RESUMO
BackgroundNeurotropic arboviruses are increasingly recognised as causative agents of neurological disease in Europe but underdiagnosis is still suspected. Capability for accurate diagnosis is a prerequisite for adequate clinical and public health response.AimTo improve diagnostic capability in EVD-LabNet laboratories, we organised an external quality assessment (EQA) focusing on molecular detection of Toscana (TOSV), Usutu (USUV), West Nile (WNV) and tick-borne encephalitis viruses (TBEV).MethodsSixty-nine laboratories were invited. The EQA panel included two WNV RNA-positive samples (lineages 1 and 2), two TOSV RNA-positive samples (lineages A and B), one TBEV RNA-positive sample (Western subtype), one USUV RNA-positive sample and four negative samples. The EQA focused on overall capability rather than sensitivity of the used techniques. Only detection of one, clinically relevant, concentration per virus species and lineage was assessed.ResultsThe final EQA analysis included 51 laboratories from 35 countries; 44 of these laboratories were from 28 of 31 countries in the European Union/European Economic Area (EU/EEA). USUV diagnostic capability was lowest (28 laboratories in 18 countries), WNV detection capacity was highest (48 laboratories in 32 countries). Twenty-five laboratories were able to test the whole EQA panel, of which only 11 provided completely correct results. The highest scores were observed for WNV and TOSV (92%), followed by TBEV (86%) and USUV (75%).ConclusionWe observed wide variety in extraction methods and RT-PCR tests, showing a profound absence of standardisation across European laboratories. Overall, the results were not satisfactory; capacity and capability need to be improved in 40 laboratories.
Assuntos
Vírus da Encefalite Transmitidos por Carrapatos/genética , Flavivirus/genética , Laboratórios/normas , Técnicas de Diagnóstico Molecular/normas , Garantia da Qualidade dos Cuidados de Saúde/normas , Vírus da Febre do Flebótomo Napolitano/genética , Vírus da Encefalite Transmitidos por Carrapatos/isolamento & purificação , Encefalite Transmitida por Carrapatos/diagnóstico , Flavivirus/isolamento & purificação , Infecções por Flavivirus/diagnóstico , Humanos , Febre por Flebótomos/diagnóstico , Controle de Qualidade , Vírus da Febre do Flebótomo Napolitano/isolamento & purificação , Febre do Nilo Ocidental/virologia , Vírus do Nilo Ocidental/imunologiaRESUMO
The threat of West Nile virus (WNV) epidemics with increasingly severe neuroinvasive infections demands the development and licensing of effective vaccines. To date, vaccine candidates based on inactivated, live-attenuated, or chimeric virus, and viral DNA and WNV protein subunits have been developed. Some have been approved for veterinary use or are under clinical investigation, yet no vaccine has been licensed for human use. Reaching the milestone of a commercialized human vaccine, however, may largely depend on the economics of vaccine production. Analysis suggests that currently only novel low-cost production technologies would allow vaccination to outcompete the cost of surveillance and clinical treatment. Here, we review progress using plants to address the economic challenges of WNV vaccine production. The advantages of plants as hosts for vaccine production in cost, speed and scalability, especially those of viral vector-based transient expression systems, are discussed. The progress in developing WNV subunit vaccines in plants is reviewed within the context of their expression, characterization, downstream processing, and immunogenicity in animal models. The development of vaccines based on enveloped and non-enveloped virus-like particles is also discussed. These advancements suggest that plants may provide a production platform that offers potent, safe and affordable human vaccines against WNV.
Assuntos
Plantas/genética , Vacinas contra o Vírus do Nilo Ocidental/biossíntese , Vacinas contra o Vírus do Nilo Ocidental/economia , Animais , Humanos , Plantas/metabolismo , Plantas/virologia , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/imunologia , Febre do Nilo Ocidental/prevenção & controle , Vacinas contra o Vírus do Nilo Ocidental/efeitos adversos , Vírus do Nilo Ocidental/genética , Vírus do Nilo Ocidental/imunologiaRESUMO
We report four cases of West Nile virus (WNV) transmission following a single multiorgan donation in north-eastern Italy. The transmissions were promptly detected by local transplant centres. The donor had been tested for WNV by nucleic acid amplification test (NAT) prior to transplantation and was negative. There were no detected errors in the nationally implemented WNV safety protocols.
