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1.
J Med Virol ; 95(7): e28911, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37394805

RESUMO

Mpox (previously known as Monkeypox) has recently re-emerged, primarily through human-to-human transmission in non-endemic countries including India. Virus isolation is still considered as the gold standard for diagnosis of viral infections. Here, the qPCR positive skin lesion sample from a patient was inoculated in Vero E6 cell monolayer. Characteristic cytopathic effect exhibiting typical cell rounding and detachment was observed at passage-02. The virus isolation was confirmed by qPCR. The replication kinetics of the isolate was determined that revealed maximum viral titre of log 6.3 PFU/mL at 72 h postinfection. Further, whole genome analysis through next generation sequencing revealed that the Mpox virus (MPXV) isolate is characterized by several unique SNPs and INDELs. Phylogenetically, it belonged to A.2 lineage of clade IIb, forming a close group with all other Indian MPXV along with few from USA, UK, Portugal, Thailand and Nigeria. This study reports the first successful isolation and phenotypic and genotypic characterization of MPXV from India.


Assuntos
Monkeypox virus , Humanos , Povo Asiático , Efeito Citopatogênico Viral , Genótipo , Índia , Monkeypox virus/genética , Monkeypox virus/isolamento & purificação , Monkeypox virus/patogenicidade , População do Sul da Ásia , Mpox/diagnóstico , Mpox/genética , Mpox/fisiopatologia , Mpox/virologia
2.
J Appl Microbiol ; 133(6): 3512-3522, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36007965

RESUMO

AIM: West Nile encephalitis caused by infection with the West Nile virus (WNV) is endemic in many regions of the world and is a global public health threat. The aim of this report was to develop a method using colorimetry-based reverse-transcription loop-mediated isothermal amplification (cRT-LAMP) and RT-LAMP combined with lateral-flow dipstick (LFD) for rapidly detecting WNV in low-infrastructure settings. METHODS AND RESULTS: The primers for the cRT-LAMP and RT-LAMP-LFD assays were designed based on env gene of the WNV. Primers concentration, temperature and time were optimized for cRT-LAMP and RT-LAMP-LFD. The diagnostic performance of the cRT-LAMP and RT-LAMP-LFD assays was evaluated using human serum samples from 110 patients who were clinically suspected to be infected with WNV. The RT-LAMP was performed in a heating block at 63°C for 40 min. The LAMP amplicons were visible in the lateral-flow dipstick within 5 min. The detection limit of the developed cRT-LAMP and RT-LAMP-LFD assays was 10 copies and this assay showed a high degree of specificity for WNV. Compared with quantitative real-time RT-PCR assay, the kappa value of cRT-LAMP and RT-LAMP-LFD were 0.970. CONCLUSIONS: These results showed that the newly developed WNV-specific cRT-LAMP and RT-LAMP-LFD assays can be employed as an alternative method for screening of WN-suspected human samples. The results revealed that the assay could potentially identify the virus without interference from human serum samples. Collectively, all results revealed that cRT-LAMP and RT-LAMP-LFD assays offer a suitable field-based diagnosis of WNV. SIGNIFICANCE AND IMPACT OF THE STUDY: The cRT-LAMP and LAMP-LFD platform for the detection of WNV is rapid, accurate and simple-to-perform. Our present method has not only a short turnaround time but also avoided cross-contamination problem. Moreover, the use of simple lateral flow dipsticks broadens its application potential for the point-of-care use in resource-limited settings during outbreak situations. To the best of our knowledge, this is the first report for the development of cRT-LAMP and LAMP-LFD assays for rapid, simple, specific and sensitive detection of WNV using human clinical samples and EvaGreen dye.


Assuntos
Vírus do Nilo Ocidental , Humanos , Vírus do Nilo Ocidental/genética , Sensibilidade e Especificidade , Técnicas de Amplificação de Ácido Nucleico/métodos , Técnicas de Diagnóstico Molecular , Primers do DNA/genética
3.
Indian J Med Res ; 154(4): 598-606, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-35435345

