Data from: Stress hormones predict a host superspreader phenotype in the West Nile virus system

Glucocorticoid stress hormones, such as corticosterone (CORT), have
profound effects on the behaviour and physiology of organisms, and thus
have the potential to alter host competence and the contributions of
individuals to population- and community-level pathogen dynamics. For
example, CORT could alter the rate of contacts among hosts, pathogens and
vectors through its widespread effects on host metabolism and activity
levels. CORT could also affect the intensity and duration of pathogen
shedding and risk of host mortality during infection. We experimentally
manipulated songbird CORT, asking how CORT affected behavioural and
physiological responses to a standardized West Nile virus (WNV) challenge.
Although all birds became infected after exposure to the virus, only birds
with elevated CORT had viral loads at or above the infectious threshold.
Moreover, though the rate of mortality was faster in birds with elevated
CORT compared with controls, most hosts with elevated CORT survived past
the day of peak infectiousness. CORT concentrations just prior to
inoculation with WNV and anti-inflammatory cytokine concentrations
following viral exposure were predictive of individual duration of
infectiousness and the ability to maintain physical performance during
infection (i.e. tolerance), revealing putative biomarkers of competence.
Collectively, our results suggest that glucocorticoid stress hormones
could directly and indirectly mediate the spread of pathogens.

糖皮质激素应激激素（如皮质酮（CORT））对生物体的行为与生理机能具有深远调控作用，进而可改变宿主传播能力以及个体在种群和群落层面的病原体动态中的贡献。例如，皮质酮可通过广泛调控宿主代谢与活动水平，改变宿主、病原体与媒介之间的接触速率。此外，皮质酮还可影响感染期间病原体的排毒强度与持续时长，以及宿主的感染死亡风险。本研究通过实验操控鸣禽体内的皮质酮水平，探究皮质酮对标准化西尼罗河病毒（West Nile Virus, WNV）攻毒试验后行为与生理响应的影响。尽管所有受试鸣禽在病毒暴露后均发生感染，但仅皮质酮水平升高的个体，其病毒载量达到或超过了传染性阈值。此外，相较于对照组，皮质酮水平升高的鸣禽死亡速率更快，但此类宿主中的绝大多数均存活至传染性峰值日之后。西尼罗河病毒接种前的皮质酮浓度，以及病毒暴露后的抗炎细胞因子浓度，可预测个体的感染持续时长以及感染期间维持身体机能的能力（即感染耐受能力），这一发现揭示了宿主传播能力的潜在生物标志物。综合来看，本研究结果表明，糖皮质激素应激激素可通过直接与间接途径介导病原体的传播扩散。