Browsing by Author "Abarca Villaseca, Katia"

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    A phase 2, randomized double-blind safety and pharmacokinetic assessment of respiratory syncytial virus (RSV) prophylaxis with motavizumab and palivizumab administered in the same season
    (2010) Fernández, P.; Trenholme, A.; Abarca Villaseca, Katia; Griffin, M. P.; Hultquist, M.; Harris, B.; Losonsky, G. A.
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    Aberrant T cell immunity triggered by human Respiratory Syncytial Virus and human Metapneumovirus infection
    (2017) González, A. E.; Lay, M. K.; Jara, E. L.; Espinoza, J. A.; Gómez, R. S.; Soto, J.; Rivera, C. A.; Abarca Villaseca, Katia; Bueno Ramírez, Susan; Riedel, C. A.; Kalergis Parra, Alexis Mikes
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    Absence of convincing evidence of Coxiella burnetii infection in Chile: a cross-sectional serosurvey among healthy adults in four different regions
    (2016) Weitzel, Thomas; López, Javier; Acosta-Jamett, Gerardo; Edouard, Sophie; Parola, Philippe; Abarca Villaseca, Katia
    Abstract Background Coxiella burnetii is an important zoonotic pathogen of global distribution. Still, in most parts of South America including Chile, systematic epidemiological data are lacking. The presented study aims to determine the seroprevalence of Coxiella burnetii antibodies in healthy adults of four different regions in Chile. Methods A cross-sectional study was performed, which included healthy adults living in rural and urban areas of four cities located in different regions in northern, central, and southern Chile. In urban sectors, households were chosen by double stratified random sampling, while in rural areas convenience sampling was performed. Serum specimens were taken and screened for the presence of IgG antibodies against C. burnetii phase II antigen using a commercial ELISA kit. Positive and indeterminate results were confirmed by a reference laboratory using indirect immunofluorescence assay (IFA). Results A total of 1112 individuals were included. Of those, 8 were positive by ELISA, but only one sample was confirmed using IFA. Statistical analysis for population freedom from disease revealed a high probability that C. burnetii was absent in our study population. Conclusion Our work provides the first epidemiological data on human Q fever in Chile indicating either a very low endemicity or the absence of this pathogen in the studied areas.Abstract Background Coxiella burnetii is an important zoonotic pathogen of global distribution. Still, in most parts of South America including Chile, systematic epidemiological data are lacking. The presented study aims to determine the seroprevalence of Coxiella burnetii antibodies in healthy adults of four different regions in Chile. Methods A cross-sectional study was performed, which included healthy adults living in rural and urban areas of four cities located in different regions in northern, central, and southern Chile. In urban sectors, households were chosen by double stratified random sampling, while in rural areas convenience sampling was performed. Serum specimens were taken and screened for the presence of IgG antibodies against C. burnetii phase II antigen using a commercial ELISA kit. Positive and indeterminate results were confirmed by a reference laboratory using indirect immunofluorescence assay (IFA). Results A total of 1112 individuals were included. Of those, 8 were positive by ELISA, but only one sample was confirmed using IFA. Statistical analysis for population freedom from disease revealed a high probability that C. burnetii was absent in our study population. Conclusion Our work provides the first epidemiological data on human Q fever in Chile indicating either a very low endemicity or the absence of this pathogen in the studied areas.Abstract Background Coxiella burnetii is an important zoonotic pathogen of global distribution. Still, in most parts of South America including Chile, systematic epidemiological data are lacking. The presented study aims to determine the seroprevalence of Coxiella burnetii antibodies in healthy adults of four different regions in Chile. Methods A cross-sectional study was performed, which included healthy adults living in rural and urban areas of four cities located in different regions in northern, central, and southern Chile. In urban sectors, households were chosen by double stratified random sampling, while in rural areas convenience sampling was performed. Serum specimens were taken and screened for the presence of IgG antibodies against C. burnetii phase II antigen using a commercial ELISA kit. Positive and indeterminate results were confirmed by a reference laboratory using indirect immunofluorescence assay (IFA). Results A total of 1112 individuals were included. Of those, 8 were positive by ELISA, but only one sample was confirmed using IFA. Statistical analysis for population freedom from disease revealed a high probability that C. burnetii was absent in our study population. Conclusion Our work provides the first epidemiological data on human Q fever in Chile indicating either a very low endemicity or the absence of this pathogen in the studied areas.
