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Machain-Williams C, Reyes-Solis GC, Blitvich BJ, Laredo-Tiscareño V, Dzul-Rosado AR, Kim S, AbuBakar S. Evaluation of an Immunoglobulin E Capture Enzyme-Linked Immunosorbent Assay for the Early Diagnosis of Dengue. Viral Immunol 2023; 36:101-109. [PMID: 36862827 DOI: 10.1089/vim.2022.0110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023] Open
Abstract
Dengue virus (DENV) is the etiological agent of dengue, the most important mosquito-transmitted viral disease of humans worldwide. Enzyme-linked immunosorbent assays (ELISAs) designed to detect DENV IgM are commonly used for dengue diagnosis. However, DENV IgM is not reliably detected until ≥4 days after illness onset. Reverse transcription-polymerase chain reaction (RT-PCR) can diagnose early dengue but requires specialized equipment, reagents, and trained personnel. Additional diagnostic tools are needed. Limited work has been performed to determine whether IgE-based assays can be used for the early detection of vector-borne viral diseases, including dengue. In this study, we determined the efficacy of a DENV IgE capture ELISA for the detection of early dengue. Sera were collected within the first 4 days of illness onset from 117 patients with laboratory-confirmed dengue, as determined by DENV-specific RT-PCR. The serotypes responsible for the infections were DENV-1 and DENV-2 (57 and 60 patients, respectively). Sera were also collected from 113 dengue-negative individuals with febrile illness of undetermined etiology and 30 healthy controls. The capture ELISA detected DENV IgE in 97 (82.9%) confirmed dengue patients and none of the healthy controls. There was a high false positivity rate (22.1%) among the febrile non-dengue patients. In conclusion, we provide evidence that IgE capture assays have the potential to be explored for early diagnosis of dengue, but further research is necessary to address the possible false positivity rate among patients with other febrile illnesses.
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Affiliation(s)
- Carlos Machain-Williams
- Laboratorio de Arbovirologia, Centro de Investigaciones Regionales "Dr. Hideyo Noguchi," Universidad Autónoma de Yucatan, Merida, Yucatan, Mexico
| | - Guadalupe C Reyes-Solis
- Laboratorio de Arbovirologia, Centro de Investigaciones Regionales "Dr. Hideyo Noguchi," Universidad Autónoma de Yucatan, Merida, Yucatan, Mexico
| | - Bradley J Blitvich
- Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Viridiana Laredo-Tiscareño
- Laboratorio de Arbovirologia, Centro de Investigaciones Regionales "Dr. Hideyo Noguchi," Universidad Autónoma de Yucatan, Merida, Yucatan, Mexico.,Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | | | - Sungmin Kim
- Department of Infectious Diseases in Internal Medicine, Sejong Chungnam National University Hospital, School of Medicine, Chungnam National University, Sejong, Korea
| | - Sazaly AbuBakar
- Tropical Infectious Diseases Research and Education Centre (TIDREC), Higher Institution Center of Excellence (HICOE), Universiti Malaya, Kuala Lumpur, Malaysia
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Sánchez-Vargas I, Harrington LC, Doty JB, Black WC, Olson KE. Demonstration of efficient vertical and venereal transmission of dengue virus type-2 in a genetically diverse laboratory strain of Aedes aegypti. PLoS Negl Trop Dis 2018; 12:e0006754. [PMID: 30169505 PMCID: PMC6136804 DOI: 10.1371/journal.pntd.0006754] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 09/13/2018] [Accepted: 08/14/2018] [Indexed: 12/20/2022] Open
Abstract
Aedes aegypti is the primary mosquito vector of dengue viruses (DENV; serotypes 1-4). Human-mosquito transmission cycles maintain DENV during epidemics but questions remain regarding how these viruses survive when human infections and vector abundance are minimal. Aedes mosquitoes can transmit DENV within the vector population through two alternate routes: vertical and venereal transmission (VT and VNT, respectively). We tested the efficiency of VT and VNT in a genetically diverse laboratory (GDLS) strain of Ae. aegypti orally infected with DENV2 (Jamaica 1409). We examined F1 larvae from infected females generated during the first and second gonotrophic cycles (E1 and E2) for viral envelope (E) antigen by amplifying virus in C6/36 cells and then performing an indirect immunofluorescence assay (IFA). RT-PCR/nested PCR analyses confirmed DENV2 RNA in samples positive by IFA. We observed VT of virus to larvae and adult male progeny and VNT of virus to uninfected virgin females after mating with males that had acquired virus by the VT route. We detected no DENV2 in 30 pools (20 larvae/pool) of F1 larvae following the first gonotrophic cycle, suggesting limited virus dissemination at 7 days post-infection. DENV2 was detected by IFA in 27 of 49 (55%) and 35 of 51 (68.6%) F1 larval pools (20 larvae/pool) from infected E2 females that received a second blood meal without virus at 10 or 21 days post-infection (E2-10d-F1 and E2-21-F1), respectively. The minimum filial infection rates by IFA for E2-10d-F1 and E2-21d-F1 mosquitoes were 1:36 and 1:29, respectively. The VNT rate from E2-10d-F1 males to virgin (uninfected) GDLS females was 31.6% (118 of 374) at 8 days post mating. Twenty one percent of VNT-infected females receiving a blood meal prior to mating had disseminated virus in their heads, suggesting a potential pathway for virus to re-enter the human-mosquito transmission cycle. This is the first report of VNT of DENV by male Ae. aegypti and the first demonstration of sexual transmission in Aedes by naturally infected males. Our results demonstrate the potential for VT and VNT of DENV in nature as mechanisms for virus maintenance during inter-epidemic periods.
