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

George K, Kajon AE. A Fulminant Case of Adenovirus Genotype C108 Infection in a Pediatric Stem Cell Transplant Recipient with x-Linked Lymphoproliferative Syndrome Type 1

A 3-year-old male with X-linked lymphoproliferative syndrome type 1 underwent an unrelated umbilical cord blood transplant (UUCBT). The week prior to transplant the patient tested positive for adenovirus (HAdV) with a viral load of <190 copies/mL and was started on cidofovir. UUCBT proceeded as scheduled, and the patient engrafted on day +19. The patient's HAdV load in serum continued to rise with resulting hepatic dysfunction, despite ongoing therapy with cidofovir and HAdV specific T-cell infusions. The patient died 6 months after transplantation having never cleared the virus. Next generation whole genome sequencing and sequence data analyses identified an intertypic recombinant HAdV-C P1H2F2 closely related (99.6% similarity) to genotype C108 in the isolates from three blood specimens obtained during the last week of life. Incidentally, the de novo assembly strategy enabled the detection of an adeno-associated virus type 2 (AAV2) genome in the DNA purified from the plasma isolates. Proteotyping analysis revealed minor differences in the predicted amino acid sequences for E1A, E1B 19K, E1B 55K, DNA polymerase, penton base, and fiber. None of the mutations previously described for HAdV-C5 variants resistant to cidofovir were identified. In silico restriction enzyme analysis revealed a distinct Sac I profile for the identified virus, supporting its designation as a C108 variant.

Human AdV-20-42-42, a Promising Novel Adenoviral Vector for Gene Therapy and Vaccine Product Development

Preexisting immune responses toward adenoviral vectors limit the use of a vector based on particular serotypes and its clinical applicability for gene therapy and/or vaccination. Therefore, there is a significant interest in vectorizing novel adenoviral types that have low seroprevalence in the human population. Here, we describe the discovery and vectorization of a chimeric human adenovirus, which we call HAdV-20-42-42. Full-genome sequencing revealed that this virus is closely related to human serotype 42, except for the penton base, which is derived from serotype 20. The HAdV-20-42-42 vector could be propagated stably to high titers on existing E1-complementing packaging cell lines. Receptor-binding studies revealed that the vector utilized both CAR and CD46 as receptors for cell entry. Furthermore, the HAdV-20-42-42 vector was potent in transducing human and murine cardiovascular cells and tissues, irrespective of the presence of blood coagulation factor X. In vivo characterizations demonstrate that when delivered intravenously (i.v.) in mice, HAdV-20-42-42 mainly targeted the lungs, liver, and spleen and triggered robust inflammatory immune responses. Finally, we demonstrate that potent T-cell responses against vector-delivered antigens could be induced upon intramuscular vaccination in mice. In summary, from the data obtained we conclude that HAdV-20-42-42 provides a valuable addition to the portfolio of adenoviral vectors available to develop efficacious products in the fields of gene therapy and vaccination. IMPORTANCE Adenoviral vectors are under investigation for a broad range of therapeutic indications in diverse fields, such as oncology and gene therapy, as well as for vaccination both for human and veterinary use. A wealth of data shows that preexisting immune responses may limit the use of a vector. Particularly in the current climate of global pandemic, there is a need to expand the toolbox with novel adenoviral vectors for vaccine development. Our data demonstrate that we have successfully vectorized a novel adenovirus type candidate with low seroprevalence. The cell transduction data and antigen-specific immune responses induced in vivo demonstrate that this vector is highly promising for the development of gene therapy and vaccine products.

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.

Genotypes and phylogenetic analysis of adenovirus in children with respiratory infection in Buenos Aires, Argentina (2000-2018)

Human adenoviruses (HAdV) are one of the most frequent causes of respiratory infections around the world, causing mild to severe disease. In Argentina, many studies focused on the association of HAdV respiratory infection with severe disease and fatal outcomes leading to the discovery in 1984 of a genomic variant 7h associated with high fatality. Although several molecular studies reported the presence of at least 4 HAdV species (B, C, D and E) in Argentina, few sequences were available in the databases. In this study, sequences from the hexon gene region were obtained from 141 patients as a first approach to assess the genetic diversity of HAdVs circulating in Buenos Aires, Argentina. Phylogenetic analysis of these sequences and others recovered from public databases confirmed the circulation of the four above-mentioned species represented by 11 genotypes, with predominance in species B and C and shifts in their proportion in the studied period (2000 to 2018). The variants detected in Argentina, for most of the genotypes, were similar to those already described in other countries. However, uncommon lineages belonging to genotypes C2, C5 and E4 were detected, which might indicate the circulation of local variants and will deserve further studies of whole-genome sequences.

