McFarland Richard, Henzi S Peter, Barrett Louise, Bonnell Tyler, Fuller Andrea, Young Christopher, Hetem Robyn S
NTU Psychology, Nottingham Trent University, Nottingham NG1 4FQ, United Kingdom;
Brain Function Research Group, School of Physiology, Faculty of Health Science, University of the Witwatersrand, Johannesburg 2193, South Africa.
Proc Natl Acad Sci U S A. 2021 Nov 2;118(44). doi: 10.1073/pnas.2107881118.
Fevers are considered an adaptive response by the host to infection. For gregarious animals, however, fever and the associated sickness behaviors may signal a temporary loss of capacity, offering other group members competitive opportunities. We implanted wild vervet monkeys () with miniature data loggers to obtain continuous measurements of core body temperature. We detected 128 fevers in 43 monkeys, totaling 776 fever-days over a 6-year period. Fevers were characterized by a persistent elevation in mean and minimum 24-h body temperature of at least 0.5 °C. Corresponding behavioral data indicated that febrile monkeys spent more time resting and less time feeding, consistent with the known sickness behaviors of lethargy and anorexia, respectively. We found no evidence that fevers influenced the time individuals spent socializing with conspecifics, suggesting social transmission of infection within a group is likely. Notably, febrile monkeys were targeted with twice as much aggression from their conspecifics and were six times more likely to become injured compared to afebrile monkeys. Our results suggest that sickness behavior, together with its agonistic consequences, can carry meaningful costs for highly gregarious mammals. The degree to which social factors modulate the welfare of infected animals is an important aspect to consider when attempting to understand the ecological implications of disease.
发热被认为是宿主对感染的一种适应性反应。然而，对于群居动物来说，发热及相关的疾病行为可能预示着暂时的能力丧失，从而为其他群体成员提供了竞争机会。我们给野生黑长尾猴植入了微型数据记录器，以持续测量核心体温。在6年时间里，我们在43只猴子身上检测到128次发热，总计776个发热日。发热的特征是24小时平均体温和最低体温持续升高至少0.5°C。相应的行为数据表明，发热的猴子休息时间更长，进食时间更少，这分别与已知的嗜睡和厌食等疾病行为一致。我们没有发现证据表明发热会影响个体与同种动物社交的时间，这表明群体内感染的社交传播很可能发生。值得注意的是，与未发热的猴子相比，发热的猴子受到同种动物攻击的次数是未发热猴子的两倍，受伤的可能性是未发热猴子的六倍。我们的研究结果表明，疾病行为及其争斗后果会给高度群居的哺乳动物带来重大代价。在试图理解疾病的生态影响时，社会因素调节受感染动物福利的程度是一个需要考虑的重要方面。
