Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 8.827
Filtrar
2.
J Assoc Physicians India ; 67(7): 11-12, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31559760
3.
Acta Virol ; 63(3): 278-285, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31507193

RESUMO

Dengue virus (DENV) infection is one of the most widely-spread flavivirus infections with no effective antiviral drugs available. Peptide inhibitors have been considered as one of the best drug candidates due to their high specificity, selectivity in their interactions and minimum side effects. In this study, we employed computational studies using YASARA, HADDOCK server and PyMOL software to generate short and linear peptides based on a reference peptide, CP5-46A, to block DENV NS2B-NS3 protease. The inhibition potencies of the peptides were evaluated using in-house DENV2 serine protease and fluorogenic peptide substrates. In vitro analyses were performed to determine the peptides cytotoxicity and the inhibitory effects against DENV2 replication in WRL-68 cells. Our computational analyses revealed that the docking energy of AYA3, a 16 amino acid (aa) (-81.2 ± 10.6 kcal/mol) and AYA9, a 15 aa peptide (-83.8 ± 6.8 kcal/mol) to DENV NS2B-NS3 protease were much lower than the reference peptide (46 aa; -70.9 ± 7.8 kcal/mol) and the standard protease inhibitor, aprotinin (58 aa; -48.2 ± 10.6 kcal/mol). Both peptides showed significant inhibition against DENV2 NS2B-NS3 protease activity with IC50 values of 24 µM and 23 µM, respectively. AYA3 and AYA9 peptides also demonstrated approximately 68% and 83% of viral plaque reduction without significantly affecting cell viability at 50 µM concentration. In short, we generated short linear peptides with lower cytotoxic effect and substantial antiviral activities against DENV2. Further studies are required to investigate the inhibitory effects of these peptides in vivo. Keywords: peptide inhibitors; dengue virus; NS2B-NS3 protease; plaque reduction.


Assuntos
Antivirais , Vírus da Dengue , Peptídeos , Inibidores de Proteases , Replicação Viral , Antivirais/farmacologia , Biologia Computacional , Vírus da Dengue/enzimologia , Ativação Enzimática/efeitos dos fármacos , Humanos , Peptídeos/síntese química , Peptídeos/farmacologia , Inibidores de Proteases/farmacologia , Replicação Viral/efeitos dos fármacos
4.
Acta Virol ; 63(3): 292-300, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31507195

RESUMO

Dengue, considered the most important arthropod-borne viral disease affecting humans, is transmitted by the bite of mosquitoes of the genus Aedes and caused by one of the four distinct serotypes of dengue virus (DENV-1, -2, -3 and -4). Infection with one of the four serotypes provides lifelong homotypic immunity. However, immunity against the heterologous serotypes is transient. As a consequence, secondary infection may lead to severer manifestations due to cross-reactivity of antibodies and T-cells. Over 500,000 people are hospitalized every year and around 2,5 million, living in endemic areas, are at risk of infection. Given the background, the development of vaccines and anti-DENV drugs is of the utmost importance, as is the characterization of an animal model for testing them. The purpose of this study was to investigate ultrastructural alterations caused by DENV secondary infection in BALB/c mice heart. To achieve our goal, six BALB/c mice were infected with DENV-1 and, 4 months later, reinfected with DENV-2. Uninfected mice were used as negative controls. Heart samples were collected and processed for ultrastructural and histopathological analysis. Our results showed edema, endothelium activation characterized by the presence of transport vesicles, free platelets in interstitium, mitochondria presenting rarefied matrix and degenerated cristae, and disorganization of muscle fibers. These results point not only to BALB/c mice susceptibility to DENV infection, but also to the fact that, although it is not an often reported occurrence, dengue can lead to heart damage. Keywords: dengue; experimental model; reinfection; BALB/c mice.


