Modeling the transmission of Perkinsus marinus in the Eastern oyster Crassostrea virginica
Modeling the transmission of Perkinsus marinus in the Eastern oyster Crassostrea virginica
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DOI：
10.1016/j.fishres.2016.08.006
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发表时间：
2017-02-01
影响因子：
2.4
通讯作者：
Guo, X.
中科院分区：
文献类型：
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作者：
Bidegain, G.;Powell, E. N.;Guo, X.
由原生生物 Perkinsus marinus 在东部牡蛎 Crassotrea virginica 中引起的皮肤病是影响牡蛎种群动态的重要死亡来源，导致渔业和水产养殖业遭受重大损失。疾病的快速传播和蔓延最大限度地降低了传播模型的重要性，而过去的模型（基于增殖的模型）假设了简单的密度依赖性传播或定居后的快速感染。此方法仅适用于低人口密度的情况。针对东部牡蛎中的 P. marinus 开发了一个传播模型，该模型解释了疾病动态的季节性变化和宿主之间依赖于密度的觅食（悬浮颗粒）干扰。该模型根据现场观察进行了验证和评估，纳入了活体和死亡个体向水体释放的寄生虫、活牡蛎对寄生虫的消耗、寄生虫在水中的扩散、基于身体负担的剂量依赖性传播、招募和疾病引起的死亡率。根据该疾病目前在牡蛎中的持续存在和流行性质，该模型返回 Dermo 的基本繁殖数 R-0 远大于统一值 (R-0 = 90)。没有获得足够低的人口密度以将 Ro 抑制在 I 以下（即疾病灭绝）。 Ro 还估计了高牡蛎密度（> 300 只 m(-2)），特别是相对较大的牡蛎（类似于 90 毫米），如今这种情况很少见，但在健康牡蛎礁发生普遍过度捕捞之前曾经很常见。在这种情况下，Ro 降至 1 以下，表明高牡蛎密度可以通过干扰觅食和消灭水体中的寄生虫来限制疾病入侵。高强度的补充活动使牡蛎种群达到这样的密度并限制动物流行病的发展。这些结果提供了对从过去人群（Dermo 的影响被认为有限）到当前这种疾病持续流行的性质的转变的深入了解。将该模型进一步耦合到集合种群和水动力模型中可能是支持受皮肤病影响的双壳类种群管理决策的有前途的工具。 (C) 2016 Elsevier B.V. 保留所有权利。
Dermo disease caused by the protistan Perkinsus marinus in Eastern oysters Crassotrea virginica is an important source of mortality impacting oyster population dynamics resulting in substantial losses in fisheries and aquaculture. The rapid transmission and spread of the disease minimized the importance of transmission models and past models (proliferation-based models) assumed simple density-dependent transmission or rapid infection post-settlement. This approach is a good approximation only for low population densities. A transmission model was developed for P. marinus in Eastern oysters that accounts for the seasonal change in disease dynamics and density-dependent foraging (of suspended particles) interference among hosts. The model, verified and evaluated against field observations, incorporates parasite release to the water column from live and dead individuals, parasite consumption by living oysters, the diffusion of parasites in the water, body burden-based dose-dependent transmission, recruitment, and disease-caused mortality. The model returns a basic reproduction number R-0 for Dermo much greater than unity (R-0 = 90) in accordance with the current persistence and pandemic nature of this disease in oysters. No population density is obtained that is low enough to suppress Ro below I (i.e. disease extinction). Ro is also estimated for high oyster densities (>300 individuals m(-2)) and particularly for relatively large oysters (similar to 90 mm), today rare but once common before generalized overfishing occurred on healthy oyster reefs. In this scenario, Ro drops below 1, indicating that high oyster density can limit disease invasion through foraging interference and depletion of parasites in the water column. High intensity recruitment events allow the oyster population to attain such densities and limit the development of epizootics. These results provide insight into the transition from past populations, where Dermo is inferred to have been limited in its impact, to the current persistent and pandemic nature of this disease. Further coupling of this model into metapopulation and hydrodynamic models could be a promising tool to support management decision-making for bivalve populations impacted by Dermo disease. (C) 2016 Elsevier B.V. All rights reserved.