In a discovery stemming from an unusual source, a domestic cat’s hunting expedition has led scientists at the University of Florida to identify a new strain of mammalian orthoreovirus. Researchers isolated the virus from an Everglades short-tailed shrew found in Gainesville. The finding, published in Microbiology Resource Announcements, provides the complete genetic blueprint for the virus, which has been named Gainesville shrew mammalian orthoreovirus type 3 strain UF-1. This discovery underscores the importance of monitoring wildlife for new pathogens that could potentially affect other animals and humans.

The scientific team began by growing the virus from the shrew’s tissue samples in a lab using cell cultures, which are layers of animal cells grown in a controlled environment. Once the virus multiplied, its genetic material was extracted and analyzed. Orthoreoviruses have a genome made of double-stranded RNA, or dsRNA, which is organized into 10 distinct segments. This is different from humans, whose genetic code is stored in DNA. Using advanced sequencing technology, the researchers pieced together the complete code for all 10 segments, creating a detailed map of the new virus’s genes and the proteins they create, such as those responsible for viral replication and structure.

To understand how this new virus fits into the larger viral family, the scientists performed a phylogenetic analysis. This process is like building a family tree for viruses by comparing their genetic sequences. They focused on the gene for the sigma-1 protein, a critical component of the virus’s outer surface that it uses to attach to and enter host cells. The analysis revealed that the shrew virus is a type 3 mammalian orthoreovirus, closely related to other strains found in different mammals. The segmented nature of orthoreovirus genomes means they can undergo a process called reassortment, where two different strains infecting the same host can swap genetic segments, potentially creating a brand-new virus, similar to how influenza viruses evolve.

While many orthoreovirus infections are mild or cause no symptoms, they have been linked to respiratory, gastrointestinal, and central nervous system diseases in various mammals, including rare cases in humans. This discovery highlights the need for continued viral surveillance in wildlife populations. The research team says the next steps include developing tests to see if humans or other local animals have been exposed to this specific strain and to study the immune response it triggers. Such work is crucial for assessing any potential risk and understanding how viruses circulate and evolve in the environment.

References

• DeRuyter, E., Williams, R. A., Subramaniam, K., & Lednicky, J. A. (2025). Coding complete sequences of the 10 genomic segments of a mammalian orthoreovirus type 3 isolated from a Blarina peninsulae shrew. Microbiology Resource Announcements, 14(7), e00219-25. https://doi.org/10.1128/mra.00219-25

• University of Florida. (2025, July 10). Scientist’s cat, again, helps discover new virus. Phys.Org; University of Florida. https://phys.org/news/2025-07-scientist-cat-virus.html