Conservation Medicine, Facultad de Ciencias de la Vida, Universidad Andres Bello, República 252, Santiago, Chile.
Facultad de Ciencias de la Vida, Universidad Andres Bello, República 440, Santiago, Chile; Department of Animal Health. NEIKER-Basque Institute for Agricultural Research and Development. Basque Research and Technology Alliance (BRTA). Parque Científico y Tecnológico de Bizkaia, P812, 48160 Derio, Spain.
Ticks Tick Borne Dis. 2021 Sep;12(5):101752. doi: 10.1016/j.ttbdis.2021.101752. Epub 2021 Jun 4.
Anaplasma platys and Ehrlichia canis are members of the Anaplasmataceae family that cause disease in dogs and are mainly transmitted by Rhipicephalus sanguineus species group ticks. We performed a cross-sectional study on these pathogens across six bioclimatic regions of Chile, including 719 free-ranging rural dogs, 132 Andean foxes (Lycalopex culpaeus), and 82 South American gray foxes (Lycalopex griseus). Dog and fox blood samples were first screened for DNA of Anaplasmataceae followed by two Ehrlichia-specific protocols. Antibodies against Anaplasma sp. and E. canis were assessed by immunofluorescence in dogs. Ectoparasites were collected and identified, with the determination of the lineages of the Rhipicephalus sanguineus species group by molecular and phylogenetic analyses. Finally, potential risk factors for infection were investigated across the different bioclimatic regions and host species. All DNA amplicons obtained from the screening protocol corresponded to Anaplasma platys. The occurrence of both A. platys DNA and antibodies was confirmed in all six bioclimatic regions, except for regions at high altitude and/or without either R. sanguineus species group lineage present. Dogs infested with R. sanguineus ticks were significantly more prone to be infected and exposed to Anaplasma spp. Prevalence of DNA was significantly higher in juvenile (19%) than in adult dogs (9%), whereas the opposite was found for seroprevalence (19% versus 35%, respectively). Overall prevalence of A. platys DNA was higher in dogs (11%) than in foxes (4%), probably owing to markedly lower tick infestations in the foxes. Ehrlichia canis DNA was not detected in any sample, and antibodies against this pathogen were detected only in four dogs, in areas with both R. sanguineus lineages present. Free-ranging dogs in Chile could be favoring the maintenance of A. platys in all areas suitable for its tick vector. Although apparently infrequent, spillovers from dogs to foxes may be taking place and should be considered in management plans in Chile.
平角阿托波菌和犬埃立克体是立克次体科的成员，它们会导致犬类患病，主要通过扇头蜱属的蜱传播。我们在智利的六个生物气候区进行了这些病原体的横断面研究，包括 719 只自由放养的农村犬、132 只安第斯狐（Lycalopex culpaeus）和 82 只南美灰狐（Lycalopex griseus）。首先对犬和狐的血液样本进行了针对立克次体科的 DNA 筛查，然后进行了两种特定的埃立克体协议。通过犬的免疫荧光法评估了针对阿氏普氏菌和犬埃立克体的抗体。收集并鉴定了外寄生虫，并通过分子和系统发育分析确定了扇头蜱属的谱系。最后，在不同的生物气候区和宿主物种中调查了潜在的感染危险因素。从筛选方案获得的所有 DNA 扩增子均与平角阿托波菌相对应。除了高海拔和/或没有扇头蜱属的任何谱系的地区外，在所有六个生物气候区都确认了 A. platys DNA 的发生和抗体的存在。感染了扇头蜱属蜱的犬更有可能受到感染并暴露于阿氏普氏菌。在幼龄犬（19%）中，DNA 的流行率明显高于成年犬（9%），而在血清流行率方面则相反（分别为 19%和 35%）。在犬中，A. platys DNA 的总流行率（11%）高于狐（4%），这可能是由于狐中蜱的感染明显较少。在任何样本中均未检测到犬埃立克体 DNA，并且仅在存在两种扇头蜱属谱系的地区的四只犬中检测到针对该病原体的抗体。智利的自由放养犬可能在所有适合其蜱传播媒介的地区都有利于平角阿托波菌的维持。尽管明显不常见，但犬向狐的溢出可能正在发生，在智利的管理计划中应考虑到这一点。
