Genomic Epidemiological Characteristics of Enteric Adenovirus F40 and F41 in Yantai, China, from 2022 to 2023

This study aims to investigate the genomic epidemiological characteristics of enteric adenovirus types F40 and F41 circulating in Yantai from August 2022 to August 2023, with a focus on genetic diversity, recombination events, and their potential implications for public health and vaccine development. A total of 1200 stool specimens were collected from patients with suspected viral diarrhea, and 47 human adenovirus F subgroup positive samples in Yantai were analyzed. HAdV-F subgroup nucleic acid detection and whole-genome sequencing were performed to identify virus types and single nucleotide variants (SNVs). Phylogenetic and recombination analyses were conducted, and viral protein structures were predicted using AlphaFold3. HAdV-F40 strains exhibited relative genetic conservation, with mutations primarily localized to the fiber gene. In contrast, HAdV-F41 strains displayed pronounced genetic divergence, with a higher mutation burden in the hexon gene. Recombination analysis revealed clear intra-typic recombination events within HAdV-F41, particularly in the hexon gene region. Structural modeling indicated that although the overall protein architecture remained intact, amino acid changes in key antigenic regions may influence immune evasion. HAdV-F40 and HAdV-F41 strains circulating in Yantai show marked genetic diversity. Notably, HAdV-F41 undergoes significant recombination events that may enhance viral adaptability and immune escape. These findings provide important molecular evidence to inform future surveillance strategies and vaccine antigen design for HAdV-F subgroups.