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.

COVID-19 in Children: Correlation Between Epidemiologic, Clinical Characteristics, and RT-qPCR Cycle Threshold Values.

Background: Initially, the impact of SARS-CoV-2 infection on children was unknown. Standard COVID-19 diagnosis is confirmed using real-time qPCR. Cycle threshold (Ct) values of RT-qPCR are inversely proportional to viral load and the test indirectly quantifies viral RNA copy numbers.

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).

Respiratory syncytial virus in preterm infants: 19 years of active epidemiological surveillance in a children's hospital.

Introduction: Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infection (ALRTI) in pediatrics. Preterm infants are at a higher risk for complications. We aimed to describe and compare the clinical and epidemiological characteristics associated with ALRTI due to RSV in preterm and term infants and to establish the predictors of fatality among preterm infants.

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.

Pre-vaccine rotavirus surveillance in Buenos Aires, Argentina. Characterization of an emergent G1P[8] strain associated to fatal cases in 2014.

Group A rotaviruses (RVA) are the most frequent etiological agents causing severe diarrhea in infants and surveillance of genotype, and genetic characteristics of circulating strains are necessary in order to evaluate vaccine programs. The objectives of this work were to describe G and P genotype from 2012 through 2014 in Buenos Aires, Argentina completing an overview of 19 years of genotype surveillance in our region and to characterize an emerging G1P[8] strain associated with severe cases and five fatalities in 2014. We performed genotyping by RT-PCR.

Clinical and epidemiological impact of respiratory syncytial virus and identification of risk factors for severe disease in children hospitalized due to acute respiratory tract infection.

Introduction: Severe acute respiratory tract infection (ARTI) is a very common cause of hospitalization in pediatrics; respiratory syncytial virus (RSV) is the major etiologic agent. Accurately defining the burden of RSV life-threatening disease (LTD) and its risk factors is a challenge.

Objectives: To know the impact of RSV in children hospitalized due to ARTI and describe the risk factors for LTD.

Burden of Respiratory Syncytial Virus Disease and Mortality Risk Factors in Argentina: 18 Years of Active Surveillance in a Children's Hospital.

Background: Respiratory syncytial virus is the leading cause of acute lower respiratory infection in children. We aimed to describe the clinical-epidemiologic pattern and risk factors for mortality associated with RSV infection.

Methods: This is a prospective, cross-sectional study of acute lower respiratory infection in children admitted to the Children's Hospital during 2000 to 2017.

[Dengue outbreak in Buenos Aires, Argentina, 2016: Clinical and hematological features in children].

Unlabelled: Dengue is the human arbovirus with the highest morbidity and mortality in the world. The largest outbreak of dengue in Buenos Aires, Argentina, occurred during 2016.

Objective: To describe clinical and hematological features in children with confirmed dengue infection.

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.

[Acute disseminated encephalomyelitis due to Mycoplasma pneumoniae in a previously healthy boy].

We present here the case of a previously healthy 5 year-old boy hospitalized in an intensive care unit due to tonic-clonic seizures focused on the face and right side of the body, and axillary temperature of 37.4°C. Common bacterial and viral etiology was ruled out through studies of cerebrospinal fluid (CSF) samples.

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.

Influenza virus: 16 years' experience of clinical epidemiologic patterns and associated infection factors in hospitalized children in Argentina.

Background: Influenza is an important cause of acute lower respiratory tract infection (aLRTI), hospitalization, and mortality in children. This study aimed to describe the clinical and epidemiologic patterns and infection factors associated with influenza, and compare case features of influenza A and B.

Methods: In a prospective, cross-sectional study, patients admitted for aLRTI, between 2000 and 2015, were tested for respiratory syncytial virus, adenovirus, influenza, or parainfluenza, and confirmed by fluorescent antibody (FA) or real-time polymerase chain reaction (RT-PCR) assay of nasopharyngeal aspirates.

Bordetella pertussis (Bp) disease: Before (2003-2011) and after (2013-2016) maternal immunization strategy in a pediatric hospital.

Introduction: Whooping cough continues to be a major cause of morbidity and mortality in infants younger than 1 year. In 2012, Argentina introduced Tdap in pregnancy to prevent infant mortality. The aim of this study is to describe the impact of maternal immunization on the hospitalization and mortality rates of confirmed Bordetella pertussis (Bp) cases by comparing pre- and post-Tdap vaccine recommendation periods.