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

HUMAN ADENOVIRUS TYPE 4 COMPRISES TWO MAJOR PHYLOGROUPS WITH DISTINCT REPLICATIVE FITNESS AND VIRULENCE PHENOTYPES

Human adenovirus type 4 (HAdV-E4) is the only type (and serotype) classified within species Human mastadenovirus E that has been isolated from a human host to the present. Recent phylogenetic analysis of whole genome sequences of strains representing the spectrum of intratypic genetic diversity described to date identified two major evolutionary lineages designated phylogroups (PG) I, and II, and validated the early clustering of HAdV-E4 genomic variants into two major groups by low resolution restriction fragment length polymorphism analysis. In this study we expanded our original analysis of intra- and inter-PG genetic variability, and used a panel of viruses representative of the spectrum of genetic diversity described for HAdV-E4 to examine the magnitude of inter- and intra-PG phenotypic diversity using an array of cell-based assays and a cotton rat model of HAdV respiratory infection. Our proteotyping of HAdV-E strains using concatenated protein sequences in selected coding regions including E1A, E1B-19K and -55K, DNA polymerase, L4-100K, various E3 proteins, and E4-34K confirmed that the two clades encode distinct variants/proteotypes at most of these loci. Our in vitro and in vivo studies demonstrated that PG I and PG II differ in their growth, spread, and cell killing phenotypes in cell culture and in their pulmonary pathogenic phenotypes. Surprisingly, the differences in replicative fitness documented in vitro between PGs did not correlate with the differences in virulence observed in the cotton rat model. This body of work is the first reporting phenotypic correlates of naturally occurring intratypic genetic variability for HAdV-E4. IMPORTANCE Human adenovirus type 4 (HAdV-E4) is a prevalent causative agent of acute respiratory illness of variable severity and of conjunctivitis and comprises two major phylogroups that carry distinct coding variations in proteins involved in viral replication and modulation of host responses to infection. Our data show that PG I and PG II are intrinsically different regarding their ability to grow and spread in culture and to cause pulmonary disease in cotton rats. This is the first report of phenotypic divergence among naturally occurring known genetic variants of a HAdV type of medical importance. This research reveals readily detectable phenotypic differences between strains representing phylogroups I and II, and it introduces a unique experimental system for the elucidation of the genetic basis of adenovirus fitness and virulence and thus for increasing our understanding of the implications of intratypic genetic diversity in the presentation and course of HAdV-E4-associated disease.

Molecular Identification of Adenoviral Conjunctivitis in Turkey

Purpose.

The aim of the study was isolation of adenoviruses by cell culture and identification using polymerase chain reaction (PCR) and phylogenetic analyses in patients clinically diagnosed with viral conjunctivitis in Ankara, Turkey.

Methods.

Conjunctival swabs from 34 patients with acute conjunctivitis were tested using cell culture isolation and PCR for adenovirus detection. PCR-positive samples were sequenced and typed.

Results.

The positive results of adenovirus were 26.5% (9 of 34) by the PCR method and 20.6% by culture isolation. Nine samples positive at PCR were identified by phylogenetic analyses as human adenovirus 8 (HAdV-8) (4 of 9), HAdV-3 (3 of 9), HAdV-4 (1 of 9), and HAdV-B (1 of 9).

Conclusions.

Our study showed types of adenoviruses in patients with ocular infection that occurred in this region of Turkey for the first time. Furthermore, sequence-based typing method is an efficient, accurate, and rapid means of diagnosis and typing of the adenovirus and has significant clinical and epidemiologic implications. HAdV-8 was major type for acute conjunctivitis in Ankara, Turkey. Further studies are required to reveal the major types of HAdVs that cause ocular diseases in this region of the world.

Secular trend of genome types of respiratory adenovirus type 3 during 1983-2005: a study from Taiwan

Genome type analysis of adenovirus type 3 (Ad3) in Taiwan identified four types (Ad3a, Ad3a2, Ad3a1, Ad3-7) during 1983-2005. Ad3a was the major type during 1983-1999, while Ad3a2 was the predominant type from 2001 to 2005. Phylogenetic analysis of the hexon gene of 23 isolates revealed that most Ad3a2 and Ad3-7 isolates belonged to one cluster, and most Ad3a isolates to the other cluster. The clinical manifestations included respiratory tract infections, acute gastroenteritis, hand-foot-and-mouth disease, febrile convulsion and pharyngoconjunctival fever. In conclusion, Ad3a2 has replaced Ad3a as the most common genome type in Taiwan since 2001.

