Vicente Joaquín, Höfle Ursula, Fernández-De-Mera Isabel García, Gortazar Christian
Instituto de Investigación en Recursos Cinegéticos IREC (CSIC-UCLM-JCCM), Ronda de Toledo s/n., 13005, Ciudad Real, Spain.
Oecologia. 2007 Jul;152(4):655-64. doi: 10.1007/s00442-007-0690-6. Epub 2007 Mar 31.
We studied a macroparasite (Elaphostrongylus cervi, Nematoda) and a microparasite infection (tuberculosis, TB) in red deer (Cervus elaphus) across different populations where managers manipulated host condition, density and aggregation by providing supplemental food. We aimed to test whether and, if so, how persistence and transmission of both parasites differentially varied as host body condition and population density varied. We took account of sex, as red deer life history greatly concerns sex-related traits. Changes in host factors had different consequences for the spread of each parasite type. Individual presence of tuberculosis was positively associated with host density, whereas E. cervi abundance negatively related to host density and enhanced body condition. There was lack of body condition density dependence; and body condition was mainly dependent on the amount of supplemental food provided, but also on habitat quality descriptors. Overall, our results suggest that body condition was improved at the cost of increased host contact rates, which implied an ecological trade-off between acquiring resources to cope with E. cervi, a macroparasite, and concurrent exposure to mycobacteria. By the simultaneous study of both infections, this research suggests that the effects of changes in host number and population structure on disease spread and persistence need to take into account variation in life histories of the parasites. These findings also raise concern about the ecological consequences of diseases and management of wildlife on host life history.
我们研究了在不同种群的马鹿（ Cervus elaphus ）中一种大型寄生虫（鹿圆线虫，线虫纲）和一种微小寄生虫感染（结核病，TB），在这些种群中，管理者通过提供补充食物来控制宿主状况、密度和聚集情况。我们旨在测试随着宿主体况和种群密度的变化，这两种寄生虫的持久性和传播是否以及如何产生差异变化。我们考虑了性别因素，因为马鹿的生活史与性别相关特征密切相关。宿主因素的变化对每种寄生虫类型的传播产生了不同的影响。结核病的个体存在与宿主密度呈正相关，而鹿圆线虫的丰度与宿主密度呈负相关，且与增强的身体状况有关。不存在身体状况对密度的依赖性；身体状况主要取决于提供的补充食物量，但也取决于栖息地质量指标。总体而言，我们的结果表明，身体状况的改善是以增加宿主接触率为代价的，这意味着在获取资源以应对大型寄生虫鹿圆线虫和同时接触分枝杆菌之间存在生态权衡。通过对两种感染的同时研究，本研究表明宿主数量和种群结构的变化对疾病传播和持久性的影响需要考虑寄生虫生活史的差异。这些发现也引发了对疾病的生态后果以及野生动物管理对宿主生活史影响的关注。