RESUMO

Background & objectives: Due to the absence of specific drugs or vaccines for Ebola virus disease, rapid, sensitive and reliable diagnostic methods are required to control the transmission chain of the disease and for better patient management. Isothermal amplification of nucleic acids has emerged as a promising alternative in which rapid and efficient amplification is achieved at a constant temperature without the thermal cycling required in PCR. Methods: A one-step single-tube accelerated quantitative reverse trascription loop-mediated isothermal amplification (RT-LAMP) assay was developed by targeting the NP gene of 2014 Zaire Ebola virus (ZEBOV). The RT-LAMP assay was found to be specific for ZEBOV, without having any cross-reactivity with related haemorrhagic fever viral agents. Results: The comparative evaluation of Ebola virus NP gene-specific RT-LAMP assay with reverse transcription (RT) - PCR and TaqMan real-time RT-PCR demonstrated that RT-LAMP was 10-1000 folds more sensitive than TaqMan real-time RT-PCR and conventional RT-PCR, respectively, with a detection limit of 1 copy number. In the absence of real-world clinical samples, the feasibility of Ebola virus RT-LAMP assay for clinical diagnosis was evaluated with different body fluids including serum, urine, saliva, semen and stool samples from healthy human volunteers spiked with gamma-irradiated ZEBOV 2014 obtained from Robert Koch Institute, Berlin, Germany, through the European Network for Diagnostics of Imported Viral Diseases. The Ebola virus RT-LAMP assay could correctly be picked up the spiked samples up to 1 copy of viral RNA without having any matrix interference. The monitoring of gene amplification can also be visualized with the naked eye by using SYBR Green I fluorescent dye. Interpretation & conclusions: Thus, due to easy operation without a requirement of sophisticated equipment and skilled personnel, the RT-LAMP assay reported here is a valuable tool as a point-of-care diagnosis for the rapid and real-time detection of Ebola virus in resource-limited healthcare settings of developing countries.


Assuntos
Ebolavirus , Doença pelo Vírus Ebola , Ebolavirus/genética , Amplificação de Genes , Doença pelo Vírus Ebola/diagnóstico , Doença pelo Vírus Ebola/genética , Humanos , Técnicas de Diagnóstico Molecular , Técnicas de Amplificação de Ácido Nucleico/métodos , Nucleoproteínas/genética , RNA Viral/análise , RNA Viral/genética , Transcrição Reversa/genética , Sensibilidade e Especificidade
4.
J Med Virol ; 91(3): 493-497, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30257043

RESUMO

Human infections caused by West Nile virus (WNV) mostly remain subclinical and self-limited. However, nearly 20% infected people suffer from febrile illness and very few of them (<1%) may get neuroinvasive illness. Mortality has been reported among children. India somehow has reported very less number of WNV cases in the past. We collected cerebrospinal fluid (CSF) samples from 75 pediatric age group patients clinically suffering from acute encephalitis syndrome. Three of these samples were positive by reverse transcriptase polymerase chain reaction using pan flavivirus primers. On sequencing of the 212 bp long-amplified fragment, it was found to be WNV belonging to lineage 1. This is probably the first report of WNV causing encephalitis from this central part of India.


Assuntos
Encefalopatia Aguda Febril/virologia , Anticorpos Antivirais/sangue , Febre do Nilo Ocidental/complicações , Febre do Nilo Ocidental/epidemiologia , Encefalopatia Aguda Febril/líquido cefalorraquidiano , Encefalopatia Aguda Febril/epidemiologia , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Imunoglobulina M/sangue , Índia/epidemiologia , Lactente , Masculino , RNA Viral/genética , Febre do Nilo Ocidental/líquido cefalorraquidiano , Vírus do Nilo Ocidental
5.
J Med Virol ; 90(5): 836-843, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29288584

RESUMO

Influenza A viruses has been associated with severe global pandemics of high morbidity and mortality with devastating impact on human health and global economy. India witnessed a major outbreak of influenza A(H1N1)pdm09 in 2015. This study comprises detailed investigation of cases died of influenza A(H1N1)pdm09 virus infection during explosive outbreak of 2015, in central part of India. To find out presence of drug resistant virus among patients who died of influenza A(H1N1)pdm09 virus infection and to find out presence of other mutations contributing to the morbidity and mortality. Twenty-two patients having confirmed influenza A(H1N1)pdm09 infection and subsequently died of this infection along with 20 non fatal cases with influenza A(H1N1)pdm09 infection were included in the study. Samples were investigated through RT-PCR/RFLP analysis, followed by nucleotide cycle sequencing of whole NA gene for detection of H275Y amino acid substitution in NA gene responsible for oseltamivir drug resistance. Out of 22 fatal cases, 6 (27.27%) were found to harbor oseltamivir resistant virus strains, whereas the H275Y mutation was not observed among the 20 non fatal cases. Amino acid substitution analysis of complete NA gene revealed V241I, N369K, N386K substitution in all strains playing synergistic role in oseltamivir drug resistance. High morbidity and mortality associated with influenza A(H1N1)pdm09 viruses can be explained by presence of drug resistant strains circulating in this outbreak. Presence of Oseltamivir resistant influenza A(H1N1)pdm09 viruses is a cause of great concern and warrants continuous screening for the circulation of drug resistant strains.


