Genome analysis of South American adenovirus strains of serotype 7 collected over a 7-year period

Adenovirus: Epidemiology, Global Spread of Novel Types, and Approach to Treatment

Adenoviruses (AdVs) are DNA viruses that typically cause mild infections involving the upper or lower respiratory tract, gastrointestinal tract, or conjunctiva. Rare manifestations of AdV infections include hemorrhagic cystitis, hepatitis, hemorrhagic colitis, pancreatitis, nephritis, or meningoencephalitis. AdV infections are more common in young children, due to lack of humoral immunity. Epidemics of AdV infection may occur in healthy children or adults in closed or crowded settings (particularly military recruits). The vast majority of cases are self-limited. However, the clinical spectrum is broad and fatalities may occur. Dissemination is more likely in patients with impaired immunity (e.g., organ transplant recipients, human immunodeficiency virus infection). Fatality rates for untreated severe AdV pneumonia or disseminated disease may exceed 50%. More than 100 genotypes and 52 serotypes of AdV have been identified and classified into seven species designated HAdV-A through -G. Different types display different tissue tropisms that correlate with clinical manifestations of infection. The predominant types circulating at a given time differ among countries or regions, and change over time. Transmission of novel strains between countries or across continents and replacement of dominant viruses by new strains may occur. Treatment of AdV infections is controversial, as prospective, randomized therapeutic trials have not been done. Cidofovir has been the drug of choice for severe AdV infections, but not all patients require treatment. Live oral vaccines are highly efficacious in reducing the risk of respiratory AdV infection and are in routine use in the military in the United States but currently are not available to civilians.

A Mini Review of the Zoonotic Threat Potential of Influenza Viruses, Coronaviruses, Adenoviruses, and Enteroviruses

During the last two decades, scientists have grown increasingly aware that viruses are emerging from the human–animal interface. In particular, respiratory infections are problematic; in early 2003, World Health Organization issued a worldwide alert for a previously unrecognized illness that was subsequently found to be caused by a novel coronavirus [severe acute respiratory syndrome (SARS) virus]. In addition to SARS, other respiratory pathogens have also emerged recently, contributing to the high burden of respiratory tract infection-related morbidity and mortality. Among the recently emerged respiratory pathogens are influenza viruses, coronaviruses, enteroviruses, and adenoviruses. As the genesis of these emerging viruses is not well understood and their detection normally occurs after they have crossed over and adapted to man, ideally, strategies for such novel virus detection should include intensive surveillance at the human–animal interface, particularly if one believes the paradigm that many novel emerging zoonotic viruses first circulate in animal populations and occasionally infect man before they fully adapt to man; early detection at the human–animal interface will provide earlier warning. Here, we review recent emerging virus treats for these four groups of viruses.

Adenovirus: Epidemiology, Global Spread of Novel Serotypes, and Advances in Treatment and Prevention

Adenoviruses (AdVs) are DNA viruses that typically cause mild infections involving the upper or lower respiratory tract, gastrointestinal tract, or conjunctiva. Rare manifestations of AdV infections include hemorrhagic cystitis, hepatitis, hemorrhagic colitis, pancreatitis, nephritis, or meningoencephalitis. AdV infections are more common in young children, due to lack of humoral immunity. Epidemics of AdV infection may occur in healthy children or adults in closed or crowded settings (particularly military recruits). The disease is more severe and dissemination is more likely in patients with impaired immunity (e.g., organ transplant recipients, human immunodeficiency virus infection). Fatality rates for untreated severe AdV pneumonia or disseminated disease may exceed 50%. More than 50 serotypes of AdV have been identified. Different serotypes display different tissue tropisms that correlate with clinical manifestations of infection. The predominant serotypes circulating at a given time differ among countries or regions, and change over time. Transmission of novel strains between countries or across continents and replacement of dominant viruses by new strains may occur. Treatment of AdV infections is controversial, as prospective, randomized therapeutic trials have not been conducted. Cidofovir is the drug of choice for severe AdV infections, but not all patients require treatment. Live oral vaccines are highly efficacious in reducing the risk of respiratory AdV infection and are in routine use in the military in the United States, but currently are not available to civilians.

Outbreak of adenovirus type 55 infection in Israel

BACKGROUND

Different types of adenoviruses are associated with diverse diseases and with varied disease severity. Adenovirus 55 could be associated with severe respiratory infections.

OBJECTIVES

Here, we report on an adenovirus 55 outbreak in two psychiatric institutions in Israel. The objective of this study was to investigate the adenovirus 55 outbreak.

STUDY DESIGN

We studied the clinical parameters of the patients and sequencing analysis of certain parts of the virus gene was performed.

RESULTS

We identified the first patient who developed symptoms (the index case) and we showed that while both patients and staff members of the institutions were infected, the disease in the psychiatric patients was more severe. We attributed these differences to their mental and underlying health conditions.

CONCLUSIONS

It is important to monitor for adenovirus infection in the community, especially in mental health institutions to allow appropriate medical care.

Development of Novel Adenoviral Vectors to Overcome Challenges Observed With HAdV-5-based Constructs

Recombinant vectors based on human adenovirus serotype 5 (HAdV-5) have been extensively studied in preclinical models and clinical trials over the past two decades. However, the thorough understanding of the HAdV-5 interaction with human subjects has uncovered major concerns about its product applicability. High vector-associated toxicity and widespread preexisting immunity have been shown to significantly impede the effectiveness of HAdV-5–mediated gene transfer. It is therefore that the in-depth knowledge attained working on HAdV-5 is currently being used to develop alternative vectors. Here, we provide a comprehensive overview of data obtained in recent years disqualifying the HAdV-5 vector for systemic gene delivery as well as novel strategies being pursued to overcome the limitations observed with particular emphasis on the ongoing vectorization efforts to obtain vectors based on alternative serotypes.

