High prevalence of infection with three new human polyomaviruses
Polyomaviruses occupy a replicative niche in animals from birds to humans. Two human polyomaviruses, BKV and JCV, were discovered in 1971 and within the last two years, three new polyomaviruses have been found in humans: KI (KIV), WU (WUV), and Merkel Cell (MCV) polyomavirus. MCV was identified in Merkel Cell carcinomas, a rare skin cancer. KIV and WUV were detected in nasal secretions, and may be respiratory viruses. Previously, it had not been determined what percentage of the human population is exposed to KIV, WUV, and MCV, and when initial exposure to these viruses occurs. A new study now suggests that a majority of the human population has been exposed to newly discovered KIV, WUV, and Merkel cell (MCV) human polyomaviruses. The results, based on antibody measurements in serum samples, also suggest that infection with these viruses occurs early in childhood.
In this study, researchers tested over 2220 anonymous donor blood samples (more than 1500 adults and more than 700 young people). They measured antibodies that reacted with specific viral proteins. In addition to KIV, WUV, MCV, BKV, and JCV, two monkey polyomaviruses, SV40 and lymphotropic polyomavirus (LPV), were also studied. Antibodies to LPV were detected in a fraction of people (15%), confirming previous studies suggesting that a relative of this virus may infect humans. The majority of antibodies against SV40 proteins may be attributed to the immune response to BKV. The diseases caused by these viruses remain to be fully described. Future studies will be important to help determine differences in the prevalence of these infections in other geographic areas.
Seroepidemiology of Human Polyomaviruses. 2009 PLoS Pathog 5(3): e1000363
In addition to the previously characterized viruses BK and JC, three new human polyomaviruses (Pys) have been recently identified: KIV, WUV, and Merkel Cell Py (MCV). Using an ELISA employing recombinant VP1 capsid proteins, we have determined the seroprevalence of KIV, WUV, and MCV, along with BKV and JCV, and the monkey viruses SV40 and LPV. Soluble VP1 proteins were used to assess crossreactivity between viruses. We found the seroprevalence (+/- 1%) in healthy adult blood donors (1501) was SV40 (9%), BKV (82%), JCV (39%), LPV (15%), KIV (55%), WUV (69%), MCV strain 350 (25%), and MCV strain 339 (42%). Competition assays detected no sero-crossreactivity between the VP1 proteins of LPV or MCV or between WUV and KIV. There was considerable sero-crossreactivity between SV40 and BKV, and to a lesser extent, between SV40 and JCV VP1 proteins. After correcting for crossreactivity, the SV40 seroprevalence was ~2%. The seroprevalence in children under 21 years of age (n=721) for all Pys was similar to that of the adult population, suggesting that primary exposure to these viruses likely occurs in childhood.
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Tags: Blood, Health, Medicine, Microbiology, Polyomavirus, Science, Virology
