Introduction Human adenovirus type 14 variant p1 (HAdV-14p1) has been associated with severe respiratory infections worldwide. However, no cases of HAdV-14p1 infection have been reported in China since 2019. HAdV-14 was unexpectedly identified in 2024 in a pediatric patient hospitalized with bronchopneumonia in Chongqing, China. This study aims to elucidate the genetic characteristics of this strain and determine its phylogenetic relationship with previously circulating domestic and international strains. Methods Whole-genome sequencing was performed on the HAdV-14 strain Chongqing2024-115, followed by comprehensive phylogenetic and genetic variation analyses using all publicly available global HAdV-14 genome sequences from the GenBank database. Results Genome-based phylogenetic analysis classified global HAdV-14 strains into two well-supported clades: the HAdV-14 prototype clade and the variant HAdV-14p1 clade. The latter was further subdivided into three distinct subclades (I–III). Chongqing2024-115 clustered closely with earlier HAdV-14p1 subclade III and isolates from Beijing (2012) and Gansu (2013), showing high sequence identity (99.7%–99.9%). Compared with the genome of the HAdV-14 prototype strain (de Wit, AY803294), all three HAdV-14p1 subclades shared 99 specific nucleotide variations, including a six-nucleotide deletion in the knob domain of the fiber gene (nt751–756). The identification of subclade-specific variations and mutations unique to strain Chongqing2024-115 indicates ongoing microevolution within the HAdV-14p1 clade. Conclusions Our results confirm that the contemporary HAdV-14p1 strain shares a common genetic ancestry with earlier Chinese subclade III strains. Considering the association between HAdV-14p1 and severe disease, sustained surveillance is essential to understand better its prevalence, evolution, and impact on public health in China.
Yali et al. (Thu,) studied this question.