Genomic comparison of adenovirus type 3 isolates from patients with acute conjunctivitis in Japan, Australia, and the Philippines

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.

Genomic diversity of human adenovirus type 3 isolated in Fukui, Japan over a 24-year period

Recently, human adenovirus type 3 (HAdV-3) has become the most isolated HAdV worldwide. Restriction endonuclease analysis of globally isolated strains of HAdV-3 has uncovered 51 genome types to date. Information on the genome type is important to the epidemiological study of HAdV-3. In this study, analysis of 75 isolates of HAdV- 3 collected over a 24-year period in Fukui revealed: (1) the emergence of three novel genome types (HAdV-3a52, HAdV-3a53 and HAdV-3a54) and two known genome types (HAdV-3a and HAdV-3a54); (2) the spectrum of diseases caused by individual genome types and their major involvement in the paediatric age population; and (3) the co-circulation and replacement of genome types as a usual phenomenon. The rising number of HAdV-3 genome types indicates that the genetic variation of HAdV-3 is more than other HAdVs. Considering the clinical importance of HAdV-3 infection, its genetic diversity underscores the need for its continuous surveillance and genetic characterization.

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.

Emergent US adenovirus 3 strains associated with an epidemic and serious disease

BACKGROUND

Adenovirus type 3 (HAdV3) is one of the most prevalent serotypes detected globally. Variants of HAdV3 have been associated with outbreaks of severe disease.

OBJECTIVES

To better understand genetic diversity of circulating HAdV3s and examine risk factors for severe disease.

STUDY DESIGN

Restriction enzyme analysis for genomic characterization of clinical HAdV3 isolates detected by 15 collaborative US laboratories during the period July 2004 to May 2007. Multivariate modeling was employed for statistical analyses.

RESULTS

The most common HAdV3 types of 516 isolates studied were HAdV3a2 (36.9%), HAdV3a50 (27.1%), HAdV3a51 (18.0%), and HAdV3a17 (4.6%). Non-HAdV3a genome types were rare (1.2%). HAdV3a50 and HAdV3a51 are newly described variants which became more prevalent in 2006 and 2007 and have been associated with at least one epidemic. Their uniqueness was determined by specific banding profiles generated by digests with endonucleases BclI, BglII, and HindIII. Multivariable risk factor modeling demonstrated that children under 2 years of age (OR=2.7; 95%CI 1.6-4.6), persons with chronic disease (OR=5.1; 95%CI 2.6-9.8), persons infected with HAdV3a2 (OR=3.0; 95%CI 1.5-6.0), with HAdV3a50 (OR=2.5; 95%CI 1.2-5.2), or with multiple or rare strains (OR=2.8; 95%CI 1.3-6.5) were at increased risk of severe HAdV3 clinical disease.

CONCLUSIONS

In the study period considerable genetic diversity was found among US clinical HAdV3 strains. Novel variants emerged and became prevalent. One such emergent strain may be associated with more severe clinical disease.

Adenovirus type 3 outbreak in connecticut associated with a novel variant

An adenovirus outbreak occurred in New Haven, Connecticut in 2006-2007. Molecular typing revealed a twofold increase in adenovirus type 3 infections. Restriction enzyme analysis (REA) indicated that the CT outbreak was largely due to a marked increase in the novel Ad3a51 strain. This outbreak represents the first detection of Ad3a51 in the United States. While most infections were mild, children under 3 were at increased risk for severe disease and one patient with underlying disease died.

A community-derived outbreak of adenovirus type 3 in children in Taiwan between 2004 and 2005

An outbreak of respiratory adenovirus infection in children was observed in northern Taiwan between November 2004 and February 2005. Using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to determine the serotype(s) of 172 adenovirus isolates in the outbreak period, we found that adenovirus type 3 (Ad3) was the predominant type (87.2%), followed by Ad2 (6.4%), Ad1 (4.1%), Ad7 (1.2%), Ad4 (0.6%), and Ad5 (0.6%). The genotype of Ad3 was analyzed for 15 isolates from the outbreak period by RFLP of the full-length genome. All these isolates belonged to genotype Ad3a2. Compared with the Ad3-infected patients in the baseline period, a significantly higher proportion of Ad3-infected patients in the outbreak period had severe infections (58.0% vs. 40.2%, P = 0.01), which included bronchopneumonia (28.7%), exudative tonsillitis (24.1%), and tonsillitis (16.1%). Moreover, patients with severe infections were significantly younger than those without (4.10 vs. 8.15 years, P < 0.001). In summary, our study demonstrated that Ad3 was the predominant serotype responsible for the respiratory adenovirus outbreak in northern Taiwan during 2004-2005 and was associated with severe infections in the outbreak period.

