Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections in young children. During the COVID-19 pandemic, a significant change in the epidemiology of RSV and other viruses occurred worldwide, leading to a reduction in the circulation of these infectious agents. After the pandemic, the resurgence of seasonal respiratory viruses occurred, but some features of these infections contrast to those registered prior to the pandemic. In the present work, we studied 390 children <5 years old admitted to the hospital to determine the contribution of RSV, SARS-CoV-2, human metapneumovirus (hMPV), and influenza viruses to acute respiratory infections during the 2023–2024 winter season in Mexico. RSV was the most frequently detected virus (n = 160, 41%), followed by SARS-CoV-2 (n = 69, 17.7%), hMPV (n = 68, 17.4%), and influenza A or B (n = 40, 10.26%). Fourteen patients required admission to the intensive care unit, including six (42.8%) with RSV infection. Four children died (1%). At least one of the four viruses was detected in all deceased patients: SARS-CoV-2 in one; SARS-CoV-2 and hMPV in two; and RSV, influenza A, and SARS-CoV-2 in one. The high impact of RSV and other respiratory viruses indicates the need to implement specific preventive programs to reduce the morbidity and mortality associated with them.

In recent years, wastewater (WW)-based epidemiology has been increasingly used for surveillance of SARS-CoV-2 and has emerged as a potential tool for monitoring other respiratory viruses. Most evidence on the use of WW for detecting multiple respiratory viruses comes from developed countries. In this study, we assessed the feasibility of multi-respiratory virus sewage surveillance in a middle-income country and explored signals that may be potentially used as early warning signs for Public Health authorities. We examined the presence of SARS-CoV-2, influenza virus, respiratory syncytial virus (RSV), and human metapneumovirus (hMPV) in 238 WW samples collected from three treatment plants in San Luis Potosí, Mexico, over one year. The weekly detection of each virus was compared with the weekly number of hospital admissions for respiratory infections caused by that virus in pediatric patients. SARS-CoV-2, influenza, hMPV, and RSV were detected in 152 (63.9%), 108 (45.4%), 95 (39.9%), and 24 (10.1%) samples, respectively. There was no significant correlation between viral detection in WW and the number of hospitalizations during that week. However, analyses of WW viral detection with hospitalizations in subsequent weeks showed an increasing correlation reaching a maximum correlation for a lag of 12 weeks for SARS-CoV-2 (r_s = 0.63, p = 0.001), 9 weeks for influenza (r_s 0.62, p = 0.0001), 2 weeks for RSV (r_s = 0.30, p = 0.05), and 3 weeks for hMPV (r_s = 0.39, p = 0.009). In addition, we identified time-periods of SARS-CoV-2, influenza, and RSV widespread circulation (several consecutive weeks in which viruses were detected in the three treatment plants); most hospitalizations caused by these viruses occurred after widespread circulation was detected in WW, suggesting this may be used as an early alert for public health systems. Overall, our results show that WW-based surveillance of multiple respiratory viruses is feasible and has potential applications as an early warning system in middle-income countries.

Infections caused by the Hepatitis A virus (HAV) occur worldwide. Molecular epidemiology is crucial to understanding the transmission dynamics; however, the current genotype assignment fails to provide useful epidemiologic information. We classified HAV sequences available in GenBank based on 460 bp of the VP1/2A region in clades. Additionally, we associated the site of isolation of the strains with the country's HAV endemicity. We analyzed 1369 sequences available in GenBank up to December 2023 which fulfilled inclusion criteria for our study. The collection date ranged from 1957 to 2023, and genotypes IA (n = 986) and IB (n = 290) comprised the majority of sequences. Sequences were assigned to 70 different clades; sequences from most clades (n = 36) were detected in one country or a few countries within a single continent, while sequences of only 9 clades were detected in more than two continents. Countries with lower HAV endemicity showed higher diversity of clades compared with countries with higher HAV endemicity. In addition, multinational HAV outbreaks were associated with specific clades. In conclusion, characterization of HAV strains below the genotype level should be helpful to analyze transmission patterns within and between countries.

Background/Objectives: Long non-coding RNAs (lncRNAs) have been identified as potential biomarkers for cancer diagnosis and prognosis. In the present study, we proposed the analysis of four lncRNAs as a diagnostic support candidate for the follow-up of leukemia patients. The aim of this study was to characterize the expression of BALR6, LINC-PINT, MEG3, and ZEB1-AS1 in patients with B-cell acute lymphoblastic leukemia (B-ALL) at diagnosis and at the end of remission induction therapy. Methods: B-ALL diagnosis and MRD assessment were performed by flow cytometry, while lncRNA expression levels were quantified using TaqMan probe-based assays. Results: Fifteen pediatric patients with B-ALL were followed longitudinally. MRD evaluation identified seven refractory and eight remitted patients. Significant expression changes were observed for MEG3 in remitted patients and for BALR6 and LINC-PINT in refractory patients. No statistically significant differences were detected for ZEB1-AS1. Conclusions: Changes in MEG3, LINC-PINT, and BALR6 lncRNA expression are associated with treatment response and MRD status in pediatric B-ALL, supporting their potential role as complementary biomarkers to conventional MRD monitoring.