Abstract Heterogeneity of infectious disease transmission can be generated by individual differences in the frequency of contacts with susceptible individuals, in the ability to transmit the infectious agent or in the duration of infection, and by spatial variation in the distribution, density or movements of hosts. Identifying spatial and individual heterogeneity can help improving management strategies to eradicate or mitigate infectious diseases, by targeting the individuals or areas that are responsible for most transmissions. Individual-based models allow quantifying the respective role of these sources of heterogeneity by integrating potential mechanisms that generate heterogeneity and then by tracking transmissions caused by each infected individual. In this study, we provide an individual-based model of endemic brucellosis Brucella melitensis transmission in the population of Alpine ibex (Capra ibex) of the Bargy massif (France) by taking advantage of detailed information available on ibex population dynamics, behaviour, and habitat use, and on epidemiological surveys. This host-pathogen system is expected to be subject of both individual and spatial heterogeneity. We first estimated the transmission probabilities, hitherto unknown, of the two main transmission routes of the infection (i.e., exposure to infectious births/abortions and venereal transmission). Then, we quantified heterogeneity at both individual and spatial levels. We found that both transmission routes are not negligible to explain the data, and that there is a high amount of heterogeneity of the host-pathogen system at the individual level, with females generating around 90% of the new cases of brucellosis infection. Males transmit infection at a lesser extent but still play a non-negligible role because they move between subpopulations and thereby create opportunities for spreading the infection spatially by venereal transmission. Two particular socio-spatial units are hotspots of transmission, and act as sources of transmission for the other units. These results may have important implications for disease management strategies.

中文翻译：

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评估高山野山羊布鲁氏菌传播空间和个体异质性的基于个体的模型

摘要 传染病传播的异质性可以由与易感个体接触的频率、传染性病原体的传播能力或感染持续时间的个体差异以及宿主分布、密度或运动的空间变化产生。确定空间和个体的异质性有助于改进管理策略，以消除或减轻传染病的影响，将目标锁定在对大多数传播负责的个人或地区。基于个体的模型允许通过整合产生异质性的潜在机制，然后通过跟踪每个受感染个体引起的传播来量化这些异质性来源的各自作用。在这项研究中，我们利用有关 ibex 种群动态、行为和栖息地使用的详细信息，提供了一个基于个体的地方性布鲁氏菌病布鲁氏菌在 Bargy 地块（法国）的高山野山羊（Capra ibex）种群中传播的模型流行病学调查。预计这种宿主-病原体系统会受到个体和空间异质性的影响。我们首先估计了迄今为止未知的两种主要感染传播途径（即，接触传染性出生/流产和性病传播）的传播概率。然后，我们量化了个体和空间层面的异质性。我们发现这两种传播途径对于解释数据都不可忽视，并且宿主-病原体系统在个体水平上存在很大的异质性，大约 90% 的布鲁氏菌感染新病例是由女性产生的。男性传播感染的程度较小，但仍然发挥着不可忽视的作用，因为它们在亚群之间移动，从而为通过性病传播在空间上传播感染创造了机会。两个特定的社会空间单位是传播热点，并作为其他单位的传播源。这些结果可能对疾病管理策略具有重要意义。两个特定的社会空间单位是传播热点，并作为其他单位的传播源。这些结果可能对疾病管理策略具有重要意义。两个特定的社会空间单位是传播热点，并作为其他单位的传播源。这些结果可能对疾病管理策略具有重要意义。