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Affiliation(s)
- Irma Sánchez-Vargas
- Arthropod-borne Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Ft. Collins, CO, United States of America
| | - Laura C. Harrington
- Department of Entomology, Cornell University, Ithaca, NY, United States of America
| | - Jeffrey B. Doty
- Centers for Disease Control and Prevention, Poxvirus and Rabies Branch, Atlanta, Georgia, United States of America
| | - William C. Black
- Arthropod-borne Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Ft. Collins, CO, United States of America
| | - Ken E. Olson
- Arthropod-borne Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Ft. Collins, CO, United States of America
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Galán-Huerta K, Martínez-Landeros E, Delgado-Gallegos J, Caballero-Sosa S, Malo-García I, Fernández-Salas I, Ramos-Jiménez J, Rivas-Estilla A. Molecular and Clinical Characterization of Chikungunya Virus Infections in Southeast Mexico. Viruses 2018; 10:248. [DOI: https:/doi.org/10.3390/v10050248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
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Molecular and Clinical Characterization of Chikungunya Virus Infections in Southeast Mexico. Viruses 2018; 10:v10050248. [PMID: 29747416 PMCID: PMC5977241 DOI: 10.3390/v10050248] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 04/29/2018] [Accepted: 04/30/2018] [Indexed: 12/28/2022] Open
Abstract
Chikungunya fever is an arthropod-borne infection caused by Chikungunya virus (CHIKV). Even though clinical features of Chikungunya fever in the Mexican population have been described before, there is no detailed information. The aim of this study was to perform a full description of the clinical features in confirmed Chikungunya-infected patients and describe the molecular epidemiology of CHIKV. We evaluated febrile patients who sought medical assistance in Tapachula, Chiapas, Mexico, from June through July 2015. Infection was confirmed with molecular and serological methods. Viruses were isolated and the E1 gene was sequenced. Phylogeny reconstruction was inferred using maximum-likelihood and maximum clade credibility approaches. We studied 52 patients with confirmed CHIKV infection. They were more likely to have wrist, metacarpophalangeal, and knee arthralgia. Two combinations of clinical features were obtained to differentiate between Chikungunya fever and acute undifferentiated febrile illness. We obtained 10 CHIKV E1 sequences that grouped with the Asian lineage. Seven strains diverged from the formerly reported. Patients infected with the divergent CHIKV strains showed a broader spectrum of clinical manifestations. We defined the complete clinical features of Chikungunya fever in patients from Southeastern Mexico. Our results demonstrate co-circulation of different CHIKV strains in the state of Chiapas.
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Electrospun manganese (III) oxide nanofiber based electrochemical DNA-nanobiosensor for zeptomolar detection of dengue consensus primer. Biosens Bioelectron 2017; 90:378-387. [DOI: 10.1016/j.bios.2016.12.008] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 12/01/2016] [Accepted: 12/03/2016] [Indexed: 01/14/2023]
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Aedes albopictus (Skuse, 1894) infected with the American-Asian genotype of dengue type 2 virus in Medellín suggests its possible role as vector of dengue fever in Colombia. BIOMEDICA 2017; 37:135-142. [PMID: 29161485 DOI: 10.7705/biomedica.v37i0.3474] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 07/11/2017] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Aedes aegypti and Ae. albopictus are recognized vectors of dengue, yellow fever, chikungunya and Zika arboviruses in several countries worldwide. In Colombia, Ae. albopictus geographical distribution has increased to include highly populated cities such as Cali and Medellín. Although this species has been frequently found in urban and semi-urban zones in the country, its role as vector of the dengue fever is poorly known. OBJECTIVE To identify the presence of Ae. albopictus specimens naturally infected with dengue virus collected in Medellín. MATERIALS AND METHODS Insects were collected in the Universidad Nacional de Colombia campus in Medellín. Individuals were classified as Ae. albopictus and confirmed by DNA barcode region analysis. Mosquitoes were processed for dengue virus identification, and a fragment of the NS3 gen was sequenced and compared with DENV-2 genotypes reported in the literature. RESULTS Sequence analysis of COI indicated Ae. albopictus individuals were similar to those recently reported in Colombia, and genetically close to those from other regions worldwide. Among the pools tested one was positive for DENV-2, and the NS3 analysis indicated it belonged to the Asian-American clade. CONCLUSION We report the presence Ae. albopictus naturally infected with the Asian-American genotype of DENV-2 in Colombia. The presence of Ae. albopictus specimens carrying the most common genotype infecting humans in a highly populated city such as Medellín indicates its potential role as dengue vector in Colombia and highlights the relevance of including it in current vector surveillance strategies.
