Complete Nucleotide Sequence and Genetic Organization of Aichi Virus, a Distinct Member of the Picornaviridae Associated with Acute Gastroenteritis in Humans

Abstract

The complete nucleotide sequence of a novel enteric virus, Aichi virus, associated with nonbacterial acute gastroenteritis in humans was determined. The Aichi virus genome proved to be a single-stranded positive-sense RNA molecule with 8,251 bases excluding a poly(A) tail; it contains a large open reading frame with 7,302 nucleotides that encodes a potential polyprotein precursor of 2,433 amino acids. The genome contains a 5′ nontranslated region (NTR) with 712 bases and a 3′ NTR with 240 bases followed by a poly(A) tail. The structure of the genome, VPg–5′ NTR–leader protein–structural proteins–nonstructural proteins–3′ NTR–poly(A), was found to be typical of a picornavirus. The VP0-VP3 and VP3-VP1 cleavage sites were determined to be Q-H and Q-T, respectively, by N-terminal amino acid sequence analyses using purified virion proteins. Possible cleavage sites, Q-G, Q-A, and Q-S, which cleave P2 and P3 polyproteins were found to be similar to those of picornaviruses. A dendrogram based on 3Dpol proteins indicated that Aichi virus is genetically distinct from the known six genera of picornaviruses including entero-, rhino-, cardio-, aphtho-, and hepatovirus and echovirus 22. Considering this together with other properties of the virus (T. Yamashita, S. Kobayashi, K. Sakae, S. Nakata, S. Chiba, Y. Ishihara, and S. Isomura, J. Infect. Dis. 164:954–957, 1991), we propose that Aichi virus be regarded as a new genus of the family Picornaviridae.

Phylogeny and prevalence of kobuviruses in dogs and cats in the UK

“…Yamashita et al (1998) showed that the VP0 capsid protein is expressed in the mature particle in Aichi virus and does not undergo cleavage (Yamashita et al, 1998) in contrast to other picornaviruses (Hellen and Wimmer, 1992). Also the 2A and L protein of Aichi virus have no protease or autocatalytic motifs as documented for other picornaviruses and their function remains unknown (Yamashita et al, 1998). In dogs, the first kobuviruses were described in 2011.…”

Human coronaviruses are uncommon in patients with gastrointestinal illness

“…2 Other viruses implicated in human gastroenteritis include coronaviruses, toroviruses, human bocaviruses, picornoviruses, pestivirus, and breda virus. [3][4][5][6][7][8] However, the role of these viruses in gastrointestinal illness remains unclear. Even with sensitive molecular diagnostic techniques, a substantial percentage of gastrointestinal illness has no identifiable etiology.…”

Novel picornavirus in domestic rabbits (Oryctolagus cuniculus var. domestica)

“…Kobuviruses have a wide range of host species identified from mammalian hosts, e.g. human (Yamashita et al, 1998), canine (Li et al, 2011), feline (Chung et al, 2013), murine (Phan et al, 2011), bovine (Yamashita et al, 2003), ovine (Reuter et al, 2010), ferret (Smits et al, 2013), porcine (Reuter et al, 2009), and caprine (Oem et al, 2014) and was also found in the faeces from a carnivorous bird, the European roller . In addition, kobuviruses are also detected in environmental samples (Ng et al, 2012).…”