How environmental stress affects the impacts of parasites
How environmental stress affects the impacts of parasites
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DOI：
10.4319/lo.1999.44.3_part_2.0925
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发表时间：
1999-05-01
影响因子：
4.5
通讯作者：
Kuris, AM
中科院分区：
文献类型：
--
作者：
Lafferty, KD;Kuris, AM
寄生虫几乎存在于每个种群中。他们经常以复杂的方式与其他压力源相互作用。在某些情况下，这种相互作用可能会对宿主人口产生不成比例的负面影响。在其他情况下，压力可能会改善寄生的影响。在这里，我们说明了四种类型的环境压力与传染病的交叉点。首先，污染物可能通过增加宿主易感性或通过增加中间宿主和媒介的丰度来增加寄生性。污染物也可以减少寄生，如果受感染的主机遭受差异高死亡率，寄生虫更容易受到污染比他们的主机，或如果污染物产生负面影响中间主机或载体。这些影响取决于相互作用的特定寄生虫和污染物。其次，栖息地的改变，如蓄水或发展，可以影响中间宿主和媒介种群，使其伴随的寄生虫的丰度增加或减少。第三，渔业可能影响已经受到疾病影响的人口。然而，它们可能会降低宿主种群的密度，使其低于持续传播的阈值，从而使寄生虫种群不再持续存在。第四，引入的物种可能会将新的疾病引入易感的本地种群，或者如果它们入侵时没有来自其本地范围的寄生虫，它们可能会获得优势。这些相互作用的复杂性和普遍性是很好的论据，考虑寄生在评估水生系统的压力。
Parasites occur in nearly every population. They often interact in complex ways with other stressors. In some cases, the interaction may lead to a disproportionately negative effect on the host population. In other cases, the stressor may ameliorate the effects of parasitism. Here we illustrate intersections of four types of environmental stressors with infectious diseases. First, pollutants may increase parasitism by increasing host susceptibility or by increasing the abundance of intermediate hosts and vectors. Pollutants can also decrease parasitism if infected hosts suffer differentially high mortality, parasites are more susceptible to pollution than their hosts, or if pollutants negatively affect intermediate hosts or vectors. These effects vary depending on the particular parasite and pollutant that interact. Second, habitat alterations such as impounding water or development can affect both intermediate host and vector populations such that the abundance of their attendant parasites is either increased or reduced. Third, fisheries can impact populations already stressed by disease. However, they may act to lower the density of a host population below the threshold for sustained transmission to such an extent that the parasite population can no longer persist. Fourth, introduced species may introduce new diseases to susceptible native populations or they may gain an advantage if they invade without the parasites from their native range. The complexity and ubiquity of these interactions are good arguments for considering parasitism when evaluating stressors of aquatic systems.