Kobuviruses are members of the large and growing family Picornaviridae. Until now, two official, Aichi virus and Bovine kobuvirus, and one candidate kobuvirus species, 'porcine kobuvirus', have been identified in human, cattle and swine, respectively. In addition, kobu-like viruses were detected very recently in the bat. Aichi virus could be one of the causative agents of gastroenteritis in humans, and kobuviruses probably also cause diarrhoea in cattle and swine. Although Aichi virus has been detected relatively infrequently (0-3%) in human diarrhoea, high seroprevalence, up to 80-95% at the age of 30-40, was found indicating the general nature of infection in different human populations. In the previous years, much new information has accumulated relating to kobuviruses and their host species. This review summarises the current knowledge on kobuviruses including taxonomy, biology and viral characteristics, and covers all aspects of infection including epidemiology, clinical picture, host species diversity, laboratory diagnosis and it gives a summary about possible future perspectives.

A large, highly prolific swine farm in Hungary had a 2-year history of neurologic disease among newly weaned (25- to 35-day-old) pigs, with clinical signs of posterior paraplegia and a high mortality rate. Affected pigs that were necropsied had encephalomyelitis and neural necrosis. Porcine astrovirus type 3 was identified by reverse transcription PCR and in situ hybridization in brain and spinal cord samples in 6 animals from this farm. Among tissues tested by quantitative RT-PCR, the highest viral loads were detected in brain stem and spinal cord. Similar porcine astrovirus type 3 was also detected in archived brain and spinal cord samples from another 2 geographically distant farms. Viral RNA was predominantly restricted to neurons, particularly in the brain stem, cerebellum (Purkinje cells), and cervical spinal cord. Astrovirus was generally undetectable in feces but present in respiratory samples, indicating a possible respiratory infection. Astrovirus could cause common, neuroinvasive epidemic disease.

Birds are frequent sources of emerging human infectious diseases. Viral particles were enriched from the feces of 51 wild urban pigeons (Columba livia) from Hong Kong and Hungary, their nucleic acids randomly amplified and then sequenced. We identified sequences from known and novel species from the viral families Circoviridae, Parvoviridae, Picornaviridae, Reoviridae, Adenovirus, Astroviridae, and Caliciviridae (listed in decreasing number of reads), as well as plant and insect viruses likely originating from consumed food. The near full genome of a new species of a proposed parvovirus genus provisionally called Aviparvovirus contained an unusually long middle ORF showing weak similarity to an ORF of unknown function from a fowl adenovirus. Picornaviruses found in both Asia and Europe that are distantly related to the turkey megrivirus and contained a highly divergent 2A1 region were named mesiviruses. All eleven segments of a novel rotavirus subgroup related to a chicken rotavirus in group G were sequenced and phylogenetically analyzed. This study provides an initial assessment of the enteric virome in the droppings of pigeons, a feral urban species with frequent human contact.

The family Astroviridae consists of two genera, Avastrovirus and Mamastrovirus, whose members are associated with gastroenteritis in avian and mammalian hosts, respectively. We serendipitously identified a novel porcine astrovirus in a fecal specimen from a domestic pig (Sus scrofa domestica) in Hungary. Sequencing of a fragment indicated that it was an ORF1b/ORF2/3'UTR sequence, and it has been submitted to the database as porcine astrovirus type 2 (PAstV-2/Hungary/2007) with accession number GU562296. Its unique sequence characteristics and its phylogenetic position suggest that PAstV-2 could be an important link between previously reported astroviruses and that a genetically divergent lineage of astroviruses exist in piglets.

