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1.
Artigo em Inglês | MEDLINE | ID: mdl-34574555

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19). Real-time RT-PCR is the most commonly used method for COVID-19 diagnosis. However, serological assays are urgently needed as complementary tools to RT-PCR. Hachim et al. 2020 and Burbelo et al. 2020 demonstrated that anti-nucleocapsid(N) SARS-CoV-2 antibodies are higher and appear earlier than the spike antibodies. Additionally, cross-reactive antibodies against N protein are more prevalent than those against spike protein. We developed a less cross-reactive immunoglobulin G (IgG) indirect ELISA by using a truncated recombinant SARS-CoV-2 N protein as assay antigen. A highly conserved region of coronaviruses N protein was deleted and the protein was prepared using an E. coli protein expression system. A total of 177 samples collected from COVID-19 suspected cases and 155 negative control sera collected during the pre-COVID-19 period were applied to evaluate the assay's performance, with the plaque reduction neutralization test and the commercial SARS-CoV-2 spike protein IgG ELISA as gold standards. The SARS-CoV-2 N truncated protein-based ELISA showed similar sensitivity (91.1% vs. 91.9%) and specificity (93.8% vs. 93.8%) between the PRNT and spike IgG ELISA, as well as also higher specificity compared to the full-length N protein (93.8% vs. 89.9%). Our ELISA can be used for the diagnosis and surveillance of COVID-19.


Assuntos
COVID-19 , Proteínas do Nucleocapsídeo , Anticorpos Antivirais , Teste para COVID-19 , Ensaio de Imunoadsorção Enzimática , Escherichia coli , Humanos , Imunoglobulina G , Proteínas do Nucleocapsídeo/genética , SARS-CoV-2 , Sensibilidade e Especificidade , Glicoproteína da Espícula de Coronavírus
2.
Viruses ; 13(8)2021 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-34452310

RESUMO

Dengue virus (DENV) is one of the most prevalent neglected tropical diseases, with half of the world's population at risk of infection. In Nepal, DENV was first reported in 2004, and its prevalence is increasing every year. The present study aimed to obtain and characterize the full-length genome sequence of DENV from the 2017 outbreak. Hospital-based surveillance was conducted in two provinces of Nepal during the outbreak. Acute-phase serum samples were collected from 141 clinically suspected dengue patients after the rainy season. By serological and molecular techniques, 37 (26.9%) and 49 (34.8%), respectively, were confirmed as dengue patients. The cosmopolitan genotype of DENV-2 was isolated from 27 laboratory-confirmed dengue patients. Genomic analysis showed many amino acid substitutions distributed mainly among the E, NS3, and NS5 genes. Phylogenetic analyses of the whole genome sequence revealed two clades (Asian and Indian) among DENV-2 isolates from Nepal. The DENV isolates from hilly and Terai areas were similar to Asian and Indian strains, respectively. Further genomic study on different DENV serotypes is warranted to understand DENV epidemics in Nepal, where there are limited scientific resources and infrastructure.

3.
J Infect Chemother ; 27(10): 1525-1528, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34294531

RESUMO

Polymerase chain reaction (PCR) testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is necessary for confirming a diagnosis of Coronavirus disease 2019 (COVID-19). Here we present a COVID-19 case of an elderly woman whose SARS-CoV-2 PCR tests showed false negative repeatedly by evaluating with different sampling sites and procedures. Nasopharyngeal swabs, suctioned sputum, and tongue swabs were collected for SARS-CoV-2-PCR. As for tongue swabs, we compared between two different sample conditions; one obtained with dry condition and the other obtained with moistened condition inside the oral cavity. SARS-CoV-2-PCR showed positive for an extended period with suctioned sputum samples compared with nasopharyngeal swabs and tongue swabs. No SARS-CoV-2 from a nasopharyngeal swab sample obtained on day 46 after symptoms onset was isolated despite high viral load (183740.5 copies/5µL). An adequate production of neutralizing antibody in a serum sample on day 46 was also confirmed. The number of RNA copies of the tongue swab samples was higher with moistened condition than with dry condition. The present case suggests that the difference of sampling site or sample condition can affect PCR results. High loads viral RNA detection does not always correlate with infectivity.


