has been shown to interfere with the infection and replication of a secondary arbovirus infection in mosquitoes and mosquito-derived cell lines. However, the molecular mechanisms behind this interference are unknown. Therefore, in the present study, we infected the Aedes albopictus cell line U4.4 with either the West Nile virus (WNV), the insect-specific Lammi virus (LamV) or an infection scheme whereby cells were pre-infected with LamV 24 h prior to WNV challenge. The qPCR analysis showed that the dual-infected U4.4 cells had a reduced number of WNV RNA copies compared to WNV-only infected cells. The transcriptome profiles of the different infection groups showed a variety of genes with altered expression. WNV-infected cells had an up-regulation of a broad range of immune-related genes, while in LamV-infected cells, many genes related to stress, such as different heat-shock proteins, were up-regulated. The transcriptome profile of the dual-infected cells was a mix of up- and down-regulated genes triggered by both viruses. Furthermore, we observed an up-regulation of signal peptidase complex (SPC) proteins in all infection groups. These SPC proteins have shown importance for flavivirus assembly and secretion and could be potential targets for gene modification in strategies for the interruption of flavivirus transmission by mosquitoes.


Assuntos
Aedes/genética , Aedes/virologia , Perfilação da Expressão Gênica , Interações Hospedeiro-Patógeno/genética , Transcriptoma , Animais , Coinfecção , Biologia Computacional/métodos , Flavivirus , Perfilação da Expressão Gênica/métodos , Ontologia Genética , Mosquitos Vetores/genética , Mosquitos Vetores/virologia , Reação em Cadeia da Polimerase em Tempo Real , Febre do Nilo Ocidental/transmissão , Febre do Nilo Ocidental/virologia , Vírus do Nilo Ocidental
16.
Parasit Vectors ; 15(1): 23, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-35012637

RESUMO

BACKGROUND: Yellow fever virus (YFV) is an arbovirus that, despite the existence of a safe and effective vaccine, continues to cause outbreaks of varying dimensions in the Americas and Africa. Between 2017 and 2019, Brazil registered un unprecedented sylvatic YFV outbreak whose severity was the result of its spread into zones of the Atlantic Forest with no signals of viral circulation for nearly 80 years. METHODS: To investigate the influence of climatic, environmental, and ecological factors governing the dispersion and force of infection of YFV in a naïve area such as the landscape mosaic of Rio de Janeiro (RJ), we combined the analyses of a large set of data including entomological sampling performed before and during the 2017-2019 outbreak, with the geolocation of human and nonhuman primates (NHP) and mosquito infections. RESULTS: A greater abundance of Haemagogus mosquitoes combined with lower richness and diversity of mosquito fauna increased the probability of finding a YFV-infected mosquito. Furthermore, the analysis of functional traits showed that certain functional groups, composed mainly of Aedini mosquitoes which includes Aedes and Haemagogus mosquitoes, are also more representative in areas where infected mosquitoes were found. Human and NHP infections were more common in two types of landscapes: large and continuous forest, capable of harboring many YFV hosts, and patches of small forest fragments, where environmental imbalance can lead to a greater density of the primary vectors and high human exposure. In both, we show that most human infections (~ 62%) occurred within an 11-km radius of the finding of an infected NHP, which is in line with the flight range of the primary vectors. CONCLUSIONS: Together, our data suggest that entomological data and landscape composition analyses may help to predict areas permissive to yellow fever outbreaks, allowing protective measures to be taken to avoid human cases.


Assuntos
Brasil , Culicidae , Surtos de Doenças , Mosquitos Vetores , Febre Amarela/transmissão , Aedes/crescimento & desenvolvimento , Aedes/virologia , Animais , Biodiversidade , Brasil/epidemiologia , Clima , Culicidae/crescimento & desenvolvimento , Culicidae/virologia , Florestas , Humanos , Mosquitos Vetores/classificação , Mosquitos Vetores/crescimento & desenvolvimento , Mosquitos Vetores/virologia , Fatores de Risco , Febre Amarela/epidemiologia
17.
Mol Cell Biochem ; 477(3): 815-832, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35059925

