Genome analysis of adenovirus type 3 isolated in Japan

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.

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 human adenovirus isolated from children hospitalized with acute respiratory infection in São Paulo, Brazil

In a study of acute respiratory disease, two collections of nasopharyngeal aspirates (NPA) were obtained from children hospitalized at the Pediatric Clinic of the University Hospital, São Paulo, in 1995 and 2000. Adenovirus was detected in 33 (8.2%) of 401 children followed. These viruses were isolated in HEp-2, HEK-293, or NCI-H292 cells and serotyped by neutralization. The genome types were determined after restriction analyses of the genomic DNA extracted from infected cells. Nineteen isolates were characterized as Human adenovirus B, genome types HAdV-3a, HAdV-7h, and HAdV-7h1; 11 as Human adenovirus C, genome types HAdV-1D10, HAdV-2D25, HAdV-5D2, and HAdV-6D3. Our findings show that species C adenoviruses present an endemic infection pattern, with co-circulation of different serotypes and genome types; no new genomic variant was observed. Species B adenoviruses showed epidemic infection patterns, with shifts in the predominant genome type. The isolates from 1995 belong to genome type 7h, or the variant 7h1, with a clear substitution of the type 7b, prevalent in São Paulo for more then 10 years. In 2000, the variant 7h1 predominated and the emergence of the type 3a was observed. Almost 10 years passed between the identification of HAdV-7h in Argentina and its detection in São Paulo. The geographic isolation of these two countries was reduced by the increase in population mobility due to growing commercial relationships.

Comparative genomic analysis of two strains of human adenovirus type 3 isolated from children with acute respiratory infection in southern China

Human adenovirus type 3 (HAdV-3) is a causative agent of acute respiratory disease, which is prevalent throughout the world, especially in Asia. Here, the complete genome sequences of two field strains of HAdV-3 (strains GZ1 and GZ2) isolated from children with acute respiratory infection in southern China are reported (GenBank accession nos DQ099432 and DQ105654, respectively). The genomes were 35,273 bp (GZ1) and 35,269 bp (GZ2) and both had a G+C content of 51 mol%. They shared 99% nucleotide identity and the four early and five late regions that are characteristic of human adenoviruses. Thirty-nine protein- and two RNA-coding sequences were identified in the genome sequences of both strains. Protein pX had a predicted molecular mass of 8.3 kDa in strain GZ1; this was lower (7.6 kDa) in strain GZ2. Both strains contained 10 short inverted repeats, in addition to their inverted terminal repeats (111 bp). Comparative whole-genome analysis revealed 93 mismatches and four insertions/deletions between the two strains. Strain GZ1 infection produced a typical cytopathic effect, whereas strain GZ2 did not; non-synonymous substitutions in proteins of GZ2 may be responsible for this difference.

Genome type analysis of adenovirus types 3 and 7 isolated during successive outbreaks of lower respiratory tract infections in children

Adenovirus is an important cause of respiratory infections in infants and children. Fifty-one serotypes have been identified, and adenovirus type 3 (Ad3) and Ad7 have often been associated with outbreaks of severe respiratory tract infections. Each serotype can be further divided into genome types based on the patterns of digestion of their DNAs with restriction enzymes. DNA restriction analysis was performed with 56 strains of Ad3 and 98 strains of Ad7 by using 12 restriction enzymes recognizing 6 bp (BamHI, BclI, BglI, BglII, BstEII, EcoRI, HindIII, HpaI, SalI, SmaI, XbaI, and XhoI). The virus strains were isolated during outbreaks of lower respiratory tract infections in children during an 11-year period from 1990 to 2000 in Seoul, Korea. Among the Ad3 strains, seven genome types were identified; Ad3a and six novel types (Ad3a13, Ad3a14, Ad3a15, Ad3a16, Ad3a17, and Ad3a18). Multiple genome types cocirculated during outbreaks, and some of these were isolated during the 11-year observation period, while others were restricted to particular outbreaks. For Ad7, two genome types, Ad7d and Ad7l, the latter of which is a novel genome type, were identified. A shift in genome types occurred from Ad7d to Ad7l during successive outbreaks. Mortality was 3.6% among children with Ad3 infections and 18% among children infected with either of the Ad7 genome types. In conclusion, the data confirm that Ad3 genome types are more diverse than those of Ad7 and suggest that shifts of genome types may occur during successive outbreaks of Ad3 and Ad7.