Global Health and Tropical Medicine (GHMT), Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa (NOVA), 1349-008 Lisboa, Portugal; Medical Parasitology Unit, IHMT/NOVA, 1349-008 Lisbon, Portugal.
Global Health and Tropical Medicine (GHMT), Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa (NOVA), 1349-008 Lisboa, Portugal; Medical Microbiology Unit, IHMT/NOVA, 1349-008 Lisbon, Portugal.
Infect Genet Evol. 2020 Jan;77:104069. doi: 10.1016/j.meegid.2019.104069. Epub 2019 Oct 25.
Cats have been found infected by the same Leishmania species that also infect dogs and humans in both the New and Old Worlds, and their role as additional reservoir hosts of L. infantum has been previously suggested. Currently, the genetic diversity of Leishmania spp. detected in cats is poorly understood. In this cross-sectional study, the partial nucleotide sequences of four gene markers (cytB, g6pdh, hsp70 and ITS-rDNA) were explored to investigate the genetic diversity and the phylogenetic relationships of Leishmania parasites detected in cats. A total of 25 cat buffy coat samples where the presence of Leishmania SSU-rDNA was revealed by PCR (from a convenience sample of 465 cats screened), as well as six Leishmania strains previously isolated from cats, were included in this study. Phylogenetic analyses showed that the majority of Leishmania parasites detected in cats did not display distinctive genetic features, sharing the same genetic types with L. infantum strains isolated from humans, dogs and phlebotomine sand flies. Unexpectedly, DNA of L. major and/or of a L. major/L. donovani sensu lato hybrid was detected in buffy coat samples of two cats from different regions of Portugal. However, a mix infection hypothesis cannot be formally excluded. To our knowledge, this study represents the first evidence for the presence of DNA of Leishmania hybrid parasites in cats. The results reported here not only reinforce the idea that cats play a role in the epidemiology of zoonotic leishmaniosis but also indicate the circulation of L. major and/or L. major/L. donovani s.l. hybrid parasites in Portugal. Also, whenever sequencing of whole Leishmania genomes regularly cannot be accomplished, and while their complete genomes remain under-represented in the nucleotide sequence databases, the combined use of multiple genetic markers, including kinetoplast maxicircle DNA, seems to be essential for typing of Leishmania parasites.
猫已被发现感染了与新世界和旧世界的狗和人类相同的利什曼原虫物种，并且先前已经提出了它们作为利什曼原虫感染的额外储存宿主的作用。目前，猫中检测到的利什曼原虫 spp 的遗传多样性。在这项横断面研究中，探索了四个基因标记（细胞色素 B、g6pdh、hsp70 和 ITS-rDNA）的部分核苷酸序列，以调查猫中检测到的利什曼原虫寄生虫的遗传多样性和系统发育关系。总共包括 25 只猫的缓冲涂层样本，这些样本通过 PCR 显示存在利什曼原虫 SSU-rDNA（从 465 只筛选的猫中进行的方便样本），以及之前从猫中分离出的六种利什曼原虫菌株，包括在这项研究中。系统发育分析表明，在猫中检测到的大多数利什曼原虫寄生虫没有表现出独特的遗传特征，与从人类、狗和白蛉沙蝇中分离出的利什曼原虫感染株具有相同的遗传类型。出乎意料的是，在来自葡萄牙不同地区的两只猫的缓冲涂层样本中检测到了 DNA 利什曼原虫和/或利什曼原虫/利什曼原虫混合种。然而，不能正式排除混合感染的假设。据我们所知，这项研究首次证明了猫中存在利什曼原虫混合寄生虫的 DNA。这里报道的结果不仅加强了猫在人畜共患利什曼病流行病学中发挥作用的观点，而且还表明了利什曼原虫和/或利什曼原虫/利什曼原虫混合种在葡萄牙的循环。此外，只要不能定期完成整个利什曼原虫基因组的测序，并且其完整基因组在核苷酸序列数据库中仍然代表性不足时，包括动质体最大环 DNA 在内的多种遗传标记的联合使用似乎对于利什曼原虫寄生虫的分型至关重要。
