A dengue transmission model in Thailand considering sequential infections with all four serotypes
A dengue transmission model in Thailand considering sequential infections with all four serotypes
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DOI：
10.3855/jidc.616
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发表时间：
2009-10-01
影响因子：
1.9
通讯作者：
Ishikawa, Hirofumi
中科院分区：
文献类型：
--
作者：
Chikaki, Eriko;Ishikawa, Hirofumi
背景：登革热/登革出血热在泰国流行，发现所有血清型，主要血清型有不规则变化。虽然几乎所有原发感染都表现为轻微症状或无症状，但对登革热的传染性知之甚少。方法：建立了登革热病毒传播的数学模型，涵盖了所有四种不同血清型相继感染的可能性。该模型与泰国登革热病毒的主要媒介埃及伊蚊的季节性种群动态相结合。将隐性病例对蚊媒传播和抗体依赖性增强的贡献纳入模型。此外，还通过模型模拟检验了“非自然”感染途径的假设，即一个人在交叉免疫期因感染而获得免疫。结果：通过对隐性病例向蚊媒传播概率的比较研究表明，如果隐性病例不具有传染性，则可以在严重疫情发生后立即消灭登革热感染的流行。在“非自然”感染路径假设下的模拟结果显示，主要血清型每年都有变化，暴发时有明显的不规则变化。结论：隐性病例无传染性的假设不符合泰国的实际情况。此外，模拟结果支持“非自然”感染途径对登革热流行有影响。
Background: Dengue fever/dengue haemorrhagic fever is prevalent in Thailand, where all serotypes are found and the dominant serotype has changed irregularly. Although almost all primary infections present with slight symptoms or are asymptomatic, little is known about the infectiousness of dengue fever.Methodology: A mathematical model of the transmission for dengue virus was constructed covering the possibility of sequential infections with all four different serotypes. The model was combined with the seasonal population dynamics of Aedes aegypti, the principal vectors of dengue virus in Thailand. The contributions of inapparent cases in the transmission to mosquito vectors and antibody-dependent enhancement were incorporated into the model. Moreover, the hypothesis of an "unnatural" infection route was examined, where a person acquires immunity by infection during a cross-immunity period, through model simulations.Results: A comparative study on the transmission probabilities of inapparent cases to mosquito vectors showed that the prevalence of dengue infection could be immediately stamped out after a severe outbreak if inapparent cases had no infectiousness. The simulation under an "unnatural" infection route assumption resulted of yearly changes in the dominant serotype and sharp, irregular variations in outbreaks.Conclusion: The supposition that inapparent cases had no infectiousness was not in accord with the actual situation in Thailand. Furthermore, the simulation result supported the "unnatural" infection route as having an influence on epidemics of dengue.