Serotyping of adenoviruses on conjunctival scrapings by PCR and sequence analysis

Remarkable increase in the detection and molecular characterization of adenovirus F41 in children with acute gastroenteritis in Japan, 2017-2023

Human adenovirus (HAdV) is one of the causative viruses of acute gastroenteritis (AGE) in children worldwide. Species F is known to be enteric adenovirus (genotypes 40 and 41) detected in stool samples. In Japan, we conducted an epidemiological study and molecular characterization of HAdV before and after the COVID-19 pandemic from 2017 to 2023. Among 821 patients, HAdV was detected in 118 AGE cases (14.4%). During a period of 6 years, the HAdV detection rates for each year were relatively low at 3.7% and 0%, in 2017-2018, and 2020-2021, respectively. However, the detection rate increased to remarkably high rates, ranging from 13.3% to 27.3% in the other 4-year periods. Of these HAdV-positive strains, 83.1% were F41 genotypes and 16.9% were other genotypes (A31, B3, C1, C2/C6, and C5). Phylogenetic analyses of the nucleotide and deduced amino acid sequences of the full-length hexon gene demonstrated that HAdV-F41 strains were comprised of three clades, and each clade was distributed across the study period from 2017 to 2023. Analysis of deduced amino acid sequences of the hexon gene of the representative HAdV-F41 strains from each clade revealed numerous amino acid substitutions across hypervariable regions (HVRs) from HVR-1 to HVR-7, two insertions in HVR-1 and HVR-7, and two deletions in HVR-1 and HVR-2 of the hexon gene compared to those of the prototype strain, particularly, those of clade 3 HAdV-F41 strains. The findings suggested that the HAdV-F41 of each clade was stable, conserved, and co-circulated for over two decades in Japan.

Molecular Typing and Rapid Identification of Human Adenoviruses Associated With Respiratory Diseases Using Universal PCR and Sequencing Primers for the Three Major Capsid Genes: Penton Base, Hexon, and Fiber

Human adenoviruses (HAdVs) within species B, C, and E are responsible for highly contagious and potentially severe respiratory disease infections. The traditional method to type these pathogens was based on virus neutralization and hemagglutination assays, which are both time-consuming and difficult, particularly due to the nonavailability of reagents. Subsequent molecular typing based on the partial characterization of the hexon gene and/or the restriction enzyme analysis (REA) of the genomes is inadequate, particularly in identifying recombinants. Here, a rapid, simple, and cost-effective method for molecular typing HAdV respiratory pathogens is presented. This incorporates three pairs of universal PCR primers that target the variable regions of the three major capsid genes, i.e., hexon, penton base, and fiber genes, that span the genome. The protocol enables typing and characterization of genotypes within species B, C, and E, as well as of some genotypes within species D and F. To validate this method, we surveyed 100 children with HAdV-associated acute respiratory infections identified by direct immunofluorescence (Hong Kong; July through October, 2014). Throat swab specimens were collected and analyzed by PCR amplification and sequencing; these sequences were characterized by BLAST. HAdVs were detected in 98 out of 100 (98%) samples, distributing as follows: 74 HAdV-B3 (74%); 10 HAdV-E4 (10%); 7 HAdV-C2 (7%); 2 HAdV-C6 (2%); 1 HAdV-B7 (1%); 1 HAdV-C1 (1%); 2 co-infection (2%); and 1 novel recombinant (1%). This study is the first detailed molecular epidemiological survey of HAdVs in Hong Kong. The developed method allows for the rapid identification of HAdV respiratory pathogens, including recombinants, and bypasses the need for whole genome sequencing for real-time surveillance of circulating adenovirus strains in outbreaks and populations by clinical virologists, public health officials, and epidemiologists.

Genetic characterization and phylogenetic variations of human adenovirus-F strains circulating in eastern India during 2017-2020

Human adenovirus-F (HAdV-F) (genotype 40/41) is the second-most leading cause of pediatric gastroenteritis after rotavirus, worldwide, accounting for 2.8%-11.8% of infantile diarrheal cases. Earlier studies across eastern India revealed a shift in the predominance of genotypes from HAdV41 in 2007-09 to HAdV40 in 2013-14. Thus, the surveillance for HAdV-F genotypes in this geographical setting was undertaken over 2017-2020 to analyze the viral evolutionary dynamics. A total of 3882 stool samples collected from children (≤5 years) were screened for HAdV-F positivity by conventional PCR. The hypervariable regions of the hexon and the partial shaft region of long fiber genes were amplified, sequenced, and phylogenetically analyzed with respect to the prototype strains. A marginal decrease in enteric HAdV prevalence was observed (9.04%, n = 351/3882) compared to the previous report (11.8%) in this endemic setting. Children <2 years were found most vulnerable to enteric HAdV infection. Reduction in adenovirus-rotavirus co-infection was evident compared to the sole adenovirus infection. HAdV-F genotypes 40 and 41 were found to co-circulate, but HAdV41 was predominant. HAdV40 strains were genetically conserved, whereas HAdV41 strains accumulated new mutations. On the basis of a different set of mutations in their genome, HAdV41 strains segregated into 2 genome type clusters (GTCs). Circulating HAdV41 strains clustered with GTC1 of the fiber gene, for the first time during this study period. This study will provide much-needed baseline data on the emergence and circulation of HAdV40/41 strains for future vaccine development.

Efficacy of compartmentalization in controlling an adenovirus type 54 keratoconjunctivitis outbreak on Oki Island, Japan

PURPOSE

To analyze the epidemiologic characteristics of an outbreak of human adenovirus type 54 (HAdV-54) on Oki Island, Shimane Prefecture, Japan, in 2017 and to assess the effectiveness of a compartmentalization method in controlling the incidence and spread.

STUDY DESIGN

Retrospective cohort study.

METHODS

The infection was diagnosed in 136 individuals, and typing was confirmed by PCR and direct sequencing. The epidemiologic characteristics of the disease including the infection rate, incubation period, and basic reproductive number (R0), ie, number of cases directly infected by an infectious patient during the course of the disease, were investigated. The effectiveness of compartmentalization for infection control was determined by simulating the outbreak using the Susceptible-Exposed-Infectious-Recovered (SEIR) model.

RESULTS

The majority of the HAdV-54-infected individuals were the children of 3 nursery schools (A, B, and C) and their parents on Oki Island. The infection rates in the 3 schools were 13.2%, 16.9%, and 17.2%, respectively. The one class of school B without the index case was initially compartmentalized, and the infection rate in this compartment was 0%. The incubation period was calculated to be 9.3 ± 3.5 days, and the disease duration, 13.0 ± 5.4 days. The R0 was 1.43. Using these parameters, a SEIR model was constructed. The SEIR model well predicted the daily incidence of infection and indicated that the compartmentalization method provides effective reduction in the incidence of the infection, with much earlier control.

