Novel RNA viruses associated with avian haemosporidian parasites

Abstract

Avian haemosporidian parasites can cause malaria-like symptoms in their hosts and have been implicated in the demise of some bird species. The newly described Matryoshka RNA viruses (MaRNAV1 and MaRNAV2) infect haemosporidian parasites that in turn infect their vertebrate hosts. MaRNAV2 was the first RNA virus discovered associated with parasites of the genus Leucocytozoon. By analyzing metatranscriptomes from the NCBI SRA database with local sequence alignment tools, we detected two novel RNA viruses; we describe them as MaRNAV3 associated with Leucocytozoon and MaRNAV4 associated with Parahaemoproteus. MaRNAV3 had ~59% amino acid identity to the RNA-dependent RNA-polymerase (RdRp) of MaRNAV1 and ~63% amino acid identity to MaRNAV2. MaRNAV4 had ~44% amino acid identity to MaRNAV1 and ~47% amino acid identity to MaRNAV2. These findings lead us to hypothesize that MaRNAV_like viruses are widespread and tightly associated with the order Haemosporida since they have been described in human Plasmodium vivax, and now two genera of avian haemosporidians.

Fig 1. Phylogeny of possible RNA viruses associated with avian haemosporidian parasites.

Phylogenetic tree comparing the most closely related RdRps of MaRNAV3 and MaRNAV4 from the NCBI non-redundant protein database. The images on the right side are the expected host or environments where RNA viruses were discovered (Icons from BioRender.com). Sequences were aligned using the E-INS-I algorithm in MAFFT v7.309. Aligned sequences were put into IQ-tree v1.6.10, which chose the LG+F+I+G4 model according to BIC. The scale refers to the number of nucleotide substitutions per codon site, and the tree is unrooted although the taxon Grapevine associated narnavirus is drawn at the root. Created with BioRender.com.