Asunto(s)
Arbovirus/clasificación , Terminología como Asunto , Virus/clasificación , Animales , Humanos , PlantasRESUMEN
Following a 19-year hiatus, Venezuelan equine encephalitis (VEE) reemerged in western Venezuela in December 1992. This outbreak is important in understanding VEE emergence because phylogenetic studies imply that sympatric, enzootic, subtype ID VEE viruses mutated to generate the epizootic/epidemic. Although the 1992-1993 strains belong to subtype IC, a serotype implicated in extensive outbreaks during the 1960s and in 1995, relatively small numbers of human and equine cases occurred in 1992-1993. We, therefore, evaluated the pathogenicity of these Venezuelan enzootic ID and epizootic IC viruses to determine 1) if they exhibit phenotypes like those described previously for more distantly related enzootic and epizootic strains, and 2) if the 1992-1993 outbreak was limited by the inability of these IC viruses to exploit equines as amplification hosts. All strains were virulent in mice and guinea pigs, but were benign for cotton rats, natural hosts of enzootic viruses. However, only the IC strains produced equine disease, with mean peak viremias of 10(5) suckling mouse 50% lethal doses per mL serum, and some titers exceeding 10(7). These viremias approximate those observed previously with VEE strains isolated during more extensive epizootics, suggesting that efficient equine amplification did not limit the scope and duration of the 1992-1993 outbreak. Enzootic ID virus infection protected all horses from challenge with epizootic strain P676, supporting the hypothesis that epizootics bypass regions of enzootic transmission due to natural immunization of equines by enzootic VEE viruses.
Asunto(s)
Brotes de Enfermedades/veterinaria , Virus de la Encefalitis Equina Venezolana/patogenicidad , Encefalomielitis Equina Venezolana/epidemiología , Encefalomielitis Equina Venezolana/virología , Enfermedades de los Caballos/virología , Viremia/virología , Animales , Anopheles , Chlorocebus aethiops , Cricetinae , Virus de la Encefalitis Equina Venezolana/clasificación , Encefalomielitis Equina Venezolana/sangre , Femenino , Cobayas , Enfermedades de los Caballos/sangre , Enfermedades de los Caballos/epidemiología , Caballos , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C3H , Ratones Endogámicos C57BL , Distribución Aleatoria , Ratas , Enfermedades de los Roedores/virología , Sigmodontinae , Venezuela/epidemiología , Células Vero , VirulenciaRESUMEN
The identification of variants that are unable to bind membrane receptor preparations (MRPs) has previously been shown to select attenuated yellow fever and Japanese encephalitis viruses. In this study, this methodology has been extended to the tick-borne serocomplex of flaviviruses. Langat (LGT) virus strain TP21 was bound to mouse or human brain MRPs and viruses that escaped binding were isolated and characterized. In addition, variant viruses escaping neutralization by the monoclonal antibody (MAb) 9F9 were also isolated. All of the variant viruses were attenuated for mouse neurovirulence (> or =13-fold). Sequence analysis of the prM/E region of the variant viruses identified mutations within the stem-anchor region of the E protein in variants isolated following incubation with mouse or human brain MRPs at a pH > or = 7.0. The MAb 9F9 variants and MRP variants isolated at pH 5.0, which should induce a conformational shift in the viral E protein, had nearly identical mutations in the prM/M protein immediately N-terminal to the prM/E cleavage site. MAb 9F9 neutralized none of the variant viruses and hemagglutination inhibition assays suggest that the variant virus surface proteins have slightly different conformations compared to the parental virus. These data support previous work indicating that the stem-anchor region of the E protein is important to the surface architecture of the tick-borne flaviviruses. In addition, this study demonstrates that the M protein is at least partially solvent accessible on the virion surface and that the M protein plays a role in maintaining the conformation of the M/E surface complex.