CONCLUSIONS

The compartmentalization method is effective to control HAdV-54 outbreaks.

Quantitative investigation of viral load in acute to subacute human adenovirus type 54 conjunctivitis

To understand the clinical course of human adenoviral (HAdV) conjunctivitis for establishing a better treatment regimen, thirty-eight eyes of 19 patients with HAdV-54 conjunctivitis for less than one week from onset were evaluated for clinical signs and symptoms and DNA copy numbers. It is observed that a viral load of 10⁴-10⁵ is required to develop symptoms of HAdV conjunctivitis, as symptoms were present in all the eyes whose viral load was ≥10⁴ at least once during the course. Next, it is observed that asymptomatic infections in contralateral eyes are common as the virus was detected in most eyes that did not develop conjunctivitis. Furthermore, there was no rapid decrease of the viral load in healed eyes, on the contrary, the viral load in healed eyes on day 15 was significantly higher than in unhealed eyes. This was likely due to corticosteroid instillation that rapidly alleviated symptoms but prolonged the duration of viral shedding. Recently, combination treatment with iodine and corticosteroids has been recommended for HAdV conjunctivitis. Assessing changes in viral load as well as clinical symptoms would be helpful to better understand the clinical course of this disease.

Increased risk of rhinovirus infection in children during the coronavirus disease-19 pandemic

Background

Coronavirus disease (COVID‐19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), was first detected in Japan in January 2020 and has spread throughout the country. Previous studies have reported that viral interference among influenza virus, rhinovirus, and other respiratory viruses can affect viral infections at the host and population level.

Methods

To investigate the impact of COVID‐19 on influenza and other respiratory virus infections, we analyzed clinical specimens collected from 2244 patients in Japan with respiratory diseases between January 2018 and September 2020.

Results

The frequency of influenza and other respiratory viruses (coxsackievirus A and B; echovirus; enterovirus; human coronavirus 229E, HKU1, NL63, and OC43; human metapneumovirus; human parainfluenza virus 1, 2, 3, and 4; human parechovirus; human respiratory syncytial virus; human adenovirus; human bocavirus; human parvovirus B19; herpes simplex virus type 1; and varicella‐zoster virus) was appreciably reduced among all patients during the COVID‐19 pandemic except for that of rhinovirus in children younger than 10 years, which was appreciably increased. COVID‐19 has not spread among this age group, suggesting an increased risk of rhinovirus infection in children.

Conclusions

Rhinovirus infections should be continuously monitored to understand their increased risk during the COVID‐19 pandemic and viral interference with SARS‐CoV‐2.

Multiplex and on-site PCR detection of swine diseases based on the microfluidic chip system

BACKGROUND

At present, the process of inspection and quarantine starts with sampling at the customs port, continues with transporting the samples to the central laboratory for inspection experiments, and ends with the inspected results being fed back to the port. This process had the risks of degradation of biological samples and generation of pathogenic microorganisms and did not meet the rapid on-site detection demand because it took a rather long time. Therefore, it is urgently needed to develop a rapid and high-throughput detection assay of pathogenic microorganisms at the customs port. The aim of this study was to develop a microfluidic chip to rapidly detect swine pathogenic microorganisms with high-throughput and higher accuracy. Moreover, this chip will decrease the risk of spreading infection during transportation.

RESULTS

A series of experiments were performed to establish a microfluidic chip. The resulting data showed that the positive nucleic acid of four swine viruses were detected by using a portable and rapid microfluidic PCR system, which could achieve a on-site real-time quantitative PCR detection. Furthermore, the detection results of eight clinical samples were obtained within an hour. The lowest concentration that amplified of this microfluidic PCR detection system was as low as 1 copies/μL. The results showed that the high specificity of this chip system in disease detection played an important role in customs inspection and quarantine during customs clearance.

CONCLUSION

The microfluidic PCR detection system established in this study could meet the requirement for rapid detection of samples at the customs port. This chip could avoid the risky process of transporting the samples from the sampling site to the testing lab, and drastically reduce the inspection cycle. Moreover, it would enable parallel inspections on one chip, which greatly raised the efficiency of inspection.

Molecular typing of conjunctivitis-causing adenoviruses in Hanoi, Vietnam from 2017 to 2019 and complete genome analysis of the most prevalent type (HAdV-8)

Adenoviral conjunctivitis is a common epidemic worldwide. In Vietnam, up to 80,000 patients are infected with adenoviral conjunctivitis annually. However, there are few investigations on the pathogenic adenoviruses that cause conjunctivitis. In total, 120 eye-swab samples were collected from patients with viral conjunctivitis symptoms in Hanoi, Vietnam from 2017 to 2019. Human adenoviruse (HAdV) was detected in 67 samples (55.83%) using polymerase chain reaction amplification of at least one of three HAdV-specific marker genes (hexon, penton, and fiber). Of the 67 HAdV samples, 46 samples could be analyzed by all three marker genes. DNA sequence analysis and phylogenetic tree building based on the three marker genes from the 46 HAdV samples revealed five different HAdV types associated with conjunctivitis in Hanoi, including HAdV-3 (4.3%), HAdV-4 (2.2%), HAdV-8 (89.1%), HAdV-37 (2.2%), and a potential recombinant type between types HAdV-8 and HAdV-3 (2.2%). This showed that HAdV-8 was the most common type identified in Hanoi. Complete genome analysis of HAdV-8 isolated from a Vietnamese patient (VN2017) using Sanger sequencing revealed 34 unique nucleotide changes, indicating that the adenovirus continuously accumulates new mutations. Hence, continuous surveillance of HAdV-8 changes in Vietnam is necessary in the future.

Comparative study of topical regimen for adenoviral kearoconjunctivitis by 0.1% fluorometholone with and without polyvinyl alcohol iodine

PURPOSE

The aim of this study was to compare the efficacy of the topical regimens of iodine/steroids vs. antibiotics/steroids in acute to subacute adenoviral keratoconjunctivitis.

STUDY DESIGN

A prospective open-label study.

