Data from: Temperature variability and moisture synergistically interact to exacerbate an epizootic disease

Climate change is altering global patterns of precipitation and temperature variability, with implications for parasitic diseases of humans and wildlife. A recent study confirmed predictions that increased temperature variability could exacerbate disease, because of lags in host acclimation following temperature shifts. However, the generality of these host acclimation effects and the potential for them to interact with other factors have yet to be tested. Here, we report similar effects of host thermal acclimation (constant versus shifted temperatures) on chytridiomycosis in red-spotted newts (Notophthalmus viridescens). Batrachochytrium dendrobatidis (Bd) growth on newts was greater following a shift to a new temperature, relative to newts already acclimated to this temperature (15°C versus 25°C). However, these acclimation effects depended on soil moisture (10, 16 and 21% water) and were only observed at the highest moisture level, which induced greatly increased Bd growth and infection-induced mortality. Acclimation effects were also greater following a decrease rather than an increase in temperature. The results are consistent with previous findings that chytridiomycosis is associated with precipitation, lower temperatures and increased temperature variability. This study highlights host acclimation as a potentially general mediator of climate–disease interactions, and the need to account for context-dependencies when testing for acclimation effects on disease.

气候变化正在改变全球降水与温度波动格局，对人类及野生生物的寄生性疾病产生重要影响。近期一项研究证实了此前的预测：由于温度变化后宿主适应性（host acclimation）存在滞后性，温度波动加剧可能会加重疾病进程。然而，这类宿主适应性效应的普遍性，以及其与其他因素产生交互作用的可能性，尚未得到验证。本研究报道了宿主热适应性（host thermal acclimation，即恒定温度与温度偏移处理）对红斑蝾螈（Notophthalmus viridescens）壶菌病（Chytridiomycosis）的相似影响。相较于已适应对应温度（15℃与25℃）的红斑蝾螈，温度发生改变后，蝾螈体表的蛙壶菌（Batrachochytrium dendrobatidis, Bd）增殖水平更高。但这类适应性效应依赖于土壤湿度（10%、16%与21%含水量），仅在最高湿度条件下才可观测到——该条件下蛙壶菌增殖水平与感染致死率均大幅升高。此外，温度降低时的适应性效应较温度升高时更为显著。本研究结果与此前结论一致，即壶菌病与降水、低温环境及温度波动加剧存在关联。本研究凸显出宿主适应性可作为气候-疾病交互作用的潜在通用调控因子，同时表明在检验宿主适应性对疾病的影响时，需考虑其情境依赖性。