Optimal Control of Rat-Borne Leptospirosis in an Urban Environment
Optimal Control of Rat-Borne Leptospirosis in an Urban Environment
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DOI：
10.3389/fevo.2019.00209
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发表时间：
2019-06-19
影响因子：
3
通讯作者：
Begon, Mike
中科院分区：
文献类型：
--
作者：
Minter, Amanda;Costa, Federico;Begon, Mike
人类通过直接接触动物蓄水池感染钩端螺旋体病，或者更常见的是，接触被动物尿液中排出的钩端螺旋体污染的环境。通过使用灭鼠剂很难控制水库种群，通过栖息地管理减少资源的实施成本很高，在后勤方面也很复杂。在资源有限的情况下，对不同的控制方法组合进行仿真，可以为其在现场的应用提供依据。在这里，我们提出了一个框架，以寻找鼠媒钩端螺旋体病的时间依赖的控制措施，使用最优控制数学模型理论。根据对巴西萨尔瓦多数据的经验分析，建立了挪威鼠(Pettus Norveicus)种群中钩端螺旋体感染的年龄结构模型。我们将这一模型扩展到包括两种临时控制措施，即灭鼠和减少资源，以及两种永久性控制措施，即减少环境中的老鼠载量和钩端螺旋体寿命。最优控制理论寻求与时间相关的最优控制，同时考虑控制措施的成本和感染的“成本”。提出了多种控制情景和最优控制对种群和感染动态的预测效果，以说明临时控制和永久控制相结合的应用。长期控制可降低啮齿动物种群中钩端螺旋体携带率。然而，临时控制也可以减少受感染的老鼠数量，降低对人类的风险。虽然我们的建模重点是一个研究得很好的物种--挪威鼠，但我们的方法也可以应用于其他具有动物和环境宿主的疾病系统，为减少人类感染风险的决策提供信息。
Humans acquire leptospirosis through direct contact with animal reservoirs, or more commonly, contact with the environment contaminated with leptospires shed in animal urine. Reservoir populations can be difficult to control through rodenticide application, and resource reduction via habitat management is costly and logistically complicated to implement. When resources are limited, simulation of different combinations of control methods can inform their application in the field. Here we present a framework to find time-dependent control measures for rodent-borne leptospirosis using optimal control mathematical model theory. An age-structured model for leptospire infection in a Norway rat (Pettus norvegicus) population was developed, informed by empirical analyses of data from the city of Salvador, Brazil. We extended this model to include two temporary control measures, rodenticide, and resource reduction, and two permanent control measures, reducing rat carrying capacity and leptospire lifespan in the environment. Optimal control theory seeks the optimum time-dependent controls while taking into account both the cost of the control measures and the "cost" of infection. Multiple control scenarios and the predicted effect of the optimal controls on the population and infection dynamics are presented to illustrate the applications of combinations of temporary and permanent controls. Permanent controls lead to a reduction in prevalence of leptospiral carriage in the rodent population. However, temporary controls can also achieve a reduction in the number of infected rats low enough to reduce risk to humans. Although we focus our modeling on a well-studied species, the Norway rat, our approach can be applied to other disease systems with animal and environmental reservoirs to inform decisions to reduce the risk of human infection.