Browsing by Author "Martínez Valdebenito, Constanza"

Now showing 1 - 9 of 9
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    A rapid method for infectivity titration of Andes hantavirus using flow cytometry
    (2013) Barriga, Gonzalo P.; Martínez Valdebenito, Constanza; Galeno, Héctor; Ferrés Garrido, Marcela Viviana; Lozach, Pierre Yves; Tischler, Nicole D.
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    Geographical distribution and phylogenetic analysis of rhipicephalus sanguineus sensu lato in northern and central Chile
    (2018) Díaz Acevedo, Fabián Esteban; Martínez Valdebenito, Constanza; López, Javier; Weitzel, Thomas; Abarca Villaseca, Katia
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    Hosts and vectors of scrub typhus in Chile: epidemiological study and molecular analyses of Orientia infection in rodents and rodent-associated mites
    (2024) Martínez Valdebenito, Constanza; Acosta-Jamett, Gerardo; Abello, Rayitray; Jiang, Ju; Richards, Allen L.; Abarca Villaseca, Katia; Weitzel, Thomas
    Abstract Candidatus Orientia chiloensis causes scrub typhus over a wide geographical range in southern Chile. The life cycle, including vectors and reservoirs of this novel rickettsial pathogen, is incompletely understood. We analyzed rodent tissue and rodent-associated mite samples collected during a field study in six localities on Chiloé Island, where human scrub typhus cases have occurred. Using molecular methods, we detected Orientia DNA in 24.8% of rodents, belonging to five of seven captured species. Orientia-infection rates showed geographical variations, but were not influenced by rodent species, sex, age, and mite infestation. Phylogenetic analysis showed that Orientia sequences from trombiculid mites (Proschoengastia eloisae) were identical to those from scrub typhus patients from the same region. The results suggest that these rodent-associated mites serve as vectors and play an important role in the ecology of scrub typhus in southern Chile. Further studies are required to determine whether Orientia-infected rodents can also serve as reservoir of Orientia in Chile. Graphical Abstract
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    Human seroepidemiology of Rickettsia and Orientia species in Chile - A cross-sectional study in five regions
    (2020) Weitzel, T.; Acosta Jamett, G.; Jiang, J.; Martínez Valdebenito, Constanza; Farris, C. M.; Richards, A. L.; Abarca Villaseca, Katia
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    Humoral immune-response to a SARS-CoV-2- BNT162b2 booster in inflammatory arthritis patients who received an inactivated virus vaccine
    (BMJ PUBLISHING GROUP, 2022) Durán Santa Cruz, Josefina Gracia; Burgos Cañete, Paula Isabel; Le Corre Pérez, Monique Nicole; Ruiz-Tagle, Cinthya; Martínez Valdebenito, Constanza; Castro, Mauricio; Metcalfe Torres, Valentina Estrella; Niemann Concha, Paula Valentina; Balcells Marty, María Elvira
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    Insights into neutralizing antibody responses in individuals exposed to SARS-CoV-2 in Chile
    (2021) Beltrán Pavez, Carolina; Riquelme Barrios, Sebastián; Oyarzún Arrau, Aarón; Gaete Argel, Aracelly; González Stegmaier, Roxana; Cereceda Solis, Karina; Aguirre, Adam; Travisany, Dante; Palma Vejares, Ricardo; Barriga, Gonzalo P.; Gaggero, Aldo; Martínez Valdebenito, Constanza; Le Corre Pérez, Monique Nicole; Ferrés, Marcela; Balcells Marty, María Elvira; Fernández, Jorge; Ramírez, Eugenio; Villarroel, Franz; Valiente Echeverría, Fernando; Soto Rifo, Ricardo
    Chile has one of the worst numbers worldwide in terms of SARS-CoV-2 positive cases and COVID-19-related deaths per million inhabitants; thus, characterization of neutralizing antibody (NAb) responses in the general population is critical to understanding of immunity at the local level. Given our inability to perform massive classical neutralization assays due to the scarce availability of BSL-3 facilities in the country, we developed and fully characterized an HIV-based SARS-CoV-2 pseudotype, which was used in a 96-well plate format to investigate NAb responses in samples from individuals exposed to SARS-CoV-2 or treated with convalescent plasma. We also identified samples with decreased or enhanced neutralization activity against the D614G spike variant compared with the wild type, indicating the relevance of this variant in host immunity. The data presented here represent the first insights into NAb responses in individuals from Chile, serving as a guide for future studies in the country.
