An Old Acquaintance: Could Adenoviruses Be Our Next Pandemic Threat?

Human adenoviruses (HAdV) are one of the most important pathogens detected in acute respiratory diseases in pediatrics and immunocompromised patients. In 1953, Wallace Rowe described it for the first time in oropharyngeal lymphatic tissue. To date, more than 110 types of HAdV have been described, with different cellular tropisms. They can cause respiratory and gastrointestinal symptoms, even urinary tract inflammation, although most infections are asymptomatic. However, there is a population at risk that can develop serious and even lethal conditions. These viruses have a double-stranded DNA genome, 25-48 kbp, 90 nm in diameter, without a mantle, are stable in the environment, and resistant to fat-soluble detergents. Currently the diagnosis is made with lateral flow immunochromatography or molecular biology through a polymerase chain reaction. This review aimed to highlight the HAdV variability and the pandemic potential that a HAdV3 and 7 recombinant could have considering the aggressive outbreaks produced in health facilities. Herein, we described the characteristics of HAdV, from the infection to treatment, vaccine development, and the evaluation of the social determinants of health associated with HAdV, suggesting the necessary measures for future sanitary control to prevent disasters such as the SARS-CoV-2 pandemic, with an emphasis on the use of recombinant AdV vaccines to control other potential pandemics.

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.

Make Sure You Have a Safety Net: Updates in the Prevention and Management of Infectious Complications in Stem Cell Transplant Recipients

Hematopoietic stem cell transplant recipients are at increased risk of infection and immune dysregulation due to reception of cytotoxic chemotherapy; development of graft versus host disease, which necessitates treatment with immunosuppressive medications; and placement of invasive catheters. The prevention and management of infections in these vulnerable hosts is of utmost importance and a key “safety net” in stem cell transplantation. In this review, we provide updates on the prevention and management of CMV infection; invasive fungal infections; bacterial infections; Clostridium difficile infection; and EBV, HHV-6, adenovirus and BK infections. We discuss novel drugs, such as letermovir, isavuconazole, meropenem-vaborbactam and bezlotoxumab; weigh the pros and cons of using fluoroquinolone prophylaxis during neutropenia after stem cell transplantation; and provide updates on important viral infections after hematopoietic stem cell transplant (HSCT). Optimizing the prevention and management of infectious diseases by using the best available evidence will contribute to better outcomes for stem cell transplant recipients, and provide the best possible “safety net” for these immunocompromised hosts.

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.

Respiratory Infections in the U.S. Military: Recent Experience and Control

This comprehensive review outlines the impact of military-relevant respiratory infections, with special attention to recruit training environments, influenza pandemics in 1918 to 1919 and 2009 to 2010, and peacetime operations and conflicts in the past 25 years. Outbreaks and epidemiologic investigations of viral and bacterial infections among high-risk groups are presented, including (i) experience by recruits at training centers, (ii) impact on advanced trainees in special settings, (iii) morbidity sustained by shipboard personnel at sea, and (iv) experience of deployed personnel. Utilizing a pathogen-by-pathogen approach, we examine (i) epidemiology, (ii) impact in terms of morbidity and operational readiness, (iii) clinical presentation and outbreak potential, (iv) diagnostic modalities, (v) treatment approaches, and (vi) vaccine and other control measures. We also outline military-specific initiatives in (i) surveillance, (ii) vaccine development and policy, (iii) novel influenza and coronavirus diagnostic test development and surveillance methods, (iv) influenza virus transmission and severity prediction modeling efforts, and (v) evaluation and implementation of nonvaccine, nonpharmacologic interventions.