Re-emergent human adenovirus genome type 7d caused an acute respiratory disease outbreak in Southern China after a twenty-one year absence

Human adenoviruses (HAdVs) are highly contagious pathogens causing acute respiratory disease (ARD), among other illnesses. Of the ARD genotypes, HAdV-7 presents with more severe morbidity and higher mortality than the others. We report the isolation and identification of a genome type HAdV-7d (DG01_2011) from a recent outbreak in Southern China. Genome sequencing, phylogenetic analysis, and restriction endonuclease analysis (REA) comparisons with past pathogens indicate HAdV-7d has re-emerged in Southern China after an absence of twenty-one years. Recombination analysis reveals this genome differs from the 1950s-era prototype and vaccine strains by a lateral gene transfer, substituting the coding region for the L1 52/55 kDa DNA packaging protein from HAdV-16. DG01_2011 descends from both a strain circulating in Southwestern China (2010) and a strain from Shaanxi causing a fatality and outbreak (Northwestern China; 2009). Due to the higher morbidity and mortality rates associated with HAdV-7, the surveillance, identification, and characterization of these strains in population-dense China by REA and/or whole genome sequencing are strongly indicated. With these accurate identifications of specific HAdV types and an epidemiological database of regional HAdV pathogens, along with the HAdV genome stability noted across time and space, the development, availability, and deployment of appropriate vaccines are needed.

Human adenovirus type 8: the major agent of epidemic keratoconjunctivitis (EKC)

Human adenovirus type 8 (HAdV-8) is the most common causative agent of a highly contagious eye disease known as epidemic keratoconjunctivitis (EKC). HAdV-8 strains have been classified into genome types HAdV-8A to 8K and HAdV/D1 to D12 according to restriction endonuclease analysis. This review focuses on the significance of HAdV-8 as an agent of EKC. Molecular analysis of HAdV-8 genome types HAdV-53 and HAdV-54 was performed to reveal potential genetic variation in the hexon and fiber, which might affect the antigenicity and tropism of the virus, respectively. On the basis of the published data, three patterns of HAdV-8 genome type distribution were observed worldwide: (1) genome types restricted to a microenvironment, (2) genome types distributed within a country, and (3) globally dispersed genome types. Simplot and zPicture showed that the HAdV-8 genome types were nearly identical to each other. HAdV-54 is very close to the HAdV-8P, B and E genomes, except in the hexon. In a restriction map, HAdV-8P, B, and E share a very high percentage of restriction sites with each other. Hypervariable regions (HVRs) of the hexon were conserved and were 100% identical among the genome types. The fiber knob of HAdV-8P, A, E, J and HAdV-53 were 100% identical. In phylogeny, HVRs of the hexon and fiber knob of the HAdV-8 genome types segregated into monophyletic clusters. Neutralizing antibodies against one genome type will provide protection against other genome types, and the selection of future vaccine strains would be simple due to the stable HVRs. Molecular analysis of whole genomes, particularly of the capsid proteins of the remaining genome types, would be useful to substantiate our observations.

Acute lower respiratory tract infections by adenovirus in children: histopathologic findings in 18 fatal cases

Adenoviruses (Ads) are the 2nd-most common cause of acute lower respiratory tract infections of viral etiology in immunocompetent children who require hospitalization in Argentina. A new pathogenic genomic variant, Ad7h, has been identified and was associated with severe sequelae and a high mortality rate. A retrospective observational study was conducted in hospitalized children with acute lower respiratory tract infections between March 1988 and May 2005. Nasopharyngeal or tracheal aspirates, bacteriological analysis on blood samples and pleural fluids, and histopathologic studies on autopsies were performed. A total of 415 children were included in the study. Sixty-two patients died in the acute stage of illness (1-8 weeks), and postmortem examination was performed on 18 of them. Mean age was 8.25 months. The male to female ratio was 1.3∶1. The Ad was genome typed in 9% of all children, of whom 29 corresponded to the Ad7h variant. This genome type was diagnosed in 7 of the autopsies performed. Necrotizing bronchitis and bronchiolitis with abundant typical adenoviral inclusion nuclear cells and diffuse alveolar damage were the most important findings. Superimposed bacterial infection occurred in 11 cases, and cytomegalovirus was found in 1. In our population, Ad respiratory infection was found to have a severe course with sequelae or death. No differences were observed between lesions caused by other previously described genome types and those found in cases in which Ad7h was identified.

Adenovirus infections in hospitalized patients in Israel: epidemiology and molecular characterization

Adenoviruses can cause a broad spectrum of clinical diseases, most of which are self-limited. However, adenovirus infection can occasionally result in severe or lethal infection. Fifty-five adenovirus serotypes are known today, and they are classified into 7 subgroups (subgroups A to G). Here we examined 282 samples derived from hospitalized patients in Israel (September 2006 to August 2008) who were diagnosed as suffering from adenovirus infections. We used a recently described PCR amplification method and subsequent sequencing to identify the adenovirus. In addition, we studied the medical charts of 106 hospitalized patients from Sheba Medical Center in Israel. The most prevalent adenovirus serotypes found were serotypes 1 (22.8%), 2 (19.2%), 7 (18%), and 3 (14%). In addition, we identified several serotypes that have not been identified previously in Israel. Overall, serotypes of subgroup B were found to be approximately 4 times more prevalent among immunocompromised children than among generally healthy children (52.6%; P < 0.007). The realization that the virus subtypes are different among healthy and immunocompromised patients may lead to more efficient treatment of adenovirus infections among immunocompromised children in the future.

Postinfectious bronchiolitis obliterans in children: clinical and pulmonary function findings

AIM

Postinfectious bronchiolitis obliterans (PIBO) is an infrequent yet potentially severe disorder following acute lower pulmonary infection (ALRI) in children. In infants and young children PIBO have been strongly associated with Adenovirus (Ad). The purpose of this study was to analyze the clinical features and pulmonary function findings in children with PIBO. Cases caused by Ad were compared with cases in which no viral agent was identified.

METHODS

Fifty-eight children with PIBO were prospectively studied. Clinical data and pulmonary function tests (spirometry and plethysmography) were evaluated. Patients were divided in two groups according to the identification of the causal agent. Group 1 (G1): Adenovirus (+) Group 2: No etiologic agent identified.

RESULTS

Fifty-eight patients (male/female ratio 3.4:1); median age 8 years; mean age at initial injury 11 months; median time of hospitalization at acute stage of disease 60 days. Spirometry: FVC 68 ± 13%, FEV1 40.5 ± 11%, FMMF(25-75%) 16.7 ± 7.5%. Pletysmography: TLC 136 ± 22%, FRC 208 ± 50%, RV 343 ± 102%, RV/TLC 59 ± 10, SGaw 0.05 ± 0.02. When clinical, spirometric and plethysmographic data were compared, no statistically significant difference was found between the two groups.