Asunto(s)
Virus de la Encefalitis Transmitidos por Garrapatas/patogenicidad , Encefalitis Transmitida por Garrapatas/virología , Sistema Nervioso/virología , Proteínas del Envoltorio Viral/genética , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Animales , Virus de la Encefalitis Transmitidos por Garrapatas/genética , Humanos , Ratones , Datos de Secuencia Molecular , Virulencia/genética , Replicación Viral/genéticaRESUMEN
Jatobal (JAT) virus was isolated in 1985 from a carnivore (Nasua nasua) in Tucuruí, Pará state, Brazil and was classified as a distinct member of the Simbu serogroup of the Bunyavirus genus, family Bunyaviridae on the basis of neutralization tests. On the basis of nucleotide sequencing, we have found that the small (S) RNA of JAT virus is very similar (>95% identity) to that of Oropouche (ORO) virus, in particular, the Peruvian genotype of ORO virus. In comparison, limited nucleotide sequencing of the G2 protein gene, encoded by the middle (M) RNA, of JAT and ORO viruses, revealed relatively little identity (<66%) between these two viruses. Neutralization tests confirmed the lack of cross-reactivity between the viruses. These results suggest that JAT virus is a reassortant containing the S RNA of ORO virus. JAT virus was attenuated in hamsters compared to ORO virus suggesting that the S RNA of ORO virus is not directly involved in hamster virulence.
Asunto(s)
Infecciones por Bunyaviridae/virología , ARN Viral/genética , Virus Reordenados/genética , Virus Simbu/genética , Virus Simbu/patogenicidad , Secuencia de Aminoácidos , Animales , Infecciones por Bunyaviridae/fisiopatología , Cricetinae , Femenino , Mesocricetus , Datos de Secuencia Molecular , Pruebas de Neutralización , Nucleocápside/genética , Nucleocápside/metabolismo , Proteínas no Estructurales Virales/química , Proteínas no Estructurales Virales/genética , Proteínas no Estructurales Virales/metabolismo , VirulenciaRESUMEN
This report describes Trocara virus, a newly recognized member of the genus Alphavirus, that has been isolated from Aedes serratus mosquitoes collected at two widely separated sites in the Amazon Basin. Biological, antigenic and genetic characteristics of the new virus are given. Results of these studies indicate that Trocara virus is the first member of a newly discovered antigenic complex within the family Togaviridae genus Alphavirus. The public health and veterinary importance of Trocara virus is still unknown.
Asunto(s)
Aedes/virología , Alphavirus/genética , Alphavirus/aislamiento & purificación , Alphavirus/ultraestructura , Animales , Brasil , Pruebas de Fijación del Complemento , Cricetinae , Cartilla de ADN , Pruebas de Hemaglutinación , Ratones , Microscopía Electrónica , Perú , Reacción en Cadena de la Polimerasa , ARN Viral/aislamiento & purificación , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Oropouche (ORO) virus is an emerging infectious agent that has caused numerous outbreaks of an acute febrile (dengue-like) illness among humans in Brazil, Peru, and Panama. Diagnosis of ORO virus infection is based mainly on serology. Two different antigens, hamster serum antigen (HSA) and Vero cell lysate antigen (VCLA), are currently used in enzyme immunoassays (EIAs) in Brazil and Peru, respectively, to investigate the epidemiology of ORO virus infection. Both antigens involve use of infectious virus, and for this reason their use is restricted. Consequently, the frequency and distribution of ORO virus infection are largely unexplored in other countries of South America. This report describes the use of a bacterially expressed recombinant nucleocapsid (rN) protein of ORO virus in EIAs for the diagnosis of ORO virus infection. The data revealed that the purified rN protein is comparable to the authentic viral N protein in its antigenic characteristics and is highly sensitive and specific in EIAs. Among 183 serum samples tested, a high degree of concordance was found between rN protein-based EIA and HSA- and VCLA-based EIAs for the detection of both ORO virus-specific immunoglobulin M (IgM) and IgG antibodies. The high sensitivity, specificity, and safety of the rN protein-based EIA make it a useful diagnostic technique that can be widely used to detect ORO virus infection in South America.
Asunto(s)
Anticuerpos Antivirales/sangre , Infecciones por Bunyaviridae/diagnóstico , Técnicas para Inmunoenzimas , Proteínas de la Nucleocápside/inmunología , Virus Simbu/inmunología , Animales , Antígenos Virales/inmunología , Infecciones por Bunyaviridae/virología , Chlorocebus aethiops , Cricetinae , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Mesocricetus , Proteínas de la Nucleocápside/genética , Proteínas Recombinantes/inmunología , Células VeroRESUMEN
The molecular determinants responsible for flavivirus host cell binding and tissue tropism are largely unknown, although domain III of the envelope protein has been implicated in these functions. We examined the solution properties and antagonist activity of Langat virus domain III. Our results suggest that domain III adopts a stably folded structure that can mediate binding of tick-borne flaviviruses but not mosquito-borne flaviviruses to their target cells. Three clusters of phylogenetically conserved residues are identified that may be responsible for the vector-specific antagonist activity of domain III.
