ABSTRACT
Objective@#To understand the pathogen spectrum of severe hand, foot and mouth disease (HFMD), and analyze the genetic characteristics of enterovirus A71(EV-A71) in Xianyang in 2018.@*Methods@#Totally 67 specimens of severe cases of HFMD were collected. Enteroviruses associated with HFMD were detected by real-time PCR and the genotypes of enteroviruses were identified by VP4 region of enteroviruses. The nucleotide and amino acid sequences of VP1 region of EV-A71 were analyzed.@*Results@#A total of 30 samples were positive for enterovirus among samples from 67 severe cases with HFMD, including 9 cases of EV-A71, 11 cases of coxsackievirus A6 (CV-A6), 5 cases of coxsackievirus A16 (CV-A16), 2 cases of coxsackievirus A10 (CV-A10) and 2 cases of coxsackievirus A4 (CV-A4). The nucleotide and amino acid homologies of EV-A71 among 4 strains reached 96.7%-99.9% and 99.3%-100% respectively. The 4 strains of EV-A71 belonged to C4a subtypes by phylogenetic analysis. The six amino acid composite model was KADSTV in 4 strains of EV-A71. The EF region and GH region in antigenic determinants of 4 strains of EV-A71 kept consistent with representative reference strains, however, the EV-A71 SZK222 and SZK497 strains developed mutation at site 93 (I93V) of BC loop region.@*Conclusions@#EV-A71 and CV-A6 are major agents of severe HFMD in Xianyang in 2018. The genotype of EV-A71 belonged to C4a subtype and the VP1 gene did not show more mutations.
ABSTRACT
Objective To study the epidemiology of hand,foot,and mouth disease (HFMD) and the spectrum of serotypes in the other enterovirus (EV) (non-EV-A71 and non-Coxsaekievirus group A 16,CV-A 16) from 2016 to 2017 in Guangzhou,to provide the basis for its treatment,prevention and control.Methods Enteroviruses universal type,EV-A71 and CV-A16 were detected by real time reverse transeription-polymerase chain reaction in the specimens from HFMD suspected patients from 2016 to 2017.The positive specimens of non-EV-A71 and non-CV-A16 were amplified and sequenced based on 5'-untranslated region (UTR) region.The spectrum of serotypes was analyzed with BLAST in NCBI on the basis of 5'-UTR region.Results A total of 25779 specimens from HFMD patients were collected during 2016-2017,16 300 (63.23 ％) of which were positive.The positive rates of EV-A71,CV-A16,non-EV-A71 and non-CV-A16 were 4.57％ (1 178/25 779),12.70％ (3 274/25 779) and 45.96％ (11 848/25779),respectively.The average positive rate of non-EV-A71 and non-CV-A16 in 2017 was 55.68％,which was higher than that in 2016.Sequence analysis showed that there were 16 genotypes in 95 non-EV-A71 and non-CV-A16 positive specimen,including CV-A6,CV-A10,CV-A4,CV-A2,CV-A8,CV-A12,CV-A9,Coxsakievirus B5 (CV-B5),CV-B2,CV-B4,CV-B3,Echovirus 1 (E1),E16,E30,E2 and E18.CV-A6 (26.32％),and CV-A10 (15.79％) were the most common genotypes,followed by CV-A4 (6.32％)、CV-A8(4.21％),and CV-A2 (4.21％).Conclusions The infection rate of EV-A71 is very low during 2016-2017.From April to July 2016,there is a small peak of CV-A16 infection.The non-EV-A71 and non-CV-A16 enterovirus becomes the main causative agent of HFMD during 2016 to 2017.CV-A6 and CV-A10 are the most prevalent pathogens of non-EV-A71 and non-CV-A16 enterovirus.Research and monitoring of CV-A6,CV-A10 as the main non-EV-A71and non-CV-A16 virus should be strengthened.