Assuntos
COVID-19 , SARS-CoV-2 , Idoso , Feminino , Humanos , Nasofaringe , Reação em Cadeia da Polimerase , RNA Viral , Manejo de Espécimes
4.
Viruses ; 13(7)2021 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-34202565

RESUMO

Arenaviruses and coronaviruses include several human pathogenic viruses, such as Lassa virus, Lymphocytic choriomeningitis virus (LCMV), SARS-CoV, MERS-CoV, and SARS-CoV-2. Although these viruses belong to different virus families, they possess a common motif, the DED/EDh motif, known as an exonuclease (ExoN) motif. In this study, proof-of-concept studies, in which the DED/EDh motif in these viral proteins, NP for arenaviruses, and nsp14 for coronaviruses, could be a drug target, were performed. Docking simulation studies between two structurally different chemical compounds, ATA and PV6R, and the DED/EDh motifs in these viral proteins indicated that these compounds target DED/EDh motifs. The concentration which exhibited modest cell toxicity was used with these compounds to treat LCMV and SARS-CoV-2 infections in two different cell lines, A549 and Vero 76 cells. Both ATA and PV6R inhibited the post-entry step of LCMV and SARS-CoV-2 infection. These studies strongly suggest that DED/EDh motifs in these viral proteins could be a drug target to combat two distinct viral families, arenaviruses and coronaviruses.


Assuntos
Antivirais/farmacologia , Exorribonucleases/antagonistas & inibidores , Vírus da Coriomeningite Linfocítica/efeitos dos fármacos , SARS-CoV-2/efeitos dos fármacos , Proteínas não Estruturais Virais/antagonistas & inibidores , Proteínas Virais/antagonistas & inibidores , Replicação Viral/efeitos dos fármacos , Células A549 , Motivos de Aminoácidos , Animais , Chlorocebus aethiops , Descoberta de Drogas , Humanos , Simulação de Acoplamento Molecular , Células Vero
5.
Viruses ; 13(6)2021 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-34208667

RESUMO

Dengue fever, caused by the mosquito-borne dengue virus (DENV), has been endemic in Myanmar since 1970 and it has become a significant public health burden. It is crucial that circulating DENV strains are identified and monitored, and that their transmission efficiency and association with disease severity is understood. In this study, we analyzed DENV-1, DENV-2, DENV-3, and DENV-4 serotypes in 1235 serum samples collected in Myanmar between 2017 and 2019. Whole-genome sequencing of DENV-1-4 demonstrated that most DENV-1-4 strains had been circulating in Myanmar for several years. We also identified the emergence of DENV-3 genotype-I in 2017 samples, which persisted through 2018 and 2019. The emergence of the strain coincided with a period of increased DENV-3 cases and marked changes in the serotype dynamics. Nevertheless, we detected no significant differences between serum viral loads, disease severity, and infection status of individuals infected with different DENV serotypes during the 3-year study. Our results not only identify the spread of a new DENV-3 genotype into Yangon, Myanmar, but also support the importance of DENV evolution in changing the epidemic dynamics in endemic regions.


Assuntos
Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/virologia , Vírus da Dengue/classificação , Vírus da Dengue/genética , Dengue/epidemiologia , Dengue/virologia , Genótipo , Adolescente , Substituição de Aminoácidos , Criança , Pré-Escolar , Dengue/diagnóstico , Dengue/história , Vírus da Dengue/isolamento & purificação , Surtos de Doenças , Variação Genética , Genoma Viral , História do Século XXI , Humanos , Mianmar , Filogenia , Estudos Soroepidemiológicos , Sorogrupo , Sequenciamento Completo do Genoma
6.
Antiviral Res ; 192: 105121, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34175321

