RESUMEN
We report the results of an investigation of a small outbreak of hantavirus pulmonary syndrome in 2002 in the Department of Santa Cruz, Bolivia, where the disease had not previously been reported. Two cases were initially reported. The first case was a physician infected with Laguna Negra virus during a weekend visit to his ranch. Four other persons living on the ranch were IgM antibody-positive, two of whom were symptomatic for mild hantavirus pulmonary syndrome. The second case was a migrant sugarcane worker. Although no sample remained to determine the specific infecting hantavirus, a virus 90% homologous with Río Mamoré virus was previously found in small-eared pygmy rice rats (Oligoryzomys microtis) trapped in the area. An antibody prevalence study conducted in the region as part of the outbreak investigation showed 45 (9.1%) of 494 persons to be IgG positive, illustrating that hantavirus infection is common in Santa Cruz Department. Precipitation in the months preceding the outbreak was particularly heavy in comparison to other years, suggesting a possible climatic or ecological influence on rodent populations and risk of hantavirus transmission to humans. Hantavirus infection appears to be common in the Santa Cruz Department, but more comprehensive surveillance and field studies are needed to fully understand the epidemiology and risk to humans.
Asunto(s)
Anticuerpos Antivirales/sangre , Brotes de Enfermedades , Síndrome Pulmonar por Hantavirus/epidemiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Bolivia/epidemiología , Niño , Preescolar , Femenino , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Masculino , Persona de Mediana Edad , Estudios Seroepidemiológicos , Tiempo (Meteorología) , Adulto JovenRESUMEN
BACKGROUND: Knowledge of spatial patterns of dengue virus (DENV) infection is important for understanding transmission dynamics and guiding effective disease prevention strategies. Because movement of infected humans and mosquito vectors plays a role in the spread and persistence of virus, spatial dimensions of transmission can range from small household foci to large community clusters. Current understanding is limited because past analyses emphasized clinically apparent illness and did not account for the potentially large proportion of inapparent infections. In this study we analyzed both clinically apparent and overall infections to determine the extent of clustering among human DENV infections. METHODOLOGY/PRINCIPAL FINDINGS: We conducted spatial analyses at global and local scales, using acute case and seroconversion data from a prospective longitudinal cohort in Iquitos, Peru, from 1999-2003. Our study began during a period of interepidemic DENV-1 and DENV-2 transmission and transitioned to epidemic DENV-3 transmission. Infection status was determined by seroconversion based on plaque neutralization testing of sequential blood samples taken at approximately six-month intervals, with date of infection assigned as the middate between paired samples. Each year was divided into three distinct seasonal periods of DENV transmission. Spatial heterogeneity was detected in baseline seroprevalence for DENV-1 and DENV-2. Cumulative DENV-3 seroprevalence calculated by trimester from 2001-2003 was spatially similar to preexisting DENV-1 and DENV-2 seroprevalence. Global clustering (case-control Ripley's K statistic) appeared at radii of â¼200-800 m. Local analyses (Kuldorf spatial scan statistic) identified eight DENV-1 and 15 DENV-3 clusters from 1999-2003. The number of seroconversions per cluster ranged from 3-34 with radii from zero (a single household) to 750 m; 65% of clusters had radii >100 m. No clustering was detected among clinically apparent infections. CONCLUSIONS/SIGNIFICANCE: Seroprevalence of previously circulating DENV serotypes can be a predictor of transmission risk for a different invading serotype and, thus, identify targets for strategically placed surveillance and intervention. Seroprevalence of a specific serotype is also important, but does not preclude other contributing factors, such as mosquito density, in determining where transmission of that virus will occur. Regardless of the epidemiological context or virus serotype, human movement appears to be an important factor in defining the spatial dimensions of DENV transmission and, thus, should be considered in the design and evaluation of surveillance and intervention strategies.
