Genome variants of human adenovirus types 40 and 41 (subgroup F) in Japan

Adenovirus genome types isolated from stools of children with gastroenteritis in São Paulo, Brazil

In a prospective one-year study of acute gastroenteritis in hospitalized children less than 2 years of age, in São Paulo (Brazil), adenoviruses were detected by specific enzyme immunoassay (El-ARA) in 7 of 67 (10%) ill children and in 9 of 79 (11.4%) controls. They were the sole recognizable agent of diarrhea in 6 ill children. In another child these viruses were detected in a dual infection with astrovirus. Enteric adenoviruses (Ad40/41) were the most common serotypes detected in children with diarrhea (3/7) and Ad7 the serotype most detected in the controls (5/9), associated with lower respiratory tract infection. Thirteen adenovirus strains, isolated in HEp2 or HEK-293 cells, were characterized by seroneutralization and restriction enzyme analysis. The established adenoviruses were typed as AV-7-D5 (five associated to lower respiratory tract infection and one to diarrhea), AV-1-D10 (one diarrhea case), AV-31-D2 (two controls with respiratory infection), and two isolates as AV-12-D7, a new genome type. One subgenus D isolate, serotype 28, with restriction patterns different from those of the prototype, remained untyped. Only one enteric adenovirus could be typed. The restriction patterns of this isolated were similar to those of the prototype AV-41-D1. The genome type of the other three enteric adenoviruses could not be determined.

Identification of adenoviruses in faeces from patients with diarrhoea at the Hospitals for Sick Children, London, 1989-1992

Faecal samples from 137 patients that had been shown to contain adenoviruses by electron microscopy were identified in a series of enzyme immunoassays (EIA) using a single monoclonal antibody (Mab) to adenovirus 40 and four different Mabs to adenovirus 41. Adenoviruses were partially characterised by restriction enzyme analysis (REA) of DNA extracts using SmaI. Samples were also run in a commercial EIA (Adenovirus IDEIA; Dako, Ltd.) which detects group antigen. The majority (84%) of adenoviruses were subgenus F: adenovirus type 41, 87 (64%) and adenovirus type 40, 28 (20.4%). Subgenus A viruses were identified in ten, (7%) patients, eight were type 31, and two type 12. The adeno IDEIA test was sensitive and specific, detecting 127 of 131 positives and giving no false-positive results with other enteric viruses. Use of monoclonal-based EIAs showed significant differences depending on which adeno 41 Mab was used, although the restriction patterns obtained using SmaI appeared to be identical for 66 of 69 samples that produced recognisable bands. The Mab that performed best, M 4.3.1, was raised against strains obtained from children in England and detected 83 of 84 (99%) of the adenovirus 41 samples tested. In contrast Mab JH/41 raised against the prototype strain of adenovirus 41 (Tak) detected only 69 of 87 (79%).

Enteric adenovirus type 41 isolates: cloning, physical maps and diversity in restriction enzyme cleavage pattern

Adenovirus (Ad) type 40 and 41 DNAs were directly extracted from stool specimens of children with gastroenteritis. Two new strains of Ad41, Sanekata and Ehime strain, were cloned and their restriction maps were constructed. The left terminal end of the cloned Ad41 genome, EcoRI-E fragment of the Sanekata strain and EcoRI-F fragment of the Ehime strain, had transforming ability in rat 3Y1 cells. Only one of the 35 isolates of Ad40 tested showed a different restriction profile, while three different restriction profiles were found in DNAs from Ad41 isolates.

