Current Perspectives on JC Polyomavirus Transmission and Associated Diseases: Implications for Prevention in Risk Populations

JC polyomavirus (JCPyV) is a worldwide-distributed human virus. Primary infection with JCPyV is usually asymptomatic and followed by a lifelong persistent infection. In situations of profound immunosuppression or prolonged treatment with specific immunomodulatory drugs, such as natalizumab, viral reactivation can occur and lead to the development of JCPyV-associated diseases. Progressive multifocal leukoencephalopathy (PML), a severe demyelinating disease of the central nervous system, is the most common clinical manifestation of JCPyV reactivation. Less frequently, viral reactivation may be associated with granule cell neuronopathy, encephalopathy, and meningitis. However, the pathogenesis of these diseases remains a subject of debate. To date, no treatment is available for JCPyV infection. Nevertheless, some therapeutic options have been explored. Despite its ubiquity, the main mode of JCPyV transmission remains unclear. Epidemiological data suggests that primary infection may be acquired in childhood and throughout life, with the involvement of different routes of transmission. In the absence of an effective treatment, the prevention of infection is crucial in risk groups, such as immunosuppressed or natalizumab-treated patients. Therefore, until the achievement of an effective antiviral molecule or a prophylactic vaccine, prevention measures will rely on avoiding transmission, for which it is crucial to understand how transmission occurs. The present review emphasizes the current data on JCPyV transmission routes and associated diseases, including pathogenesis, diagnosis and potential treatment options, highlighting the importance of further studies.