Alternate patterns of temperature variation bring about very different disease outcomes at different mean temperatures.
Alternate patterns of temperature variation bring about very different disease outcomes at different mean temperatures.
复制标题
温度变化的替代模式在不同的平均温度下会带来截然不同的疾病预后。
DOI：
10.7554/elife.72861
复制
发表时间：
2022-02-15
期刊：
影响因子：
7.7
通讯作者：
Donohue I
中科院分区：
文献类型：
--
作者：
Kunze C;Luijckx P;Jackson AL;Donohue I
宿主-寄生虫相互作用的动力学高度依赖于温度，并可能通过气候驱动的热事件的频率和强度的增加而改变。在这里，我们表明，温度变化模式的改变导致宿主和病原体生活史性状的热性能几乎发生数量级的变化，超过平均温度的影响，此外，不同的温度制度对这些性状的影响也不同。我们发现，与恒定温度相比，±3℃的昼夜波动降低了暴露于小孢子虫（Ordospora colligata）寄生虫的大水蚤（Daphnia magna）的感染率和孢子负荷。相比之下，3天的热浪（+6°C）对感染率没有影响，但在16°C时增加了孢子负荷（相对于具有相同平均值的恒温），而在更高温度下减少了负荷。我们的结论是，气候变化模式的变化，加上全球变暖导致的平均温度变化，可能对疾病动态产生深远和意想不到的影响。全球变暖导致平均气温上升，并导致极端温度波动和热浪。这些变化可能影响传染病爆发的时间、地点和频率。这可能对农业、人类健康和野生动物产生深远影响。研究极端温度或温度波动如何改变实验动物的感染，可能有助于科学家更好地了解气候变化对疾病的影响。小型水生无脊椎动物，如水蚤，是这类研究的一个很好的候选者。这些微小的生物可以在温度可控的水族箱里的小玻璃瓶里生长。Kunze， Luijckx等人的研究表明，温度波动和热浪对水蚤的寄生虫感染有复杂的影响。在实验中，水蚤与感染它们的寄生虫关在一起，暴露在恒定的温度、波动的温度或三天的热浪中，同时保持在一个广泛的平均水温范围内。然后，Kunze、Luijckx等人测量了这些条件如何影响水蚤的寿命、繁殖和寄生虫感染。这表明温度变化对水蚤的寿命、繁殖和感染率有独特的影响，这取决于饲养动物的平均水温。在平均水温为16°C时，热浪显著增加了水蚤体内的寄生虫数量，但在平均水温为19°C和22°C时，热浪对水蚤体内的寄生虫数量没有影响或减少了寄生虫数量。同样，在较高的平均水温（bb0 - 24°C）下，温度波动减少了感染寄生虫的水蚤数量和每只感染跳蚤的寄生虫数量。此外，在波动温度下寄生虫能够引起感染的最高温度比在恒定温度下低5°C。Kunze和Luijckx等人的研究表明，持续的高温、温度变化、极端天气事件和平均水温都会影响水蚤的疾病结局。需要更多的研究来评估温度变化如何改变其他生物体的疾病进程，并了解其潜在机制。更多地了解疾病与温度的相互作用将有助于科学家预测气候变化导致的疾病爆发。
The dynamics of host-parasite interactions are highly temperature-dependent and may be modified by increasing frequency and intensity of climate-driven heat events. Here, we show that altered patterns of temperature variance lead to an almost order-of-magnitude shift in thermal performance of host and pathogen life-history traits over and above the effects of mean temperature and, moreover, that different temperature regimes affect these traits differently. We found that diurnal fluctuations of ±3°C lowered infection rates and reduced spore burden compared to constant temperatures in our focal host Daphnia magna exposed to the microsporidium parasite Ordospora colligata. In contrast, a 3-day heatwave (+6°C) did not affect infection rates, but increased spore burden (relative to constant temperatures with the same mean) at 16°C, while reducing burden at higher temperatures. We conclude that changing patterns of climate variation, superimposed on shifts in mean temperatures due to global warming, may have profound and unanticipated effects on disease dynamics. Global warming is increasing average temperatures and causing extreme temperature fluctuations and heatwaves. These changes may affect when, where, and how often infectious disease outbreaks occur. This could have profound impacts on agriculture, human health, and wildlife. Studying how extreme temperatures or temperature fluctuations alter infections in laboratory animals may help scientists to better understand the impact of climate change on disease. A small aquatic invertebrate, such as a water flea, is one good candidate for such studies. These tiny creatures can be grown in small glass jars in temperature-controlled aquariums. Kunze, Luijckx et al. show that temperature fluctuations and heat waves have complex effects on parasitic infections in water fleas. In the experiments, water fleas housed with a parasite that infects them were exposed to constant temperatures, fluctuating temperatures, or three-day heatwaves, while being kept at a broad range of mean water temperatures. Then, Kunze, Luijckx et al. measured how these conditions affected the water fleas’ longevity, reproduction, and parasite infections. This revealed that temperature variations had a unique effect on the life span, and reproduction and infection rates of the water fleas, depending on the average water temperature the animals were kept at. Heatwaves drastically increased the number of parasites in the water fleas at an average water temperature of 16 °C but had no effect at all or decreased the number of parasites at 19 °C and 22 °C, respectively. Similarly, at high average water temperatures (>24 °C), temperature fluctuations reduced the number of water fleas infected with parasites and the number of parasites in each infected flea. Moreover, the maximum temperature at which parasites were able to cause infections was 5 °C lower under fluctuating temperatures than under constant temperatures. Kunze and Luijckx et al. show that consistent high temperatures, temperature changes, extreme weather events, and mean water temperature affect disease outcomes in water fleas. More studies are needed to assess how temperature variations change the course of diseases in other organisms and to understand the underlying mechanisms. Learning more about disease-temperature interactions will help scientists predict climate change-driven disease outbreaks.