Assuntos
Coinfecção , Vírus da Dengue , Dengue , Miocárdio , Animais , Dengue/patologia , Dengue/virologia , Modelos Animais de Doenças , Coração/virologia , Camundongos , Camundongos Endogâmicos BALB C , Miocárdio/patologia
6.
BMC Evol Biol ; 19(1): 163, 2019 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-31375065

RESUMO

BACKGROUND: Ancestral character states computed from the combination of phylogenetic trees with extrinsic traits are used to decipher evolutionary scenarios in various research fields such as phylogeography, epidemiology, and ecology. Despite the existence of powerful methods and software in ancestral character state inference, difficulties may arise when interpreting the outputs of such inferences. The growing complexity of data (trees, annotations), the diversity of optimization criteria for computing trees and ancestral character states, the combinatorial explosion of potential evolutionary scenarios if some ancestral characters states do not stand out clearly from others, requires the design of new methods to explore associations of phylogenetic trees with extrinsic traits, to ease the visualization and interpretation of evolutionary scenarios. RESULT: We developed PastView, a user-friendly interface that includes numerical and graphical features to help users to import and/or compute ancestral character states from discrete variables and extract ancestral scenarios as sets of successive transitions of character states from the tree root to its leaves. PastView provides summarized views such as transition maps and integrates comparative tools to highlight agreements or discrepancies between methods of ancestral annotations inference. CONCLUSION: The main contribution of PastView is to assemble known numerical and graphical methods into a multi-maps graphical user interface dedicated to the computing, searching and viewing of evolutionary scenarios based on phylogenetic trees and ancestral character states. PastView is available publicly as a standalone software on www.pastview.org .


Assuntos
Filogenia , Software , Interface Usuário-Computador , Albânia/epidemiologia , Dengue/epidemiologia , Vírus da Dengue/genética , Infecções por HIV/epidemiologia , HIV-1/genética , Humanos , Fenótipo , Filogeografia
7.
Arch Virol ; 164(11): 2789-2792, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31414286

RESUMO

Replication of the dengue virus (DENV) genome occurs in a vesicle in the endoplasmic reticulum by a complex of host and viral proteins. Two host proteins, STT3A and STT3B, as members of the oligosaccharyl transferase complex, have been implicated in playing structural roles in the vesicle in mammalian cells, and the absence of these proteins has been shown to decrease DENV replication. Aedes aegypti is the main vector of the virus and has been used previously as a model organism to study mosquito-virus interactions. In this study, we found that genes of the oligosaccharyl transferase complex have no effect on replication of DENV in mosquito cells.


Assuntos
Aedes/virologia , Vírus da Dengue/crescimento & desenvolvimento , Vírus da Dengue/genética , Hexosiltransferases/genética , Proteínas de Membrana/genética , Replicação Viral/genética , Animais , Benzamidas/farmacologia , Linhagem Celular , Cercopithecus aethiops , Dengue/virologia , Retículo Endoplasmático/virologia , Genoma Viral/genética , Glicosilação , Hexosiltransferases/antagonistas & inibidores , Interações Hospedeiro-Patógeno , Proteínas de Membrana/antagonistas & inibidores , RNA Viral/genética , Sulfonamidas/farmacologia , Células Vero
8.
Arch Virol ; 164(11): 2793-2797, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31440811

RESUMO

The DC-SIGN glycoprotein is responsible for the initial adhesion of dengue virus (DENV) to immune cells by the carbohydrate recognition domain (CRD). There are thirteen soluble and membrane-bound DC-SIGN isoforms, but the role of soluble isoforms in the DENV internalization process is not known. Five isoforms with an altered or absent CRD were identified, and three different soluble isoforms were used to confirm the interactions with mannose residues. The results show the loss of binding ability of one soluble isoform and binding ability of two of them. All of them will be used to verify their role in the DENV internalization process.


