School of Natural Resources & Program in the Environment, University of Michigan, Ann Arbor, Michigan, United States of America ; Center for Infectious Disease Dynamics, Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America.
PLoS One. 2013 Sep 20;8(9):e76126. doi: 10.1371/journal.pone.0076126. eCollection 2013.
Most of our knowledge about avian haemosporidian parasites comes from the Hawaiian archipelago, where recently introduced Plasmodiumrelictum has contributed to the extinction of many endemic avian species. While the ecology of invasive malaria is reasonably understood, the ecology of endemic haemosporidian infection in mainland systems is poorly understood, even though it is the rule rather than the exception. We develop a mathematical model to explore and identify the ecological factors that most influence transmission of the common avian parasite, Leucocytozoonfringillinarum (Apicomplexa). The model was parameterized from White-crowned Sparrow (Zonotrichialeucophrys) and S. silvestre / craigi black fly populations breeding in an alpine ecosystem. We identify and examine the importance of altricial nestlings, the seasonal relapse of infected birds for parasite persistence across breeding seasons, and potential impacts of seasonal changes in black fly emergence on parasite prevalence in a high elevation temperate system. We also use the model to identify and estimate the parameters most influencing transmission dynamics. Our analysis found that relapse of adult birds and young of the year birds were crucial for parasite persistence across multiple seasons. However, distinguishing between nude nestlings and feathered young of the year was unnecessary. Finally, due to model sensitivity to many black fly parameters, parasite prevalence and sparrow recruitment may be most affected by seasonal changes in environmental temperature driving shifts in black fly emergence and gonotrophic cycles.
我们对鸟类血孢子虫寄生虫的了解大多来自夏威夷群岛，那里最近引入的疟原虫残余物导致了许多特有鸟类物种的灭绝。虽然入侵疟疾的生态学已被合理理解，但在大陆系统中地方性血孢子虫感染的生态学仍知之甚少，尽管这是常态而不是例外。我们开发了一个数学模型来探索和确定最能影响常见鸟类寄生虫 Leucocytozoon fringillinarum（原生动物）传播的生态因素。该模型是根据高山生态系统中繁殖的白头鹎（Zonotrichia leucophrys）和 S. silvestre / craigi 黑蝇种群的参数化而来的。我们确定并检查了幼雏的早产儿、受感染鸟类在繁殖季节之间的季节性复发对寄生虫持久性的重要性，以及黑蝇出现的季节性变化对高海拔温带系统中寄生虫流行率的潜在影响。我们还使用该模型来确定和估计对传播动力学影响最大的参数。我们的分析发现，成年鸟类和当年幼鸟的复发对于跨多个季节的寄生虫持久性至关重要。然而，区分裸体幼雏和有羽毛的当年幼鸟是不必要的。最后，由于模型对许多黑蝇参数敏感，寄生虫流行率和麻雀的招募可能受环境温度季节性变化的影响最大，这些变化会导致黑蝇出现和生殖周期的变化。