RESUMO

Zika virus (ZIKV) is a re-emerging mosquito-borne flavivirus of African origin that is transmitted by Aedes mosquitoes. ZIKV was historically limited to Africa and Asia, where mild cases were reported. However, ZIKV has recently been responsible for major global outbreaks associated with a wide range of neurological complications. Since no antiviral therapy exists for ZIKV, drug discovery research for ZIKV is crucial. Intracellular lipids regulated by sterol regulatory element-binding proteins (SREBPs) are important in flavivirus pathogenesis. PF-429242 has been reported to inhibit the activity of site-1 protease (S1P), which regulates the expression of SREBP target genes. Our primary objective in this study is to elucidate the mechanism of the antiviral activity of PF-429242 against the African genotype (ZIKVMR-766) and Asian genotypes (ZIKV H/PF 2013 and ZIKV PRVABC59) using several primate-derived cell lines. The virus titer was determined via a focus-forming assay; we used flow cytometry to quantify intracellular lipids in ZIKV-infected and mock-treated cells. The PF-429242 molecule effectively suppressed ZIKV infection in neuronal cell lines; T98G, U-87MG, SK-N-SH and primary monocytes cell, indicating that PF-429242 molecule can be used therapeutically. A strong reduction in ZIKV replication was observed at 12 µM and 30 µM in in neuronal cell lines and primary monocytes, respectively. Interestingly, the inhibitory effects of the PF-429242 molecule were observed when it was tested on various ZIKV-lineage infections. Lipid quantification reveals that ZIKV increases lipogenesis in infected cells, while the exogenous addition of cholesterol effectively blocks ZIKV replication. Furthermore, the supplementation of oleic acid increases the ZIKV titer. Fenofibrate, an inhibitor of lipid droplet formation, reduces the ZIKV titer. Collectively, our results demonstrate that the development of antiviral drugs against ZIKV could be based on key regulators of lipid metabolism. In addition, this study reveals that the mechanism of the PF-429242-mediated suppression among flavivirus infections is not entirely identical. Our results warrant further evaluation of PF-429242 as a prospective antiviral drug, given the multiple advantageous properties of this compound, such as its limited toxicity, neuroprotective properties, and broad spectrum of capabilities.

7.
PLoS One ; 16(6): e0251314, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34086703

RESUMO

BACKGROUND: Dengue (DEN) is a neglected tropical disease, and surveillance of dengue virus (DENV) serotypes and genotypes is critical for the early detection of outbreaks. Risk factors for outbreaks include the emergence of new genotypes and serotype shifting. METHODOLOGY AND PRINCIPAL FINDINGS: To understand the genomic and viral characteristics of DENV-infected patients, we conducted a cross-sectional descriptive study among pediatric patients admitted at the 550-bedded Mandalay Children Hospital during the 2018 DEN endemic season. We conducted virus isolation, serological tests, viremia level measurement, and whole-genome sequencing. Among the 202 serum samples, we detected 85 samples with DENV (46 DENV-1, 10 DENV-3, 26 DENV-4 and three multiple serotype co-infections) via reverse transcription quantitative/real-time PCR (RT-qPCR), and we obtained 49 DENV isolates (31 DENV-1, 10 DENV-3 and 8 DEN-4). We did not detect DENV-2 in this study. The viral genome levels in serum did not differ significantly among virus serotypes, infection status (primary versus secondary) and disease severity. Based on the phylogenetic analysis, we identified DENV-1 genotype-1, DENV-4 genotype-1 and DENV-3 genotype-3 and genotype-1 which was detected for the first time. Next-generation sequencing analysis revealed greater frequencies of nonsynonymous and synonymous mutations per gene in the nonstructural genes. Moreover, mutation rates were also higher among DENV-1. CONCLUSION/SIGNIFICANCE: In conclusion, there was an increasing trend of DENV-3 cases during DENV endemic season in 2018 with the first detection of the genotype 1. However, DENV-1 has remained the predominant serotype in this study area since 2013, and we identified stop codon mutations in the DENV-1 genome. This report is the first to feature a complete genome analysis of the strains of DENV-3 and DENV-4 circulating among pediatric patients in Myanmar. This study highlighted the importance of annual surveillance for a better understanding of the molecular epidemiology of DENVs.