Assuntos
Moléculas de Adesão Celular/genética , Moléculas de Adesão Celular/metabolismo , Vírus da Dengue/metabolismo , Lectinas Tipo C/genética , Lectinas Tipo C/metabolismo , Manose/metabolismo , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Ligação Viral , Internalização do Vírus , Sequência de Aminoácidos , Sequência de Bases , Dengue/virologia , Vírus da Dengue/genética , Ligantes , Ligação Proteica/genética , Isoformas de Proteínas/genética
9.
BMC Infect Dis ; 19(1): 680, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31370795

RESUMO

BACKGROUND: A major challenge in dengue management in resource limited settings is the confirmation of diagnosis. Clinical features of dengue often overlap with other infections and molecular diagnostic tools are not readily accessible to clinicians at hospitals. In addition, the prediction of plasma leakage in dengue is also difficult. Hematocrit level and ultrasound scans (combined with clinical parameters) are helpful to detect plasma leakage once it has happened, not before. METHODS: Colombo Dengue Study (CDS) is a prospective cohort study of clinically suspected adult dengue patients recruited from the National hospital of Sri Lanka (within the first 3 days of fever) that aimed to a) identify clinical and basic laboratory test parameters to differentiate dengue from non-dengue fever, b) evaluate the comparative efficacy of loop-mediated isothermal amplification (LAMP) for dengue diagnosis (vs. NS1 antigen test and RT-qPCR) and c) identify early associations that are predictive of plasma leakage or severe dengue. The basic laboratory tests considered here included hematological parameters, serum biochemistry and inflammatory markers. RESULTS: Only 70% of clinically suspected patients were confirmed as having dengue by either the NS1 antigen test or RT-qPCR. On a Bayesian latent class model which assumes no "gold standard", LAMP performed equally or better than RT-qPCR and NS1 antigen test respectively. When confirmed dengue patients were compared with others, the earlier group had significantly lower lymphocyte counts and higher aspartate aminotransferase levels (AST) within the first 3 days of fever. Confirmed dengue patients with plasma leakage had a lower mean age and a higher median baseline AST level compared to those without plasma leakage (p < 0.05). CONCLUSION: Clinical suspicion overestimates the true number of dengue patients. RT-LAMP is a potentially useful low-cost diagnostic tool for dengue diagnosis. Confirmed dengue patients had significantly higher AST levels and lower lymphocyte counts in early disease compared to others. In confirmed dengue patients, younger age and a higher AST level in early infection were associated with subsequent plasma leakage.


Assuntos
Aspartato Aminotransferases/sangue , Técnicas de Amplificação de Ácido Nucleico/métodos , Dengue Grave/diagnóstico , Dengue Grave/etiologia , Adulto , Teorema de Bayes , Biomarcadores/sangue , Estudos de Coortes , Dengue/diagnóstico , Vírus da Dengue/genética , Feminino , Febre/virologia , Humanos , Testes Imunológicos , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Medição de Risco , Sensibilidade e Especificidade , Dengue Grave/sangue , Sri Lanka
10.
Mikrobiyol Bul ; 53(3): 348-353, 2019 Jul.
Artigo em Turco | MEDLINE | ID: mdl-31414637

RESUMO

The frequency of travel-related infections in the world has increased due to the easily and widespread use of travel facilities in the 21st century. Vector-borne diseases are an important part of infectious diseases. Dengue fever is one of the travel-related infections that has been reported increasingly in recent years through the development of diagnostic methods. The aim of this report was to present two Dengue fever cases originating from travel. There was a story of mosquito bite during a trip to Sri Lanka travel in our first case. The patient was 30 years old and maculopapular rash appeared on the fifth day of contact. Three days after the onset of the rash, she has admitted to our clinic, complaining with fever and chills. Increased leukopenia and muscle enzymes were detected in the laboratory analysis. Real-time reverse transcriptase polimerase chain reaction (RT-PCR) was positive in the serum sample. The patient was followed up with supportive care and discharged by improvement. The second case, a 24-year-old male, had a story of mosquito bite during his trip to Malaysia. After the patient complained of fever, chills, fever, nausea, vomiting and muscle pain, the Dengue virus (DENV) NS1 antigen test performed in this country was found to be positive. In the second case, there was no maculopapular rash and laboratory analysis showed an increase in leukopenia, thrombocytopenia and muscle enzymes. RT-PCR positivity was detected in the serum sample. The patient was followed up with supportive treatment and discharged with cure. DENV infections are caused by DENV which is common in the tropical areas of the world. There are four DENV-1, DENV-2, DENV-3 and DENV-4 serotypes. DENV infections can present different clinical manifestations such as asymptomatic disease, viral syndrome, Dengue haemorrhagic fever, and Dengue shock syndrome. Dengue fever is often accompanied by arthritis, maculopapular rash and high fever. Our cases were defined as Dengue fever according to this definition. In the diagnosis of the disease, it is necessary first to be suspicious of the disease and the travel history must be questioned. In the definitive diagnosis, virus isolation, antigen, nucleic acid detection and serological tests are used. The virus can be isolated from blood, serum, urine and tissues. In the first five days after beginning of the symptoms associated with DENV infections, serum RT-PCR and Dengue NS1 antigen test may be positive.


