RESUMEN

BACKGROUND: Encephalitis is a complex syndrome, and its etiology is often not identified. The California Encephalitis Project was initiated in 1998 to identify the causes and further describe the clinical and epidemiologic characteristics of encephalitis. METHODS: A standardized report form was used to collect demographic and clinical data. Serum, cerebrospinal fluid, and respiratory specimens were obtained prospectively and were tested for the presence of herpesviruses, arboviruses, enteroviruses, measles, respiratory viruses, Chlamydia species, and Mycoplasma pneumoniae. The association between an identified infection and encephalitis was defined using predetermined, organism-specific criteria for confirmed, probable, or possible causes. RESULTS: From 1998 through 2005, a total of 1570 patients were enrolled. Given the large number of patients, subgroups of patients with similar clinical characteristics and laboratory findings were identified. Ten clinical profiles were described. A confirmed or probable etiologic agent was identified for 16% of cases of encephalitis: 69% of these agents were viral; 20%, bacterial; 7%, prion; 3%, parasitic; and 1%, fungal. An additional 13% of cases had a possible etiology identified. Many of the agents classified as possible causes are suspected but have not yet been definitively demonstrated to cause encephalitis; these agents include M. pneumoniae (n=96), influenza virus (n=22), adenovirus (n=14), Chlamydia species (n=10), and human metapneumovirus (n=4). A noninfectious etiology was identified for 8% of cases, and no etiology was found for 63% of cases. CONCLUSIONS: Although the etiology of encephalitis remains unknown in most cases, the recognition of discrete clinical profiles among patients with encephalitis should help focus our efforts toward understanding the etiology, pathogenesis, course, and management of this complex syndrome.

Asunto(s)

Encefalitis/fisiopatología , Proyectos de Investigación/normas , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Encefalitis/microbiología , Encefalitis/virología , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Síndrome , Virus/aislamiento & purificación

RESUMEN

Virtually all in vitro studies of the effects of rhinovirus on human airway epithelium have used cells grown under conditions known to produce low levels of differentiation. The relevance of the results to native epithelium is questionable. Here we grew primary cultures of human tracheal or nasal epithelium under three conditions. One condition produced pseudostratified, mucociliary cells virtually indistinguishable from native epithelium. The other two conditions produced undifferentiated squamous cells lacking cilia. Cells were infected for 6 h with rhinovirus-16. After a 24-h incubation period, we determined levels of viral RNA in the cells, numbers of infectious viral particles released in the mucosal medium, expression of a variety of epithelial cytokines and other proteins, release of IL-6 and IL-8, and transepithelial electrical resistance and voltage. After infection, levels of viral RNA in the poorly differentiated cells were 30 or 130 times those in the differentiated. Furthermore, expression of mRNA for inflammatory cytokines, release of infectious particles, and release of IL-6 and IL-8 were closely correlated with the degree of viral infection. Thus well-differentiated cells are much more resistant to viral infection and its functional consequences than are poorly differentiated cells from the same source.

Asunto(s)

Resfriado Común/inmunología , Células Epiteliales/virología , Mucosa Nasal/citología , Rhinovirus , Tráquea/citología , Diferenciación Celular , Células Cultivadas , Impedancia Eléctrica , Células Epiteliales/citología , Células Epiteliales/metabolismo , Humanos , Inmunidad Innata , Interleucina-6/metabolismo , Interleucina-8/metabolismo , ARN Viral/análisis , Rhinovirus/genética

RESUMEN

A simplified microneutralization procedure is described that uses an empirically determined virus challenge dose, a single dilution of antiserum, and observation of cytopathic effect to determine the adenovirus serotype. The simplified test has faster turnaround time and was 96% concordant with a confirmatory test using serial dilutions of type-specific sera. This method will find utility in high-volume serotyping work.

