Virus
BK virus
Transplant nephropathy and cystitis
bee-kay VY-rus
High-yield clue
BK virus reactivation causing nephropathy in kidney transplant and hemorrhagic cystitis after stem-cell transplant is the key clue.
Overview
A non-enveloped double-stranded DNA polyomavirus that establishes latency in the urinary tract and reactivates in transplant recipients, a classic example of opportunistic reactivation in immunosuppressed hosts.
Classification
- DNA virus
- Double-stranded circular DNA
- Non-enveloped
- Family Polyomaviridae (Human polyomavirus 1)
Lab & identification clues
- Urinary 'decoy cell' cytology concept
- Blood and urine PCR viral-load vocabulary
- Renal tubular epithelial tropism concept
- Latency in uroepithelium vocabulary
Associations
- Polyomavirus-associated nephropathy in kidney transplant
- Hemorrhagic cystitis after hematopoietic transplant
- Reactivation driven by immunosuppression
- Ureteral stenosis study association
Commonly confused with
- JC virus
- Adenovirus cystitis
Frequently asked questions
What is BK virus?
A non-enveloped double-stranded DNA polyomavirus that establishes latency in the urinary tract and reactivates in transplant recipients, a classic example of opportunistic reactivation in immunosuppressed hosts.
What are the lab clues for BK virus?
Lab clues for BK virus include Urinary 'decoy cell' cytology concept, Blood and urine PCR viral-load vocabulary, Renal tubular epithelial tropism concept, and Latency in uroepithelium vocabulary.
What is BK virus commonly confused with?
BK virus is commonly confused with JC virus and Adenovirus cystitis.
Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.