Assuntos
Transplante de Rim/efeitos adversos , Febre do Nilo Ocidental/transmissão , Vírus do Nilo Ocidental/isolamento & purificação , Anticorpos Antivirais/sangue , Atenção à Saúde/organização & administração , Seleção do Doador/normas , Humanos , Itália , Técnicas Microbiológicas/normas , Técnicas de Amplificação de Ácido Nucleico/normas , Doadores de Tecidos , Febre do Nilo Ocidental/sangue , Febre do Nilo Ocidental/prevenção & controle , Febre do Nilo Ocidental/virologia , Vírus do Nilo Ocidental/imunologiaRESUMO
Blood samples from 145 Black-crowned Night-heron (Nycticorax nycticorax, BCNH) chicks (mean age 3 weeks) were taken from four island colonies (Goose (2004), Canarsie Pol (2005), Hoffman (2004 and 2005) and North Brother (2004 and 2005)) in New York Harbor in 2004 and 2005 to establish baseline health reference ranges for this species and to compare health indices of birds reared on different islands. Packed cell volume (PCV) and total solids (TS) did not differ among islands in either year. Herons raised on Hoffman Island in 2004 had lower white blood cell count (WBC), and higher activities of creatine phosphokinase (CPK), lactate dehydrogenase (LDH), aspartate amino transferase (AST), higher concentrations of potassium (K) and phosphorous (PHOS) and lower liver derived proteins (TP, prealbumin, albumin, alpha 1 globulins, alpha 2 globulins, beta globulins and gamma globulins) compared to herons from Goose and North Brother Islands. These changes suggest compromised health in chicks reared on Hoffman Island in 2004. On Hoffman in 2005, these biochemical analytes did not differ from concentrations and enzyme activities measured from birds on other islands. Although no single etiology can explain these extensive changes, it is likely that exposure to contaminants at foraging sites used by birds nesting on Hoffman and/or changes in prey availability and abundance causing birds to forage in different locations between years, led to differences measured in blood-based health indices. Avian health assessments coupled with foraging ecology serve as an excellent method for evaluating ecosystem health of the New York Harbor estuary system.
Assuntos
Aves/fisiologia , Ecossistema , Saúde , Animais , Anticorpos Antifúngicos/sangue , Anticorpos Antivirais/sangue , Aspergillus/imunologia , Biomarcadores/sangue , Aves/imunologia , Aves/microbiologia , Aves/virologia , Geografia , Hematócrito , Contagem de Leucócitos , Cidade de Nova Iorque , Rios , Testes Sorológicos , Vírus do Nilo Ocidental/imunologiaRESUMO
Infection with West Nile virus (WNV) causes fatal encephalitis in immunocompromised animals. Previous studies in mice have established that T cell protection is required for clearance of WNV infection from tissues and preventing viral persistence. The current study assessed whether specific WNV peptide epitopes could elicit a cytotoxic T lymphocyte (CTL) response capable of protecting against virus infection. Hidden Markov model analysis was used to identify WNV-encoded peptides that bound the MHC class I proteins K(b) or D(b). Of the 35 peptides predicted to bind MHC class I molecules, one immunodominant CTL recognition peptide was identified in each of the envelope and non-structural protein 4B genes. Addition of these but not control peptides to CD8(+) T cells from WNV-infected mice induced IFN-gamma production. CTL clones that were generated ex vivo lysed peptide-pulsed or WNV-infected target cells in an antigen-specific manner. Finally, adoptive transfer of a mixture of envelope- and non-structural protein 4B-specific CTL to recipient mice protected against lethal WNV challenge. Based on this, we conclude that CTL responses against immundominant WNV epitopes confer protective immunity and thus should be targets for inclusion in new vaccines.