A cost effective real-time PCR for the detection of adenovirus from viral swabs

Compared to traditional testing strategies, nucleic acid amplification tests such as real-time PCR offer many advantages for the detection of human adenoviruses. However, commercial assays are expensive and cost prohibitive for many clinical laboratories. To overcome fiscal challenges, a cost effective strategy was developed using a combination of homogenization and heat treatment with an “in-house” real-time PCR. In 196 swabs submitted for adenovirus detection, this crude extraction method showed performance characteristics equivalent to viral DNA obtained from a commercial nucleic acid extraction. In addition, the in-house real-time PCR outperformed traditional testing strategies using virus culture, with sensitivities of 100% and 69.2%, respectively. Overall, the combination of homogenization and heat treatment with a sensitive in-house real-time PCR provides accurate results at a cost comparable to viral culture.

Two adenovirus serotype 3 outbreaks associated with febrile respiratory disease and pharyngoconjunctival fever in children under 15 years of age in Hangzhou, China, during 2011

Adenovirus serotype 3 and 7 outbreaks have occurred periodically in northern, eastern, and southern China since 1955, but there has been no report since the adenovirus serotype 7 outbreak first occurred in Hangzhou, China, in 1991. Here we explored the epidemiology and etiology of two adenovirus serotype 3 outbreaks in Hangzhou in 2011. One acute respiratory outbreak was found in Chun'an County, where a total of 371 cases were confirmed in 5 of 23 towns from 4 to 31 May 2011. The outbreak affected 18.57% (13/70) of schools and 14.49% (90/621) of classes. The incidence was 5.18% (371/7,163). The population was distributed among individuals ages 7 to 15 years. No parents or teachers were infected. Another pharyngoconjunctival fever outbreak was discovered in the Chenjinglun Swimming Center located in the Xihu District between 1 and 15 July 2011. A total of 134 cases were confirmed in 900 amateur swimmers, with an incidence of 14.89% (134/900). The ages ranged from 4 to 9 years. The two outbreaks had no severe complications or death. The viruses in 66.67% (10/15) of throat swabs from children with acute respiratory infections and 100% (10/10) of the swabs from children with pharyngoconjunctival fever were confirmed to be adenovirus serotype 3 with 100% homology by PCR. Of these samples, 60.0% (12/20) had a classical characteristic cytopathic effect, presented as grape-like clusters at 72 h after infection in HEp-2 cells. In conclusion, the acute respiratory infection and pharyngoconjunctival fever outbreak in Hangzhou were caused by the completely homologous type 3 adenovirus in subgenus B. Moreover, these outbreaks demonstrated rapid transmission rates, possibly due to close contact and droplet transmission.

Viral pneumonias in immunocompromised adult hosts

Viral infections have always been considered pediatric diseases. However, viral pneumonia has become an important cause of morbidity and mortality in immuncompromised adults. Improved diagnostic techniques, such as the introduction of highly sensitive nucleic acid amplification tests, have not only allowed us to discover new viruses but also to determine the etiology of viral pneumonia in immunocompromised adult hosts. Unfortunately, only a few antiviral agents are available. Thus, early diagnosis and treatment are crucial to patient outcome. In this article, we review the most common viruses that have been implicated as etiologic agents of viral pneumonia in immunocompromised adults. We discuss the epidemiologic characteristics and clinical presentation of these viral infections and the most appropriate diagnostic approaches and therapies when available.

Multiplexed Luminex xMAP assay for detection and identification of five adenovirus serotypes associated with epidemics of respiratory disease in adults

Several serotypes of human adenovirus (HAdV) cause acute respiratory disease (ARD) among healthy adults, sometimes generating broad outbreaks with high attack rates and occasional fatalities. Timely serotype identification provides valuable epidemiological information and significantly contributes to prevention (vaccination) strategies. The prevalence of specific serotypes causing ARD varies geographically. HAdV-3, HAdV-4, HAdV-7, HAdV-14, and HAdV-21 are the serotypes most commonly found in adult populations in the Western Hemisphere. Unfortunately, conventional serotype identification is a tedious process which can take a week or longer. For this reason, new molecular methods for serotype identification are needed. Commercially available rapid antigen and PCR assays for the detection of HAdV are universal but do not distinguish between the different serotypes. We describe the development of a sensitive and specific multiplex assay capable of identifying serotypes 3, 4, 7, 14, and 21. Two sets of primers were used for nonspecific (universal) PCR amplification, and serotype-specific probes coupled to Luminex tags were used for target-specific extension (TSE). PCR and TSE primers were designed using known hexon gene sequences of HAdV. The TSE products of HAdV-3, HAdV-4, HAdV-7, HAdV-14, and HAdV-21 were correctly identified using the Luminex xMAP fluid microsphere-based array system. No cross-reactivity with other respiratory pathogens or other HAdV serotypes was observed. This multiplexed assay can be expanded to include more serotypes and will allow broad and rapid detection and identification of adenoviral serotypes in a high-throughput environment.