Assuntos
Antivirais/farmacologia , Farmacorresistência Viral , Vírus da Influenza A Subtipo H1N1/efeitos dos fármacos , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Influenza Humana/mortalidade , Influenza Humana/virologia , Oseltamivir/farmacologia , Adulto , Idoso , Substituição de Aminoácidos , Surtos de Doenças , Feminino , Genótipo , Humanos , Índia/epidemiologia , Influenza Humana/epidemiologia , Masculino , Pessoa de Meia-Idade , Mortalidade , Mutação de Sentido Incorreto , Neuraminidase/genética , Polimorfismo de Fragmento de Restrição , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Proteínas Virais/genética , Adulto Jovem
6.
Rev Med Virol ; 2017 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-28857363

RESUMO

Arboviruses are transmitted between arthropod vectors and vertebrate host. Arboviral infection in mosquitoes is initiated when a mosquito feeds on a viremic host. Following ingestion of a viremic blood meal by mosquitoes, virus enters midgut along with the blood, infects and replicates in midgut epithelial cells, and then escapes to the hemocoel, from where it disseminates to various secondary organs including salivary glands. Subsequently, when mosquito bites another host, a new transmission cycle is initiated. The midgut and salivary glands act as anatomical barriers to virus infection and escape. These complex interactions between the virus and vector dictate the vector competence. Thus, vector competence reflects the success in overcoming different barriers within the vector. Along with these, other intrinsic factors like midgut microbiota and immune responses, extrinsic factors like temperature and humidity, and genetic factors like vector genotype and viral genotype have been discussed in this review. Recent advancement on novel molecular tools to study vector competence is also included. Different modes of arboviral transmission like horizontal, vertical, and venereal and how these play role in sustenance and emergence of arboviruses in nature are also discussed. These factors can be exploited to reduce the susceptibility of vectors for the viruses, so as to control arboviral diseases to certain extent.

7.
Euro Surveill ; 21(5): 6-11, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26876980

RESUMO

To investigate the aetiology of the 2015 A(H1N1)pdm09 influenza outbreak in India, 1,083 nasopharyngeal swabs from suspect patients were screened for influenza A(H1N1)pdm09 in the state of Madhya Pradesh. Of 412 positive specimens, six were further characterised by phylogenetic analysis of haemagglutinin (HA) sequences revealing that they belonged to genogroup 6B. A new mutation (E164G) was observed in HA2 of two sequences. Neuraminidase genes in two of 12 isolates from fatal cases on prior oseltamivir treatment harboured the H275Y mutation.


Assuntos
Surtos de Doenças , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Influenza Humana/diagnóstico , Influenza Humana/virologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antivirais/uso terapêutico , Criança , Pré-Escolar , Genótipo , Humanos , Índia/epidemiologia , Lactente , Recém-Nascido , Influenza Humana/epidemiologia , Pessoa de Meia-Idade , Dados de Sequência Molecular , Mutação , Nasofaringe/virologia , Neuraminidase/genética , Oseltamivir/uso terapêutico , Filogenia , Vigilância da População , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Adulto Jovem
8.
Biochem Biophys Res Commun ; 436(3): 478-85, 2013 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-23756811

