Multipartite Virus Found for First Time in Animals

    Multipartite or multicomponent viruses—which stow parts of their infectious payloads in separate particles—have been known to infect plants and fungi. Multipartite-style infections even afflict computer systems. And now, for the first time, the multipartite approach to infection has been found to affect animals. Specifically, a multipartite virus has been found in mosquitoes.

    The revelation comes from a scientific team led by researchers at U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID). The team is participating in a global effort to monitor and prepare for outbreaks of unknown viral diseases.

    “One area we are focused on is the identification and characterization of novel viruses,” said Gustavo Palacios, Ph.D., who directs USAMRIID’s Center for Genome Sciences. “This study allowed us to utilize all our tools—and even though this virus does not appear to affect mammals, we are continuing to refine those tools so we can be better prepared for the next outbreak of disease that could have an impact on human health.”

    Dr. Palacios is the senior author of a study that appeared August 25 in the journal Cell Host & Microbe, in an article entitled, “A Multicomponent Animal Virus Isolated from Mosquitoes.” The article reports that a newly discovered multipartite virus, called Guaico Culex virus (GCXV), was isolated from several species of mosquitoes in Central and South America.

    The virus does not appear to be a human pathogen, or even a mammalian one. However, deep sequencing indicated that GCXV belongs to a group of segmented viruses called Jingmenviruses, which were first discovered in 2014. In the current study, a Jingmenvirus was found in the blood of a nonhuman primate, in this case a Ugandan red colobus monkey.

    “GCXV belongs to a diverse clade of segmented viruses (Jingmenvirus) related to the prototypically unsegmented Flaviviridae,” wrote the authors of the Cell Host & Microbe article. “The GCXV genome comprises five segments, each of which appears to be separately packaged. The smallest segment is not required for replication, and its presence is variable in natural infections.”

    Experts believe that the most likely infectious viruses to make the jump to humans are those that are already circulating in other mammals, especially nonhuman primates. Phylogenetic analysis indicated that the monkey virus evaluated in the current study shared a segmented common ancestor with GCXV. However, researchers don’t yet know if all Jingmenviruses are multicomponent like the Guaico Culex virus. It is also not known whether the Jingmenvirus isolated from the monkey has a pathogenic effect.

    Taken together, the research suggests that the host range of the GCXV virus is quite diverse. Also, it provides evidence for the existence of multicomponent animal viruses and their potential relevance for animal and human health.