The pathogen spectrum of influenza-like illness in Guilin, China, 2023-2024

To investigate the pathogen spectrum and epidemiological characteristics of influenza-like illness (ILI) in Guilin, China, from 2023 to 2024.

Between October 2023 and October 2024, 400 pharyngeal swabs were collected weekly from ILI patients and 18 respiratory pathogens were detected using quantitative real-time PCR (qPCR). Pathogen spectrum and epidemiological characteristics were analyzed.

Of the 400 samples, the overall pathogen-positive rate was 74.0% (296/400). Among the detected pathogens, Influenza (Flu) was the main pathogen (44.0%, 176/400), followed by SARS-CoV-2 (12.3%, 49/400) and Mycoplasma pneumoniae (MP) (8.8%, 35/400). The detection rate is highest in the age group of 45-59 years old, reaching 91.7%. The detection rates for Flu, SARS-CoV-2, MP, HAdV, RSV, EV, and HPIV showed significant differences among age groups (p < 0.05). The peak period of positive detection rate was autumn and winter (Nov 2023-Mar 2024). Flu (H3N2 and IBV) dominated in autumn and winter, but was gradually replaced by SARS-CoV-2 and MP thereafter. By autumn 2024, SARS-CoV-2 and HRV were predominant. Co-infections were identified in 14.2% (42/296) of positive cases, with the combination of Flu and MP being the most common (19.0%).

During the study period, ILI in Guilin was primarily driven by Flu, which co-circulated with other pathogens including SARS-CoV-2 and MP, demonstrating distinct seasonal patterns and demographic distributions.