Development of duplex real-time PCR for detection of two DNA respiratory viruses

A method was developed for the detection and quantitation of HAdV (human adenovirus) and HBoV (human bocavirus) based on a duplex real-time PCR, the AB PCR, using a Smartcycler instrument. A control real-time PCR was carried out on albumin DNA to standardise the non-homogenous respiratory samples. No cross-reactivity was observed with viruses or bacteria that could be found in the respiratory tract. The diagnosis rate using the AB PCR on clinical samples was 10.7%: 3.4% for HBoV detection, 6.9% for HAdV detection and 0.3% double detection HBoV-HAdV. The clinical and epidemiological characteristics of the HAdV- and HBoV-infected patients were evaluated. In the HAdV-positive group and the HBoV-positive group the samples were classified according to the severity of the disease. The HAdV viral load did not appear to be linked to the severity of the disease. Conversely, the difference between the two HBoV groups, severe and non-severe, was significant statistically when the comparison was based on the viral load (P=0.006) or after adjustment of the viral load to the number of cells in the samples (P=0.02).

Duplex-PCR assay for the detection of adenovirus and respiratory syncytial virus in nasopharyngeal samples

Human adenovirus (HAdV) and human respiratory syncytial virus (HRSV) are important etiologic agents of acute respiratory infections. In this study, a duplex polymerase chain reaction (PCR) assay was developed for the simultaneous detection of HAdV and HRSV in clinical samples. Sixty previously screened nasopharyngeal aspirates were used: 20 HAdV-positive, 20 HRSV-positive and 20 double-negative controls. Eight samples were positive for both viruses. The duplex PCR assay proved to be as sensitive and specific as single-target assays and also detected the mixed infections with certainty. The identification of both viruses in a single reaction offers a reduction in both cost and laboratory diagnostic time.

Viral infections in patients with chronic obstructive pulmonary disease

PURPOSE OF REVIEW

Chronic obstructive pulmonary disease is a major cause of morbidity and mortality worldwide. There is increasing evidence that implicates viral infections as a major risk factor for exacerbations of chronic obstructive pulmonary disease. Recent studies have attempted to better characterize the epidemiology of viral infections in chronic obstructive pulmonary disease, identify unique clinical manifestations of virus-associated exacerbations, and develop new diagnostic tools and treatments.

RECENT FINDINGS

Rhinovirus, the organism most often responsible for causing the common cold, is also the most common infectious cause of chronic obstructive pulmonary disease exacerbations. Coronavirus, influenza, respiratory syncytial virus, parainfluenza, adenovirus, and metapneumovirus are other important viral causes of chronic obstructive pulmonary disease exacerbations. These exacerbations can be severe with prolonged recovery times. Although PCR technology has dramatically increased the detection rate of viruses in patients with chronic obstructive pulmonary disease, it does not differentiate infection from colonization. The use of biomarkers represents an exciting new potential diagnostic tool that may lend new insights into the pathogenesis of viral infections in patients with chronic obstructive pulmonary disease.

SUMMARY

Despite strong epidemiologic evidence linking respiratory virus infection to exacerbations of chronic obstructive pulmonary disease, many of the cellular and molecular mechanisms by which viruses cause exacerbations remain undetermined. Future research efforts to understand these mechanisms would aid the development of novel therapeutics to reduce the morbidity and mortality of this disease.

