Dipartimento di Sanità Pubblica e Zootecnia, Università degli Studi di Bari, Valenzano, BA, Italy.
Exp Parasitol. 2010 Jun;125(2):184-5. doi: 10.1016/j.exppara.2010.02.003. Epub 2010 Feb 6.
Phlebotomine sand flies are the only proven biological vectors of Leishmania parasites. However, Rhipicephalus sanguineus ticks have long been suspected to transmit Leishmania infantum in studies carried out in laboratory and natural conditions. In the present study, 5 microl of L. infantum promastigotes (1x10(6) cells per ml) was injected into the hemocel through the coxa I of four engorged females (F1, F2, F3 and F4). Control ticks (F5 and F6) were injected with sterile phosphate-buffered saline (PBS) using the same procedure. Then, these females, their eggs, and the originated larvae were tested by real time polymerase chain reaction (real-time PCR) for the presence of L. infantum kinetoplast DNA (kDNA). Females and eggs were tested after the end of the oviposition period (about 5 weeks post-inoculation) whereas larvae were tested about 4 months after the inoculation of females. All artificially infected females were positive for L. infantum kDNA. In addition, two pools of eggs (one from F2 and other from F4) and four pools of larvae (one from each F1 and F4 and two from F2) were positive for L. infantum kDNA. These results showed, for the first time, the transovarial passage of L. infantum kDNA in R. sanguineus ticks, thus suggesting that the transovarial transmission of L. infantum protozoa in ticks is worth to be investigated.
白蛉是唯一被证实的利什曼原虫寄生虫的生物传播媒介。然而，在实验室和自然条件下进行的研究长期以来一直怀疑硬蜱传播利什曼原虫婴儿。在本研究中，将 5 微升的利什曼原虫前鞭毛体（每毫升 1x10(6)个细胞）通过 coxa I 注入到四只饱血的雌性（F1、F2、F3 和 F4）中。用相同的程序，对照硬蜱（F5 和 F6）注入无菌磷酸盐缓冲盐水（PBS）。然后，通过实时聚合酶链反应（real-time PCR）检测这些雌性、它们的卵和起源幼虫中是否存在利什曼原虫动基体 DNA（kDNA）。在产卵期结束后（接种后约 5 周）检测雌性和卵，而在接种雌性大约 4 个月后检测幼虫。所有人工感染的雌性均为利什曼原虫 kDNA 阳性。此外，两个卵池（一个来自 F2，另一个来自 F4）和四个幼虫池（一个来自 F1 和 F4，两个来自 F2）均为利什曼原虫 kDNA 阳性。这些结果首次表明利什曼原虫 kDNA 在硬蜱中经卵传递，这表明利什曼原虫原生动物在硬蜱中的经卵传播值得进一步研究。