RESUMO

Dengue is the most important arboviral infection of global public health significance. It is now endemic in most parts of the South East Asia including India. Though Dengue virus type 2 (DENV-2) is predominantly associated with major outbreaks in India, complete genome information of Indian DENV-2 is not available. In this study, the full-length genome of five DENV-2 isolates (four from 2001 to 2011 and one from 1960), from different parts of India was determined. The complete genome of the Indian DENV-2 was found to be 10,670 bases long with an open reading frame coding for 3391 amino acids. The recent Indian DENV-2 (2001-2011) revealed a nucleotide sequence identity of around 90% and 97% with an older Indian DENV-2 (1960) and closely related Sri Lankan and Chinese DENV-2 respectively. Presence of unique amino acid residues and non-conservative substitutions in critical amino acid residues of major structural and non-structural proteins was observed in recent Indian DENV-2. Selection pressure analysis revealed positive selection in few amino acid sites of the genes encoding for structural and non-structural proteins. The molecular phylogenetic analysis based on comparison of both complete coding region and envelope protein gene with globally diverse DENV-2 viruses classified the recent Indian isolates into a unique South Asian clade within Cosmopolitan genotype. A shift of genotype from American to Cosmopolitan in 1970s characterized the evolution of DENV-2 in India. Present study is the first report on complete genome characterization of emerging DENV-2 isolates from India and highlights the circulation of a unique clade in South Asia.


Assuntos
Vírus da Dengue/genética , Evolução Molecular , Genoma Viral , RNA Viral/análise , Substituição de Aminoácidos , Sequência de Bases , Vírus da Dengue/classificação , Vírus da Dengue/isolamento & purificação , Variação Genética , Genótipo , Humanos , Índia , Fases de Leitura Aberta , Filogenia , RNA Viral/genética , Seleção Genética , Análise de Sequência de RNA , Homologia de Sequência do Ácido Nucleico , Proteínas do Envelope Viral/genética
9.
ScientificWorldJournal ; 2013: 367382, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24453838

RESUMO

Chikungunya (CHIK) fever is one of the most important arboviral infections of medical significance. The objective of the present study is to identify and characterize the etiology of a focal febrile arthritis outbreak from Gwalior, northern India, during October-November 2010. A detailed virological (isolation) and molecular (end-point RT-PCR, quantitative RT-PCR, and nucleotide sequencing) investigation of this outbreak was carried out by collecting and studying 52 clinical samples and 15 mosquito pools from the affected region. The investigation revealed the presence of CHIK viral RNA in 29% of clinical samples and 13% mosquito pool by RT-PCR. The quantification of CHIK viral RNA in samples varied from 10(2.50) to 10(6.67) copies/mL, as demonstrated through quantitative RT-PCR. In addition, six CHIK viruses were isolated from RT-PCR positive samples. The nucleotide sequences of partial E1 gene of five representative CHIK viruses were deciphered, which revealed that all the viral strains from this outbreak belong to the recently emerging ECS African genotype. Identification of Chikungunya virus ECSA African genotype as the etiology of the present outbreak confirms the continued circulation of the novel genotype, since 2006, in India. The identification of CHIK virus in Aedes aegypti also confirmed it as the major vector in northern India.


Assuntos
Infecções por Alphavirus/epidemiologia , Infecções por Alphavirus/virologia , Alphavirus/genética , Alphavirus/isolamento & purificação , Surtos de Doenças/estatística & dados numéricos , RNA Viral/genética , Adulto , Idoso , Alphavirus/classificação , Infecções por Alphavirus/diagnóstico , Sequência de Bases , Febre de Chikungunya , Feminino , Humanos , Índia/epidemiologia , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Prevalência , Fatores de Risco , Especificidade da Espécie , Adulto Jovem
10.
PLoS One ; 18(5): e0284559, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37163557

RESUMO

Kyasanur Forest Disease is a tick-borne flavivirus is endemic in the Southern India. The recent expansion and resurgence of sporadic outbreaks in southern parts of country is the most important concern. Although only formalin inactivated vaccine is available for treatment with limited efficacy the early detection and timely identification is a only way to prevent spread of cases. If the disease can be identified prior to infection in humans like in forest areas from ticks and vectors the disease spread supposed to be managed quickly. Here we have standardized a single tube ready to use dry-down probe free real time RT-PCR targeted against virus envelope gene for detection of KFDV infection. The assay was standardized in liquid format first, later it was converted into dry-down format with addition of stabilizers with a similar sensitivity and specificity (10RNA Copies/rxn). The sensitivity was comparable to the most widely used and accepted diagnostic platform i.e. TaqMan qRT-PCR. However as the reported assay here omit the need of probes makes it cost effective and dry-down reagents makes more stability to the developed assay in this study if compare to TaqMan qPCR. The assay was evaluated with KFD positive samples and healthy sample panel which revealed high concordance with TaqMan qRT-PCR. Stability was unaffected by temperature fluctuations during transportation even in cold chain free conditions, thus reduce the maintenance of strict cold storage. These findings demonstrated that the reported assay is convenient with 100% sensitivity and specificity to TaqMan qPCR. Thus this assay has the potential usefulness for diagnosis KFDV for routine surveillance in resource limited laboratory settings omitting the use costly and heat sensitive TaqMan qRT-PCR reagents without compromising the sensitivity and specificity of the diagnosis assay.