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Peña-García VH, Triana-Chávez O, Mejía-Jaramillo AM, Díaz FJ, Gómez-Palacio A, Arboleda-Sánchez S. Infection Rates by Dengue Virus in Mosquitoes and the Influence of Temperature May Be Related to Different Endemicity Patterns in Three Colombian Cities. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 13:ijerph13070734. [PMID: 27455289 PMCID: PMC4962275 DOI: 10.3390/ijerph13070734] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 06/13/2016] [Accepted: 06/15/2016] [Indexed: 12/14/2022]
Abstract
Colombia is an endemic country for dengue fever where the four serotypes of virus dengue (DENV1–4) circulate simultaneously, and all types are responsible for dengue cases in the country. The control strategies are guided by entomological surveillance. However, heterogeneity in aedic indices is not well correlated with the incidence of the disease in cities such as Riohacha, Bello and Villavicencio. As an alternative, molecular detection of dengue virus in mosquitoes has been proposed as a useful tool for epidemiological surveillance and identification of serotypes circulating in field. We conducted a spatiotemporal fieldwork in these cities to capture adult mosquitoes to assess vector infection and explain the differences between Breteau indices and disease incidence. DENV infection in females and DENV serotype identification were evaluated and infection rates (IR) were estimated. The relationship between density, dengue cases and vector index was also estimated with logistic regression modeling and Pearson’s correlation coefficient. The lack of association between aedic indices and dengue incidence is in agreement with the weak associations between the density of the mosquitoes and their infection with DENV in the three cities. However, association was evident between the IR and dengue cases in Villavicencio. Furthermore, we found important negative associations between temperature and lag time from two to six weeks in Riohacha. We conclude that density of mosquitoes is not a good predictor of dengue cases. Instead, IR and temperature might explain better such heterogeneity.
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Affiliation(s)
- Víctor Hugo Peña-García
- Grupo de Biología y Control de Enfermedades Infecciosas, Universidad de Antioquia, Sede de Investigaciones Universitarias (SIU), Calle 62 # 52-59 Laboratory 620, P.O. Box: 1226, Medellín 050010, Colombia.
| | - Omar Triana-Chávez
- Grupo de Biología y Control de Enfermedades Infecciosas, Universidad de Antioquia, Sede de Investigaciones Universitarias (SIU), Calle 62 # 52-59 Laboratory 620, P.O. Box: 1226, Medellín 050010, Colombia.
| | - Ana María Mejía-Jaramillo
- Grupo de Biología y Control de Enfermedades Infecciosas, Universidad de Antioquia, Sede de Investigaciones Universitarias (SIU), Calle 62 # 52-59 Laboratory 620, P.O. Box: 1226, Medellín 050010, Colombia.
| | - Francisco J Díaz
- Grupo de Inmunovirología, Universidad de Antioquia, Sede de Investigaciones Universitarias, SIU, Calle 62 # 52-59 Laboratory 532, P.O. Box: 1226, Medellín 050010, Colombia.
| | - Andrés Gómez-Palacio
- Grupo de Biología y Control de Enfermedades Infecciosas, Universidad de Antioquia, Sede de Investigaciones Universitarias (SIU), Calle 62 # 52-59 Laboratory 620, P.O. Box: 1226, Medellín 050010, Colombia.
| | - Sair Arboleda-Sánchez
- Grupo de Biología y Control de Enfermedades Infecciosas, Universidad de Antioquia, Sede de Investigaciones Universitarias (SIU), Calle 62 # 52-59 Laboratory 620, P.O. Box: 1226, Medellín 050010, Colombia.
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Abstract
The existing knowledge on pathogenesis and aetiology of DHF establishes that Dengue Hemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS) are caused by two subsequent infections of two different serotypes of dengue affecting a common human population with a time gap. Present studies have been undertaken on 212 laboratory reared infected individual mosquitoes from larvae collected from 31 dengue endemic towns of Rajasthan, India. Type specific DEN viruses were detected from individual mosquitoes employing RT-PCR. In 78.7% of 212 infected individual mosquitoes studied, vertically transmitted multiple DENV types were observed. We report for the first time that single mosquitoes contain multiple dengue virus types.
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Senapati S, Slouka Z, Shah SS, Behura SK, Shi Z, Stack MS, Severson DW, Chang HC. An ion-exchange nanomembrane sensor for detection of nucleic acids using a surface charge inversion phenomenon. Biosens Bioelectron 2014; 60:92-100. [PMID: 24787123 PMCID: PMC4445831 DOI: 10.1016/j.bios.2014.04.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 04/01/2014] [Accepted: 04/02/2014] [Indexed: 11/23/2022]
Abstract
We present a novel low-cost biosensor for rapid, sensitive and selective detection of nucleic acids based on an ionic diode feature of an anion exchange nanoporous membrane under DC bias. The ionic diode feature is associated with external surface charge inversion on the positively charged anion exchange nanomembrane upon hybridization of negatively charged nucleic acid molecules to single-stranded oligoprobes functionalized on the membrane surface resulting in the formation of a cation selective monolayer. The resulting bipolar membrane causes a transition from electroconvection-controlled to water-splitting controlled ion conductance, with a large ion current signature that can be used to accurately quantify the hybridized nucleic acids. The platform is capable of distinguishing two base-pair mismatches in a 22-base pairing segment of microRNAs associated with oral cancer, as well as serotype-specific detection of dengue virus. We also show the sensor' capability to selectively capture target nucleic acids from a heterogeneous mixture. The limit of detection is 1 pM for short 27 base target molecules in a 15-min assay. Similar hybridization results are shown for short DNA molecules as well as RNAs from Brucella and Escherichia coli. The versatility and simplicity of this low-cost biosensor should enable point-of-care diagnostics in food, medical and environmental safety markets.