CONCLUSIONS

PIBO is an extremely crippling lung disease with significant obstructive pattern in PFT. Both analyzed groups shared similar characteristics in the acute phase of the disease and in the severity of the sequelar pulmonary disease.

Lower respiratory infections by adenovirus in children. Clinical features and risk factors for bronchiolitis obliterans and mortality

Adenovirus (Ad) respiratory infections have a profound impact in Argentina. Severe chronic disease and a high mortality rate are observed in children after acute lower respiratory infections (ALRI) by Ad.

METHODS

A retrospective observational study was performed to describe clinical characteristics and to analyze risk factors for bronchiolitis obliterans (BO) and death in 415 children hospitalized with ALRI caused by Ad from March 1988 to May 2005.

RESULTS

Mean age of patients was 10.7 months (+/-9.2) Overall 80% of patients were healthy before ALRI. Forty-nine percent recovered, sequelae were observed in 36% and 15% died. Independent risk factors for BO were: >30 days of hospitalization (odds ratio (OR) 27.2, 95% confidence interval (CI) 14.6-50.9), multifocal pneumonia (OR 26.6, 95% CI 5.3-132) and hypercapnia (OR 5.6, 95% CI 3.5-9). Independent risk factors for death in acute stage of disease were: mechanical assistance (OR 121, 95% CI 18.2-814), multifocal pneumonia (OR 102, 95% CI 9.5-31.1), hypercapnia (OR 42.6, 95% CI 10.2-177.1), coagulation disorders (OR 17, 95% CI 8.25-35), neurological symptoms (OR 12.7, 95% CI 3.5-6.6) and co-infection with measles (OR 9.6, 95% CI 2.1-44.2).

CONCLUSIONS

High incidence of sequelae and mortality in previously healthy children after Ad infection was observed in a population of children from Argentina.

Antigenic and genomic characterization of adenovirus associated to respiratory infections in children living in Northeast Brazil

From January to December 1998, nasopharyngeal aspirates were obtained from 482 children with acute respiratory infections attended in emergence department and wards of a teaching hospital in the city of Salvador, Brazil. The samples were tested for the presence of adenovirus by isolation in tissue culture and indirect immunofluorescence assay. Eleven adenoviruses were detected by both methods in the same clinical samples. Infections by adenovirus were observed during seven months of the year without association with rainy season. Genome analysis was performed on these 11 isolates. Species C was represented by serotypes 1, 2 and 5. Within species B, only serotype 7 (Ad7) was detected. Two genomic variants of Ad1, two variants of Ad2, one of Ad5, and one of Ad7 (7h) were identified. This is the first study of molecular epidemiology of adenovirus associated to acute respiratory infections in children living in Northeast Brazil, and contributes to a better understanding of adenovirus infections in the country.

Molecular characterization of hospital-acquired adenovirus infantile respiratory infection in Chile using species-specific PCR assays

BACKGROUND

Adenovirus serotypes 7, 2 and 1 are the second most common cause of viral acute lower respiratory tract infection (ALRI) requiring hospitalization in Chile. Nosocomial outbreaks have high secondary attack and lethality rates, and call for rapid and specific diagnosis.

OBJECTIVE

We compared the results obtained on ALRI specimens by immunofluorescence (IFA) and virus isolation, plus restriction enzyme digestion (RFLP) typing, with universal, species-specific and 7h-specific PCR typing of adenovirus. A second objective was to determine the type of adenovirus implicated in nosocomial infection and nosocomial cross-infection rates.

METHODS

Infants hospitalized for ALRI in the Roberto del Río Children's Hospital (Santiago, Chile) in 1995-1996 had nasopharyngeal aspirates obtained at admission and tested by IFA and virus isolation. Adenovirus isolates were identified by RFLP. When an index case was identified, samples were collected from contacts for 2 consecutive days and twice weekly thereafter for 2 weeks. Further typing of adenovirus isolates was undertaken with universal, species-specific and 7h-specific PCR performed in 2003 on the stored frozen samples.

RESULTS

Fifteen index cases of adenovirus and their 65 contacts were identified. The nosocomial secondary attack rate using PCR was estimated as 46%. PCR had a higher sensitivity (98.7%) compared to virus isolation (90%) and IFA (50%) and facilitated identification of adenovirus strains more easily and accurately than RFLP (91.6% versus 55.8%). Fifty-three percent of the contacts had severe outcomes. The case fatality rate was 16.6% and was associated with adenovirus 7h.

CONCLUSIONS

Prompt, rapid and sensitive methods to identify adenovirus infection are necessary, especially for hospital-acquired adenovirus infections, because of their ease of spread and high fatality rate.

Assessment of genetic variability among subspecies b1 human adenoviruses for molecular epidemiology studies

Adenoviruses exhibit considerable intraserotypic genetic variability. Restriction enzyme analysis of the adenoviral genome is currently the most widely used procedure for the characterization of adenovirus isolates and has been extensively used for molecular epidemiological studies of subspecies B1 adenovirus infections. Comparison of restriction site maps between viral genomes is qualitatively consistent with DNA sequence homology providing that a sufficient number of sites are known. This technique is simple, sensitive, and can be adapted for screening numerous isolates and is therefore particularly useful for analysis of closely related genomes. Restriction enzyme analysis is still the only molecular approach that, at a reasonable cost, can give a "genome-wide" characterization of an adenovirus strain. Polymerase chain reaction (PCR) amplification followed by sequencing of the generated amplicon is the approach of choice for the detailed analysis of specific regions of the viral genome. Several laboratories have recently adopted PCR amplification of the hexon and/or fiber genes for the determination of adenovirus serotype identity, replacing identification by seroneutralization and hemmaglutination-inhibition. This approach permits rapid and objective type-specific identification of human adenoviruses and is especially useful for the characterization of serologically intermediate strains frequently identified among field strains of subspecies B1 adenoviruses.

