Leishmaniavirus Explained

Leishmaniavirus (also known as Leishmania RNA virus or LRV) is a genus of double-stranded RNA virus, in the family Totiviridae. Protozoa serve as natural hosts, and Leishmaniaviruses are present in several species of the human protozoan parasite Leishmania. There are two species in this genus.^{[1] [2]}

History

The presence of virus-like particles in Leishmania hertigi was first reported in 1974.^[3] Various molecular descriptions of Leishmaniavirus were revealed over the subsequent decade, and mostly performed on members of the South American L. (Viannia) subgenus of parasites (which carries the LRV1 species) such as L. guyanensis (L.g) ^{[4] [5] [6] [7] [8] [9]} and then later in L. braziliensis (L.b).^[10] Recently, interest in these microbial viruses has been renewed by a finding that they may play a role in leishmanial pathology.^[11]

Prevalence

The prevalence of LRV1 in human parasites is still largely unknown. So far, no LRV1 has been detected in other key L. (Viannia) species, such as L. panamensis (L.p). Further, LRV1 is rarely found in species outside the Neotropics, and so far, all Paleotropic LRV isolates have shown genetic differences that were sufficient to classify them in a new subcategory named “LRV2”. This variant of LRV was first classified in a single isolate of L. major (L.m),^[12] and is recorded as the only and exceptional member of L.m to carry it. Recently, LRV2 has also been found in strains of L. aethiopica (L.ae) ^[13] isolated from biopsies of cutaneous leishmaniasis patients in the Ethiopian highlands.

Taxonomy

The following species are assigned to the genus:

• Leishmania RNA virus 1
• Leishmania RNA virus 2

Structure

Viruses in Leishmaniavirus are non-enveloped, with icosahedral geometries, and T=2 symmetry. The diameter is around 33 nm. Genomes are linear, around 5.3kb in length. The genome has 2 large open reading frames.

Genus	Structure	Symmetry !	Capsid	Genomic arrangement	Genomic segmentation
Leishmaniavirus	Icosahedral	T=2	Non-enveloped	Linear	Monopartite

Life cycle

Viral replication is cytoplasmic. Replication follows the double-stranded RNA virus replication model. Double-stranded RNA virus transcription is the method of transcription. Translation takes place by +1 ribosomal frameshifting. Protozoa serve as the natural host.

External links

• Viralzone: Leishmaniavirus
• ICTV

Notes and References

1. Web site: Viral Zone. ExPASy. 15 June 2015.
2. Web site: Virus Taxonomy: 2020 Release . International Committee on Taxonomy of Viruses (ICTV) . March 2021 . 13 May 2021.
3. Molyneux, D.H., Virus-like particles in Leishmania parasites. Nature, 1974. 249(457): p. 588.
4. Tarr, P.I., et al., LR1: a candidate RNA virus of Leishmania. Proc Natl Acad Sci U S A, 1988. 85(24): p. 9572.
5. Stuart, K.D., et al., Molecular organization of Leishmania RNA virus 1. Proc Natl Acad Sci U S A, 1992. 89(18): p. 8596.
6. Guilbride, L., et al., Distribution and sequence divergence of LRV1 viruses among different Leishmania species. Mol Biochem Parasitol, 1992. 54(1): p. 101.
7. Weeks, R.S., et al., Transcribing and replicating particles in a double-stranded RNA virus from Leishmania. Mol Biochem Parasitol, 1992. 52(2): p. 207.
8. Weeks, R., et al., LRV1 viral particles in Leishmania guyanensis contain double-stranded or single-stranded RNA. J Virol, 1992. 66(3): p. 1389.
9. Widmer, G., et al., Characterization of a RNA virus from the parasite Leishmania. Proc Natl Acad Sci U S A, 1989. 86(15): p. 5979.
10. Salinas, G., et al., Leishmania RNA viruses in Leishmania of the Viannia subgenus. Am J Trop Med Hyg, 1996. 54(4): p. 425.
11. Ives, A., et al., Leishmania RNA virus controls the severity of mucocutaneous leishmaniasis. Science, 2011. 331(6018): p. 775.
12. Scheffter, S.M., et al., The complete sequence of Leishmania RNA virus LRV2-1, a virus of an Old World parasite strain. Virology, 1995. 212(1): p. 84.
13. Zangger, H., et al., Leishmania aethiopica field isolates bearing an endosymbiontic dsRNA virus induce pro-inflammatory cytokine response. PLoS Negl Trop Dis, 2014. 8(4): p. e2836.