Investigation of the genotype III to genotype I shift in Japanese encephalitis virus and the impact on human cases
Investigation of the genotype III to genotype I shift in Japanese encephalitis virus and the impact on human cases
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DOI：
10.1007/s12250-015-3621-4
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发表时间：
2015-06-01
影响因子：
5.5
通讯作者：
Rayner, Simon
中科院分区：
文献类型：
--
作者：
Han, Na;Adams, James;Rayner, Simon
日本脑炎是一种蚊子传播的疾病，是亚太地区病毒性脑炎的主要原因。乙型脑炎病毒（JEV）根据核苷酸序列在系统发育上可分为5种基因型。近年来，基因I型（GI）已经取代基因III型（GIII）成为主要谱系，但这种取代事件背后的机制需要阐明。在早期的研究中，我们比较了两种基因型的宿主随时间的变化，观察到GI似乎已经进化到在复制周期中更有效地感染宿主，以降低对人类等次级宿主的传染性为代价。为了进一步研究这一现象，我们收集了人类病例的乙脑病毒监测数据，并结合序列数据，生成了来自7个亚太国家和地区的基因型/病例概况，以表征GI/GIII流离失所事件。我们发现，当获得全面和一致的疫苗接种和监测数据，并且在明确的时间段内发生gii到GI的转变时，JEV人间病例在统计上显着下降。我们的研究结果进一步支持了GI在感染人类方面效果较差的论点，人类是一个死角宿主。然而，实验研究是必要的，以证实这一假设。该研究强调了流行病调查替代方法的价值，以及有效收集数据对疾病监测和控制的重要性。
Japanese encephalitis is a mosquito borne disease and is the leading cause of viral encephalitis in the Asia-Pacific area. The causative agent, Japanese encephalitis virus (JEV) can be phylogenetically classified into five genotypes based on nucleotide sequence. In recent years, genotype I (GI) has displaced genotype III (GIII) as the dominant lineage, but the mechanisms behind this displacement event requires elucidation. In an earlier study, we compared host variation over time between the two genotypes and observed that GI appears to have evolved to achieve more efficient infection in hosts in the replication cycle, with the tradeoff of reduced infectivity in secondary hosts such as humans. To further investigate this phenomenon, we collected JEV surveillance data on human cases and, together with sequence data, and generated genotype/case profiles from seven Asia-Pacific countries and regions to characterize the GI/GIII displacement event. We found that, when comprehensive and consistent vaccination and surveillance data was available, and the GIII to GI shift occurred within a well-defined time period, there was a statistically significant drop in JEV human cases. Our findings provide further support for the argument that GI is less effective in infecting humans, who represent a dead end host. However, experimental investigation is necessary to confirm this hypothesis. The study highlights the value of alternative approaches to investigation of epidemics, as well as the importance of effective data collection for disease surveillance and control.