Epidemiological characteristics and virulence of EV71 in Guangdong province / 实用医学杂志

ABSTRACT

Objective To study the factors influencing epidemiological characteristics and virulence of Enterovirus 71 (EV71) in Guangdong province from 2008 to 2010. Methods RNA was extracted from collected samples or cultured virus , then reversing transcription into cDNA. We amplified full-length EV71-VP1 using poly-merase chain reaction technology , then conducted sequence alignment and established phylogenetic tree with MEGA software (version 5.0) to confirm the genotype of EV71. The association between severity of clinical symp-toms and sex, age, viral genotype and VP1 variation was also analyzed using Logistic regression. Results The genotype of the predominant epidemical strain was C4a in Guangdong from 2008 to 2010. However , this subtype had already differentiated into 4 subgroups (C4a1- C4a4). There was no correlation between clinical syndrome and sex or viral genotype; the severity of symptoms was negatively correlated with age: before 4 years old, varia-tion A289T can easily lead to severe cases, increasing the risk of infection (P<0.05, OR = 2.360, 95%CI:1.163~ 4.659). Conclusion The main epidemical EV71 strain is C4a1 in Guangdong province. The emerging differen-tiation and simultaneous prevalence should merit attention to strengthen relevant surveillance; and the protection of the susceptible population should be reinforced during EV71 prevalence.