Asunto(s)
Análisis por Conglomerados , Virus del Dengue/clasificación , Virus del Dengue/aislamiento & purificación , Dengue/epidemiología , Dengue/transmisión , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/sangre , Niño , Preescolar , Estudios de Cohortes , Dengue/virología , Virus del Dengue/genética , Femenino , Geografía , Humanos , Lactante , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Pruebas de Neutralización , Perú/epidemiología , Estudios Prospectivos , Estudios Seroepidemiológicos , Serotipificación , Ensayo de Placa Viral , Adulto JovenRESUMEN
We conducted a prospective, inpatient fever study in malaria-endemic Papua, Indonesia to determine non-malaria fever etiologies. Investigations included malaria blood films, blood culture, paired serologic samples analysis for dengue, Japanese encephalitis, leptospirosis, scrub typhus, murine typhus, and spotted fever group rickettsia. During 1997-2000, 226 patients (127 males and 99 females) 1-80 years of age (median age = 25 years) were enrolled. Positive blood cultures (n = 34, 15%) were obtained for Salmonella Typhi (n = 13), Escherichia coli (n = 8), Streptococcus pneumoniae (n = 6), Staphylococcus aureus (n = 5), Streptococcus pyogenes (n = 1), and Klebsiella pneumoniae (n = 1). Twenty (8.8%) patients were positive for leptospirosis by polymerase chain reaction. Eighty (35.4%) of 226 patients had ≥ 1 positive serology, diagnostic for 15 rickettsial and 9 dengue cases. Acid-fast bacilli-positive sputum was obtained from three patients. Most common confirmed (81 of 226, 35.8%)/suspected diagnoses were typhoid fever (n = 41), pneumonia (n = 29), leptospirosis (n = 28), urinary tract infections (n = 20), rickettsioses (n = 19), dengue (n = 17), and meningitis/encephalitis (n = 15). There were 17 deaths, 7 (46.7%) were caused by meningitis/encephalitis. Multiple positive serologic results and few confirmed diagnoses indicate the need for improved diagnostics.
Asunto(s)
Infecciones Bacterianas/complicaciones , Fiebre/epidemiología , Fiebre/etiología , Virosis/complicaciones , Enfermedad Aguda , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Bacteriemia/complicaciones , Bacteriemia/epidemiología , Bacteriemia/microbiología , Bacteriemia/mortalidad , Infecciones Bacterianas/epidemiología , Infecciones Bacterianas/microbiología , Infecciones Bacterianas/mortalidad , Infecciones del Sistema Nervioso Central/complicaciones , Infecciones del Sistema Nervioso Central/epidemiología , Infecciones del Sistema Nervioso Central/etiología , Infecciones del Sistema Nervioso Central/mortalidad , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Papúa Nueva Guinea/epidemiología , Virosis/epidemiología , Virosis/mortalidad , Virosis/virología , Adulto JovenRESUMEN
Although encephalomyocarditis virus (EMCV) infection has been commonly documented among domestic animals, less is known about EMCV transmission among humans. Recently, we described the isolation of EMCV from two febrile patients in Peru. To further investigate EMCV transmission in Peru, we screened febrile patients reporting to health clinics in Peru for serological evidence of recent EMCV infection. We also conducted a serological survey for EMCV-neutralizing antibodies in the city of Iquitos, located in the Amazon basin department of Loreto, Peru. Additionally, we screened serum from rodents collected from 10 departments in Peru for evidence of EMCV exposure. EMCV infection was found to be only rarely associated with acute febrile disease in Peru, accounting for <1% of febrile episodes analyzed. Despite the low acute disease burden associated with the virus, human exposure was quite common, as prevalence of EMCV-neutralizing antibodies ranged between 6.0% in the coastal city of Tumbes and >17% in cities in the tropical rainforest of northeastern Peru (Iquitos and Yurimaguas). On the basis of the serological survey conducted in Iquitos, risk factors for past infection include increased age, socioeconomic indicators such as residence construction materials and neighborhood, and swine ownership. Evidence from the rodent survey indicates that EMCV exposure is common among Murinae subfamily rodents in Peru (9.4% EMCV IgG positive), but less common among Sigmodontinae rodents (1.0% positive). Further studies are necessary to more precisely delineate the mode of EMCV transmission to humans, other potential disease manifestations, and the economic impact of EMCV transmission among swine in Peru.