RESUMO

Dengue viruses (DENVs) are the viruses responsible for dengue infection which affects lungs, liver, heart and also other organs of individuals. DENVs consist of the group of four serotypically diverse dengue viruses transmitted in tropical and sub-tropical countries of world. Aedes mosquito is the principal vector which spread the infection from infected person to healthy humans. DENVs can cause different syndromes depending on serotype of virus which range from undifferentiated mild fever to dengue hemorrhagic fever resulting in vascular leakage due to release of cytokine and Dengue shock syndrome with fluid loss and hypotensive shock, or other severe manifestations such as bleeding and organ failure. Increase in dengue cases in pediatric population is a major concern. Transmission of dengue depends on various factors like temperature, rainfall, and distribution of Aedes aegypti mosquitoes. The present review describes a comprehensive overview of dengue, pathophysiology, diagnosis, treatment with an emphasis on potential of exosomes as biomarkers for early prediction of dengue in pediatrics.


Assuntos
Vírus da Dengue/metabolismo , Dengue/sangue , Exossomos/metabolismo , Aedes/virologia , Animais , Biomarcadores/sangue , Dengue/diagnóstico , Dengue/transmissão , Humanos , Mosquitos Vetores/virologia , Prognóstico
18.
PLoS Pathog ; 18(1): e1010202, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34990484

RESUMO

The exogenous small interfering RNA (exo-siRNA) pathway is a key antiviral mechanism in the Aedes aegypti mosquito, a widely distributed vector of human-pathogenic arboviruses. This pathway is induced by virus-derived double-stranded RNAs (dsRNA) that are cleaved by the ribonuclease Dicer 2 (Dcr2) into predominantly 21 nucleotide (nt) virus-derived small interfering RNAs (vsiRNAs). These vsiRNAs are used by the effector protein Argonaute 2 within the RNA-induced silencing complex to cleave target viral RNA. Dcr2 contains several domains crucial for its activities, including helicase and RNase III domains. In Drosophila melanogaster Dcr2, the helicase domain has been associated with binding to dsRNA with blunt-ended termini and a processive siRNA production mechanism, while the platform-PAZ domains bind dsRNA with 3' overhangs and subsequent distributive siRNA production. Here we analyzed the contributions of the helicase and RNase III domains in Ae. aegypti Dcr2 to antiviral activity and to the exo-siRNA pathway. Conserved amino acids in the helicase and RNase III domains were identified to investigate Dcr2 antiviral activity in an Ae. aegypti-derived Dcr2 knockout cell line by reporter assays and infection with mosquito-borne Semliki Forest virus (Togaviridae, Alphavirus). Functionally relevant amino acids were found to be conserved in haplotype Dcr2 sequences from field-derived Ae. aegypti across different continents. The helicase and RNase III domains were critical for silencing activity and 21 nt vsiRNA production, with RNase III domain activity alone determined to be insufficient for antiviral activity. Analysis of 21 nt vsiRNA sequences (produced by functional Dcr2) to assess the distribution and phasing along the viral genome revealed diverse yet highly consistent vsiRNA pools, with predominantly short or long sequence overlaps including 19 nt overlaps (the latter representing most likely true Dcr2 cleavage products). Combined with the importance of the Dcr2 helicase domain, this suggests that the majority of 21 nt vsiRNAs originate by processive cleavage. This study sheds new light on Ae. aegypti Dcr2 functions and properties in this important arbovirus vector species.


Assuntos
Aedes/imunologia , Aedes/virologia , Infecções por Alphavirus/imunologia , Ribonuclease III/imunologia , Aedes/genética , Animais , Análise Mutacional de DNA , Mosquitos Vetores/virologia , RNA Interferente Pequeno/imunologia , RNA Viral/imunologia , Ribonuclease III/genética , Vírus da Floresta de Semliki
19.
PLoS Negl Trop Dis ; 16(1): e0010075, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35007285

