Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, United States of America.
School of Industrial Engineering, Purdue University, West Lafayette, Indiana, United States of America.
PLoS One. 2022 Aug 17;17(8):e0272130. doi: 10.1371/journal.pone.0272130. eCollection 2022.
Eastern Equine Encephalitis (EEE) is an arbovirus that, while it has been known to exist since the 1930's, recently had a spike in cases. This increased prevalence is particularly concerning due to the severity of the disease with 1 in 3 symptomatic patients dying. The cause of this peak is currently unknown but could be due to changes in climate, the virus itself, or host behavior. In this paper we propose a novel multi-season deterministic model of EEE spread and its stochastic counterpart. Models were parameterized using a dataset from the Florida Department of Health with sixteen years of sentinel chicken seroconversion rates. The different roles of the enzootic and bridge mosquito vectors were explored. As expected, enzootic mosquitoes like Culiseta melanura were more important for EEE persistence, while bridge vectors were implicated in the disease burden in humans. These models were used to explore hypothetical viral mutations and host behavior changes, including increased infectivity, vertical transmission, and host feeding preferences. Results showed that changes in the enzootic vector transmission increased cases among birds more drastically than equivalent changes in the bridge vector. Additionally, a 5% difference in the bridge vector's bird feeding preference can increase cumulative dead-end host infections more than 20-fold. Taken together, this suggests changes in many parts of the transmission cycle can augment cases in birds, but the bridge vectors feeding preference acts as a valve limiting the enzootic circulation from its impact on dead-end hosts, such as humans. Our what-if scenario analysis reveals and measures possible threats regarding EEE and relevant environmental changes and hypothetically suggests how to prevent potential damage to public health and the equine economy.
东部马脑炎（EEE）是一种虫媒病毒，虽然自 20 世纪 30 年代以来就已被发现，但最近其病例数有所上升。由于该疾病的严重性，每 3 名有症状的患者中就有 1 人死亡，因此这种发病率的增加尤其令人担忧。目前导致这种高峰的原因尚不清楚，但可能是由于气候、病毒本身或宿主行为的变化。在本文中，我们提出了一种新的东部马脑炎传播的多季节确定性模型及其随机对应模型。模型使用来自佛罗里达州卫生部的数据集进行参数化，其中包含 16 年的哨兵鸡血清转化率数据。探索了地方性和桥梁蚊子媒介的不同作用。如预期的那样，像库蚊属这样的地方性蚊子对 EEE 的持续存在更为重要，而桥梁蚊子则与人类的疾病负担有关。这些模型被用于探索假设的病毒突变和宿主行为变化，包括增加传染性、垂直传播和宿主摄食偏好。结果表明，与桥梁蚊子相比，地方性蚊子传播的变化会更剧烈地增加鸟类中的病例。此外，桥梁蚊子对鸟类的摄食偏好差异 5%，可使死亡宿主的累积感染增加 20 多倍。总的来说，这表明传播周期的许多部分的变化都会增加鸟类中的病例，但桥梁蚊子的摄食偏好会限制其对死亡宿主（如人类）的影响，从而起到阀门的作用。我们的假设情景分析揭示了与东部马脑炎及相关环境变化相关的可能威胁，并假设了如何防止对公共卫生和马业经济的潜在破坏。
