ABSTRACT
Objective@#To analyze the genotypes, amino acid vatiations and molecular epidemiological characteristics of respiratory syncytial virus (RSV) infection in pediatric patients in Gansu province for the future research.@*Methods@#A total of 4 556 respiratory tract specimens were colleted from pediatric patients under 10 years of age in five cities in Gansu from 2012 to 2017. These specimens were tested for RSV and its subtypes.The coding region of the RSV G gene was amplified using reverse transcription-polymerase chain reaction (RT-PCR) and sequenced for RSV positive specimens. Sequences were edited using DNA Star software. Sequence alignment and phylogenetic trees were built by MEGA 6.0 software.@*Results@#Out of 4 556 specimens, 1 135 (24.91%) were positive for RSV, totally 216 G protein sequences were obtained. RSV A isolates were clustered into three genotypes: NA1、NA3 and ON1. The nucleotides and amino-acid homology was 84.9%-100% and 77.3%-100%, respectively. The nucleotides and amino-acid homology between this study and prototype long strain was 81.2%-83.3% and 74.1%-88.0%. RSV B isolates were clustered into only BA9 one genotypes. The nucleotides and amino-acid homology was 97.7%-100% and 95.8%-100%, respectively. The nucleotides and amino-acid homology between this study and prototype CH18537 strain was 84.9%-85.7% and 77.9%-80.1%.@*Conclusions@#The genetic characteristics and the amino-acid changes were analyzed systematically using data of RSV G gene collected from 2012 to 2017 in Gansu province in this study. These data were used for analyses of the etiology, control and prevention of RSV infection.
ABSTRACT
Objective@#To analyze the epidemiological and etiological characters of hand, foot and mouth disease ( HFMD ) in Gansu during 2013 to 2015 and provide evidence for the development of effective prevention and control measures.@*Methods@#The descriptive epidemiological analysis was used to analyze the data of HFMD, and the specimens were collected from hospitals to detect the pathogens by RT- PCR or Real-time RT-PCR. The nucleotide sequences of VP1 encoding region of virus strains were amplified by RT-PCR method, and determined and analyzed.@*Results@#Total of 29 934 HFMD cases were reported in Gansu from 2013 to 2015, including 81 severe cases and 2 deaths; the largest number occurred in Lanzhou was 7 053, accounting for 23.56% of the cases in the province. HFMD cases were mostly reported during May to July, accounted for 61.69% in total cases; the male to female ratio was 1.5: 1, and most cases were under the age of five and accounted for 83.02%. A total of 5 251 laboratory confirmed cases were reported, of which the number of cases caused by human enterovirus (HEV) were 2 972, the positive rate was 56.60%. Among the severe 81 cases, the positive rate of HEV was 67.90%, and both of the 2 death cases were infected by EV71. 341 strains of viruses were isolated, the genotyping of VP1 encoding region showed that all the 133 EV71 were C4a; among the 134 CVA16 isolates, 6 were B1a and 128 were B1b.@*Conclusions@#In Gansu province, there is a high infection rate of HFMD in children under the age of five, the proportion of other HEV is more and more, and the incidence is related to the difference of pathogens that showed alternant epidemic characteristics. CVA16 and EV71 viruses have the phenomenon of alternating.