8.
Jpn J Infect Dis ; 74(5): 443-449, 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-33642435

RESUMO

During the 2017 outbreak of severe dengue in Sri Lanka, dengue virus (DENV) serotypes 2, 3, and 4 were found to be co-circulating. Our previous study of 295 patients from the National Hospital Kandy in Sri Lanka between March 2017 and January 2018 determined that the dominant infecting serotype was DENV-2. In this study, we aimed to characterize the DENV-3 strains from non-severe and severe dengue patients from our previous study population. Patients' clinical records and previous laboratory tests, including dengue-specific nonstructural protein 1 antigen rapid test and IgM-capture and IgG enzyme-linked immunosorbent assays, were analyzed together with the present results of real-time reverse transcription polymerase chain reaction and next-generation sequencing of DENV-3. Complete genome analysis determined that DENV-3 isolates belonged to 2 different clades of genotype I and were genetically close to strains from Indonesia, China, Singapore, Malaysia, and Australia. There were 16 amino acid changes among DENV-3 isolates, and a greater number of changes were found in nonstructural proteins than in structural proteins. The emergence of DENV-3 genotype I was noted for the first time in Sri Lanka. Continuous monitoring of this newly emerged genotype and other DENV serotypes and genotypes is needed to determine their effects on future outbreaks and understand the molecular epidemiology of dengue.

9.
Biochem Biophys Res Commun ; 545: 203-207, 2021 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-33571909

RESUMO

The current COVID-19 pandemic requires urgent development of effective therapeutics. 5-amino levulinic acid (5-ALA) is a naturally synthesized amino acid and has been used for multiple purposes including as an anticancer therapy and as a dietary supplement due to its high bioavailability. In this study, we demonstrated that 5-ALA treatment potently inhibited infection of SARS-CoV-2, a causative agent of COVID-19, in cell culture. The antiviral effects could be detected in both human and non-human cells, without significant cytotoxicity. Therefore, 5-ALA is worth to be further investigated as an antiviral drug candidate for COVID-19.


Assuntos
Antivirais/farmacologia , COVID-19/tratamento farmacológico , Ácidos Levulínicos/farmacologia , Animais , Antivirais/administração & dosagem , COVID-19/prevenção & controle , COVID-19/virologia , Células CACO-2 , Chlorocebus aethiops , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos/métodos , Compostos Ferrosos/farmacologia , Humanos , Ácidos Levulínicos/administração & dosagem , Células Vero
10.
Trans R Soc Trop Med Hyg ; 115(6): 619-626, 2021 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32987406

RESUMO

BACKGROUND: Dengue cases have been continuously reported in Nepal, including some large outbreaks, since its first introduction in 2004. The disease is now expanding towards newer locations above 1400 m high, especially the country's capital city, Kathmandu. In 2019, >14,000 dengue cases including six deaths were reported. This study was aimed at the detection and molecular characterization of dengue virus (DENV) in dengue patients. METHODS: A total of 451 patients were enrolled in this study. Demographic, clinical and laboratory information was collected from dengue patients. Dengue infection was confirmed by antibody/antigen detection assays followed by RT-PCR analysis. RESULTS: The DENV patients showed fever, body ache, headache, myalgia, retro-orbital pain and arthralgia. The platelets were decreased, serum liver enzymes were increased and leucopenia was seen. Out of 195 patients, 111 (57.0%) were positive for DENV RNA by consensus PCR. We found DENV-2, 70 (63.1%) as the predominant serotype responsible for the 2019 outbreak, while DENV-3 was detected in two patients. CONCLUSION: Our findings suggest that DENV-2 was the major serotype causing the 2019 massive outbreak in Nepal. This information will help in disease control programs to understand the molecular epidemiology and its changing trend.


Assuntos
Vírus da Dengue , Dengue , Dengue/epidemiologia , Vírus da Dengue/genética , Surtos de Doenças , Humanos , Nepal/epidemiologia , Sorogrupo
11.
Am J Trop Med Hyg ; 103(5): 2059-2064, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32815502

RESUMO

To detect congenital ZIKV infection (CZI) in a birth cohort and among high-risk neonates in Vietnam, we collected umbilical cord blood plasma samples of newly delivered babies and peripheral plasma samples of high-risk neonates in Nha Trang, central Vietnam, between July 2017 and September 2018. Samples were subjected to serological and molecular tests. Of the 2013 newly delivered babies, 21 (1%) were positive for Zika virus (ZIKV) IgM and 1,599 (79%) for Flavivirus IgG. Among the 21 ZIKV IgM-positives, 11 were confirmed to have CZI because their plasma samples had anti-ZIKV neutralization titers ≥ 4 times higher than those against dengue virus (DENV)-1 to 4 and Japanese encephalitis virus (JEV) and were tested for the ZIKV RNA positive by real-time reverse transcription-PCR. Therefore, the incidence of CZI in our birth cohort was approximately 0.5%. Of the 150 high-risk neonates, three (2%) and 95 (63%) were positive for ZIKV IgM and Flavivirus IgG antibodies, respectively. None of the three ZIKV IgM-positives had ≥ 4 times higher anti-ZIKV neutralization titers than those against DENV-1 to 4 and JEV, and were therefore considered as probable CZI. Our results indicate that CZI is not rare in Vietnam. Although those with confirmed CZI did not show apparent symptoms suspected of congenital Zika syndrome at birth, detailed examinations and follow-up studies are needed to clarify the CZI impact in Vietnam. This is the first report of CZI cases in a birth cohort in Asia.