Assuntos
Vírus da Dengue , Dengue , Doença Relacionada a Viagens , Adulto , Dengue/complicações , Dengue/diagnóstico , Dengue/patologia , Dengue/virologia , Vírus da Dengue/classificação , Exantema/etiologia , Feminino , Humanos , Malásia , Masculino , Sri Lanka , Resultado do Tratamento , Adulto Jovem
11.
Rev Inst Med Trop Sao Paulo ; 61: e40, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31432989

RESUMO

Several arboviruses have emerged and/or re-emerged in North, Central and South-American countries. Viruses from some regions of Africa and Asia, such as the Zika and Chikungunya virus have been introduced in new continents causing major public health problems. The aim of this study was to investigate the presence of RNA from Zika, Dengue and Chikungunya viruses in symptomatic patients from Rondonia, where the epidemiological profile is still little known, by one-step real-time RT-PCR. The main clinical signs and symtoms were fever (51.2%), headache (78%), chills (6.1%), pruritus (12.2%), exanthema (20.1%), arthralgia (35.3%), myalgia (26.8%) and retro-orbital pain (19.5%). Serum from 164 symptomatic patients were collected and tested for RNA of Zika, Dengue types 1 to 4 and Chikungunya viruses, in addition to antibodies against Dengue NS1 antigen. Direct microscopy for Malaria was also performed. Only ZIKV RNA was detected in 4.3% of the patients, and in the remaining 95.7% of the patients RNA for Zika, Dengue and Chikungunya viruses were not detected. This finding is intriguing as the region has been endemic for Dengue for a long time and more recently for Chikungunya virus as well. The results indicated that medical and molecular parameters obtained were suitable to describe the first report of symptomatic Zika infections in this region. Furthermore, the low rate of detection, compared to clinical signs and symptoms as the solely diagnosis criteria, suggests that molecular assays for detection of viruses or other pathogens that cause similar symptoms should be used and the corresponding diseases could be included in the compulsory notification list.


Assuntos
Febre de Chikungunya/epidemiologia , Vírus Chikungunya/genética , Vírus da Dengue/genética , Dengue/epidemiologia , Infecção por Zika virus/epidemiologia , Zika virus/genética , Brasil/epidemiologia , Febre de Chikungunya/diagnóstico , Dengue/diagnóstico , Humanos , Vírus de RNA/genética , Reação em Cadeia da Polimerase em Tempo Real , Infecção por Zika virus/diagnóstico
12.
Mem Inst Oswaldo Cruz ; 114: e190098, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31411310

