Narrative Review of Variegated Squirrel Bornavirus 1 (VSBV-1) in Captive Exotic Squirrels

Variegated squirrel bornavirus 1 (VSBV-1) is a recently identified zoonotic virus associated with fatal encephalitis in humans. A literature search in electronic databases such as PubMed, Web of Science, Scopus, and Google Scholar was performed using the following search terms: “VSBV-1”, “orthobornavirus”, “squirrel”, “zoonotic encephalitis”, and “mammalian bornavirus”, to identify peer-reviewed literature relevant to the veterinary and zoonotic aspects of VSBV-1. This narrative review summarizes the current knowledge on VSBV-1 with emphasis on veterinary aspects, including taxonomy, epidemiology, clinical presentation, diagnostics, hypothetical transmission routes, surveillance strategies, and proposed biosecurity measures. However, evidence regarding virus shedding, natural reservoirs, distribution, and transmission pathways is presently absent. VSBV-1 may persist undetected in infected squirrels due to the absence of clinical signs and limited surveillance efforts. Large-scale epidemiological studies have not yet been performed. Given the limited understanding of viral epidemiology and the severe course of zoonotic infection, a precautionary approach is warranted. Structured surveillance, control of animal movements, and occupational protection are essential to limit both viral spread and the risk of zoonotic infection. Future research should focus on identifying natural reservoirs, virus distribution in captive squirrel populations, transmission pathways, and improving diagnostic tools.