Several novel viruses have recently been discovered by using microarrays or mass-sequencing methods (6, 21) . Almost all of these viruses have been found in noninvasively collected patient materials, making the correlation to clinical disease diffi cult to establish. For the picornavirus group, this issue is further complicated by knowledge that this virus family can cause a wide variety of diseases with a high proportion of nonspecifi c symptoms or asymptomatic infections (5) .