Frequent detection of the parvoviruses, PARV4 and PARV5, in plasma from blood donors and symptomatic individuals

Background: Plasma pools used in the manufacture of blood- and plasma-derived medicinal products are frequently contaminated with parvovirus B19. The presence of the novel human parvovirus PARV4 and a related variant PARV5 in manufacturing plasma pools was recently demonstrated. Another recently identified parvovirus, human bocavirus (HBoV), has been identified in respiratory samples from children with lower respiratory tract disease. Study Design and Methods: Recent and archived manufacturing plasma pools, as well as plasma from healthy blood donors (individual donations; pools of 16 donations) and febrile patients, were examined for the presence of PARV4 and PARV5 with conventional and TaqMan polymerase chain reaction assays. In addition, highly sensitive assays were used to examine the presence of HBoV DNA in manufacturing pools. Results: Of 351 recent manufacturing plasma pool samples, 14 (4%) tested positive for the presence of PARV4 and PARV5. This frequency was elevated in the archived pools. Viral loads ranged from less than 100 up to 4 million copies per mL plasma, with some pools containing a mixture of both viruses. In individual plasma samples from healthy blood donors and febrile patients, the frequencies of detection were 2 and 6 percent, respectively. No HBoV sequences were identified in manufacturing plasma pools (n = 167). Conclusion: PARV4 and PARV5 are readily detected in manufacturing plasma pools, test pools (constructed from 16 donations), and individual donations derived from healthy blood donors. The prevalence of these viruses was increased in plasma samples from febrile patients. Despite the use of highly sensitive assays for HBoV, it was not possible to identify manufacturing plasma pools containing HBoV sequences.