Human mastadenovirus-B (HAdV-B)-specific E3-CR1β and E3-CR1γ glycoproteins interact with each other and localize at the plasma membrane of non-polarized airway epithelial cells

The E3 region of all simian and human types classified within species Human mastadenovirus B (HAdV-B) encodes two unique highly conserved ORFs of unknown function designated E3-CR1β and E3-CR1γ. We generated a HAdV-3 mutant encoding small epitope tags at the N-termini of both E3-CR1β and E3-CR1γ (HAdV-3 N-tag wt) and a double knock out (HAdV-3 N-tag DKO) mutant virus that does not express either protein. Our studies show that HAdV-3 E3-CR1β and E3-CR1γ are type I transmembrane proteins that are produced predominantly at late times post infection, are glycosylated, co-localize at the plasma membrane of non-polarized epithelial cells, and interact with each other. At their extreme C-termini HAdV-B E3-CR1β and E3-CR1γ possess a conserved di-leucine motif followed by a class II PDZ domain binding motif (PBM). HAdV-3 E3-CR1β and E3-CR1γ are dispensable for virus growth, progeny release, spread, and plaque formation in A549 cells.

•

HAdV-B E3-CR1β and E3-CR1γ are type I transmembrane proteins.

•

HAdV-B E3-CR1β and E3-CR1γ possess a C-terminal class II PDZ binding motif.

•

HAdV-3 E3-CR1β and E3-CR1γ interact and co-localize at the plasma membrane.

•

HAdV-3 E3-CR1β and E3-CR1γ are dispensable for virus progeny release and spread.

Isolation of a novel intertypic recombinant human mastadenovirus B2 from two unrelated bone marrow transplant recipients

Human adenoviruses (HAdV) are well-known opportunistic pathogens of immunocompromised adult and pediatric patients but specific associations between HAdV species or individual HAdV types and disease are poorly understood.

In this study we report the isolation of a novel HAdV-B2 genotype from two unrelated immunocompromised patients, both recipients of a hematopoietic cell transplant. In both patients, the course of HAdV infection is consistent with a scenario of reactivation of a latent virus rather than a primary opportunistic infection.

Archived HAdV PCR-positive plasma, urine, and stool specimens were processed for virus isolation and detailed molecular characterization. Virus isolates were recovered from patient 1 from PCR-positive urine specimens obtained at days 103 and 116 after transplant in association with gross hematuria, and from a stool specimen obtained 138 days after transplant in association with diarrhea. An isolate was recovered from patient 2 from a PCR-positive urine specimen. Hexon and fiber gene amplification and sequencing were carried out for initial molecular typing, identifying the isolates as an intertypic recombinant with a HAdV-11-like hexon gene and a HAdV-77-like fiber gene. Comprehensive restriction fragment length polymorphism (RFLP) analysis was performed on viral DNA purified from urine and stool isolates, and next generation whole genome sequencing was carried out on purified viral genomic DNA. The genomes of the two isolated strains are 99.5% identical and represent the same RFLP genomic variant. The identified virus is a novel HAdV-B2 genotype designated HAdV-78 exhibiting a HAdV-11-like penton base, a HAdV-11-like hexon and a HAdV-77-like fiber (P11H11F77).

•

A novel HAdV-B2 type was isolated from 2 unrelated stem cell transplant recipients.

•

The two isolated strains are 99.5% identical and represent the same genomic variant.

•

The virus is an intertypic recombinant P11H11F77 designated HAdV-78.

•

Genotype HAdV-78 is closely related to HAdV-77 with a 99% sequence similarity.