Assuntos
Vírus da Encefalite Transmitidos por Carrapatos , Doença da Floresta de Kyasanur , Humanos , Vírus da Encefalite Transmitidos por Carrapatos/genética , Região de Recursos Limitados , Reação em Cadeia da Polimerase em Tempo Real , Índia/epidemiologia , Sensibilidade e Especificidade
11.
Viruses ; 15(11)2023 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-38005871

RESUMO

Alphaviruses are serious zoonotic threats responsible for significant morbidity, causing arthritis or encephalitis. So far, no licensed drugs or vaccines are available to combat alphaviral infections. About 300,000 chikungunya virus (CHIKV) infections have been reported in 2023, with more than 300 deaths, including reports of a few cases in the USA as well. The discovery and development of small-molecule drugs have been revolutionized over the last decade. Here, we employed a cell-based screening approach using a series of in-house small-molecule libraries to test for their ability to inhibit CHIKV replication. DCR 137, a quinazoline derivative, was found to be the most potent inhibitor of CHIKV replication in our screening assay. Both, the cytopathic effect, and immunofluorescence of infected cells were reduced in a dose-dependent manner with DCR 137 post-treatment. Most importantly, DCR 137 was more protective than the traditional ribavirin drug and reduced CHIKV plaque-forming units by several log units. CHIKV-E2 protein levels were also reduced in a dose-dependent manner. Further, DCR 137 was probed for its antiviral activity against another alphavirus, the Ross River virus, which revealed effective inhibition of viral replication. These results led to the identification of a potential quinazoline candidate for future optimization that might act as a pan-alphavirus inhibitor.


Assuntos
Febre de Chikungunya , Vírus Chikungunya , Humanos , Ross River virus , Linhagem Celular , Antivirais/farmacologia , Vírus Chikungunya/fisiologia , Quinazolinas/farmacologia , Replicação Viral
12.
Virol J ; 9: 27, 2012 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-22264275

RESUMO

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


Assuntos
Aedes/virologia , Compostos Orgânicos/metabolismo , Reação em Cadeia da Polimerase em Tempo Real/métodos , Virologia/métodos , Vírus da Febre Amarela/isolamento & purificação , Regiões 5' não Traduzidas , Animais , Benzotiazóis , Proteínas do Capsídeo/genética , Diaminas , Feminino , Humanos , Quinolinas , RNA Viral/genética , Reação em Cadeia da Polimerase em Tempo Real/economia , Sensibilidade e Especificidade , Coloração e Rotulagem/economia , Coloração e Rotulagem/métodos , Vírus da Febre Amarela/genética
13.
Virus Res ; 313: 198717, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35189158

RESUMO

Crimean-Congo hemorrhagic fever (CCHF) is an important tick borne zoonotic viral disease of humans. CCHF virus causes sporadic cases of severe illness across a huge geographic area across Africa to Europe to Asia including India. CCHF has emerged as a major public health concern in western Indian states including Gujarat and Rajasthan, where regular human cases were reported since the year 2011. Human serve as the dead-end host, and they gain infection via infected tick bite, in close contact with ruminants and from slaughter house. Currently, the detection of this fatal infection is limited to BSL-4 laboratory which is scarce even in developed economies. Thus, a safe, sensitive assay for early immunodiagnosis is crucial for disease management and containing the outbreak. In this study, the conserved recombinant nucleoprotein was exploited as a safe, scalable alternate antigen for development of indirect IgM and IgG ELISA detection platform. The indirect ELISA was evaluated using suspected clinical samples collected from hotspot areas in India. Comparison with reference MAC ELISA and IgG ELISA revealed a correlation of 95% and 100% respectively. The results indicate that the developed IgM and IgG indirect ELISA has high sensitivity and specificity for detecting CCHFV antibodies among human. These assays are easy to perform and can be employed for high throughput screening of human samples for clinical diagnosis as well as serosurveillance. These assays are also amenable for conversion to low-cost point of care testing formats for application in resource limited settings.