Asunto(s)
Virus de la Encefalitis Transmitidos por Garrapatas/efectos de los fármacos , Receptores Virales/antagonistas & inhibidores , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/farmacología , Secuencia de Aminoácidos , Animales , Chlorocebus aethiops , Dicroismo Circular , Secuencia Conservada , Virus de la Encefalitis Transmitidos por Garrapatas/metabolismo , Flavivirus/efectos de los fármacos , Flavivirus/metabolismo , Modelos Moleculares , Datos de Secuencia Molecular , Fragmentos de Péptidos/química , Fragmentos de Péptidos/farmacología , Estructura Terciaria de Proteína , Receptores Virales/metabolismo , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/metabolismo , Alineación de Secuencia , Especificidad por Sustrato , Células Vero , Proteínas del Envoltorio Viral/metabolismoAsunto(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
A controlled, randomized, double-blind clinical trial evaluated whether two attenuated recombinant poxviruses with identical Japanese encephalitis virus (JEV) gene insertions, NYVAC-JEV and ALVAC-JEV, were safe and immunogenic in volunteers. Groups of 10 volunteers distinguished by vaccinia immune status received two doses of each vaccine. The vaccines appeared to be equally safe and well tolerated in volunteers, but more reactogenic than licensed formalin-inactivated JE and placebo vaccines given as controls. NYVAC-JEV and ALVAC-JEV vaccine recipients had frequent occurrence of local warmth, erythema, tenderness, and/or arm pain after vaccination. There was no apparent effect of vaccinia immune status on frequency or magnitude of local and systemic reactions. NYVAC-JEV elicited antibody responses to JEV antigens in recipients but ALVAC-JEV vaccine poorly induced antibody responses. However, NYVAC-JEV vaccine induced neutralizing antibody responses only in vaccinia-nonimmune recipients while vaccinia-immune volunteers failed to develop protective antibodies (5/5 vs. 0/5 seroconversion, p<0.01). These data suggest that preexisting immunity to poxvirus vector may suppress antibody responses to recombinant gene products.
Asunto(s)
Virus de la Encefalitis Japonesa (Especie)/genética , Virus de la Encefalitis Japonesa (Especie)/inmunología , Poxviridae/genética , Poxviridae/inmunología , Vaccinia/inmunología , Vacunas Virales/farmacología , Anticuerpos Antivirales/biosíntesis , Antígenos Virales/genética , Método Doble Ciego , Encefalitis Japonesa/inmunología , Encefalitis Japonesa/prevención & control , Eritema/etiología , Vectores Genéticos , Humanos , Pruebas de Neutralización , Seguridad , Vacunas Atenuadas/efectos adversos , Vacunas Atenuadas/inmunología , Vacunas Atenuadas/farmacología , Vacunas Sintéticas/efectos adversos , Vacunas Sintéticas/inmunología , Vacunas Sintéticas/farmacología , Vacunas Virales/efectos adversos , Vacunas Virales/inmunologíaRESUMEN
The nucleotide sequence of the S RNA segment of the Oropouche (ORO) virus prototype strain TRVL 9760 was determined and found to be 754 nucleotides in length. In the virion-complementary orientation, the RNA contained two overlapping open reading frames of 693 and 273 nucleotides that were predicted to encode proteins of 231 and 91 amino acids, respectively. Subsequently, the nucleotide sequences of the nucleocapsid genes of 27 additional ORO virus strains, representing a 42 year interval and a wide geographical range in South America, were determined. Phylogenetic analyses revealed that all the ORO virus strains formed a monophyletic group that comprised three distinct lineages. Lineage I contained the prototype strain from Trinidad and most of the Brazilian strains, lineage II contained six Peruvian strains isolated between 1992 and 1998, and two strains from western Brazil isolated in 1991, while lineage III comprised four strains isolated in Panama during 1989.
