The Genetic Characteristics of Human Coronavirus OC43 in Cases of Severe Acute Respiratory Infection/ 严重急性呼吸道感染病例中人冠状病毒OC43基因特征分析

Human coronavirus (HCoV) is one of the important pathogens of human respiratory tract infection In order to clarify the genetic characteristics of HCoV-OC43 in severe acute respiratory infection (SARI) cases at the molecular level, a total of 374 samples obtained from SARI cases in Henan Province, China, in 2019 were screened for the nucleic acids of HCoV-OC43 by real time polymerase chain reaction (PCR) Reverse transcription-PCR amplification and sequencing of spike (S), RNA-dependent RNA polymerase (RdRp) and nucleocapsid (N) was carried out in samples with positive detection of the nucleic acids of HCoV-OC43 Upon combination of 42 representative sequences obtained from the GenBank database，phylogenetic trees were constructed based on three full-length sequences of S, RdRp and N genes The HCoV-OC43 strains obtained from SARI cases were genotyped and the genetic characteristics of three target genes were analyzed Variations in the amino acids of S protein (an important antigen of HCoV-OC43) were also analyzed Results showed that 15（4 01%）out of 374 samples from SARI cases were positive for HCoV-OC43，and the full-length sequences of S，RdRp and N genes were obtained from 4 out of 15 samples Based on the phylogenetic trees of these three target genes，three strains belonged to the G genotype and one strain belonged to the H genotype Analysis of the amino-acid variations of S protein indicated that there were three special sites of amino-acid variation（L272P，P516S and S902A）among the G genotype strains in 2019，including the three strains in our study and USA /MN306041/SC0810/2019 Another special variation in amino acids（N484D）was found among the H genotype strains in 2019, including one strain in our study and USA/MN306043/SC0841/2019 Based on the genotype identification and genetic characteristics of HCoV-OC43 strains from SARI cases in Henan Province, in 2019, baseline data for the study of molecular epidemiology of HCoV-OC43 in China have been provided