Currently used nucleic acid amplification tests for the detection of viruses and atypicals in acute respiratory infections

For the detection of respiratory viruses conventional culture techniques are still considered as the gold standard. However, results are mostly available too late to have an impact on patient management. The latest developments include appropriate DNA- and RNA-based amplification techniques (both NASBA and PCR) for the detection of an extended number of agents responsible for LRTI. Real time amplification, the latest technical progress, produces, within a considerable shorter time, results with a lower risk of false positives. As results can be obtained within the same day, patient management with appropriate therapy or reduction of unnecessary antibiotic therapy in LRTI will be possible. A number of technical aspects of these amplification assays, and their advantages are discussed.

The availability and use of these new diagnostic tools in virology has contributed to a better understanding of the role of respiratory viruses in LRTI. The increasing importance of the viral agents, Mycoplasma pneumoniae and Chlamydophila pneumoniae in ARI is illustrated. A great proportion of ARI are caused by viruses, but their relative importance depends on the spectrum of agents covered by the diagnostic techniques and on the populations studied, the geographical location and the season. The discovery of new viruses is ongoing; examples are the hMPV and the increasing number of coronaviruses. Indications for the use of these rapid techniques in different clinical situations are discussed. Depending on the possibilities, the laboratory could optimize its diagnostic strategy by applying a combination of immunofluorescence for the detection of RSV an IFL, and a combination of real-time amplification tests for other respiratory viruses and the atypical agents. When implementing a strategy, a compromise between sensitivity, clinical utility, turn around time and cost will have to be found.

Diagnostic evaluation of mononucleosis-like illnesses

Clinicians face a diagnostic challenge when a patient with the classic fever, pharyngitis, and lymphadenopathy triad of infectious mononucleosis has a negative "spot" heterophile antibody test. This screening test, although commonly considered sensitive for the presence of Epstein-Barr virus (EBV) infection, may be negative early after infection. A growing number of pathogens have been reported to cause heterophile-negative mononucleosis-like illnesses, including cytomegalovirus (CMV), human herpesvirus 6 (HHV-6), human immunodeficiency virus (HIV), adenovirus, herpes simplex virus (HSV), Streptococcus pyogenes, and Toxoplasma gondii. Other infectious and noninfectious disorders also may present in ways that mimic mononucleosis, but fail to generate EBV's archetypal triad of clinical findings. A systematic approach to the diagnosis of mononucleosis-like illnesses ensures that conditions warranting specific therapy are distinguished from others requiring only supportive care.

Adenovirus infections in transplant recipients

Adenoviruses are increasingly recognized as contributors to morbidity and mortality among stem cell and solid-organ transplant recipients. Clinical presentations range from asymptomatic viremia to respiratory and gastrointestinal disease, hemorrhagic cystitis, and severe disseminated illness. The limited clinical data available support the use of cidofovir for many of these illnesses. Prospective studies are needed to better understand the pathogenesis of and therapeutic options for adenoviral infections in this patient population.

Presence of viral and bacterial pathogens in the nasopharynx of otitis-prone children. A prospective study

OBJECTIVE

The purpose of the present study was to examine and follow up the presence of respiratory viral and bacterial pathogens in the nasopharynx of otitis-prone children during the cold season and compare the findings with the child's respiratory symptoms.

METHODS

We enrolled 121 otitis-prone children, aged 10 months to 4 years for a prospective study. The nasopharyngeal swab (NPS) were studied at the baseline and after 12 and 24 weeks for respiratory viruses and at the baseline and after 24 weeks for bacteria. Presence of picorna(rhino-entero-parecho)-, influenza-, adenoviruses and Mycoplasma pneumoniae was detected by PCR. NPS specimens were cultured for Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis. Clinical data (the rate of respiratory symptom days, otitis media, tympanometry findings, day-care attendance and the number of siblings) were compared with microbiological data.

