Browsing by Author "Pardo-Roa, Catalina"

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    First report and genetic characterization of Seneca Valley virus (SVV) in Chile
    (SPRINGER INTERNATIONAL PUBLISHING AG, 2022) Bennett, Benjamin; Urzua-Encina, Constanza; Pardo-Roa, Catalina; Ariyama, Naomi; Lecocq, Claudio; Rivera, Carlos; Badia, Catalina; Suarez, Paulina; Agredo, Michel; Aguayo, Carolina; Avila, Claudia; Araya, Hugo; Perez, Patricio; Berrios, Felipe; Aguero, Belen; Mendieta, Vanessa; Pituco, Edviges Maristela; de Almeida, Iassudara Garcia; Medina, Rafael; Brito, Barbara; Johow, Magdalena; Neira Ramirez, Victor
    Seneca Valley virus (SVV) is a non-enveloped RNA virus and the only member of the Senecavirus A (SVA) species, in the Senecavirus genus, Picornaviridae family. SVV infection causes vesicular lesions in the oral cavity, snout and hooves of pigs. This infection is clinically indistinguishable from trade-restrictions-related diseases such as foot-and-mouth disease. Other clinical manifestations include diarrhoea, anorexia, lethargy, neurological signs and mortality in piglets during their first week of age. Before this study, Chile was considered free of vesicular diseases of swine, including SVV. In April 2022, a suspected case of vesicular disease in a swine farm was reported in Chile. The SVV was confirmed and other vesicular diseases were ruled out. An epidemiological investigation and phylogenetic analyses were performed to identify the origin and extent of the outbreak. Three hundred ninety-five samples from 44 swine farms were collected, including faeces (208), oral fluid (28), processing fluid (14), fresh semen (61), environmental samples (80) and tissue from lesions (4) for real-time RT-PCR detection. Until June 2022, the SVV has been detected in 16 out of 44 farms, all epidemiologically related to the index farm. The closest phylogenetic relationship of the Chilean SVV strain is with viruses collected from swine in California in 2017. The direct cause of the SVV introduction has not yet been identified; however, the phylogenetic analyses suggest the USA as the most likely source. Since the virus remains active in the environment, transmission by fomites such as contaminated feed cannot be discarded. Further studies are needed to determine the risk of the introduction of novel SVV and other transboundary swine pathogens to Chile.
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    Limited Heme Oxygenase Contribution to Modulating the Severity of Salmonella enterica serovar Typhimurium Infection
    (SPRINGER INTERNATIONAL PUBLISHING AG, 2022) Sebastian, Valentina P.; Moreno-Tapia, Daniela; Melo-Gonzalez, Felipe; Hernandez-Caceres, Maria P.; Salazar, Geraldyne A.; Pardo-Roa, Catalina; Farias, Monica A.; Vallejos, Omar P.; Schultz, Barbara M.; Morselli, Eugenia; Alvarez-Lobos, Manuel M.; Gonzalez, Pablo A.; Kalergis, Alexis M.; Bueno, Susan M.
    An important virulence trait of Salmonella enterica serovar Typhimurium (S. Typhimurium) is the ability to avoid the host immune response, generating systemic and persistent infections. Host cells play a crucial role in bacterial clearance by expressing the enzyme heme oxygenase 1 (Hmox1), which catalyzes the degradation of heme groups into Fe2+, biliverdin, and carbon monoxide (CO). The role of Hmox1 activity during S. Typhimurium infection is not clear and previous studies have shown contradictory results. We evaluated the effect of pharmacologic modulation of Hmox1 in a mouse model of acute and persistent S. Typhimurium infection by administering the Hmox1 activity inductor cobalt protoporphyrin-IX (CoPP) or inhibitor tin protoporphyrin-IX (SnPP) before infection. To evaluate the molecular mechanism involved, we measured the colocalization of S. Typhimurium and autophagosome and lysosomal markers in macrophages. Administering CoPP reduced the bacterial burden in organs of mice 5 days post-infection, while SnPP-treated mice showed bacterial loads similar to vehicle-treated mice. Furthermore, CoPP reduced bacterial loads when administered after infection in macrophages in vitro and in a persistent infection model of S. Typhimurium in vivo, while tin protoporphyrin-IX (SnPP) treatment resulted in a bacterial burden similar to vehicle-treated controls. However, we did not observe significant differences in co-localization of green fluorescent protein (GFP)-labeled S. Typhimurium with the autophagic vesicles marker microtubule-associated protein 1A/1B-light chain 3 (LC3) and the lysosomal marker lysosomal-associated membrane protein 1 (LAMP-1) in macrophages treated with CoPP. Our results suggest that CoPP can enhance antimicrobial activity in response to Salmonella infection, reducing bacterial dissemination and persistence in mice, in a CO and autophagy- independent manner.
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    Viral shedding dynamics reveals sputum as a reliable and cost-saving specimen for SARS-CoV-2 diagnosis within the first 10 days since symptom onset: A prospective cohort study
    (2020) Levican, Jorge; Almonacid, Leonardo I.; Valenzuela, Gonzalo; García-Salum, Tamara; Rojas, Luis; Serrano, Eileen; Pardo-Roa, Catalina; Salinas, Erick; Avendaño, María José; Perazzo, Fabiola; Díaz, Luis Antonio; Valderrama, Sebastián; Ortega, Marcos; Toro, Adriana; Montecinos, Viviana; Riquelme, Arnoldo; Medina, Rafael A.
    Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome virus (SARS-CoV-2) is challenging global public health, due to an increasing demand for testing and the shortage of diagnostic supplies. Nasopharyngeal swab (NPS) is considered the optimal sample for SARS-CoV2 diagnosis and sputum (SPT) has been proposed as an economic alternative. However, the temporal concordance of diagnosis in NPS and SPT has not been addressed. Methods: Through a longitudinal study we compared the shedding dynamics of SARS-CoV-2 RNA evaluated by RT-qPCR in serially collected SPT and NPS obtained from 82 ambulatory and hospitalized patients during acute infection and convalescence. The concordance during the follow-up and cost analysis between both collected specimens was evaluated. Findings: We analyzed 379 samples, 177 NPS and 202 SPT. The highest proportion of positive samples was detected within the first 15 days after the symptoms onset. The median time of positivity was higher for NPS (median= 25 days) than SPT (median= 21 days). There was no significant difference in the median RT-qPCR CT values between both sample types. The temporal categorization of matched-paired samples indicated substantial correlation (r=0·6023) and substantial agreement (87·23%) during the first ten days since symptoms onset (kappa = 0·697). A cost analysis demonstrated a significant saving when the SPT specimen was used. Interpretation: Sputum is a feasible and cost-saving alternative to NPS, providing an equivalent value for the detection and follow-up of SARS-CoV-2 RNA.