Bovine Kobuvirus in Europe

To the Editor: Picornaviruses (family Picornaviridae) are small, nonenveloped viruses with single-stranded, positive-sense genomic RNA. Picornaviruses are currently divided into 8 genera: Enterovirus, Aphthovirus, Cardiovirus, Hepatovirus, Parechovirus, Erbovirus, Teschovirus, and Kobuvirus (1). To date, the genus Kobuvirus consists of 2 officially recognized species, Aichi virus and Bovine kobuvirus, and 1 porcine kobuvirus as a candidate species (2–4). Aichi virus (strain A846/88) was first isolated in 1991 from feces of a person with acute gastroenteritis (2). Bovine kobuvirus (strain U-1) was detected in 2003 in bovine serum and fecal samples from clinically healthy cattle (3); in 2008, it was isolated from cattle with diarrhea (5). Aichi virus and bovine kobuvirus were first isolated in Japan. Porcine kobuvirus (strain S-1-HUN) was recently identified from domestic pigs in Hungary (4). Aichi viruses have been also detected in other countries in Asia (6), Europe (7,8), South America (7), and northern Africa (9). Bovine kobuvirus, however, has not been detected outside Asia (Japan and Thailand) (3,5).

1-7.6 years (n = 17). In February 2008, 26 more samples were collected from animals <20 days of age on this farm. On the sampling days, no diarrhea was reported.
Of the 32 samples collected in 2002, two (6.25%), from 1-year-old animals, were positive for bovine kobuvirus; however, no kobuvirus was found in the samples from 2008. The 2 partial 3D regions (216 nt) were genetically identical. Strain kobuvirus/bovine/Aba-Z20/2002/Hungary (FJ225406) had 89%-94% nucleotide and 96%-100% amino acid identities to the 19 known Asian bovine kobuvirus strains in GenBank. Strain Z20 had 93% and 95% nucleotide identities to U-1 in 3D/3′-UTR (862 nt) and 3′-UTR (174 nt) regions, respectively. Phylogenetic analysis of the overlapping partial 3D nucleotide sequences of bovine kobuvirus strain Z20 from Hungary, together with all published bovine kobuvirus strains available in the GenBank database, are shown in the Figure. Aichi virus and porcine kobuvirus were included in the tree as outlier viruses. The phylogenetic tree confi rmed that strain Z20 belonged to bovine kobuviruses (Figure).
Our detection of bovine kobuviruses in Europe confi rms a wider geographic presence of this type of picornavirus in cattle and suggests that bovine kobuvirus is common and potentially distributed worldwide. Genetic diversity was seen, based on the 3D regions of bovine kobuviruses; however, this region shows the highest genetic identity among the kobuvirus genetic regions (3,4). Strain Z20 also confi rms the 174-nt 3′-UTR region of bovine kobuvirus. At this time it is not clear what diseases (including gastroenteritis) are associated with bovine kobuvirus (3,5). In addition to the bovine kobuvirus, 2 other RNA viruses that are transmitted by the fecal-oral route (genotypes GIII/1 and GIII/2 of bovine noroviruses and rotavirus) were detected at the same time from these apparently healthy animals. More epidemiologic and molecular studies are required to determine the relevance, distribution, and diversity of bovine kobuvirus in cattle.

Candidate Porcine Kobuvirus, China
To the Editor: The picornaviruses constitute a large, diverse family of positive-sense RNA viruses, which comprise 8 genera: Enterovirus, Aphthovirus, Cardiovirus, Hepatovirus, Parechovirus, Erbovirus, Kobuvirus, and Teschovirus (1). The genus Kobuvirus contains 2 known species: Aichi virus, which was identifi ed in humans in 1989 and was found to be associated with human acute gastroenteritis (2), and Bovine kobuvirus, which was identifi ed in 2003 in apparently healthy cattle (3). In our study, we identifi ed a candidate novel strain of kobuvirus from porcine fecal specimens; this strain is markedly different from Aichi virus and bovine kobuvirus.
Using reverse transcription-PCR (RT-PCR) to characterize calicivirus in porcine fecal specimens with a primer pair of p289/VN3T20 designed for a 3-kb fragment of the virus, we observed an unexpected band on aga-