Asunto(s)
Anticuerpos Antivirales/sangre , Infecciones por Cardiovirus/epidemiología , Virus de la Encefalomiocarditis/inmunología , Murinae/virología , Sigmodontinae/virología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Animales , Infecciones por Cardiovirus/sangre , Infecciones por Cardiovirus/transmisión , Niño , Preescolar , Virus de la Encefalomiocarditis/aislamiento & purificación , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Modelos Logísticos , Masculino , Persona de Mediana Edad , Perú/epidemiología , Prevalencia , Factores de Riesgo , Adulto JovenRESUMEN
BACKGROUND: Arthropod-borne viruses (arboviruses) are among the most common agents of human febrile illness worldwide and the most important emerging pathogens, causing multiple notable epidemics of human disease over recent decades. Despite the public health relevance, little is know about the geographic distribution, relative impact, and risk factors for arbovirus infection in many regions of the world. Our objectives were to describe the arboviruses associated with acute undifferentiated febrile illness in participating clinics in four countries in South America and to provide detailed epidemiological analysis of arbovirus infection in Iquitos, Peru, where more extensive monitoring was conducted. METHODOLOGY/FINDINGS: A clinic-based syndromic surveillance system was implemented in 13 locations in Ecuador, Peru, Bolivia, and Paraguay. Serum samples and demographic information were collected from febrile participants reporting to local health clinics or hospitals. Acute-phase sera were tested for viral infection by immunofluorescence assay or RT-PCR, while acute- and convalescent-phase sera were tested for pathogen-specific IgM by ELISA. Between May 2000 and December 2007, 20,880 participants were included in the study, with evidence for recent arbovirus infection detected for 6,793 (32.5%). Dengue viruses (Flavivirus) were the most common arbovirus infections, totaling 26.0% of febrile episodes, with DENV-3 as the most common serotype. Alphavirus (Venezuelan equine encephalitis virus [VEEV] and Mayaro virus [MAYV]) and Orthobunyavirus (Oropouche virus [OROV], Group C viruses, and Guaroa virus) infections were both observed in approximately 3% of febrile episodes. In Iquitos, risk factors for VEEV and MAYV infection included being male and reporting to a rural (vs urban) clinic. In contrast, OROV infection was similar between sexes and type of clinic. CONCLUSIONS/SIGNIFICANCE: Our data provide a better understanding of the geographic range of arboviruses in South America and highlight the diversity of pathogens in circulation. These arboviruses are currently significant causes of human illness in endemic regions but also have potential for further expansion. Our data provide a basis for analyzing changes in their ecology and epidemiology.
Asunto(s)
Infecciones por Arbovirus/epidemiología , Infecciones por Arbovirus/virología , Arbovirus/clasificación , Fiebre de Origen Desconocido/epidemiología , Fiebre de Origen Desconocido/etiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Antivirales/sangre , Infecciones por Arbovirus/patología , Arbovirus/aislamiento & purificación , Niño , Preescolar , Ensayo de Inmunoadsorción Enzimática , Femenino , Técnica del Anticuerpo Fluorescente Directa , Humanos , Inmunoglobulina M/sangre , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Prevalencia , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , América del Sur/epidemiología , Adulto JovenRESUMEN
BACKGROUND: Comprehensive, longitudinal field studies that monitor both disease and vector populations for dengue viruses are urgently needed as a pre-requisite for developing locally adaptable prevention programs or to appropriately test and license new vaccines. METHODOLOGY AND PRINCIPAL FINDINGS: We report the results from such a study spanning 5 years in the Amazonian city of Iquitos, Peru where DENV infection was monitored serologically among approximately 2,400 members of a neighborhood-based cohort and through school-based absenteeism surveillance for active febrile illness among a subset of this cohort. At baseline, 80% of the study population had DENV antibodies, seroprevalence increased with age, and significant geographic variation was observed, with neighborhood-specific age-adjusted rates ranging from 67.1 to 89.9%. During the first 15 months, when DENV-1 and DENV-2 were co-circulating, population-based incidence rates ranged from 2-3 infections/100 person-years (p-years). The introduction of DENV-3 during the last half of 2001 was characterized by 3 distinct periods: amplification over at least 5-6 months, replacement of previously circulating serotypes, and epidemic transmission when incidence peaked at 89 infections/100 p-years. CONCLUSIONS/SIGNIFICANCE: Neighborhood-specific baseline seroprevalence rates were not predictive of geographic incidence patterns prior to the DENV-3 introduction, but were closely mirrored during the invasion of this serotype. Transmission varied geographically, with peak incidence occurring at different times among the 8 geographic zones in approximately 16 km(2) of the city. The lag from novel serotype introduction to epidemic transmission and knowledge of spatially explicit areas of elevated risk should be considered for more effective application of limited resources for dengue prevention.
