Browsing by Author "Vial, Pablo"
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- ItemA Single-Nucleotide Polymorphism of (V3) Integrin Is Associated with the Andes Virus Infection Susceptibility(2019) Martinez Valdebenito, Constanza Pamela; Angulo Troncoso Jenniffer Alexandra; Le Corre Pérez, Monique Nicole; Marco Caceres, Claudia Alejandra; Vial, Cecilia; Miquel Poblete, Juan Francisco; Cerda Lorca, Jaime Rodrigo; Mertz, Gregory; Vial, Pablo; Lopez Lastra, Marcelo Andres; Ferres Garrido, Marcela Viviana
- ItemAndes Virus Antigens Are Shed in Urine of Patients with Acute Hantavirus Cardiopulmonary Syndrome(AMER SOC MICROBIOLOGY, 2009) Godoy, Paula; Marsac, Delphine; Stefas, Elias; Ferrer, Pablo; Tischler, Nicole D.; Pino, Karla; Ramdohr, Pablo; Vial, Pablo; Valenzuela, Pablo D. T.; Ferres, Marcela; Veas, Francisco; Lopez Lastra, MarceloHantavirus cardiopulmonary syndrome (HCPS) is a highly pathogenic emerging disease (40% case fatality rate) caused by New World hantaviruses. Hantavirus infections are transmitted to humans mainly by inhalation of virus-contaminated aerosol particles of rodent excreta and secretions. At present, there are no antiviral drugs or immunotherapeutic agents available for the treatment of hantaviral infection, and the survival rates for infected patients hinge largely on early virus recognition and hospital admission and aggressive pulmonary and hemodynamic support. In this study, we show that Andes virus (ANDV) interacts with human apolipoprotein H (ApoH) and that ApoH-coated magnetic beads or ApoH-coated enzyme-linked immunosorbent assay plates can be used to capture and concentrate the virus from complex biological mixtures, such as serum and urine, allowing it to be detected by both immunological and molecular approaches. In addition, we report that ANDV-antigens and infectious virus are shed in urine of HCPS patients.
- ItemApOH-capture technology enhances Andes hantavirus detection allowing virus concentration from plasma and urine samples of patients with acute hantavirus cardiopulmonary syndrome(ELSEVIER SCIENCE BV, 2008) Godoy Mayorga, Paula Carolina; Stefas, Elias; Ferrer, Pablo; Vollrath, Valeska; Vial, Pablo; Ferres, Marcela; Veas, Francisco; Lopez Lastra, Marcelo
- ItemCase-Control Study of Risk Factors for Meningococcal Disease in Chile(2017) Olea, Andrea; Matute, Isabel; González, Claudia; Delgado, Iris; Poffald, Lucy; Pedroni, Elena; Alfaro, Tania; Hirmas, Macarena; Nájera, Manuel; Ferreccio Readi, Catterina; Gormaz, Ana; López, Darío; Loayza, Sergio; Gallegos, Doris; Fuentes, Rodrigo; Vial, Pablo; Aguilera, Ximena
- ItemHighly Differentiated, Resting Gn-Specific Memory CD8(+) T Cells Persist Years after Infection by Andes Hantavirus(PUBLIC LIBRARY SCIENCE, 2010) Manigold, Tobias; Mori, Andres; Graumann, Rebecca; Llop, Elena; Simon, Valeska; Ferres, Marcela; Valdivieso, Francisca; Castillo, Constanza; Hjelle, Brian; Vial, PabloIn man, infection with South American Andes virus (ANDV) causes hantavirus cardiopulmonary syndrome (HCPS). HCPS due to ANDV is endemic in Southern Chile and much of Argentina and increasing numbers of cases are reported all over South America. A case-fatality rate of about 36% together with the absence of successful antiviral therapies urge the development of a vaccine. Although T-cell responses were shown to be critically involved in immunity to hantaviruses in mouse models, no data are available on the magnitude, specificity and longevity of ANDV-specific memory T-cell responses in patients. Using sets of overlapping peptides in IFN-gamma ELISPOT assays, we herein show in 78 Chilean convalescent patients that Gn-derived epitopes were immunodominant as compared to those from the N- and Gc-proteins. Furthermore, while the relative contribution of the N-specific response significantly declined over time, Gn-specific responses remained readily detectable ex vivo up to 13 years after the acute infection. Tetramer analysis further showed that up to 16.8% of all circulating CD3(+)CD8(+) T cells were specific for the single HLA-B*3501-restricted epitope Gn(465-473) years after the acute infection. Remarkably, Gn(465-473)-specific cells readily secreted IFN-gamma, granzyme B and TNF-alpha but not IL-2 upon stimulation and showed a 'revertant' CD45RA(+)CD27(-)CD28(-)CCR7(-)CD127(-) effector memory phenotype, thereby resembling a phenotype seen in other latent virus infections. Most intriguingly, titers of neutralizing antibodies increased over time in 10/17 individuals months to years after the acute infection and independently of whether they were residents of endemic areas or not. Thus, our data suggest intrinsic, latent antigenic stimulation of Gn-specific T-cells. However, it remains a major task for future studies to proof this hypothesis by determination of viral antigen in convalescent patients. Furthermore, it remains to be seen whether Gn-specific T cells are critical for viral control and protective immunity. If so, Gn-derived immunodominant epitopes could be of high value for future ANDV vaccines.
