The Lambda Variant in Argentina: Analyzing the Evolution and Spread of SARS-CoV-2 Lineage C.37.

The second wave of COVID-19 occurred in South America in early 2021 and was mainly driven by Gamma and Lambda variants. In this study, we aimed to describe the emergence and local genomic diversity of the SARS-CoV-2 Lambda variant in Argentina, from its initial entry into the country until its detection ceased. Molecular surveillance was conducted on 9356 samples from Argentina between October 2020 and April 2022, and sequencing, phylogenetic, and phylogeographic analyses were performed.

Evolutionary dynamics of respiratory syncytial virus in Buenos Aires: Viral diversity, migration, and subgroup replacement.

Globally, the human respiratory syncytial virus (RSV) is one of the major causes of lower respiratory tract infections (LRTIs) in children. The scarcity of complete genome data limits our understanding of RSV spatiotemporal distribution, evolution, and viral variant emergence. Nasopharyngeal samples collected from hospitalized pediatric patients from Buenos Aires tested positive for RSV LRTI during four consecutive outbreaks (2014-2017) were randomly subsampled for RSV complete genome sequencing.

Assessing the hidden diversity underlying consensus sequences of SARS-CoV-2 using VICOS, a novel bioinformatic pipeline for identification of mixed viral populations.

Introduction: Coinfection with two SARS-CoV-2 viruses is still a very understudied phenomenon. Although next generation sequencing methods are very sensitive to detect heterogeneous viral populations in a sample, there is no standardized method for their characterization, so their clinical and epidemiological importance is unknown.

Material And Methods: We developed VICOS (Viral COinfection Surveillance), a new bioinformatic algorithm for variant calling, filtering and statistical analysis to identify samples suspected of being mixed SARS-CoV-2 populations from a large dataset in the framework of a community genomic surveillance.

Dengue beyond the tropics: a time-series study comprising 2015-2016 versus 2019-2020 at a children's hospital in the City of Buenos Aires.

Introduction: Dengue is a public health problem worldwide. It was originally confined to tropical and subtropical areas, but it is now present in other regions, such as Argentina. Epidemic outbreaks have been observed in the City of Buenos Aires since 2008, with few reports in children.

Agreement between diagnostic methods for SARS-CoV-2 infection in children seen at the Emergency Department of a children's hospital.

Introduction: Rapid antigen tests (RAgTs) for SARS-CoV-2 are considered adequate for diagnosis at the point of care. Our objective was to establish the agreement between reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and RAgTs in the pediatric population.

Population And Methods: All patients aged 1 month to 17 years and 11 months seen at the Emergency Fever Unit of a children's hospital between 6-11-2021 and 10-3-2021 were recruited.

Analysis of COL7A1 pathogenic variants in a large cohort of dystrophic epidermolysis bullosa patients from Argentina reveals a new genotype-phenotype correlation.

Dystrophic epidermolysis bullosa (DEB) is a clinically heterogeneous heritable skin disorder, characterized by blistering of the skin and mucous membranes following minor trauma. Dominant (DDEB) and recessive (RDEB) forms are caused by pathogenic variants in COL7A1 gene. Argentina's population has a heterogeneous genetic background, and little is known about the molecular basis of DEB in our country or in native South American populations.

Respiratory syncytial virus and influenza surveillance in schoolchildren seen at a children's hospital over 2 months of the second semester of 2021.

Introduction: Reporting of respiratory infections reduced during the COVID-19 pandemic. The objective was to estimate the prevalence of respiratory syncytial virus(RSV) and influenza in schoolchildren seen at a children's hospital during the return to school.

Methods: Cross-sectional study of patients aged 3-18 years suspected of COVID-19 with a negative test for SARS-CoV-2 between August and October 2021.

Impact of COVID-19 on the circulation of respiratory viruses in a children's hospital: an expected absence.

Introduction: Respiratory viruses are the main cause of acute lower respiratory tract infection (ALRTI) in the pediatric population. In March 2020, the World Health Organization declared that the new coronavirus disease 2019 (COVID-19) had reached the pandemic status. Our objective was to describe the impact of COVID-19 pandemic on hospitalizations due to ALRTI at Hospital de Niños Ricardo Gutiérrez (HNRG) and virus circulation.

