Upsurge in hospitalization of pediatric patients with severe acute respiratory infections in Kolkata and surrounding districts caused by recombinant human respiratory adenovirus type B 7/3

Molecular characterization of human adenoviruses associated with pediatric respiratory infections in Karachi, Pakistan

Human adenoviruses (HAdVs) are a diverse group of viruses associated with respiratory infections in humans worldwide. However, there is a lack of research on the genetic diversity and epidemiology of HAdVs in Pakistan. This study characterized HAdVs in pediatric patients with respiratory tract infections in Karachi, Pakistan, between 2022 and 2023. We analyzed 762 nasopharyngeal samples of children ≤ 5 years. DNA extraction, followed by PCR targeting E2B and hexon genes, was carried out. Data analysis was performed on SPSS 25.0, and phylogenetic analysis of hexon gene was performed on MEGA 11. HAdV was detected in 7.34% (56/762) of patients round the year, but at a significantly higher rate during the winter season. Age was insignificantly associated with HAdV incidence (p = 0.662), but more than 62.5% (35/56) of positive cases were younger than 10 months. The circulating HAdVs were identified as six different types from species B (78.57%) and C (21.42%), with the majority of isolates found to be like B3. HAdV was found to be co-infected with bocavirus (5.4%) and measles (7.14%). These findings revealed a high frequency and genetic diversity of respiratory HAdVs in Karachi, Pakistan. We conclude that periodic and continuous surveillance of adenoviruses and other respiratory pathogens is necessary to improve the prognosis and management of respiratory diseases, thereby reducing the child mortality rate in Pakistan.

Genomic Expedition: Deciphering Human Adenovirus Strains from the 2023 Outbreak in West Bengal, India: Insights into Viral Evolution and Molecular Epidemiology

Understanding the genetic dynamics of circulating Human Adenovirus (HAdV) types is pivotal for effectively managing outbreaks and devising targeted interventions. During the West Bengal outbreak of 2022-2023, an investigation into the genetic characteristics and outbreak potential of circulating HAdV types was conducted. Twenty-four randomly selected samples underwent whole-genome sequencing. Analysis revealed a prevalent recombinant strain, merging type 3 and type 7 of human mastadenovirus B1 (HAd-B1) species, indicating the emergence of recent strains of species B in India. Furthermore, distinctions in VA-RNAs and the E3 region suggested that current circulating strains of human mastadenovirus B1 (HAd-B1) possess the capacity to evade host immunity, endure longer within hosts, and cause severe respiratory infections. This study underscores the significance of evaluating the complete genome sequence of HAdV isolates to glean insights into their outbreak potential and the severity of associated illnesses.

Molecular epidemiology of circulating human adenoviruses among acute respiratory infection patients seeking healthcare facilities in West Bengal, India

Human adenovirus (HAdV) causes acute respiratory infections leading to mortality in children. This study analyzes the circulating respiratory HAdV genotypes in West Bengal, India during 2018-2022 among symptomatic patients. The overall positivity rate was 6.8%, out of which 26.4% were co-infected with other respiratory viruses. Children aged 2 to 5 years were mostly infected. Phylogenetic analysis revealed that the recombinant HAdV-B type 7/3, which has remarkable outbreak potential, predominantly circulated in this region followed by the non-recombinant HAdV-B type 3/3. Moreover, the amino acid sequences encoded by both the hexon and fiber genes of these two circulating strains possessed a few mutations that mostly diverged from the prototype strain, although the divergence was less pronounced in case of the amino acids encoded by the fiber gene of HAdV-B type 3/3. Overall, the results underscore the need for continuous surveillance of respiratory HAdV types to combat future possible epidemics.