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    Mother-to-child transmission of Andes virus through breast milk, Chile
    (2020) Ferrés, Marcela; Martínez Valdebenito, Constanza; Angulo, J.; Henríquez, C.; Vera Otarola, Jorge Andrés; Vergara, M. J.; Vial Cox, María Cecilia; Vial Claro, Pablo; Pérez, J.; Le Corre Pérez, Monique Nicole; Fernández, J.; Sotomayor, V.; Valdés, M. F.; González-Candia, D.; Tischler, N. D.; Mertz, G.
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    SARS-CoV-2 vaccine booster in solid organ transplant recipients previously immunised with inactivated versus mRNA vaccines: A prospective cohort study
    (2022) Dib Marambio, Martín Javier; Le Corre Pérez, Monique Nicole; Ortiz Koh, Catalina Alejandra; García, Daniel; Ferrés, Marcela; Martínez Valdebenito, Constanza; Ruiz-Tagle, Cinthya; Ojeda Valenzuela, María José; Espinoza Sepúlveda, Manuel Antonio; Jara Contreras, Aquiles; Arab Verdugo, Juan Pablo; Rabagliati B., Ricardo; Vizcaya Altamirano, Cecilia; Ceballos, María Elena; Sarmiento Maldonado, Mauricio; Mondaca Contreras, Sebastián Patricio; Viñuela Morales, Macarena Rocío; Pastore Thomson, Antonia; Szwarcfiter Neiman, Vania; Galdames Lavín, Elizabeth Alejandra; Barrera Vásquez, Aldo Vincent; Castro Gálvez, Pablo Federico; Gálvez Arriagada, Nicolás Marcelo Salvador; Soto Ramírez, Jorge Andrés; Bueno Ramírez, Susan; Kalergis Parra, Alexis Mikes; Nervi Nattero, Bruno; Balcells Marty, María Elvira
    Solid-organ transplant (SOT) recipients have worse COVID-19 outcomes than general population and effective immunisation in these patients is essential but more difficult to reach. We aimed to determine the immunogenicity of an mRNA SARS-CoV-2 vaccine booster in SOT recipients previously immunised with either inactivated or homologous SARS-CoV-2 mRNA vaccine. Methods: Prospective cohort study of SOT recipients under medical care at Red de Salud UC-CHRISTUS, Chile, previously vaccinated with either CoronaVac or BNT162b2. All participants received a BNT162b2 vaccine booster. The primary study end point was anti-SARS-CoV-2 total IgG antibodies (TAb) seropositivity at 8-12 weeks (56-84 days) post booster. Secondary end points included neutralising antibodies (NAb) and specific T-cell responses. Findings: A total of 140 (50% kidney, 38% liver, 6% heart) SOT recipients (mean age 54 [13.6] years; 64 [46%] women) were included. Of them, 62 had homologous (three doses of BNT162b2) and 78 heterologous vaccine schedules (two doses of CoronaVac followed by BNT162b2 booster). Boosters were received at a median of 21.3 weeks after primary vaccination. The proportion achieving TAb seropositivity (82.3% vs 65.4%, P = 0.035) and NAb positivity (77.4% vs 55.1%, P = 0.007) were higher for the homologous versus the heterologous group. On the other hand, the number of IFN-γ and IL-2 secreting SARS-CoV-2-specific T-cells did not differ significantly between groups. Interpretation: This cohort study shows that homologous mRNA vaccine priming plus boosting in SOT recipients, reaches a significantly higher humoral immune response than inactivated SARS-CoV-2 vaccine priming followed by heterologous mRNA booster.
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    Serum levels of interleukin-6 are linked to the severity of the disease caused by Andes Virus
    (2017) Angulo, Jenniffer; Martínez Valdebenito, Constanza; Marco, Claudia; Galeno, Héctor; Villagra, Eliecer; Vera, Lilian; Lagos, Natalia; Becerra, Natalia; López Lastra, Marcelo Andrés; Ferrés Garrido, Marcela Viviana