Background: This study investigated the epidemiological and spatiotemporal characteristics of scarlet fever in Guangzhou, China, and provided a scientific basis for the formulation and optimization of prevention and control strategies. Methods: The epidemiological profile of scarlet fever was systematically reviewed using descriptive analysis. We used the Moran’s I, local indicators of spatial association, and the retrospective spatiotemporal scanning statistical analysis to study the spatiotemporal aggregation phenomenon of scarlet fever in Guangzhou. Results: From 2005 to 2024, 9,601 scarlet fever cases were reported within Guangzhou, with an annual average morbidity of 3.16 per 100,000. Joinpoint regression analysis indicated a statistically significant overall upward trend in scarlet fever incidence (AAPC = 17.26%, p < 0.001), characterized by four phases: low-incidence phase, upsurge phase, COVID-19-affected phase and post COVID-19 rebound phase. Seasonal distribution exhibited a dual-modal pattern, and the crest of transmission occurred from April to June and November to the following January. Demographically, cases mainly occurred among males and kindergarten children aged 3–6 years. Notably, during the post COVID-19 rebound phase, the proportion of cases among students, particularly those aged 7–10 years, increased substantially, becoming a major affected group nearly comparable to kindergarten children. Spatially, higher incidence was observed within central urban districts and expanding peri-urban growth centers. Spatiotemporal scanning identified ten statistically significant clusters, characterized by an expansion toward expanding peri-urban growth centers, such as Licheng in Zengcheng, alongside a resurgence in traditional central urban areas like Meihuacun in Yuexiu, Baihedong in Liwan and their surrounding regions. Conclusions: This study reveals a significant spatial-temporal clustering of scarlet fever in Guangzhou from 2005 to 2024, characterized by an overall upward trend and a notable recent resurgence. The high-risk regions were predominantly localized within the central urban regions and expanding peri-urban growth centers, such as Helong, Licheng, Meihuacun, and their surrounding regions. The outbreak mostly affects kindergarten children aged 3–6 years and students aged 7–10 years, with winter and spring as peaks. Control strategies should target high-risk seasons, populations and regions to reduce scarlet fever cases.

Objective: We aimed to elucidate the epidemiological characteristics and co-infection status of HBoV in Guangzhou and to investigate the potential recombination events and alterations in antigenic properties among circulating HBoV strains. Methods: Utilizing respiratory specimens collected from patients at sentinel surveillance hospitals in Guangzhou between August 2023 and December 2025, multiplex pathogen detection was performed. We describe the temporal and demographic distribution of HBoV in Guangzhou and determine its co-infection patterns. Subsequent sequence analysis focused on identifying potential recombination events and characterizing antigenic properties. Results: The epidemiological features of HBoV in Guangzhou exhibited a primary epidemic peak around the autumn season, followed closely by a secondary peak. HBoV infection was predominantly observed in children under three years of age. Co-infections with rhinovirus and parainfluenza virus were common. Whole-genome sequencing yielded 15 complete HBoV genome sequences. Recombination analysis and verification suggested potential recombination events in two of these sequences. A comparative analysis of the antigenic characteristics of one identified recombinant strain, GZ-2024-20891, against its putative parental strains and domestic prevalent strains revealed potential alterations in its antigenic characteristic. Conclusions: Bocavirus is highly prevalent among young children under 3 years of age, with a secondary peak following the main epidemic peaks around autumn in Guangzhou. Genetic recombination and potential antigenic alteration were detected in bocavirus.