[1] Although WU virus has been detected in a variety of locations around the world, indicating a global distribution, estimates of its prevalence vary.

[4] Another 2009 study found around 80% seroprevalence for adults, with age patterns indicating that infants may inherit maternal antibodies against both WU and KI.

[5] A 2016 study of polyomavirus seroprevalence found WU virus in 97.4% of samples from another American population.

[9] While no clear association with clinical symptoms has been identified, there is weak indication that WU and KI viruses may have pathogenic potential in immunocompromised patients.

[11] In an updated classification system for the polyomavirus family proposed in 2016, WU virus is classified as a member of the genus Betapolyomavirus along with BK, JC, and KI.