The first RNA viruses detected in a trypanosome

Area of Science:

• Microbiology
• Virology
• Parasitology

Background:

• Trypanosomatids are flagellated parasites responsible for significant human diseases.
• RNA viruses infecting trypanosomatids are increasingly recognized for their impact on disease severity.
• No RNA viruses had been previously identified in the Trypanosoma genus.

Purpose of the Study:

• To report the first discovery and molecular characterization of RNA viruses in the Trypanosoma genus.
• To investigate the diversity and evolutionary relationships of these newly identified viruses.
• To explore the potential influence of vector ecology on viral acquisition in trypanosomes.

Main Methods:

• Discovery and identification of RNA viruses in Trypanosoma platydactyli.
• Molecular characterization of viral genomes, including leishmaniavirus and narnaviruses.
• Phylogenetic analysis to infer evolutionary relationships and origins of the viruses.

Main Results:

• The first RNA viruses, a leishmaniavirus and two narnaviruses, were identified in Trypanosoma platydactyli.
• The leishmaniavirus genome exhibited conserved features typical of its genus.
• Phylogenetic analysis placed the leishmaniavirus close to those found in Old World Leishmania spp., suggesting shared vector ecology.
• The narnaviruses showed distinct origins but clustered with other trypanosomatid-infecting viruses, indicating historical exchanges.

Conclusions:

• This study significantly expands the known diversity of RNA viruses within trypanosomatids and the genera they infect.
• Vector ecology, particularly feeding behavior, may play a crucial role in viral acquisition by trypanosomes.
• Overlooked trypanosomatid species transmitted by Nematocera are promising targets for future viral discoveries.