University of California-Davis, School of Veterinary Medicine, Department of Medicine and Epidemiology, 1275 Med Science Dr., Davis, California 95616, USA.
Laboratorio de Ecología de Enfermedades y Una Salud, Departamento de Etología, Fauna Silvestre y Animales de Laboratorio, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Ciudad Universitaria, Av. Universidad no. 3000, Coyoacán 04510 Ciudad de México, Mexico.
J Wildl Dis. 2023 Oct 1;59(4):722-733. doi: 10.7589/JWD-D-22-00179.
Rocky Mountain spotted fever (RMSF), caused by the bacterium Rickettsia rickettsii, is a re-emerging tick-borne zoonosis in North America, with hundreds of human fatalities in multiple outbreaks in northern Mexico and the southwestern US in the past few decades. Free-roaming dogs are key because they are reservoirs for the pathogen and the main hosts of the brown dog tick (Rhipicephalus sanguineus), which vectors RMSF in this region. Because coyotes (Canis latrans) can be infected with R. rickettsii and infested with Rh. sanguineus, we hypothesized that space sharing among dogs and coyotes could enhance disease risks. In summer 2021, we captured and sampled 11 coyotes at two sites in Baja California, Mexico, near population centers with human cases of RMSF, and fitted seven individuals with GPS logging collars. We also tested tissue samples, sera, and ectoparasites for DNA of R. rickettsii with PCR and used serology to detect antibodies to R. rickettsii. Finally, we deployed an array of cameras to document dog-coyote interactions. Mean home range size was 40.37 km2. Both GPS and camera data showed considerable home range overlap both between individual coyotes and between coyotes and dogs. Coyotes were active in areas where dogs occur including the domestic interface surrounding human settlements. Although none of our samples were positive for R. rickettsii on PCR, 72.7% (8/11) of the samples were seropositive with titers ≥64. Our data confirm shared space use and risk of shared parasites and disease between coyotes and dogs.
落矶山斑点热（RMSF）由立克次体细菌（Rickettsia rickettsii）引起，是北美重新出现的蜱传动物传染病，在过去几十年中，墨西哥北部和美国西南部的多次暴发中，有数百人死亡。自由放养的狗是关键，因为它们是病原体的储存宿主，也是该地区传播 RMSF 的褐狗蜱（Rhipicephalus sanguineus）的主要宿主。由于郊狼（Canis latrans）可能感染立克次体细菌并被褐狗蜱寄生，我们假设狗和郊狼之间的空间共享可能会增加疾病风险。2021 年夏天，我们在墨西哥下加利福尼亚的两个地点捕获并采样了 11 只郊狼，这两个地点靠近有 RMSF 人类病例的人口中心，并为 7 只个体佩戴了 GPS 记录项圈。我们还测试了组织样本、血清和外寄生虫的立克次体细菌 DNA，并用血清学检测抗立克次体细菌的抗体。最后，我们部署了一系列摄像头来记录狗-郊狼的互动。平均家域大小为 40.37 平方公里。GPS 和摄像头数据都显示，个体郊狼之间以及郊狼和狗之间的家域重叠相当大。郊狼在狗出没的区域活动，包括人类住区周围的家庭界面。尽管我们的样本中没有一个通过 PCR 对立克次体细菌呈阳性，但 72.7%（8/11）的样本血清学阳性，滴度≥64。我们的数据证实了郊狼和狗之间共享空间使用和共享寄生虫和疾病的风险。