Adenovirus Type 4 Respiratory Infections among Civilian Adults, Northeastern United States, 2011-20151

Human adenovirus type 4 (HAdV-4) is most commonly isolated in military settings. We conducted detailed molecular characterization on 36 HAdV-4 isolates recovered from civilian adults with acute respiratory disease (ARD) in the northeastern United States during 2011–2015. Specimens came from college students, residents of long-term care facilities or nursing homes, a cancer patient, and young adults without co-morbidities. HAdV-4 genome types 4a1 and 4a2, the variants most frequently detected among US military recruits in basic training before the restoration of vaccination protocols, were isolated in most cases. Two novel a-like variants were recovered from students enrolled at a college in Tompkins County, New York, USA, and a prototype-like variant distinguishable from the vaccine strain was isolated from an 18-year-old woman visiting a physician’s office in Ulster County, New York, USA, with symptoms of influenza-like illness. Our data suggest that HAdV-4 might be an underestimated causative agent of ARD among civilian adults.

A multigene typing system for human adenoviruses reveals a new genotype in a collection of Swedish clinical isolates

Human adenoviruses (HAdVs) are common pathogens that can cause respiratory, gastrointestinal, urogenital, and ocular infections. They are divided into seven species containing 85 genotypes. Straightforward typing systems might help epidemiological investigations. As homologous recombination frequently shapes the evolution of HAdVs, information on a single gene is seldom sufficient to allow accurate and precise typing, and complete genome-based methods are recommended. Even so, complete genome analyses are not always easy to perform for practical reasons, and in such cases a multigene system can provide considerably more information about the strain under investigation than single-gene-based methods. Here we present a rapid, generic, multigene typing system for HAdVs based on three main deterministic regions of these viruses. Three PCR systems were used to amplify the genes encoding the DNA polymerase, the penton base hypervariable Arg-Gly-Asp-containing loop, and the hexon loop 1 (hypervariable region 1-6). Using this system, we typed 281 clinical isolates, detected members of six out of seven HAdV species (Human mastadenovirus A-F), and could also detect not only divergent strains of established types but also a new recombinant strain with a previously unpublished combination of adenovirus genomes. This strain was accepted by the Human Adenovirus Working Group as a novel genotype: HAdV-86. Seven strains that could not be typed with sufficient accuracy were also investigated using a PCR based on part of the fiber gene. By analysis of corresponding sequences of the 86 known HAdV genotypes, we determined that the proposed typing system should be able to distinguish all non-recombinant types, and with additional fiber information, all known HAdV genotypes.

The complete genome sequence of human adenovirus 84, a highly recombinant new Human mastadenovirus D type with a unique fiber gene

A novel human adenovirus was isolated from a pediatric case of acute respiratory disease in Panama City, Panama in 2011. The clinical isolate was initially identified as an intertypic recombinant based on hexon and fiber gene sequencing. Based on the analysis of its complete genome sequence, the novel complex recombinant Human mastadenovirus D (HAdV-D) strain was classified into a new HAdV type: HAdV-84, and it was designated Adenovirus D human/PAN/P309886/2011/84[P43H17F84]. HAdV-D types possess usually an ocular or gastrointestinal tropism, and respiratory association is scarcely reported. The virus has a novel fiber type, most closely related to, but still clearly distant from that of HAdV-36. The predicted fiber is hypothesised to bind sialic acid with lower affinity compared to HAdV-37. Bioinformatic analysis of the complete genomic sequence of HAdV-84 revealed multiple homologous recombination events and provided deeper insight into HAdV evolution.

Adenovirus

Adenoviruses are a highly prevalent infection that can cause a range of clinical syndromes in immunocompromised patients, ranging from localized disease of the respiratory tract, gastrointestinal tract, or urinary tract to disseminated disease. Adenovirus infections may develop in this unique population as the result of primary infection or reactivation of latent virus. Disease can be potentially progressive with high rates of mortality in patients with pneumonia and disseminated disease. Fortunately, cidofovir and its lipid ester, brincidofovir, appear to be effective for the treatment of adenovirus, although neither is specifically approved for this indication. Adenovirus should always be considered when immunocompromised patients present with any clinical syndrome that could be compatible with adenoviral infection. Once disease is suspected, cultures or molecular testing of appropriate specimens should be obtained and blood should be sent for adenovirus polymerase chain reaction (PCR) whenever adenovirus is suspected. Monitoring of quantitative viral loads in blood is helpful in predicting response to therapy with a significant drop (>1 log) associated with a higher probability of clinical response.

