RESUMO
The emergence of chikungunya virus in the Americas means the affected population is at risk of developing severe, chronic, rheumatologic disease, even months after acute infection. Accurate diagnostic methods for past infections are essential for differential diagnosis and consequence management. This study evaluated three commercially-available chikungunya Immunoglobulin G immunoassays by comparing them to an in-house Enzyme-Linked ImmunoSorbent Assay conducted by the Centers for Disease Control and Prevention (Atlanta, Georgia, United States). Results showed sensitivity and specificity values ranging from 92.8% - 100% and 81.8% - 90.9%, respectively, with a significant number of false-positives ranging from 12.5% - 22%. These findings demonstrate the importance of evaluating commercial kits, especially regarding emerging infectious diseases whose medium and long-term impact on the population is unclear.
Assuntos
Anticorpos Antivirais/sangue , Febre de Chikungunya/sangue , Febre de Chikungunya/diagnóstico , Vírus Chikungunya/imunologia , Imunoglobulina G/sangue , Humanos , ImunoensaioRESUMO
The emergence of chikungunya virus in the Americas means the affected population is at risk of developing severe, chronic, rheumatologic disease, even months after acute infection. Accurate diagnostic methods for past infections are essential for differential diagnosis and consequence management. This study evaluated three commercially-available chikungunya Immunoglobulin G immunoassays by comparing them to an in-house Enzyme-Linked ImmunoSorbent Assay conducted by the Centers for Disease Control and Prevention (Atlanta, Georgia, United States). Results showed sensitivity and specificity values ranging from 92.8% – 100% and 81.8% – 90.9%, respectively, with a significant number of false-positives ranging from 12.5% – 22%. These findings demonstrate the importance of evaluating commercial kits, especially regarding emerging infectious diseases whose medium and long-term impact on the population is unclear.
Como consecuencia de la aparición del virus del chikungunya en las Américas, la población afectada corre el riesgo de padecer reumatismos crónicos graves, aun meses después de la infección aguda. Es fundamental contar con métodos precisos para diagnosticar los antecedentes de la infección a fin de elaborar un diagnóstico diferencial y abordar las manifestaciones de la fase crónica. Se han estudiado tres inmunoensayos comercializados de detección de inmunoglobulinas G para el diagnóstico del chikungunya, comparándolos con el enzimoinmunoanálisis de adsorción (ELISA) propio. Los resultados señalan valores de sensibilidad del 92,8% al 100% y de especificidad del 81,8% al 90,9%, así como un número significativo de falsos positivos, de entre el 12,5% y el 22%.
Assuntos
Vírus Chikungunya , Kit de Reagentes para Diagnóstico , Imunoensaio , Técnicas Imunoenzimáticas , Imunoensaio de Fluorescência por Polarização , Região do Caribe , América , Vírus Chikungunya , Kit de Reagentes para Diagnóstico , Imunoensaio , Técnicas Imunoenzimáticas , Imunoensaio de Fluorescência por PolarizaçãoRESUMO
ABSTRACT The emergence of chikungunya virus in the Americas means the affected population is at risk of developing severe, chronic, rheumatologic disease, even months after acute infection. Accurate diagnostic methods for past infections are essential for differential diagnosis and consequence management. This study evaluated three commercially-available chikungunya Immunoglobulin G immunoassays by comparing them to an in-house Enzyme-Linked ImmunoSorbent Assay conducted by the Centers for Disease Control and Prevention (Atlanta, Georgia, United States). Results showed sensitivity and specificity values ranging from 92.8% - 100% and 81.8% - 90.9%, respectively, with a significant number of false-positives ranging from 12.5% - 22%. These findings demonstrate the importance of evaluating commercial kits, especially regarding emerging infectious diseases whose medium and long-term impact on the population is unclear.(AU)