Asunto(s)
Genes Virales , Nucleocápside/genética , Virus Simbu/genética , Animales , Secuencia de Bases , Cartilla de ADN/genética , Humanos , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Orthobunyavirus/clasificación , Orthobunyavirus/genética , Filogenia , ARN Viral/genética , Virus Simbu/clasificación , Virus Simbu/aislamiento & purificación , América del SurRESUMEN
Eastern equine encephalitis virus (EEEV), the sole species in the EEE antigenic complex, is divided into North and South American antigenic varieties based on hemagglutination inhibition tests. Here we describe serologic and phylogenetic analyses of representatives of these varieties, spanning the entire temporal and geographic range available. Nucleotide sequencing and phylogenetic analyses revealed additional genetic diversity within the South American variety; 3 major South/Central American lineages were identified including one represented by a single isolate from eastern Brazil, and 2 lineages with more widespread distributions in Central and South America. All North American isolates comprised a single, highly conserved lineage with strains grouped by the time of isolation and to some extent by location. An EEEV strain isolated during a 1996 equine outbreak in Tamaulipas State, Mexico was closely related to recent Texas isolates, suggesting southward EEEV transportation beyond the presumed enzootic range. Plaque reduction neutralization tests with representatives from the 4 major lineages indicated that each represents a distinct antigenic subtype. A taxonomic revision of the EEE complex is proposed.
Asunto(s)
Variación Antigénica/genética , Virus de la Encefalitis Equina del Este/genética , Encefalomielitis Equina/epidemiología , Variación Genética , Filogenia , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Aves , América Central/epidemiología , Cartilla de ADN/química , ADN Viral/química , Brotes de Enfermedades/veterinaria , Virus de la Encefalitis Equina del Este/inmunología , Caballos , Humanos , Pruebas de Neutralización/veterinaria , América del Norte/epidemiología , ARN Viral/aislamiento & purificación , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/veterinaria , Alineación de Secuencia , Análisis de Secuencia de ARN , Sigmodontinae/virología , América del Sur/epidemiologíaRESUMEN
The safety and immunogenicity of Japanese encephalitis (JE) vaccine (Nakayama strain, monovalent / BIKEN) was studied in 538 U.S. soldiers in 1990. Three doses of vaccine from three consecutively manufactured lots were given on days 0, 7, and either 14 or 30. Serum for antibody determination was drawn at months 0, 2, and 6. Japanese encephalitis plaque reduction neutralization tests were performed by three laboratories on each specimen. Five hundred twenty-eight (98%) participants completed the immunization series. All recipients without antibody before immunization developed neutralizing antibody against JE virus. There were no differences in geometric mean titer among the three test lots at months 2 and 6. Soldiers who received the third dose on day 30 had higher titers at both time points. Antibody to yellow fever had no significant effect on immune response to vaccine. Conclusions drawn from analysis of serologic data from the three labs were nearly identical. Symptoms were generally limited to mild local effects and were reduced in frequency with each subsequent does in the series (21% to 11%; P < 0.0001). Generalized symptoms were rare (e.g., fever = 5%) with no reported cases of anaphylaxis.
Asunto(s)
Encefalitis Japonesa/prevención & control , Vacunas Virales/administración & dosificación , Adulto , Análisis de Varianza , Anticuerpos Antivirales/aislamiento & purificación , Esquema de Medicación , Encefalitis Japonesa/inmunología , Femenino , Humanos , Masculino , Personal Militar , Pruebas de Neutralización , Estados Unidos , Vacunas de Productos Inactivados/administración & dosificación , Vacunas de Productos Inactivados/efectos adversos , Vacunas de Productos Inactivados/inmunología , Vacunas Virales/efectos adversos , Vacunas Virales/inmunología , Fiebre Amarilla/inmunologíaRESUMEN
Attenuated SA14-14-2 Japanese encephalitis (JE) vaccine has been administered safely and effectively to more than 100 million children in China since 1988 and recently, licensure of the vaccine in Korea has been sought. In the first clinical evaluation of the vaccine outside of China, we monitored side effects in 84 children and evaluated antibody responses to a single dose given as primary JE vaccination in 68 children, 1-3 years old (mean age 27 months). No significant adverse events were noted. Neutralizing antibodies (geometric mean titer [GMT] of 188) were produced in 96% of the 68 subjects. In 10 other children who previously had been immunized with two or three doses of inactivated JE vaccine, the booster administration of SA14-14-2 vaccine produced an anamnestic response in all, with a GMT of 3378. In a comparison group of 25 children previously immunized with two doses of inactivated vaccine, neutralizing antibody titers were detected in 16 (64%). Viral specific IgM was detected in nine primary vaccinees (13%) but in others, IgM may have declined to undetectable levels in the four week postimmunization sample. Live attenuated SA14-14-2 JE vaccine is a promising alternative to the only commercially available JE vaccine for national childhood immunization programs in Asia.