Detection and Genetic Characterization of Adenovirus Type 14 Strain in Students with Influenza-Like Illness, New York, USA, 2014-2015

During the 2014-15 influenza season, 13/168 respiratory samples from students with influenza-like illness (ILI) at a college in New York, USA, were positive for human adenovirus (HAdV); 4/13 samples were positive for HAdV-B14p1. During influenza season, HAdV should be included in the differential diagnostic panel used to determine the etiology of ILI.

Severe Infections with Human Adenovirus 7d in 2 Adults in Family, Illinois, USA, 2014

Human adenovirus 7d, a genomic variant with no reported circulation in the United States, was isolated from 2 adults with severe respiratory infections in Illinois. Molecular typing identified a close relationship with strains of the same genome type isolated from cases of respiratory disease in several provinces of China since 2009.

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.

Molecular Epidemiology and Clinical Manifestations of Adenovirus Respiratory Infections in Taiwanese Children

Human adenoviruses (HAdVs) are important causes of respiratory infections in children. They usually cause mild upper respiratory symptoms, but they can also produce severe pneumonia and other complications. The aims of this retrospective study were to better define the molecular epidemiology of respiratory adenoviruses circulating in Taiwanese children during 2002 and 2013, detect reinfections and co-infections, and characterize the clinical features and laboratory findings according to the causative genotypes.We collected a representative sample of 182 isolates of adenoviruses from 175 children during the 12-year study period. The most prevalent species was HAdV-B genotype 3 (HAdV-3) (92/182, 50.5%) followed by HAdV-C (HAdV-2) (38/182, 20.9%). A single outbreak of HAdV-E (6/182, 3.3%) was noted in 2007. The mean age of children with adenovirus infections was 3.7 ± 2.0 years, with a slight predominance of males (53.1%). Children with HAdV-B tended to be older, had more lower respiratory tract infections, gastrointestinal symptoms, and a higher rate of hospitalization than those with HAdV-C (P < 0.05). Adenovirus co-infections were noted in 25/175 (14.3%) of the children. The most frequent co-infections were with species B (HAdV-3) and C (HAdV-2) (14/25, 56.0%). Additional infections were noted in 23/175 (13.1%) of the children. Of these repeated infections, the initial isolates were always genotypes of HAdV-C. The second isolates were genotypes of HAdV-B or HAdV-E. The clinical features of the first HAdV-B infection and the reinfection of HAdV-B followed the HAdV-C were similar.In conclusion, HAdV-B, C, and E were the only adenovirus species that were isolated from children who were sufficiently ill with respiratory infections to require a visit to the hospital. Human adenovirus B (HAdV-3) accounted for half of these species. HAdV-B was more likely than other species to produce severe disease. The high incidence of adenovirus co-infection and reinfections with different HAdV species supports the need for continued surveillance and has major implications for development of vaccines.

Molecular Epidemiology of Adenovirus Type 21 Respiratory Strains Isolated From US Military Trainees (1996-2014)

BACKGROUND

The circulation of human adenovirus type 21 (HAdV21) in the United States has been documented since the 1960s in association with outbreaks of febrile respiratory illness (FRI) in military boot camps and civilian cases of respiratory disease.

METHODS

To describe the molecular epidemiology of HAdV21 respiratory infections across the country, 150 clinical respiratory isolates obtained from continuous surveillance of military recruit FRI, and 23 respiratory isolates recovered from pediatric and adult civilian cases of acute respiratory infection were characterized to compile molecular typing data spanning 37 years (1978-2014).

RESULTS

Restriction enzyme analysis and genomic sequencing identified 2 clusters of closely related genomic variants readily distinguishable from the prototype and designated 21a-like and 21b-like. A-like variants predominated until 1999. A shift to b-like variants was noticeable by 2007 after a 7-year period (2000-2006) of cocirculation of the 2 genome types. US strains are phylogenetically more closely related to European and Asian strains isolated over the last 4 decades than to the Saudi Arabian prototype strain AV-1645 isolated in 1956.

CONCLUSIONS

Knowledge of circulating HAdV21 variants and their epidemic behavior will be of significant value to local and global FRI surveillance efforts.

