ABSTRACT
Objective To analyze the variations and drug resistance of influenza A (H3N2) viruses in Jiangsu Province in 2017, and provide evidence for prevention and control strategies on influenza. Methods Reverse transcription polymerase chain reaction (RT-PCR) was used for the sequencing of H3N2 subtype influenza strains. The influenza reference sequences were obtained from the global shared influenza site GISAID. The sequence alignment and phylogenetic analysis were performed using MAGE7.0 software. Viral resistance was analyzed by a neuraminidase inhibition assay. Results The H3N2 subtype influenza isolates and vaccine strains belonged to the 3C.2a branch of the H3 subtype. Some of the strains showed amino acid mutations on the immune-related sites named N121K, T135K and N171K. The isolates were sensitive to the flu drugs oseltamivir and zanamivir. Conclusion The H3N2 epidemic strains in Jiangsu have genetic recombination within subtypes and are still sensitive to neuraminidase inhibitors. As the H3N2 influenza virus mutations continue, a close monitoring of the viral genetic evolution and the drug resistant genes should be guaranteed.
ABSTRACT
Objective To determine the epidemiological features of hand-foot-and-mouth disease (HFMD) outbreaks and the genetic characteristics of enterovirus type 71 (EV71) isolates from patients in Lianyungang, Jiangsu province in May, 2008. Methods Epidemiological, microbiological, cellular and molecular methods were performed to investigate pathogens and to describe the homogeneity of isolated strains. Results 21 cases were reported in this HFMD outbreak with the attack rate as 20.0%. 3 EV71 virus strains were isolated from 10 stool samples. The nucleotide and amino acid homogeneity of these 3 Jiangsu strain with Anhui Fuyang strains were 97.9%-100.0% and 99.7%-100.0%, respectively. These 4 Jiangsu strains were within genotype C sub-geno group C4 in phylogenetic tree. Data from the follow-up study showed that shedding of EV71 and Coxsackie A 16 virus (CA 16) in the latent period appeared in the outbreak of HFMD. Human beings could be infected by both EV71 virus and CA16 at the same time and could also carry the two viruses. We also discovered that EV71 virus could be expelled out of the human body through stool in the fast week and last for 10 weeks. Conclusion The recently identified EV71 isolates from this HFMD outbreak belonged to sub-geno group CA. Facts as: the release of viruses in the latent period, co-infection or coexisting of two viruses at the same time and super long period of expulsion of toxin exist in EV71 and CA16 did exist.