Asunto(s)

Adenovirus Humanos/clasificación , Infecciones por Adenovirus Humanos/virología , Adenovirus Humanos/aislamiento & purificación , Línea Celular , Efecto Citopatogénico Viral , Humanos , Pruebas de Neutralización , Faringe/virología , Serotipificación

RESUMEN

Adenovirus vaccines have greatly reduced military respiratory disease morbidity since the 1970s. However, in 1995, for economic reasons, the sole manufacturer of these vaccines ceased production. A population-based adenovirus surveillance was established among trainees with acute respiratory illness at 4 US military training centers as the last stores of vaccines were depleted. From October 1996 to June 1998, 1814 (53.1%) of 3413 throat cultures for symptomatic trainees (78% men) yielded adenovirus. Adenovirus types 4, 7, 3, and 21 accounted for 57%, 25%, 9%, and 7% of the isolates, respectively. Unvaccinated trainees were much more likely than vaccinated trainees to be positive for types 4 or 7 (odds ratio [OR] = 28.1; 95% CI, 20.2-39.2). Two training centers experienced epidemics of respiratory disease affecting thousands of trainees when vaccines were not available. Until a new manufacturer is identified, the loss of orphaned adenovirus vaccines will result in thousands of additional preventable adenovirus infections.

Asunto(s)

Infecciones por Adenovirus Humanos/epidemiología , Adenovirus Humanos/aislamiento & purificación , Infecciones por Adenovirus Humanos/prevención & control , Infecciones por Adenovirus Humanos/virología , Adenovirus Humanos/inmunología , Adulto , Brotes de Enfermedades , Humanos , Personal Militar , Vigilancia de la Población , Infecciones del Sistema Respiratorio/epidemiología , Infecciones del Sistema Respiratorio/prevención & control , Infecciones del Sistema Respiratorio/virología , Factores de Tiempo , Vacunas Virales/administración & dosificación , Vacunas Virales/economía

RESUMEN

BACKGROUND: Despite the strong association of asthma exacerbations with rhinovirus (RV) infection, inoculation of asthmatic subjects with RV only causes small changes in lower airway function, suggesting that RV infection is not itself sufficient to provoke asthma exacerbations. OBJECTIVE: Our purpose was to test whether allergic inflammation increases the airway response to RV infection. METHODS: We compared the severity of RV type 16-induced colds in 2 groups of 10 subjects with allergic rhinitis. One group received 3 nasal challenges with allergen and the other received challenges with placebo over the week before nasal inoculation with RV type 16 (4000 tissue culture infective dose 50% per subject). Subjects kept symptom diaries and were assessed with spirometry, methacholine challenge, nasal lavage, and sputum induction on days 2, 4, 7, 10, 15, and 30 after inoculation. RESULTS: The 2 groups developed equal rates of infection (90%), similar cold symptoms (Jackson score median [interquartile range], 11 [6-33] vs 20.5 [6-42] for allergen and placebo groups respectively, P =.54), and similar changes in cellular profile and in IL-6 and IL-8 concentrations in nasal lavage fluid and induced sputum after RV inoculation. The incubation period was significantly longer in the allergen group (2.5 [1-5.5] vs 1 [1-1] day, P =.03) and the duration of cold symptoms was shorter (5 [4-7] vs 8.5 [6-10] days, P =.008). We also found an inverse correlation between the percent of eosinophils in nasal lavage fluid before inoculation and the severity of cold symptoms (r = -0.58, P =. 008). CONCLUSION: In subjects with allergic rhinitis, augmented nasal allergic inflammation before inoculation with RV type 16 does not worsen the severity of cold symptoms but delays their onset and shortens their duration.

Asunto(s)

Resfriado Común/virología , Rinitis Alérgica Perenne/fisiopatología , Rinitis Alérgica Estacional/fisiopatología , Rhinovirus , Adulto , Recuento de Células , Resfriado Común/inmunología , Método Doble Ciego , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mucosa Nasal , Pruebas de Provocación Nasal , Ápice del Flujo Espiratorio , Placebos , Pruebas de Función Respiratoria , Índice de Severidad de la Enfermedad , Pruebas Cutáneas , Esputo/citología , Irrigación Terapéutica

