Chow V T, Wan S S, Doraisingham S, Ling A E
Department of Microbiology, Faculty of Medicine, National University of Singapore.
J Med Virol. 1993 Aug;40(4):339-42. doi: 10.1002/jmv.1890400415.
The incidence of varicella in Singapore has been increasing since 1984. In 1991, 17,930 cases were reported in a population of about 3 million. A serological survey completed in 1990 demonstrated that only 43% of the cohort had antibodies to varicella-zoster virus (VZV), indicating inadequate herd immunity. To exclude novel VZV strains, representative VZV isolates from 9 chicken pox and 4 zoster patients were characterised by restriction endonuclease analysis. DNAs were extracted from viral isolates propagated in MRC5 human embryo lung cells and were digested separately with BglII, EcoRI, PstI, SalI, and XbaI enzymes. The cleavage profiles of these VZV strains derived from both chicken pox and zoster lesions revealed no distinct differences. This observation implies that the current upsurge of chicken pox most likely stems from closely related VZV genotypes infecting a susceptible population with insufficient herd immunity. Comparison of the restriction fragments of the Singapore and the Dumas strains revealed polymorphisms of the SalI-D, SalI-E, and XbaI-I fragment lengths, which correlated with variable regions I, II, and III of the VZV genome, thereby representing geographically distinct genotypic variants of VZV.
自1984年以来，新加坡水痘的发病率一直在上升。1991年，在约300万人口中报告了17930例病例。1990年完成的一项血清学调查表明，该队列中只有43%的人具有水痘带状疱疹病毒（VZV）抗体，这表明群体免疫力不足。为了排除新型VZV毒株，对9例水痘患者和4例带状疱疹患者的代表性VZV分离株进行了限制性内切酶分析。从在MRC5人胚肺细胞中繁殖的病毒分离株中提取DNA，并用BglII、EcoRI、PstI、SalI和XbaI酶分别进行消化。这些来自水痘和带状疱疹病变的VZV毒株的切割图谱没有显示出明显差异。这一观察结果表明，目前水痘的激增很可能源于密切相关的VZV基因型感染了群体免疫力不足的易感人群。新加坡毒株和杜马斯毒株的限制性片段比较显示，SalI-D、SalI-E和XbaI-I片段长度存在多态性，这与VZV基因组的可变区I、II和III相关，从而代表了地理上不同的VZV基因型变体。