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    An Update on Host-Pathogen Interplay and Modulation of Immune Responses during Orientia tsutsugamushi Infection
    (2018) Díaz Acevedo, Fabián Esteban; Abarca Villaseca, Katia; Kalergis Parra, Alexis Mikes
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    Canine seroprevalence to Orientia species in southern Chile: A cross-sectional survey on the Chiloe A Island
    (2018) Weitzel, Thomas; Jiang, Ju; Acosta-Jamett, Gerardo; Martinez-Valdebenito, Constanza; Lopez, Javier; Richards, Allen L.; Abarca Villaseca, Katia
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    Concordancia del hisopado nasal con el hisopado nasofaríngeo en la detección de virus respiratorios por inmunofluorescencia directa
    (2014) Del Pozo Bascuñan, Paulina Andrea; Abarca Villaseca, Katia; Concha Murray, Ida; Cerda, Jaime
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    Descripción clínica y epidemiológica de la infección por Clostridium difficile en población pediátrica
    (2015) Maccioni, Andrea; Cerda, Jaime; Terrazas, Claudia; Abarca Villaseca, Katia
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    Detección del SARS-CoV-2 mediante RT-qPCR utilizando saliva en pacientesambulatorios con estudio de COVID-19
    (2022) Perret Perez, Cecilia; Abarca Villaseca, Katia; Solari Gajardo, Sandra; Aguilera, Pablo; Garcia-huidobro Munita, Diego Nicolas; Olivares, Felipe; Palma, Carlos; Contreras, Ana María; Martinez Valdebenito, Constanza Pamela; Ferrés, Marcela
    La pandemia de COVID-19 ha afectado a millonesde personas en todo el mundo. La identificación de sujetos infectadosha sido importante para el control. Objetivo: Evaluar el rendimiento deuna reacción de polimerasa en cadena (RPC) cuantitativa en tiemporeal (en inglés: RT-qPCR) para SARS-CoV-2, utilizando saliva comomatriz en comparación con un hisopado nasofaríngeo (HNF). Metodología: Se reclutaron adultos en atención ambulatoria, la mayoría sintomáticos. Fueron estudiadas 530 muestras pareadas de saliva e HNF con RT-qPCR. Resultados: Fueron positivas 59 muestras de HNF y 54 de saliva. La sensibilidad con saliva fue 91%, especificidad 100%, el valor predictor positivo (VPP) 100%, valor predictor negativo (VPN) 98%. El índice Kappa fue de 0,95 y LR-0,08. En promedio, el umbral de ciclo (en inglés cycle threshold-CT) de la saliva fue 3,99 puntos más alto que los de HNF (p < 0,0001) mostrando que la carga viral (CV) es menor en saliva. La carga viral en ambas disminuyó con el tiempo después del inicio de los síntomas. El muestreo de saliva fue preferido por los sujetos en lugar de HNF. Conclusión: Este estudio demuestra que la RPC para SARS-CoV-2 utilizando saliva, es adecuada para el diagnóstico de COVID-19 en adultos ambulatorios,especialmente en la etapa temprana de los síntomas.
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    Different Safety Pattern of an Inactivated SARS-CoV-2 Vaccine (CoronaVac®) According to Age Group in a Pediatric Population from 3 to 17 Years Old, in an Open-Label Study in Chile
    (2023) Le Corre, Nicole; Abarca Villaseca, Katia; Astudillo, Patricio André; Potin Santander, Marcela Patricia; López, Sofía; Goldsack, Macarena; Valenzuela Guerrero, Vania; Schilling Redlich, Andrea; Gaete, Victoria; Rubio, Lilian; Calvo, Mario; Twele, Loreto; González, Marcela; Fuentes, Daniela; Gutiérrez Muñoz, Valentina José; Reyes Zaldivar, Felipe Tomás; Tapia, Lorena I.; Villena, Rodolfo; Retamal Díaz, Angello; Cárdenas, Antonio; Alarcón Bustamante, Eduardo; Xin, Qianqian; González Aramundiz, José Vicente; Álvarez Figueroa, María Javiera; González Muñoz, Pablo Alberto; Bueno Ramírez, Susan; Soto Ramírez, Jorge Andrés; Perret Pérez, Cecilia; Meng, Xing; Kalergis Parra, Alexis Mikes
    During the COVID-19 pandemic, the importance of vaccinating children against SARS-CoV-2 was rapidly established. This study describes the safety of CoronaVac® in children and adolescents between 3- and 17-years-old in a multicenter study in Chile with two vaccine doses in a 4-week interval. For all participants, immediate adverse events (AEs), serious AEs (SAEs), and AEs of special interest (AESIs) were registered throughout the study. In the safety subgroup, AEs were recorded 28 days after each dose. COVID-19 surveillance was performed throughout the study. A total of 1139 individuals received the first and 1102 the second dose of CoronaVac®; 835 were in the safety subgroup. The first dose showed the highest number of AEs: up to 22.2% of participants reported any local and 17.1% systemic AE. AEs were more frequent in adolescents after the first dose, were transient, and mainly mild. Pain at the inoculation site was the most frequent AE for all ages. Fever was the most frequent systemic AE for 3–5 years old and headache in 6–17 years old. No SAEs or AESIs related to vaccination occurred. Most of the COVID-19 cases were mild and managed as outpatients. CoronaVac® was safe and well tolerated in children and adolescents, with different safety patterns according to age.