RESUMEN

PURPOSE: Macrolide antibiotics are frequently prescribed to patients with symptoms of a common cold. Despite their lack of proven antiviral activity, macrolide antibiotics may have anti-inflammatory actions, such as inhibition of mucus secretion and production of interleukins 6 and 8 by epithelial cells. Because the symptoms of rhinovirus colds are attributed to the inflammatory response to infection, we studied the effects of treatment with clarithromycin on the symptomatic and inflammatory response to nasal inoculation with rhinovirus. SUBJECTS AND METHODS: We performed a prospective, double-blind, controlled trial in 24 healthy subjects who were seronegative for antibodies to rhinovirus-16. Subjects were randomly assigned to receive either clarithromycin (500 mg) or trimethoprim-sulfamethoxazole (800/160 mg, as a control antibiotic) twice a day for 8 days, beginning 24 hours before inoculation with rhinovirus-16. RESULTS: All 12 subjects in each group were infected and developed symptomatic colds. The groups did not differ in the intensity of cold symptoms (median [25th to 75th percentile] score in the clarithromycin group of 25 [5 to 33] versus 21 [11 to 26] in the trimethoprim-sulfamethoxazole group, P = 0.86), weight of nasal secretions (25 g [8 to 56 g] versus 12 g [5 to 28 g], P = 0.27), or decline in nasal peak flow during the 8 days following viral inoculation. In both groups, similar and significant increases from baseline were observed in the numbers of total cells and neutrophils, and in the concentrations of interleukins 6 and 8, in nasal lavage fluid during the cold. The changes that we observed did not differ from those in an untreated historical control group. CONCLUSIONS: We conclude that clarithromycin treatment has little or no effect on the severity of cold symptoms or the intensity of neutrophilic nasal inflammation in experimental rhinovirus-16 colds.

Asunto(s)

Antibacterianos/uso terapéutico , Claritromicina/uso terapéutico , Resfriado Común/tratamiento farmacológico , Adulto , Antibacterianos/inmunología , Antiinfecciosos/inmunología , Antiinfecciosos/farmacología , Antiinfecciosos/uso terapéutico , Claritromicina/inmunología , Resfriado Común/sangre , Resfriado Común/inmunología , Resfriado Común/virología , Método Doble Ciego , Femenino , Humanos , Inflamación , Interleucina-6/análisis , Interleucina-8/análisis , Recuento de Leucocitos/efectos de los fármacos , Masculino , Líquido del Lavado Nasal/química , Líquido del Lavado Nasal/inmunología , Líquido del Lavado Nasal/virología , Neutrófilos/efectos de los fármacos , Estudios Prospectivos , Rhinovirus/clasificación , Índice de Severidad de la Enfermedad , Combinación Trimetoprim y Sulfametoxazol/inmunología , Combinación Trimetoprim y Sulfametoxazol/farmacología , Combinación Trimetoprim y Sulfametoxazol/uso terapéutico

Asunto(s)

Catolicismo , Investigaciones con Embriones , Embrión de Mamíferos , Regulación Gubernamental , Guías como Asunto , National Institutes of Health (U.S.) , Investigación/legislación & jurisprudencia , Células Madre , Adulto , Financiación Gubernamental , Humanos , Estados Unidos

RESUMEN

BACKGROUND: Molecular characterization of rabies virus has been used to trace spillover transmission from reservoir species to non-reservoir animals and humans (molecular epidemiology), and to monitor emergence of specific strains of the virus into new species and geographic areas (molecular surveillance). OBJECTIVES: To characterize the enzootic strains of rabies virus in California wildlife for epidemiological investigation of transmission to non-reservoir animals and humans. STUDY DESIGN: Molecular characterization was performed on rabies strains from 213 bats, 276 terrestrial animals and one human case, by RT-PCR amplification of the viral nucleocapsid (N) gene followed by Dde I digestion and restriction endonuclease analysis (REA). Brain material from 88 terrestrial animals and 74 bats was stained with a panel of 20 monoclonal antibodies (MABs) directed against the N protein. In order to characterize rabies from very small quantities of brain tissue a nested RT-PCR was developed and evaluated for sensitivity of rabies detection. RESULTS AND CONCLUSIONS: Enzootic terrestrial rabies in California is confined to the Central Valley, the western slope of the Sierra Nevada, and the Central and Northern Pacific Coast Ranges. No terrestrial reservoirs were identified south of the Tehachapi Mountains or east of the Sierra Nevada. Bat strains accounted for rabies in terrestrial animals in these regions. Among terrestrial rabies strains REA identified ten genotypes that segregated geographically and were associated with skunk and fox populations from distinct locations. Co-circulation of three genotypes occurred in Placer County, which had the highest incidence of rabies in skunks. In regions with terrestrial enzootic rabies, the strain from that region accounted for 73% of spillover cases. Bat strains accounted for the remaining 27%. Among terrestrial animals MABs identified three predominant patterns. In rabies strains from bats REA identified ten major and two minor patterns primarily associated with genus and species of bat. Sharing of strains between species was observed. An additional sixteen unclassified REA bat patterns were observed in only one or two individuals of various species. MABs identified four major patterns in bats associated with genus and species of bat with considerable variability. The bat strains most frequently detected in spillover cases throughout California were from the California myotis (Myotis californicus) and Mexican free-tailed bat (Tadarida brasiliensis). Nested RT-PCR increased the detection level of rabies virus 100,000-fold, to 0.03 TCID50.

