RESUMEN
West Nile virus (WNV) infection in humans can cause neurological deficits, including flaccid paralysis, encephalitis, meningitis, and mental status change. To better understand the neuropathogenesis of WNV in the peripheral and the central nervous systems (PNS and CNS), we used a mouse footpad inoculation model to simulate a natural peripheral infection. Localization of WNV in the nervous system using this model has suggested two routes of viral invasion of the CNS: axonal retrograde transport (ART) from the PNS and hematogenous diffusion via a breakdown in the blood-choroid-plexus barrier. C57BL/6J mice were treated with nocodazole, a microtubule inhibitor that blocks ART, prior to infection with WNV. Nocodazole-treated WNV-infected mice developed a viremia 1.5 log(10) greater than untreated WNV-infected control mice at days 3 to 4 post infection (PI). Although viremia was greater in nocodazole-treated mice, detection of virus in brain tissue (spinal cord, cortex, brainstem, and cerebellum), as measured by real-time reverse transcriptase-polymerase chain reaction (RT-PCR), did not occur until day 7. At these later time points (7 and 9 days PI), nocodazole-treated WNV-infected animals attained viral titers in these tissues similar to titers in the untreated WNV-infected control animals. These results demonstrate that a single dose of nocodazole delays, but does not block, WNV infection of the brain.
Asunto(s)
Encéfalo/virología , Nocodazol/farmacología , Moduladores de Tubulina/farmacología , Internalización del Virus/efectos de los fármacos , Fiebre del Nilo Occidental/virología , Virus del Nilo Occidental/fisiología , Animales , Encéfalo/patología , Ratones , Ratones Endogámicos C57BL , Reacción en Cadena de la Polimerasa , ARN Viral/genética , Factores de Tiempo , Carga Viral , Fiebre del Nilo Occidental/patología , Virus del Nilo Occidental/genética , Virus del Nilo Occidental/aislamiento & purificaciónRESUMEN
A review of the evidence for the efficacy of a commercially available computer-aided detection (CAD) system is presented. Retrospective studies point to a potential capability of detecting approximately 20% of cancers at least 1 year earlier than normally detected by single reading of mammograms. Several prospective studies have now been published showing an actual increase of detection from 1.7% to 18%. Suggestions are given for closing the gap between the potential and actual performance with CAD, including: improving the specificity of the CAD algorithm; improving the training of end users; presenting more or better information to the radiologist; and the possible need for decision support tools.
Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Mamografía/métodos , Interpretación de Imagen Radiográfica Asistida por Computador/normas , Algoritmos , Educación Médica Continua , Femenino , Humanos , Tamizaje Masivo/métodos , Radiología/educaciónRESUMEN
In light of the continuous spread of human pathogenic flaviviruses, in particular the mosquito-transmitted species, vaccine development remains a high priority on the public health agenda. On 26-27 April 2004, a conference was held in Bangkok, Thailand, to review current status of flavivirus vaccine development and related issues, focussing on dengue (DEN) and Japanese encephalitis (JE). This event, co-sponsored by the World Health Organization (WHO) and the Thai Ministry of Public Health, reviewed the progress made with vaccine development, sero-epidemiological studies and other accompanying activities critical for vaccine development and vaccination. The considerable interest in and awareness of the flavivirus diseases and their prevention by public health decision makers, as well as the establishment of two dedicated programmes for dengue and Japanese encephalitis vaccine development raise hopes that new or improved vaccines will become available in the coming years.
Asunto(s)
Flavivirus/inmunología , Vacunas Virales/inmunología , Anticuerpos Antivirales/sangre , Ensayos Clínicos como Asunto , Virus del Dengue/inmunología , Humanos , Vacunas contra la Encefalitis Japonesa/inmunología , Virus del Nilo Occidental/inmunología , Vacuna contra la Fiebre Amarilla/inmunologíaAsunto(s)
Arbovirus/clasificación , Terminología como Asunto , Virus/clasificación , Animales , Humanos , PlantasRESUMEN
In late summer 1999, the first domestically acquired human cases of WN encephalitis were documented in the USA. Aggressive vector-control and public education efforts by state and local public health officials limited the extent of human involvement. The discovery of virus-infected, overwintering mosquitoes during the winter of 1999-2000, predicted renewed virus activity for the following spring, and prompted early season vector-control activities and disease surveillance efforts in NYC and the surrounding areas. These surveillance efforts were focused on identifying WN virus infections in birds and mosquitoes as predictors of the potential risk of transmission to humans. By the end of the 2000 mosquito-borne disease transmission season, WN virus activity had been documented as far north as the states of Vermont and New Hampshire, and as far south as the state of North Carolina. The ongoing impacts that WN virus will have on wildlife, domestic animal and human populations of the western hemisphere are not yet known. Plans are in place for public health officials and scientists to monitor the further expansion of WN virus with the establishment or enhancement of vector-borne disease surveillance and control programs throughout the eastern seaboard. The valuable lessons learned from the detection and response to the introduction of WN virus into NYC should prove useful if and when subsequent intrusions of new disease agents occur.
