JC and BK Polyomaviruses (JCV & BKV)

Causative Agents

BK and JC viruses (BKV and JCV) are polyomaviruses belonging to polyomaviridae family. BKV and JCV are composed of an icosahadral viral particle (virion) containing 5000 base pair double-stranded circular DNA molecule and surrounded by a protein capsid. These viruses do not possess a lipid envelope. BKV and JCV infections are asymptomatic as they remain latent in about 90% of the main human population and may lead to infections resulting in severe diseases such as hematuria, hemorrhagic cystisis, ureteric stenosis, etc once they become reactivated upon suppression of the immune system. There are 7 distinct genotypes of JC and 4 of BK classified. [1],[2],[3]

Epidemiology

Most of the primary polyomavirus infections occur during childhood. Serological studies suggest that more than 70% of adults possess antibodies against BK or JC virus. There are serological evidences suggesting the reactivation of the JCV and BKV viruses during the pregnancy period of 5-10 % of the women. [4],[5]

Modes of Transmission

Although little is known about the route-of-transmission among humans, high infection rate suggests airborne transmission. Abundance of JCV and BKV in sewages also suggests transmission via contaminated food and water. Semen, blood products and organ transplantation, particularly renal allografts are other potential routes. [6]

Diagnosis

The diagnosis and monitoring of the BK and JCV infections are managed through histological and cytological tests with the help of high electron and fluorescence microscopy. Also the serological methods (haemagglutination inhibition test, ELISA, RIAs) based on the detection of antibodies against Polyoma viruses are used widespread. Early diagnosis of BK and JCV reactivation is paramount for prevention of the possible severe diseases that even positively impacts organ survival. [7],[8]

Detecting BKV and JCV DNA in a multitude of specimen types using polymerase chain reaction (PCR) is the most reliable and quick method with highest sensitivity and specificity.

References

1) Baron, Samuel. (1996). Medical Microbiology, 4th ed., The University of Texas Medical Branch at Galveston . ISBN 0-9631172-1-1 .

2) Rajpoot DK, Gomez A, Tsang W, Shanberg A: Ureteric and urethral stenosis: a complication of BK virus infection in a pediatric renal transplant patient. Pediatr Transplant 2007, 11(4):433-5

3) Fioriti D, Degener AM, Mischitelli M, Videtta M, Arancio A, Sica S, Sora F, Pietropaolo V: BKV infection and hemorrhagic cystitis after allogeneic bone marrow transplant. Int J Immunopathol Pharmacol 2005, 18(2):309-16

4) Padgett BL, Walker DL: Prevalence of antibodies in human sera against JC virus, an isolate from a case of progressive multifocal leukoencephalopathy. J Infect Dis 1973, 127:467-470

5) Lukasik J, Scott TM, Andryshak D, Farrah SR: Influence of salts on virus adsorption to microporous filters. Appl Environ Microbiol 2000, 66:2914–2920

6) McQuaig SM, Scott TM, Harwood VJ, Farrah SR, Lukasik JO: Detection of human derived fecal pollution in environmental waters using a PCR-based human polyomavirus assay. Appl Environ Microbiol 2006, 72:7567–7574

7) Hogan TF, Padgett BL, Walker DL, Borden EC, McBain JA: Rapid detection and identification of JC virus and BK virus in human urine by using immunofluorescence microscopy. J Clin Microbiol 1980, 11(2):178-83.

8)Hamilton RS, Gravell M, Major EO: Comparison of antibody titers determined by hemagglutination inhibition and enzyme immunoassay for JC virus and BK virus. J Clin Microbiol 2000, 38(1):105-9

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