Asunto(s)
Anticuerpos Antivirales/sangre , Virus del Dengue/inmunología , Dengue/epidemiología , Dengue/transmisión , Absentismo , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Estudios de Cohortes , Femenino , Fiebre de Origen Desconocido/epidemiología , Geografía , Humanos , Incidencia , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Perú/epidemiología , Estudios Seroepidemiológicos , Adulto JovenRESUMEN
We conducted a longitudinal observational study of 533 patients presenting to two hospitals in the Ecuadorean Amazon basin with acute undifferentiated febrile illness (AUFI) from 2001 through 2004. Viral isolation, reverse transcription-polymerase chain reaction (RT-PCR), IgM seroconversion, and malaria smears identified pathogens responsible for fever in 122 (40.1%) of 304 patients who provided both acute and convalescent blood samples. Leptospirosis was found in 40 (13.2%), malaria in 38 (12.5%), rickettsioses in 18 (5.9%), dengue fever in 16 (5.3%), Q fever in 15 (4.9%), brucellosis in 4 (1.3%), Ilhéus infection in 3 (1.0%), and Venezuelan equine encephalitis (VEE), Oropouche, and St. Louis encephalitis virus infections in less than 1% of these patients. Viral isolation and RT-PCR on another 229 participants who provided only acute samples identified 3 cases of dengue fever, 2 of VEE, and 1 of Ilhéus. None of these pathogens, except for malaria, had previously been detected in the study area.
Asunto(s)
Fiebre/etiología , Enfermedad Aguda , Adolescente , Adulto , Anciano , Niño , Preescolar , Dengue/fisiopatología , Humanos , Lactante , Recién Nacido , Leptospirosis/fisiopatología , Estudios Longitudinales , Malaria/fisiopatología , Persona de Mediana Edad , Fiebre Q/fisiopatologíaRESUMEN
Endemic dengue transmission has been documented in the Amazonian city of Iquitos, Peru, since the early 1990s. To better understand the epidemiology of dengue transmission in Iquitos, we established multiple active surveillance systems to detect symptomatic infections. Here we compare the efficacy of distinct community-based (door to door) and school absenteeism-based febrile surveillance strategies in detecting active cases of dengue. Febrile episodes were detected by both systems with equal rapidity after disease onset. However, during the period that both programs were running simultaneously in 2004, a higher number of febrile cases in general (4.52/100 versus 1.64/100 person-years) and dengue cases specifically (2.35/100 versus 1.29/100 person-years) were detected in school-aged children through the community-based surveillance program. Similar results were obtained by direct comparison of 435 participants concurrently enrolled in both programs (P < 0.005). We conclude that, in Iquitos, community-based door-to-door surveillance is a more efficient and sensitive design for detecting active dengue cases than programs based on school absenteeism.
Asunto(s)
Dengue/epidemiología , Vigilancia de la Población/métodos , Adolescente , Niño , Preescolar , Estudios de Cohortes , Femenino , Humanos , Masculino , Perú/epidemiología , Instituciones AcadémicasRESUMEN
In 2001, we began a prospective longitudinal study in a cohort of schoolchildren 5-13 years of age residing in Maracay, Venezuela, to determine the cumulative incidence of dengue virus (DENV) infections by virus serotype. This report presents serological data from 710 schoolchildren who were tested during the first 2 years of the study. Serological evaluations were conducted by plaque reduction neutralization test (PRNT). At study initiation, 51% of children had PRNT antibody titers against one (30.1% = 13.4% DENV-1, 14.2% DENV-2, 0.6% DENV-3, and 2% DENV-4) or multiple DENV serotypes (20.9%). By the end of the first year, 89 of 348 (25.6%) PRNT-negative children seroconverted, and 94 of 362 (26%) who were PRNT-positive in their baseline sera tested positive for additional serotypes, for an overall cumulative incidence of DENV infections of 25.8%. By serotype, the percentages found were 1.4% DENV-1, 1.4% DENV-2, 19% DENV-3, and 1.2% DENV-4. In the second year, 37 of 259 (14.3%) PRNT-negative children seroconverted, and 83 of 451 (18.4%) who had monotypic and multitypic PRNT patterns in their baseline sera exhibited additional serotype seroconversions, for an overall cumulative incidence of DENV infections of 16.9%. By serotype, the percentages found were 0.8% DENV-1, 1.5% DENV-2, 8.5% DENV-3, and 2.3% DENV-4. Overall, these results suggest a high cumulative incidence of DENV infections among 5-13-year-old school children in Maracay, Venezuela.
