RNA viruses in trypanosomatid parasites: a historical overview

Abstract

Viruses of trypanosomatids are now being extensively studied because of their diversity and the roles they play in flagellates' biology. Among the most prominent examples are leishmaniaviruses implicated in pathogenesis of Leishmania parasites. Here, we present a historical overview of this field, starting with early reports of virus-like particles on electron microphotographs, and culminating in detailed molecular descriptions of viruses obtained using modern next generation sequencing-based techniques. Because of their diversity, different life cycle strategies and host specificity, we believe that trypanosomatids are a fertile ground for further explorations to better understand viral evolution, routes of transitions, and molecular mechanisms of adaptation to different hosts.

Fig. 1. : described viruses of trypanosomatid in the context of RNA viruses’ diversity. Characterised representatives are highlighted and schematically depicted below the taxonomical summary. Asterisk marks the phylogenetic proximity, not the actual affiliation with the family.

Fig. 2. : genome organisation of LRV1/2 form various Leishmania spp. All leishmaniaviruses have two ORFs coding for capsid protein and RNA-dependent RNA polymerase (RDRP). The overlaps, putative secondary structures between the ORFs, and the reading frame of RDRP relative to capsid are indicated.