RESUMO

BACKGROUND: Dengue virus (DENV) has circulated in Brazil for over 30 years. During this time, one serotype has cyclically replaced the other, until recently, when all four distinct serotypes began to circulate together. Persistent circulation of DENV for long time periods makes sequential infections throughout a person's life possible. After primary DENV infection, life-long immunity is developed for the infecting serotype. Since DENV and Zika virus (ZIKV) are antigenically similar, the possibility of cross-reactions has attracted attention and has been demonstrated in vitro. OBJECTIVE: The aim of this study was to investigate whether immune-sera from DENV and ZIKV infected patients would cross-react in vitro with other Flaviviridae family members. METHODS: Cross-reaction of the studied samples with yellow fever virus (YFV), West Nile virus (WNV), Rocio virus (ROCV), Saint Louis virus (SLEV) and Ilheus virus (ILHV) has been investigated by plaque reduction neutralisation test (PRNT) and the antibody-dependent enhancement (ADE) by flow-cytometry. FINDINGS: Antibodies against ZIKV and DENV virus cross-reacted with other flaviviruses either neutralising or enhancing the infection. Thus, viral entrance into FcRFcɣRII-expressing cells were influenced by the cross-reactive antibodies. ZIKV or DENV immune sera enhanced cellular infection by WNV, ILHV, ROCV and SLEV. Finally, DENV immune sera presented higher neutralising activity for YFV and SLEV. While ZIKV immune sera neutralised WNV, ILHV and ROCV with high frequencies of positivity. MAIN CONCLUSIONS: The co-circulation of those viruses in the same area represents a risk for the development of severe infections if they spread throughout the country. Successive flavivirus infections may have an impact on disease pathogenesis, as well as on the development of safe vaccine strategies.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Vírus da Dengue/imunologia , Zika virus/imunologia , Reações Cruzadas/imunologia , Flavivirus/classificação , Flavivirus/imunologia , Citometria de Fluxo , Humanos , Testes de Neutralização
13.
An Acad Bras Cienc ; 91(suppl 3): e20190407, 2019 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-31460596

RESUMO

We review the potential of Amazon forest as a source for circulation and maintenance of native arboviruses as well its capacity to host exotic arboviruses introduced in Brazil during their process of adapting to the Amazon environment. After a brief introduction about arboviruses isolated in Amazon region and description of the main arboviruses pathogenic to humans, we highlight the history of the last two exotic viruses introduced in Brazil - Chikungunya virus (CHIKV) and Zika virus (ZIKV) - and their consequences to the public health. Finally, we discuss and hypothesize what will happen with them after the outbreak. We look to the past to predict the future.


Assuntos
Arbovirus/classificação , Doenças Transmissíveis Emergentes/virologia , Animais , Brasil , Vírus Chikungunya , Vírus da Dengue , Humanos , Orthobunyavirus , Vírus da Febre Amarela , Zika virus
14.
J Assoc Physicians India ; 67(4): 39-42, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31299837

RESUMO

Background: Dengue viral infection is common worldwide. Recent studies have shown dengue viral infection causing encephalopathy, with high morbidity and mortality. Dengue encephalopathy patients usually present with altered sensorium, elevated lab parameters and high antibody titres at the time of admission. Dengue infection was very common and virulent in Hadoti region during August to November 2017 and many patients presented with encephalopathy. Aims: To study the clinical presentation, lab parameters and other diagnostic features, management and outcome of patients of dengue fever with encephalopathy in Hadoti region in August to November 2017. Settings and Design: The study was done in Govt Medical college Hospital Kota and other multi-speciality hospitals of Kota. Study population comprised of 60 patients presenting with febrile illness and thrombocytopenia, serologically proved to be having Dengue fever. Among these 60 patients, 30 patients had encephalopathy who presented with altered sensorium, seizures or any other neurological symptoms and remaining 30 had no signs and symptoms of encephalopathy. Results: Among 30 patients with encephalopathy and positive serology (NS1/IgM/ IgG), fever and altered sensorium was most common symptom, while amongst patients without encephalopathy fever with chills and generalised bodyache was more common clinical feature. Convulsions and respiratory distress were very common among encephalopathy patients. Out of 30 encephalopathy patients 16 patients (53%) had convulsions, 14 (46%) had respiratory distress, 17(56%) had shock and 3 patients (10%) had hemiplegia. 2 patients also had visual blurring and dysarthria. Mean duration between appearance of fever and altered sensorium was 4.6 (±2.1) days. Most of patients with encephalopathy had deranged hepatic (bilirubin, SGOT, SGPT), renal (urea, creatinine, decreased urine output) and coagulation parameters (PT/INR, bleeding manifestations). 9 (30%) patients died and 21(70%) patients improved with complete recovery (except 3 hemiplegic patients). Conclusion: Increased incidence of dengue fever with encephalopathy in the recent years, in the absence of single sensitive test for detecting dengue encephalopathy, variable CSF and MRI Brain features, and associated high morbidity and mortality poses a big problem for clinician. This study may be helpful in focussing on early diagnosis and aggressive initial management which can influence final outcome.


