Guaico Culex Virus: Researchers Find Multicomponent Animal Virus
For the first time, researchers have identified a multicomponent RNA virus – one containing different segments of genetic material in separate particles, rather than a single strand of genetic material – that can infect animals.
Multicomponent viruses, which separately package different genome segments, were thought to be restricted to plant and fungal hosts. Ladner et al characterize the multicomponent animal virus GCXV and describe an evolutionarily related, segmented virus in a nonhuman primate. This image depicts the presence of different viral RNA segments of GCXV within infected cells. Image credit: Michael Lindquist.
This new pathogen was isolated from mosquitoes of the genus Culex captured in Panama, Peru, and Trinidad.
The virus does not appear to be a human pathogen, or even a mammalian one, according to Dr. Jason Ladner, a staff scientist from the U.S. Army Medical Research Institute of Infectious Diseases and first author of a paper in the journal Cell Host & Microbe .
“This virus has tentatively been designated Guaico Culex virus (GCXV), on the basis of the first collection location (near the Guaico community in Trinidad) and the genus of the mosquito that appears to serve as its primary host,” the authors said.
“Although multicomponent genomes are relatively common among RNA viruses that infect plants and fungi, this method of genome organization has not previously been seen in animal viruses.”
“Our finding that these viruses are present in mosquitoes is going to challenge us to re-evaluate some of our assumptions about them,” Dr. Ladner said.
Multicomponent viruses use a method of transmission that’s different from other viruses known to infect animals.
Instead of being contained in a single viral particle, their genomes are segmented and encapsulated among multiple particles.
A yellow fever virus, for example, has all its genetic material packaged into a single particle. Therefore, one particle is enough to infect a cell.
But in order for a multicomponent virus to establish an infection, the cell has to get infected with at least one particle of each type.
“The GCXV genome comprises five segments, each of which appears to be separately packaged,” the scientists said.
“The smallest segment is not required for replication, and its presence is variable in natural infections.”
Further analysis demonstrates that GCXV belongs to the Jingmenvirus group, a recently discovered and highly diverse clade of segmented viruses related to the prototypically unsegmented Flaviviridae (a large family of viruses that includes human pathogens such as yellow fever, West Nile and Japanese encephalitis viruses).