Manore Carrie A, Ostfeld Richard S, Agusto Folashade B, Gaff Holly, LaDeau Shannon L
Center for Computational Science Tulane University New Orleans, LA, United States of America.
Theoretical Biology and Biophysics Los Alamos National Laboratory Los Alamos, NM, United States of America.
PLoS Negl Trop Dis. 2017 Jan 17;11(1):e0005255. doi: 10.1371/journal.pntd.0005255. eCollection 2017 Jan.
The recent spread of mosquito-transmitted viruses and associated disease to the Americas motivates a new, data-driven evaluation of risk in temperate population centers. Temperate regions are generally expected to pose low risk for significant mosquito-borne disease; however, the spread of the Asian tiger mosquito (Aedes albopictus) across densely populated urban areas has established a new landscape of risk. We use a model informed by field data to assess the conditions likely to facilitate local transmission of chikungunya and Zika viruses from an infected traveler to Ae. albopictus and then to other humans in USA cities with variable human densities and seasonality. Mosquito-borne disease occurs when specific combinations of conditions maximize virus-to-mosquito and mosquito-to-human contact rates. We develop a mathematical model that captures the epidemiology and is informed by current data on vector ecology from urban sites. The model demonstrates that under specific but realistic conditions, fifty-percent of introductions by infectious travelers to a high human, high mosquito density city could initiate local transmission and 10% of the introductions could result in 100 or more people infected. Despite the propensity for Ae. albopictus to bite non-human vertebrates, we also demonstrate that local virus transmission and human outbreaks may occur when vectors feed from humans even just 40% of the time. Inclusion of human behavioral changes and mitigations were not incorporated into the models and would likely reduce predicted infections. This work demonstrates how a conditional series of non-average events can result in local arbovirus transmission and outbreaks of human disease, even in temperate cities.
近期，蚊媒病毒及其相关疾病在美洲地区的传播促使人们对温带人口密集地区的风险进行新的数据驱动评估。一般认为温带地区蚊媒重大疾病的风险较低；然而，亚洲虎蚊（白纹伊蚊）在人口密集的城市地区的传播形成了新的风险格局。我们使用一个基于实地数据的模型，来评估在美国不同人口密度和季节性的城市中，可能促进基孔肯雅病毒和寨卡病毒从受感染旅行者传播至白纹伊蚊，进而传播给其他人群的条件。当特定的条件组合使病毒与蚊子以及蚊子与人类的接触率最大化时，蚊媒疾病就会发生。我们开发了一个数学模型，该模型涵盖了流行病学，并以城市地区当前的病媒生态学数据为依据。该模型表明，在特定但现实的条件下，感染旅行者进入一个高人口、高蚊子密度的城市，50%的引入情况可能引发本地传播，10%的引入情况可能导致100人或更多人感染。尽管白纹伊蚊倾向于叮咬非人类脊椎动物，但我们也证明，当病媒仅40%的时间以人类为食时，仍可能发生本地病毒传播和人类疫情。模型未纳入人类行为变化和缓解措施，而这些因素可能会减少预测的感染情况。这项研究表明，即使在温带城市，一系列特定的非平均事件也可能导致本地虫媒病毒传播和人类疾病爆发。