PATIENTS AND METHODS

Nineteen patients diagnosed with unilateral or bilateral adenoviral conjunctivitis at less than 1 week from onset were enrolled in this study. Patients were divided randomly into two groups; group 1 was treated with 1.5% levofloxacin with 0.1% fluorometholone administered four times a day and group 2 was treated with a sixfold dilution of polyvinyl alcohol iodine (PAI) solution with 0.1% fluorometholone four times a day. Conjunctival samples from all affected eyes were obtained for real-time PCR. The total scores of acute signs (i.e., eyelid edema, conjunctival injecton, conjunctival discharge, follicules, pseudomembranes, subconjunctival hemorrhage) and symptoms, HAdV DNA copy number, and the presence of multiple subepithelial corneal infiltrates (MSI) were evaluated every 5 visits up to Day 30 after diagnosis.

RESULTS

Comparing the total scores of acute signs and symptoms and viral load, we observed no significant differences between the two groups. At day 15 after diagnosis the proportion of patients with MSI in group 2 (35.7%) was significantly lower than in group 1 (0%).

CONCLUSIONS

The impact of topical iodine/steroid therapy on acute signs and symptoms associated with adenoviral conjunctivitis is limited and not substantially different in the responses to antibiotics/steroids. However, this regimen results in a significant decrease in the incidence of MSI during the subacute phase of infection.

Identification of novel B cell epitopes in the fiber protein of serotype 8 Fowl adenovirus

In recent years, hepatitis-hydropericardium syndrome (HHS) and inclusion body hepatitis (IBH) caused by fowl adenovirus (FAdV) infection have resulted in significant economic losses to the poultry industry worldwide. Epidemiological analysis revealed that serotype FAdV-8 is one of the major pathogenic FAdVs currently prevalent in domestic flocks. Although the fiber protein of FAdV plays vital roles in viral infection and pathogenesis, the B cell epitope in the fiber protein is less known. In this study, two monoclonal antibodies (mAbs) specific to fiber protein of FAdV-8, designated as 4D9 and 5F10, were prepared. Although the mAb 4D9 and 5F10 could not neutralize FAdV-8 infection, 4D9 and 5F10 showed good activities of indirect immunofluorescence, western blot and immunoprecipitation. Epitope analysis revealed that mAb 5F10 recognized 187-219aa in the fiber whereas mAb 4D9 recognized 113-149aa in the fiber. Sequence analysis showed that the epitope recognized by mAb 5F10 was conserve across serotypes FAdV-7, 8a and 8b whereas that for mAb 4D9 was only conserve in FAdV-8b. The generation of mAbs specific to fiber of FAdV-8 and the identification of the novel B cell epitopes here lay the foundation for further studying the antigenicity of the fiber and developing specific diagnosis for FAdV-8.

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.

Worldwide increased prevalence of human adenovirus type 3 (HAdV-3) respiratory infections is well correlated with heterogeneous hypervariable regions (HVRs) of hexon

Human adenovirus type 3 (HAdV-3) respiratory infections occurs worldwide in both children and adults, leading to severe morbidity and mortality, particularly in the paediatric age group and especially in neonates. During HAdV infection, neutralizing antibodies are formed against the epitopes located in the hyper variable regions (HVRs) of the hexon protein. These neutralizing antibodies provide protection against reinfection by viruses of the same type. Therefore it is reasonable to speculate that variations of HAdV-3 in the HVRs could impair the immunity acquired by previous infection with a different strain with variation in its HVRs. HAdV-3 has recently become the major agent of acute respiratory infection worldwide, being responsible for 15% to 87% of all adenoviral respiratory infections. However, despite the increased prevalence of HAdV-3 as respiratory pathogen, the diversity of hexon proteins in circulating strains remains unexplored. This study was designed to explore the variation in HVRs of hexon among globally distributed strains of HAdV-3 as well as to discover possible relationship among them, thus possibly shedding light on the cause for the increased prevalence of HAdV-3. In this study, for the first time we analysed the hexon proteins of all 248 available strains of HAdV-3 from the NCBI database and compared them with those of the HAdV-3 prototype (GB stain). We found that the HVRs of HAdV-3 strains circulating worldwide were highly heterogeneous and have been mutating continuously since -their original isolation. Based on their immense heterogeneity, the strains can be categorized into 25 hexon variants (3Hv-1 to 3Hv-25), 4 of which (3Hv-1 to 3Hv-4) comprises 80% of the strains. This heterogeneity may explain why HAdV-3 has become the most prevalent HAdVs type worldwide. The heterogeneity of hexon proteins also shows that the development of a vaccine against HAdV-3 might be challenging. The data on hexon variants provided here may be useful for the future epidemiological study of HAdV-3 infection.

Small-size recombinant adenoviral hexon protein fragments for the production of virus-type specific antibodies

Background

Adenoviruses are common pathogens infecting animals and humans. They are classified based on serology, or genome sequence information. These methods have limitations due to lengthy procedures or lack of infectivity data. Adenoviruses are easy to produce and amenable to genetic and biochemical modifications, which makes them a powerful tool for biological studies, and clinical gene-delivery and vaccine applications. Antibodies directed against adenoviral proteins are important diagnostic tools for virus identification in vivo and in vitro, and are used to elucidate infection mechanisms, often in combination with genomic sequencing and type specific information from hyper-variable regions of structural proteins.

Results

Here we describe a novel and readily useable method for cloning, expressing and purifying small fragments of hyper-variable regions 1-6 of the adenoviral hexon protein. We used these polypeptides as antigens for generating polyclonal rabbit antibodies against human adenovirus 3 (HAdV-B3), mouse adenovirus 1 (MAdV-1) and MAdV-2 hexon. In Western immunoblots with lysates from cells infected from thirteen human and three mouse viruses, these antibodies bound to homologous full-length hexon protein and revealed variable levels of cross-reactivity to heterologous hexons. Results from immuno-fluorescence and electron microscopy studies indicated that HAdV-B3 and MAdV-2 hexon antibodies recognized native forms of hexon.

Conclusions

The procedure described here can in principle be applied to any adenovirus for which genome sequence information is available. It provides a basis for generating novel type-specific tools in diagnostics and research, and extends beyond the commonly used anti-viral antibodies raised against purified viruses or subviral components.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-017-0822-5) contains supplementary material, which is available to authorized users.

