Sukla Soumi, Roy Syamal, Sundar Shyam, Biswas Subhajit
Indian Institute of Chemical Biology (CSIR), Kolkata, West Bengal, 700032, India.
Cooch Behar Panchanan Barma University, Cooch Behar, West Bengal, 736101, India.
Arch Virol. 2017 Dec;162(12):3827-3835. doi: 10.1007/s00705-017-3559-y. Epub 2017 Sep 22.
The great majority of kala-azar/visceral leishmaniasis (VL) cases, which are caused by Leishmania donovani (LD), are reported in Asia. We investigated whether leishmaniaviruses (LRVs) are present in LD isolates. These dsRNA viruses contribute to hyperpathogenicity, as observed in the case of other members of the genus Leishmania. However, LRVs could not be detected in 22 Indian LD isolates tested in the present study, while 70% of these original LD isolates harboured a virus that was not of LD but instead of Leptomonas seymouri (LS) origin. LS is another protozoon that parasitizes the sandfly vector of LD. Historically, LD clinical isolates from India often showed high incidence of LS coinfection. LS was detected in 20 out of the 22 (91%) above-mentioned LD isolates. Leptomonas seymouri narna-like virus 1 (Lepsey NLV1) was identified by whole-genome sequencing in an LD-LS coinfected sample, and its presence was confirmed by PCR and sequencing in 15 (75%) of the 20 LD-LS coinfected samples. The LS-negative LD samples were also virus negative by PCR. That the human host is exposed to an RNA virus in LS, another coinfecting parasite with LD, i.e., the "LD-LS-Lepsey NLV1 triple pathogen" phenomenon, unveils a new paradigm of research towards revisiting the mysteries of Indian leishmaniasis pathogenesis and management.
绝大多数由杜氏利什曼原虫（LD）引起的黑热病/内脏利什曼病（VL）病例报告于亚洲。我们调查了LD分离株中是否存在利什曼病毒（LRV）。这些双链RNA病毒会导致超致病性，正如在利什曼原虫属的其他成员中所观察到的那样。然而，在本研究中检测的22株印度LD分离株中未检测到LRV，而这些原始LD分离株中有70%携带一种并非来自LD而是来自西氏细滴虫（LS）的病毒。LS是另一种寄生于LD白蛉传播媒介的原生动物。从历史上看，来自印度的LD临床分离株常显示出较高的LS共感染发生率。在上述22株LD分离株中有20株（91%）检测到了LS。通过全基因组测序在一个LD-LS共感染样本中鉴定出西氏细滴虫类纳RNA病毒1（Lepsey NLV1），并通过PCR和测序在20个LD-LS共感染样本中的15个（75%）中证实了其存在。LS阴性的LD样本通过PCR检测也为病毒阴性。人类宿主暴露于LS中的一种RNA病毒，即另一种与LD共感染的寄生虫，也就是“LD-LS-Lepsey NLV1三重病原体”现象，揭示了重新审视印度利什曼病发病机制和管理奥秘的一种新的研究范式。