PCR analysis of egyptian respiratory adenovirus isolates, including identification of species, serotypes, and coinfections

Eighty-eight adenovirus (Ad) isolates and associated clinical data were collected from walk-in patients with influenza-like illness in Egypt during routine influenza surveillance from 1999 through 2002. Respiratory Ad distributions are geographically variable, and serotype prevalence has not been previously characterized in this region. Serotype identity is clinically relevant because it predicts vaccine efficacy and correlates strongly with both clinical presentation and epidemiological pattern. Species and serotype identities were determined using several well-validated multiplex PCR protocols culled from the literature and supplemented with a few novel primer sets designed to identify rare types. The isolates included common species B1 serotypes (Ad3 and Ad7), common species C serotypes (Ad1, Ad2, and Ad5), the less common species B2 serotype Ad11, and three isolates of the rare species B1 serotype Ad16. Two isolates that appear to be variant Ad16 were also identified. Fifteen coinfections of multiple adenoviral types, primarily AdB/AdC and Ad3/Ad7 dual infections, were detected. The majority of these were verified using redundant PCR tests targeted at multiple genes. PCR is able to resolve coinfections, in contrast to traditional serum neutralization tests. PCR is also comparatively rapid and requires very little equipment. Application of the method allowed an inclusive determination of the serotypes found in the Egyptian respiratory sample set and demonstrated that coinfections are common and may play a previously unrecognized role in adenovirus pathogenesis, evolution, and epidemiology. In particular, coinfections may influence adenoviral evolution, as interserotypic recombination has been identified as a source of emerging strains.

Genomic and bioinformatics analyses of HAdV-4vac and HAdV-7vac, two human adenovirus (HAdV) strains that constituted original prophylaxis against HAdV-related acute respiratory disease, a reemerging epidemic disease

Vaccine strains of human adenovirus serotypes 4 and 7 (HAdV-4vac and HAdV-7vac) have been used successfully to prevent adenovirus-related acute respiratory disease outbreaks. The genomes of these two vaccine strains have been sequenced, annotated, and compared with their prototype equivalents with the goals of understanding their genomes for molecular diagnostics applications, vaccine redevelopment, and HAdV pathoepidemiology. These reference genomes are archived in GenBank as HAdV-4vac (35,994 bp; AY594254) and HAdV-7vac (35,240 bp; AY594256). Bioinformatics and comparative whole-genome analyses with their recently reported and archived prototype genomes reveal six mismatches and four insertions-deletions (indels) between the HAdV-4 prototype and vaccine strains, in contrast to the 611 mismatches and 130 indels between the HAdV-7 prototype and vaccine strains. Annotation reveals that the HAdV-4vac and HAdV-7vac genomes contain 51 and 50 coding units, respectively. Neither vaccine strain appears to be attenuated for virulence based on bioinformatics analyses. There is evidence of genome recombination, as the inverted terminal repeat of HAdV-4vac is initially identical to that of species C whereas the prototype is identical to species B1. These vaccine reference sequences yield unique genome signatures for molecular diagnostics. As a molecular forensics application, these references identify the circulating and problematic 1950s era field strains as the original HAdV-4 prototype and the Greider prototype, from which the vaccines are derived. Thus, they are useful for genomic comparisons to current epidemic and reemerging field strains, as well as leading to an understanding of pathoepidemiology among the human adenoviruses.

Five new genome types of adenovirus type 37 caused epidemic keratoconjunctivitis in Sapporo, Japan, for more than 10 years

Human adenovirus type 37 (HAdV-37) is a major cause of epidemic keratoconjunctivitis and has recently been the largest causative agent of keratoconjunctivitis in Japan. To investigate the genetic characteristics of HAdV-37 strains isolated in Sapporo, we analyzed the genome types and genetic relationships of 51 strains isolated there from 1990 through 2001. By using DNA restriction analysis, eight genome types (HAdV-37/D1, HAdV-37/D3, and HAdV-37/D6 to HAdV-37/D11) were identified, including five new ones. The restriction fragments of these genome types shared more than 95% identity with those of the prototype strain. By DNA sequence analysis, five and three single nucleotide substitutions, respectively, were found in partial sequences of the hexon and fiber genes. The combinations of mutations resulted in four hexon and fiber types (hx1 to hx4 and f1 to f4) and six hexon/fiber pairs (hx1/f1, hx2/f1, hx1/f2, hx1/f3, hx3/f4, and hx4/f4). The six pairs correlated well with certain genome types. In all three epidemics of keratoconjunctivitis to strike Sapporo in the past 12 years, specific genome types and fiber types were usually isolated: in the first epidemic, HAdV-37/D1 (f1) and HAdV-37/D3 (f1); in the second, HAdV-37/D6 (f2) and HAdV-37/D8 (f3); and in the third, HAdV-37/D10 (f4) and HAdV-37/D11 (f4). We conclude that mutations in the adenovirus genome occurred chronologically and that certain mutations were correlated with the epidemics of adenoviral keratoconjunctivitis.

Genomic and bioinformatics analysis of HAdV-7, a human adenovirus of species B1 that causes acute respiratory disease: implications for vector development in human gene therapy

Human adenovirus serotype 7 (HAdV-7) is a reemerging pathogen identified in acute respiratory disease (ARD), particularly in epidemics affecting basic military trainee populations of otherwise healthy young adults. The genome has been sequenced and annotated (GenBank accession no. ). Comparative genomics and bioinformatics analyses of the HAdV-7 genome sequence provide insight into its natural history and phylogenetic relationships. A putative origin of HAdV-7 from a chimpanzee host is observed. This has implications within the current biotechnological interest of using chimpanzee adenoviruses as vectors for human gene therapy and DNA vaccine delivery. Rapid genome sequencing and analyses of this species B1 member provide an example of exploiting accurate low-pass DNA sequencing technology in pathogen characterization and epidemic outbreak surveillance through the identification, validation, and application of unique pathogen genome signatures.

Quantitation of adenovirus genome during acute infection in normal children

BACKGROUND

Adenovirus infection causes a wide range of clinical illness in normal children. New molecular techniques allow quantitation of viral genome to study the natural history of adenovirus infection and viral load in normal children.

METHODS

Clinical samples were collected from 38 previously healthy, febrile children, and viral cultures were performed. Quantitative polymerase chain reaction (PCR) was used to detect adenovirus genome and to determine viral load. Adenovirus isolates were genotyped with a PCR-based assay.