Assuntos
Vírus da Febre Hemorrágica da Crimeia-Congo , Febre Hemorrágica da Crimeia , Animais , Anticorpos Antivirais , Diagnóstico Precoce , Ensaio de Imunoadsorção Enzimática/métodos , Febre Hemorrágica da Crimeia/diagnóstico , Febre Hemorrágica da Crimeia/epidemiologia , Humanos , Índia/epidemiologia
14.
Acta Trop ; 231: 106435, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35378061

RESUMO

Presently diagnosis of Crimean Congo Hemorrhagic Fever virus (CCHFV) infection relies on real-time and end-point RT-PCR, and serodiagnostic assay. These assays are time consuming and cannot be used as a routine screening test. The objective of this study was to develop a rapid diagnostic test that could be completed in < 60 minutes. Rapid detection of CCHFV infection is important for faster delivery of appropriate therapeutics, clinical management of patient and also important to contain the outbreak. In the present study, we have developed a rapid and sensitive single tube reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for detection of CCHFV. The limit of detection of RT-LAMP vis-a-vis Real-time RT-PCR assay is 10 RNA copies. Further, CCHFV specific RT-LAMP assay was successfully evaluated with human and tick samples. The assay correctly picked up diverse CCHFV isolates indicating its applicability for different strains. A comparative evaluation of the RT-LAMP assay vis-à-vis with the real-time RT-PCR revealed 100% concordance with 100 % sensitivity and specificity respectively. No cross reactivity with related Flaviviruses and hemorrhagic fever viruses was observed. The assay is a rapid, isothermal, simple to perform molecular diagnostic, which can be performed in a portable heating block device. CCHF RT-LAMP assay can be used in low resource laboratories for monitoring of CCHFV outbreaks in remote rural regions in affected countries.


Assuntos
Vírus da Febre Hemorrágica da Crimeia-Congo , Febre Hemorrágica da Crimeia , Vírus da Febre Hemorrágica da Crimeia-Congo/genética , Febre Hemorrágica da Crimeia/diagnóstico , Humanos , Técnicas de Diagnóstico Molecular , Técnicas de Amplificação de Ácido Nucleico , RNA Viral/análise , RNA Viral/genética , Transcrição Reversa , Sensibilidade e Especificidade
15.
Acta Trop ; 235: 106623, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35940341

RESUMO

Kyasanur forest virus disease (KFD) is a major public health concern in India. Its etiology KFD virus causes haemorrhagic fever with severe sequelae in humans. Due to continuous spatiotemporal expansion of KFD in last decade, the incidences of positive cases have been increasing in both humans and primates. Early diagnosis is of prime importance for disease management and epidemiological containment. In the present study, the highly immunogenic Envelope Domain III (EDIII) antigen was produced using prokaryotic expression system with an yield of 8 mg/L. The protein was purified using affinity chromatography and confirmed for its immuno-reactivity by western blot and UPLCMS/MS analysis. The recombinant EDIII was used as an antigen for the standardization of ELISA to detect anti KFD IgM antibodies in humans. The ROC curve was prepared to set the optimum cut-off OD for the assay. The comparative evaluation of the assay with a reference MAC ELISA revealed 86.96% concordance, 82.22% sensitivity and 91.48% specificity. Inter-rater agreement was performed with kappa index revealing significant agreement between the assays. This is the first study using safe recombinant protein antigen-based detection of anti KFDV antibodies in humans. This simple and scalable ELISA assay will be applicable for large scale screening of samples for combating the emerging threats of KFD in newer territories.


Assuntos
Vírus da Encefalite Transmitidos por Carrapatos , Doença da Floresta de Kyasanur , Animais , Anticorpos Antivirais , Ensaio de Imunoadsorção Enzimática/métodos , Humanos , Imunoglobulina M , Doença da Floresta de Kyasanur/diagnóstico , Doença da Floresta de Kyasanur/epidemiologia , Proteínas Recombinantes/genética
16.
J Gen Virol ; 92(Pt 7): 1595-1600, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21411675

RESUMO

Dengue is endemic in most parts of the tropics including India. So far, complete genome information for Indian dengue isolates is not available. In the present study, we characterized the genome of three dengue type 3 viruses isolated from India. The genomes of all three viruses were found to be 10,707 bp long with an ORF encoding 3390 aa. Extensive molecular phylogenetic analysis based on comparison of the complete genome and envelope gene classified the recent Indian viruses into genotype III (lineage III), revealing a shift of lineage from lineage V. The sequence analysis revealed several non-conservative changes in major structural proteins. This study clearly indicates that the genotype III (lineage III) dengue type 3 viruses have been continuously circulating in major parts of India since 2003 and are responsible for the recent major outbreaks all over India. This is the first extensive study on complete genome analysis of dengue type 3 viruses in India.