Asunto(s)

Virus de la Rabia/genética , Rabia/epidemiología , Rabia/virología , Animales , Animales Salvajes/virología , Antígenos Virales/análisis , Encéfalo/virología , California/epidemiología , Quirópteros/virología , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Prohibitinas , Rabia/veterinaria , Virus de la Rabia/aislamiento & purificación , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Zoonosis/virología

RESUMEN

Echovirus type 30 (E30) (genus, Enterovirus; family, Picornaviridae) has caused large outbreaks of aseptic meningitis in many regions of the world in the last 40 years. U.S. enterovirus surveillance data for the period 1961 to 1998 indicated that the annual proportion of E30 isolations relative to total enterovirus isolations has fluctuated widely, from a low of 0% in 1966 to a high of 42% in 1998. Peaks of E30 isolations occurred in the years 1968 to 1969, 1981 to 1984, 1990 to 1993, and 1997 to 1998, coincident with large nationwide outbreaks of E30-associated aseptic meningitis. Analysis of the complete VP1 sequence (876 nucleotides) of 136 E30 strains isolated in geographically dispersed regions of the United States and nine other countries between 1956 and 1998 indicated that the currently circulating E30 strains are genetically distinct from those isolated 30 to 40 years ago. Phylogenetic reconstruction demonstrated the existence of at least four distinct genetic groups, three of which have not been isolated in North America since 1981. Two of the three groups disappeared during periods when E30 was isolated infrequently. All North American E30 strains isolated after 1988 were closely related to one another, and all post-1993 isolates were of the same lineage within this group. Surveillance data indicate that E30 causes large national outbreaks of 2- to 4-year durations, separated by periods of relative quiescence. Our results show that shifts in the overall genetic diversity of E30 and the predominant genetic type correlate temporally with the dynamics of E30 isolation. The sequence data also provide a basis for the application of molecular techniques for future epidemiologic investigations of E30 disease.

Asunto(s)

Infecciones por Echovirus/epidemiología , Enterovirus Humano B/genética , Enterovirus Humano B/aislamiento & purificación , Variación Genética , Meningitis Aséptica/epidemiología , Canadá/epidemiología , Infecciones por Echovirus/virología , Enterovirus Humano B/clasificación , Genotipo , Humanos , Meningitis Aséptica/virología , Datos de Secuencia Molecular , Filogenia , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Secuencia de ADN , Estados Unidos/epidemiología , Proteínas Virales/genética

RESUMEN

We report two cases of human granulocytic ehrlichiosis (HGE) that occurred in northern California in summer 1998. Patients had fever, malaise, and myalgia, reported tick bites, had moderate thrombocytopenia, and had normal or slightly elevated liver enzyme activities. Ehrlichial inclusions were observed in the blood of one patient, and HGE-agent DNA was amplified by PCR from both patients. Genetically, the strains resembled horse isolates from northern California. The close spatial and temporal proximity of the two new cases may be due to a nidus of infection in the area or heightened surveillance by local physicians.

Asunto(s)

Ehrlichia/genética , Ehrlichiosis/microbiología , Granulocitos , Animales , Antibacterianos/uso terapéutico , Secuencia de Bases , California , Gatos , ADN Bacteriano , Doxiciclina/uso terapéutico , Ehrlichia/inmunología , Ehrlichia/aislamiento & purificación , Ehrlichiosis/tratamiento farmacológico , Ehrlichiosis/inmunología , Ehrlichiosis/fisiopatología , Femenino , Células HL-60 , Caballos , Humanos , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , Peromyscus , Análisis de Secuencia de ADN

