Epidemiological and genetic characteristics of influenza virus and the effects of air pollution on laboratory-confirmed influenza cases in Hulunbuir, China, from 2010 to 2019

• Published in: Epidemiology and infection Vol. 148; p. e159
• Main Authors: Lu, Bing, Wang, Yingchen, Zhu, Zhansong, Zhang, Zhe, Dong, Tuo, Li, Falong, Gao, Ya, Du, Xiqiao, Qu, Zhangyi
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.01.2020
• Subjects: Air pollution; Air pollution effects; Epidemiology; Exo-a-sialidase; Hemagglutinins; Influenza; Influenza B; Mutation; Original Paper; Outdoor air quality; Pandemics; Particulate emissions; Particulate matter; Pollutants; Statistical analysis; Strains (organisms); Viruses; United States > US; Colorado; China; Michigan; influenza; air pollution; generalised additive model (GAM); seasonality
• ISSN: 0950-2688; 1469-4409; 1469-4409
• DOI: 10.1017/S0950268820001387

ObjectiveA continuous survey on influenza was conducted in Hulunbuir, China from January 2010 to May 2019 to reveal epidemiological, microbiological and air pollutants associated with laboratory-confirmed influenza cases.MethodsInfluenza-like illness and severe acute respiratory infection subjects were enrolled from a sentinel hospital in Hulunbuir during the study period for epidemiological and virological investigation. The association between air pollutants and influenza-positivity rate was assessed by a generalised additive model.ResultsOf 4667 specimens, 550 (11.8%) were tested positive for influenza. The influenza-positivity was highest in the age groups of 5–14 years, 50–69 years and ⩾70 years. We found that the effect of particulate matter ⩽2.5 μm (PM2.5) concentrations on the influenza-positivity rate was statistically significant, particularly on day lag-4 and lag-5. Genetic characterisations showed that (H1N1) pdm09 strains belonged to subclade 6B.1 and that influenza B isolates belonged to subclade 1A-3Del, with significant substitutions in the haemagglutinin and neuraminidase proteins compared with those in the WHO-recommended vaccine strains.ConclusionsElderly individuals and school-age children were at high risk for influenza infection. PM2.5 concentrations showed significant effects on influenza-positivity rate in Hulunbuir, which could be considered in local influenza prevention strategies.