Asunto(s)
Anticuerpos Antivirales/sangre , Virus del Dengue/aislamiento & purificación , Dengue/epidemiología , Enfermedades Endémicas/estadística & datos numéricos , Adolescente , Anticuerpos Antivirales/inmunología , Niño , Preescolar , Estudios de Cohortes , Dengue/inmunología , Virus del Dengue/inmunología , Femenino , Humanos , Incidencia , Estudios Longitudinales , Masculino , Pruebas de Neutralización , Estudios Prospectivos , Estudios Seroepidemiológicos , Pruebas Serológicas , Serotipificación , Venezuela/epidemiologíaRESUMEN
A small focus of hemorrhagic fever (HF) cases occurred near Cochabamba, Bolivia, in December 2003 and January 2004. Specimens were available from only one fatal case, which had a clinical course that included fever, headache, arthralgia, myalgia, and vomiting with subsequent deterioration and multiple hemorrhagic signs. A non-cytopathic virus was isolated from two of the patient serum samples, and identified as an arenavirus by IFA staining with a rabbit polyvalent antiserum raised against South American arenaviruses known to be associated with HF (Guanarito, Machupo, and Sabiá). RT-PCR analysis and subsequent analysis of the complete virus S and L RNA segment sequences identified the virus as a member of the New World Clade B arenaviruses, which includes all the pathogenic South American arenaviruses. The virus was shown to be most closely related to Sabiá virus, but with 26% and 30% nucleotide difference in the S and L segments, and 26%, 28%, 15% and 22% amino acid differences for the L, Z, N, and GP proteins, respectively, indicating the virus represents a newly discovered arenavirus, for which we propose the name Chapare virus. In conclusion, two different arenaviruses, Machupo and Chapare, can be associated with severe HF cases in Bolivia.
Asunto(s)
Arenavirus del Nuevo Mundo/aislamiento & purificación , Fiebre Hemorrágica Americana/virología , Adulto , Arenavirus del Nuevo Mundo/clasificación , Arenavirus del Nuevo Mundo/genética , Bolivia , Análisis por Conglomerados , Diagnóstico Diferencial , Resultado Fatal , Genoma Viral , Fiebre Hemorrágica Americana/diagnóstico , Humanos , Masculino , Filogenia , ARN Viral/genética , Análisis de Secuencia , Homología de Secuencia de Aminoácido , Dengue Grave/diagnóstico , Proteínas Virales , Fiebre Amarilla/diagnósticoAsunto(s)
Infecciones por Flavivirus/genética , Flavivirus/genética , Flavivirus/aislamiento & purificación , Adulto , Ecuador , Flavivirus/clasificación , Flavivirus/patogenicidad , Infecciones por Flavivirus/sangre , Infecciones por Flavivirus/diagnóstico , Humanos , Masculino , Personal Militar , Datos de Secuencia MolecularRESUMEN
A dengue (DEN) virus type 3 DNA vaccine expressing pre-membrane and envelope genes was tested for immunogenicity and protective efficacy in Aotus monkeys. Five of six vaccinated animals demonstrated moderate DEN-specific antibody responses as measured by ELISA and virus neutralization in vitro. By contrast, none of the six control animals developed detectable anti-DEN antibodies. When five vaccinated animals were challenged with live DEN-3 virus and viremia determined by PCR amplification of viral RNA in serum samples, one animal was completely protected and two were partially protected as indicated by a decrease in mean days of viremia. The results demonstrate the ability of the DEN-3 DNA vaccine to elicit a neutralizing antibody response and to partially protect against live virus challenge. These findings support the inclusion of this construct in a tetravalent DNA vaccine.