RESUMEN

Rhinovirus (RV) infections appear to precipitate most asthma exacerbations. To investigate whether RV-16 induces different inflammatory changes in upper and lower airways of asthmatic and healthy subjects, we inoculated 10 nonatopic healthy and 11 atopic asthmatic adults with 2,000 TCID50 RV-16. Subjects recorded symptoms and peak flow daily; and they underwent spirometry, methacholine challenge (PC20), nasal lavage, and sputum induction at baseline and on Days 2, 4, 15, and 29 d after inoculation. One asthmatic subject developed an exacerbation requiring prednisone treatment 5 d after inoculation. The cold symptom severity (Jackson score) did not differ between groups. During the cold, asthma symptoms increased slightly from baseline in the asthmatic group; and PC20 decreased in the healthy group. However, peak flow, bronchodilator use, and spirometry did not change in either group. At baseline, asthmatics had higher neutrophils, eosinophils, and interleukin (IL)-6 in nasal lavage. After inoculation, both groups developed significant increases in nasal neutrophils, IL-6 and IL-8, and modest increases in sputum neutrophils and IL-6, but not IL-8. However, these changes did not differ between groups. IL-5, interferon-gamma, and RANTES were detected only in nasal lavages from two asthmatic subjects, who had the most severe colds. IL-11 was not detected in any sample. We conclude that inflammatory responses of upper and lower airways during RV-16 colds are similar in asthmatic and healthy subjects, and that RV-16 infection is not by itself sufficient to provoke clinical worsening of asthma.

Asunto(s)

Asma/virología , Resfriado Común/virología , Rhinovirus/patogenicidad , Síndrome de Respuesta Inflamatoria Sistémica/virología , Adolescente , Adulto , Anticuerpos Antivirales/metabolismo , Asma/inmunología , Resfriado Común/inmunología , Femenino , Humanos , Interleucinas/metabolismo , Recuento de Leucocitos , Mediciones del Volumen Pulmonar , Masculino , Persona de Mediana Edad , Sistema Respiratorio/inmunología , Sistema Respiratorio/virología , Síndrome de Respuesta Inflamatoria Sistémica/inmunología

RESUMEN

In order to determine the suitability of vaccine strains established in the 1960s for a new vaccine, a comprehensive study of strain variation of adenovirus serotype 4 (AV 4) and AV 7 was undertaken. A 1,500-bp region of the hexon gene containing the AV neutralization epitopes from prototype, vaccine, and community-acquired strains and from wild-type strains from military personnel that cause acute respiratory disease (ARD) was sequenced and analyzed. The whole hexon gene from prototype strains, vaccine strains, and selected isolates was sequenced. AV 7 and AV 7a were found to have distinct genotypes, and all vaccine and wild-type strains recovered from 1963 to 1997 had the AV 7a genotype. There was no significant strain variation in the neutralization epitopes of the AV 7a genotype over a 42-year period. The evolution of AV 4 was more complex, with continuous genetic drift punctuated by replacement with a new strain. The current strain of AV 4, which has been in circulation since 1995, is significantly different from the AV 4 prototype and the vaccine strains. Genetic differences were confirmed to be antigenic differences by neutralization tests, which define the new strain as an AV 4 variant. A type-specific PCR for AV 4, AV 7/7a, and AV 21 was developed, and this PCR facilitated the rapid identification of isolates from outbreaks of ARD.

Asunto(s)

Infecciones por Adenovirus Humanos/virología , Adenovirus Humanos/clasificación , Adenovirus Humanos/patogenicidad , Infecciones del Sistema Respiratorio/virología , Infecciones por Adenovirus Humanos/inmunología , Infecciones por Adenovirus Humanos/prevención & control , Adenovirus Humanos/inmunología , Secuencia de Aminoácidos , Animales , Antígenos Virales/genética , Secuencia de Bases , Cricetinae , Cartilla de ADN/genética , ADN Viral/genética , Brotes de Enfermedades/prevención & control , Variación Genética , Humanos , Personal Militar , Datos de Secuencia Molecular , Pruebas de Neutralización , Reacción en Cadena de la Polimerasa , Infecciones del Sistema Respiratorio/inmunología , Infecciones del Sistema Respiratorio/prevención & control , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido Nucleico , Serotipificación , Especificidad de la Especie , Estados Unidos/epidemiología , Vacunas Virales/genética , Vacunas Virales/inmunología , Vacunas Virales/aislamiento & purificación