RESULTS

Adenovirus culture was positive in 6 children who were diagnosed with acute adenovirus infection. Throat swabs contained high copy numbers of adenovirus genome (1.6 x 10(6)-6 x 10(7) copies/swab) from 4 of 4 adenovirus culture-positive children. Only 2 of 32 adenovirus culture-negative children had detectable adenovirus genome from throat swabs, but with a lower copy number (8 x 10(2) copies/swab). Adenovirus genome was not detected in blood samples from 5 of 6 adenovirus culture-positive children with uncomplicated upper respiratory tract infection and from all adenovirus culture-negative children. High level viremia (1.8 x 10(8)/ml) was detected in an adenovirus culture-positive 6-month-old infant with fever, pneumonia, conjunctivitis and hepatitis. Subsequent reduction in viral load paralleled her clinical recovery. Adenovirus viruria (1 x 10(9) copies/ml) with normal urinanalysis was detected in another adenovirus culture-positive child. All 6 adenovirus isolates were genotyped as adenovirus type 7h.

CONCLUSION

Viral load assessment in clinical samples determined by quantitative PCR can be useful in the diagnosis of adenovirus infection in immunocompetent, febrile children.

Sequence polymorphism in the E3 7.7K ORF of subspecies B1 human adenoviruses

Sequences corresponding to the 7.7K open-reading frame (ORF) of the E3 region of subspecies B1 adenoviruses (Ads) were compared with prototype strains of Ad3, Ad7, Ad16, Ad21, and Ad50 and field isolates representing a variety of genome restriction types of Ad3 and Ad7 to better assess the extent of genetic variation in this intriguing region of the viral genome encoding a product whose function is still unknown. Alignment of 55 species B1 Ad sequences revealed a marked polymorphism in the 7.7K ORF and allowed the identification of eight distinct sequence profiles (SPs) characterized by (1) deletions that retain or change the reading frame, (2) single-base mutations (SBMs) that change the start codon (ATG to ATT or ATC), and (3) other SBMs. mRNAs of expected size for the observed sequence polymorphisms were identified by RT-PCR from DNAse I-treated total RNA extracts of infected cells. Predicted proteins ranged from 0 to 94 amino acids corresponding to molecular masses of 0-11 K. Together with the hypervariable regions of the hexon gene, the E3 7.7K ORF appears to be another area of the Ad genome in which genetic diversity may be generated by illegitimate recombination.

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.

Genome types of adenovirus type 7 isolated in Hiroshima City

One hundred thirty-two strains of adenovirus type 7 were isolated in Hiroshima City during the period 1995-1999. About 80% of the viruses were isolated from patients with respiratory illness, and about 70% were isolated from children younger than 6 years old. DNA restriction analysis was performed on 58 of the 132 isolates. Two genome types corresponding to adenovirus 7d and adenovirus 7h were recognized using BamHI. By using an additional 10 restriction endonucleases (BclI, BglI, BglII, BstEII, HindIII, HpaI, SmaI, PstI, PvuII, and SacI), the 58 isolates were classified finally into five genome types according to Wadell and coworkers' nomenclature system: adenovirus 7d2 (54 isolates), adenovirus 7d3 (one isolate), adenovirus 7d4 (one isolate), adenovirus 7d5 (one isolate), and adenovirus 7h (one isolate), among which adenovirus 7d3, 7d4, and 7d5 were new genome types. Our results indicate that the predominant genome type of adenovirus 7 that circulated in Hiroshima City during the period May 1995-November 1999 was adenovirus 7d2.

Acute viral bronchiolitis and its sequelae in developing countries

Acute viral bronchiolitis (AVB) is a common disease found throughout the world. Various aspects of it are being studied: its epidemiology, diagnosis, prognosis and treatment. Most of these studies are being conducted in developed countries, with only a few taking place in developing countries. Risk factors such as poor nutrition, an adverse environment and early weaning should be studied where these features are common. Treatment aspects such as cost-effectiveness in low income settings need further study. Use of ribavirin and respiratory syncytial virus (RSV)-immunoglobulin are good examples. Post-bronchiolitic sequelae also need to be studied in low income countries. There is evidence that bronchiolitis obliterans is unusually frequent in some Latin-American countries such as Argentina and Brazil. It will be helpful to undertake combined studies in countries with the same socio-economics, investigating the preventive and management aspects of AVB and its sequelae to reduce the morbidity and mortality.

Adenovirus type 7 associated with severe and fatal acute lower respiratory infections in Argentine children

BACKGROUND

Adenoviruses are the second most prevalent cause of acute lower respiratory infection of viral origin in children under four years of age in Buenos Aires, Argentina. The purpose of this study was to analyze the clinical features and outcome of acute lower respiratory infection associated with different adenovirus genotypes in children.

METHODS

Twenty-four cases of acute lower respiratory infection and adenovirus diagnosis reported in a pediatric unit during a two-year period were retrospectively reviewed. Adenovirus was detected by antigen detection and isolation in HEp-2 cells. Adenovirus DNA from 17 isolates was studied by restriction enzyme analysis with Bam HI and Sma I.

RESULTS

Subgenus b was found in 82.3% of the cases, and subgenus c in 17.7%. Within subgenus b, only genotype 7 was detected, with genomic variant 7h in 85.7% (12/14) and genomic variant 7i in 14.3% (2/14). Mean age was 8.8 +/-; 6 months, and male to female ratio was 3.8: 1. At admission, pneumonia was observed in 71% of the cases and bronchiolitis in 29%. Malnutrition occurred in 37% of the cases; tachypnea in 79%; chest indrawing in 66%; wheezing in 58%; apneas in 16%; and conjunctivitis in 29%. Blood cultures for bacteria and antigen detection of other respiratory viruses were negative. During hospitalization, fatality rate was 16.7% (4 /24). Of the patients who died, three had Ad 7h and one Ad 7i. Thus, fatality rate for adenovirus type 7 reached 28.6% (4/14).

CONCLUSIONS

These results show the predominance of adenovirus 7 and high lethality associated with the genomic variants 7h and 7i in children hospitalized with acute lower respiratory infection.

Detection and typing of respiratory adenoviruses in a single-tube multiplex polymerase chain reaction

A multiplex polymerase chain reaction (PCR) assay that is capable of detecting and typing six serotypes of respiratory adenovirus (Ad) was developed, using multiple sets of type-specific primers. The detection of each different serotype depended on distinguishing different numbers and sizes of amplification products on agarose gels following PCR. The multiplex PCR was tested with 26 clinical Ad isolates and other respiratory viruses including influenza viruses, parainfluenza viruses, and respiratory syncytial viruses as well as respiratory bacterial pathogens such as Chlamydia pneumoniae, Streptococcus pneumoniae, Haemophilus influenzae, and Mycoplasma pneumoniae. The multiplex PCR for the detection and typing of Ads gave an excellent correlation with the results by conventional typing with type-specific antisera. This assay may serve as a rapid means of confirming Ad with simultaneous serotype identification of the isolates. It will also have relevance as an adjunctive tool to conventional serotyping for diagnostic and epidemiological purposes.