Members of the genus Enterovirus (family Picornaviridae) are believed to be common and widespread among humans and different animal species, although only a few enteroviruses have been identified from animal sources. Intraspecies recombination among human enteroviruses is a well-known phenomenon, but only a few interspecies examples have been reported and, to our current knowledge, none of these have involved non-primate enteroviruses. In this study, we report the detection and complete genome characterization (using RT-PCR and long-range PCR) of a natural interspecies recombinant bovine/porcine enterovirus (ovine enterovirus type 1; OEV-1) in seven (44 %) of 16 faecal samples from 3-week-old domestic sheep (Ovis aries) collected in two consecutive years. Phylogenetic analysis of the complete coding region revealed that OEV-1 (ovine/TB4-OEV/2009/HUN; GenBank accession no. JQ277724) was a novel member of the species Porcine enterovirus B (PEV-B), implying the endemic presence of PEV-B viruses among sheep. However, the 59 UTR of OEV-1 showed a high degree of sequence and structural identity to bovine enteroviruses. The presumed recombination breakpoint was mapped to the end of the 59 UTR at nucleotide position 814 using sequence and SimPlot analyses. The interspeciesrecombinant nature of OEV-1 suggests a closer relationship among bovine and porcine enteroviruses, enabling the exchange of at least some modular genetic elements that may evolve independently.

Members of the family Picornaviridae are important pathogens of humans and animals, although compared with the thousands of known bird species (.10 000), only a few (n511) picornaviruses have been identified from avian sources. This study reports the metagenomic detection and complete genome characterization of a novel turkey picornavirus from faecal samples collected from eight turkey farms in Hungary. Using RT-PCR, both healthy (two of three) and affected (seven of eight) commercial turkeys with enteric and/or stunting syndrome were shown to be shedding viruses in seven (88 %) of the eight farms. The viral genome sequence (turkey/M176/2011/HUN; GenBank accession no. JQ691613) shows a high degree of amino acid sequence identity (96 %) to the partial P3 genome region of a picornavirus reported recently in turkey and chickens from the USA and probably belongs to the same species. In the P1 and P2 regions, turkey/M176/2011/HUN is related most closely to, but distinct from, the kobuviruses and turdivirus 1. Complete genome analysis revealed the presence of characteristic picornaviral amino acid motifs, a potential type II-like 59 UTR internal ribosome entry site (first identified among avianorigin picornaviruses) and a conserved, 48 nt long 'barbell-like' structure found at the 39 UTR of turkey/M176/2011/HUN and members of the picornavirus genera Avihepatovirus and Kobuvirus. The general presence of turkey picornavirus-a novel picornavirus species-in faecal samples from healthy and affected turkeys in Hungary and in the USA suggests the worldwide occurrence and endemic circulation of this virus in turkey farms. Further studies are needed to investigate the aetiological role and pathogenic potential of this picornavirus in food animals. divided into three regions: P1, P2 and P3. The P1 region encodes the viral capsid proteins (VP4-VP2-VP3-VP1), whilst the P2 and P3 regions encode proteins involved in protein processing (2A pro , 3C pro and 3CD pro) and genome replication (2B, 2C, 3AB, 3B VPg , 3CD pro , 3D pol) (Racaniello, 2007). In addition, aphthoviruses, cardioviruses, erboviruses, kobuviruses, sapeloviruses, senecaviruses, teschoviruses and 'turdiviruses' (proposed) encode a leader (L) protein before the P1 region. Members of the family Picornaviridae are important pathogens associated with several diseases. Picornavirus infections sometimes cause severe disorders of the gastrointestinal tract and the respiratory, neural, hepatocellular and circulatory systems in humans and animals (Racaniello, 2007; Alexandersen et al., 2012). In addition, approximately threequarters of all emerging infectious disease agents (including 3These authors contributed equally to this work. The GenBank/EMBL/DDBJ accession numbers for the complete genome sequence of novel turkey picornavirus are JQ691613-JQ691615.

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Recently, a novel group of unclassified single-stranded (ss) circular small DNA viruses (called stool-associated circular virus; SCV) were identified in fecal samples of three mammalian species, namely, chimpanzee (ChiSCV), pig (PoSCV) and cattle (BoSCV). In this study, a novel genomic relative of stool-associated circular virus (TuSCV, KF880727) was detected in faeces of an avian species, namely, domestic turkey (Meleagris gallopavo). The complete TuSCV genome is 2479 nt long and has two open reading frames (ORF), which are bidirectionally transcribed and separated by intergenic regions. The ORF1 (replicase) and ORF2 (capsid) proteins have 77 % and 48 % aa sequence identity to different porcine-origin SCVs.