RESUMEN Como consecuencia de la aparición del virus del chikungunya en las Américas, la población afectada corre el riesgo de padecer reumatismos crónicos graves, aun meses después de la infección aguda. Es fundamental contar con métodos precisos para diagnosticar los antecedentes de la infección a fin de elaborar un diagnóstico diferencial y abordar las manifestaciones de la fase crónica. Se han estudiado tres inmunoensayos comercializados de detección de inmunoglobulinas G para el diagnóstico del chikungunya, comparándolos con el enzimoinmunoanálisis de adsorción (ELISA) propio. Los resultados señalan valores de sensibilidad del 92,8% al 100% y de especificidad del 81,8% al 90,9%, así como un número significativo de falsos positivos, de entre el 12,5% y el 22%.(AU)
Assuntos
Humanos , Kit de Reagentes para Diagnóstico , Imunoglobulina G , Vírus Chikungunya/isolamento & purificação , Imunoensaio de Fluorescência por Polarização , Técnicas Imunoenzimáticas , Febre de Chikungunya/diagnóstico , América , Região do CaribeRESUMO
OBJECTIVE: To differentiate exposure to the newly introduced chikungunya virus from exposure to endemic dengue virus and other pathogens in Haiti. METHODS: We used a multiplex bead assay to detect immunoglobulin G (IgG) responses to a recombinant chikungunya virus antigen, two dengue virus-like particles and three recombinant Plasmodium falciparum antigens. Most (217) of the blood samples investigated were collected longitudinally, from each of 61 children, between 2011 and 2014 but another 127 were collected from a cross-sectional sample of children in 2014. FINDINGS: Of the samples from the longitudinal cohort, none of the 153 collected between 2011 and 2013 but 78.7% (48/61) of those collected in 2014 were positive for IgG responses to the chikungunya virus antigen. In the cross-sectional sample, such responses were detected in 96 (75.6%) of the children and occurred at similar prevalence across all age groups. In the same sample, responses to malarial antigen were only detected in eight children (6.3%) but the prevalence of IgG responses to dengue virus antigens was 60.6% (77/127) overall and increased steadily with age. Spatial analysis indicated that the prevalence of IgG responses to the chikungunya virus and one of the dengue virus-like particles decreased as the sampling site moved away from the city of Léogâne and towards the ocean. CONCLUSION: Serological evidence indicates that there had been a rapid and intense dissemination of chikungunya virus in Haiti. The multiplex bead assay appears to be an appropriate serological platform to monitor the seroprevalence of multiple pathogens simultaneously.
Assuntos
Febre de Chikungunya , Dengue , Exposição Ambiental , Malária , Adolescente , Febre de Chikungunya/diagnóstico , Febre de Chikungunya/epidemiologia , Vírus Chikungunya/isolamento & purificação , Criança , Pré-Escolar , Estudos Transversais , Dengue/diagnóstico , Dengue/epidemiologia , Exposição Ambiental/estatística & dados numéricos , Feminino , Haiti/epidemiologia , Humanos , Estudos Longitudinais , Malária/diagnóstico , Malária/epidemiologia , Masculino , Plasmodium falciparum/isolamento & purificaçãoRESUMO
West Nile virus ecology has yet to be rigorously investigated in the Caribbean Basin. We identified a transmission focus in Puerto Barrios, Guatemala, and established systematic monitoring of avian abundance and infection, seroconversions in domestic poultry, and viral infections in mosquitoes. West Nile virus transmission was detected annually between May and October from 2005 to 2008. High temperature and low rainfall enhanced the probability of chicken seroconversions, which occurred in both urban and rural sites. West Nile virus was isolated from Culex quinquefasciatus and to a lesser extent, from Culex mollis/Culex inflictus, but not from the most abundant Culex mosquito, Culex nigripalpus. A calculation that combined avian abundance, seroprevalence, and vertebrate reservoir competence suggested that great-tailed grackle (Quiscalus mexicanus) is the major amplifying host in this ecosystem. West Nile virus transmission reached moderate levels in sentinel chickens during 2007, but less than that observed during outbreaks of human disease attributed to West Nile virus in the United States.