RESUMEN

The 1996 production halt of adenovirus types 4 and 7 vaccines prompted concerns about the resurgence of large respiratory disease outbreaks among US military basic trainees. This serosurvey was conducted to assess the current susceptibility of the trainee population to these viruses. A stratified, random sample (n=303) of trainees' sera was tested using a quantitative colorimetric microneutralization assay to demonstrate antibody titers considered to provide immunologic protection against each adenovirus type. Results were analyzed for relationships between susceptibility and 4 demographic factors-gender, race, prior military service, and age. Results showed that 66% and 73% of trainees were susceptible to serotypes 4 and 7, respectively. Nearly 90% were susceptible to at least one serotype. Susceptibility was significantly (P<.05) related to lack of prior military service and younger age. Consistent with a serosurvey conducted 20 years ago, these results demonstrated significant susceptibility to two vaccine-preventable causes of disease. These findings may have civilian implications.

Asunto(s)

Infecciones por Adenovirus Humanos/epidemiología , Adenovirus Humanos/inmunología , Anticuerpos Antivirales/sangre , Personal Militar , Infecciones por Adenovirus Humanos/sangre , Infecciones por Adenovirus Humanos/inmunología , Adulto , Femenino , Humanos , Masculino , Prevalencia , Estudios Retrospectivos , Estudios Seroepidemiológicos , Estados Unidos/epidemiología

RESUMEN

During 1993, 66 small animal practices participated in a prospective study to evaluate the incidence and details of anesthetic-related morbidity and mortality. Considering a total of 8,087 dogs and 8,702 cats undergoing anesthesia, the incidences of complications were 2.1% and 1.3%, respectively. Death occurred in 0.11% and 0.1% of cases, respectively. Logistic regression models were developed and showed that a significant odds ratio (OR) of complications in dogs was associated with xylazine (OR, 91.5); heart rate monitoring (OR, 3.2); American Society of Anesthesiologists (ASA) 3, 4, or 5 classification (OR, 2.5); isoflurane (OR, 2.4); butorphanol (OR, 0.35); technician presence (OR, 0.26); acepromazine (OR, 0.24); ketamine (OR, 0.21); and mask induction (OR, 0.2). Complications in cats were associated with ASA 3, 4, or 5 classification (OR, 5.3); diazepam (OR, 4.1); intubation (OR, 1.7); butorphanol (OR, 0.45); and ketamine (OR, 0.17). Cardiac arrest in dogs was associated with xylazine (OR, 43.6) and ASA 3, 4, or 5 classification (OR, 7.1). Cardiac arrest in cats was associated with ASA 3, 4, or 5 classification (OR, 21.6) and technician presence (OR, 0.19). This paper reports the incidences of complications and cardiac arrest in small animal practice and identifies common complications and factors that may influence anesthetic morbidity and mortality. This information may be useful in comparing anesthetic management practices.

Asunto(s)

Anestesia/veterinaria , Gatos , Perros , Medicina Veterinaria/estadística & datos numéricos , Anestesia/mortalidad , Anestesia/estadística & datos numéricos , Anestésicos , Animales , Enfermedades de los Gatos/epidemiología , Enfermedades de los Gatos/etiología , Gatos/cirugía , Recolección de Datos , Enfermedades de los Perros/epidemiología , Enfermedades de los Perros/etiología , Perros/cirugía , Paro Cardíaco/epidemiología , Paro Cardíaco/etiología , Paro Cardíaco/veterinaria , Incidencia , Modelos Logísticos , Monitoreo Fisiológico/veterinaria , Morbilidad , Ontario/epidemiología , Medicación Preanestésica/veterinaria , Estudios Prospectivos