Assuntos
Vírus da Dengue/genética , Vírus da Dengue/isolamento & purificação , Dengue/virologia , Genoma Viral , Dengue/epidemiologia , Vírus da Dengue/classificação , Surtos de Doenças , Genótipo , Humanos , Índia/epidemiologia , Dados de Sequência Molecular , Fases de Leitura Aberta , Filogenia
17.
Int J Infect Dis ; 112: 346-351, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33486011

RESUMO

SIGNIFICANCE: Kyasanur forest disease (KFD), a re-emerging tick-borne viral disease, causes severe hemorrhagic fever in humans and nonhuman primates. KFD virus (KFDV) is a member of the genus Flavivirus. KFD is now increasingly reported outside its endemic zone in India. Rapid and specific detection of the KFDV plays a critical role in containment of the outbreak. The diagnosis of KFD currently relies on real-time RT-PCR, nested RT-PCR, end point RT-PCR, and serodiagnostic assay. These assays are tedious, time-consuming, and cannot be used as a routine screening platform. OBJECTIVE: The present study was aimed to develop a one-step reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for molecular diagnosis of KFD. DESIGN: The gene amplification reaction was accomplished by incubation at a constant temperature of 63°C for 60min. RESULTS: The limit of detection of RT-LAMP assay was 10 copies. KFD RT-LAMP assay was successfully evaluated with diverse host samples including humans, monkeys, and tick. The assay correctly picked up different KFD isolates indicating its applicability for divergent strains. Comparative evaluation of RT-LAMP assay with quantitative TaqMan real-time RT-PCR revealed 100% concordance. No cross-reaction with related flavi and other hemorrhagic fever viruses was observed, indicating its high specificity. CONCLUSION AND RELEVANCE: The RT-LAMP test developed in this study will serve as a rapid, sensitive alternate detection method for KFDV infection and would be useful for high throughput screening of clinical samples in resource limited areas during outbreaks.


Assuntos
Vírus da Encefalite Transmitidos por Carrapatos , Animais , Vírus da Encefalite Transmitidos por Carrapatos/genética , Técnicas de Diagnóstico Molecular , Técnicas de Amplificação de Ácido Nucleico , Reação em Cadeia da Polimerase em Tempo Real , Transcrição Reversa , Sensibilidade e Especificidade
18.
Sci Rep ; 11(1): 14699, 2021 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-34282163

RESUMO

Crimean-Congo hemorrhagic fever (CCHF) virus, a highly pathogenic viral agent is responsible for severe fatal hemorrhagic infections in many parts of the world. The early diagnosis of CCHF infection is important for successful clinical management and epidemiological control. The nucleoprotein (NP) of CCHFV being highly conserved and immunogenic is used as early diagnostic marker. In this study, we report a rapid and sensitive double antibody based antigen capture ELISA to detect Crimean-Congo hemorrhagic fever virus (CCHFV). Highly specific polyclonal and monoclonal antibody against NP has been generated and used as capture and detector antibody respectively. The assay was able to detect viral nucleoprotein in different matrices including human serum, ticks and culture supernatant. The detection limit of the developed sandwich ELISA assay was 25 ng of purified antigen. Comparison with a real time RT-PCR revealed its detection limit to be 1000 genome equivalents of CCHFV. Further the assay was comparatively evaluated with a commercial kit employing gamma irradiated CCHFV, revealing a sensitivity and specificity of 100%. This newly developed sandwich ELISA (sELISA) with high sensitivity and specificity could be used as an efficient method for the detection of CCHF virus in humans, ticks and culture supernatant. The assay will be useful as alternate tool for diagnosis of acute infection and is amenable for screening of large scale samples in resource limited settings.