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Affiliation(s)
- Satyajyoti Senapati
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556, USA; Advanced Diagnostics & Therapeutics, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Zdenek Slouka
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Sunny S Shah
- Advanced Diagnostics & Therapeutics, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Susanta K Behura
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Zonggao Shi
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA
| | - M Sharon Stack
- Advanced Diagnostics & Therapeutics, University of Notre Dame, Notre Dame, IN 46556, USA; Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA
| | - David W Severson
- Advanced Diagnostics & Therapeutics, University of Notre Dame, Notre Dame, IN 46556, USA; Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Hsueh-Chia Chang
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556, USA; Advanced Diagnostics & Therapeutics, University of Notre Dame, Notre Dame, IN 46556, USA; Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556, USA.
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Wang Y, Wang Z, Zhang Y, Bai L, Zhao Y, Liu C, Ma A, Yu H. Polymerase chain reaction-based assays for the diagnosis of human brucellosis. Ann Clin Microbiol Antimicrob 2014; 13:31. [PMID: 25082566 PMCID: PMC4236518 DOI: 10.1186/s12941-014-0031-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 07/09/2014] [Indexed: 12/14/2022] Open
Abstract
Polymerase chain reaction (PCR) is an in vitro technique for the nucleic acid amplification, which is commonly used to diagnose infectious diseases. The use of PCR for pathogens detection, genotyping and quantification has some advantages, such as high sensitivity, high specificity, reproducibility and technical ease. Brucellosis is a common zoonosis caused by Brucella spp., which still remains as a major health problem in many developing countries around the world. The direct culture and immunohistochemistry can be used for detecting infection with Brucella spp. However, PCR has the potential to address limitations of these methods. PCR are now one of the most useful assays for the diagnosis in human brucellosis. The aim of this review was to summarize the main PCR techniques and their applications for diagnosis and follow-up of patients with brucellosis. Moreover, advantages or limitation of the different PCR methods as well as the evaluation of PCR results for treatment and follow-up of human brucellosis were also discussed.
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Loroño-Pino MA, García-Rejón JE, Machain-Williams C, Gomez-Carro S, Nuñez-Ayala G, Nájera-Vázquez MDR, Losoya A, Aguilar L, Saavedra-Rodriguez K, Lozano-Fuentes S, Beaty MK, Black WC, Keefe TJ, Eisen L, Beaty BJ. Towards a Casa Segura: a consumer product study of the effect of insecticide-treated curtains on Aedes aegypti and dengue virus infections in the home. Am J Trop Med Hyg 2013; 89:385-97. [PMID: 23732254 DOI: 10.4269/ajtmh.12-0772] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The home, or domicile, is the principal environment for transmission of dengue virus (DENV) between humans and mosquito vectors. Community-wide distribution of insecticide-treated curtains (ITCs), mimicking vector control program-driven interventions, has shown promise to reduce DENV infections. We conducted a Casa Segura consumer product intervention study in Mérida, Mexico to determine the potential to reduce intradomicillary DENV transmission through ITC use in individual homes. Dengue virus infections in mosquitoes and in humans were reduced in homes with ITCs in one of two study subareas. Overall, ITCs reduced intradomicillary DENV transmission; ITC homes were significantly less likely to experience multiple DENV infections in humans than NTC homes. Dengue virus-infected Aedes aegypti females were reduced within the ITC homes where curtain use was highest. Some homes yielded up to nine infected Ae. aegypti females. This study provides insights regarding best practices for Casa Segura interventions to protect homes from intradomicillary DENV transmission.
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Affiliation(s)
- María Alba Loroño-Pino
- Laboratorio de Arbovirología, Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico.
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Voge NV, Sánchez-Vargas I, Blair CD, Eisen L, Beaty BJ. Detection of dengue virus NS1 antigen in infected Aedes aegypti using a commercially available kit. Am J Trop Med Hyg 2012. [PMID: 23185074 DOI: 10.4269/ajtmh.2012.12-0477] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Epidemic dengue has emerged throughout the tropical world. In the continued absence of a vaccine against dengue virus (DENV), mosquito vector surveillance and control programs are essential to reduce human infections. An effective test to detect DENV in infected mosquitoes would be a valuable addition to the surveillance effort. We investigated DENV detection in infected Aedes aegypti using a commercially available DENV non-structural protein 1 (NS1) ELISA kit (Platelia Dengue NS1 Ag), and by reverse transcription-polymerase chain reaction (RT-PCR) and virus isolation assays. The DENV-infected mosquitoes were subjected to field-relevant conditions and assayed individually and pooled with uninfected mosquitoes. Overall, DENV NS1 antigen was detected in 98% of infected mosquitoes/pools versus 79% for RT-PCR and 29% for virus isolation. Our results indicate that NS1 is an excellent analyte for detection of DENV in Ae. aegypti and that the tested NS1 antigen kit provides a sensitive, rapid, and convenient test for DENV surveillance in mosquitoes.
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Affiliation(s)
- Natalia V Voge
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, USA.
