The BK virus is a member of the polyomavirus family. Past infection with the BK virus is widespread, but significant consequences of infection are uncommon.

Clinically, BK virus becomes relevant in immunocompromised patients. It is notable as a cause for hemorrhagic cystitis in bone marrow transplant recipients. In renal transplant patients, it is associated with ureteral stenosis and interstitial nephritis.

Viruses | Polyomaviruses