RESULTS

Rhinovirus was found in 30% of the samples at the baseline, in 8% and in 19% of the samples after 12 and 24 weeks, respectively. Enterovirus was detected in 19% of the samples, in 21% and in 12% of samples after 12 and 24 weeks, respectively. Picornavirus positivity correlated with the respiratory symptoms but not with the number of otitis media or with abnormal tympanometry. Two samples were adeno- and three samples influenzavirus positive. Parechovirus and M. pneumoniae were negative in all samples. Rhinovirus positivity correlated with that of M. catarrhalis and S. pneumonia but not with H. influenzae. Microbiological positivity was not significantly associated with the type of day-care.

CONCLUSIONS

Picornaviruses as well as bacteria were commonly found in the nasopharynx of otitis-prone children during the cold season, even in the absence of clinical symptoms.

Disseminated adenovirus infection with respiratory failure in pediatric liver transplant recipients: impact of intravenous cidofovir and inhaled nitric oxide

Adenoviruses (AdV) are opportunistic pathogens that can lead to severe infections and respiratory failure (acute respiratory distress syndrome, ARDS) with high mortality in immunosuppressed patients. Cidofovir (CDV) has been used in adenoviral disease in bone marrow transplant recipients. Two pediatric liver transplant recipients with disseminated adenoviral disease and ARDS were treated with reduction of immunosuppression, CDV, and inhaled nitric oxide (iNO). CDV 1 mg/kg was given three times per week intravenously with intravenous hydration and oral probenecid. Viral suppression and clinical improvement was achieved. AdV hepatitis did not occur, and graft function was preserved, although acute rejection occurred in both patients. Adverse effects were mild and transient not requiring dose modification. Severe hypoxemia was reversed with iNO 10-20 p.p.m. CDV treatment of AdV infections in organ transplant recipients and other immunocompromised patients should be further investigated in prospective studies.

Sample type is crucial to the diagnosis of Mycoplasma pneumoniae pneumonia by PCR

Sensitive and specific methods for rapid laboratory diagnosis of Mycoplasma pneumoniae were not available until nucleic acid amplification methods were developed. The choice of sample type and method of sampling are crucial to optimal diagnostic efficacy. Three types of respiratory samples from 32 young military conscripts with pneumonia were collected during an outbreak of M. pneumoniae infection. Sputum, nasopharyngeal aspirate and throat swab specimens were tested by 16S rRNA gene-based PCR with liquid-phase probe hybridization, and the results were compared with serology. The PCR result was positive for 22 (69 %) of the sputa, 16 (50 %) of the aspirates and 12 (37.5 %) of the swabs. Serology with increasing or high titres supported the positive findings in all instances. Sputum, when available, is clearly the best sample type for young adults with pneumonia.

A sensitive adenovirus immunoassay as a model for using nanoparticle label technology in virus diagnostics

BACKGROUND

Currently, PCR-based hybridization assays are widely applied in adenovirus diagnostics. However, the technology requires tedious sample preparation, and the amplification phase is susceptible to various contaminants leading to inconvenient and time-consuming assay procedure. Methods relying on viral antigen detection, e.g. immunofluorometric assays (IFMAs) and enzyme immunoassays (EIAs), are less complicated to carry out, but they provide limited sensitivity.

OBJECTIVE

Our aim was to develop a simple and sensitive adenovirus assay based on direct antigen detection via sandwich-forming immunoreaction. The assay employed highly fluorescent europium(III)-chelate-doped nanoparticle labels and selection of high affinity monoclonal antibodies (anti-hexon) coated on label particles and microtitration wells.

RESULTS AND CONCLUSIONS

The extremely high specific activity of the nanoparticle labels enabled the detection limit over 5000 virus particles per millilitre with purified virus particles. The sensitivity was improved by three orders of magnitude (800-fold) compared to concurrent time-resolved IFMA. Furthermore, the nanoparticle assay showed reasonably low coefficients of variation (4.0-20%) and excellent linearity of more than four orders of magnitude (from below 10(5) to 10(9) virus particles per millilitre). Analyzed nasopharyngeal patient specimens revealed a minor disturbance of matrix components, which could be avoided by dilution. The average signal difference between negative and positive samples was nearly four orders of magnitude. The developed assay was sensitive and more convenient approach to adenovirus screening compared to available assays. In addition, the study demonstrates the potential of nanoparticles in sensitive screening of viral analytes.