Molecular epidemiology of adenovirus type 7 in the United States, 1966-2000

Genetic variation among 166 isolates of human adenovirus 7 (Ad7) obtained from 1966 to 2000 from the United States and Eastern Ontario, Canada, was determined by genome restriction analysis. Most (65%) isolates were identified as Ad7b. Two genome types previously undocumented in North America were also identified: Ad7d2 (28%), which first appeared in 1993 and was later identified throughout the Midwest and Northeast of the United States and in Canada; and Ad7h (2%), which was identified only in the U.S. Southwest in 1998 and 2000. Since 1996, Ad7d2 has been responsible for several civilian outbreaks of Ad7 disease and was the primary cause of a large outbreak of respiratory illness at a military recruit training center. The appearance of Ad7d2 and Ad7h in North America represents recent introduction of these viruses from previously geographically restricted areas and may herald a shift in predominant genome type circulating in the United States.

Molecular and epidemiological analyses of human adenovirus type 7 strains isolated from the 1995 nationwide outbreak in Japan

The adenovirus type 7 (Ad7) isolates from the 1995 nationwide outbreak in Japan were genetically and seroepidemiologically analyzed in comparison with Japanese Ad7 strains isolated before 1995 to determine their genome type and to speculate on their origin and causative factors of the outbreak. Twenty-six Ad7 isolates from the outbreak were identified by restriction enzyme analysis as the Ad7d2 genome type, while 22 Ad7 strains sporadically isolated in Japan before 1995 were identified as Ad7d. Partial nucleotide sequencing of the E3 region of Ad7d2 revealed a nucleotide substitution of G to A at position 265, resulting in the absence of the BstEII site and making Ad7d2 distinct from Ad7d. In Hiroshima City, Japan, no Ad7 was isolated from 1982 to 1994, but 43 and 50 Ad7 strains were isolated in 1995 and 1996, respectively. A seroepidemiological study of 251 serum samples collected in 1989 in Hiroshima City showed that only 2.8% of the samples were positive for Ad7. These results indicate that the 1995 outbreak of Ad7 in Japan was caused by the Ad7d2 genome type, which might have been introduced from outside Japan. The results also suggest that the low mass immunity in Japan was critical for the outbreak and that the mutation in the E3 region in Ad7d2 may have influenced transmission.

Multicentered study of viral acute lower respiratory infections in children from four cities of Argentina, 1993-1994

This study describes the first multicentered study of acute lower respiratory infection viral etiology in young children from four different geographical areas of Argentina. A total of 1,278 children under 5 years of age, hospitalized in primary care centers from Buenos Aires, Córdoba, Santa Fé and Mar del Plata cities during a 2-year period were studied (1993-1994). Nasopharyngeal aspirates were investigated for respiratory syncytial virus (RSV), adenovirus, parainfluenza, and influenza A and B viruses by indirect immunofluorescence. Out of the patients studied, 946 (74%) were under 1 year of age. Viruses were detected in 399 patients (32%). RSV was observed in 25.3% of the samples, representing 78.2% of all viral positive cases. Adenoviruses were detected in 2.5% of the cases, parainfluenza in 2.2%, influenza A in 2.1%, and influenza B in 0.2%. Compared with other viruses, the higher RSV frequency was statistically significant (P < 0.000). Most RSV cases were detected between May and September with a significant peak in July (P < 0.000). Pneumonia was observed in 46% of the patients, bronchiolitis in 41% and other entities in 13%. The case fatality rate observed during the 2 year study was 0.73%. Most of the above respiratory viruses were detected in the four cities, however, the frequency of RSV and influenza were different in the southern city.

Outbreak of adenovirus genome type 7d2 infection in a pediatric chronic-care facility and tertiary-care hospital

An outbreak of adenovirus infection that involved residents of a pediatric chronic-care facility, staff of a tertiary-care hospital, and a nosocomial hospital case was studied. In the pediatric facility, 31 (33%) of 93 residents had adenovirus infection, and 8 died. Risk factors for illness were an age of < 7 years (P = .004), presence of a tracheostomy (P = .015), and residence on a particular floor (P < .001). In the tertiary-care hospital, 36 health care workers had adenovirus infection; 26 (72%) had failed to follow strict contact and droplet precautions, and 30 (83%) continued to care for patients while they had symptoms. A 5-month-old patient with underlying lung disease acquired severe adenovirus infection in this hospital. All isolates were adenovirus type 7 (Ad7). DNA restriction analysis revealed the band patterns of all isolates to be identical and characteristic of the genome type d2. Thus, Ad7d2 caused significant morbidity and mortality in persons in the pediatric chronic-care facility and tertiary-care hospital. This is the first published description of Ad7d2 strains in the United States.

Rapid typing of human adenoviruses by a general PCR combined with restriction endonuclease analysis

We have developed a system for rapid typing of adenoviruses (Ads) based on a combination of PCR and restriction endonuclease (RE) digestion (PCR-RE digestion). Degenerated consensus primers were designed, allowing amplification of DNA from all 51 human Ad prototype strains and altogether 44 different genome variants of Ad serotypes 1, 3, 4, 5, 7, 11, 19, 40, and 41. The 301-bp amplimer of 22 prototype strains representing all six subgenera and the genome variant was selected as a target for sequencing to look for subgenus and genome type variabilities. The sequences obtained were used to facilitate the selection of specific REs for discrimination purposes in a diagnostic assay by following the concept of cleavage or noncleavage of the 301-bp amplimer. On the basis of these results, a flowchart was constructed, allowing identification of subgenus B:2 and D serotypes and almost complete distinction of subgenus A, B:1, C, E, and F serotypes. Application of the PCR-RE digestion system to clinical samples allowed typing of 34 of 40 clinical samples positive for Ad. The genome type determined by this method was identical to that obtained by traditional RE typing of full-length Ad DNA. The remaining six samples were positive only after a nested PCR. Therefore, to reduce the risk of false-negative results, samples scored negative by the PCR-RE digestion system should be evaluated by the described nested PCR. Used in combination, the PCR-RE digestion method and the nested PCR provide a reliable and sensitive system that can easily be applied to all kinds of clinical samples when rapid identification of adenoviruses is needed.

