Since their discovery in 1971, the polyomaviruses JC (JCPyV) and BK (BKPyV), isolated from patients with progressive multifocal leukoencephalopathy and polyomavirus-associated nephropathy, respectively, remained for decades as the only known members of the Polyomaviridae family of viruses of human origin. Over the past five years, the application of new genomic amplification technologies has facilitated the discovery of several novel human polyomaviruses (HPyVs), bringing the present number to 10. These HPyVs share many fundamental features in common such as genome size and organization. Infection by all HPyVs is widespread in the human population, but they show important differences in their tissue tropism and association with disease. Much remains unknown about these new viruses.
This review discusses the problems associated with studying HPyVs, such as the lack of culture systems for the new viruses and the gaps in our basic understanding of their biology, and summarizes what is known so far about their distribution, life cycle, tissue tropism, their associated pathologies (if any), and future research directions.
The Rapidly Expanding Family of Human Polyomaviruses: Recent Developments in Understanding Their Life Cycle and Role in Human Pathology. (2013) PLoS Pathog 9(3): e1003206. doi:10.1371/journal.ppat.1003206
Until a few years ago the polyomavirus family (Polyomaviridae) included a dozen viruses identified in avian and mammal hosts. Two of these, the JC and BK-polyomaviruses isolated long time ago, are known to infect humans and cause severe illness in immunocompromized hosts. Since 2007 an unprecedented number of eight new polyomaviruses was discovered in humans. Among them are the KI and WU-polyomaviruses identified in respiratory samples, the Merkel cell polyomavirus found in skin carcinomas, and the polyomavirus associated with trichodysplasia spinulosa, a skin disease of transplant patients. Another four new human polyomaviruses were identified, HPyV6, HPyV7, HPyV9, and the Malawi polyomavirus, so far not associated with any disease. In the same period several new mammal polyomaviruses were described.
This review summarizes the recent developments in studying the new human polyomaviruses, and touches upon several aspects of polyomavirus virology, pathogenicity, epidemiology and phylogeny.
From Stockholm to Malawi: recent developments in studying human polyomaviruses. J Gen Virol. 19 Dec 2012