Laboratory of Tripanosomatid Biology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil.
PLoS Negl Trop Dis. 2010 Feb 2;4(2):e589. doi: 10.1371/journal.pntd.0000589.
The importance of the genus Thrichomys in the retention of infection and transmission of Leishmania species is supported by previous studies that describe an ancient interaction between caviomorphs and trypanosomatids and report the natural infection of Thrichomys spp. Moreover, these rodents are widely dispersed in Brazil and recognized as important hosts of other tripanosomatids. Our main purpose was to evaluate the putative role of Thrichomys laurentius in the retention of infection and amplification of the transmission cycle of Leishmania infantum and L. braziliensis. Male and female T. laurentius (n = 24) born in captivity were evaluated for the retention of infection with these Leishmania species and followed up by parasitological, serological, hematological, biochemical, histological, and molecular assays for 3, 6, 9, or 12 months post infection (mpi). T. laurentius showed its competence as maintenance host for the two inoculated Leishmania species. Four aspects should be highlighted: (i) re-isolation of parasites 12 mpi; (ii) the low parasitic burden displayed by T. laurentius tissues; (iii) the early onset and maintenance of humoral response, and (iv) the similar pattern of infection by the two Leishmania species. Both Leishmania species demonstrated the ability to invade and maintain itself in viscera and skin of T. laurentius, and no rodent displayed any lesion, histological changes, or clinical evidence of infection. We also wish to point out the irrelevance of the adjective dermotropic or viscerotropic to qualify L. braziliensis and L. infantum, respectively, when these species are hosted by nonhuman hosts. Our data suggest that T. laurentius may act at least as a maintenance host of both tested Leishmania species since it maintained long-lasting infections. Moreover, it cannot be discarded that Leishmania spp. infection in free-ranging T. laurentius could result in higher parasite burden due the more stressing conditions in the wild. Therefore the tissular parasitism of the skin, infectiveness to the vector, and amplification of the transmission cycle of both Leishmania species could be expected.
属 Trichomys 在保留感染和传播利什曼原虫物种方面的重要性得到了先前研究的支持，这些研究描述了有袋目动物和原生动物之间的古老相互作用，并报告了 Trichomys spp. 的自然感染。此外，这些啮齿动物广泛分布在巴西，并被认为是其他原生动物的重要宿主。我们的主要目的是评估 Laurentius 属 Trichomys 在保留感染和放大利什曼原虫婴儿和 L. braziliensis 传播周期方面的作用。在圈养中出生的雄性和雌性 T. laurentius（n = 24）被评估是否保留了这些利什曼原虫物种的感染，并通过寄生虫学、血清学、血液学、生化学、组织学和分子检测进行了 3、6、9 或 12 个月的感染后监测（mpi）。T. laurentius 显示出它是两种接种利什曼原虫的维持宿主的能力。有四个方面值得强调：（i）12 mpi 时寄生虫的重新分离；（ii）T. laurentius 组织中的寄生虫负担低；（iii）体液反应的早期发生和维持；以及（iv）两种利什曼原虫的感染模式相似。两种利什曼原虫都表现出入侵和维持自身在 T. laurentius 内脏和皮肤中的能力，并且没有啮齿动物显示出任何病变、组织学变化或感染的临床证据。我们还希望指出，当这些物种被非人类宿主宿主时，形容词 dermotropic 或 viscerotropic 用于分别描述 L. braziliensis 和 L. infantum 是不相关的。我们的数据表明，T. laurentius 可能至少充当了两种测试利什曼原虫的维持宿主，因为它维持了持久的感染。此外，由于野外条件更为紧迫，在自由放养的 T. laurentius 中感染利什曼原虫可能会导致更高的寄生虫负担，这一点不能排除。因此，可以预期两种利什曼原虫的皮肤组织寄生虫病、对媒介的传染性和传播周期的放大。