Rapid detection and identification of human adenovirus species by adenoplex, a multiplex PCR-enzyme hybridization assay

Human adenoviruses (AdV) have been implicated in a wide variety of diseases and are ubiquitous in populations worldwide. These agents are of concern particularly in immunocompromised patients, children, and military recruits, resulting in severe disease or death. Clinical diagnosis of AdV is usually achieved through routine viral cell culture, which can take weeks for results. Immunofluorescence and enzyme-linked immunosorbent assay-based techniques are more timely but lack sensitivity. The ability to distinguish between the six different AdV species (A to F) is diagnostically relevant, as infections with specific AdV species are often associated with unique clinical outcomes and epidemiological features. Therefore, we developed a multiplex PCR-enzyme hybridization assay, the Adenoplex, using primers to the fiber gene that can simultaneously detect all six AdV species A through F in a single test. The limit of detection (LOD) based on the viral 50% tissue culture infective dose/ml for AdV A, B, C, D, E, and F was 10(-2), 10(-1), 10(-1), 10(-2), 10(-1), and 10(-2), respectively. Similarly, the LOD for the six DNA controls ranged from 10(2) to 10(3) copies/ml. Twelve common respiratory pathogens were tested with the Adenoplex, and no cross-reactivity was observed. We also validated our assay using clinical specimens spiked with different concentrations of AdV strains of each species type and tested by multiplex PCR and culture. The results demonstrated an overall sensitivity and specificity of Adenoplex of 100%. This assay can be completed in as few as 5 h and provides a rapid, specific, and sensitive method to detect and subtype AdV species A through F.

Development of a PCR-and hybridization-based assay (PCR Adenovirus Consensus) for the detection and the species identification of adenoviruses in respiratory specimens

BACKGROUND

Antigen detection assays and viral isolation techniques are routinely used to detect adenoviruses (Ad) associated with respiratory infections, and the value of the polymerase chain reaction (PCR) has recently been assessed.

OBJECTIVES

This paper describes a PCR-hybridization-immunoenzymatic assay (PCR Adenovirus consensus) used to detect Ad and identify Ad species in respiratory specimens.

RESULTS

On seven representative serotypes Ad 12, Ad 3, Ad 7, Ad 11, Ad 1, Ad 8, Ad 4, the mean genome equivalents per ml and the mean 50% infectious doses per ml were 10(6.3)and 10(4), respectively. Using 362 nasal aspirates from children, Ad were detected by immunofluorescence (IF) and culture in 97 cases (27%), by the PCR-Ad hexon method in 107 cases (29.5%) and by the PCR Adenovirus Consensus method in 113 cases (31.2%); 13 samples were found positive by both PCR and negative by the IF and culture methods; five samples were only positive according to the PCR Adenovirus Consensus) method. The sensitivity, specificity, predictive positive value and predictive negative value of the PCR Adenovirus Consensus method were 97.9%, 93.2%, 84%, 99.1%, respectively. The method identified the species (sp) from 91 positive amplicons: 1 Ad sp A, 44 Ad sp B, 42 Ad sp C, 3 Ad sp E, and 1 Ad sp F; 85 isolates were identified by IF or the neutralisation in culture, and 86 by a PCR-RE digestion method. The PCR Adenovirus Consensus detected six positive samples that were negative according to the IF and culture methods, and it identified the precise species of nine IF-positive and culture-negative nasal aspirates.

CONCLUSION

The PCR Adenovirus Consensus technique is more efficient than the classical IF or culture techniques for the detection of Ad in respiratory samples. An internal control is included to validate the screening results, and specific probes are used to identify the Ad species.