Asunto(s)
Virus de la Encefalitis Japonesa (Subgrupo)/inmunología , Encefalitis por Arbovirus/inmunología , Inmunización Secundaria , Vacunas Virales/inmunología , Anticuerpos Antivirales/biosíntesis , Preescolar , Encefalitis por Arbovirus/prevención & control , Humanos , Inmunización Secundaria/efectos adversos , Inmunoglobulina M/sangre , Lactante , Vacunas Atenuadas/efectos adversos , Vacunas Atenuadas/inmunología , Vacunas de Productos Inactivados/efectos adversos , Vacunas de Productos Inactivados/inmunología , Vacunas Virales/efectos adversosRESUMEN
This study investigated the geographic distribution and prevalence of antibodies to California and Bunyamwera serogroup viruses in Native populations of Alaska, and demographic and ecologic risk factors associated with exposure. Sera (n = 1,635) from 18 communities were screened using an ELISA. All age groups were tested for antibodies to Jamestown Canyon (JC), Inkoo (INK), snowshoe hare (SSH), and Northway (NOR) viruses; persons > or = 45 years old (n = 90) from six communities were additionally tested for antibodies to Tahyna (TAH), Batai (BAT), Cache Valley (CV), and Sindbis (SIN) viruses. Thirty free-ranging mammals were tested by a plaque reduction neutralization test (PRNT) for antibodies to all eight viruses and to Getah (GET) virus. In Natives, overall antibody prevalence was 24.9% (JC = 17.6%, monotypic JC = 6.5%, INK = 11.1%, monotypic INK = 0.6%, SSH = 6.8%, monotypic SSH = 3.5%, and NOR = 6.2%). Five TAH, CV, and BAT virus exposures may be serologic cross-reactions, and no SIN virus antibodies were detected. Sindbis-like virus antibodies were found in 30% of the mammals. Most mammals had antibodies to NOR (83.3%) and California serogroup (70.0%) viruses; no GET virus exposures were found. Significant risk factors for human bunyavirus exposures were age group, ethnic-linguistic group, biotic province, climate zone, terrestrial vegetation, and presence of some ungulates and small mammals in communities. Sex was not a significant risk factor.
Asunto(s)
Virus Bunyamwera/inmunología , Infecciones por Bunyaviridae/epidemiología , Virus de la Encefalitis de California/inmunología , Encefalitis de California/epidemiología , Indígenas Norteamericanos , Adolescente , Adulto , Anciano , Alaska/epidemiología , Animales , Anticuerpos Antivirales/sangre , Niño , Preescolar , Ecología , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Mamíferos , Persona de Mediana Edad , Prevalencia , Factores de Riesgo , Estudios SeroepidemiológicosRESUMEN
Yellow fever 17D virus, a safe and effective live, attenuated vaccine, was used as a vector for genes encoding the protective antigenic determinants of a heterologous member of the genus Flavivirus, Japanese encephalitis (JE) virus, the leading cause of acute viral central nervous system infection and death throughout Asia. The viral envelope (prM and E) genes of a full-length cDNA clone of YF 17D virus were replaced with the corresponding genes of JE SA14-14-2, a strain licensed as a live, attenuated vaccine in China. Full-length RNA transcripts of the YF/JE chimaera were used to transfect Vero cells. The progeny virus (named 'ChimeriVax-JE'), was used to define safety after intracerebral (i.c.) inoculation of rhesus monkeys. Monkeys (N = 3) inoculated with a high dose (6.6 log10 pfu) developed a brief viremia, showed no signs of illness, developed high titers of anti-JE neutralizing antibody, and had minimal brain and spinal cord lesion scores according to criteria specified in the WHO monkey neurovirulence test. A control group of 3 monkeys that received a lower dose (4.2 log10 pfu) of commercial YF 17D vaccine had slightly higher lesion scores. To develop a lethal monkey model of JE for vaccine protection tests, we inoculated groups of monkeys i.c. or intranasally (i.n.) with a JE virus strain found to be highly neurovirulent and neuroinvasive for mice. Monkeys inoculated i.c., but not i.n., developed severe encephalitis after an incubation period of 8-13 days. The ChimeriVax-JE virus was passed in a cell line acceptable for human use (diploid fetal rhesus lung) and 4.3 or 5.3 log10 pfu were inoculated into groups of 3 monkeys by the subcutaneous route. All 6 animals developed brief viremias (peak titer < 2.0 log10 pfu/ml) and subsequently had anti-JE but no yellow fever neutralizing antibodies. On day 64, the monkeys were challenged i.c. with 5.5 log10 pfu of virulent JE virus. The immunized animals had no