Assuntos
Antígenos Virais/imunologia , Linfócitos T Citotóxicos/imunologia , Febre do Nilo Ocidental/imunologia , Vírus do Nilo Ocidental/imunologia , Transferência Adotiva , Algoritmos , Sequência de Aminoácidos , Animais , Antígenos Virais/genética , Antígenos Virais/isolamento & purificação , Antígenos de Histocompatibilidade Classe I/imunologia , Epitopos Imunodominantes/genética , Epitopos Imunodominantes/imunologia , Epitopos Imunodominantes/isolamento & purificação , Cadeias de Markov , Camundongos , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/imunologia , Proteínas do Envelope Viral/isolamento & purificação , Febre do Nilo Ocidental/prevenção & controleRESUMO
Viral infections have been important complications in the transplant procedure from the early days of stem-cell transplantation, causing significant morbidity and mortality. It is important for the management of patients to assess the risk for viral infections that might develop after the stem-cell transplantation. This can be exemplified by cytomegalovirus (CMV) and other herpesviruses, but risk assessment is also important for other viral infections. The aim of this review is to describe current knowledge regarding recipient and donor serological status for viral infections.
Assuntos
Transplante de Células-Tronco Hematopoéticas , Viroses/imunologia , Síndrome da Imunodeficiência Adquirida/imunologia , Animais , Anticorpos Antivirais/análise , Infecções por Citomegalovirus/etiologia , Infecções por Citomegalovirus/imunologia , Deltaretrovirus/imunologia , Doença Enxerto-Hospedeiro/imunologia , Doença Enxerto-Hospedeiro/prevenção & controle , Doença Enxerto-Hospedeiro/virologia , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Herpes Simples/imunologia , Herpesvirus Humano 3/imunologia , Herpesvirus Humano 4/imunologia , Humanos , Vírus Sinciciais Respiratórios/imunologia , Medição de Risco , Doadores de Tecidos , Viroses/etiologia , Vírus do Nilo Ocidental/imunologiaRESUMO
The Ferlo area (north-central Senegal) is characterized by a system of temporary ponds favorable to arboviruses among which West Nile fever (WNF) was already identified. During the rainy season in 2003, a serological study was undertaken on horses to assess the activity of the WNF virus (WNFV) in Barkedji (Ferlo). The observed serological prevalence rate was 78.3% for neutralizing antibodies, with a 95% confidence interval (CI) of [64.0, 92.7]. This prevalence rate significantly increased with age (P = 10(-5)). This study confirmed that WNF was endemic in the Ferlo. The transmission risks depended on the introduction of the WNFV in the ecosystem--probably with migrating birds, on its amplification in hosts and on the vector-population dynamic. Further studies are needed to investigate how the cycle is initiated in Barkedji at the beginning of the rainy season and the impact of climatic variations on the risk of transmission of WNF. A surveillance system should be implemented: (a) to assess the clinical impact of the WNF on human and equine populations, (b) to provide an early detection of virulent strains, and (c) to assess the risk of WNF transmission to disease-free ecosystems via migrating birds.
Assuntos
Anticorpos Antivirais/sangue , Doenças dos Cavalos/epidemiologia , Febre do Nilo Ocidental/veterinária , Vírus do Nilo Ocidental/imunologia , Fatores Etários , Animais , Análise por Conglomerados , Doenças dos Cavalos/transmissão , Cavalos , Humanos , Insetos Vetores/virologia , Testes de Neutralização/veterinária , Estações do Ano , Senegal/epidemiologia , Vigilância de Evento Sentinela/veterinária , Estudos Soroepidemiológicos , Febre do Nilo Ocidental/epidemiologia , Febre do Nilo Ocidental/transmissão , ZoonosesRESUMO
Accurate detection of West Nile virus (WNV) in corvids is essential for monitoring the spread of virus during the mosquito season. Viremia in corvids is very high, with titers approaching 10(8) viral particles/ml. In the presence of such marked viremia, the sensitivity of real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis is unnecessary, and more cost-effective methods should be assessed. To this end, antigen-capture ELISA (ACE) and immunohistochemical (IHC) assays were evaluated. Skin, cloacal swab specimens, and feathers from corvids were tested by use of ACE, and results were compared with results obtained from use of real-time RT-PCR analysis. Of the 3 sample types, skin gave the best sensitivity (98%) and specificity (100%). Skin, brain, kidney, and spleen from corvids were analyzed by IHC, and results were compared with real-time RT-PCR results. Kidney and spleen were more often positive by use of IHC than were brain and skin tissue; however, IHC did not perform as well as ACE in the identification of virus-positive birds. Results of this study support the use of a skin sample in an ACE format as an effective surveillance method for corvids.
