Genome analysis of a novel, highly divergent picornavirus from common kestrel (Falco tinnunculus): The first non-enteroviral picornavirus with type-I-like IRES

Although the number of identified avian-borne picornaviruses (family Picornaviridae) is continuously increasing there remains several species-rich avian host groups, such as the order Falconiformes (with 290 bird species) from which picornaviruses have not been identified. This study reports the first complete genome of a novel, highly divergent picornavirus, named as Falcovirus A1 (KP230449), from the carnivorous bird, the common kestrel (Falco tinnunculus, order Falconiformes). Falcovirus A1 has the longest 3DRdRp genome region and distant phylogenetic relationship to the Hepatitis A virus 1 (Hepatovirus) and Avian encephalomyelitis virus 1 (Tremovirus). It has a type-I (enterovirus-like) IRES in the 5′UTR - identified for the first time among avian-borne picornaviruses suggesting that type-I IRES is not restricted only to enteroviruses and providing further evidence of mosaicism of this region among different picornavirus genera.