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Rathakrishnan A, Sekaran SD. New development in the diagnosis of dengue infections. ACTA ACUST UNITED AC 2012; 7:99-112. [DOI: 10.1517/17530059.2012.718759] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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15
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García-Rejón JE, Loroño-Pino MA, Farfán-Ale JA, Flores-Flores LF, López-Uribe MP, Najera-Vazquez MDR, Nuñez-Ayala G, Beaty BJ, Eisen L. Mosquito infestation and dengue virus infection in Aedes aegypti females in schools in Merida, Mexico. Am J Trop Med Hyg 2011; 84:489-96. [PMID: 21363990 DOI: 10.4269/ajtmh.2011.10-0654] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
We determined abundance of Aedes aegypti mosquitoes and presence of dengue virus (DENV) in females collected from schools in Mérida, México, during 2008 and 2009. Backpack aspiration from 24 schools produced 468 females of Ae. aegypti and 1,676 females of another human biter, Culex quinquefasciatus. Ae. aegypti females were collected most commonly from classrooms followed by offices and bathrooms. Of these females, 24.7% were freshly fed. Examination of 118 pools of Ae. aegypti females (total of 415 females) for presence of DENV RNA produced 19 positive pools (16.1%). DENV-infected pools were detected from 11 (45.8%) of 24 schools and came from different room types, including classrooms, offices, and bathrooms. The overall rate of DENV infection per 100 Ae. aegypti females was 4.8. We conclude that schools in Mérida present a risk environment for students, teachers, and other personnel to be exposed to mosquitoes and bites of DENV-infected Ae. aegypti females.
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Affiliation(s)
- Julián E García-Rejón
- Laboratorio de Arbovirología, Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autónoma de Yucatán, Centro, Mérida, Yucatán, México.
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Dengue virus RNA purification from human plasma: a comparison of two techniques. Mol Biol Rep 2010; 38:4979-83. [PMID: 21161397 DOI: 10.1007/s11033-010-0642-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Accepted: 12/03/2010] [Indexed: 10/18/2022]
Abstract
Dengue virus RNA purification from human plasma is useful for research and clinical purposes. Dengue is endemic in the Espirito Santo State, Brazil, and it is progressively becoming a hard-to-control public health problem. Dengue virus types 1, 2 and 3 are currently found in Brazilian territory, and recently Dengue virus type 4 has been reported to enter Brazilian borders. This virus spreads rapidly during epidemic outbreaks, and thousands of patients are infected annually, with an underestimated number of deaths in consequence of hemorrhagic Dengue. Because this disease affects mainly developing countries, it is imperative that a robust, rapid and low cost method for viral nucleic acid purification is found. In this manuscript we compare two RNA extraction methods from serum/plasma of patients with clinical diagnosis of dengue. The QIAamp(®) UltraSens Virus Kit (Qiagen Inc., Valencia, USA) and the less expensive Chomczynski-Sacchi method were used to analyze a total of 47 samples. After nucleic acid purification, reverse transcription and polymerase chain reaction amplification with dengue virus type 2 specific primers were performed. This subtype is the most prevalent in our geographical location. Thirty-four samples were positive when RNA was extracted by the Chomczynski-Sacchi technique, whereas only 27 of these were positive when the QIAamp(®) UltraSens Virus Kit was used. These results favor the utilization of the more affordable technique for the purification of viral RNA, which is especially important for developing countries.
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Cartwright NH, Cassia LJ, Easton AJ, Morris AG. Detection of human papillomavirus in vulval carcinoma using semi-nested PCR and restriction enzyme typing: a rapid and sensitive technique. Mol Pathol 2010; 49:M236-9. [PMID: 16696082 PMCID: PMC408066 DOI: 10.1136/mp.49.4.m236] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Aims-To develop a highly sensitive technique for the reliable detection and typing of human papillomavirus (HPV) DNA in clinical tissue.Methods-A two step, semi-nested PCR was used with primers spanning the L1 region of the HPV genome and capable of detecting HPV DNA of all known HPV types. The clinical samples were typed by digestion of the 412 base pair PCR product with Rsa I, generating unique fragments for each HPV type. Thirteen samples were screened by this method, including nine vulval carcinoma samples and four wart samples from the penis and vulva.Results-Experiments using DNA extracted from HPV DNA positive cell lines-that is, CaSki (HPV type 16) and HeLa (HPV type 18) established that the technique could detect as few as 50 HPV copies and that the predicted Rsa I fragments from HPV types 16 and 18 were generated. The predicted 412 base pair fragment was observed for all 13 clinical samples subjected to semi-nested PCR. Rsa I digestion of the product of the second round of PCR permitted the positive identification of the HPV type in most cases.Conclusions-This technique provides an effective and rapid means of detecting HPV DNA, in most cases providing the HPV type. High risk HPV types were always detected in the nine vulval carcinoma samples analysed. The amount of tissue available from the biopsy specimens was small, confirming the sensitivity of the method.