Isolation and identification of adenovirus in hospitalized children, under five years, with acute respiratory disease, in Havana, Cuba

Nine Adenovirus (Ad) strains isolated in Cuba, from 128 nasopharingeal swab specimens of children below five years old, with acute respiratory diseases, during 1996 and 1997, were studied by restriction enzyme analysis of genomic DNA with two endonucleases BamH I and Sma I. All different fragment patterns were compared with the respective prototypes. The identified adenoviruses were Ad 1 (n=4), Ad 2 (n=1) and Ad 6 (n=4). Males were more frequently infected than females. The analysis of the occurrence of these Adenovirus strains of subgenus C revealed that Ad 1 and Ad 6 were the predominant serotypes in 1996 and in 1997, respectively.

Specific subgroup B adenovirus diagnosis by PCR of the fibre gene

OBJECTIVE

A highly sensitive and specific PCR assay targeting regions of the fibre gene was developed for the identification of subgroup B adenovirus strains. This is critical, since these adenovirus strains are frequently associated with severe respiratory infections in infants and new-borns.

METHODS

Clinical samples from nasopharyngeal aspirates were analysed by PCR using several sets of primers corresponding to sequences of the gene coding for the fibre protein.

RESULTS

The assay allowed the detection and identification of all the genotypes of adenovirus subgroup B, based on the size of the amplified product when analysed on polyacrilamide gel electrophoresis. Specifically, one set of primers was able to amplify DNA of subgroup B but not subgroup C and E viruses.

CONCLUSION

The detection of adenovirus and the genotyping can be done on a routine basis by a PCR assay using the fibre gene as a target. The assay allows the identification of ADV subgroup B, including genotype 7h, which is the single most important viral pathogen associated with respiratory diseases in infants and young children in the southern part of South America.

Differential effects of respiratory syncytial virus and adenovirus on mononuclear cell cytokine responses

Respiratory syncytial virus (RSV) and adenovirus (Advs) serotype 3 (Adv3) and 7h (Adv7h) are associated with mild to severe respiratory infection and are indistinguishable during the acute phases of the illnesses. However, outcome and long-term prognosis are different with both infections. RSV infection is associated with later development of asthma, and Adv, mainly Adv7h, with severe lung damage, bronchiectasis, and hyperlucent lung. We hypothesized that this difference could be partly due to different immune responses induced by these viruses. To test this hypothesis we quantified TCD4+, TCD8+, and BCD19+ expressing the interleukin-2 receptor-alpha chain (CD25) and interferon-gamma (IFN-gamma), interleukin (IL)-10, and IL-4 in the supernatant of peripheral blood mononuclear cells (PBMC) from school children infected in vitro with and without RSV, Adv7h, and Adv3 and after phytohemagglutinin (PHA) stimulation in the presence or absence of these viruses at a multiplicity of infection (MOI) of 1. PBMC from every child produced more IL-10 (p </= 0.05) when infected with RSV than with Advs and noninfected control, and Adv induced more (p </= 0.05) IFN-gamma than did RSV and control. The IL-10/IFN-gamma ratio was significantly higher (p </= 0.05) in RSV-infected and significantly lower (p </= 0.05) in Adv-infected PBMC, than in noninfected cells. PHA-stimulated BCD19+ RSV- infected cells expressed more (p </= 0.05) IL-2R than did Adv-infected cells. These results suggest that Advs induce a Th-1-type immune response that is not seen with RSV. These patterns persist despite intersubject variation in the absolute quantity of cytokine produced.

Genomic analysis of adenovirus isolated from Argentinian children with acute lower respiratory infections

BACKGROUND

Adenoviruses are the second cause of acute lower respiratory infection (ALRI) of viral origin in small children from Buenos Aires, Argentina.

OBJECTIVE

The aim of this study was to characterize, by restriction enzyme analysis, 17 adenovirus strains isolated from the nasopharyngeal aspirates of children under 2 years of age hospitalized due to ALRI.

STUDY DESIGN

Seventeen adenovirus strains isolated between May 1991 and December 1992 in one hospital of Buenos Aires were studied. Adenoviruses were amplified in HEp-2 cells and viral DNA was studied with the restriction enzymes Bam HI and Sma I.

RESULTS AND CONCLUSIONS

Eighty two percent (14/17) of the isolates were classified as adenoviruses from subgenus b and 17.7% (3/17) belonged to subgenus c. Genome type 7 h was detected in 85.7% (12/14) and 7 i in 14.3% (2/14) of the strains from subgenus b. The case lethality associated with adenovirus genome type 7 was 28.6% (4/14 cases). Three fatal cases corresponded to Ad 7 h and one to Ad 7i. Ad 7h shows a high prevalence in small children hospitalized with ALRI and is associated with a high fatality rate.

Lung function in infants with chronic pulmonary disease after severe adenoviral illness

OBJECTIVE

To evaluate pulmonary function and bronchodilator responses in young children with chronic pulmonary disease (CPD) after a severe adenoviral lower respiratory tract infection.

METHODS

Pulmonary function tests were performed in 13 patients (mean age, 1.32 +/- 0.8 years) with CPD and were compared with a control group of 13 healthy infants (mean age, 1.16 +/- 0.4 years).

RESULTS

Respiratory rate, peak tidal expiratory flow (PTEF), PTEF/tidal volume, absolute time up to PTEF, time percentage to PTEF, volume percentage for PTEF, and compliance and resistance of the respiratory system were significantly affected in the CPD group. Similarly, maximal flow at functional residual capacity (V'maxFRC) was 56.0 +/- 42 mL/s and 373 +/- 107 mL/s in the CPD and control groups, respectively (P =.001). No within-group differences with baseline values or between-group differences were noted in response to treatment with ipratropium bromide or albuterol.

CONCLUSION

Young children with CPD caused by adenovirus have pulmonary function changes characterized by severe obstruction and diminished lung distensibility not responsive to the administration of inhaled ipratropium bromide or albuterol.

Acute lower respiratory infections due to respiratory syncytial virus and adenovirus among hospitalized children from Argentina

BACKGROUND

Acute lower respiratory infection (ALRI) is one of the main causes of morbidity and mortality in small children.

OBJECTIVE

The aim of this study was to determine the frequency, seasonality and association with clinical entities of respiratory syncytial virus (RSV) and adenoviruses in children with ALRI.

