Vectors and Vector-borne Diseases Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
Vectors and Vector-borne Diseases Programme, Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa; Centre for Veterinary Wildlife Studies, Faculty of Veterinary Science, University of Pretoria, South Africa; National Zoological Garden, South African National Biodiversity Institute, P.O. Box 754, Pretoria, 0001, South Africa.
Vet Parasitol. 2021 Mar;291:109381. doi: 10.1016/j.vetpar.2021.109381. Epub 2021 Feb 14.
In sub-Saharan Africa, babesiosis in domestic dogs is caused primarily by Babesia rossi. Black-backed jackals (Canis mesomelas), which are subclinical carriers of B. rossi, were a likely reservoir host from which infection passed to domestic dogs. The role of other indigenous canids, e.g. African wild dogs (Lycaon pictus), as reservoirs of B. rossi has not been elucidated. The question also arises whether genetic differences have arisen between B. rossi infecting domestic dogs and "ancestral" B. rossi in jackals. In a previous study we found that nearly one-third (27 of 91) of jackals were infected with B. rossi; this was confirmed by 18S rDNA sequence analysis. In this study, the near full-length B. rossi 18S rRNA gene was successfully amplified from 6 domestic dogs and 3 black-backed jackals. The obtained recombinant sequences were identical (100 %) to previously described B. rossi sequences of black-backed jackals in South Africa, and 99 % similar to B. rossi from dogs in South Africa and the Sudan. Although blood specimens from 5 (10 %) of 52 free-ranging African wild dogs (from Kruger National Park, South Africa, reacted with the B. rossi probe on RLB hybridisation, the presence of B. rossi could not be confirmed by amplification and sequencing, nor by multiplex, real-time PCR. Although African wild dogs they can be infected with B. rossi without showing clinical signs, our findings suggest that they are apparently not important reservoir hosts of B. rossi.
在撒哈拉以南非洲，犬巴贝斯虫病主要由罗斯氏巴贝斯虫引起。黑背胡狼（Canis mesomelas）是罗斯氏巴贝斯虫的无症状携带者，可能是从它那里感染了家犬。其他土生土长的犬科动物，如非洲野犬（Lycaon pictus），是否是罗斯氏巴贝斯虫的储存宿主尚未阐明。还有一个问题是，感染家犬的罗斯氏巴贝斯虫与黑背胡狼中的“祖先”罗斯氏巴贝斯虫之间是否出现了遗传差异。在之前的一项研究中，我们发现近三分之一（91 只中的 27 只）的黑背胡狼感染了罗斯氏巴贝斯虫；这一点通过 18S rDNA 序列分析得到了证实。在这项研究中，我们成功地从 6 只家犬和 3 只黑背胡狼中扩增出了几乎全长的罗斯氏巴贝斯虫 18S rRNA 基因。获得的重组序列与南非黑背胡狼的先前描述的罗斯氏巴贝斯虫序列完全相同（100%），与南非和苏丹的犬类罗斯氏巴贝斯虫序列也有 99%的相似性。尽管 52 只自由放养的非洲野犬（来自南非克鲁格国家公园）的 5 份（10%）血液样本在 RLB 杂交时与罗斯氏巴贝斯虫探针反应，但通过扩增和测序以及多重实时 PCR 均无法确认罗斯氏巴贝斯虫的存在。尽管非洲野犬可能感染了罗斯氏巴贝斯虫而没有表现出临床症状，但我们的研究结果表明，它们显然不是罗斯氏巴贝斯虫的重要储存宿主。