RSV reemergence in Argentina since the SARS-CoV-2 pandemic.

Introduction: The community mitigation measures taken because of the COVID-19 pandemic had side effects on the circulation of the most frequent respiratory viruses during 2020. In the case of respiratory syncytial virus (RSV), an important paediatric pathogen, a decrease in the number of cases and delayed outbreaks was previously described.

Aim And Methods: The genetic characteristics of the RSV circulating strains in paediatric patients in Buenos Aires, Argentina before and during the COVID-19 pandemic were studied.

Cost-Effective Method to Perform SARS-CoV-2 Variant Surveillance: Detection of Alpha, Gamma, Lambda, Delta, Epsilon, and Zeta in Argentina.

SARS-CoV-2 variants with concerning characteristics have emerged since the end of 2020. Surveillance of SARS-CoV-2 variants was performed on a total of 4,851 samples from the capital city and 10 provinces of Argentina, during 51 epidemiological weeks (EWs) that covered the end of the first wave and the ongoing second wave of the COVID-19 pandemic in the country (EW 44/2020 to EW 41/2021). The surveillance strategy was mainly based on Sanger sequencing of a Spike coding region that allows the identification of signature mutations associated with variants.

Severe acute respiratory syndrome coronavirus 2019. Seroepidemiology study in Argentinian slum.

Most countries in Latin America have already reported thousands of confirmed cases and vulnerable populations are the most affected by the coronavirus disease 2019 (COVID-19) pandemic. Preventive measures such as hygiene, social distancing, and isolation, essential to stop the spread of coronavirus, are difficult to accomplish for vulnerable populations due to their living conditions. Seroepidemiological surveys are assets to measure the transmission for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Clinical and epidemiological study of acute lower respiratory tract infections caused by adenovirus in hospitalized children. Nineteen years of active epidemiological surveillance.

Introduction: Acute lower respiratory tract infection (ALRTI) caused by adenovirus is a major cause of morbidity and mortality in children.

Objectives: To describe the clinical and epidemiological pattern and associated factors in hospitalized children.

Methods: Cross-sectional study in children admitted due to ALRTI to Hospital de Niños "Ricardo Gutiérrez," in the Autonomous City of Buenos Aires, between 2000 and 2018.

Toward unified molecular surveillance of RSV: A proposal for genotype definition.

Background: Human respiratory syncytial virus (RSV) is classified into antigenic subgroups A and B. Thirteen genotypes have been defined for RSV-A and 20 for RSV-B, without any consensus on genotype definition.

Methods: We evaluated clustering of RSV sequences published in GenBank until February 2018 to define genotypes by using maximum likelihood and Bayesian phylogenetic analyses and average p-distances.

Acute Flaccid Myelitis Associated with Enterovirus D68 in Children, Argentina, 2016.

After a 2014 outbreak of severe respiratory illness caused by enterovirus D68 in the United States, sporadic cases of acute flaccid myelitis have been reported worldwide. We describe a cluster of acute flaccid myelitis cases in Argentina in 2016, adding data to the evidence of association between enterovirus D68 and this polio-like illness.

An optimized methodology for whole genome sequencing of RNA respiratory viruses from nasopharyngeal aspirates.

Over the last decade, the number of viral genome sequences deposited in available databases has grown exponentially. However, sequencing methodology vary widely and many published works have relied on viral enrichment by viral culture or nucleic acid amplification with specific primers rather than through unbiased techniques such as metagenomics. The genome of RNA viruses is highly variable and these enrichment methodologies may be difficult to achieve or may bias the results.

Dengue Virus 1 Outbreak in Buenos Aires, Argentina, 2016.

The largest outbreak of dengue in Buenos Aires, Argentina, occurred during 2016. Phylogenetic, phylodynamic, and phylogeographic analyses of 82 samples from dengue patients revealed co-circulation of 2 genotype V dengue virus lineages, suggesting that this virus has become endemic to the Buenos Aires metropolitan area.

