One facet of fast evolving RNA viruses that induce acute infections (as the case of HPeV) is that they are likely candidates for jumps between species boundaries [29] . While the latter appears to be clearly established for e.g. SARS-CoV or influenza H5N1, a zoonotic link remains to be elucidated for HPeV. Because Ljungan virus shares a close phylogenetic proximity with HPeV virus, it is likely that both species have had a common ancestor [52] . Moreover, the reservoir host for Ljungan virus is Myodes glareolus, a widely distributed rodent commonly named as bank vole [4] . Despite the connection of Ljungan virus infection and human disease still remains to be clarified, bank voles are recognized as the reservoirs of other infectious agents, e.g. Puumala Hantavirus [53] and have been linked to a significant number of outbreaks over Europe [54] [55] [56] .