Epidemic Characters of EV-A causing respiratory tract infections in Beijing

Abstract

Objective To investigate the epidemic characters of enterovirus A group (EV-A) causing respiratory tract infections in Beijing. Methods Clinical specimens of acute respiratory tract infection (ARTI) cases were collected from sentinel hospitals in Beijing. Nucleic acids of enteroviruses were purified and were tested by real-time fluorescent PCR. The VP1 gene region were amplified and sequenced for nucleic acids positive samples. The sequences were compared by Enterovirus Genotyping Tool (Version 1.0) to identify the genotypes of the enteroviruses. The statistic analyses of EV-A distribution characters, including time, regions, age groups and disease categories were respectively performed. Results From 2014 to 2018, 31 932 ARTI cases were collected. A total of 810 cases were enterovirus positive. Genotypes were identified in 531 cases with a detection rate of 1.67%, included 280 cases of EV-A, 92 cases of EV-B, 5 cases of EV-C, 45 cases of EV-D, and 64 cases of HRV, while genotypes of 251 cases were not identified. Ten genotypes of EV-A were identified. The dominant genotypes were coxsakievirus (CV)-A2, CV-A4, CV-A6 and CV-A10. The epidemic peak of EV-A occurred between July and September every year. The detection rate of EV-A among patients age between 2 and 4 years old was the highest. The detection rate of EV-A in central urban area was significantly higher than that in suburban area in Beijing. The detection rate of EV-A in the cases with acute upper respiratory tract infections was higher than that in the cases with non-severe or severe pneumonia. Conclusions From 2014 to 2018 in Beijing, the pathogen spectrum of EV-A changed with CV-A2, CV-A4, CV-A6 and CV-A10 to be predominant in turn every year. The differences in seasonality, age groups and regions were obvious. The detection rate of EV-A among cases of upper respiratory tract infections was the highest. Key words: Enterovirus; Genotype; Respiratory tract infection; Epidemic character