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    Disruption of an antimycobacterial circuit between dendritic and helper T cells in human SPPL2a deficiency
    (2018) Kong, Xiao-Fei; Martínez Barricarte, Rubén; Kennedy, James; Mele, Federico; Lazarov, Tomi; Deenick, Elissa K.; Ma, Cindy S.; Breton, Gaëlle; Lucero, Kimberly B.; Abarca Villaseca, Katia
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    Endemic Scrub Typhus in South America
    (2016) Weitzel, T.; Dittrich, S.; López, J.; Phuklia, W.; Martínez, Constanza; Velásquez, K.; Blacksell, S.; Paris, D.; Abarca Villaseca, Katia
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    Endemic Scrub Typhus-like Illness, Chile
    (Centers for Disease Control an Prevention, 2011) Balcells Marty, María Elvira; Rabagliati Borie, Ricardo Miguel; García Cañete, Patricia Del Carmen; Poggi Mayorga, Helena Loreto; Oddo Benavides, Carlos David; Concha Rogazy, Marcela Andrea; Abarca Villaseca, Katia; Jiang, Ju; Kelly, Daryl J.; Richards, Allen L.; Fuerst, Paul A.
    We report a case of scrub typhus in a 54-year-old man who was bitten by several terrestrial leeches during a trip to Chiloe Island in southern Chile in 2006. A molecular sample, identified as related to Orientia tsutsugamushi based on the sequence of the 16S rRNA gene, was obtained from a biopsy specimen of the eschar on the patient's leg. Serologic analysis showed immunoglobulin G conversion against O. tsutsugamushi whole cell antigen. This case and its associated molecular analyses suggest that an Orientia-like agent is present in the Western Hemisphere that can produce scrub typhus-like illness. The molecular analysis suggests that the infectious agent is closely related, although not identical, to members of the Orientia sp. from Asia.
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    Evaluation of a new syringe presentation of reduced-antigen content diphtheria, tetanus, and acellular pertussis vaccine in healthy adolescents - A single blind randomized trial
    (2015) Pavia Ruz, Noris; Abarca Villaseca, Katia; Lepetic, Alejandro; Cervantes Apolinar, María Yolanda; Hardt, Karin; Jayadeva, Girish; Kuriyakose, Sherine; Han, Htay Htay; De La O, Manuel
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    Evidencia seroepidemiológica de exposición humana a Anaplasma sp en Santiago, Chile
    (2008) Abarca Villaseca, Katia; López del P., Javier; González A.,Patricia; Dabanch P., Jeannette; Torres Hidalgo, Marisa; Solari G., Verónica; Perret Pérez, Cecilia
    Objetivos y Método: Con el propósito de buscar mayor evidencia de exposición humana a Anaplasma sp en Chile, se estudiaron 108 personas en contacto con perros con ehrlichiosis canina (EC) (grupo de riesgo) y 61 personas sin antecedente de contacto con garrapatas ni con perros con EC (grupo control). Se aplicó encuesta sobre factores de riesgo e historia de cuadros sugerentes de ehrlichiosis/anaplasmosis al grupo de riesgo. En ambos grupos se determinó presencia de IgG anti-Anaplasma sp. Resultados: Se encontró significativa mayor prevalencia de anticuerpos anti-Anaplasma sp en el grupo de riesgo que en el grupo control (18,5 versus 3,3%), p < 0,005. No se encontraron factores de riesgo asociados a sero-positividad, ni personas con historia sugerente de ehrlichiosis/anaplasmosis clínica. Noventa y cuatro por ciento de las viviendas del grupo de riesgo presentaba infestación por garrapatas. Discusión: Se evidencia mayor riesgo de exposición humana a Anaplasma sp en personas en contacto cercano con perros con EC y que habitan viviendas con infestación por garrapatas.
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    Exactitud y utilidad diagnóstica de la IgM en infecciones por Bartonella henselae
    (2013) Abarca Villaseca, Katia; Winter, Matías; Marsac, Delphine; Palma, Carlos; Contreras, Ana M.; Ferrés Garrido, Marcela Viviana
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    Exome Sequencing Reveals Primary Immunodeficiencies in Children with Community-Acquired Pseudomonas aeruginosa Sepsis
    (2016) Asgari, S.; Mclaren, P. J.; Peake, J.; Wong, M.; Wong, R.; Bartha, I.; Francis, J. R.; Abarca Villaseca, Katia; Gelderman, K. A.; Agyeman, P.; Aebi, C.; Berger Silva, Christian; Fellay, J.; Schlapbach, L. J.
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    Fiebre amarilla
    (2001) Abarca Villaseca, Katia; Dabanch, P., Jeannette; González, C., Cecilia; Maggi, C., Leonardo; Olivares, C., Roberta; Perret Perez, Cecilia; Rodríguez Troncoso, Jaime Patricio; Vergara, F., Rodrigo
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    Flea and ticks species from dogs in urban and rural areas in four districts in Chile
    (2016) Abarca Villaseca, Katia; Garate, D.; Lopez, J.; Acosta, G.