New insights into the genetic diversity of Leishmania RNA Virus 1 and its species-specific relationship with Leishmania parasites.

Cutaneous leishmaniasis is a neglected parasitic disease that manifests in infected individuals under different phenotypes, with a range of factors contributing to its broad clinical spectrum. One factor, Leishmania RNA Virus 1 (LRV1), has been described as an endosymbiont present in different species of Leishmania. LRV1 significantly worsens the lesion, exacerbating the immune response in both experimentally infected animals and infected individuals. Little is known about the composition and genetic diversity of these viruses. Here, we investigated the relationship between the genetic composition of LRV1 detected in strains of Leishmania (Viannia) braziliensis and L. (V.) guyanensis and the interaction between the endosymbiont and the parasitic species, analyzing an approximately 850 base pair region of the viral genome. We also included one LRV1 sequence detected in L. (V.) shawi, representing the first report of LRV1 in a species other than L. braziliensis and L. guyanensis. The results illustrate the genetic diversity of the LRV1 strains analyzed here, with smaller divergences detected among viral sequences from the same parasite species. Phylogenetic analyses showed that the LRV1 sequences are grouped according to the parasite species and possibly according to the population of the parasite in which the virus was detected, corroborating the hypothesis of joint evolution of the viruses with the speciation of Leishmania parasites.