Assuntos
Doenças das Aves/diagnóstico , Corvos , Ensaio de Imunoadsorção Enzimática/veterinária , Imuno-Histoquímica/veterinária , Febre do Nilo Ocidental/veterinária , Vírus do Nilo Ocidental/isolamento & purificação , Animais , Antígenos Virais/análise , Doenças das Aves/virologia , Encéfalo/virologia , Cloaca/virologia , Análise Custo-Benefício , Ensaio de Imunoadsorção Enzimática/economia , Ensaio de Imunoadsorção Enzimática/métodos , Plumas/virologia , Imuno-Histoquímica/economia , Imuno-Histoquímica/métodos , Rim/virologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa/economia , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Pele/virologia , Baço/virologia , Febre do Nilo Ocidental/diagnóstico , Febre do Nilo Ocidental/virologia , Vírus do Nilo Ocidental/genética , Vírus do Nilo Ocidental/imunologiaRESUMO
To address the emerging threat of West Nile virus (WNV) to the blood supply, Canadian Blood Services (CBS) made a series of policy decisions that were either similar to those adopted in the United States or more stringent than policies formulated in the United States at the same time. More stringent Canadian policies included the development of an in-house WNV RNA assay, the stockpiling of frozen plasma components in the winter for transfusion in WNV-affected areas in the summer, a special recruitment campaign for red blood cell collections before the start of the 2003 WNV season, and an inventory exchange (ie, WNV-tested for untested red blood cells) initiated 2 weeks after the onset of WNV screening, as well as the implementation of targeted individual-donation WNV testing on August 2, 2004, in the absence of any positive donors or clinical cases of WNV infection in Canada. The general principles that guided CBS decision making with regard to WNV safety included application of the precautionary principle, harmonization with policies in the United States, a consideration of logistic issues, compliance with Health Canada requests, responsiveness to public expectations about transfusion safety, and transparency in decision making with timely communication to stakeholders. Before implementing WNV blood safety policies, CBS assessed their impact on blood availability. When policies were implemented, data were obtained quickly to ensure that the prior impact assessments were accurate. This review discusses the guiding principles affecting CBS policy development and compares CBS WNV safety policies to policies adopted in the United States.