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Affiliation(s)
- N H Cartwright
- Department of Biological Sciences, University of Warwick, Coventry CV4 7AL
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18
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A comparative retrospective study of RT-PCR-based liquid hybridization assay for early, definitive diagnosis of dengue. Trans R Soc Trop Med Hyg 2010; 104:279-82. [DOI: 10.1016/j.trstmh.2009.11.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 11/03/2009] [Accepted: 11/03/2009] [Indexed: 11/21/2022] Open
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19
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Bai Z, Liu L, Tu Z, Yao L, Liu J, Xu B, Tang B, Liu J, Wan Y, Fang M, Chen W. Real-time PCR for detecting circulating dengue virus in the Guangdong Province of China in 2006. J Med Microbiol 2009; 57:1547-1552. [PMID: 19018028 DOI: 10.1099/jmm.0.2008/003418-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Dengue virus (DENV) causes a wide range of diseases in humans, from the acute febrile illness dengue fever (DF) to life-threatening dengue haemorrhagic fever/dengue shock syndrome. We developed four real-time quantitative PCR assays for each serotype of DENV based on computational analysis. These assays had high sensitivity and specificity without cross-reactivity for the four serotypes. To evaluate the performance of these assays in detecting and typing the virus in clinical samples, we analysed 64 serum samples from Guangdong during 2006. The results showed that 71 % of those samples were positive by the DEN-1 assay. The DENV assay results, in agreement with the serological tests and sequencing analysis, showed that the pathogen resulting in the DF explosion in Guangdong in 2006 belonged to DEN-1. Compared to the serological assays, the real-time PCR assays that we developed were much more sensitive in the 1-3 days after onset of the symptoms.
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Affiliation(s)
- Zhijun Bai
- Guangzhou Medical Research Institute, Yan-Ling, Guangzhou 510507, PR China
| | - Licheng Liu
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 101300, PR China
| | - Zeng Tu
- College of Biotechnology, Southwest University, Chongqing 400715, PR China.,Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 101300, PR China
| | - Lisi Yao
- Chinese Academy of Inspection and Quarantine, Beijing 100025, PR China
| | - Jianwei Liu
- Guangzhou Medical Research Institute, Yan-Ling, Guangzhou 510507, PR China
| | - Bing Xu
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 101300, PR China
| | - Boheng Tang
- Guangzhou Medical Research Institute, Yan-Ling, Guangzhou 510507, PR China
| | - Jinhua Liu
- Guangzhou Medical Research Institute, Yan-Ling, Guangzhou 510507, PR China
| | - Yongji Wan
- College of Biotechnology, Southwest University, Chongqing 400715, PR China
| | - Meiyu Fang
- Guangzhou Medical Research Institute, Yan-Ling, Guangzhou 510507, PR China
| | - Weijun Chen
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 101300, PR China
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20
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Scholte EJ, Dijkstra E, Blok H, De Vries A, Takken W, Hofhuis A, Koopmans M, De Boer A, Reusken CBEM. Accidental importation of the mosquito Aedes albopictus into the Netherlands: a survey of mosquito distribution and the presence of dengue virus. MEDICAL AND VETERINARY ENTOMOLOGY 2008; 22:352-358. [PMID: 19120963 DOI: 10.1111/j.1365-2915.2008.00763.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In the summer of 2005, the Asian tiger mosquito, Aedes albopictus (Skuse) (Diptera: Culicidae) was found for the first time in the Netherlands. It was collected on the premises of several horticultural companies that import the ornamental plant Dracaena sanderiana (Sparagalus: Dracaenaceae [Agavaceae]), known as Lucky bamboo, from southern China, an area endemic for this mosquito species and for arboviruses transmitted by this vector. Here we report the results of a 1-year survey of the distribution and vector status of Ae. albopictus in Lucky bamboo nurseries in the Netherlands (July 2006-June 2007). As it had been established previously that the presence of this species was linked to the import of Lucky bamboo, the survey was conducted only on sites owned by relevant import companies. In total, 569 adult Ae. albopictus were collected with mosquito traps from 15 of the 17 (88%) glasshouses used by Lucky bamboo importers, none of which were found to be infected with dengue virus. On two occasions there was evidence that Ae. albopictus had escaped from the glasshouses, but, overall, there was no evidence that a population had become established in the greenhouses or elsewhere.
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Affiliation(s)
- E-J Scholte
- Dutch Plant Protection Service, Department of Entomology, Wageningen University, Wageningen, The Netherlands.
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21
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Singh K, Lale A, Eong Ooi E, Chiu LL, Chow VTK, Tambyah P, Koay ESC. A prospective clinical study on the use of reverse transcription-polymerase chain reaction for the early diagnosis of Dengue fever. J Mol Diagn 2007; 8:613-6; quiz 617-20. [PMID: 17065431 PMCID: PMC1876169 DOI: 10.2353/jmoldx.2006.060019] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Laboratory testing for dengue virus is used to confirm the diagnosis of dengue virus infection and to differentiate dengue from other febrile tropical illnesses. There are few data on the clinical use of reverse transcription-polymerase chain reaction (RT-PCR) for diagnosis of dengue virus infection. We prospectively evaluated 121 consecutive patients with possible dengue who had samples submitted for RT-PCR, IgM serology, and virus culture. Results were compared with the final discharge diagnosis. Semi-nested RT-PCR was performed using genus- and serotype-specific NS3 consensus primers. Results of 112 patients were available for the final analysis. The RT-PCR was positive in 40 of 62 patients with dengue. Patients who were RT-PCR-positive alone showed a mean of 4.4 days to RT-PCR positivity compared with 5.9 days in patients who were RT-PCR-negative and IgM serology-positive (P = 0.03, Mann-Whitney U-test). The sensitivity, specificity, negative predictive value, and positive predictive value were 70, 100, 84, and 100%, respectively, for samples analyzed within 5 days of illness onset. The RT-PCR also provided epidemiological data regarding the prevailing dengue virus serotypes: 25 with Den-2, eight with Den-3, and seven with Den-1 infection. We propose an algorithm of dengue testing that uses RT-PCR within 5 days of illness onset, whereas IgM capture enzyme-linked immunosorbent assay is preferred for those presenting later.
