Study reveals diverse virulence patterns in no-known-vector flaviviruses using mouse models
Researchers tested 12 flaviviruses thought to spread without arthropod vectors in immunocompromised mice and found that 7 of them caused severe disease and death, while causing no symptoms in normal mice. No-known-vector flaviviruses (NKVFVs) are isolated from rodents and bats but not arthropods, making their transmission routes and pathogenic mechanisms poorly understood. Understanding these viruses' behavior is important for assessing potential public health risks and developing targeted interventions.
A preprint study examined the pathogenic properties of 12 no-known-vector flaviviruses (NKVFVs) by infecting three types of mice: wild-type, interferon-signaling-deficient (Ifnar1-/-), and doubly-deficient (Ifnar1-/- Ifngr1-/-) animals. Seven NKVFVs—including Entebbe bat virus, Sokuluk virus, Yokose virus, Modoc virus, Apoi virus, Dakar bat virus, and Rio Bravo virus—proved lethal in the singly-deficient mice within 9 days, accompanied by detectable viremia. All tested viruses were lethal in doubly-deficient mice and produced higher viral loads than in singly-deficient mice. Notably, wild-type mice showed no disease signs or viremia from any virus tested. The researchers also evaluated replication of three selected viruses in mouse fibroblasts, macrophages, and bat cell lines. The findings demonstrate substantial variation in virulence among NKVFVs and suggest that interferon signaling plays a critical protective role against these pathogens.
What's missing
The study's own limitations are not detailed in the provided abstract, including sample sizes, statistical methods, potential cross-contamination controls, and whether results in mouse models reliably predict behavior in natural bat or rodent hosts. Additionally, the mechanisms by which these viruses are naturally transmitted (if not by arthropods) remain unexplored in this work.
What different sources said
- bioRxivCenter
No-known-vector flaviviruses exhibit diverse replication and virulence phenotypes in mice
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