Restriction analysis of the prototype strain of enteric adenovirus type 41 using exonuclease III

Enteric adenoviruses 40 and 41 (Ad40 and Ad41) are a prominent cause of gastroenteritis in young children. Diagnosis of these enteric types by conventional means is complicated by their fastidious growth characteristics. Enteric adenovirus growth was enhanced by cocultivation. Typing of enteric isolates currently entails analysis of the extracted viral DNA with restriction enzymes. Restriction endonuclease fragments of the Ad41 strain Tak genome were ordered by (i) double digestion, (ii) release of restriction fragments from plasmids containing 84% of the Ad41 genome in EcoRI fragments A, B and C, (iii) hybridization of Southern blotted Ad41 fragments with EcoRI fragment containing plasmids and various segments of the Ad2 genome, (iv) sequential reduction of the genome beginning with terminal restriction fragments with exonuclease III and S1 nuclease. The termini of adenovirus genomes are difficult to clone and the use of exonuclease III is a useful alternative to conventional restriction mapping. DNA restriction patterns, fragment sizes and restriction maps of the Ad4 1 strain Tak with enzymes BamHI, BglII, ClaI, EcoRI, HindIII, PstI, SalI, SmaI and XhoI are presented. Prototype strain restriction maps should enable better understanding of adenovirus type 41 and its epidemiology.

Clinical features of enteric adenovirus infection in infants

During the period December 1984 to October 1988, adenoviruses (Ads) were isolated on 119 occasions (1.6%) from stool samples of patients with gastroenteritis. By DNA restriction analysis, 85 enteric adenoviruses (EAds) were identified. Sixty-seven patients with these infections were studied, of whom 18 had Ad40, 30 had Ad41 and 19 had untyped Ad infections. The incidence of Ad infection was high in children between 6 and 11 months of age. The illness was characterized by watery diarrhea (whitish in one third of patients), continuing for a mean of 4.5 days, and vomiting, which occurred more often in patients with EAds than in other types of infection. Diarrhea, fever and vomiting were seen significantly more frequently in patients with Ad40 than in Ad41 infection. Diarrhea and vomiting were also seen significantly more frequently in patients with EAds than in Ads infection. Diarrhea, fever and vomiting were observed more frequently in patients with rotavirus than EAds infection.

Changes in subgenome types of adenovirus type 4 isolated from patients with ocular disease between 1985 and 1989 in Sapporo, Japan

A total of 122 adenovirus type 4 (Ad4) strains isolated from patients with epidemic keratoconjunctivitis at an eye clinic in Sapporo, Japan, from 1985 to 1989 were identified as Ad4a. By the use of HinfI and TaqI restriction endonucleases, these Ad4a strains were classified into 12 subgenome types. During this observation period, two epidemics of Ad4 infection relating to epidemic keratoconjunctivitis occurred. During the Ad4a epidemic in 1985, three subgenome types became predominant successively. However, except for one strain, the prevalent strains isolated during the epidemic of Ad4a in 1988 all belonged to a single subgenome type. In the years when an Ad4a epidemic was not observed, such Ad4a strains were new or previous subgenome types. The prevalent subgenome types tended to change within several years.

A rational system for classifying and denominating adenovirus genome types

We propose to classify "genome types" of human adenoviruses in the same way as the "genomic clusters" defined by Li and Wadell, i.e. groups of closely related DNA variants of a given serotype named by the use of indices, P (standing for prototype) a, b etc. Variants within the genome type are named by letter-number indices (p1, p2; a1, a2 etc.). The percentage of comigrating restriction fragments and common restriction sites is significantly higher in variants than between genome types. The new naming system is applicable to adenoviruses from 5 subgenera, but requires additional work for subgenus C strains. Renaming is required mainly for adenovirus 7.

Epidemiology of enteric adenoviruses 40 and 41 in acute gastroenteritis in infants and young children in the Tokyo area