- ItemModelo computacional interactivo, semi-automatizado y de código abierto aplicado a la vigilancia de virus respiratorios(Sociedad Chilena de Infectología, 2020) Reyes Zaldivar, Felipe Tomás; Ferrés, Marcela; Vial, Pablo; Vollrath Reyes, Valeska; Camponovo, Rossanna; Montecinos, Luisa; Hirsch Birn, Tamara; Valenzuela Contreras, Patricia; Perret Pérez, CeciliaLas infecciones respiratorias agudas (IRA) causadas por virus son una importante causa de morbilidad y mortalidad en el mundo, afectando principalmente a niños y adultos mayores. Se asocian a un alto número de consultas y hospitalizaciones, a una significativa sobrecarga del sistema de salud y a un alto costo económico. La vigilancia de virus respiratorios tiene el potencial de ayudar a optimizar la respuesta sanitaria, garantizar la disponibilidad de recursos humanos, racionalizar los recursos y disminuir los costos asociados a la atención en salud. Con el objetivo de optimizar la recolección y visualización de los datos de nuestro actual sistema de vigilancia de virus respiratorios, se diseñó una plataforma basada en R y sus paquetes Shiny, que permite la creación de una interfase web interactiva y amigable para la recolección, análisis y publicación de los datos. Se ingresaron a esta plataforma los datos de la red de vigilancia metropolitana de virus respiratorios disponibles desde 2006. En esta plataforma, el investigador demora menos de un minuto en registrar los datos. El análisis y publicación es inmediato, llegando a cualquier usuario con un dispositivo conectado a Internet, quien puede elegir las variables a consultar. Con un costo muy bajo, en poco tiempo y utilizando el lenguaje de programación R, se logró crear un sistema simple e interactivo, disminuyendo el tiempo de carga y análisis de datos de forma considerable, posiblemente aumentando el impacto y la disponibilidad de esta vigilancia.
- ItemOvercoming Health Inequities: Spatial Analysis of Seroprevalence and Vaccination Against COVID-19 in Chile(2024) Ramirez-Santana, Muriel; Correa, Juan; Franz, Loreto Nunez; Apablaza, Mauricio; Rubilar, Paola; Vial, Cecilia; Cortes, Lina Jimena; Hormazabal, Juan; Canales, Luis; Vial, Pablo; Aguilera, XimenaBackground: In unequal economies, the spread of the first waves of the COVID-19 was usually associated with low socioeconomic status of individuals and their families. Chile exemplified this. By mid-2020, Chile had one of the highest SARS-CoV-2 infection rates in the world predominantly in poorer areas. A year later, the country launched a universal vaccination campaign based on the national strategy of immunization established in 1975. By 2022, Chile presented one of the highest COVID-19 vaccination coverages globally, reaching 94.3% of the population with the primary scheme by the end of 2022.Objective: This study analyzes the spatial distribution of SARS-CoV-2 seroprevalence at the beginning of the pandemic (2020) compared with the seroprevalence after 2 years of ongoing epidemic and COVID-19 vaccination campaigns (2022).Methods: Two population-based random samples of individuals aged 7 years and older from two Chilean cities were studied. Utilizing an enzyme-linked immunosorbent assay test, IgG antibodies were measured in serum of 1061 participants in 2020, and 853 in 2022.Results: Using the Global Moran's Index, the seroprevalence distribution pattern for the year 2020 showed clustering in the two cities. Conversely, seroprevalence and vaccinations were homogeneously distributed in 2022. These results show the success of the vaccination campaign in Chile, not only in coverage but also because it widely reached all individuals.Conclusions: The uptake of this preventive measure is high, regardless of the social and economic factors, achieving broad population immunity. The extensive deployment of the primary health care network contributed to reducing health inequities and promoting to universal health access.
