Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, CO, 80523, USA; National Wildlife Research Center, United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, 4101 Laporte Avenue, Fort Collins, CO, 80521, USA.
Wildlife Ecology and Conservation, Range Cattle Research and Education Center, University of Florida, 3401 Experiment Station, Ona, FL, 33865, USA.
Prev Vet Med. 2021 Sep;194:105423. doi: 10.1016/j.prevetmed.2021.105423. Epub 2021 Jul 3.
Little is known about disease transmission relevant contact rates at the wildlife-livestock interface and the factors shaping them. Indirect contact via shared resources is thought to be important but remains unquantified in most systems, making it challenging to evaluate the impact of livestock management practices on contact networks. Free-ranging wild pigs (Sus scrofa) in North America are an invasive, socially-structured species with an expanding distribution that pose a threat to livestock health given their potential to transmit numerous livestock diseases, such as pseudorabies, brucellosis, trichinellosis, and echinococcosis, among many others. Our objective in this study was to quantify the spatial variations in direct and indirect contact rates among wild pigs and cattle on a commercial cow-calf operation in Florida, USA. Using GPS data from 20 wild pigs and 11 cattle and a continuous-time movement model, we extracted three types of spatial contacts between wild pigs and cattle, including direct contact, indirect contact in the pastoral environment (unknown naturally occurring resources), and indirect contact via anthropogenic cattle resources (feed supplements and water supply troughs). We examined the effects of sex, spatial proximity, and cattle supplement availability on contact rates at the species level and characterized wild pig usage of cattle supplements. Our results suggested daily pig-cattle direct contacts occurred only occasionally, while a significant number of pig-cattle indirect contacts occurred via natural resources distributed heterogeneously across the landscape. At cattle supplements, more indirect contacts occurred at liquid molasses than water troughs or molasses-mineral block tubs due to higher visitation rates by wild pigs. Our results can be directly used for parameterizing epidemiological models to inform risk assessment and optimal control strategies for controlling transmission of shared diseases.
关于野生动物与牲畜接触界面的疾病传播相关接触率及其影响因素，人们知之甚少。人们认为，通过共享资源的间接接触很重要，但在大多数系统中尚未量化，这使得评估牲畜管理实践对接触网络的影响具有挑战性。北美的野猪（Sus scrofa）是一种具有社会结构的入侵物种，分布范围不断扩大，由于其具有传播多种牲畜疾病的潜力，如伪狂犬病、布鲁氏菌病、旋毛虫病和棘球蚴病等，对牲畜健康构成威胁。本研究的目的是量化美国佛罗里达州一个商业奶牛场中野猪和牛之间直接和间接接触率的空间变化。我们利用 20 头野猪和 11 头牛的 GPS 数据和连续时间移动模型，提取了野猪和牛之间三种类型的空间接触，包括直接接触、牧场环境中的间接接触（未知的自然发生资源）和通过人为的牛资源（饲料补充剂和水供应槽）产生的间接接触。我们检验了性别、空间接近度和牛补充剂供应对物种水平接触率的影响，并描述了野猪对牛补充剂的使用情况。结果表明，猪牛之间的直接接触每天仅偶尔发生，而通过分布在景观中不均匀的自然资源发生的大量猪牛之间的间接接触。在牛补充剂方面，由于野猪的访问率更高，液态糖蜜比水槽或糖蜜矿物块槽产生更多的间接接触。我们的研究结果可直接用于为流行病学模型提供参数，以告知共享疾病传播的风险评估和最佳控制策略。