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Affiliation(s)
- Kamaljit Singh
- Rush University Medical Center, 600 S. Paulina Ave., ACC Suite 140, Chicago, IL 60612, USA.
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22
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Abstract
Dengue diagnosis was one of the topics discussed at the symposium 'The Global Threat of Dengue - Desperately Seeking Solutions' organized during the 10th International Congress of Infectious Diseases held in Singapore in 2002. In this paper, a review is presented focusing on the main advances, problems and challenges of dengue diagnosis.IgM capture ELISA, virus isolation in mosquito cell lines and live mosquitoes, dengue specific monoclonal antibodies and PCR have all represented major advances in dengue diagnosis. However, an appropriate rapid, early and accessible diagnostic method useful both for epidemiological surveillance and clinical diagnosis is still needed. Also, tools that suggest a prognosis allowing for better management are also needed. Finally, laboratory infrastructure, technical expertise and research capacity must be improved in endemic countries in order to positively influence dengue surveillance, clinical case management and the development of new approaches to dengue control.
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Affiliation(s)
- María G Guzmán
- Virology Department, PAHO/WHO Collaborating Center for Viral Diseases, 'Pedro Kouri;' Tropical Medicine Institute, Autopista Novia del Mediodi;a, Km 6, Ciudad Habana, Cuba.
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23
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Raengsakulrach B, Nisalak A, Maneekarn N, Yenchitsomanus PT, Limsomwong C, Jairungsri A, Thirawuth V, Green S, Kalayanarooj S, Suntayakorn S, Sittisombut N, Malasit P, Vaughn D. Comparison of four reverse transcription-polymerase chain reaction procedures for the detection of dengue virus in clinical specimens. J Virol Methods 2002; 105:219-32. [PMID: 12270655 DOI: 10.1016/s0166-0934(02)00104-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The sensitivity of dengue virus identification by mosquito inoculation and four reverse transcription-polymerase chain reaction (RT-PCR) procedures (Am. J. Trop. Med. Hyg. 45 (1991) 418 (H); J. Clin. Microbiol. 29 (1991) 2107 (M); J. Clin. Microbiol. 30 (1992) 545 (L); and Southeast Asian J. Trop. Med. Public Health 27 (1996) 228 (Y)) were compared using coded clinical specimens derived from areas in Thailand where all four dengue serotypes circulate. The sensitivity of virus detection in serologically confirmed dengue cases was 54, 52, 60, 79, and 80% for mosquito inoculation, procedures H, M, L and Y, respectively. In comparison to clinical specimens which yielded virus isolates by mosquito inoculation, there was relatively low sensitivity in detecting each of the four dengue serotypes by PCR: procedure H-dengue 4 (25%), procedure M-dengue 3 (73%), procedure L-dengue 1 (70%), and procedure Y-dengue 1 (79%). Dengue virus was detectable by RT-PCR for more days of illness and in the presence of dengue-specific antibody when compared to virus isolated in mosquitoes. Procedures L and Y were more sensitive than mosquito inoculation or procedures H and M in detecting all four dengue serotypes in clinical specimens and may be the RT-PCR methods of choice for virus surveillance or research use.
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Affiliation(s)
- Boonyos Raengsakulrach
- Department of Virology, US Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
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Chung YK, Pang FY. Dengue virus infection rate in field populations of female Aedes aegypti and Aedes albopictus in Singapore. Trop Med Int Health 2002; 7:322-30. [PMID: 11952948 DOI: 10.1046/j.1365-3156.2002.00873.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We developed a single-step reverse transcription-polymerase chain reaction (RT-PCR) followed by a semi-nested PCR using an upstream consensus primer and four type-specific primers within the non-structural protein gene (NS3) of dengue viruses to type dengue viruses in field populations of female Aedes mosquitoes. This yielded diagnostic fragments of 169, 362, 265 and 426 base pairs for dengue virus types 1, 2, 3 and 4, respectively. From 1997 to 2000, 54 (6.9%) of 781 Aedes aegypti and 67 (2.9%) of 2256 Aedes albopictus screened were positive for dengue viruses, with a declining trend. The most common dengue virus type detected in the Aedes mosquitoes was dengue-1. Details on the change of one serotype to another in the mosquito population over three consecutive years are discussed.
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Affiliation(s)
- Youne Kow Chung
- Vector Control & Research Department, Ministry of the Environment, Singapore.