A Case of Adenovirus Viremia in a Pediatric Liver Transplant Recipient With Neutropenia and Lymphopenia: Who and When Should We Treat?

Human adenovirus (HAdV) is one of the most feared infections among immunocompromised patients. In particular, in liver transplant patients, HAdV has been implicated in acute liver failure with resultant mortality. The development of current molecular techniques and surveillance testing protocols have provided tools for early detection of HAdV infection, prior to or at the early onset of HAdV disease. Although reduction in immune suppression is the mainstay of therapy, many researchers have also advocated for early administration of antiviral therapy. In multiple reports, cidofovir treatment has been associated with declines in HAdV viral loads or clinical improvement in solid organ and bone marrow transplant recipients. However, there have also been case reports that raise questions about the effectiveness of antiviral therapy in controlling systemic HAdV disease. We report a case of a 26-month-old male recipient of a liver transplantation for hepatoblastoma who developed adenoviremia with an associated hepatitis and gastroenteritis. He recovered with reduced immune suppression but without antiviral therapy, thus avoiding potential toxicities associated with cidofovir therapy. This case a contrast to previous reports, and it highlights the ambiguity regarding which patients should receive HAdV-specific antiviral therapy. Additional knowledge regarding specific pediatric host factors and HAdV factors that predict poor outcomes are needed. Such information would allow clinicians to better stratify patients by risk at the time of adenoviremia detection so that low-risk patients are not unnecessarily exposed to medications with potential toxicities.

Identification of a novel intertypic recombinant species D human adenovirus in a pediatric stem cell transplant recipient

BACKGROUND

Human adenoviruses (HAdV) are known opportunistic pathogens in hematopoietic stem cell transplant (SCT) recipients. The detection of HAdV infection in children after SCT has been implicated as a determinant of poor outcome but specific associations between HAdV species or individual HAdV types and disease are poorly understood.

OBJECTIVES

Characterization of a HAdV-D strain isolated from multiple clinical specimens of an 11-year-old female recipient of a matched unrelated donor peripheral SCT for T-cell lymphoma and case report.

STUDY DESIGN

Archived HAdV PCR-positive plasma, urine, and stool specimens were processed for virus isolation and detailed molecular typing. Complete genomic sequencing was carried out on 2 isolates.

RESULTS

The patient tested positive for HAdV DNA by real-time PCR of a stool specimen at 44 days after initiation of a SCT conditioning regimen. In the subsequent 3 months, HAdV was detected in plasma, urine and stool specimens in association with symptoms of gastroenteritis and hemorrhagic cystitis. A novel HAdV-D with a HAdV20-like hexon gene was isolated from both urine and stool specimens. All isolates yielded identical restriction profiles with endonucleases BamHI, BglII, BstEII, HindIII, PstI and SmaI. Analysis of 2 complete genomic sequences further identified the virus as a novel intertypic recombinant HAdV-D (P20/H20/F42) closely related to HAdV42.

CONCLUSIONS

This case highlights the identification of a previously unknown HAdV-D from an immunocompromised host. In this patient, the course of adenovirus infection is compatible with reactivation of a latent virus or a primary opportunistic infection. Adenoviremia in this patient resolved without definitive adenovirus-directed antiviral therapy.

High-incidence of human adenoviral co-infections in taiwan

Background

Respiratory infections caused by adenovirus (HAdV) are common year round. Recently, a significant increase of adenoviral infections was observed in Taiwan.

Objective

To understand the prevalence and molecular epidemiology of respiratory adenovirus circulating in Taiwan for the past decade.

Study Design

One hundred and twenty-six human adenoviruses, isolated between 2002 to 2011, were characterized via DNA sequencing of the hexon and fiber genes. The nucleotide sequences were then compared by phylogenetic analysis.

Results

HAdV-B3 accounted for 64.3% (81/126) and peaked almost every year, whereas the sequences of hexon and fiber genes of HAdV-B3 were highly conserved in different years. A high incidence of co-infection of adenoviruses was observed (19.0%, 24/126); HAdV-B3 co-infected with HAdV-C2 was the most common combination (58.3%, 14/24). An additional interesting finding of repeated infection was noted in 10 children, all of whom showed first infection with adenovirus species HAdV-C, followed by species HAdV-B or HAdV-E.

