Environmental drivers of biseasonal anthrax outbreak dynamics in two multihost savanna systems
Environmental drivers of biseasonal anthrax outbreak dynamics in two multihost savanna systems
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两个多宿主稀树草原系统双季节炭疽爆发动态的环境驱动因素
DOI：
10.1002/ecm.1526
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发表时间：
2022
影响因子：
6.1
通讯作者：
Mfune, John K. E.
中科院分区：
文献类型：
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作者：
Huang, Yen‐Hua;Kausrud, Kyrre;Hassim, Ayesha;Ochai, Sunday O.;van Schalkwyk, O. Louis;Dekker, Edgar H.;Buyantuev, Alexander;Cloete, Claudine C.;Kilian, J. Werner;Mfune, John K. E.
环境因素是驱动传染病动态的共同力量。我们比较了南非埃托沙国家公园和克鲁格国家公园的炭疽感染的年际和季节性模式。使用来自每个系统的几十年的死亡率数据，我们评估了炭疽动态背后可能的传播机制，研究（1）物种内和物种间的时间病例相关性和（2）炭疽死亡率与环境因素之间的关联，特别是降雨量和归一化植被指数（NDVI），经验动态建模。克鲁格的炭疽病例在病例数上有很大的年际变化，大规模爆发似乎遵循一个大致的十年周期。相比之下，埃托沙的疫情规模较小，每年发生一次。在埃托沙，几十年来，通常受影响的宿主物种保持一致，尽管平原斑马（Equus quagga）变得相对更占优势。在克鲁格，主要宿主物种的更替发生在20世纪90年代之后，以前占主导地位的宿主物种大捻（Tragelaphus strepsiceros）被黑斑羚（Aepyceros melampus）取代。在这两个公园里，炭疽感染都有两个季节性高峰，每个物种一年只有一个高峰。斑马、跳羚（Antidorcas marsupialis）、角马（Connochaetaurinus）和黑斑羚病例在雨季达到高峰，而大象（Loxodonta africana）、捻角羚和布法罗（Syncerus caffer）病例在旱季达到高峰。对于两个公园共享的共同宿主物种，炭疽死亡率在两个系统的同一季节达到峰值。在同一季节病例高峰的宿主物种中，炭疽死亡率大多是同步的，这意味着相似的传播机制或共同的暴露源。在季节之间，一个物种的暴发可能导致下一个季节另一个物种的更多病例。在埃托沙，较高的植被绿色度与更多的斑马和跳羚炭疽死亡率有关，但在克鲁格，大象病例较少。这些结果表明，宿主对不断变化的环境条件的行为反应可能会影响炭疽传播风险，传播机制的差异导致多宿主双季爆发。这项研究揭示了两个热带稀树草原系统中炭疽的动态和潜在的环境驱动因素，从而更好地了解了驱动双季动态和地点之间爆发变化的因素。
Environmental factors are common forces driving infectious disease dynamics. We compared interannual and seasonal patterns of anthrax infections in two multihost systems in southern Africa: Etosha National Park, Namibia, and Kruger National Park, South Africa. Using several decades of mortality data from each system, we assessed possible transmission mechanisms behind anthrax dynamics, examining (1) within‐ and between‐species temporal case correlations and (2) associations between anthrax mortalities and environmental factors, specifically rainfall and the Normalized Difference Vegetation Index (NDVI), with empirical dynamic modeling. Anthrax cases in Kruger had wide interannual variation in case numbers, and large outbreaks seemed to follow a roughly decadal cycle. In contrast, outbreaks in Etosha were smaller in magnitude and occurred annually. In Etosha, the host species commonly affected remained consistent over several decades, although plains zebra (Equus quagga) became relatively more dominant. In Kruger, turnover of the main host species occurred after the 1990s, where the previously dominant host species, greater kudu (Tragelaphus strepsiceros), was replaced by impala (Aepyceros melampus). In both parks, anthrax infections showed two seasonal peaks, with each species having only one peak in a year. Zebra, springbok (Antidorcas marsupialis), wildebeest (Connochaetes taurinus), and impala cases peaked in wet seasons, while elephant (Loxodonta africana), kudu, and buffalo (Syncerus caffer) cases peaked in dry seasons. For common host species shared between the two parks, anthrax mortalities peaked in the same season in both systems. Among host species with cases peaking in the same season, anthrax mortalities were mostly synchronized, which implies similar transmission mechanisms or shared sources of exposure. Between seasons, outbreaks in one species may contribute to more cases in another species in the following season. Higher vegetation greenness was associated with more zebra and springbok anthrax mortalities in Etosha but fewer elephant cases in Kruger. These results suggest that host behavioral responses to changing environmental conditions may affect anthrax transmission risk, with differences in transmission mechanisms leading to multihost biseasonal outbreaks. This study reveals the dynamics and potential environmental drivers of anthrax in two savanna systems, providing a better understanding of factors driving biseasonal dynamics and outbreak variation among locations.