detectable viremia post-challenge, whereas 4 unimmunized controls became viremic. Only 1 of 6 (17%) vaccinated monkeys but 4 of 4 (100%) unvaccinated controls developed encephalitis. Histopathological examination 30 days after challenge confirmed that the protected, immunized animals had no or minimal evidence of encephalitis. These data demonstrated the ability of the ChimeriVax-JE to induce a rapid humoral immune response and to protect against a very severe, direct intracerebral virus challenge. Target areas of neuronal damage and inflammation in monkeys infected IC with wild-type JE, the chimaeric virus and YF 17D were similar, indicating that the histopathological scoring system used for the WHO yellow fever monkey neurovirulence test will be applicable to control testing of chimaeric seed viruses and vaccines.
Asunto(s)
Virus de la Encefalitis Japonesa (Especie)/inmunología , Encefalitis Japonesa/prevención & control , Vacunas Sintéticas/inmunología , Proteínas no Estructurales Virales/inmunología , Proteínas Virales/inmunología , Vacunas Virales/inmunología , Virus de la Fiebre Amarilla/inmunología , Animales , Cápside/genética , Cápside/inmunología , Línea Celular , Sistema Nervioso Central/patología , Sistema Nervioso Central/virología , Relación Dosis-Respuesta Inmunológica , Evaluación Preclínica de Medicamentos , Virus de la Encefalitis Japonesa (Especie)/genética , Virus de la Encefalitis Japonesa (Especie)/crecimiento & desarrollo , Encefalitis Japonesa/patología , Encefalitis Japonesa/virología , Macaca mulatta , Pruebas de Neutralización , Análisis de Secuencia de ADN , Vacunación , Vacunas Atenuadas/administración & dosificación , Vacunas Atenuadas/genética , Vacunas Atenuadas/inmunología , Vacunas Sintéticas/administración & dosificación , Vacunas Sintéticas/genética , Proteínas del Envoltorio Viral/genética , Proteínas del Envoltorio Viral/inmunología , Proteínas no Estructurales Virales/genética , Proteínas Virales/genética , Vacunas Virales/administración & dosificación , Vacunas Virales/genética , Viremia/virología , Virus de la Fiebre Amarilla/genética , Virus de la Fiebre Amarilla/crecimiento & desarrolloAsunto(s)
Síndrome Pulmonar por Hantavirus , Orthohantavirus/fisiología , Roedores/virología , Animales , Reservorios de Enfermedades , Orthohantavirus/aislamiento & purificación , Síndrome Pulmonar por Hantavirus/prevención & control , Síndrome Pulmonar por Hantavirus/transmisión , Síndrome Pulmonar por Hantavirus/veterinaria , Humanos , Investigación , Roedores/fisiologíaRESUMEN
This paper reports the first isolation of Mayaro (MAY) virus from a patient infected in French Guiana. The identification was initially performed using immunofluorescent antibody testing with specific mouse antibody, and confirmed by plaque-reduction neutralization testing and reverse transcription-polymerase chain reaction. To determine if MAY virus infection is widespread in French Guiana, a serosurvey was performed to determine the prevalence of antibody to this virus in various ethnic groups and areas of French Guiana. Human sera (n = 1,962) were screened using the hemagglutination inhibition (HI) test. To determine whether MAY virus circulates in the rain forest, a serosurvey in monkey populations was performed. Monkey sera (n = 150) were also screened for antibody to MAY virus using HI testing. Of the human sera tested, 6.3% were positive for anti-MAY virus antibodies. Significant differences in MAY virus seroprevalence between different age groups were observed. Seroprevalence rates increased with age, with a large increase in people 10-19 years of age in comparison with those less than 10 years of age. After adjustment for age, significant differences were also found between places of residence. The prevalence of anti-MAY virus antibody was higher in people living in contact with the forest, especially in the Haut Oyapock area (odds ratio [OR] = 97.7, 95% confidence interval [CI] = 48.2-197.9) and along the Maroni River (OR = 39.7, 95% CI = 20.6-76.6). The ethnic differences observed in this study were probably due to differences in residence. Among monkeys, higher seroprevalence rates were found in Alouatta seniculus (66.0%) than in Saguinus midas (18.2%). Among Alouatta, the seroprevalence increased significantly with weight (and therefore with age). This study indicates that MAY virus is present in French Guiana, and human infections occur in areas where people live near the tropical rain forest.