RESUMO

BACKGROUND: West Nile virus is a mosquito-borne flavivirus which has been posing continuous challenges to public health worldwide due to the identification of new lineages and clades and its ability to invade and establish in an increasing number of countries. Its current distribution, genetic variability, ecology, and epidemiological pattern in the African continent are only partially known despite the general consensus on the urgency to obtain such information for quantifying the actual disease burden in Africa other than to predict future threats at global scale. METHODOLOGY AND PRINCIPAL FINDINGS: References were searched in PubMed and Google Scholar electronic databases on January 21, 2020, using selected keywords, without language and date restriction. Additional manual searches of reference list were carried out. Further references have been later added accordingly to experts' opinion. We included 153 scientific papers published between 1940 and 2021. This review highlights: (i) the co-circulation of WNV-lineages 1, 2, and 8 in the African continent; (ii) the presence of diverse WNV competent vectors in Africa, mainly belonging to the Culex genus; (iii) the lack of vector competence studies for several other mosquito species found naturally infected with WNV in Africa; (iv) the need of more competence studies to be addressed on ticks; (iv) evidence of circulation of WNV among humans, animals and vectors in at least 28 Countries; (v) the lack of knowledge on the epidemiological situation of WNV for 19 Countries and (vii) the importance of carrying out specific serological surveys in order to avoid possible bias on WNV circulation in Africa. CONCLUSIONS: This study provides the state of art on WNV investigation carried out in Africa, highlighting several knowledge gaps regarding i) the current WNV distribution and genetic diversity, ii) its ecology and transmission chains including the role of different arthropods and vertebrate species as competent reservoirs, and iii) the real disease burden for humans and animals. This review highlights the needs for further research and coordinated surveillance efforts on WNV in Africa.


Assuntos
Aedes/virologia , Culex/virologia , Carrapatos/virologia , Febre do Nilo Ocidental/epidemiologia , Febre do Nilo Ocidental/transmissão , África/epidemiologia , Animais , Humanos , Controle de Insetos/métodos , Mosquitos Vetores/virologia , Febre do Nilo Ocidental/patologia , Vírus do Nilo Ocidental/genética , Vírus do Nilo Ocidental/isolamento & purificação
20.
PLoS Negl Trop Dis ; 16(1): e0010084, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35015769

RESUMO

Dengue fever is one of the most severe viral diseases transmitted by Aedes mosquitoes, with traditional approaches of disease control proving insufficient to prevent significant disease burden. Release of Wolbachia-transinfected mosquitoes offers a promising alternative control methodologies; Wolbachia-transinfected female Aedes aegypti demonstrate reduced dengue virus transmission, whilst Wolbachia-transinfected males cause zygotic lethality when crossed with uninfected females, providing a method for suppressing mosquito populations. Although highly promising, the delicate nature of population control strategies and differences between local species populations means that controlled releases of Wolbachia-transinfected mosquitoes cannot be performed without extensive testing on specific local Ae. aegypti populations. In order to investigate the potential for using Wolbachia to suppress local Ae. aegypti populations in Taiwan, we performed lab-based and semi-field fitness trials. We first transinfected the Wolbachia strain wAlbB into a local Ae. aegypti population (wAlbB-Tw) and found no significant changes in lifespan, fecundity and fertility when compared to controls. In the laboratory, we found that as the proportion of released male mosquitoes carrying Wolbachia was increased, population suppression could reach up to 100%. Equivalent experiments in semi-field experiments found suppression rates of up to 70%. The release of different ratios of wAlbB-Tw males in the semi-field system provided an estimate of the optimal size of male releases. Our results indicate that wAlbB-Tw has significant potential for use in vector control strategies aimed at Ae. aegypti population suppression in Taiwan. Open field release trials are now necessary to confirm that wAlbB-Tw mediated suppression is feasible in natural environments.


Assuntos
Aedes/microbiologia , Dengue/prevenção & controle , Controle de Mosquitos/métodos , Controle Biológico de Vetores/métodos , Wolbachia/metabolismo , Animais , Agentes de Controle Biológico/administração & dosagem , Dengue/transmissão , Vírus da Dengue/isolamento & purificação , Feminino , Masculino , Mosquitos Vetores/virologia , Taiwan , Wolbachia/classificação , Zigoto/microbiologia
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