Collaborative Research: Community Ecology of Disease: Control of Epidemics by Species Interactions

动物种群中继续出现新的疾病。这一令人不安的趋势引发了关于疾病的挑战性问题，例如，为什么有些人受到感染，而其他人没有？最近，生态学家怀疑其他物种，如那些为宿主提供食物、与宿主争夺食物、捕食生病宿主的物种，可以抑制或促进疾病的传播。因此，与其他物种的相互作用可能会影响野生动物疾病的分布。然而，探索这种可能性需要将流行病学与群落生态学相结合。很少有疾病系统提供这种整合的机会，但Hall和Caceres的目标是利用水生寄生虫（真菌）-宿主（水蚤，水蚤）系统开发一种实验上易于处理的疾病系统。他们将利用几十年来对水蚤的研究，水蚤以藻类为食，与其他浮游动物竞争藻类，也是鱼类和无脊椎动物的猎物。这些相互作用中的每一个都可能影响疾病在水蚤宿主之间的传播。例如，食物资源的数量和质量影响寄生虫感染形式的产生。然而，由于它们消耗但不产生这些传染性形式，其他浮游生物的竞争对手可能会减少疾病。最后，捕食者可能通过吃掉被感染的宿主来抑制疾病。这些机制是复杂的，因此将通过构建数学模型、利用实验改进这些模型以及用流行病观测来检验模型预测来解决。在这项研究中检查的过程和建模工作应该适用于许多其他疾病系统。最终，这项工作将产生能够指导理解和控制野生动物种群疾病的理论。

New diseases continue to appear in animal populations. This disturbing trend prompts challenging questions about disease, such as, why do some populations become infected and not others? Recently, ecologists have suspected that other species, such as those that provide food for hosts, compete with hosts for food, and prey on sick hosts, can inhibit or facilitate disease spread. Therefore, interactions with other species may influence the distribution of wildlife disease. However, an exploration of this possibility requires an integration of epidemiology with community ecology. Few disease systems offer opportunities for such integration, but Hall and Caceres aim to exploit an experimentally tractable one using an aquatic parasite (fungus)-host (water flea, Daphnia) system. They will harness decades of study of Daphnia as grazers of algae, as competitors with other zooplankton for that algae, and as prey for fishes and invertebrates. Each of these interactions likely influences disease spread among the Daphnia hosts. For instance, quantity and quality of food resources influence the production of infective forms of the parasite. However, because they consume but do not produce these infective forms, other planktonic competitors may reduce disease. Finally, predators may inhibit disease by eating infected hosts. These mechanisms are complex and will thus be addressed by constructing mathematical models, refining those models using experiments, and testing model predictions with observations of epidemics. The processes examined in this study and the modeling work should apply to many other disease systems. Ultimately, this work will produce theories that can guide efforts to understand and control disease in wildlife populations.