Assuntos
Encefalopatias/diagnóstico , Dengue/diagnóstico , Encefalopatias/terapia , Dengue/terapia , Vírus da Dengue , Febre , Humanos , Índia , Convulsões
15.
J Assoc Physicians India ; 67(4): 82-84, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31299849

RESUMO

Dengue virus induced encephalitis is a very rare entity and its full clinicoradiological profile is still unknown. We here report two cases of dengue encephalitis from Eastern India. The first one is a 20 year old female and the second one is a 13 year old boy. Both of them presented with altered consciousness and seizures. Blood and CSF study for dengue IgM were positive. MRI of brain showed T2 hyperintensity in the Thalami along with similar changes in other parts of the brain. Both patients responded to conservative therapy but residual neurological deficit were variably present. Relevant literature pertaining to dengue encephalitis have also been discussed.


Assuntos
Vírus da Dengue , Dengue/diagnóstico , Encefalite Japonesa/diagnóstico , Adolescente , Adulto , Encéfalo , Feminino , Humanos , Índia , Masculino , Adulto Jovem
16.
Ecol Lett ; 22(10): 1690-1708, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31286630

RESUMO

Mosquito-borne diseases cause a major burden of disease worldwide. The vital rates of these ectothermic vectors and parasites respond strongly and nonlinearly to temperature and therefore to climate change. Here, we review how trait-based approaches can synthesise and mechanistically predict the temperature dependence of transmission across vectors, pathogens, and environments. We present 11 pathogens transmitted by 15 different mosquito species - including globally important diseases like malaria, dengue, and Zika - synthesised from previously published studies. Transmission varied strongly and unimodally with temperature, peaking at 23-29ºC and declining to zero below 9-23ºC and above 32-38ºC. Different traits restricted transmission at low versus high temperatures, and temperature effects on transmission varied by both mosquito and parasite species. Temperate pathogens exhibit broader thermal ranges and cooler thermal minima and optima than tropical pathogens. Among tropical pathogens, malaria and Ross River virus had lower thermal optima (25-26ºC) while dengue and Zika viruses had the highest (29ºC) thermal optima. We expect warming to increase transmission below thermal optima but decrease transmission above optima. Key directions for future work include linking mechanistic models to field transmission, combining temperature effects with control measures, incorporating trait variation and temperature variation, and investigating climate adaptation and migration.


Assuntos
Aedes/parasitologia , Aedes/virologia , Temperatura Ambiente , Animais , Mudança Climática , Vírus da Dengue , Malária/transmissão , Mosquitos Vetores/parasitologia , Mosquitos Vetores/virologia , Plasmodium , Vírus do Rio Ross , Viroses/transmissão , Zika virus
17.
BMC Infect Dis ; 19(1): 580, 2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31272403

