University of California, Davis, School of Veterinary Medicine, 1320 Tupper Hall, Davis, California 95616, USA.
California Department of Fish and Wildlife, 1701 Nimbus Rd., Rancho Cordova, California 95670, USA.
J Wildl Dis. 2020 Jan;56(1):126-133. Epub 2019 Jul 11.
More than 460 cases of sarcoptic mange () in endangered San Joaquin kit foxes (SJKF; ) have been reported in Bakersfield, California, US. Because SJKF are a den-obligate species, their dens have been proposed as a route of transmission. We determined whether SJKF den temperatures and humidities could support mite off-host survival based on previously published estimates of off-host mite survival times. We monitored SJKF dens for 6 d in summer and winter of 2017 and 2018 using temperature- and humidity-sensing data loggers placed within the dens. Motion-triggered cameras monitored animal use of and entrances into the dens. Linear regression models were fitted to the published mite survival data to predict estimated mite survival time (EMST) in SJKF dens based on observed mean temperature and humidity of the den. Den covariates including irrigation, type of den, and season were then fitted to a mixed effects linear model to predict EMST. The average EMST across various habitats in Bakersfield was 4.8 d; the longest EMST was 7.1 d for dens in habitats with irrigated grass in the winter. Den climatic conditions in Bakersfield may support off-host mite survival through a timeframe adequate for revisitation by another fox. The finding that irrigation may enhance EMST suggested that risk to foxes varied with den type and that mitigation strategies may need to vary with den types.
在美国加利福尼亚州贝克斯菲尔德，已经报告了超过 460 例濒危圣华金狐（SJKF）的疥螨病（）病例。由于 SJKF 是一种穴居必需的物种，它们的洞穴被认为是传播途径。我们根据先前发表的关于螨虫离宿主存活时间的估计，确定了 SJKF 洞穴的温度和湿度是否能够支持螨虫离宿主存活。我们在 2017 年和 2018 年的夏季和冬季，使用放置在洞穴内的温度和湿度感应数据记录器，对 SJKF 洞穴进行了为期 6 天的监测。运动触发相机监测动物对洞穴的使用情况和进入洞穴的情况。我们根据观察到的洞穴平均温度和湿度，将线性回归模型拟合到已发表的螨虫存活数据中，以预测 SJKF 洞穴中的螨虫估计存活时间（EMST）。然后，将包括灌溉、洞穴类型和季节在内的洞穴协变量拟合到混合效应线性模型中，以预测 EMST。在贝克斯菲尔德的各种栖息地中，平均 EMST 为 4.8 天；在冬季有灌溉草地的栖息地中，最长的 EMST 为 7.1 天。贝克斯菲尔德的洞穴气候条件可能通过足够长的时间来支持螨虫的离宿主存活，足以让另一只狐狸再次来访。灌溉可能会延长 EMST 的发现表明，狐狸面临的风险因洞穴类型而异，缓解策略可能需要根据洞穴类型而有所不同。