Asunto(s)
Fiebre del Nilo Occidental/epidemiología , Virus del Nilo Occidental/aislamiento & purificación , Animales , Brotes de Enfermedades , Ecosistema , Flavivirus/aislamiento & purificación , Humanos , Insectos Vectores , Ciudad de Nueva York/epidemiología , América del Norte/epidemiología , Vigilancia de la Población , Fiebre del Nilo Occidental/etiología , Virus del Nilo Occidental/genéticaAsunto(s)
Enfermedades Transmisibles Emergentes/epidemiología , Brotes de Enfermedades , Fiebre del Nilo Occidental/epidemiología , Virus del Nilo Occidental , Animales , Enfermedades Transmisibles Emergentes/mortalidad , Enfermedades Transmisibles Emergentes/virología , Culex/virología , Salud Global , Humanos , Insectos Vectores/virología , Ciudad de Nueva York/epidemiología , Estados Unidos/epidemiología , Fiebre del Nilo Occidental/mortalidad , Fiebre del Nilo Occidental/virología , Virus del Nilo Occidental/clasificación , Virus del Nilo Occidental/genética , Virus del Nilo Occidental/aislamiento & purificación , Virus del Nilo Occidental/metabolismoRESUMEN
In 1999, the U.S. West Nile (WN) virus epidemic was preceded by widespread reports of avian deaths. In 2000, ArboNET, a cooperative WN virus surveillance system, was implemented to monitor the sentinel epizootic that precedes human infection. This report summarizes 2000 surveillance data, documents widespread virus activity in 2000, and demonstrates the utility of monitoring virus activity in animals to identify human risk for infection.
Asunto(s)
Brotes de Enfermedades , Fiebre del Nilo Occidental/epidemiología , Virus del Nilo Occidental , Animales , Enfermedades de las Aves/epidemiología , Enfermedades de las Aves/virología , Culicidae/virología , Ecología , Enfermedades de los Caballos/epidemiología , Enfermedades de los Caballos/virología , Caballos , Humanos , Vigilancia de la Población , Pájaros Cantores/virología , Estados Unidos/epidemiología , Fiebre del Nilo Occidental/veterinaria , Fiebre del Nilo Occidental/virologíaRESUMEN
Surveillance of mosquito populations for virus activity is not often performed by small, vector-control districts because they do not have the financial resources to use virus isolation, or newer methods such as the polymerase chain reaction. Consequently, development and refinements of rapid, sensitive, and simple enzyme-linked immunosorbent assays (ELISAs) applicable to a wide variety of public health settings are justified. We have developed an antigen-capture ELISA for the detection of eastern equine encephalitis (EEE) virus in mosquitoes that uses both monoclonal capture and detector antibodies. The sensitivity of this assay is 4.0-5.0 log10 plaque-forming units/ml, which is comparable to previously published EEE antigen-capture assays developed with polyclonal antibody reagents. This test identifies only North American strains of EEE virus and does not react with either western equine encephalitis or Highlands J viruses. Test sensitivity was enhanced by sonicating mosquito pools, treating them with Triton X-100, and increasing the time and temperature of antigen incubation. The conversion of this ELISA to a monoclonal antibody-based format should result in a readily standardizable and transferable assay that will permit laboratories lacking virus isolation facilities to conduct EEE virus surveillance.