Asunto(s)
Dengue/inmunología , Dengue/prevención & control , Vacunas de ADN/inmunología , Proteínas del Envoltorio Viral/inmunología , Vacunas Virales/inmunología , Animales , Anticuerpos Antivirales/sangre , Antígenos Virales/genética , Antígenos Virales/inmunología , Aotidae , Virus del Dengue/genética , Virus del Dengue/inmunología , Modelos Animales de Enfermedad , Ensayo de Inmunoadsorción Enzimática , Humanos , Pruebas de Neutralización , ARN Viral/sangre , Vacunas de ADN/administración & dosificación , Proteínas del Envoltorio Viral/genética , Vacunas Virales/administración & dosificaciónRESUMEN
HIV cross-sectional studies were conducted among high-risk populations in 9 countries of South America. Enzyme-linked immunosorbent assay screening and Western blot confirmatory testing were performed, and env heteroduplex mobility assay genotyping and DNA sequencing were performed on a subset of HIV-positive subjects. HIV prevalences were highest among men who have sex with men (MSM; 2.0%-27.8%) and were found to be associated with multiple partners, noninjection drug use (non-IDU), and sexually transmitted infections (STIs). By comparison, much lower prevalences were noted among female commercial sex workers (FCSWs; 0%-6.3%) and were associated mainly with a prior IDU and STI history. Env subtype B predominated among MSM throughout the region (more than 90% of strains), whereas env subtype F predominated among FCSWs in Argentina and male commercial sex workers in Uruguay (more than 50% of strains). A renewed effort in controlling STIs, especially among MSM groups, could significantly lessen the impact of the HIV epidemic in South America.
Asunto(s)
Infecciones por VIH/epidemiología , Infecciones por VIH/transmisión , VIH/genética , Adulto , Estudios Transversales , Transmisión de Enfermedad Infecciosa , Femenino , Productos del Gen env/genética , Análisis Heterodúplex , Homosexualidad Masculina , Humanos , Entrevistas como Asunto , Modelos Logísticos , Masculino , Epidemiología Molecular , Prevalencia , Factores de Riesgo , Trabajo Sexual , Conducta Sexual , América del Sur/epidemiología , Abuso de Sustancias por Vía IntravenosaRESUMEN
A cohort study involving 60 human immunodeficiency virus (HIV)-negative male transvestite commercial sex workers (CSWs) was conducted in Montevideo, Uruguay in 1999-2001. Serum samples were tested for HIV by an enzyme-linked immunosorbent assay screening with immunoblot confirmation. Six participants seroconverted for an incidence-density rate of 6.03 (95% confidence interval = 2.21-13.12) per 100 person-years. Inconsistent condom use during client sex (adjusted hazard ratio [AHR] = 6.7), during oral sex (AHR = 5.6), and at the last sexual encounter (AHR = 7.8), and use of marihuana (AHR = 5.4) were marginally associated with HIV seroconversion. Five samples were genotyped in the protease and reverse transcriptase regions; three were subtypes B and two were BF recombinants. Full genome analysis of four samples confirmed all three subtype B samples and one of the two BF recombinants. Male transvestite CSWs sustained a high rate of HIV infection. Larger prospective studies are required to better define subtypes and associated sexual and drug-related risk factors.
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Infecciones por VIH/epidemiología , VIH-1/clasificación , Filogenia , Trabajo Sexual , Adolescente , Adulto , Secuencia de Bases , Estudios de Cohortes , Cartilla de ADN , Ensayo de Inmunoadsorción Enzimática , Infecciones por VIH/virología , VIH-1/genética , Humanos , Incidencia , Factores de Riesgo , Uruguay/epidemiologíaRESUMEN
Serum specimens from patients at 4 sites in Peru were tested for evidence of spotted fever group rickettsial infection. Results showed that 30 (18%) of 170 patients had spotted fever group rickettsial infections, which likely caused their illnesses. These findings document laboratory-confirmed spotted fever from diverse areas of Peru.