Construction of new primer sets for corresponding to genetic evolution of human adenoviruses in major capsid genes through frequent recombination

A number of novel recombinant human adenoviruses (HAdVs) have recently been identified through sequencing of the complete genomes. The recombinant HAdV sequences share similarity with other types in the major capsid genes, namely the hexon, penton base, and fiber genes, implying recombination events, which may result in escape from the immune response and the acquisition of different organotropisms. Therefore, a surveillance system of HAdVs that considers the effect of frequent recombination on genetic evolution in these genes must be constructed. In this study, we designed new primer sets that can amplify the partial penton base and fiber genes from species HAdV-A to HAdV-F and proteotype HAdVs on the basis of sequence analyses, including previously reported primers that amplify loop 1 of the hexon. Phylogenetic analysis through sequencing with these primers correctly classified clinical HAdV isolates in loop 1 of the hexon gene, the Arg-Gly-Asp (RGD) loop of the penton base gene, and the knob of the fiber gene, which contain neutralizing, hemagglutination, and receptor binding epitopes associated with immunogenicity and tissue tropisms of HAdVs. This study contributes to the accumulation of correct information regarding genetic diversity and evolution in the worldwide HAdV surveillance.

Tracking novel adenovirus in environmental and human clinical samples: no evidence of endemic human adenovirus type 58 circulation in Córdoba city, Argentina

In recent years, several types of human adenovirus (HAdV) have arisen from the recombination between two or more previously known HAdV types, but their epidemiology is poorly understood. In this study, we investigated the circulation of HAdV-58, a recently described HAdV isolated from an HIV-positive patient in Córdoba city, Argentina. For this purpose, a 30-month survey was conducted to study the presence of this type of adenovirus in sewage samples collected at the inlet from a wastewater treatment plant in Córdoba city, Argentina. Complementarily, the virus was sought in stools of HIV-positive patients. Although HAdVs were detected in human stool samples and in a high percentage of sewage samples, no evidence of HAdV-58 circulation was detected. We suggest that there is no endemic circulation of HAdV-58 in the geographical local area. The trend is that the number of identified HAdVs increases over time. In this context, understanding the current circulating HAdVs may be biologically relevant.

Trimeric knob protein specifically distinguishes neutralizing antibodies to different human adenovirus species: potential application for adenovirus seroepidemiology

Adenoviruses (Ads) are non-enveloped DNA viruses that have been extensively studied and used as vectors for gene therapy and several potential vaccines. There are 57 Ad serotypes in seven species (A-G), and Ad neutralizing antibody (NAb) titres can vary by serotype and geographical location. Until now serotype- and species-specific antibodies have been detected by neutralization or haemagglutination inhibition assays. These expensive and cumbersome methods of adenovirus typing have mainly been used in epidemiological studies. Our prior work demonstrated that NAbs against the fiber protein are commonly generated during natural Ad infection in humans and the trimeric knob is preferentially recognized by fiber-induced NAbs. In this study, we expressed nine trimeric knob proteins from representative Ad serotypes of human Ad (HAdV)-A-F in Escherichia coli and found no cross-reactivity of these recombinant proteins with rabbit hyperimmune sera (among HAdV-A-F or within HAdV-C). Results of the ELISA based on Ad2 and Ad5 (both HAdV-C) knob proteins were consistent with those of neutralization assays, indicating that the trimeric knob protein would be a good candidate antigen for detecting Ad serotype-specific NAbs in sera from naturally infected subjects. We also demonstrated the primary seroepidemiology of nine Ad serotypes in 274 children using the knob-based ELISA. These results have potential implications for epidemiology of Ad serotypes and future development of Ad-based vaccines and gene therapy.

Incidence and treatment strategy for disseminated adenovirus disease after haploidentical stem cell transplantation

Adenovirus (AdV) infection is an emerging complication in patients undergoing allogeneic stem cell transplantation (SCT) and is closely associated with delayed immune reconstitution. In particular, disseminated AdV disease accompanies a high mortality. We retrospectively examined the incidence of AdV infection in patients undergoing unmanipulated haploidentical SCT. Following 121 transplantations in 110 patients, three had asymptomatic AdV viremia, three had localized AdV disease (hemorrhagic cystitis, HC), and seven had disseminated AdV disease (HC + viremia). The median time from transplantation to the onset of AdV-associated HC was 15 days (range 4-39), and the median time to the onset of disseminated AdV disease was 23 days (range 7-38). The cumulative incidence of AdV-associated HC was 8.3 %, and that of disseminated AdV disease was 5.8 %. AdV group B (type 11, type 34, or type 35) was detected in plasma samples from all the patients with disseminated AdV disease. Among them, three patients who received either cidofovir or donor lymphocyte infusion (DLI) alone progressed to pneumonia and died. The remaining four patients were treated with the combination of cidofovir and low-dose unmanipulated DLI, and all survived. We showed that disseminated AdV disease is a significant complication after haplo-SCT and that the combination of cidofovir and DLI is a promising treatment option.

Genotyping of human adenoviruses using a PCR-based reverse line blot hybridisation assay

OBJECTIVES

Human adenoviruses are common pathogens associated with a broad spectrum of disease. There is a growing clinical interest in typing clinical isolates since it is becoming increasingly clear that individual serotypes are associated with different disease spectra, virulence, severity of consequences, and outbreaks. Current methods cannot detect all known adenoviruses simultaneously and rapidly. We designed a practical adenovirus typing method with polymerase chain reaction (PCR)-based reverse line blot hybridisation assay (RLB) using hypervariable region-7 (HVR-7) in the hexon gene.

METHODS

A PCR-RLB assay was developed based on HVR-7 in the hexon region for potentially genotyping 51 adenovirus serotypes by hybridisation of 62 genotype-specific probes using amplicons generated from one genus-specific primer pair. Single PCR and sequencing were performed for confirmation of RLB results. Eighty-seven previously serotyped clinical isolates (representing 28 serotypes) were studied.

RESULTS

Thirty-two different genotypes were detected by RLB from 87 adenovirus isolates, of which 82 isolates showed consistent results with sequencing. Another five isolates revealed evidence by RLB of co-infection, and were confirmed with a combination of genotype-specific single PCR and sequencing.

CONCLUSIONS

In comparison to sequencing and serological methods, the advantages of the RLB assay include: (1) rapid genotyping of multiple samples in a single run; (2) successful detection of co-infection; (3) detection of subgenotype variants. This will allow rapid and inexpensive characterisation of adenovirus infections and outbreaks.

Human adenoviruses in respiratory infections: sequencing of the hexon hypervariable region reveals high sequence variability

BACKGROUND

In respiratory infections, human adenoviruses (hAdV) of species B1 and C are frequently detected, but severe or even fatal disease outbreaks are predominantly caused by only few serotypes. The molecular typing of hAdV hexon sequences can help to speed up the discrimination of serotypes, thus improving on-time epidemiological examinations and patient care.

OBJECTIVES

We aimed to develop a molecular method for the rapid species B1 and C serotype identification in respiratory samples based on sequence generation of the hexon hypervariable region (HVR).

