Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Departamento de Medicina Preventiva, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Int J Parasitol. 2021 Nov;51(12):1047-1057. doi: 10.1016/j.ijpara.2021.05.009. Epub 2021 Jul 27.
Leishmania (Leishmania) major is an important agent of cutaneous leishmaniasis, having as a vector sandflies belonging to the genus Phlebotomus. Although this species has been described as restricted to the Old World, parasites similar to L. major have been isolated from South American patients who have never travelled abroad. These parasites were named "L. major-like", and several studies have been carried out to characterise them biochemically, molecularly, and biologically. However, the phylogenetic origin of these isolates is still unknown. In the present study we characterised three L. major-like isolates, named BH49, BH121 and BH129, using comparative genomics approaches. We evaluated the presence of gene and segmental duplications/deletions and the presence of aneuploidies that could explain the differences in infectivity observed in the BH49 and BH121 isolates. All isolates presented a pattern of mosaic aneuploidy and gene copy number variation, which are common in the genus Leishmania. Virulence factors such as phosphatases and peptidases were found to have increased gene copy numbers in the infective isolate, which could explain the difference in infectivity previously observed between BH121 and BH49. Phylogenetic analyses revealed that BH49, BH121 and BH129 L. major-like grouped with L. major isolates, and suggest they were imported from the Old World in at least two independent events. We suggest that new epidemiological inquiries should also evaluate L. major infections in South America, to assess the epidemiological importance of this species in the New World.
利什曼原虫（Leishmania）是皮肤利什曼病的重要病原体，其传播媒介为属于白蛉属的沙蝇。尽管该物种被描述为仅限于旧世界，但从未出过国的南美患者身上分离出的寄生虫与利什曼原虫类似。这些寄生虫被命名为“利什曼原虫样”，已经进行了多项研究来对它们进行生物化学、分子和生物学特征分析。然而，这些分离株的系统发育起源仍然未知。在本研究中，我们使用比较基因组学方法对三种名为 BH49、BH121 和 BH129 的利什曼原虫样分离株进行了特征描述。我们评估了基因和片段重复/缺失的存在情况，以及是否存在非整倍性，以解释在 BH49 和 BH121 分离株中观察到的感染性差异。所有分离株均表现出镶嵌性非整倍体和基因拷贝数变异，这在利什曼属中很常见。发现毒力因子如磷酸酶和肽酶的基因拷贝数增加，这可以解释之前在 BH121 和 BH49 之间观察到的感染性差异。系统发育分析表明，BH49、BH121 和 BH129 的利什曼原虫样与利什曼原虫分离株聚在一起，表明它们至少是从旧世界两次独立传入的。我们建议，新的流行病学调查还应评估南美的利什曼原虫感染情况，以评估该物种在新世界的流行病学重要性。
