VIAL COX, MARIA CECILIA
Thumbnail Image
Preferred name
VIAL COX, MARIA CECILIA
Main Affiliation
Email
mcvial@udd.cl
ORCID
Scopus Author ID
55553152400

Research Output

2024 2024 2023 2023 2022 2022 2021 2021 2020 2020 2019 2019 0.0 0.0 0.2 0.2 0.4 0.4 0.6 0.6 0.8 0.8 1.0 1.0 1.2 1.2 1.4 1.4 1.6 1.6 1.8 1.8 2.0 2.0

Filters

1
6
Reset filters

Settings
Now showing 1 - 6 of 6
No Thumbnail Available
Publication

SARS-CoV-2 infectivity and antigenic evasion: spotlight on isolated Omicron sub-lineages

2024 , Aldo Barrera , Constanza Martínez-Valdebenito , Jenniffer Angulo , Carlos Palma , HORMAZABAL CASTILLO, JUAN PATRICIO , VIAL COX, MARIA CECILIA , AGUILERA SANHUEZA, XIMENA PAZ , Pablo Castillo-Torres , Catalina Pardo-Roa , María Elvira Balcells , Bruno Nervi , Nicole Le Corre , Marcela Ferrés

Since the SARS-CoV-2 outbreak in 2019, a diversity of viral genomic variants has emerged and spread globally due to increased transmissibility, pathogenicity, and immune evasion. By the first trimester of 2023 in Chile, as in most countries, BQ and XBB were the predominant circulating sub-lineages of Omicron. The molecular and antigenic characteristics of these variants have been mainly determined using non-authentic spike pseudoviruses, which is often described as a limitation. Additionally, few comparative studies using isolates from recent Omicron sub-lineages have been conducted. In this study, we isolated SARS-CoV-2 variants from clinical samples, including the ancestral B.1.1, Delta, Omicron BA.1, and sub-lineages of BA.2 and BA.5. We assessed their infectivity through cell culture infections and their antibody evasion using neutralization assays. We observed variations in viral plaque size, cell morphology, and cytotoxicity upon infection in Vero E6-TMPRSS2 cells for each variant compared to the ancestral B.1.1 virus. BA.2-derived sub-variants, such as XBB.1.5, showed attenuated viral replication, while BA.5-derived variants, such as BQ.1.1, exhibited replication rates similar to the ancestral SARS-CoV-2 virus. Similar trends were observed in intestinal Caco-2 cells, except for Delta. Antibody neutralization experiments using sera from individuals infected during the first COVID-19 wave (FWI) showed a consistent but moderate reduction in neutralization against Omicron sub-lineages. Interestingly, despite being less prevalent, BQ.1.1 showed a 6.1-fold greater escape from neutralization than XBB.1.5. Neutralization patterns were similar when tested against sera from individuals vaccinated with 3xBNT162b2 (PPP) or Coronavac-Coronavac-BNT162b2 (CCP) schedules. However, CCP sera showed 2.3-fold higher neutralization against XBB.1.5 than FWI and PPP sera. This study provides new insights into the differences between BA.2 and BA.5-derived variants, leading to their eventual outcompetition. Our analysis offers important evidence regarding the balance between infectivity and antigenic escape that drives the evolution of second-generation SARS-CoV-2 variants in the population.

View
No Thumbnail Available
Publication

Viral shedding and viraemia of Andes virus during acute hantavirus infection: a prospective study

2024 , Marcela Ferrés , Constanza Martínez-Valdebenito , Carolina Henriquez , Claudia Marco , Jenniffer Angulo , Aldo Barrera , Carlos Palma , Gonzalo Barriga Pinto , Analia Cuiza , Leonila Ferreira , María Luisa Rioseco , Mario Calvo , Ricardo Fritz , Sebastián Bravo , Alejandro Bruhn , Jerónimo Graf , Alvaro Llancaqueo , Gonzalo Rivera , Carolina Cerda , Nicole Tischler , Francisca Valdivieso , VIAL CLARO, PABLO AGUSTIN , Gregory Mertz , VIAL COX, MARIA CECILIA , Nicole Le Corre

View
No Thumbnail Available
Publication

Novel Vector of Scrub Typhus in Sub-Antarctic Chile: Evidence From Human Exposure

2021 , WEITZEL, THOMAS , María Carolina Silva-de la Fuente , Constanza Martínez-Valdebenito , Alexandr A Stekolnikov , Caricia Pérez , Ruth Pérez , Katia Abarca , VIAL COX, MARIA CECILIA , Gerardo Acosta-Jamett

Abstract The exposure of a research team to chigger mites in southern Chile allowed the first identification of a trombiculid species as vector and reservoir of scrub typhus outside the tsutsugamushi triangle, providing unique insights into the ecology and transmission of this recently discovered rickettsial infection in South America.