STUDY DESIGN

We developed two PCR-based genotyping systems for a generic HVR amplification and sequence determination of species B1 and C viruses. The assays were applied to hAdV prototypes and 106 samples.

RESULTS

The primer sets proved to be capable of amplifying all B1 and C serotypes. The viruses detected in clinical samples belong to serotypes 1, 2, 3, 5 and 6. The obtained sequences of serotypes 2, 3 and 5 form 2-3 phylogenetic clusters that are based on the characteristic amino acid changes within the variable HVR sites.

CONCLUSIONS

Our assay can significantly speed up the time-span needed for serotype identification and will improve epidemiological surveillance and patient care. The obtained hexon sequences of field viruses vary significantly and form multiple genetic lineages. The variability is focussed on the HVR sites and can be interpreted as the ongoing evolutionary process. Further research is needed on the hexon sequence variability of other (respiratory) hAdV serotypes.

Applications of the polymerase chain reaction in clinical ophthalmology

Molecular biology has become a valuable component in many areas of medicine, including ophthalmology. Polymerase chain reaction (PCR) is the most widely used tool. It has proven to be a powerful technique in diagnosis and quantification of microorganisms and antibiotic resistance screening. For a growing number of ophthalmic conditions PCR testing can be conducted. It is therefore important that clinicians be knowledgeable about the indications, strengths, and limitations of the technique. The purpose of this review is to explore the current role of PCR in the diagnosis and management of eye disease.

Molecular characterization of adenoviral infections in Cuba: report of an unusual association of species D adenoviruses with different clinical syndromes

Adenoviruses are common pathogens that are responsible for a wide variety of infectious syndromes. The objectives of this study were to identify and characterize members of different adenovirus species at the molecular level and to describe the correlation between viruses and clinical syndromes during a period of 4 years. Between 2002 and 2006, 45 of 512 respiratory specimens (8%) from patients with acute respiratory tract infection tested positive for adenovirus. Four adenovirus isolates from samples sent for enterovirus isolation were also analyzed. This research identified 49 confirmed cases of human adenovirus infection by PCR and/or viral culture. The most common diagnosis was upper respiratory infection (44%). Human adenovirusD was the major species found (59%), followed by Human adenovirusC (36%) and Human adenovirusB (4%). Human adenovirus 5 was the major serotype found producing bronchiolitis, followed by human adenovirus 6. In patients with upper respiratory infection, the major serotype found was human adenovirus 17. Viruses of the species Human adenovirusD were identified in seven (77%) cases of acute febrile syndrome. Four isolates from clinical materials obtained from patients with encephalitis, acute flaccid paralysis and meningoencephalitis were identified as belonging to the species Human adenovirusD. Our data demonstrate a surprising result about the identification of an unusual association of viruses of the species Human adenovirusD with different clinical syndromes. This observation could be evaluated as a possible indicator of the emergence of a novel strain but further studies are required.

Adenoviruses: update on structure and function

Adenoviruses have been studied intensively for over 50 years as models of virus-cell interactions and latterly as gene vectors. With the advent of more sophisticated structural analysis techniques the disposition of most of the 13 structural proteins have been defined to a reasonable level. This review seeks to describe the functional properties of these proteins and shows that they all have a part to play in deciding the outcome of an infection and act at every level of the virus's path through the host cell. They are primarily involved in the induction of the different arms of the immune system and a better understanding of their overall properties should lead to more effective ways of combating virus infections.

Molecular epidemiology of adenovirus infection among infants and children with acute gastroenteritis in Dhaka City, Bangladesh

A total of 917 fecal specimens collected from infants and children with acute gastroenteritis in Dhaka City, Bangladesh during 2004-2005 were examined for the presence of adenoviruses by PCR. Adenoviruses were identified in 17 of 917 (1.9%) specimens. Detected adenoviruses were subjected to molecular genetic analysis by sequencing method. Adenoviruses detected in this study were classified into three serotypes, namely Ad9, Ad10 and Ad40. Of these, Ad40 was predominant, followed by Ad9 and accounted for 42% (7 of 17) and 36% (6 of 17), respectively. This is the first report of acute gastroenteritis attributed to Ad9 and Ad10 in Dhaka City, Bangladesh. Another interesting feature of the study was absence of Ad41 serotype. Our results clearly indicated that adenovirus infections were most commonly observed in winter season (October 2004 through January 2005) and in rainy season (May 2005 through July 2005) in Dhaka City. The most common clinical symptoms of adenovirus-infected patients were dehydration (94%), abdominal pain (59%) and vomiting (30%). To our knowledge, this is the first 1-year molecular epidemiological research of adenovirus infection in Bangladesh.

Outbreak of acute respiratory disease in China caused by B2 species of adenovirus type 11

An outbreak of acute respiratory tract infection occurred in Shanxi Province, China, from March to April 2006. Of the 254 patients affected by this outbreak, 247 patients were students of a senior high school; 1 of these patients died during the outbreak. Serological tests and blood culture revealed no evidence of bacterial infection. The results of direct reverse transcription-PCR or PCR performed with clinical specimens collected from the patients, including the sole patient who died, were positive for human adenoviruses (HAdVs) but negative for influenza virus, measles virus, rubella virus, mumps virus, parainfluenza virus, respiratory syncytial virus, and human enteroviruses. These findings were confirmed by enzyme-linked immunosorbent assay for HAdV immunoglobulin A, the conventional neutralization test, and viral isolation and identification. Sequencing of the entire hexon gene revealed that HdAV type 11a (HAdV-11a) belonging to the B2 species of HAdV was the etiological agent responsible for the outbreak. However, both the analysis of the phylogenetic relationship and the similarity plot indicated that the sequence of the 3' end of the hexon gene outside the hypervariable regions the HAdV-11a strain isolated in this outbreak may be a recombinant with the sequence of the HAdV-14 strain of species B2. Although isolates of HAdV species B2 seldom cause respiratory infections, they may pose a new global challenge with regard to acute respiratory diseases; this possibility cannot be overlooked and should be carefully considered. Hence, the need to establish and improve both epidemiological and virological surveillance of HAdV infections in China should be emphasized.