RESUMEN

A seroprevalence survey to recently proposed adenovirus (AV) serotypes AV 48 and AV 49, isolated primarily from AIDS patients, was conducted among the San Francisco Men's Health Study cohort. This cohort of homosexual, heterosexual, or bisexual HIV-seronegative and -seropositive men from selected San Francisco census tracts has been studied since 1984. The presence or absence of type-specific antibody in 628 serum specimens from 1989 was determined by microneutralization. Thirty of these subjects (26 positive and four negative) were studied longitudinally. Serum specimens taken at 6-month intervals from 1984 to 1993 were tested to characterize antibody response and to document the advent of these new serotypes. Eight subjects were tested against five other AV serotypes for comparison. AV 48 and AV 49 seroprevalence rates were significantly higher in HIV-seropositives, but infection was not limited to the immunocompromised. Sexual preference was not a significant determinant for AV seroprevalence in HIV-seronegatives. However, the extent and duration of the neutralizing antibody response was strikingly different between homosexuals and heterosexuals: an endemic pattern of continuous reexposure over the 9-year period was seen in 90% of 19 homosexuals, while five of six heterosexuals (83%) had an episodic pattern of exposure with antibody decline to undetectable levels. These data suggest that these viruses may be endemic in some part of the homosexual population and that sexual transmission may be the primary source of continuous reexposure.

Asunto(s)

Infecciones Oportunistas Relacionadas con el SIDA/virología , Infecciones por Adenoviridae/virología , Adenovirus Humanos/aislamiento & purificación , Infecciones Oportunistas Relacionadas con el SIDA/sangre , Infecciones Oportunistas Relacionadas con el SIDA/inmunología , Infecciones por Adenoviridae/epidemiología , Infecciones por Adenoviridae/inmunología , Adenovirus Humanos/inmunología , Adulto , Estudios de Cohortes , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Pruebas de Neutralización , San Francisco/epidemiología

RESUMEN

The origin of AIDS-associated adenoviruses (AV 43-AV 49) was investigated by examining evolutionary relationships among 18 serologically related subgenus D serotypes and 3 intermediates and determining the mutation rate of a single serotype, AV 48, among clinical isolates from AIDS patients over a 6-year period. Nucleotide sequence of conserved and seven hypervariable regions (HVRs) of the hexon protein, the pVI core protein signal peptide, and noncoding region between the two genes was determined. Among AV 48 isolates the base misincorporation rate was 3.2 per 10,000 bases over 6 years. A 6-bp deletion occurred in one isolate between short direct repeats in HVR 7. Among subgenus D serotypes mutation rates were extremely low in the pVI peptide, the 5' hexon noncoding region, and first 187 bases of hexon protein. Small 2- and 3-bp deletions between short direct repeats in a polypurine stretch in the noncoding region occurred in 3 strains. Mutation increased with proximity to the HVRs. Within HVR 1, 2, 4, 5, and 7 variability consisted of extensive intrachromosomal illegitimate recombination, including deletions between short direct repeats, insertions and duplications in repetitive polypurine stretches, and numerous base substitutions. All serotypes and intermediates differed by at least one illegitimate recombination event, with one exception. We conclude that AV serotype evolution is driven by illegitimate recombination events (antigenic shift), concommitant with single base mutation (antigenic drift), and that the HVRs are "hot spots" for both. These events could be explained by slippage-misalignment of the AV DNA polymerase in repetitive polypurine stretches during single-strand DNA replication. This mutability in the surface regions of the major viral coat protein confers a distinct survival advantage to this family of viruses.

Asunto(s)

Adenovirus Humanos/genética , Proteínas de la Cápside , Cápside/genética , Evolución Molecular , Recombinación Genética , Adenovirus Humanos/clasificación , Adenovirus Humanos/aislamiento & purificación , Secuencia de Aminoácidos , Secuencia de Bases , ADN Viral , Humanos , Datos de Secuencia Molecular , Mutagénesis , Homología de Secuencia de Ácido Nucleico , Serotipificación

RESUMEN

The first full-length hexon protein DNA and deduced amino acid sequences of a subgenus D adenovirus (AV) were determined from candidate AV48 (85-0844). Comprehensive comparison of this sequence with hexon protein sequences from human subgenera A, B, C, D, F, bovine AV3, and mouse AV1 revealed seven discrete hypervariable regions (HVRs) among the 250 variable residues in loops 1 and 2. These regions differed in length between serotypes, from 2 to 38 residues, and contained > 00% of hexon serotype-specific residues among human serotypes. Alignment with the published crystal structure of AV2 established the location and structure of the type-specific regions. Five HVRs were shown to be part of linear loops on the exposed surfaces of the protein, analogous to the serotype-specific loops or "puffs" in picornavirus capsid proteins. The HVRs were supported by a common framework of conserved residues, of which 68 to 75% were hydrophobic. Unique sequences were limited to the seven HVRs, so that one or more of these regions contain the type-specific neutralization epitopes. A neutralizing AV48 hexon-specific antiserum recognized linear peptides that corresponded to six HVRs by enzyme immunoassay. Affinity-purification removal of all peptide-reactive antibodies did not significantly decrease the neutralization titer. Eluted peptide-reactive antibodies did not neutralize. Human antisera that neutralized AV48 did not recognize linear peptides. Purified trimeric native hexon inhibited neutralization, but monomeric heat-denatured hexon did not. We conclude that the AV48 neutralization epitope(s) is complex and conformational.

