Do scavengers prevent or promote disease transmission? The effect of invertebrate scavenging on Ranavirus transmission
Do scavengers prevent or promote disease transmission? The effect of invertebrate scavenging on
Ranavirus
transmission
复制标题
食腐动物会预防还是促进疾病传播？
作者：
Mitchell Le Sage;Bailey D. Towey;J. Brunner
宿主-寄生虫的相互作用是由更广泛的网络的社区相互作用，从种间竞争捕食者-猎物动态。异种性食腐动物也可能影响寄生虫从传染性尸体的传播，这可能是某些野生动物疾病的重要传染源。一个强大的清道夫社区可以迅速清除尸体和组织，从而防止通过食尸或接触传染性尸体的二次传播。或者，通过在整个环境中传播感染性颗粒和组织，清道夫可能会增加与病原体的偶然接触率，从而增加整体传播。然而，很少有经验的考虑，清道夫可能在传染病的动力学中发挥的对比作用。我们进行了一系列研究，以确定清除无脊椎动物清除长趾蝾螈（Ambystoma macrodactylum）幼虫尸体的效率及其在青蛙病毒3（属：Ranavirus，科：虹彩病毒科）传播中的作用。然后，我们估计一个有效的无脊椎动物的清道夫（家庭：Dytismandae），以确定清除无脊椎动物消耗大量的尸体组织的能力，在现场条件下增加尸体密度的功能反应，可能存在于高患病率的网站。我们发现，清除感染性尸体的清道夫强烈减少传输到幼稚的幼虫。拾荒者在减少尸体传播方面与防止接触尸体的物理屏障一样有效。几乎没有证据表明，清除释放足够的感染组织进入水柱，以对抗直接接触作为一种感染途径。此外，虽然清除率饱和在增加尸体密度，符合II型功能反应，有足够的密度dytiscid幼虫，更不用说其他清除无脊椎动物，在一个调查池塘，理论上防止从尸体传输。我们的研究结果表明，至少在系统中，同种necrophagy是常见的，清道夫社区可以发挥重要作用，减少传输。本文提供了一个简单的语言摘要。
Host–parasite interactions are shaped by the broader web of community interactions, from interspecific competition to predator–prey dynamics. Heterospecific scavengers might also affect parasite transmission from infectious carcasses, which can be an important source of infections for some wildlife diseases. A robust scavenger community can quickly remove carcasses and tissue and thus prevent secondary transmission by necrophagy or contact with infectious carcasses. Alternatively, by spreading infectious particles and tissues throughout the environment, scavengers may increase rates of casual contact with pathogens and thus overall transmission. However, there has been little empirical consideration of the contrasting roles that scavengers might play in infectious disease dynamics. We carried out a series of studies to determine the efficiency with which scavenging invertebrates remove carcasses of Long‐toed Salamander (Ambystoma macrodactylum) larvae and their role in the transmission of frog virus 3 (Genus: Ranavirus, Family: Iridoviridae) from carcasses. We then estimated the functional response of one efficient invertebrate scavenger (Family: Dytiscidae) to increasing carcass densities in field conditions in order to determine the capacity of scavenging invertebrates to consume large amounts of carcass tissue, as may be present at high prevalence sites. We found that removal of infectious carcasses by scavengers strongly reduced transmission to naive larvae. Scavengers were as effective at reducing transmission from a carcass as a physical barrier preventing contact with the carcass. There was little evidence that scavenging released sufficient infectious tissues into the water column to rival direct contact as a route of infection. Moreover, while scavenging rates saturated at increasing carcass densities, consistent with a type II functional response, there were sufficient densities of dytiscid larvae, not to mention other scavenging invertebrates, in a surveyed pond to theoretically prevent transmission from carcasses. Our results suggest that at least in systems in which conspecific necrophagy is common, the scavenger community can play an important role in reducing transmission. A plain language summary is available for this article.