Adenoviruses C in non-hospitalized Mexican children older than five years of age with acute respiratory infection

Adenoviruses (AdV) are commonly involved in acute respiratory infections (ARI), which cause high morbidity and mortality in children. AdV are grouped in six species (A-F), which are associated with a wide range of diseases. The aim of this study was to identify the AdV species infecting non-hospitalized Mexican children with ARI symptoms, attending to the same school. For that, a PCR/RFLP assay was designed for a region of the hexon gene, which was chosen, based on the bioinformatical analysis of AdV genomes obtained from GenBank. A total of 100 children's nasopharyngeal samples were collected from January to June, 2005, and used for viral isolation in A549 cells and PCR/RFLP analysis. Only 15 samples produced cytopathic effect, and in all of them AdV C was identified. AdV C was also identified in eight additional nasopharyngeal samples which were negative for viral isolation. In summary, this outpatient population showed a rate of AdV infection of 23%, and only AdV C was detected.

Nosocomial outbreak of epidemic keratoconjunctivitis accompanying environmental contamination with adenoviruses

An outbreak of acute keratoconjunctivitis involving 27 patients occurred in the Department of Ophthalmology, Kurume University Hospital. Adenoviral DNA was detected in four inpatients, one outpatient and one healthcare worker. Sequence-based typing of adenoviral DNA indicated serotype 3 from one inpatient, the rest being serotype 37. At a later stage of the outbreak adenoviral DNA types 37 and/or 3 were also detected from almost all environmental instruments and commonly used eye drops, despite thorough disinfection of the environment and enforcement of various infection control measures. The detection rate of adenoviral DNA in environmental swabs was 81%. A further second disinfection of the environment reduced the detection rate of adenoviral DNA to 38%. The outbreak ceased after closing the ophthalmology ward and outpatient consulting room, accompanied by enhanced cleaning of environmental instruments and the introduction of disposable eye drops for individual patients.

Rapid detection of oculopathogenic adenovirus in conjunctivitis

Ocular adenovirus (Ad) infections occur throughout the world in both sporadic and epidemic forms. Accurate laboratory diagnosis of Ad in conjunctival samples is always valuable. The present study was carried out to explore the presence of Ad as a causative agent in clinically suspected viral conjunctivitis and to compare the performance of conventional virus isolation on cell cultures, direct detection of Ad antigens in conjunctival cells by a direct fluorescence assay, Ad DNA detection by polymerase chain reaction (PCR), and specific IgM measurement by ELISA. Samples included scrapes from conjunctiva. Scrapes were subjected to study by direct immunofluorescence stain, culture on the Hep-2 cell line, and PCR for Ad detection. Blood samples were also taken and subjected to study for specific anti-Ad IgM determination. The culture for Ad was positive in 77.8%, direct antigen detection by fluorescent stain was positive in 72.2%, PCR was positive in 83.3%, and serology was positive in 88.9% of patients. Both determination of antibody IgM and PCR correctly identified a larger group of patients compared to cell culture. The most sensitive and specific method for diagnosis of Ad compared to culture was PCR (100%), followed by IgM detection (92.9%) then direct antigen detection by fluorescent stain (85.8%). From this study, we conclude that Ad is a common pathogen in sporadic cases of conjunctivitis. Screening of adenoviral conjunctivitis is possible by using specific IgM due to its high sensitivity. A confirmatory test can be done by PCR for diagnosis of Ad, as it is a rapid, specific, and accurate method.

The prevalence of adenoviral conjunctivitis at the Wills Eye Hospital Emergency Room

OBJECTIVE

The aim of this study was to evaluate the prevalence of adenoviral conjunctivitis by analyzing data from a prospective clinical study of 50 consecutive patients presenting to the Wills Eye Hospital Emergency Room (WEH ER) with a clinical diagnosis of infectious conjunctivitis from July 2003 to October 2003.

METHODS

The polymerase chain reaction (PCR) was used to evaluate all cases of clinically diagnosed infectious conjunctivitis. Based on the laboratory findings, the prevalence of adenovirus was determined.

RESULTS

Of the 50 consecutive patients with acute infectious conjunctivitis, 31 patients were PCR positive for adenovirus.

CONCLUSIONS

The prevalence of adenoviral conjunctivitis was found by PCR to represent 62% of all patients presenting with a clinical diagnosis of infectious conjunctivitis from July 2003 to October 2003.

Oligonucleotide microarray design for detection and serotyping of human respiratory adenoviruses by using a virtual amplicon retrieval software

The rapid development of new molecular biology methods has improved infectious disease diagnosis, which is increasingly important to clinical management and public health. A wide variety of new methods which are more specific, sensitive and robust, such as combination of PCR and microarray technology, has gradually replaced the conventional assays usually used in routine diagnosis. Both methods have the advantage of speed and sensitivity but tend to be expensive and technically demanding. Therefore, it is necessary to develop more simple assays that could be available for all diagnostic laboratories. To this aim, a simple microarray assay for detection and typing of adenoviruses causing acute respiratory disease in humans was developed. The absence of effective therapeutic or alternative prophylactic treatment for this infection makes essential its rapid diagnosis to implement fast control measures. Moreover, the family Adenoviridae includes numerous serotype groups and constitutes an ideal model system to develop diagnostic methods for other human pathogens. For their precise identification, an amplicon retrieval software that simplifies and accelerates the processing of all sequences necessary to perform this type of experiments has also been developed. This new technology was applied for the simultaneous detection and serotyping of acute respiratory disease-causing adenoviruses in laboratory and clinical samples with efficiency and accuracy.

Adenovirus infection after allogeneic stem cell transplantation

Adenovirus infection after allogeneic hematopoietic stem cell transplantation (HSCT) is an emerging pathogen causing relevant morbidity and mortality, with preponderance in children. During the last years, basic research on the biology of the virus and host immune response ameliorated the diagnostic, surveillance, and therapeutic strategies. Risk factors for infection commonly have an impact on T-cell reconstitution, such as T-cell depleted graft, unrelated or HLA-mismatched donor transplantation, and GvHD. Weekly surveillance by PCR in stool and blood till day 100 or longer post-HSCT and pre-emptive therapy with cidofovir are the mainstay of the current approach to adenoviral infections post-HSCT. Since a sufficient host T-cell response is essential to clear the virus, diagnostic procedures for detection of virus-specific T-cells have recently been developed to assess the risk of the infection. Furthermore, adoptive immunotherapy is a new treatment option for patients with absent specific T-cell response and present systemic adenoviral infection.