Phylogenetic and molecular analyses of human parainfluenza type 3 virus in Buenos Aires, Argentina, between 2009 and 2013: The emergence of new genetic lineages.

Despite that human parainfluenza type 3 viruses (HPIV3) are one of the leading causes of acute lower respiratory tract infections in children under five, there is no licensed vaccine and there is limited current information on the molecular characteristics of regional and global circulating strains. The aim of this study was to describe the molecular characterization of HPIV3 circulating in Buenos Aires. We performed a genetic and phylogenetic analysis of the HN glycoprotein gene.

Dengue virus 1 in Buenos Aires from 1999 to 2010: towards local spread.

Dengue virus (DENV) is a public health problem representing the most important arthropod-borne viral disease in humans. In Argentina, Northern provinces have reported autochthonous cases since 1997, though these outbreaks have originated in bordering countries, where co-circulation of more than one serotype has been reported. In the last decade, imported dengue cases have been reported in Buenos Aires, the urban area of Argentina with the highest population density.

Respiratory syncytial virus: clinical and epidemiological pattern in pediatric patients admitted to a children's hospital between 2000 and 2013.

Introduction: Respiratory syncytial virus (RSV) is the major causative organism associated with acute lower respiratory tract infections in children.The objective of this study was to describe the clinical and epidemiological pattern of RSV and identify risk factors for RSV infection.

Population And Methods: Prospective, cohort study on patients hospitalized due to acute lower respiratory tract infection at Hospital de Niños Ricardo Gutiérrez between March and November throughout the 2000-2013 period.

Epidemiology of Bordetella pertussis in a children's hospital.

Introduction: Pertussis or whooping cough continues to be a major cause of morbidity and mortality in infants younger than 1 year old.

Objectives: To describe the clinical and epidemiological profile of Bordetella pertussis and to analyze the factors associated with confirmation by PCR and case fatality rate.

Material And Methods: Prospective, cohort study conducted between December 2003 and December 2011.

Phylogenetic and phylodynamic analyses of human metapneumovirus in Buenos Aires (Argentina) for a three-year period (2009-2011).

Human metapneumovirus, which belongs to the Paramyxoviridae family and has been classified as a member of the Pneumovirus genus, is genetically and clinically similar to other family members such as human respiratory syncytial virus. A total of 1146 nasopharyngeal aspirates from pediatric patients with moderate and severe acute lower respiratory tract infections, hospitalized at the Ricardo Gutierrez Childreńs Hospital (Buenos Aires, Argentina), were tested by real time RT-PCR for human metapneumovirus. Results showed that 168 (14.

Molecular evidence of St. Louis encephalitis virus infection in patients in Buenos Aires, Argentina.

We report two cases of St. Louis encephalitis where the virus was detected in patients' sera directly by molecular techniques allowing subsequent typing. Phylogenetic analysis of both samples showed that NS5 sequences clustered with viruses previously classified as genotype III.

Emergence of intratreatment resistance to oseltamivir in pandemic influenza A H1N1 2009 virus.

Background: Pandemic influenza A H1N1 2009 virus presents a new challenge to health authorities and communities worldwide. In Argentina, the outbreak was at its peak by the end of June 2009, during the southern winter. A systematic analysis of samples from patients with pandemic H1N1 2009 studied in our laboratory (Virology Laboratory, Hospital de Niños R Gutiérrez, Buenos Aires, Argentina) detected two patients presenting intratreatment emergence of the H275Y neuraminidase mutation, which confers resistance to oseltamivir.

Viruses and atypical bacteria associated with asthma exacerbations in hospitalized children.

Unlabelled: OBJECTIVES AND WORKING HYPOTHESIS: To evaluate the prevalence of respiratory viruses Mycoplasma pneumoniae and Chlamydophila pneumoniae and gain insight into their seasonal circulation pattern in children with acute asthma exacerbations in a temperate southern hemisphere region.

Study Design: Patients hospitalized between 3 months and 16 years of age were included in a 1-year prospective, observational, cross-sectional study. Respiratory secretions were collected and the presence of different viruses and atypical bacteria analyzed by immunofluorescence and polymerase chain reaction.