Human bocavirus (HBoV) was first detected using nonspecific gene sequencing of specimens from human subjects with respiratory illness. Viral, bacterial, and human genetic sequences were identified in 2 libraries of specimens collected at different times of year. Among the genetic sequences of many known pathogens was a parvovirus clone, which was not parvovirus B19. Bovine parvovirus and canine minute virus were the closest genetic relatives to the newly discovered parvovirus, and thus, it was called “human bocavirus” (bo for bovine and ca for canine). Although HBoV was initially described with a single genotype, 2 closely related variants have subsequently been identified and designated as “HBoV2” and “HBoV3.”