Epidemiological Surveillance: Genetic Diversity of Rotavirus Group A in the Pearl River Delta, Guangdong, China in 2019

Objective This study aimed to understand the epidemic status and phylogenetic relationships of rotavirus group A(RVA)in the Pearl River Delta region of Guangdong Province,China.Methods This study included individuals aged 28 days–85 years.A total of 706 stool samples from patients with acute gastroenteritis collected between January 2019 and January 2020 were analyzed for 17 causative pathogens,including RVA,using a Gastrointestinal Pathogen Panel,followed by genotyping,virus isolation,and complete sequencing to assess the genetic diversity of RVA.Results The overall RVA infection rate was 14.59%(103/706),with an irregular epidemiological pattern.The proportion of co-infection with RVA and other pathogens was 39.81%(41/103).Acute gastroenteritis is highly prevalent in young children aged 0–1 year,and RVA is the key pathogen circulating in patients 6–10 months of age with diarrhea.G9P[8](58.25%,60/103)was found to be the predominant genotype in the RVA strains,and the 41 RVA-positive strains that were successfully sequenced belonged to three different RVA genotypes in the phylogenetic analysis.Recombination analysis showed that gene reassortment events,selection pressure,codon usage bias,gene polymorphism,and post-translational modifications(PTMs)occurred in the G9P[8]and G3P[8]strains.Conclusion This study provides molecular evidence of RVA prevalence in the Pearl River Delta region of China,further enriching the existing information on its genetics and evolutionary characteristics and suggesting the emergence of genetic diversity.Strengthening the surveillance of genotypic changes and gene reassortment in RVA strains is essential for further research and a better understanding of strain variations for further vaccine development.

Genomic Epidemiology of Imported Cases of COVID-19 in Guangdong Province,China,October 2020–May 2021

Objective The pandemic of severe acute respiratory syndrome coronavirus 2(SARS-Co V-2) has been engendering enormous hazards to the world. We obtained the complete genome sequences of SARSCo V-2 from imported cases admitted to the Guangzhou Eighth People’s Hospital, which was appointed by the Guangdong provincial government to treat coronavirus disease 2019(COVID-19). The SARS-Co V-2 diversity was analyzed, and the mutation characteristics, time, and regional trend of variant emergence were evaluated.Methods In total, 177 throat swab samples were obtained from COVID-19 patients(from October2020 to May 2021). High-throughput sequencing technology was used to detect the viral sequences of patients infected with SARS-Co V-2. Phylogenetic and molecular evolutionary analyses were used to evaluate the mutation characteristics and the time and regional trends of variants.Results We observed that the imported cases mainly occurred after January 2021, peaking in May2021, with the highest proportion observed from cases originating from the United States. The main lineages were found in Europe, Africa, and North America, and B.1.1.7 and B.1.351 were the two major sublineages. Sublineage B.1.618 was the Asian lineage(Indian) found in this study, and B.1.1.228 was not included in the lineage list of the Pangolin web. A reasonably high homology was observed among all samples. The total frequency of mutations showed that the open reading frame 1 a(ORF1 a) protein had the highest mutation density at the nucleotide level, and the D614 G mutation in the spike protein was the commonest at the amino acid level. Most importantly, we identified some amino acid mutations in positions S, ORF7 b, and ORF9 b, and they have neither been reported on the Global Initiative of Sharing All Influenza Data nor published in Pub Med among all missense mutations.Conclusion These results suggested the diversity of lineages and sublineages and the high homology at the amino acid level among imported cases infected with SARS-Co V-2 in Guangdong Province, China.