View
No Thumbnail Available
Publication

A Single-Nucleotide Polymorphism of αVβ3 Integrin Is Associated with the Andes Virus Infection Susceptibility

2019 , Constanza Martínez-Valdebenito , Jenniffer Angulo , Nicole Le Corre , Claudia Marco , VIAL COX, MARIA CECILIA , Juan Miquel , Jaime Cerda , Gregory Mertz , VIAL CLARO, PABLO AGUSTIN , Marcelo Lopez-Lastra , Marcela Ferrés

The Andes Orthohantavirus (ANDV), which causes the hantavirus cardiopulmonary syndrome, enters cells via integrins, and a change from leucine to proline at residue 33 in the PSI domain (L33P), impairs ANDV recognition. We assessed the association between this human polymorphism and ANDV infection. We defined susceptible and protective genotypes as “TT” (coding leucine) and “CC” (coding proline), respectively. TT was present at a rate of 89.2% (66/74) among the first cohort of ANDV cases and at 60% (63/105) among exposed close-household contacts, who remained uninfected (p < 0.05). The protective genotype (CC) was absent in all 85 ANDV cases, in both cohorts, and was present at 11.4% of the exposed close-household contacts who remained uninfected. Logistic regression modeling for risk of infection had an OR of 6.2–12.6 (p < 0.05) in the presence of TT and well-known ANDV risk activities. Moreover, an OR of 7.3 was obtained when the TT condition was analyzed for two groups exposed to the same environmental risk. Host genetic background was found to have an important role in ANDV infection susceptibility, in the studied population.

View
No Thumbnail Available
Publication

Mother-to-Child Transmission of Andes Virus through Breast Milk, Chile1

2020 , Marcela Ferrés , Constanza Martínez-Valdebenito , Jenniffer Angulo , Carolina Henríquez , Jorge Vera-Otárola , María José Vergara , Javier Pérez , Jorge Fernández , Viviana Sotomayor , María Francisca Valdés , Diego González-Candia , Nicole D. Tischler , VIAL COX, MARIA CECILIA , VIAL CLARO, PABLO AGUSTIN , Gregory Mertz , Nicole Le Corre

View
No Thumbnail Available
Publication

Eco-epidemiology of rodent-associated trombiculid mites and infection with Orientia spp. in Southern Chile

2023 , María Carolina Silva de la Fuente , Caricia Pérez , Constanza Martínez-Valdebenito , Pérez Ball, Ruth , VIAL COX, MARIA CECILIA , Alexandr Stekolnikov , Katia Abarca , Gerardo Acosta-Jamett , WEITZEL, THOMAS , Jessica N. Ricaldi

Background Scrub typhus is a potentially severe infection caused by bacteria of the genus Orientia, endemic in Asia-Pacific and recently discovered in southern Chile. The presented study aimed to determine the prevalence and species richness of rodent-associated trombiculid mites and their infection with Orientia spp. in different areas of two regions in southern Chile. Methodology/Principal findings During summer 2020, trombiculid mites were collected from rodents captured in three areas in southern Chile known to be endemic for scrub typhus (Cochamó and Chiloé Island in the Los Lagos Region and Tortel in the Aysén Region). A total of 132 rodents belonging to five species were captured using Sherman-like traps; 89.4% were infested with trombiculids. Mite specimens were morphologically identified and subsequently tested by Orientia-specific qPCR. Six mite species were identified. Among chigger-infested rodents, 33.9% carried Orientia-positive mites; this rate was higher in Tortel (63.8%) than in Cochamó (45.0%) and Chiloé Island (2.0%). The analysis of individual mites (n = 901) revealed that 31.2% of Herpetacarus antarctica samples (n = 202) were positive for Orientia DNA; the prevalence was 7.0% in Paratrombicula neuquenensis (n = 213), 6.9% in Herpetacarus eloisae (n = 144), 3.6% in Argentinacarus expansus (n = 55), and 0% in Paratrombicula goffi (n = 110) and Quadraseta chiloensis (n = 177). The southernmost site (Tortel) showed the highest rates of trombiculid infestation, trombiculid load, and Orientia infection in the captured rodents. Conclusions/Significance Our study provides new insights into the trombiculid fauna and prevalence of Orientia in mites collected from wild rodents in southern Chile. Orientia DNA was detected in four of the six mite species. Rates of infestation, mite loads, and Orientia prevalences differed geographically and were highest in the Aysén Region. Our data improve our knowledge on possible vectors of scrub typhus and their distribution in Chile.

View