Objective To analyze the epidemiological characteristics of 21 respiratory pathogens in influenza-like illness (ILI) cases in Jing’an District, Shanghai in 2024, and to provide a scientific basis for the prevention and control of respiratory infectious diseases.

Methods Data of 1 907 ILI cases at four sentinel hospitals in Jing’an District were collected from January to December 2024. Nasopharyngeal swab samples were collected and tested for 21 respiratory pathogens using polymerase chain reaction (PCR) methods. Chi-square test and Cochran-Armitage trend test were used for data analyses.

Results Among the 1 907 ILI cases, 1 340 were tested positive (70.27%), including 1 160 (60.83%) virus-positive cases, 424 (22.23%) bacteria-positive cases, and 86 (4.51%) positive cases of other pathogens (fungi, mycoplasma, and chlamydia). The top five viruses by detection rate were: influenza virus (14.84%), SARS-CoV-2 (14.47%), rhinovirus (12.69%), adenovirus (7.08%), and parainfluenza virus (6.71%). The top two bacteria by detection rate were Streptococcus pneumoniae (14.47%) and Haemophilus influenzae (10.33%). Among other pathogens (fungi, mycoplasma, and chlamydia), Mycoplasma pneumoniae showed the highest detection rate (4.30%). In terms of age distribution, statistically significant differences were observed in the detection rates of SARS-CoV-2, Legionella, and Klebsiella pneumoniae (P<0.05), with the highest rates found in individuals aged 65 years and above. Statistically significant differences were also found in the detection rates of rhinovirus, adenovirus, enterovirus, common coronavirus, respiratory syncytial virus, bocavirus, parainfluenza virus, human metapenu-movirus, Streptococcus pneumoniae, Haemophilus influenzae, and Mycoplasma pneumoniae among different age groups (P<0.05), all showing the highest detection rates in the 0‒<15 years age group. In terms of seasonal distribution, SARS-CoV-2, adenovirus, parainfluenza virus, enterovirus, Streptococcus pneumoniae, Haemophilus influenzae, and Mycoplasma pneumoniae showed epidemic peaks in summer; rhinovirus, common coronavirus, bocavirus, and Klebsiella pneumoniae had higher detection rates in autumn. Influenza virus exhibited a peak incidence during winter, while human metapenu-movirus peaked in winter and spring. Significant differences in co-infection detection rates were observed among age groups, with the rate in children aged 0‒<15 years (34.81%) being the highest. The co-infection detection rate was higher in males than in females (P=0.019). Both the single-pathogen detection rate and the co-infection detection rate (P<0.001) varied significantly across seasons: the single-pathogen detection rate was highest in winter (62.06%), while the co-infection detection rate peaked in summer (31.20%) and was lowest in winter (14.52%).

Conclusion Based on detection rates, the main pathogens in the ILI population of Jing’an District, Shanghai, 2024 were influenza virus, SARS-CoV-2, rhinovirus, adenovirus, parainfluenza virus, common coronavirus, enterovirus, Human metapenu-movirus, Streptococcus pneumoniae, Haemophilus influenzae, and Mycoplasma pneumoniae. Pathogen detection rates varied by age and season. Coinfection rates were much higher in children than in adults, higher in males than in females, and peaked in summer while being lowest in winter.