Conclusions

HAdV-B3 was the predominant type of respiratory adenovirus circulating in Taiwan over the past ten years. This merits further attention for vaccine development. Furthermore, the observed high-incidence of adenoviral co-infections along with repeated infections found in our study provides important epidemiological insights into adenovirus infections.

Deaths associated with human adenovirus-14p1 infections, Europe, 2009-2010

Human adenovirus (HAdV) serotype 14 is rarely identified. However, an emerging variant, termed HAdV-14p1, recently has been described in the United States in association with outbreaks of acute respiratory disease with high rates of illness and death. We retrospectively analyzed specimens confirmed positive for HAdV by immunofluorescence, virus culture, or real-time PCR during July 1, 2009-July 31, 2010, and describe 9 cases of HAdV-14p1 infection with characteristic mutations in the fiber and E1A genes that are phylogenetically indistinguishable from the viruses previously detected in the United States. Three patients died; 2 were immunocompromised, and 1 was an immunocompetent adult. We propose that surveillance should be increased for HAdV-14p1 and recommend that this virus be considered in the differential diagnosis of sudden-onset acute respiratory disease, particularly fatal infections, for which an etiology is not clear.

A naturally occurring human adenovirus type 7 variant with a 1743 bp deletion in the E3 cassette

Human adenovirus type 7 (HAdV-7) is an important cause of acute respiratory disease (ARD). Different genomic variants of HAdV-7 have been described, designated 7a-7l. In a previous study to investigate risk factors for ARD and wheezing, nasopharyngeal samples were collected from 90 ill children seeking medical attention in Ribeirão Preto, São Paulo, Brazil. HAdVs were identified in 31 samples and were characterized by serum neutralization and genome restriction analysis. Eleven HAdVs were identified as being HAdV-7, five of which were classified as being of genome type 7p (Gomen). Six other HAdV-7 isolates gave new restriction profiles with all enzymes used and were classified as being a new genomic variant, 7m. These isolates were further characterized by sequencing. The hexon and fiber genes of the 7m variant were nearly identical to the prototype, 7p. However, nucleotide sequences from the E3 cassette revealed a 1743 bp deletion affecting the 16.1K, 19K, 20.1K and 20.5K ORFs.

Fatal disseminated adenovirus infection in a young adult with systemic lupus erythematosus

BACKGROUND

The use of corticosteroids and other immunosuppressive agents increases the risk of infection in patients with systemic lupus erythematosus (SLE). The role of human adenoviruses (HAdV) in the etiology of acute viral diseases in these patients is not known.

OBJECTIVES

Describe a case of acute fatal disseminated adenovirus infection in an SLE patient receiving immunosuppressive therapy.

STUDY DESIGN

Case report and detailed viral diagnosis by real time PCR and molecular typing of virus isolates by sequencing of hexon and fiber genes and restriction enzyme analysis of viral DNA.

RESULTS

HAdV was detected by real time PCR in multiple clinical specimens including respiratory, urine, plasma, synovial fluid, and cerebrospinal fluid. Amplification and sequence analysis of the hexon and fiber genes identified the virus as HAdV-7-like for both coding regions. Adenoviruses isolated from respiratory and urine specimens were identical and corresponded to genome type 7d2 by restriction enzyme analysis of viral DNA. The isolated strain encodes a unique fiber gene with a 6-nucleotide deletion corresponding to amino acid positions 250 and 251 in the knob region and not previously described for closely related genomic variants of HAdV-7.

CONCLUSIONS

Adenovirus detection should be included in the diagnostic testing to determine the infectious etiology of fever and/or respiratory symptoms in SLE patients.

Computational analysis of human adenovirus serotype 18

The genome of the sole remaining unsequenced member of species A, human adenovirus type 18 (HAdV-A18), has been sequenced and analyzed. Members of species A are implicated as gastrointestinal pathogens and were shown to be tumorigenic in rodents. These whole genome and in silico proteome data are important as references for reexamining and integrating earlier work and observations based on lower resolution techniques, such as restriction enzyme digestion patterns, particularly for hypotheses based on pre-genomics data. Additionally, the genome of HAdV-A18 will also serve as reference for current studies examining the molecular evolution and origins of human and simian adenoviruses, particularly genome recombination studies. Applications of this virus as a potential vector for gene delivery protocols may be practical as data accumulate on this and other adenovirus genomes.