Assuntos
Infecção por Zika virus/congênito , Infecção por Zika virus/epidemiologia , Animais , Chlorocebus aethiops , Estudos de Coortes , Ensaio de Imunoadsorção Enzimática/métodos , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Recém-Nascido , Transmissão Vertical de Doenças Infecciosas , Masculino , Células Vero , Vietnã/epidemiologia
12.
PLoS One ; 15(6): e0234508, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32555732

RESUMO

Dengue virus (DENV) infection remains a major public health concern in many parts of the world, including Southeast Asia and the Americas. Sri Lanka experienced its largest dengue outbreak in 2017. Neurological symptoms associated with DENV infection have increasingly been reported in both children and adults. Here, we characterize DENV type 2 (DENV-2) strains, which were isolated from cerebrospinal fluid (CSF) and/or serum of patients with dengue encephalitis. Acute serum and CSF samples from each patient were subjected to dengue-specific non-structural protein 1 (NS1) antigen test, IgM and IgG enzyme-linked immunosorbent assay (ELISA), virus isolation, conventional and real-time polymerase chain reaction (PCR), and next-generation sequencing (NGS). Among the 5 dengue encephalitis patients examined, 4 recovered and 1 died. DENV-2 strains were isolated from serum and/or CSF samples of 3 patients. The highest viral genome levels were detected in the CSF and serum of the patient who succumbed to the illness. A phylogenetic tree revealed that the DENV-2 isolates belonged to a new clade of cosmopolitan genotype and were genetically close to strains identified in China, South Korea, Singapore, Malaysia, Thailand, and the Philippines. According to the NGS analysis, greater frequencies of nonsynonymous and synonymous mutations per gene were identified in the nonstructural genes. The full genomes of serum- and CSF-derived DENV-2 from the same patient shared 99.7% similarity, indicating that the virus spread across the blood-brain barrier. This is the first report to describe neurotropic DENV-2 using whole-genome analysis and to provide the clinical, immunological, and virological characteristics of dengue encephalitis patients during a severe dengue outbreak in Sri Lanka in 2017.


Assuntos
Dengue/genética , Encefalite/genética , Genoma Viral/genética , Proteínas não Estruturais Virais/genética , Adulto , Criança , Dengue/líquido cefalorraquidiano , Dengue/virologia , Vírus da Dengue/genética , Vírus da Dengue/isolamento & purificação , Encefalite/líquido cefalorraquidiano , Encefalite/virologia , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/genética , Imunoglobulina M/sangue , Imunoglobulina M/genética , Masculino , Adulto Jovem
13.
Am J Trop Med Hyg ; 102(6): 1217-1225, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32189614

RESUMO

Dengue virus (DENV) infection is a major cause of morbidity and mortality in Vietnam, and the incidence is higher and more consistent in the southern part of the country. This study investigated the circulation of DENV serotypes, viremia levels, immunological status, and cytokine levels, with disease severities among children infected in 2017 in Ho Chi Minh City, Southern Vietnam. Acute and convalescent serum samples were collected from clinically diagnosed dengue children. They were confirmed to have DENV infection by NS1 antigen, IgM and IgG ELISAs, virus isolation, and conventional and real-time RT-PCR. Measurement of 10 cytokine levels was performed in the serum samples. All the children were dengue IgM positive; 28% and 72% of them had primary and secondary DENV infections, respectively, whereas 54% of those with secondary infection were children with dengue with warning signs and with severe dengue. Any or mixed infection of the four serotypes of DENV RNA was detected in 58 children. Twenty DENV strains (DENV-1 = 16 and DENV-4 = 4) were isolated. Levels of IFN-γ, TNF-α, MCP-1, IL-10, and IL-6 were significantly higher in severe dengue cases. We report the predominance of DENV-1 over other serotypes in the 2017 dengue outbreak in Southern Vietnam. Our data showed that cytokine expressions were correlated with dengue pathogenesis and may help in identifying an effective therapeutic strategy.