RESUMO

BACKGROUND: Transcriptomic profiling has generated extensive lists of genes that respond to viral infection in mosquitoes. These gene lists contain two types of genes; (1) those that are responsible for the insect's natural antiviral defense mechanisms, including some known innate immunity genes, and (2) genes whose change in expression may occur simply as a result of infection. As genetic modification tools for mosquitoes continue to improve, the opportunities to make refractory insects via allelic replacement or delivery of small RNAs that alter gene expression are expanding. Therefore, the ability to identify which genes in transcriptional profiles may have immune function has increasing value. Arboviruses encounter a range of mosquito tissues and physiologies as they traverse from the midgut to the salivary glands. While the midgut is well-studied as the primary tissue barrier, antiviral genes expressed in the subsequent tissues of the carcass offer additional candidates for second stage intervention in the mosquito body. METHODS: Mosquito lines collected recently from field populations exhibit natural genetic variation for dengue virus susceptibility. We sought to use a modified full-sib breeding design to identify mosquito families that varied in their dengue viral load in their bodies post infection. RESULTS: By delivering virus intrathoracically, we bypassed the midgut and focused on whole body responses in order to evaluate carcass-associated refractoriness. We tested 25 candidate genes selected for their appearance in multiple published transcriptional profiles and were able to identify 12 whose expression varied with susceptibility in the genetic families. CONCLUSIONS: This method, using natural genetic variation, offers a simple means to screen and reduce candidate gene lists prior to carrying out more labor-intensive functional studies. The extracted RNA from the females across the families represents a storable resource that can be used to screen subsequent candidate genes in the future. The aspect of vector competence being assessed could be varied by focusing on different tissues or time points post infection.


Assuntos
Aedes/virologia , Vírus da Dengue/genética , Dengue/virologia , Variação Genética , Imunidade Inata/genética , Mosquitos Vetores/virologia , Animais , Vírus da Dengue/isolamento & purificação , Feminino , Perfilação da Expressão Gênica , Masculino , Carga Viral
18.
BMC Public Health ; 19(1): 987, 2019 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-31337359

RESUMO

BACKGROUND: The Gulf Coast of the United States is home to mosquito vectors that may spread disease causing pathogens, and environmental conditions that are ideal for the sustained transmission of mosquito-borne pathogens. Understanding public perceptions of mosquito-borne diseases and mosquito prevention strategies is critical for the development of effective vector control strategies and public health interventions. Here, we present a survey conducted in Mobile, Alabama along the Gulf Coast to better understand public perceptions of mosquito-borne diseases, mosquito control activities, and potential risk factors. METHODS: Using Knowledge, Attitude, and Practice (KAPs) assessments, we surveyed populations living in 12 zip codes in Mobile, Alabama using a 7-point Likert scale and frequency assessments. Survey participants were asked about vector control efforts, knowledge of mosquito-borne diseases, and understanding of mosquito ecology and breeding habitats. RESULTS: One hundred twenty-six surveys were completed in Mobile, Alabama, revealing that 73% of participants reported being bitten by a mosquito in the last 30 days and mosquitoes were frequently seen in their homes. Ninety-four percent of respondents had heard of Zika Virus at the time of the survey, and respondents reported being least familiar with dengue virus and chikungunya virus. CONCLUSIONS: Chikungunya virus, dengue virus, malaria, West Nile virus, and Zika virus have been documented in the Gulf Coast of the United States. The mosquitoes which vector all of these diseases are presently in the Gulf Coast meaning all five diseases pose a potential risk to human health. The results of this survey emphasize knowledge gaps that public health officials can address to empower the population to reduce their risk of these mosquito-borne diseases. Each species of mosquito has specific preferences for breeding and feeding and there is no one size fits all prevention approach, educating people on the need for a variety of approaches in order to address all species will further empower them to control mosquitoes where they live and further reduce their risk of disease.


Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Controle de Mosquitos/métodos , Mosquitos Vetores , Alabama , Vírus Chikungunya , Vírus da Dengue , Humanos , Malária/prevenção & controle , Saúde Pública , Fatores de Risco , Inquéritos e Questionários , Vírus do Nilo Ocidental , Zika virus
19.
BMC Public Health ; 19(1): 958, 2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31319834