Asunto(s)
Aedes/virología , Virus de la Encefalitis Equina del Este/aislamiento & purificación , Encefalomielitis Equina Oriental/diagnóstico , Ensayo de Inmunoadsorción Enzimática/métodos , Animales , Anticuerpos Monoclonales/inmunología , Especificidad de Anticuerpos , Antígenos Virales/análisis , Antígenos Virales/inmunología , Chlorocebus aethiops , Virus de la Encefalitis Equina del Este/crecimiento & desarrollo , Femenino , Glicoproteínas/inmunología , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Células Vero , Proteínas Virales/inmunologíaAsunto(s)
Fiebre del Nilo Occidental , Animales , Anticuerpos Antivirales/análisis , Aves/virología , Culicidae/virología , ADN Viral/análisis , Humanos , Insectos Vectores , Estados Unidos/epidemiología , Fiebre del Nilo Occidental/diagnóstico , Fiebre del Nilo Occidental/epidemiología , Fiebre del Nilo Occidental/prevención & control , Fiebre del Nilo Occidental/terapia , Virus del Nilo Occidental/aislamiento & purificaciónRESUMEN
The specific mechanisms by which antibodies neutralize flavivirus infectivity are not completely understood. To study these mechanisms in more detail, we analyzed the ability of a well-defined set of anti-dengue (DEN) virus E-glycoprotein-specific monoclonal antibodies (MAbs) to block virus adsorption to Vero cells. In contrast to previous studies, the binding sites of these MAbs were localized to one of three structural domains (I, II, and III) in the E glycoprotein. The results indicate that most MAbs that neutralize virus infectivity do so, at least in part, by the blocking of virus adsorption. However, MAbs specific for domain III were the strongest blockers of virus adsorption. These results extend our understanding of the structure-function relationships in the E glycoprotein of DEN virus and provide the first direct evidence that domain III encodes the primary flavivirus receptor-binding motif.
Asunto(s)
Virus del Dengue/fisiología , Proteínas del Envoltorio Viral/inmunología , Animales , Anticuerpos Monoclonales/inmunología , Anticuerpos Monoclonales/farmacología , Anticuerpos Antivirales/inmunología , Anticuerpos Antivirales/farmacología , Chlorocebus aethiops , Células Vero , Replicación Viral/efectos de los fármacos , Replicación Viral/inmunologíaRESUMEN
Introduction of West Nile (WN) virus into the United States in 1999 created major human and animal health concerns. Currently, no human or veterinary vaccine is available to prevent WN viral infection, and mosquito control is the only practical strategy to combat the spread of disease. Starting with a previously designed eukaryotic expression vector, we constructed a recombinant plasmid (pCBWN) that expressed the WN virus prM and E proteins. A single intramuscular injection of pCBWN DNA induced protective immunity, preventing WN virus infection in mice and horses. Recombinant plasmid-transformed COS-1 cells expressed and secreted high levels of WN virus prM and E proteins into the culture medium. The medium was treated with polyethylene glycol to concentrate proteins. The resultant, containing high-titered recombinant WN virus antigen, proved to be an excellent alternative to the more traditional suckling-mouse brain WN virus antigen used in the immunoglobulin M (IgM) antibody-capture and indirect IgG enzyme-linked immunosorbent assays. This recombinant antigen has great potential to become the antigen of choice and will facilitate the standardization of reagents and implementation of WN virus surveillance in the United States and elsewhere.
Asunto(s)
Antígenos Virales/inmunología , Vacunas de ADN/inmunología , Proteínas del Envoltorio Viral/inmunología , Vacunas Virales/inmunología , Fiebre del Nilo Occidental/diagnóstico , Secuencia de Aminoácidos , Animales , Antígenos Virales/biosíntesis , Antígenos Virales/genética , Células COS , Chlorocebus aethiops , Ensayo de Inmunoadsorción Enzimática/métodos , Femenino , Expresión Génica , Caballos , Ratones , Ratones Endogámicos ICR , Datos de Secuencia Molecular , Plásmidos , Vacunas de ADN/genética , Proteínas del Envoltorio Viral/biosíntesis , Proteínas del Envoltorio Viral/genética , Vacunas Virales/genética , Fiebre del Nilo Occidental/inmunología , Fiebre del Nilo Occidental/prevención & control , Fiebre del Nilo Occidental/virología , Virus del Nilo Occidental/genética , Virus del Nilo Occidental/inmunologíaAsunto(s)