Outbreak of human adenovirus type 3 infection in a pediatric long-term care facility--Illinois, 2005

BACKGROUND

Human adenovirus type 3 (HAdV-3) causes severe respiratory illness in children, but outbreaks in long-term care facilities have not been frequently reported. We describe an outbreak of HAdV-3 infection in a long-term care facility for children with severe neurologic impairment, where only 3 of 63 residents were ambulatory.

METHODS

A clinical case of HAdV-3 was defined as fever (temperature, > or = 38.0 degrees C) and either a worsening of respiratory symptoms or conjunctivitis in a resident, with illness onset from June through August 2005. We reviewed medical records; conducted surveillance for fever, conjunctivitis, and respiratory symptoms; and collected nasopharyngeal and conjunctival specimens from symptomatic residents. Specimens were cultured in HAdV-permissive cell lines or were analyzed by HAdV-specific polymerase chain reaction assay.

RESULTS

Thirty-five (56%) of 63 residents had illnesses that met the case definition; 17 patients (49%) were admitted to intensive care units, and 2 (6%) died. Patients were hospitalized in the intensive care unit for a total of 233 patient-days. Illness onset dates ranged from 1 June through 24 August 2005. Thirty-two patients (91%) had respiratory infection, and 3 (9%) had conjunctivitis. HAdV was identified by culture or PCR in 20 patients. Nine isolates were characterized as HAdV-3 genome type a2.

CONCLUSIONS

Considering the limited mobility of residents and their reliance on respiratory care, transmission of HAdV-3 infection during this outbreak likely occurred through respiratory care provided by staff. In environments where patients with susceptible underlying conditions reside, HAdV infection should be considered when patients are identified with worsening respiratory disease, and rapid diagnostic tests for HAdV infection should be readily available to help identify and curtail the spread of this pathogen.

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.

Four new genotypes of adenovirus type 3 isolated from patients with conjunctivitis in Japan

Adenovirus type 3 (Ad3) was the most frequently isolated serotype from patients with conjunctivitis during the period from 1989 to 1991 in Japan. All Ad3 strains isolated in 1990 had an identical genotype, Ad3f. However, in 1992, the predominant serotype was replaced by Ad4. The genome type was examined to determine whether genetic changes existed in Ad3 isolates in 1992. Ad3 isolated from 55 patients with acute conjunctivitis during the period from June 1992 to February 1993 in Japan was assessed by genome typing with restriction endonucleases BamH I, Bgl II, Hind III, and Sma I recognizing 6-base-pair sequences. The emergence of four new genotypes of Ad3 was identified; one with a new Bam HI site (one isolate), one with a new Bgl II site (two isolates), one with a new Hind III site (three isolates) and one with a new Sma I site (two isolates). This study demonstrates that the emergence of a new genotype of Ad3 may contribute to the replacement of the predominant serotype associated with adenovirus conjunctivitis in Japan.

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.

Six-year longitudinal analysis of adenovirus type 3 genome types isolated in Yamagata, Japan

Five hundred eighty-seven adenovirus type 3 (Ad3) isolates were established from children with acute respiratory infections (ARI) from 1986 to 1991, in Yamagata, Japan. Ad3 could be found in almost all the months during the 6 years when two epidemics occurred, in 1987 and 1989. A molecular epidemiological study was done on 346 of the 587 isolates, using restriction endonucleases; BamHI, HindIII, SmaI, and BgIII were used. The Ad3 isolates were classified into seven genome types. The genetic differences among the seven genome types were < 0.9%, and their phylogenetic tree, estimated by the neighbor-joining method, correlated highly with their monthly distribution. One genome type predominated for 56 months, while the other six related genome types cocirculated for a short period. These results suggested that the predominant genome type of Ad3 might have been endemically perpetuated in the Yamagata area with minor genomic variations. Furthermore, the outbreaks of Ad3 may have been due not to the appearance of a new genome type but rather to the endemic genome type.

Restriction site mapping of four genome types of adenovirus types 3 and 7 isolated in South America

New genome types of Ad3 and Ad7 were found among adenovirus (Ad) strains isolated from stools of children during epidemiological surveys made in São Paulo, Brazil, and Buenos Aires, Argentina. These were characterized by DNA analysis with 11 restriction endonucleases and showed a number of new restriction patterns, notably for BamHI, BcII, BgIII, HindIII, KpnI, and SmaI. Restriction maps of the genome types, named Ad3e1, Ad3e2, Ad3h, and Ad7h, were constructed and compared with those of Ad3p and Ad7p.

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.

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.