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Infecciones por Rickettsia/epidemiología , Animales , Vectores Arácnidos , Humanos , Perú/epidemiología , GarrapatasRESUMEN
We conducted a randomized, double-blind, phase III yellow fever (YF) vaccine trial among 1,107 healthy children in Sullana in northern Peru. The safety and efficacy (by measurement of geometric mean neutralizing antibody titer responses) were determined for two YF vaccines, ARILVAX (n = 738) and YF-VAX(R) (n = 369). Serocon-version rates were higher (94.9%) in ARILVAX than in YF-VAX (90.6%) recipients. The two-sided 95% confidence interval (YF-VAX-ARILVAX) was (-12.8% to -2.5%), indicating that the higher seroconversion rate for Arilvax was significant. Post-vaccination (30-day) mean log(10) neutralization indices were found to be similar for both products: 1.32 for ARILVAX and 1.26 for YF-VAX (P = 0.1404, by analysis of variance). A similar number of subjects in each group reported at least one adverse event (AE); 441 (59.8%) for ARILVAX versus 211 (59.9%) for YF-VAX. Most (591; 96.7%) of these were of a mild nature and resolved without treatment. There were no treatment-related serious AEs. This is the first randomized, double-blind comparison of two YF vaccines in a pediatric population; both vaccines were shown to be highly immunogenic and well-tolerated.
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Vacuna contra la Fiebre Amarilla/uso terapéutico , Fiebre Amarilla/prevención & control , Virus de la Fiebre Amarilla/inmunología , Anticuerpos Antivirales/sangre , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Pruebas de Neutralización , Perú/epidemiología , Resultado del Tratamiento , Vacunación , Fiebre Amarilla/sangre , Fiebre Amarilla/epidemiología , Fiebre Amarilla/etiología , Fiebre Amarilla/inmunología , Vacuna contra la Fiebre Amarilla/efectos adversosRESUMEN
In August 2002, two cases of hantavirus pulmonary syndrome (HPS) were confirmed in Mineros and Concepcion, within the Santa Cruz Department of Bolivia. Extensive alteration of the native ecosystem, from dense forest to pasture or sugarcane, had occurred in both regions. An ecologic assessment of reservoir species associated with the human disease identified a single hantavirus antibody-positive Oligoryzomys microtis from Mineros and three hantavirus antibody-positive Calomys callosus from Concepcion. In Mineros, the virus from the O. microtis was 90% similar to sequences published for Rio Mamore virus. Viral nucleotide sequences from two C. callosus were 87-88% similar to the sequence of Laguna Negra virus. The viral sequence from the C. callosus was 99% identical to viral sequences obtained from the HPS patient in this area, implicating C. callosus as the host and Laguna Negra virus as the agent responsible for the HPS case near Concepcion.
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Síndrome Pulmonar por Hantavirus/epidemiología , Síndrome Pulmonar por Hantavirus/transmisión , Orthohantavirus/genética , Roedores/virología , Animales , Bolivia/epidemiología , Reservorios de Enfermedades , Genotipo , Orthohantavirus/clasificación , Orthohantavirus/aislamiento & purificación , Síndrome Pulmonar por Hantavirus/sangre , Humanos , Datos de Secuencia Molecular , Filogenia , ARN Viral/análisis , Ratas , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Phylogenetic analysis of five rickettsial genes (17-kDa gene, gltA, ompB, ompA, and sca4) from two molecular isolates of Candidatus Rickettsia andeanae from two ticks (Amblyomma maculatum and Ixodes boliviensis) collected from two domestic horses living in two separate locations in northern Peru (Coletas and Naranjo) was conducted to more clearly characterize this recently reported novel spotted fever group (SFG) rickettsia. Following nested polymerase chain reaction (PCR) amplification of the 17-kDa gene, gltA, ompB, ompA, and sca4, amplicons were purified, sequenced, and compared to those downloaded from GenBank. Phylogenetic analyses of the Candidatus Rickettsia andeanae sequences generated from 17-kDa gene (483 bp), gltA (1185 bp), ompA (1598 bp), ompB (4839 bp), and sca4 (2634 bp) demonstrated that they aligned strongly with those of SFG rickettsiae. Moreover, the sequences of these five genes most closely aligned with the following rickettsiae: ompA: Rickettsia sp RpA4 (98.03%), R. sp DnS28 (97.90%), and R. rhipicephali and R. massiliae (97.11%); ompB: R. aeschlimannii (97.22%), R. rhipicephali (97.20%), and R. sp Bar 29 (97.10%); and sca4: R. massiliae (97.8%), R. rhipicephali, and R. slovaca (97.7%). These results from the additional phylogenetic analyses of Candidatus Rickettsia andeanae confirm its inclusion within, and distance and uniqueness from, other known SFG rickettsiae.