An outbreak of adenovirus serotype 41 infection in infants and children with acute gastroenteritis in Maizuru City, Japan

A total of 337 fecal specimens were collected from infants and children with acute gastroenteritis in Maizuru City, Japan from July 2004 to June 2005 and tested for the presence of rotavirus, norovirus, sapovirus, astrovirus, and adenovirus by RT-multiplex PCR. Among diarrheal viruses detected, norovirus was the most prevalent (13.6%, 46 of 337), followed by adenovirus (8%, 27 of 337), group A rotavirus (5%, 17 of 337), astrovirus (1.8%, 6 of 337), and sapovirus (1.8%, 6 of 337), respectively. Adenovirus was subjected to molecular genetic analysis by sequencing. Adenovirus detected in this study was classified into five serotypes, namely Ad1, Ad2, Ad3, Ad5, and Ad41. Of these, Ad41 was the most predominant serotype that accounted for 85.2% (23 of 27). It was noteworthy to point out that Ad41 infection was apparently confined only to the period of 4 months (October 2004 through January 2005). This pattern of infection implied the outbreak of Ad41 in these subjects, which was the first outbreak of acute gastroenteritis attributed to adenovirus in Maizuru City, Japan. Another interesting feature of the study was the existence of two Ad41 subtypes co-circulating in this outbreak. This report confirmed the presence of adenovirus as one of an important cause of acute gastroenteritis among Japanese infants and children.

Isolation and identification of adenovirus from conjunctival scrapings over a two-year period (between 2001 and 2003) in Yokohama, Japan

Over a 2-year period between 2001 and 2003, a total of 115 conjunctival scrapings were collected from patients with keratoconjuctivitis from several hospitals in Yokohama, Japan. Out of 115, 94 (82.4%) cases of adenoviruses were detected by polymerase chain reaction (PCR); 60 (52.1%) by cell culture isolation; and 16 (14.0%) by enzyme-linked immunosorbent assay (ELISA). The serotypes were determined by PCR- restriction fragment length polymorphism analysis (PCR-RFLP) and by the neutralization test (NT). PCR-RFLP was performed using a combination of endonucleases such as HhaI, AluI, and HaeIII. Of the 94 PCR-positive samples, the serotypes of 91 (96.8%) were identified by PCR-RFLP analysis (adenovirus 3: 50%, 4: 11%, and 8: 32%). Out of the 115 samples, 60 samples were identified by the neutralization (adenovirus 3, 4, 7, and 8). When both PCR-RFLP and the neutralization techniques were used, 53.2%, 11.7%, 1.1%, and 34% of the samples were identified as adenovirus 3, 4, 7, and 8, respectively. In contrast to the results of a nationwide surveillance report, adenovirus 3 was found as a major cause of keratoconjunctivitis in the Yokohama area. The nationwide surveillance report did not reflect accurately the epidemiological situation in the local area. In order to obtain surveillance data that would be useful for the prevention of an adenovirus conjunctivitis epidemic, it seems that local epidemiology is more important than that nationwide surveillance.

Quantitative detection and rapid identification of human adenoviruses

We have established a method of quantitative detection and rapid identification of human adenoviruses (hAdVs). Using LightCycler PCR with a primer set, we were able to amplify 554 bp of the hexon gene from each of 51 prototype strains of hAdVs. The sensitivity of LightCycler PCR was 10 copies of hAdV DNA/reaction. When LightCycler PCR was performed using a set of primers, hAdV was positive for 74.4% (99 of 133) of conjunctivitis patients and for 27.3% (81 of 297) of respiratory infection patients. We also attempted to measure hAdV in the potentially contaminated eye drops used by patients, detecting 5.4 x 10(2) to 1.6 x 10(6) copies/ml of hAdV. We determined the 350-bp nucleotide sequence of the amplified hexon gene and compared it with the sequences of the 51 prototype strains. Phylogenetic analysis based on 350 bp of the hexon gene identified 99 positive conjunctival swabs as 24 cases of AdV type 3 (AdV-3), 14 cases of AdV-4, 1 case of AdV-8, 19 cases of AdV-19a, and 41 cases of AdV-37. The 81 sequences from pharyngeal or nasal mucus swabs were identified as 29 cases of AdV-2, 18 cases of AdV-1, 18 cases of AdV-5, 12 cases of AdV-4, 2 cases of AdV-37, 1 case of AdV-3, and 1 case of AdV-6. LightCycler PCR followed by phylogenetic analysis provides an effective tool for the rapid identification of hAdVs and for studying molecular epidemiology.

Prevalence and characterization of enteric adenoviruses in the South of Ireland

Enteric adenoviruses have been shown to be a substantial cause of pediatric gastroenteritis in various parts of the world, and are considered to be the second most common cause of viral gastroenteritis, next to rotavirus in young children. Genetic characterization of 95 adenovirus isolates obtained from patients with acute gastroenteritis between 2002 and 2007 from the southern regions of Ireland, were characterized by PCR analysis, restriction endonuclease (RE) analysis and sequencing analysis. All isolates were found to be of adenovirus type 41 origin. Genetic analysis of seven hypervariable regions (HVRs) located within the hexon gene has revealed a high level of amino acid sequence homology in samples over the course of this study, with a very close relationship to the D22 genome type. The D22 genome type has been detected in several other countries, thus suggesting Irish isolates have common genome types with other stains worldwide. This is the first such study undertaken in the south of Ireland, to type and genetically characterize adenoviral gastroenteritis isolates, and has revealed a high level of conservation within the isolated analyzed.

Typing of human adenoviruses in specimens from immunosuppressed patients by PCR-fragment length analysis and real-time quantitative PCR

Currently, 51 human adenovirus (AdV) serotypes, which are divided into six species (A to F), are known. AdV infections are a major cause of morbidity and mortality in immunosuppressed individuals, particularly in allogeneic stem cell transplant (SCT) recipients. Any AdV species may cause life-threatening disease, but little information is available on the clinical relevance of individual serotypes. The use of serological testing for serotype identification is limited due to the impaired immune response during the posttransplant period. A new molecular approach to serotype identification is presented here that exploits variable regions within the hexon gene. All serotypes belonging to the species A, B, C, E, and F can be determined by fragment length analysis of a single PCR product. For species C, which is the most prevalent in many geographic regions, an alternative technique based on serotype-specific real-time quantitative PCR was established. Of 135 consecutive pediatric patients screened for AdV infections after allogeneic SCT, 40 tested positive. Detailed analysis revealed the presence of 10 different serotypes; serotypes 1 and 2 from species C (C01 and C02) showed the highest prevalence, accounting for 77% of the AdV-positive cases. Representatives of other species were observed less commonly: serotype A12 in 6.5%; serotype A31 in 4.5%; and B03, B16, C05, C06, D19, and F41 in 2%. The approach to rapid molecular serotype analysis presented here provides a basis for detailed studies on adenovirus epidemiology and on the transmission of nosocomial infections. Moreover, in view of the increasing importance of tailored therapy approaches, serotype identification may in the future have implications for the selection of the most appropriate antiviral treatment.

