No 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.

composed of a single strand of ribonucleic acid (RNA) and a single peptide of molecular weight 59,500, hereby designated protein N.

We have established a method of quantitative detection and rapid identification of human adenoviruses (hAdVs). Using LightCycler PCR with a primer set, we were able to amplify 554 bp of the hexon gene from each of 51 prototype strains of hAdVs. The sensitivity of LightCycler PCR was 10 copies of hAdV DNA/reaction. When LightCycler PCR was performed using a set of primers, hAdV was positive for 74.4% (99 of 133) of conjunctivitis patients and for 27.3% (81 of 297) of respiratory infection patients. We also attempted to measure hAdV in the potentially contaminated eye drops used by patients, detecting 5.4 ؋ 10 2 to 1.6 ؋ 10 Human adenoviruses (hAdVs) of the genus Mastadenovirus of the family Adenoviridae infect billions of people worldwide and cause various diseases such as conjunctivitis, respiratory infectious disease, diarrhea in infants and young children, hemorrhagic cystitis, etc. (1,8,33,39,40). Most of these diseases heal naturally, but sometimes the infection may also provoke serious illnesses such as pneumonia caused by AdV type 7 (AdV-7) or epidemic keratoconjunctivitis (EKC) due to . These more serious outcomes occur in all age groups and can possibly trigger highly contagious nosocomial infections (5,6,19,27,42). Therefore, it is important to establish a rapid method of virological diagnosis. Furthermore, hAdV infection in immunosuppressed patients, such as graft recipients and immunodeficient patients including those with AIDS, has been a major problem in recent years and has been lethal in many cases (7,9,10,17,23,40,41). Nosocomial infection is also a serious problem which may require restriction of hospitalization and closing of hospital wards (15). Therefore, it is essential to monitor these viruses, and a rapid method of identifying serotypes is urgently needed.hAdVs were initially grouped into six subgenera (A to F) on the basis of several biochemical and biophysical criteria (1, 39). In 1999, reclassification on the basis of nucleotide and deduced amino acid sequences was approved by the International Committee on Taxonomy of Viruses; under this reclassification, the 51 serotypes of hAdVs in the genus Mastadenovirus were grouped into six species, hAdV-A to hAdV-F (38). Virus isolation followed by a neutralization test has been the standard method of serotyping (39); however, these procedures are complicated and time-consuming, and the standardized antisera are in limited supply. Recent advances in amplifying hAdV genes and decoding nucleotide sequences have allowed us to develop a PCR-restriction fragment length polymorphism method with which we have succeeded in distinguishing 14 hAdVs including AdV-3, -4, -8, -19a, and -37, all of which cause eye infections in humans (31). Furthermore, nucleotide sequence analysis of the partial hexon genes (916 bp) of all 33 prototype strains in hAdV-D and hAdV-E allowed us to construct a database for the phylogeny-based identification of hAdVs from patients with conjunctivitis (34). However, this method requires several overlapping sequences to determine 9...

In 2000, we encountered cases of nosocomial infections with epidemic keratoconjunctivitis (EKC) at a university hospital in Kobe, in the western part of Japan. Two human adenovirus (HAdV) strains, Kobe-H and Kobe-S, were isolated from patients with nosocomial EKC infection. They were untypeable by existing neutralizing antisera; however, the isolate was neutralized with homologous antisera. We then encountered several cases of EKC due to nosocomial infections in eye clinics in different parts of Japan. A total of 80 HAdVs were isolated from patients with EKC at eight different hospitals. The partial hexon gene sequences of the isolates were determined and compared to those of the prototype strains of 51 serotypes. All isolates had identical partial hexon nucleotide sequences. Phylogenetic analysis classified these isolates into species of HAdV-D. The isolates showed 93.9 to 96.7% nucleotide identity with HAdV-D prototype strains, while all 32 HAdV-D prototype strains ranged from 93.2 to 99.2% identity. The sequences of the loop 2 and fiber knob regions from the representative strain, Kobe-H, were dissimilar in all prototype strains of 51 serotypes. We believe that this virus is a novel serotype of HAdV that causes EKC.