Assuntos
Anticorpos Antivirais/metabolismo , Vírus da Febre Hemorrágica da Crimeia-Congo/imunologia , Febre Hemorrágica da Crimeia/diagnóstico , Animais , Anticorpos Antivirais/sangue , Anticorpos Antivirais/isolamento & purificação , Especificidade de Anticorpos , Reações Cruzadas/imunologia , Testes Diagnósticos de Rotina/métodos , Ensaio de Imunoadsorção Enzimática/métodos , Feminino , Células HEK293 , Febre Hemorrágica da Crimeia/sangue , Febre Hemorrágica da Crimeia/imunologia , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Coelhos , Fatores de Tempo
19.
Sci Rep ; 11(1): 18126, 2021 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-34518554

RESUMO

COVID-19 has emerged as global pandemic with largest damage to the public health, economy and human psyche.The genome sequence data obtained during the ongoing pandemic are valuable to understand the virus evolutionary patterns and spread across the globe. Increased availability of genome information of circulating SARS-CoV-2 strains in India will enable the scientific community to understand the emergence of new variants and their impact on human health. The first case of COVID-19 was detected in Chambal region of Madhya Pradesh state in mid of March 2020 followed by multiple introduction events and expansion of cases within next three months. More than 5000 COVID-19 suspected samples referred to Defence Research and Development Establishment, Gwalior, Madhya Pradesh were analyzed during the nation -wide lockdown and unlock period. A total of 136 cases were found positive over a span of three months that included virus introduction to the region and its further spread. Whole genome sequences employing Oxford nanopore technology were generated for 26 SARS-CoV-2 circulating in 10 different districts in Madhya Pradesh state of India. This period witnessed index cases with multiple travel histories responsible for introduction of COVID-19 followed by remarkable expansion of virus. The genome wide substitutions including in important viral proteins were identified. The detailed phylogenetic analysis revealed the circulating SARS-CoV-2 clustered in multiple clades including A2a, A4 and B. The cluster-wise segregation was observed, suggesting multiple introduction links and subsequent evolution of virus in the region. This is the first comprehensive whole genome sequence analysis from central India, which revealed the emergence and evolution of SARS-CoV-2 during thenation-wide lockdown and unlock.


Assuntos
COVID-19/diagnóstico , Mutação de Sentido Incorreto , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/genética , COVID-19/epidemiologia , COVID-19/virologia , Evolução Molecular , Genoma Viral/genética , Índia , Reação em Cadeia da Polimerase Multiplex/métodos , Pandemias/prevenção & controle , Filogenia , SARS-CoV-2/classificação , SARS-CoV-2/fisiologia , Sequenciamento Completo do Genoma/métodos
20.
Eur J Pharm Sci ; 151: 105396, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32479862

RESUMO

Recurrent outbreaks of Crimean-Congo hemorrhagic fever (CCHF) virus infection in different parts of world are a major global health concern. The CCHF viral infection is associated with severe hemorrhagic fevers and mortality up to 40%. More than 30 countries in Asia, Europe and Africa are affected with CCHF infection. Prevention of infection through vaccine becomes more important when no effective antiviral and associated therapies are available. Further ticks play a crucial role in maintenance and transmission of CCHFV. Therefore, the control of transmission by ticks is warranted for ultimate prevention of outbreak. The study employed a series of immunoinformatics approaches to design novel multiepitope vaccine targeting highly immunodominant epitopes of major structural proteins (Nucleoprotein and Glycoprotein complex) of CCHFV. Vaccine was designed by incorporating linear and conformational B cell, helper and cytotoxic T cell epitopes from these crucial immunogenic proteins adjoined with appropriate linkers and adjuvant. This vaccine construct was also complemented with a highly immunogenic and conserved protective tick salivary antigen named subolesin to impart dual activity as a unique transmission blocking vaccine. The B-cell peptides were also experimentally validated. The designed vaccine was further in silico validated for its physiochemical properties, allergenicity and immunogenicity etc. The proposed candidate vaccine construct has the potential to function both as a vaccine against CCHF virus as well as a universal anti-tick vaccine.


Assuntos
Vírus da Febre Hemorrágica da Crimeia-Congo , Febre Hemorrágica da Crimeia , Carrapatos , Vacinas , Animais , Simulação por Computador , Europa (Continente) , Febre Hemorrágica da Crimeia/prevenção & controle
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