Assuntos
Citocinas/sangue , Dengue/sangue , Dengue/epidemiologia , Adolescente , Anticorpos Antivirais/sangue , Criança , Pré-Escolar , Dengue/metabolismo , Dengue/patologia , Surtos de Doenças , Feminino , Regulação da Expressão Gênica , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Lactente , Masculino , Estudos Retrospectivos , Vietnã/epidemiologia
14.
J Clin Virol ; 125: 104304, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32145478

RESUMO

BACKGROUND: Sri Lanka experienced its largest dengue outbreak in 2017 with more than 185,000 dengue cases including at least 250 fatalities. OBJECTIVES: Our study aimed to characterize the clinical, immunological and virological features of confirmed dengue patients in Sri Lanka during the outbreak in 2017 when unusual manifestations of severe dengue were observed. STUDY DESIGN: Sera from 295 patients who were admitted to Teaching Hospital Kandy, Kandy, Sri Lanka between March 2017- January 2018 were subjected to NS1 antigen, IgM and IgG ELISAs, virus isolation, conventional and real time RT-PCR and next generation sequencing. RESULTS: Primary and secondary infections were detected in 48.5 % and 51.5 % of the study population, respectively. Two hundred twenty five DENV strains were isolated (219 DENV-2, one DENV-3, two DENV-4, two mixed infections of DENV-2 and -3 and one mixed infection of DENV-2 and -4). Unusual and severe manifestations such as encephalitis, encephalopathy, liver failure, kidney failure, myocarditis, Guillain-Barré syndrome and multi-organ failure were noted in 44 dengue patients with 11 deaths. The viraemia levels in patients with primary infection and unusual manifestations were significantly higher compared to those in patients with secondary infection. A new clade of DENV-2 Cosmopolitan genotype strains was observed with the strains closely related to those from China, Malaysia, Indonesia, Singapore and Taiwan. CONCLUSIONS: The new clade of DENV-2 cosmopolitan genotype observed in Sri Lanka in 2017 caused an unprecedented, severe dengue outbreak. The emergence of DENV-3 and DENV-4 in the 2017 outbreak might cause future outbreaks in Sri Lanka.


Assuntos
Vírus da Dengue/genética , Dengue/complicações , Dengue/epidemiologia , Doenças do Sistema Nervoso/virologia , Dengue Grave/epidemiologia , Adolescente , Adulto , Idoso , Anticorpos Antivirais/sangue , Criança , Pré-Escolar , Coinfecção/complicações , Coinfecção/epidemiologia , Coinfecção/virologia , Dengue/mortalidade , Vírus da Dengue/classificação , Vírus da Dengue/patogenicidade , Surtos de Doenças/prevenção & controle , Surtos de Doenças/estatística & dados numéricos , Feminino , Genótipo , Humanos , Imunoglobulina M/sangue , Lactente , Masculino , Pessoa de Meia-Idade , Doenças do Sistema Nervoso/epidemiologia , Filogenia , RNA Viral/genética , Dengue Grave/mortalidade , Sri Lanka/epidemiologia , Adulto Jovem
15.
Trans R Soc Trop Med Hyg ; 114(6): 440-447, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32043531

RESUMO

BACKGROUND: Zika virus (ZIKV) is a mosquito-borne flavivirus. Outbreaks of ZIKV infection have occurred in Africa, Southeast Asia, the Pacific Islands, the Americas and the Caribbean. Although most ZIKV infections are asymptomatic, cases of neurological manifestations have been described. The aim of the present study was to identify the prevalence of ZIKV infection among the asymptomatic persons in Myanmar in 2018. METHODS: A total of 284 serum samples from apparently healthy persons were collected from Yangon, Myanmar in 2018. They were analysed for ZIKV infection by immunoglobulin M (IgM) capture enzyme-linked immunosorbent assay (ELISA), IgG indirect ELISA, 50% focus reduction neutralization test, real-time reverse transcription polymerase chain reaction (RT-PCR) and conventional RT-PCR. RESULTS: Of the 284 apparently healthy persons, 31.3% were positive for the presence of IgM against ZIKV and 94.3% were positive for anti-flavivirus IgG. Among the ZIKV IgM-positive samples, we confirmed ZIKV infection in 15.8% of asymptomatic persons by neutralization test and real-time RT-PCR. CONCLUSIONS: We conclude that ZIKV infection was increasing among asymptomatic persons in the same area in Myanmar during 2018 compared with 2017. It is highly recommended to strengthen the surveillance system for ZIKV to prevent possible outbreaks.


