New Jersey polyomavirus (NJPyV), also known as human polyomavirus 13, is a circular double‑stranded DNA virus discovered in 2014 from the vascular endothelial cells of a pancreatic transplant recipient in New Jersey. It belongs to the family Polyomaviridae and is the thirteenth human polyomavirus identified.
Explanation
NJPyV has a typical polyomavirus genome of about 5.1 kilobase pairs encoding six proteins: the small tumor antigen, large tumor antigen, an alternative tumor antigen (ALTO), and the structural proteins VP1, VP2 and VP3. These genes are organized in early and late regions analogous to other polyomaviruses, and the presence of the ALTO protein reflects an alternative splicing product also observed in trichodysplasia spinulosa polyomavirus. Phylogenetically NJPyV is classified in the genus Alphapolyomavirus and shows the highest sequence similarity to polyomaviruses infecting chimpanzees and bats. The VP1 protein shares roughly 48–56 % amino acid identity with BK, JC and Merkel cell polyomaviruses. NJPyV was isolated from an immunosuppressed transplant patient with blindness, vasculitis, myopathy and dermatosis. Its genome has not been detected in other clinical cases, and no causal link between NJPyV and disease has been established. Prevalence studies are scarce; serosurveys in Italy and the Netherlands reported anti‑NJPyV antibodies in 31–58 % and around 5 % of adults respectively. A large Japanese study detected antibodies in only 1.8 % of individuals aged 1–70 years, suggesting low circulation. These variations may reflect cross‑reactive antibodies or regional differences, and the overall seroprevalence and transmission route remain uncertain. It is possible that the index case represented reactivation of a latent infection under immunosuppression.
Case Report and Population Studies
The original NJPyV genome was identified using high‑throughput sequencing of vascular endothelium from a pancreatic transplant recipient who developed blindness, vasculitis, muscular weakness and a skin eruption. Researchers excluded known pathogens before describing this novel virus. Subsequent investigations have screened healthy individuals for antibodies against NJPyV. A cohort study in Italy recorded seropositivity in about one third to half of adults, whereas studies in the Netherlands and Japan reported much lower rates around 5 % and 1.8 %. NJPyV DNA has rarely been detected in clinical or environmental samples. To date no additional cases of disease have been attributed to this virus. The combined evidence suggests NJPyV may be a human-tropic alphapolyomavirus with limited circulation or cross‑reactive immunity; its natural host, transmission mode and pathogenic potential require further study. NJPyV represents the thirteenth human polyomavirus and exemplifies how modern sequencing uncovers rare viruses. Despite encoding the same functional proteins as other polyomaviruses, it has been found only in one immunocompromised individual, and population studies show low and variable seroprevalence. Continued surveillance is needed to determine whether NJPyV is a rare human virus or a cross‑species transfer. Related Terms: Alphapolyomavirus, Human Polyomavirus 9 (HPyV9), Lyon IARC polyomavirus (LIPyV), MW polyomavirus (MWPyV/HPyV10), STL polyomavirus (STLPyV)