Molecular epidemiology of adenovirus strains isolated from patients with ocular disease in the area of Thessaloniki, Greece (1998-2002)

Thirty strains of adenovirus (Ads) associated with ocular disease have been isolated over a period of 4 years in Thessaloniki, Northern Greece. Eleven strains were isolated from sporadic patients with conjunctivitis or keratoconjunctivitis in Thessaloniki city between 1998 and 2000. Nineteen strains were isolated from patients with keratoconjunctivitis during an outbreak of Ads in the area of Thessaloniki (Thessaloniki and Serres cities) in 2002. PCR-sequence method using primers targeted against the hypervariable regions (HVRs) of hexon gene, as well as the neutralization test were used for typing the Ad isolates and assessing a possible relation among these strains, and their genetic variability. Ad4 with very close homology to variant Z-G 95-873 was the most frequent genotype causing sporadic conjunctivitis over a period of 4 years. Two other strains, one Ad2, and one Ad3 were similar to the prototype ones, and a third one shows close homology to the variant of prototype Ad15, the Morrison strain. The genome typing of twenty two Ad8 isolates showed very close homology in their amino acid and nucleotide sequences to the variant of Ad8, strain 1127 (accession no. X74663). Four were isolated from patients with keratoconjunctivitis in 1998, 1999, 2000 and 18 during the outbreak in 2002. As far as strain 1127 is concerned, all the Ad8 isolates showed the same changes in the HVR 1 and HVR 2 except one isolate in 1998, which showed some changes outside the HVRs. During the outbreak of Ad8 keratoconjunctivitis, it was not possible to identify the exact source of infection (nosocomial or/and outpatients). Finally, Ad4 variant Z-G 95-873 and Ad8 which is closely related to the strain 1127, were found to be the predominant adenoviruses circulating in Northern Greece during 1998-2002.

New genome type of adenovirus serotype 4 caused nosocomial infections associated with epidemic conjunctivitis in Japan

Human adenovirus type 4 is one of the major serotypes isolated from patients with adenoviral conjunctivitis. In 2001 we encountered nosocomial infections with epidemic conjunctivitis in the ophthalmology ward of one hospital in Sapporo, which is in the northern part of Japan. Adenoviruses were isolated from the patients with this nosocomial infection and identified as adenovirus type 4 (AdV-4) by a neutralization test with serotype-specific antiserum. When the cleavage patterns of the isolates were compared with the full viral genome with BamHI and SmaI, the cleavage patterns of the isolates were shown to be different from those of AdV-4p and other previously known AdV-4 variants. The nucleotide sequences of the fiber gene of the isolates showed the highest homologies (94.3%) with AdV-4 among the nucleotide sequences available from GenBank and formed a monophyletic cluster along with the prototype strain of AdV-4. The isolates, however, were located in a different lineage from those of AdV-4p and the AdV-4 variant from the sporadic infections. We conclude that the nosocomial infection that appeared in 2001 was caused by a new genome type of AdV-4, which was designated AdV-4c.

A twenty-one year surveillance of adenoviral conjunctivitis in Sapporo, Japan

We have studied the clinicoetiological, serological, and molecular epidemiological features of adenoviral conjunctivitis under the auspices of the nationwide surveillance project in Sapporo, located in northern Japan. We were able to analyze the results of 1,454 cases of adenoviral, herpetic, and chlamydial conjunctivitis. We found that adenonovirus serotypes 8, 19, and 37 caused severe conjunctivitis without systemic symptoms, whereas serotypes Ad3, Ad7, and Ad11 caused mild conjunctivitis with systemic involvement. Ad4 showed a broad range of symptoms, from PCF to EKC. Adenoviral conjunctivitis had seasonal outbreaks in the summer in association with adequate temperature and humidity in Sapporo. Neutralization antibodies against Ad8, Ad19, and Ad37 were detected in fewer than 20% of cases, and so the incidence of epidemics with these serotypes may rise in the coming years. The main genome types of adenovirus in Sapporo were Ad4a, Ad8e, Ad19a, Ad19b, and Ad37p, a, and b.

Genome analysis of adenovirus type 3 isolated in Japan

Adenovirus type 3 (Ad3) isolates, isolated from 45 patients with acute conjunctivitis during the year 1990 in Japan, were studied by DNA restriction enzyme analysis with restriction endonucleases recognizing 6-bp sequences (BamHI, SmaI, HindIII, BglII) and endonucleases recognizing 5- or 4-bp sequences (HinfI and TaqI). All 45 isolates of Ad3 were identified as the genome type Ad3f by six endonucleases. They were further classified into three varieties by HinfI, varieties H1 (87.5%), H2 (8.9%), and H3 (2.2%), and into five varieties by TaqI, varieties T1 (75.6%), T2 (13.3%), T3 (2.2%), T4 (4.5%), and T5 (8.9%). The use of HinfI and TaqI was sufficient to distinguish six subgenome types: types Ad3fH1T1, Ad3fH1T2, Ad3fH1T4, Ad3fH1T5, Ad3fH2T1, and Ad3fH3T3. Among them, Ad3fH1T1 was predominant in areas where the virus is epidemic. The study showed that the same Ad3 genome type, genome type Ad3f, caused acute viral conjunctivitis even in different areas in Japan. The source and the route of infection were suggested to be common in areas where the virus is epidemic.