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Filogenia , Rickettsia/genética , Rickettsia/aislamiento & purificación , Garrapatas/microbiología , Animales , Proteínas de la Membrana Bacteriana Externa/genética , Genes Bacterianos , Caballos/parasitología , Peso Molecular , Perú , Rickettsia/clasificaciónRESUMEN
Large-scale longitudinal cohort studies are necessary to characterize temporal and geographic variation in Aedes aegypti (L.) (Diptera: Culicidae) production patterns and to develop targeted dengue control strategies that will reduce disease. We carried out pupal/demographic surveys in a circuit of approximately 6,000 houses, 10 separate times, between January 1999 and August 2002 in the Amazonian city of Iquitos, Peru. We quantified the number of containers positive for Ae. aegypti larvae and/or pupae, containers holding pupae, and the absolute number of pupae by 4-mo sampling circuits and spatially by geographic area by using a geographic information system developed for the city. A total of 289,941 water-holding containers were characterized, of which 7.3% were positive for Ae. aegypti. Temporal and geographic variations were detected for all variables examined, and the relative importance of different container types for production of Ae. aegypti was calculated. Ae. aegypti larvae and pupae were detected in 64 types of containers. Consistent production patterns were observed for the lid status (lids: 32% wet containers, 2% pupal production), container location (outdoor: 43% wet containers, 85% pupal production), and method by which the container was filled with water (rain filled: 15% wet containers, 88.3% pupal production); these patterns were consistent temporally and geographically. We describe a new container category (nontraditional) that includes transient puddles, which were rare but capable of producing large numbers of pupae. Because of high variable pupal counts, four container categories (large tank, medium storage, miscellaneous, and nontraditional) should be targeted in addition to outdoor rain-filled containers that are not covered by a lid. The utility of targeted Ae. aegypti control is discussed, as well as the ability to achieve control objectives based on published but untested threshold values.
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Aedes/crecimiento & desarrollo , Animales , Demografía , Geografía , Humanos , Larva , Perú , Densidad de Población , Pupa , Factores de Tiempo , Salud UrbanaRESUMEN
Evidence of spotted fever group (SFG) rickettsiae was obtained from flea pools and individual ticks collected at three sites in northwestern Peru within the focus of an outbreak of febrile disease in humans attributed, in part, to SFG rickettsia infections. Molecular identification of the etiologic agents from these samples was determined after partial sequencing of the 17-kDa common antigen gene (htrA) as well as pairwise nucleotide sequence homology with one or more of the following genes: gltA, ompA, and ompB. Amplification and sequencing of portions of the htrA and ompA genes in pooled samples (2 of 59) taken from fleas identified the pathogen Rickettsia felis. Four tick samples yielded molecular evidence of SFG rickettsiae. Fragments of the ompA (540-bp) and ompB (2,484-bp) genes were amplified from a single Amblyomma maculatum tick (tick 124) and an Ixodes boliviensis tick (tick 163). The phylogenetic relationships between the rickettsiae in these samples and other rickettsiae were determined after comparison of their ompB sequences by the neighbor-joining method. The dendrograms generated showed that the isolates exhibited close homology (97%) to R. aeschlimannii and R. rhipicephali. Significant bootstrap values supported clustering adjacent to this nodule of the SFG rickettsiae. While the agents identified in the flea and tick samples have not been linked to human cases in the area, these results demonstrate for the first time that at least two SFG rickettsia agents were circulating in northern Peru at the time of the outbreak. Furthermore, molecular analysis of sequences derived from the two separate species of hard ticks identified a possibly novel member of the SFG rickettsiae.