Molecular epidemiology of adenovirus isolates from patients diagnosed with intussusception in Melbourne, Australia

Twenty-one intussusception (IS)-associated and 59 temporally linked adenoviral isolates from clinical infections were compared. Species C (15/21 IS- and 32/59 non-IS-associated isolates) dominated. Of these, serotype 2 (AdV-2) (7/15 IS-associated isolates) and serotype 1 (AdV-1) (16/32 non-IS-associated isolates) were the most commonly identified serotypes. DNA restriction analysis of AdV-2 isolates identified six genomic types; of these, type D2 (3/7 IS- and 8/11 non-IS-associated isolates) was the dominant type after BamHI and SmaI digestion. IS-associated isolates are similar to circulating non-IS-associated strains.

The RPS adeno detector for diagnosing adenoviral conjunctivitis

PURPOSE

To compare the sensitivity, specificity, and accuracy of the RPS Adeno Detector (Rapid Pathogen Screening Inc., South Williamsport, PA) against both viral cell culture with confirmatory immunofluorescence staining (CC-IFA) and the polymerase chain reaction (PCR) for diagnosing adenoviral conjunctivitis.

DESIGN

Prospective, nonrandomized, masked, multicenter clinical trial.

PARTICIPANTS

One hundred eighty-six consecutive patients from 5 clinical centers seeking treatment within 1 week of developing a red eye and thought to have acute conjunctivitis.

METHODS

The RPS Adeno Detector is a 10-minute in-office lateral flow immunoassay. Patients were tested with the RPS Adeno Detector, CC-IFA, and PCR to detect the presence of adenovirus.

MAIN OUTCOME MEASURES

The sensitivity, specificity, and accuracy of the RPS Adeno Detector were assessed for identifying cases of adenoviral conjunctivitis.

RESULTS

Compared with CC-IFA, the RPS Adeno Detector was 88% sensitive and 91% specific at detecting adenoviral conjunctivitis. Using PCR as a reference method, the sensitivity of the RPS Adeno Detector increased to 89% and the specificity increased to 94%. Compared with PCR, CC-IFA was found to be 91% as sensitive and 100% as specific.

CONCLUSIONS

The RPS Adeno Detector demonstrated sufficient sensitivity and specificity to be used in the physician's office for the detection of adenoviral conjunctivitis.

Detection and sequence-based typing of human adenoviruses using sensitive universal primer sets for the hexon gene

The universal primer sets for identification of human adenovirus (HAdV) targeting hexon gene were designed and applied to 121 clinical samples suspected of HAdV infection. The primer sets amplified at least 20 HAdV reference strains of six species. Of these clinical samples, 81 (66.9%) samples were positive for HAdV. They were classified into 11 serotypes belonging to 5 HAdV species (B-F). The primer sets described here are sensitive and reactive to the broad spectrum of HAdV and are useful for rapid diagnosis of various HAdV infections.

Molecular typing of human adenoviruses by PCR and sequencing of a partial region of the hexon gene

Human adenoviruses (Ads) are responsible for a substantial disease burden. Type-specific identification of Ads can help guide therapeutic and disease prevention strategies and aid epidemiological investigations. Immunotyping of Ads by serum neutralization (SN) is laborious and time consuming and depends upon type-specific antisera that are in short supply. A rapid molecular typing assay based on polymerase chain reaction (PCR) amplification and sequencing of Ad hexon gene hyper-variable regions 1-6 (HVR(1-6)) known to contain type-specific epitopes was evaluated as an alternative to SN. Deduced amino acid sequences of HVR(1-6) obtained from all 51 currently recognized Ad prototype strains were well resolved, with the exception of types 15 and 29, which were identical. Of 192 temporally and geographically diverse Ad field isolates sequenced in this study, and 111 previously published sequences, all more closely matched their predicted prototype strains. Ads were also detected and correctly identified directly from 24 clinical specimens positive by culture or antigen detection. PCR and sequencing of HVR(1-6) offers a practical alternative to SN for typing most Ads and can be readily adapted for use in laboratories with molecular capabilities.

Rapid identification of human adenovirus types 3 and 7 from respiratory specimens via multiplex type-specific PCR

The rapid diagnosis of human adenovirus (Ad) infection is crucial for the timely recognition of epidemics. Moreover, identification of the serotypes known to cause serious disease can be helpful in therapeutic intervention. A multiplex PCR assay was developed for the rapid detection of adenovirus type 3 (Ad3) and Ad7 directly from clinical specimens. For this assay, three primer pairs (primers were based on the conserved and hypervariable regions of the hexon) were designed in order to simultaneously amplify all adenoviral serotypes and discriminate between Ad3 and Ad7. In our preliminary analysis, this multiplex PCR assay generated amplicons of the consensus primers from all 106 adenoviral isolates of diverse serotypes and proved able to correctly identify Ad3 and Ad7. This assay was subsequently applied to the detection of Ad3 and Ad7 in respiratory specimens. Among the 127 nasal aspirates from which an adenovirus was grown, the sensitivity with which any serotype could be detected was 91% (115/127). Two of the 53 nasal aspirates which did not grow Ads yielded adenovirus-specific bands, which were confirmed by sequencing analysis. Among the 115 specimens which produced common adenoviral bands, the sensitivity with which Ad3 could be detected was 93% (26/28), and the sensitivity with which Ad7 could be detected was 100% (35/35). Five out of the 115 specimens were proved to harbor more than one type of Ad via sequencing analysis of the amplicons, suggesting mixed infection with at least two different serotypes. In conclusion, this multiplex PCR system can be utilized in the rapid identification of Ad3 and Ad7 directly from clinical specimens. Furthermore, this method constitutes a diagnostic strategy for the detection of coinfection by different Ad serotypes.

Respiratory disease caused by a species B2 adenovirus in a military camp in Turkey

In April 2004, two patients were admitted to hospital in Berlin, Germany, with clinical signs of acute respiratory infection after returning from a military exercise in their home country of Turkey. They were admitted to a high security infectious disease unit as epidemiological data pointed to an outbreak of unknown etiology. Samples taken at the time of admission proved to be strongly positive for Adenovirus by PCR, but negative for Influenza A/H1N1 virus, Influenza A/H3N2 virus, Influenza B virus, Respiratory syncytial virus, and SARS coronavirus. No evidence for bacterial infection was obtained by serological tests and blood cultures. The adenovirus detected was characterized further by genotyping and was identified as a species B2 virus with the highest similarity to adenovirus type 11a.