82/2,223 stool specimens, collected 1982-1988, from children with enteritis (3.7%) were found to contain adenoviruses; 17 adenovirus-positive samples were provided from other institutes. 89 adenoviruses were isolated in Graham 293 cells from these 99 specimens and were typed by DNA restriction enzyme analysis with Sma I. 37 strains were typed as adenovirus 40 (AD40), and 37 strains as adenovirus 41 (Ad41). Although most strains had the same DNA profiles, a few strains had 3 kinds of different electropherotypes generated by Sma I. Five strains were identified as adenovirus 31. The remaining 10 strains were adenovirus 1 (2 strains), adenovirus 2 (3 strains), adenovirus 3 (1 strain), adenovirus 5 (1 strain), and a non-classified adenovirus (3 strains). Ad40 and Ad41 infections were found throughout the year, but peaked between September and November. 80% of the children with adenovirus infections were less than or equal to 2 years of age. The highest incidence of diarrhea caused by Ad40 or Ad41 was in 6-11 months old children. 1982-1984, the rate of Ad40 infection was 91.7%, while the rate of Ad41 infection was only 8.3%. The prevalence of Ad40 infection gradually diminished from 1985. During 1987 and 1988 the reverse ratios, 20.6% and 79.4%, respectively, of Ad40 and Ad41 infections were observed. Thereafter, Ad41 infection became predominant.

Prevalent enteric adenovirus variant not detected by commercial monoclonal antibody enzyme immunoassay

A commercial monoclonal antibody enzyme immunoassay for the detection of enteric adenovirus type 40 and 41 (Ad40 and Ad41) in stool specimens was evaluated. Twenty-one stool specimens from children with gastroenteritis, with adenovirus particles visible by electron microscopy, and reference strains Ad40 Dugan and Ad41 Tak were tested by Ad40- and Ad41-specific and adenovirus group-reactive immunoassays. All stool specimens tested positive in the group-reactive immunoassay. However, only six specimens, containing isolates of Ad40 strain Hovi-X, an Ad40 genomic variant, and Ad41 strain Tak, reacted with the specific immunoassay, besides the reference strains. Fifteen stool specimens determined by restriction analysis to contain a genomic variant of Ad41 were negative by specific immunoassay. The positions of restriction site differences from the prototype strain Ad41 Tak were analyzed, and four mutations were mapped within the hexon gene; two others may occur in the fiber gene. The Ad41 genomic variant not detected by the enteric test is presently the most frequent cause of local adenoviral gastroenteritis. Highly specific monoclonal antibodies can fail to detect genomic variants of enteric adenoviruses, probably because of alteration of external neutralizable epitopes under immunological pressure to vary.

Analysis with restriction endonucleases recognizing 4- or 5-base-pair sequences of human adenovirus type 3 isolated from ocular diseases in Sapporo, Japan

A total of 49 adenovirus type 3 (Ad3) strains from patients with epidemic keratoconjunctivitis at an eye clinic in Sapporo, Japan, from 1983 to 1986 were classified into either genome type Ad3f (26 strains) or Ad3g (23 strains). By the use of Hinf1 and TaqI restriction endonucleases, they were classified into 11 and 3 subgenome types, respectively. During this observation period, two epidemics of Ad3 infection relating to epidemic keratoconjunctivitis occurred. The prevalent Ad3g strains isolated during the epidemic in 1983 belonged to a single subgenome type. However, in the course of the Ad3f epidemic in 1986, alteration of one subgenome type of the prevalent strain to a different subgenome type which was presumed to be a derivative of the former was observed. In the years in which only a few Ad3 strains were isolated, such Ad3f strains were classified into different subgenome types. However, all Ad3g strains except two belonged to the same subgenome type.

Enzyme-linked immunosorbent assay employing monoclonal antibodies for direct identification of enteric adenoviruses (Ad40,41) in feces

For detection and identification of enteric adenovirus (Ad) types 40 and 41 in stool specimens, enzyme-linked immunosorbent assay (ELISA) was developed with the use of three monoclonal antibodies: Ad group-specific, Ad40 type-specific, and Ad41 type-specific antibodies. Of 860 fecal samples from patients with acute gastroenteritis, 44 strains of Ad were isolated using Graham 293 cell cultures. Of these isolates, 20 were typed as Ad40, 18 were Ad41, and 6 were other Ads by neutralization tests with cell cultures. Results of the ELISA tests on these 860 fecal samples resulted in good agreement to those with the cell culture method. The ELISA tests using Ad type-specific monoclonal antibodies proved to be a specific and rapid technique for laboratory diagnosis of acute gastroenteritis caused by enteric Ads.