Asunto(s)
Infecciones por Alphavirus/epidemiología , Alphavirus/aislamiento & purificación , Anticuerpos Antivirales/sangre , Enfermedades de los Monos/epidemiología , Adolescente , Adulto , Distribución por Edad , Anciano , Anciano de 80 o más Años , Alouatta , Alphavirus/genética , Alphavirus/inmunología , Animales , Niño , Preescolar , Femenino , Técnica del Anticuerpo Fluorescente , Guyana Francesa/epidemiología , Pruebas de Inhibición de Hemaglutinación , Humanos , Lactante , Masculino , Persona de Mediana Edad , Pruebas de Neutralización , Reacción en Cadena de la Polimerasa , Prevalencia , SaguinusRESUMEN
Poxvirus-based recombinant Japanese encephalitis (JE) vaccine candidates, NYVAC-JEV and ALVAC-JEV, were examined for their ability to induce JE virus-specific cytotoxic T lymphocytes (CTLs) in a phase I clinical trial. These vaccine candidates encoded the JE virus premembrane (prM), envelope (E) and non-structural 1 (NS1) proteins. The volunteers received subcutaneous inoculations with each of these candidates on days 0 and 28, and blood was drawn 2 days before vaccination and on day 58. Anti-E and anti-NS1 antibodies were elicited in most vaccinees inoculated with NYVAC-JEV and in some vaccinees inoculated with ALVAC-JEV. Peripheral blood mononuclear cells (PBMCs) obtained from approximately one half of vaccines showed positive proliferation in response to stimulation with live JE virus. Cytotoxic assays demonstrated the presence of JE virus-specific CTLs in in vitro-stimulated PBMCs obtained from two NYVAC-JEV and two ALVAC-JEV vaccinees. Cell depletion tests using PBMCs from one NYVAC-JEV recipient indicated that the phenotype of CTLs was CD8+CD4-.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Virus de la Encefalitis Japonesa (Especie)/inmunología , Linfocitos T Citotóxicos/inmunología , Vacunas Sintéticas/inmunología , Virus Vaccinia/inmunología , Vacunas Virales/inmunología , Adulto , Anticuerpos Antivirales/biosíntesis , Citotoxicidad Inmunológica , Femenino , Humanos , Memoria Inmunológica , Activación de Linfocitos , MasculinoRESUMEN
We determined the prevalence and distribution of Jamestown Canyon (JC) virus antibody in white-tailed deer (Odocoileus virginianus) populations in Connecticut, USA. Sera were collected from hunter-killed deer during 1993. Antibody to JC virus was detected by enzyme-linked immunosorbent assay (ELISA) in 92 (21%) of 446 deer sera, and was uniformly distributed among geographic sites. Twenty-one ELISA-positive sera were tested and confirmed positive by plaque reduction neutralization testing. This represents the first serologic evidence of JC virus in a reservoir host population from the northeastern United States. No cross-reactivity was seen with California encephalitis, Keystone, or snowshoe hare viruses, but a varying degree of cross-reactivity was obtained with Guaroa, Jerry Slough, La-Crosse, San Angelo, and trivittatus viruses. We conclude from this investigation and previous isolations of JC virus from mosquitoes in the state that JC virus occurs enzootically in Connecticut.