Assuntos
Infecção por Zika virus , Zika virus , África , América , Animais , Anticorpos Antivirais , Região do Caribe , Humanos , Mianmar/epidemiologia , Infecção por Zika virus/epidemiologia
16.
Viruses ; 12(2)2020 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-32028555

RESUMO

Epidemics of the Chikungunya virus (CHIKV) from 2004 onwards were caused by the East/Central/South African (ECSA) genotype. However, the pathogenesis of the genotype infection has not been fully explained. In this study, we examined the pathogenic potential of CHIKV ECSA genotype M-30 (M-30) by comparing it with that of African genotype S-27 (S-27) in mice. Following low titer infections in type-I IFN receptor KO (A129) mice, we found that the M-30 infection caused high and acute fatality compared with the S-27 infection. M-30-infected A129 mice showed higher viral loads in their central nervous systems and peripheral organs, and increased levels of IFN-γ responses in their brains. Interestingly, M-30-infected mice did not show the hypophagia and reductions in weight which were observed in S-27-infected mice. Our observations provide a novel explanation of the pathogenic mechanisms attributed to virus proliferation, anti-type-II IFN response and metabolic activity in the CHIKV ECSA virus in mice.


Assuntos
Febre de Chikungunya/virologia , Vírus Chikungunya/metabolismo , Vírus Chikungunya/patogenicidade , Genótipo , África , Animais , Encéfalo/virologia , Sistema Nervoso Central/virologia , Febre de Chikungunya/fisiopatologia , Vírus Chikungunya/genética , Modelos Animais de Doenças , Camundongos , Filogenia , Carga Viral
17.
Trans R Soc Trop Med Hyg ; 114(1): 57-61, 2020 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-31638146

RESUMO

BACKGROUND: A school- and laboratory-based cross-sectional descriptive study was conducted to find out the burden of inapparent dengue virus (DENV) infection in Mandalay where DENV is endemic and there is circulation of all four DENV serotypes. METHODS: A total of 420 students who had no history of fever and visited the hospital within 6 months were recruited from three monastic schools. Serum samples were collected and the DENV genome was checked by conventional one-step RT-PCR and anti-DENV IgM and IgG antibodies were determined. Inapparent dengue (DEN) infection is defined as individuals who were either RT-PCR-positive or anti-DENV IgM-positive with no clinical manifestations or mild symptoms, and which are not linked to a visit to a healthcare provider. RESULTS: Among 420 students, 38 students (9.0%, 95% CI, 6.4 to 12.2) were confirmed as recent inapparent DEN infection. The DENV serotype-1 was detected in six students. Thirty-one out of 38 (81.6%) laboratory-confirmed inapparent DEN-infected students had primary infections and seven (18.4%) had secondary infections. CONCLUSION: This study explored the prevalence of inapparent DEN infection rate in urban monastic schools in Mandalay and showed that the rate of primary infection among inapparent DENV-infected children was high.


Assuntos
Anticorpos Antivirais/sangue , Dengue , Criança , Estudos Transversais , Dengue/epidemiologia , Vírus da Dengue/imunologia , Humanos , Mianmar/epidemiologia , Estudantes
18.
J Virol Methods ; 273: 113724, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31437465