Antígenos Virales/sangre , Fiebre del Nilo Occidental/diagnóstico , Virus del Nilo Occidental/inmunología , Ensayo de Inmunoadsorción Enzimática , Humanos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Estados Unidos/epidemiología , Fiebre del Nilo Occidental/epidemiología , Virus del Nilo Occidental/genética , Virus del Nilo Occidental/aislamiento & purificaciónRESUMEN
The outbreak of West Nile (WN) encephalitis in the United States has rekindled interest in developing direct methods for prevention and control of human flaviviral infections. Although equine WN vaccines are currently being developed, a WN vaccine for humans is years away. There is also no specific therapeutic agent for flaviviral infections. The incidence of human WN virus infection is very low, which makes it difficult to target the human populations in need of vaccination and to assess the vaccine's economic feasibility. It has been shown, however, that prophylactic application of antiflaviviral antibody can protect mice from subsequent virus challenge. This model of antibody prophylaxis using murine monoclonal antibodies (MAbs) has been used to determine the timing of antibody application and specificity of applied antibody necessary for successful prophylaxis. The major flaviviral antigen is the envelope (E) glycoprotein that binds cellular receptors, mediates cell membrane fusion, and contains an array of epitopes that elicit virus-neutralizing and nonneutralizing antibodies. The protective efficacy of an E-glycoprotein-specific MAb is directly related to its ability to neutralize virus infectivity. The window for successful application of prophylactic antibody to prevent flaviviral encephalitis closes at about 4 to 6 days postinfection concomitant with viral invasion of the brain. Using murine MAbs to modify human disease results in a human antimouse antibody (HAMA) response that eventually limits the effectiveness of subsequent murine antibody applications. To reduce the HAMA response and make these MAbs more generally useful for humans, murine MAbs can be "humanized" or human MAbs with analogous reactivities can be developed. Antiflaviviral human or humanized MAbs might be practical and cost-effective reagents for preventing or modifying flaviviral diseases.
Asunto(s)
Anticuerpos Antivirales/uso terapéutico , Encefalitis por Arbovirus/prevención & control , Infecciones por Flavivirus/prevención & control , Flavivirus/inmunología , Animales , Anticuerpos Monoclonales/uso terapéutico , Modelos Animales de Enfermedad , Humanos , Ratones , Fiebre del Nilo Occidental/prevención & controlRESUMEN
The authors report on the development and application of a rapid TaqMan assay for the detection of West Nile (WN) virus in a variety of human clinical specimens and field-collected specimens. Oligonucleotide primers and FAM- and TAMRA-labeled WN virus-specific probes were designed by using the nucleotide sequence of the New York 1999 WN virus isolate. The TaqMan assay was compared to a traditional reverse transcriptase (RT)-PCR assay and to virus isolation in Vero cells with a large number ( approximately 500) of specimens obtained from humans (serum, cerebrospinal fluid, and brain tissue), field-collected mosquitoes, and avian tissue samples. The TaqMan assay was specific for WN virus and demonstrated a greater sensitivity than the traditional RT-PCR method and correctly identified WN virus in 100% of the culture-positive mosquito pools and 98% of the culture-positive avian tissue samples. The assay should be of utility in the diagnostic laboratory to complement existing human diagnostic testing and as a tool to conduct WN virus surveillance in the United States.
Asunto(s)
Enfermedades de las Aves/diagnóstico , Culicidae/virología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Polimerasa Taq/metabolismo , Fiebre del Nilo Occidental/diagnóstico , Virus del Nilo Occidental/aislamiento & purificación , Animales , Enfermedades de las Aves/virología , Aves/virología , Encéfalo/virología , Chlorocebus aethiops , Humanos , ARN Viral/sangre , ARN Viral/líquido cefalorraquídeo , Sensibilidad y Especificidad , Células Vero , Cultivo de Virus , Fiebre del Nilo Occidental/veterinaria , Fiebre del Nilo Occidental/virología , Virus del Nilo Occidental/genéticaRESUMEN
An outbreak of encephalitis occurred in New York City in late August 1999, the first caused by West Nile virus in North America. Histopathologic and immunopathologic examinations performed on human autopsy materials helped guide subsequent laboratory and epidemiologic investigations that led to identification of the etiologic agent.
Asunto(s)
Encéfalo/patología , Brotes de Enfermedades , Médula Espinal/patología , Fiebre del Nilo Occidental/patología , Fiebre del Nilo Occidental/virología , Virus del Nilo Occidental/aislamiento & purificación , Antígenos Virales/análisis , Autopsia , Encéfalo/virología , Humanos , Inmunohistoquímica , Neuronas/patología , Neuronas/virología , Ciudad de Nueva York/epidemiología , Médula Espinal/virología , Fiebre del Nilo Occidental/epidemiología , Virus del Nilo Occidental/inmunologíaRESUMEN
A paramyxovirus virus termed Nipah virus has been identified as the etiologic agent of an outbreak of severe encephalitis in people with close contact exposure to pigs in Malaysia and Singapore. The outbreak was first noted in late September 1998 and by mid-June 1999, more than 265 encephalitis cases, including 105 deaths, had been reported in Malaysia, and 11 cases of encephalitis or respiratory illness with one death had been reported in Singapore. Electron microscopic, serologic, and genetic studies indicate that this virus belongs to the family Paramyxoviridae and is most closely related to the recently discovered Hendra virus. We suggest that these two viruses are representative of a new genus within the family Paramyxoviridae. Like Hendra virus, Nipah virus is unusual among the paramyxoviruses in its ability to infect and cause potentially fatal disease in a number of host species, including humans.
Asunto(s)
Encefalitis Viral/virología , Infecciones por Paramyxoviridae/epidemiología , Infecciones por Paramyxoviridae/virología , Paramyxovirinae , Animales , Anticuerpos Antivirales/sangre , Brotes de Enfermedades , Encefalitis Viral/epidemiología , Endotelio Vascular/patología , Endotelio Vascular/virología , Genes Virales , Células Gigantes/patología , Células Gigantes/virología , Humanos , Malasia/epidemiología , Microscopía Electrónica , Datos de Secuencia Molecular , Nucleocápside/ultraestructura , Infecciones por Paramyxoviridae/transmisión , Infecciones por Paramyxoviridae/veterinaria , Paramyxovirinae/clasificación , Paramyxovirinae/genética , Paramyxovirinae/aislamiento & purificación , Paramyxovirinae/ultraestructura , Filogenia , Sistema Respiratorio/virología , Infecciones del Sistema Respiratorio/epidemiología , Infecciones del Sistema Respiratorio/veterinaria , Infecciones del Sistema Respiratorio/virología , Análisis de Secuencia de ADN , Singapur/epidemiología , Porcinos , Enfermedades de los Porcinos/epidemiología , Enfermedades de los Porcinos/virología , Vasculitis/virología , Proteínas Virales/genéticaRESUMEN
Immunoglobulin M antibody-capture enzyme-linked immunosorbent assay (MAC-ELISA) is a rapid and versatile diagnostic method that readily permits the combination of multiple assays. Test consolidation is especially important for arthropod-borne viruses (arboviruses) which belong to at least three virus families: the Togaviridae, Flaviviridae, and Bunyaviridae. Using prototype viruses from each of these families and a panel of well-characterized human sera, we have evaluated and standardized a combined MAC-ELISA capable of identifying virus infections caused by members of each virus family. Furthermore, by grouping antigens geographically and utilizing known serological cross-reactivities, we have reduced the number of antigens necessary for testing, while maintaining adequate detection sensitivity. We have determined that a 1:400 serum dilution is most appropriate for screening antiviral antibody, using a positive-to-negative ratio of >/=2.0 as a positive cutoff value. With a blind-coded human serum panel, this combined MAC-ELISA was shown to have test sensitivity and specificity that correlated well with those of other serological techniques.
Asunto(s)
Anticuerpos Antivirales/sangre , Infecciones por Arbovirus/diagnóstico , Ensayo de Inmunoadsorción Enzimática/normas , Inmunoglobulina M/sangre , Antígenos Virales/inmunología , Infecciones por Arbovirus/sangre , Infecciones por Arbovirus/inmunología , Infecciones por Bunyaviridae/diagnóstico , Centers for Disease Control and Prevention, U.S. , Reacciones Cruzadas , Infecciones por Flaviviridae/diagnóstico , Geografía , Humanos , Control de Calidad , Reproducibilidad de los Resultados , Infecciones por Togaviridae/diagnóstico , Estados UnidosRESUMEN
Monoclonal antibody (MAb)-based capture enzyme-linked immunosorbent assays (ELISAs) for the detection of anti-arboviral immunoglobulin G (IgG ELISAs) were developed for a comprehensive array of medically important arboviruses from the Alphavirus, Flavivirus, and Bunyavirus genera. Tests were optimized and standardized so that maximum homology could be maintained among working parameters for the different viral agents, enabling a wide range of viruses to be easily tested for at one time. MAbs were screened for suitability as capture vehicles for antigens from the three genera. The final test configuration utilized group-reactive MAbs eastern equine encephalitis virus 1A4B-6, dengue 2 virus 4G2, and La Crosse encephalitis virus 10G5.4 to capture the specific inactivated viral antigens. Serum IgG was detected by using alkaline phosphatase-conjugated anti-human IgG (Fc portion). A dilution of 1:400 was chosen as the universal screening serum dilution, with endpoint titrations of serum samples testing positive eliminating occasional false-positive results. IgG ELISA results correlated with those of the standard plaque-reduction neutralization assays. As expected, some test cross-reactivity was encountered within the individual genera, and tests were interpreted within the context of these reactions. The tests were standardized for laboratory diagnosis of arboviral infections, with the intent that they be used in tandem with the corresponding IgM antibody-capture ELISAs.
Asunto(s)
Anticuerpos Monoclonales , Anticuerpos Antivirales/sangre , Infecciones por Arbovirus/diagnóstico , Ensayo de Inmunoadsorción Enzimática/métodos , Inmunoglobulina G/sangre , Infecciones por Alphavirus/diagnóstico , Antígenos Virales/inmunología , Infecciones por Arbovirus/sangre , Infecciones por Arbovirus/inmunología , Infecciones por Bunyaviridae/diagnóstico , Centers for Disease Control and Prevention, U.S. , Reacciones Cruzadas , Dengue/diagnóstico , Diagnóstico Diferencial , Encefalitis de California/diagnóstico , Encefalomielitis Equina/diagnóstico , Infecciones por Flavivirus/diagnóstico , Humanos , Virus La Crosse , Reproducibilidad de los Resultados , Estados Unidos , Ensayo de Placa ViralRESUMEN
The epidemic/epizootic of West Nile (WN) encephalitis in the northeastern United States in the summer and fall of 1999 was an unprecedented event, underscoring the ease with which emerging infectious pathogens can be introduced into new geographic areas in today's era of rapid transportation and increased movement of people, animals, and commodities. This epidemic/epizootic and the increased frequency of other exotic pathogens being imported into the United States raises the issue of whether local, state, and national public health agencies are prepared to deal with epidemics/epizootics of vector-borne infectious diseases. The overwintering of WN virus and the epizootic transmission in the summer of 2000 reinforces the need to rebuild the public health infrastructure to deal with vector-borne diseases in this country. This article summarizes guidelines for surveillance, prevention, and control of WN virus that were drafted in December 1999 to help prepare state and local health departments for monitoring WN virus activity in the spring and summer of 2000 and also summarizes the data collected from those surveillance systems through September 2000.
Asunto(s)
Guías como Asunto , Fiebre del Nilo Occidental/epidemiología , Fiebre del Nilo Occidental/prevención & control , Animales , Centers for Disease Control and Prevention, U.S. , Culicidae/virología , Reservorios de Enfermedades , Humanos , Insectos Vectores , Vigilancia de la Población , Práctica de Salud Pública , Investigación , Estados Unidos/epidemiología , Fiebre del Nilo Occidental/diagnóstico , Fiebre del Nilo Occidental/veterinaria , Virus del Nilo Occidental/aislamiento & purificaciónRESUMEN
We have generated a single-chain variable fragment (ScFv) antibody, from a previously well-characterized monoclonal antibody (MAb) to Venezuelan equine encephalitis (VEE) virus, 5B4D-6. The variable regions of the heavy (V(H)) and light (V(L)) chain antibody genes, were connected by a DNA linker and cloned in the phagemid vector pCANTAB5E. The ScFv clone in Escherichia coli strain TG-1, 5B4D-6-6, was expressed as a approximately 30 kDa ScFv protein and higher molecular weight fusion products which were functional in recognizing VEE virus by enzyme-linked immunosorbent assay (ELISA). Results were reproduced in Escherichia coli strain HB2151, where clone D66 was expressed mainly as soluble periplasmic protein. The D66 ScFv antibody bound VEE virus strongly as determined by ELISA. Nucleotide sequence analysis of 5B4D-6-6 ScFv indicated that the Vkappa gene belonged to family XVI, subgroup V, while the V(H) gene was unique in its sequence, though its amino acid sequence could be subgrouped as IA. The deduced protein sequence of D66 was highly homologous to published murine ScFv protein sequences. This work demonstrates, for the first time, cloning of a functional ScFv antibody against VEE virus.