RESUMO

BACKGROUND: Dengue fever is the world's fastest spreading mosquito borne viral infection. It is prevalent throughout both subtropical and tropical region, and affects over 128 countries. Dengue virus (DENV) infection poses a serious global public health challenge to three billion people, resulting in approximately 200 million cases of morbidity and 50,000 cases of mortality annually. In Cameroon like in most sub-Saharan African countries, DENV infection occur concurrently with other infectious diseases whose symptoms often overlap, rendering differential diagnosis challenging. This study aims at determining the frequency of acute dengue among febrile children under 15 years attending hospitals in some areas of Cameroon. METHODS: A total of 961 children under the age of 15 were recruited in a cross-sectional study using systematic sampling technique and by selecting each subject out of the three. The study was conducted in 10 public health centers in Cameroon. Demographic data and risk factors of the subjects were obtained using well-structured questionnaires. Dengue virus NS1 antigen, IgM and IgG were analysed using a Tell me fast® Combo Dengue NS1-IgG/IgM Rapid Test. An in-house ELISA test for dengue specific IgM antibody was equally performed for confirmation. Descriptive statistical analysis was performed using Graph pad version 6.0. RESULTS: A prevalence of 6.14% acute dengue virus infection was observed among children with febrile illness with a significant difference (p = 0.0488) between males (4.7%) and females (7.7%). In addition, children who reportedly were unprotected from vectors, showed a comparatively higher prevalence of the disease seropositivity than those practicing protective measures. CONCLUSION: DENV infection therefore is an important cause of fever among children in Cameroon. Thus, there is a need to include differential screening for DENV infections as a tool in the management of fever in children in the country.


Assuntos
Instituições de Assistência Ambulatorial/estatística & dados numéricos , Vírus da Dengue , Dengue/epidemiologia , Febre/epidemiologia , Pediatria/estatística & dados numéricos , Adolescente , Anticorpos Antivirais/análise , Anticorpos Antivirais/imunologia , Camarões/epidemiologia , Criança , Pré-Escolar , Estudos Transversais , Dengue/virologia , Vírus da Dengue/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Febre/virologia , Humanos , Imunoglobulina M/análise , Imunoglobulina M/imunologia , Masculino , Prevalência , Fatores de Risco
20.
Nat Commun ; 10(1): 2402, 2019 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-31160588

RESUMO

Platelet-leukocyte interactions amplify inflammatory reactions, but the underlying mechanism is still unclear. CLEC5A and CLEC2 are spleen tyrosine kinase (Syk)-coupled C-type lectin receptors, abundantly expressed by leukocytes and platelets, respectively. Whereas CLEC5A is a pattern recognition receptor (PRR) to flaviviruses and bacteria, CLEC2 is the receptor for platelet-activating snake venom aggretin. Here we show that dengue virus (DV) activates platelets via CLEC2 to release extracellular vesicles (EVs), including exosomes (EXOs) and microvesicles (MVs). DV-induced EXOs (DV-EXOs) and MVs (DV-MVs) further activate CLEC5A and TLR2 on neutrophils and macrophages, thereby induce neutrophil extracellular trap (NET) formation and proinflammatory cytokine release. Compared to  stat1-/- mice, simultaneous blockade of CLEC5A and TLR2 effectively attenuates DV-induced inflammatory response and increases survival rate from 30 to 90%. The identification of critical roles of CLEC2 and CLEC5A/TLR2 in platelet-leukocyte interactions will support the development of novel strategies to treat acute viral infection in the future.


Assuntos
Plaquetas/metabolismo , Vírus da Dengue/imunologia , Dengue/imunologia , Vesículas Extracelulares/imunologia , Lectinas Tipo C/imunologia , Macrófagos/imunologia , Neutrófilos/imunologia , Receptores de Superfície Celular/imunologia , Receptor 2 Toll-Like/imunologia , Animais , Micropartículas Derivadas de Células/imunologia , Micropartículas Derivadas de Células/metabolismo , Citocinas/imunologia , Dengue/virologia , Exossomos/imunologia , Exossomos/metabolismo , Armadilhas Extracelulares/imunologia , Vesículas Extracelulares/metabolismo , Humanos , Inflamação , Lectinas Tipo C/genética , Camundongos , Camundongos Knockout , Ativação Plaquetária , Receptores de Superfície Celular/genética , Fator de Transcrição STAT1/genética , Taxa de Sobrevida
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA