Cultural practices perceived to be adaptive—from clearing land for food production to medical innovations—can disseminate quickly through human populations. However, these same practices often have unintended maladaptive effects. A particularly consequential effect is the emergence of diseases. In numerous instances, a cultural change is followed by the appearance of a new pathogen. Here, we develop mathematical models to analyze the population processes through which cultural evolution precipitates the emergence of a new disease. We find that when a risk-bearing cultural practice spreads, emergence can be an unavoidable cost even if a safer alternative practice eventually evolves from the original. Social learning and a fitness advantage associated with the evolving practice drive early disease emergence but the two factors have distinct effects on the time to mutation of the pathogen and significant stochastic variation is observed. For example, a disease can take longer to emerge in a population that adopts the risk-bearing practice quickly than in a population that is slow to transition. Extending the model to explore the effects of an alternative practice evolving from the original, we find a nonmonotonic relationship between relative risk of the two practices and the median time to disease emergence. Our findings contribute to understanding how cultural evolution can shape pathogen evolution and highlight the unpredictability of disease emergence.

中文翻译：

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文化创新如何引发新病原体的出现


从清理土地用于食品生产到医疗创新，被认为具有适应性的文化习俗可以在人群中迅速传播。然而，这些相同的做法往往会产生意想不到的适应不良影响。一个特别重要的影响是疾病的出现。在许多情况下，文化变化之后会出现新的病原体。在这里，我们开发了数学模型来分析文化进化导致新疾病出现的人口过程。我们发现，当一种承担风险的文化实践传播时，即使最终从原始实践演变出更安全的替代实践，出现也可能是不可避免的代价。与不断发展的实践相关的社会学习和健身优势推动了疾病的早期出现，但这两个因素对病原体突变的时间有不同的影响，并且观察到显着的随机变异。例如，与过渡缓慢的人群相比，在迅速采用承担风险做法的人群中，疾病可能需要更长的时间才能出现。扩展模型以探索从原始做法演变而来的替代做法的影响，我们发现两种做法的相对风险与疾病出现的中位时间之间存在非单调关系。我们的研究结果有助于理解文化进化如何塑造病原体进化并突出疾病出现的不可预测性。