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25
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Singh S, Chow VT, Chan KP, Ling AE, Poh CL. RT-PCR, nucleotide, amino acid and phylogenetic analyses of enterovirus type 71 strains from Asia. J Virol Methods 2000; 88:193-204. [PMID: 10960707 DOI: 10.1016/s0166-0934(00)00185-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A specific and sensitive method based on RT-PCR was developed to detect enterovirus 71 (EV71) from patients with hand, foot and mouth disease, myocarditis, aseptic meningitis and acute flaccid paralysis. RT-PCR primers from conserved parts of the VP1 capsid gene were designed on the basis of good correlation with sequences of EV71 strains. These primers successfully amplified 44 strains of EV71 including 34 strains isolated from Singapore in 1997 and 1998, eight strains from Malaysia isolated in 1997 and 1998, one Japanese strain and the neurovirulent strain EV71/7423/MS/87. RT-PCR of 30 strains of other enteroviruses including coxsackievirus A and B, and echoviruses failed to give any positive amplicons. Hence, RT-PCR with these primers showed 100% correlation with serotyping. Direct sequencing of the RT-PCR products of 20 EV71 strains revealed a distinct cluster with two major subgroups, thus enabling genetic typing of the viruses. The genetic heterogeneity of these strains culminated in amino acid substitutions within the VP1, VP2 and VP3 regions. The sequencing of a 2.9 kb fragment comprising the capsid region and the major part of 5' UTR of two Singapore strains revealed that they belonged to a group distinct from the prototype EV71/BrCr strain and the EV71/7423/MS/87 strain. The dendrogram generated from 341 bp fragments within the VP1 region revealed that the strains of Singapore, Malaysia and Taiwan belong to two entirely different EV71 genogroups, distinct from the three genogroups identified in another recent study.
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Affiliation(s)
- S Singh
- Programme in Infectious Diseases, Department of Microbiology, Faculty of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117597
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26
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Muir P, Kämmerer U, Korn K, Mulders MN, Pöyry T, Weissbrich B, Kandolf R, Cleator GM, van Loon AM. Molecular typing of enteroviruses: current status and future requirements. The European Union Concerted Action on Virus Meningitis and Encephalitis. Clin Microbiol Rev 1998; 11:202-27. [PMID: 9457433 PMCID: PMC121380 DOI: 10.1128/cmr.11.1.202] [Citation(s) in RCA: 190] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Human enteroviruses have traditionally been typed according to neutralization serotype. This procedure is limited by the difficulty in culturing some enteroviruses, the availability of antisera for serotyping, and the cost and technical complexity of serotyping procedures. Furthermore, the impact of information derived from enterovirus serotyping is generally perceived to be low. Enteroviruses are now increasingly being detected by PCR rather than by culture. Classical typing methods will therefore no longer be possible in most instances. An alternative means of enterovirus typing, employing PCR in conjunction with molecular genetic techniques such as nucleotide sequencing or nucleic acid hybridization, would complement molecular diagnosis, may overcome some of the problems associated with serotyping, and would provide additional information regarding the epidemiology and biological properties of enteroviruses. We argue the case for developing a molecular typing system, discuss the genetic basis of such a system, review the literature describing attempts to identify or classify enteroviruses by molecular methods, and suggest ways in which the goal of molecular typing may be realized.
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Affiliation(s)
- P Muir
- Department of Virology, United Medical School of Guy's Hospital, London, United Kingdom.
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Chow VT, Yong RY, Ngoh BL, Chan YC. Automated type specific ELISA probe detection of amplified NS3 gene products of dengue viruses. J Clin Pathol 1997; 50:346-9. [PMID: 9215155 PMCID: PMC499889 DOI: 10.1136/jcp.50.4.346] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
AIM To apply an automated system of nucleic acid hybridisation coupled with the enzyme linked immunosorbent assay (ELISA) for the type specific detection of amplification products of dengue viruses. METHODS Non-structural 3 (NS3) gene targets of reference strains of all four dengue and other flaviviruses, as well as dengue patient viraemic sera, were subjected to reverse transcription and polymerase chain reaction using consensus and dengue type specific primers and digoxigenin-11-dUTP label incorporation. The amplification products were detected by biotinylated type specific primers which served as ELISA capture probes bound to streptavidin coated tubes. RESULTS Significantly high spectrophotometric absorbance readings were obtained by hybridisation of the consensus and seminested amplification products of all four dengue viruses with their respective capture probes. In contrast, extremely low absorbances were observed for consensus products of Japanese encephalitis, yellow fever, and Kunjin viruses, which served as negative controls. These ELISA data correlated well with agarose gel electrophoresis of dengue type specific amplified products of diagnostic sizes. CONCLUSIONS The combination of in vitro amplification and antibody based detection offers rapid, type specific, high throughput, and gel-free detection of amplified products of dengue viruses.
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Affiliation(s)
- V T Chow
- Department of Microbiology, Faculty of Medicine, National University of Singapore, Republic of Singapore
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28
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Chow VT, Yong R, Chan YC. Sequence analyses of NS3 genes of recent Pakistan and Singapore strains of dengue virus types 1 and 2. RESEARCH IN VIROLOGY 1997; 148:17-20. [PMID: 9017828 DOI: 10.1016/s0923-2516(97)81907-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- V T Chow
- Department of Microbiology, Faculty of Medicine, National University of Singapore, Singapore
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Chan YC, Salahuddin NI, Khan J, Tan HC, Seah CL, Li J, Chow VT. Dengue haemorrhagic fever outbreak in Karachi, Pakistan, 1994. Trans R Soc Trop Med Hyg 1995; 89:619-20. [PMID: 8594672 DOI: 10.1016/0035-9203(95)90412-3] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Affiliation(s)
- Y C Chan
- Department of Microbiology, National University of Singapore, Singapore
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