STUDY DESIGN

During 2 consecutive years (1991-1992), 168 children under 2 years of age hospitalized due to ALRI in a public pediatric hospital of Buenos Aires, Argentina, were studied. RSV and adenoviruses were investigated on nasopharyngeal aspirates (NPA) by indirect immunofluorescence (IIF). HEp-2 cells were used for adenovirus isolation.

RESULTS

RSV was detected in 36.3% and adenoviruses in 14.3% of the cases (P < 0.0001). All adenoviruses detected by IIF were also isolated in culture. Out of 61 RSV cases, 57% corresponded to bronchiolitis and 43% to pneumonia. Ninety-two per cent of children with RSV were less than 1 year old and 70% were less than 5 months. The highest number of RSV cases were observed during winter, with a clear peak in July. Seventy-one per cent of adenovirus cases were associated with pneumonia and only 24% with bronchiolitis (P < 0.02), and predominated in children older than 5 months of age (P < 0.0001). Adenoviruses were detected in almost all months of the year with a small peak at the end of winter and beginning of spring. No significant differences in clinical features at admission, breast feeding or malnutrition were observed among children with RSV or adenovirus diagnosis versus those with no viral etiology. The overall fatality rate was 2.4%. In all fatal cases adenovirus was detected in NPA. Thus, fatality rate among patients with adenoviruses reached 16.7%.

CONCLUSIONS

Our findings show the importance of RSV and adenoviruses associated with ALRI in hospitalized children under 2 years of age and the different epidemiological patterns of the two viruses in Buenos Aires, Argentina.

Molecular epidemiology of adenovirus type 7 in Israel: identification of two new genome types, Ad7k and Ad7d2

The molecular epidemiology of Adenovirus type 7 in Israel was investigated. Fifty-seven adenovirus isolates identified as serotypes 7 or 7a which were recovered from patients in Israel between 1968 and 1995 were analyzed by restriction enzymes digestion using BamHI for primary discrimination and identification of genome types and by six additional enzymes: BstEII, HpaI, BglI, BglII, BclI, and XbaI for confirmation and determination of genomic subtypes. Four digestion patterns were identified with BamHI; one of them was new. Using BstEII, two patterns were obtained, one of them new. Digestion with the other five enzymes yielded known patterns. The analysis revealed four different genomic types and subtypes, which circulated in Israel in different years: subtype 7a1; type 7b, a type with a new BamHI pattern which was designated type 7K, and a subtype with a new BstEII pattern which differed from type 7d by one restriction site and was designated type 7d2. Twenty-two isolates from 1968 through 1975 and from 1984 were Ad7a1. Three isolates from 1973-1974 were Ad7b. Five isolates from 1968 through 1973 were Ad7K and 27 isolates from 1992 through 1995 were Ad7d2. This demonstrates the temporal change in the circulating genome types with up to three genome types cocirculating in 1 year (1973). The two new types, Ad7k and Ad7d2 could have evolved in Israel or could have been imported by travellers and immigrants from neighboring or distant countries.

Genomic characterization of adenovirus serotype 7 isolated in Brazil from acute respiratory disease patients during the period from 1980 to 1991

Forty isolates of adenovirus type 7 were analized by restriction enzyme digestion with BamHI, SmaI, EcoRI and HindIII. These isolates were obtained from acute respiratory disease patients during the years 1980 to 1991. Only two genomic types were found: Ad7b and Ad7e, with Ad7b (87.5%) being more frequent than Ad7e (12.5%). The genomic type Ad7e appeared in the years 1980, 1981 and 1983. Ad7b appeared in 1982 and it was the only genomic type found from 1984 to 1991. Both genomic types were responsible for lower (LRTI) and upper (URTI) respiratory tract infection, but the proportion LRTI/URTI is higher for Ad7b (25/6) than for Ad7e (1/4).

Molecular epidemiology of adenovirus types 3 and 7 isolated from children with pneumonia in Beijing

One hundred fifty strains of adenovirus sero-types 3 (Ad3) and 7 (Ad7) were analyzed. The viruses were isolated from patients, the majority of whom had pneumonia, from central and sub-urban Beijing over a 33-year period (1958-1990). Genomic analysis of DNA extracted from 74 strains of Ad3 and 76 strains of Ad7, with four to five restriction endonucleases (REs), revealed the presence of four and eight genome types, respectively: Ad3a2, Ad3a4, Ad3a5, Ad3a6 and Ad7p1, Ad7a1, Ad7a4, Ad7b, Ad7b1, Ad7d, Ad7d1, and Ad7g. Ad7b1 was the most recently identified genome type. The restriction patterns obtained from 19 representatives of Ad7 genome types after cleavage of the DNA with 12 REs are shown. Ad3a2 first appeared in 1962, and predominated from 1983 to 1988. Ad3a4 was the main causative agent of pneumonia in 1982. Ad3a2 and Ad3a4 are closely related and have 97% pairwise comigrating restriction fragments (PCRF). Ad7d predominated over a period of 11 years (1980-1990). It has 98% PCRF with Ad7b. Ten pairs of strains isolated from different specimens of the same patients were all concordant.

Molecular epidemiology of adenovirus acute lower respiratory infections of children in the south cone of South America (1991-1994)

A collection of 165 adenovirus strains isolated from nasopharyngeal aspirates of children hospitalized for acute lower respiratory infection in Argentina, Chile, and Uruguay between 1991 and 1994 was studied by restriction enzyme analysis (work performed in the Department of Virology, University of Umeå). Of the isolates, 71% (n = 117) were identified as members of subgenus B. Of these, 101 (61.2%) corresponded to genome type 7h, four (2.4%) to genome type 3p2, four (2.4%) to genome type 11a, one (0.6%) to genome type 7b, and one (0.6%) to genome type 7c. Two isolates that were neutralized as serotype 3 and four isolates that were neutralized as serotype 7 exhibited novel BamHI cleavage profiles corresponding to three new genome types denominated 3x, 7i, and 7j. Subgenus C members represented 28.5% of all typed isolates. Five different genome types of Ad1, seven genome types of Ad2, and three genome types of Ad5 were identified of, which two, two, and one, respectively, were found to correspond to new DNA variants. Only one isolate (0.6%) corresponded to Ad4 of subgenus E. Ad7h was isolated from 17 of the 18 fatal cases recorded among the patients included in the study.