Open reading frame E3-10.9K of subspecies B1 human adenoviruses encodes a family of late orthologous proteins that vary in their predicted structural features and subcellular localization

Subspecies B1 human adenoviruses (HAdV-B1s) are important causative agents of acute respiratory disease, but the molecular bases of their distinct pathobiology are still poorly understood. Marked differences in genetic content between HAdV-B1s and the well-characterized HAdV-Cs that may contribute to distinct pathogenic properties map to the E3 region. Between the highly conserved E3-19K and E3-10.4K/RIDα open reading frames (ORFs), and in the same location as the HAdV-C ADP/E3-11.6K ORF, HAdV-B1s carry ORFs E3-20.1K and E3-20.5K and a polymorphic third ORF, designated E3-10.9K, that varies in the size of its predicted product among HAdV-B1 serotypes and genomic variants. As an initial effort to define the function of the E3-10.9K ORF, we carried out a biochemical characterization of E3-10.9K-encoded orthologous proteins and investigated their expression in infected cells. Sequence-based predictions suggested that E3-10.9K orthologs with a hydrophobic domain are integral membrane proteins. Ectopically expressed, C-terminally tagged (with enhanced green fluorescent protein [EGFP]) E3-10.9K and E3-9K localized primarily to the plasma membrane, while E3-7.7K localized primarily to a juxtanuclear compartment that could not be identified. EGFP fusion proteins with a hydrophobic domain were N and O glycosylated. EGFP-tagged E3-4.8K, which lacked the hydrophobic domain, displayed diffuse cellular localization similar to that of the EGFP control. E3-10.9K transcripts from the major late promoter were detected at late time points postinfection. A C-terminally hemagglutinin-tagged version of E3-9K was detected by immunoprecipitation at late times postinfection in the membrane fraction of mutant virus-infected cells. These data suggest a role for ORF E3-10.9K-encoded proteins at late stages of HAdV-B1 replication, with potentially important functional implications for the documented ORF polymorphism.

Outbreak of febrile respiratory illness associated with adenovirus 11a infection in a Singapore military training cAMP

Outbreak cases of acute respiratory disease (ARD) associated with subspecies B2 human adenovirus 11a (HAdV-11a) infection were detected during 2005 in a military basic training camp in Singapore. The Singapore HAdV-11a strain is highly similar to other Asian strains of HAdV-11, including strain QS-DLL, which is responsible for the recently described 2006 outbreak of ARD in China.

Molecular characterization of an adenovirus 3-16 intertypic recombinant isolated in Argentina from an infant hospitalized with acute respiratory infection

An intertypic recombinant adenovirus with a serotype 3-like hexon gene and a serotype 16-like fiber (99% identical to that of the prototype strain of human adenovirus 16 [HAdV-16], Ch79) was isolated in Argentina from an infant admitted to the hospital with acute respiratory disease. Consistent with the results of molecular characterization, strain Arg827/04 was designated H3-F16.

Genomic characterization of human adenovirus 36, a putative obesity agent

Increased levels of serum antibody titers against human adenovirus 36 (HAdV-D36) are associated with human obesity and experimental obesity in laboratory animals. While HAdV-D36 has been studied as an infectious agent implicated in obesity for over a decade, the complete genome sequence and its analysis have yet to be reported. A detailed analysis of the genome sequence of HAdV-D36 may be important to understand its role in obesity. Genomic and bioinformatic comparisons with other HAdVs identified differences that suggested unique functions. Global pairwise genome alignment with all sequenced human adenovirus D (HAdV-D) genomes revealed areas of nonconserved sequences in the hexon, E3 CR1 beta, E3 CR1 gamma, and fiber genes. Phylogenetic analysis of all HAdV-D36 proteins confirmed that this virus belongs to species Human adenovirus D. This genomic analysis of HAdV-D36 provides an important tool for comprehending the role that this unique adenovirus may play in human obesity. Low amino acid sequence identity in the E3 CR1 beta and CR1 gamma genes may suggest distinctive roles for these proteins. Furthermore, the predicted molecular models of the HAdV-D36 fiber protein seem to implicate a unique tissue tropism for HAdV-D36.