RESUMO

Early and accurate diagnosis of dengue virus (DENV) infection is very important and Rapid Diagnostic Test (RDT) Kits are been used as a point-of-care test to check DENV infection. A Hospital and Laboratory-based descriptive study was conducted at 550-bedded Mandalay Children Hospital in 2018. Acute-phase serum samples were collected from 202 dengue suspected patients to evaluate the efficacy of RDT Kits for the diagnosis of DENV infection. Commercially available three test kits which include: ((i) CareUs Dengue Combo, Korea, (ii) Humasis Dengue Combo, Korea and (iii) Wondfo Dengue Combo, China) were validated against WHO-based reference standard tests. 140/202 patients (69.3%) was confirmed to have DENV infection. All four serotypes of dengue viruses (57 DENV-1, 7 DENV-2, 6 DENV-3 and 10 DENV-4) were identified from 80 dengue confirmed patients and DENV-1 was the dominant serotype. Combining the NS-1 antigen and IgM antibody results from the CareUs Dengue Combo Kit gave the best sensitivity (92.1%, 95% CI 86.4%-96.0%) and specificity (75.8%, 95%CI 63.3%-85.8%). Among the three RDT Kits, the performance of CareUS Kit was better than the other two. This study explored the evidence of the usefulness of RDT Kits at the point-of-care setting for diagnosis of acute dengue infection.


Assuntos
Anticorpos Antivirais/sangue , Dengue/diagnóstico , Sistemas Automatizados de Assistência Junto ao Leito/normas , Kit de Reagentes para Diagnóstico/normas , Doença Aguda , Reação de Fase Aguda/sangue , Criança , Pré-Escolar , Técnicas de Laboratório Clínico , Dengue/imunologia , Vírus da Dengue , Feminino , Hospitais , Humanos , Imunoglobulina M/sangue , Masculino , Sensibilidade e Especificidade , Sorogrupo , Proteínas não Estruturais Virais/imunologia , Organização Mundial da Saúde
19.
Am J Trop Med Hyg ; 100(3): 643-646, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30628568

RESUMO

This study was conducted to find the burden of dengue virus (DENV) and Japanese encephalitis virus (JEV) among children under the age of 13, who presented with acute encephalitis syndrome at Mandalay Children Hospital in Myanmar in 2013. Molecular and serological investigations were performed on 123 cerebrospinal fluid (CSF) samples collected from these patients. By neutralization tests and/or virus isolation, four (3.3%) JEV- and one DENV-associated encephalitis cases (0.8%) were confirmed. Antibody titer against JEV Genotype 3 was the highest among the laboratory-confirmed JEV cases. One strain of DENV-1 with Genotype 1 was isolated from the CSF sample of the dengue encephalitis patient; this was similar to the virus circulating in the study area and neighboring countries. This study shows that flaviviruses are important pathogens causing encephalitis in Myanmar. Active disease surveillance, vector control, and vaccination programs should be enforced to reduce the morbidity and mortality caused by flavivirus encephalitis.


Assuntos
Dengue/complicações , Dengue/epidemiologia , Encefalite Japonesa/epidemiologia , Anticorpos Antivirais/líquido cefalorraquidiano , Criança , Pré-Escolar , Dengue/líquido cefalorraquidiano , Vírus da Dengue/genética , Encefalite Japonesa/líquido cefalorraquidiano , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Lactente , Masculino , Mianmar/epidemiologia , Testes de Neutralização , Filogenia
20.
J Vet Med Sci ; 80(6): 985-988, 2018 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-29669948

RESUMO

Tick-borne encephalitis (TBE) and severe fever with thrombocytopenia syndrome (SFTS) are both tick-borne zoonotic diseases caused by TBE virus (TBEV) and SFTS phlebovirus (SFTSV). In 2016, a second domestic TBE case was reported in Hokkaido, Japan, after an absence of 23 years. We conducted IgG ELISA for TBEV and SFTSV on 314 deer (Cervus nippon yesoensis) serum samples collected from 3 places in Hokkaido. There were 7 seropositive samples for TBEV but none for SFTSV by ELISA. The specificity of the 7 positive samples was confirmed by neutralization tests against TBEV, and 5 sera showed 320 to 640 of 50% focus reduction endpoint titers. Our results provide information about the infectious status of TBEV in wild deer in Hokkaido, Japan.


Assuntos
Cervos/parasitologia , Vírus da Encefalite Transmitidos por Carrapatos/isolamento & purificação , Encefalite Transmitida por Carrapatos/veterinária , Animais , Encefalite Transmitida por Carrapatos/epidemiologia , Feminino , Japão/epidemiologia , Masculino , Inquéritos e Questionários
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