Departamento de Ciencia Animal, Facultad de Ciencias Veterinarias, Universidad de Concepción, Chillán, Ñuble, Chile.
Instituto de Ciencias Ambientales Y Evolutivas, Universidad Austral de Chile, Valdivia, Chile.
Parasitol Res. 2022 Mar;121(3):1009-1020. doi: 10.1007/s00436-022-07452-4. Epub 2022 Feb 1.
Small mammals play an essential role as disseminators of pathogens because they reach high population densities and have ubiquitous distributions. In the Northern Hemisphere rodents are well recognized as reservoirs for tick-borne bacteria of the Anaplasmataceae family and also apicomplexan protozoans. In contrast, South American rodents hosting these microorganisms have been rarely identified. In this study, we collected blood from rodents and marsupials in northern Chile and screened for Anaplasmataceae bacteria and apicomplexan protozoa. Overall, 14.7% of the samples were positive for Babesia, Hepatozoon, and Sarcocystidae using conventional PCR assays targeting the structural 18S rRNA locus (18S). Phylogenetic analyses performed with amplicons derived from 18S and cytochrome c oxidase (COI) gene provided evidence of a Babesia sp. belonging to the Babesia microti group in Phyllotis darwini, and a novel Babesia genotype in P. darwini and Abrothrix jelskii. Furthermore, four novel genotypes of Hepatozoon retrieved from Abrothrix olivacea, P. darwini, and Oligoryzomys longicaudatus, formed independent lineages within a clade that includes additional Hepatozoon spp. detected in South American rodents. Moreover, an incidental finding of a previously detected apicomplexan, herein designated as Sarcocystidae sp., was recorded in Thylamys opossums with a high prevalence, indicating a possible specific association with these mammals. Phylogenetic analysis of Sarcoystidae sp. clearly demonstrated its relatedness to apicomplexans detected in Australian marsupials. Our results expand the range of mammals hosting tick-borne apicomplexans in South America, highlight a novel clade consisting of South American babesias, and report for the first time the B. microti group infecting rodents in the region.
小型哺乳动物作为病原体的传播者起着至关重要的作用，因为它们的种群密度很高，分布广泛。在北半球，啮齿动物被公认为蜱传立克次体科细菌和顶复门原生动物的宿主。相比之下，南美啮齿动物宿主携带这些微生物的情况很少被识别。在这项研究中，我们收集了智利北部的啮齿动物和有袋动物的血液，并对蜱传立克次体科细菌和顶复门原生动物进行了筛查。总体而言，使用针对结构 18S rRNA 基因座（18S）的常规 PCR 检测，14.7%的样本对巴贝虫、肝孢虫和肉孢子虫呈阳性。使用从 18S 和细胞色素 c 氧化酶（COI）基因获得的扩增子进行的系统发育分析为 Phyllotis darwini 中的巴贝虫属 sp. 属于微小巴贝虫组以及 P. darwini 和 Abrothrix jelskii 中的新型巴贝虫基因型提供了证据。此外，从 Abrothrix olivacea、P. darwini 和 Oligoryzomys longicaudatus 中获得的四种新型 Hepatozoon 基因型在包括在南美啮齿动物中检测到的其他 Hepatozoon spp. 的一个分支内形成独立的谱系。此外，在 Thylamys opossums 中偶然发现了先前检测到的一种顶复门，在此指定为肉孢子虫属 sp.，其流行率很高，表明与这些哺乳动物可能存在特定的关联。肉孢子虫属 sp. 的系统发育分析清楚地表明了它与在澳大利亚有袋动物中检测到的顶复门之间的亲缘关系。我们的研究结果扩大了南美洲携带蜱传顶复门的哺乳动物范围，突出了一个由南美巴贝斯虫组成的新型分支，并首次报告了该地区感染啮齿动物的微小巴贝斯虫组。