Assuntos
Ecossistema , Clima Tropical , Vírus do Nilo Ocidental/fisiologia , Animais , Aves/virologia , Culex/virologia , Guatemala , Humanos , Insetos Vetores , Vírus do Nilo Ocidental/isolamento & purificaçãoRESUMO
West Nile virus (WNV) is an emerging mosquito-borne flavivirus, which has rapidly spread and is currently widely distributed. Therefore, efforts for WNV early detection and ecological surveillance of this disease agent have been increased around the world. Although virus isolation is known to be the standard method for detection and identification of viruses, the use of RT-PCR assays as routine laboratory tests provides a rapid alterative suitable for the detection of viral RNA on field-collected samples. A method for WNV RNA genome detection in field-collected mosquitoes is presented in this chapter. This method has been designed for virus surveillance in tropical regions endemic for other flaviviruses. Reverse Transcriptase-PCR (RT-PCR) assays, both standard and real time, to detect WNV and other flaviviruses are described. A first screening for flavivirus RNA detection is performed using a conventional RT-PCR with two different sets of flavivirus consensus primers. Mosquito samples are then tested for WNV RNA by a real-time (TaqMan) RT-PCR assay. Sample preparation and RNA extraction procedures are also described.
Assuntos
Culicidae/virologia , RNA Viral/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Vírus do Nilo Ocidental/isolamento & purificação , Animais , Culicidae/genética , Primers do DNA , Flavivirus/genética , Humanos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/instrumentação , Clima Tropical , Vírus do Nilo Ocidental/genéticaAssuntos
Infecções por Flavivirus/genética , Flavivirus/genética , Flavivirus/isolamento & purificação , Adulto , Equador , Flavivirus/classificação , Flavivirus/patogenicidade , Infecções por Flavivirus/sangue , Infecções por Flavivirus/diagnóstico , Humanos , Masculino , Militares , Dados de Sequência MolecularRESUMO
St. Louis encephalitis (SLE) and West Nile (WN) flaviviruses are genetically closely related and cocirculate in the United States. Virus neutralization tests provide the most specific means for serodiagnosis of infections with these viruses. However, use of wild-type SLE and WN viral strains for laboratory testing is constrained by the biocontainment requirements. We constructed two highly attenuated yellow fever (YF) virus chimeras that contain the premembrane-envelope (prM-E) protein genes from the virulent MSI-7 (isolated in the United States) or the naturally attenuated CorAn9124 (Argentina) SLE strains. The YF/SLE (CorAn version) virus and the previously constructed YF/WN chimera were shown to specifically distinguish between confirmed human SLE and WN cases in a virus neutralization test using patient sera. These chimeras have the potential for use as diagnostic reagents and vaccines against SLE and WN.
Assuntos
Vírus da Encefalite de St. Louis/isolamento & purificação , Encefalite de St. Louis/prevenção & controle , Genes Virais/genética , Vacinas Virais/síntese química , Febre Amarela/prevenção & controle , Vírus da Febre Amarela/isolamento & purificação , Sequência de Aminoácidos , Animais , Argentina/epidemiologia , Culex/virologia , Vírus da Encefalite de St. Louis/genética , Vírus da Encefalite de St. Louis/imunologia , Encefalite de St. Louis/epidemiologia , Encefalite de St. Louis/transmissão , Humanos , Camundongos , Dados de Sequência Molecular , Proteínas Recombinantes de Fusão/genética , Alinhamento de Sequência , Estados Unidos/epidemiologia , Vacinas Virais/uso terapêutico , Febre Amarela/epidemiologia , Febre Amarela/transmissão , Vírus da Febre Amarela/genética , Vírus da Febre Amarela/imunologiaRESUMO
Because the potential urban yellow fever (YF) mosquito vectors Aedes aegypti and Ae. albopictus are at historical highs in Brazil, both in terms of density and geographical range, we assessed the risk of an urban YF epidemic in Brazil. We evaluated and confirmed in a laboratory setting the vector competence of Brazilian Ae. aegypti for a currently circulating strain of YF virus, and investigated the potential for Brazilian Ae. albopictus to transmit YF.