Assuntos
Bancos de Sangue/normas , Transfusão de Sangue/normas , Sangue/virologia , Segurança , Febre do Nilo Ocidental/prevenção & controle , Vírus do Nilo Ocidental , Anticorpos Antivirais/sangue , Bancos de Sangue/legislação & jurisprudência , Doadores de Sangue , Coleta de Amostras Sanguíneas/normas , Canadá , Política de Saúde , Humanos , Reação Transfusional , Estados Unidos , Febre do Nilo Ocidental/transmissão , Vírus do Nilo Ocidental/imunologiaRESUMO
The non-specific background reaction produced in avidin-biotin-based immunohistochemistry, particularly after harsh antigen retrieval procedures, has promoted the use of non-avidin-biotin systems, yet there are few reports comparing the performance of non-avidin-biotin, polymer-based methods. In this study we compare two of these methods, ENVISION+trade mark and ImmPRESS, in animal tissues. We examined the immunoreactivity of 18 antigens in formalin-fixed, paraffin-embedded tissues. Antigens were located in the cytoplasmic membrane (CD11d, CD18 and CD79a), cytoplasm (calretinin, COX-1, COX-2, Glut-1, HepPar 1, KIT, Melan A, tryptase and uroplakin III) or nucleus (MUM-1, PGP 9.5 and thyroid transcription factor 1). We also evaluated three infectious agents (Aspergillus, calicivirus and West Nile virus). The staining with ENVISION+ or ImmPRESS was performed simultaneously for each antigen. The intensity of the reaction and background staining were scored. ImmPRESS yielded similar or higher reaction intensity than ENVISION+trade mark in 16/18 antigens. ImmPRESS produced abundant background with the other two antigens (calretinin and COX-2), which hindered interpretation of the specific reaction. The cost of ImmPRESS was 25% lower than for ENVISION+trade mark. Based on these results, ImmPRESS is a good polymer-based detection system for routine immunohistochemistry.
Assuntos
Anticorpos Monoclonais/imunologia , Antígenos/imunologia , Biotina/imunologia , Imuno-Histoquímica/métodos , Polímeros/química , Kit de Reagentes para Diagnóstico , Animais , Reações Antígeno-Anticorpo , Aspergillus/imunologia , Biotina/química , Caliciviridae/imunologia , Gatos , Cães , Formaldeído , Camundongos , Inclusão em Parafina , Coelhos , Kit de Reagentes para Diagnóstico/economia , Sensibilidade e Especificidade , Coloração e Rotulagem , Fixação de Tecidos , Vírus do Nilo Ocidental/imunologiaRESUMO
Wyoming experienced heavy West Nile virus (WNV) activity for the first time in 2003 and the area hardest hit was Goshen County. Little was known about the epidemiology of WNV in this region. This study describes the symptomatology of WNV and the association between certain behaviors and infection in Goshen County. Study participants were recruited from attendees of a health-fair sponsored by a local hospital, held October 1-3, 2003. A blood sample for WNV testing was obtained from each participant, and participants completed a questionnaire seeking information about the presence of specified symptoms consistent with WNV infection and risk factors possibly associated with infection. The samples were tested for anti-WNV IgM and IgG at the Wyoming Public Health Laboratory. Eight-hundred sixty-nine residents of Goshen County participated, and 122 (14.0%) were seropositive for anti-WNV IgM or IgG. Sixty (59.4%) of 101 persons seropositive for anti-WNV IgM experienced at least one symptom in the previous 4 months consistent with WNV infection, compared with 323 (43.2%) of 747 seronegative persons, resulting in an attributable risk of WNV seropositivity of 16.2%. Of the many symptoms queried, muscle aches (OR 2.63, 95% CI 1.69-4.09), skin rash (OR 6.35, 95% CI 3.74-10.80), fever (OR 2.56, 95% Cl 1.50-4.36), and muscle weakness (OR 2.33, 95% CI 1.34-4.02) were significantly associated with seropositivity on univariate analysis. By multivariate analysis, only skin rash remained significant. Risk factor analysis showed those spending > or =3 hours outside per day were more likely to be seropositive than those spending less time outside per day ( p < 0.05). This study corroborates the belief that a minority of persons infected with WNV develop symptoms attributable to WNV, and also demonstrates that some symptoms are more significantly associated with infection than others.
