Laboratory of Virology, Wageningen University, Radix building (#107), Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands.
J Gen Virol. 2010 May;91(Pt 5):1164-72. doi: 10.1099/vir.0.018028-0. Epub 2010 Jan 20.
Variable genomic loci have been employed in a number of molecular epidemiology studies of white spot syndrome virus (WSSV), but it is unknown which loci are suitable molecular markers for determining WSSV spread on different spatiotemporal scales. Although previous work suggests that multiple introductions of WSSV occurred in central Vietnam, it is largely uncertain how WSSV was introduced and subsequently spread. Here, we evaluate five variable WSSV DNA loci as markers of virus spread on an intermediate (i.e. regional) scale, and develop a detailed and statistically supported model for the spread of WSSV. The genotypes of 17 WSSV isolates from along the coast of Vietnam--nine of which were newly characterized in this study--were analysed to obtain sufficient samples on an intermediate scale and to allow statistical analysis. Only the ORF23/24 variable region is an appropriate marker on this scale, as geographically proximate isolates show similar deletion sizes. The ORF14/15 variable region and variable-number tandem repeat (VNTR) loci are not useful as markers on this scale. ORF14/15 may be suitable for studying larger spatiotemporal scales, whereas VNTR loci are probably suitable for smaller scales. For ORF23/24, there is a clear pattern in the spatial distribution of WSSV: the smallest genomic deletions are found in central Vietnam, and larger deletions are found in the south and the north. WSSV genomic deletions tend to increase over time with virus spread in cultured shrimp, and our data are therefore congruent with the hypothesis that WSSV was introduced in central Vietnam and then radiated out.
已经在多个关于白斑综合征病毒（WSSV）的分子流行病学研究中使用了可变基因组座，但尚不清楚哪些座标适合确定 WSSV 在不同时空尺度上的传播的分子标记。尽管先前的工作表明，WSSV 在越南中部发生了多次传入，但 WSSV 是如何传入和随后传播的仍然很大程度上不确定。在这里，我们评估了五个可变 WSSV DNA 座标作为病毒在中间（即区域）尺度上传播的标记，并为 WSSV 的传播建立了一个详细且具有统计学支持的模型。对来自越南沿海的 17 个 WSSV 分离株的基因型进行了分析，以在中间尺度上获得足够的样本并进行统计分析。只有 ORF23/24 可变区是此尺度上的合适标记，因为地理位置相近的分离株显示出相似的缺失大小。ORF14/15 可变区和可变数串联重复（VNTR）座标在此尺度上不适合作为标记。ORF14/15 可能适合研究更大的时空尺度，而 VNTR 座标可能适合较小的尺度。对于 ORF23/24，WSSV 的空间分布存在明显的模式：在越南中部发现最小的基因组缺失，而在南部和北部发现更大的缺失。随着养殖虾中病毒的传播，WSSV 基因组缺失的趋势随着时间的推移而增加，因此我们的数据与 WSSV 最初传入越南中部然后辐射传播的假设一致。