Asunto(s)

Adenovirus Humanos/química , Proteínas de la Cápside , Cápside/química , Adenovirus Humanos/clasificación , Adenovirus Humanos/genética , Adenovirus Humanos/inmunología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Sitios de Unión , Cápside/genética , Cápside/inmunología , Bovinos , Secuencia Conservada , Ensayo de Inmunoadsorción Enzimática , Humanos , Ratones , Datos de Secuencia Molecular , Pruebas de Neutralización , Unión Proteica , Conformación Proteica , Conejos , Homología de Secuencia de Aminoácido , Serotipificación

RESUMEN

Ten presumptive enterovirus isolates which could not be neutralized by type specific antisera to any prototype enterovirus were related to echovirus 22 using molecular, biologic and serologic methods. Viral protein fingerprinting and PCR first suggested that these strains were variants of echovirus 22. Three of the strains were echovirus 22 prime strains, i.e., antiserum made to the variant strain neutralized the variant and the prototype strain. The other strains were neutralized by antiserum to the prime strains. Unlike typical enteroviruses, echovirus 22 and 23 prototype viruses and 7 of the 10 variants were heat stable at 50 degrees C in H2O for 1 h.

Asunto(s)

Enterovirus Humano B/clasificación , Enterovirus Humano B/genética , Variación Genética , Filogenia , Animales , Línea Celular , Preescolar , Infecciones por Echovirus/virología , Enterovirus Humano B/aislamiento & purificación , Femenino , Humanos , Lactante , Masculino , Reacción en Cadena de la Polimerasa/métodos , Células Tumorales Cultivadas , Proteínas Virales/análisis

RESUMEN

A mixture of adenoviruses 31 and 49 was isolated from the brain of an AIDS patient with encephalitis. Adenovirus hexon protein was detected in neurons by indirect immunofluorescence. By restriction endonuclease analysis both adenovirus 31 and 49 were shown to be new genotypes. This is the first report of the isolation of a mixture of adenoviruses from adenovirus encephalitis and the first association of adenovirus 49, a new candidate serotype, with encephalitis.

Asunto(s)

Infecciones Oportunistas Relacionadas con el SIDA/virología , Infecciones por Adenovirus Humanos/virología , Adenovirus Humanos/aislamiento & purificación , Proteínas de la Cápside , Encefalitis Viral/virología , Infecciones Oportunistas Relacionadas con el SIDA/complicaciones , Infecciones por Adenovirus Humanos/complicaciones , Adenovirus Humanos/clasificación , Antígenos Virales/inmunología , Encéfalo/patología , Encéfalo/virología , Cápside/inmunología , Línea Celular , Encefalitis Viral/complicaciones , Resultado Fatal , Femenino , Genotipo , Humanos , Persona de Mediana Edad , Serotipificación , Células Tumorales Cultivadas

RESUMEN

The purpose of this study was to develop a technique to measure the oxygen cost of ventilation and the values of ventilatory parameters in seven normal horses rebreathing carbon dioxide (CO2). All the horses responded to increased inspiratory levels of CO2 by increasing their tidal volume (VT) and frequency of breathing (Vf). The mean (SE) oxygen cost litre-1 of ventilation, measured at rates of ventilation greater than 200 litres min-1 was 1.7 (0.04) ml litre-1, similar to that of normal human subjects ventilating submaximally. It was concluded that the CO2 rebreathing test is a practical, non-invasive means of measuring the oxygen cost of breathing and the ventilatory response to CO2 in horses.

Asunto(s)

Caballos/fisiología , Consumo de Oxígeno , Respiración , Animales , Dióxido de Carbono/análisis , Humanos , Análisis de Regresión , Descanso