- ItemRange expansion of Oligoryzomys longicaudatus (Rodentia, Sigmodontinae) in Patagonian Chile, and first record of Hantavirus in the region(2009) Belmar-Lucero, Sebastian; Godoy, Paula; Ferres, Marcela; Vial, Pablo; Eduardo Palma, R.At present, 20 species of Oligoryzomys (Rodentia, Sigmodontinae) are recognized in the Neotropical region, most of them distinguished by their karyotypes, which fluctuates between 46-70 chromosomes. Two species are currently recognized in Chile, Oligoryzomys longicaudatus (Bennet, 1832: "colilargo" or the long-tailed pygmy rice rat: 2n = 56), which ranges from 27 degrees to approximately 51 degrees S, and O. magellanicus (Bennet, 1 836 Magellanic pygmy rice rate 2n = 54), south of 51 degrees S in the Patagonian region of Chile and Argentina. As part of an ongoing research on the southern Patagonia of Chile. we report the results Of small mammal samplings in six localities. We karyotyped 28 specimens and we also sequenced the hypervariable mtDNA region I in 22 individuals. aligning these sequences With an Under development phylogeny of O. longicaudatus. We also evaluated the serology and viral charge in all captured specimens to detect the presence of antibodies to Andes virus (ANDV) through Strip Immunoblot Assay (SIA), and of viral genome by RT-PCR. The results consistently showed that the karyotype of southern Patagonia specimens was 2n = 56, equal to that of O. longicaudatusand that individuals from this area (to not differentiate phylogenetically from those of the northern range of distribution. In addition, the serology showed the presence of antibodies IgG anti-ANDV and of viral genome in heart, kidney, spleen, and lungs S of a single specimen of Oligoryzomys from the locality of Fuerte Bulnes in the Magallanes region. We conclude that all specimens trapped south of 51 degrees S correspond to Oligoryzomys longicaudatus thus expanding the distribution of this speciei from 51 degrees to at least 55 degrees S. The results also extended the distribution of the Andes strain of Hantavirus to Southernmost Patagonia.
- ItemSingle nucleotide variant at the αvβ3 integrin associated to Andes virus infection susceptibility(2018) Martinez Valdebenito, Constanza Pamela; Angulo Troncoso, Jenniffer Alexandra; Le Corre Perez, Monique Nicole; Marco Caceres, Claudia Alejandra; Vial, Cecilia; Miquel Poblete, Juan Francisco; Cerda Lorca, Jaime Rodrigo; Mertz, Gregory; Vial, Pablo; Lopez Lastra, Marcelo Andres; Ferres Garrido Marcela Viviana
- ItemViral shedding and viraemia of Andes virus during acute hantavirus infection: a prospective study(2024) Ferres, Marcela; Martinez-Valdebenito, Constanza; Henriquez, Carolina; Marco, Claudia; Angulo, Jenniffer; Barrera, Aldo; Palma, Carlos; Pinto, Gonzalo Barriga; Cuiza, Analia; Ferreira, Leonila; Rioseco, Maria Luisa; Calvo, Mario; Fritz, Ricardo; Bravo, Sebastian; Bruhn, Alejandro; Graf, Jeronimo; Llancaqueo, Alvaro; Rivera, Gonzalo; Cerda, Carolina; Tischler, Nicole; Valdivieso, Francisca; Vial, Pablo; Mertz, Gregory; Vial, Cecilia; Le Corre, NicoleBackground Andes virus (ANDV) is a zoonotic Orthohantavirus leading to hantavirus cardiopulmonary syndrome. Although most transmissions occur through environmental exposure to rodent faeces and urine, rare person -toperson transmission has been documented, mainly for close contacts. This study investigates the presence and infectivity of ANDV in body fluids from confirmed cases and the duration of viraemia. Methods In this prospective study, 131 participants with confirmed ANDV infection were enrolled in Chile in a prospective study between 2008 and 2022. Clinical samples (buffy coat, plasma, gingival crevicular fluid [GCF], saliva, nasopharyngeal swabs [NPS], and urine) were collected weekly for 3 weeks together with clinical and epidemiological data. Samples were categorised as acute or convalescent (up to and after 16 days following onset of symptoms). Infectivity of positive fluids was assessed after the culture of samples on Vero E6 cells and use of flow cytometry assays to determine the production of ANDV nucleoprotein. Findings ANDV RNA was detected in 100% of buffy coats during acute phase, declining to 95% by day 17, and to 93% between days 23-29. ANDV RNA in GCF and saliva decreased from 30% and 12%, respectively, during the acute phase, to 12% and 11% during the convalescent phase. Successful infectivity assays of RT-qPCR-positive fluids, including GCF, saliva, NPS, and urine, were observed in 18 (42%) of 43 samples obtained during the acute phase of infection. After re -culture, the capacity to infect Vero E6 cells was maintained in 16 (89%) of 18 samples. Severity was associated with the presence of ANDV RNA in one or more fluids besides blood (odds ratio 258 [95% CI 142-518]). Interpretation ANDV infection is a systemic and viraemic infection, that affects various organs. The presence of infectious particles in body fluids contributes to our understanding of potential mechanisms for person -to -person transmission, supporting the development of preventive strategies. Detection of ANDV RNA in additional fluids at hospital admission is a predictor of disease severity. Funding National Institutes of Health and Agencia de Investigaci & oacute;n y Desarrollo. Copyright (c) 2024 Elsevier Ltd. All rights reserved.
- ItemYellow fever vaccination for Chilean tourists visiting Brazil. Practical considerations(SOC CHILENA INFECTOLOGIA, 2018) Weitzel, Thomas; Perret, Cecilia; Valdivieso, Francisca; Abarca, Katia; Vial, PabloDue to the recent yellow fever outbreak affecting the costal region of Brazil, including main touristic destinations, there is a high demand of yellow fever vaccination. This publication addresses the most relevant practical issues regarding this vaccine for tourists visiting Brazil and aims to serve as a guideline for non-expert physicians in Chile and elsewhere.