Assuntos
Anticorpos Antivirais/sangue , Febre do Nilo Ocidental/epidemiologia , Vírus do Nilo Ocidental/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Intervalos de Confiança , Exantema/epidemiologia , Feminino , Inquéritos Epidemiológicos , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Masculino , Pessoa de Meia-Idade , Debilidade Muscular/epidemiologia , Razão de Chances , Fatores de Risco , Estudos Soroepidemiológicos , Febre do Nilo Ocidental/diagnóstico , Vírus do Nilo Ocidental/isolamento & purificação , Wyoming/epidemiologiaRESUMO
OBJECTIVE: To determine the onset of immunity after IM administration of a single dose of a recombinant canarypox virus vaccine against West Nile virus (WNV) in horses in a blind challenge trial. ANIMALS: 20 mixed-breed horses. PROCEDURE: Horses with no prior exposure to WNV were randomly assigned to 1 of 2 groups (10 horses/group). In 1 group, a recombinant canarypox virus vaccine against WNV was administered to each horse once (day 0). The other 10 control horses were untreated. On day 26, 9 treated and 10 control horses were challenged via the bites of mosquitoes (Aedes albopictus) infected with WNV. Clinical responses and WNV isolation were monitored for 14 days after challenge exposure; antibody responses against WNV after administration of the vaccine and challenge were also assessed in both groups. RESULTS: Following challenge via WNV-infected mosquitoes, 1 of 9 treated horses developed viremia. In contrast, 8 of 10 control horses developed viremia after challenge exposure to WNV-infected mosquitoes. All horses seroconverted after WNV challenge; compared with control horses, antibody responses in the horses that received the vaccine were detected earlier. CONCLUSIONS AND CLINICAL RELEVANCE: In horses, a single dose of the recombinant canarypox virus-WNV vaccine appears to provide early protection against development of viremia after challenge with WNV-infected mosquitoes, even in the absence of measurable antibody titers in some horses. This vaccine may provide veterinarians with an important tool in controlling WNV infection during a natural outbreak or under conditions in which a rapid onset of protection is required.
Assuntos
Doenças dos Cavalos/imunologia , Doenças dos Cavalos/prevenção & controle , Doenças dos Cavalos/virologia , Vacinas Virais/imunologia , Febre do Nilo Ocidental/veterinária , Vírus do Nilo Ocidental/imunologia , Aedes/virologia , Análise de Variância , Animais , Anticorpos Antivirais/imunologia , Vírus da Varíola dos Canários/imunologia , CavalosAssuntos
Surtos de Doenças/prevenção & controle , Ensaio de Imunoadsorção Enzimática , Febre do Nilo Ocidental/diagnóstico , Vírus do Nilo Ocidental/isolamento & purificação , Animais , Aves/virologia , Centers for Disease Control and Prevention, U.S. , Culicidae/virologia , Indústria Farmacêutica , Saúde Global , Humanos , Insetos Vetores , Vigilância da População , Estados Unidos/epidemiologia , United States Food and Drug Administration , Febre do Nilo Ocidental/epidemiologia , Febre do Nilo Ocidental/virologia , Vírus do Nilo Ocidental/imunologiaAssuntos
Surtos de Doenças/veterinária , Doenças dos Cavalos/economia , Febre do Nilo Ocidental/veterinária , Animais , Colorado/epidemiologia , Surtos de Doenças/economia , Doenças dos Cavalos/epidemiologia , Doenças dos Cavalos/mortalidade , Doenças dos Cavalos/prevenção & controle , Cavalos , Nebraska/epidemiologia , Vacinas Virais/economia , Febre do Nilo Ocidental/economia , Febre do Nilo Ocidental/epidemiologia , Febre do Nilo Ocidental/prevenção & controle , Vírus do Nilo Ocidental/imunologiaRESUMO
Defined T cell epitopes for West Nile (WN) virus may be useful for developing subunit vaccines against WN virus infection and diagnostic reagents to detect WN virus-specific immune response. We applied a bioinformatics (EpiMatrix) approach to search the WN virus NY99 genome for HLA B*07 restricted cytotoxic T cell (CTL) epitopes. Ninety-five of 3,433 WN virus peptides scored above a predetermined cutoff, suggesting that these would be likely to bind to HLA B*07 and would also be likely candidate CTL epitopes. Compared with other methods for genome mapping, derivation of these ligands was rapid and inexpensive. Major histocompatibility complex ligands identified by this method may be used to screen T cells from WN virus-exposed persons for cell-mediated response to WN virus or to develop diagnostic reagents for immunopathogenesis studies and epidemiologic surveillance.