Persistence of canine distemper virus in the Greater Yellowstone Ecosystem's carnivore community
Persistence of canine distemper virus in the Greater Yellowstone Ecosystem's carnivore community
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DOI：
10.1890/09-1225.1
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发表时间：
2010-10-01
影响因子：
5
通讯作者：
Smith, Douglas W.
中科院分区：
文献类型：
--
作者：
Almberg, Emily S.;Cross, Paul C.;Smith, Douglas W.
犬瘟热病毒（CDV）是一种急性、高度免疫的病原体，需要高密度和大量的宿主才能长期持续存在，但CDV在群体较小、分布不均匀的陆地食肉动物中持续存在。我们以大黄石生态系统 (GYE) 狼 (Canis lupus) 和郊狼 (Canis latrans) 中的 CDV 作为案例研究，探讨集合种群结构、宿主人口统计和多宿主传播如何影响 CDV 持久性所需的关键群落规模和空间规模。我们使用随机、空间明确的易感者-暴露-感染-恢复模拟模型来说明宿主空间连通性和人口流动如何相互作用，从而影响当地的流行病动态，例如流行病间期的长度和变化，以及病原体的持久性。鉴于明显缺乏其他已知的持久性机制（例如，携带者或环境状态、人口稠密的宿主、慢性感染或媒介），我们认为 CDV 需要大空间尺度或多宿主传播来实现持久性。目前的 GYE 狼种群可能太小，无法支持地方性 CDV。土狼是一个看似合理的储存宿主，但 CDV 仍需要 50 000-100 000 个体才能实现中等持久性（10 年以上 50%），这相当于 GYE 大小的 1-3 倍（60 000-200 000 km(2)）。郊狼和一般的食肉动物的分布并不均匀。因此，这可能是对 CDV 持久性空间规模的严重低估。然而，第二个有能力的宿主物种的存在可以大大增加 CDV 在小得多的空间尺度上长期持续存在的可能性。尽管目前不建议对 GYE 进行 CDV 管理，但该地区的狼管理者应该预计到与 CDV 相关的周期性但不可预测的种群数量下降，频率为每 2-5 年一次。对此类疫情的认识和监测将有助于对管理活动进行相应的调整，例如规范公共捕猎，从而在受《濒危物种法》保护超过 30 年之后，顺利过渡到国家狼管理和保护。
Canine distemper virus (CDV) is an acute, highly immunizing pathogen that should require high densities and large populations of hosts for long-term persistence, yet CDV persists among terrestrial carnivores with small, patchily distributed groups. We used CDV in the Greater Yellowstone ecosystem's (GYE) wolves (Canis lupus) and coyotes (Canis latrans) as a case study for exploring how metapopulation structure, host demographics, and multi-host transmission affect the critical community size and spatial scale required for CDV persistence. We illustrate how host spatial connectivity and demographic turnover interact to affect both local epidemic dynamics, such as the length and variation in inter-epidemic periods, and pathogen persistence using stochastic, spatially explicit susceptible-exposed-infectious-recovered simulation models. Given the apparent absence of other known persistence mechanisms (e. g., a carrier or environmental state, densely populated host, chronic infection, or a vector), we suggest that CDV requires either large spatial scales or multi-host transmission for persistence. Current GYE wolf populations are probably too small to support endemic CDV. Coyotes are a plausible reservoir host, but CDV would still require 50 000-100 000 individuals for moderate persistence (>50% over 10 years), which would equate to an area of 1-3 times the size of the GYE (60 000-200 000 km(2)). Coyotes, and carnivores in general, are not uniformly distributed; therefore, this is probably a gross underestimate of the spatial scale of CDV persistence. However, the presence of a second competent host species can greatly increase the probability of long-term CDV persistence at much smaller spatial scales. Although no management of CDV is currently recommended for the GYE, wolf managers in the region should expect periodic but unpredictable CDV-related population declines as often as every 2-5 years. Awareness and monitoring of such outbreaks will allow corresponding adjustments in management activities such as regulated public harvest, creating a smooth transition to state wolf management and conservation after >30 years of being protected by the Endangered Species Act.