Allard Antoine, Althouse Benjamin M, Hébert-Dufresne Laurent, Scarpino Samuel V
Centre de Recerca Matemàtica, Edifici C, Campus Bellaterra, Bellaterra, Barcelona, Spain.
Institute for Disease Modeling, Bellevue, Washington, United States of America.
PLoS Pathog. 2017 Sep 21;13(9):e1006633. doi: 10.1371/journal.ppat.1006633. eCollection 2017 Sep.
Pathogens often follow more than one transmission route during outbreaks-from needle sharing plus sexual transmission of HIV to small droplet aerosol plus fomite transmission of influenza. Thus, controlling an infectious disease outbreak often requires characterizing the risk associated with multiple mechanisms of transmission. For example, during the Ebola virus outbreak in West Africa, weighing the relative importance of funeral versus health care worker transmission was essential to stopping disease spread. As a result, strategic policy decisions regarding interventions must rely on accurately characterizing risks associated with multiple transmission routes. The ongoing Zika virus (ZIKV) outbreak challenges our conventional methodologies for translating case-counts into route-specific transmission risk. Critically, most approaches will fail to accurately estimate the risk of sustained sexual transmission of a pathogen that is primarily vectored by a mosquito-such as the risk of sustained sexual transmission of ZIKV. By computationally investigating a novel mathematical approach for multi-route pathogens, our results suggest that previous epidemic threshold estimates could under-estimate the risk of sustained sexual transmission by at least an order of magnitude. This result, coupled with emerging clinical, epidemiological, and experimental evidence for an increased risk of sexual transmission, would strongly support recent calls to classify ZIKV as a sexually transmitted infection.
在疫情爆发期间，病原体往往遵循不止一种传播途径——从艾滋病毒的共用针头和性传播，到流感的小液滴气溶胶和污染物传播。因此，控制传染病爆发通常需要确定与多种传播机制相关的风险。例如，在西非埃博拉病毒疫情期间，权衡葬礼传播与医护人员传播的相对重要性对于阻止疾病传播至关重要。因此，关于干预措施的战略政策决策必须依赖于准确确定与多种传播途径相关的风险。当前的寨卡病毒（ZIKV）疫情对我们将病例数转化为特定传播途径传播风险的传统方法提出了挑战。至关重要的是，大多数方法将无法准确估计主要由蚊子传播的病原体的持续性传播风险——例如寨卡病毒的持续性传播风险。通过对多途径病原体的一种新数学方法进行计算研究，我们的结果表明，以前的流行阈值估计可能会将持续性传播风险低估至少一个数量级。这一结果，再加上新出现的关于性传播风险增加的临床、流行病学和实验证据，将有力支持最近将寨卡病毒归类为性传播感染的呼吁。