Presence of specific viruses in the middle ear fluids and respiratory secretions of young children with acute otitis media

The purpose of the study was to investigate the presence of different viruses in middle ear fluids and nasopharyngeal aspirates in young children with acute otitis media. Two cohorts of children (N = 329 and 611) were followed from 2 to 24 months of age in Finland in two prospective studies (Finnish Otitis Media Cohort Study and Finnish Otitis Media Vaccine Trial). During the study period, nasopharyngeal and middle ear fluid specimens for each acute otitis media event were examined for eight (Cohort Study) or ten (Vaccine Trial) common respiratory viruses; adenoviruses, influenza viruses A and B, parainfluenza viruses 1, 2, and 3, respiratory syncytial virus (RSV), enteroviruses, parechoviruses, and rhinoviruses. Picornaviruses (rhinoviruses, enteroviruses, and parechoviruses) were determined by reverse transcription PCR while antigen detection was used for the other viruses. A virus was present in either nasopharyngeal or middle ear specimen in 54% of events in the first cohort and in 67% of events in the second. Rhinoviruses formed the most common virus group detected (41–32%), followed by enteroviruses (25%, sought in the second cohort only) and respiratory syncytial virus (RSV) (10%). All the other viruses represented jointly 8–10% of the events. In conclusion, using the methods described in this study, a specific virus infection was diagnosed in two thirds of all acute otitis media events in young children. Picornavirus RNA was detected in association with more than a half of all acute otitis media events. The use of PCR‐based methods for the other respiratory viruses might have increased further the overall virus detection rate in acute otitis media. J. Med. Virol. 72:241–248, 2004. © 2004 Wiley‐Liss, Inc.

Multiplexed, real-time PCR for quantitative detection of human adenovirus

Adenovirus infection is becoming increasingly recognized as a cause of morbidity and mortality in the immunosuppressed patient population. While early detection and quantitation of adenovirus in peripheral blood has been suggested as a means of directing and monitoring antiviral therapy in these patients, few methods have been published, particularly with respect to viral quantitation. A multiplexed real-time PCR assay was developed that can quantitatively detect a wide range of known serotypes of human adenovirus, including all of subgroups A to C. This assay was compared to a qualitative, Southern blot-based PCR assay by using 45 peripheral blood specimens from 16 patients. There was 100% concordance between the two tests in terms of qualitative results. The real-time assay detected adenovirus in patient samples at levels from <200 to 266,681 copies/ml of blood. By using control viral samples, sensitivity was demonstrated to less than 10 copies of viral genome per reaction and quantitative linearity was demonstrated from 10 to 10(6) copies of input viral DNA. Equivalent sensitivity and linearity were demonstrated for 15 different reference serotypes of adenovirus. Eleven other viral serotypes have complete target region sequence homology to one or more of the strains tested. No cross-reactivity was noted with other commonly isolated viral species. Sequence analysis showed no significant homology with any other human pathogens (bacterial or viral). This assay allows rapid, sensitive, and specific quantitation of adenovirus and may have a significant impact on the care of immunocompromised patients at risk for disseminated viral infection.

Viral agents of acute gastroenteritis in German children: prevalence and molecular diversity

Acute gastroenteritis is a major source of morbidity and mortality among young children in developed and developing countries. Enteropathogenic viruses are regarded as particularly relevant causative agents. Between February 2001 and January 2002, fecal specimens were obtained from German children admitted to hospital with acute gastroenteritis and examined for rotaviruses, Noroviruses, enteric adenoviruses, and astroviruses using (RT-)PCR methods. Of the 59% (129/217) samples positive for > or =1 viral agent, 79% (102/129) carried rotavirus, whereas Norovirus was detected in 35% (45/129), enteric adenovirus in 14% (18/129), and astrovirus in 4% (5/129). Thirty-eight specimens contained at least two enteropathogenic viruses, with the majority of coinfections attributable to rotavirus/Norovirus dual infections. Sequence analysis revealed a cocirculation of G1, G3, G4, and G9 type rotavirus with G1 being the most common and G9 the second most common rotavirus G-type. Emergence of G9 rotaviruses in Germany may have implications for future vaccine development. A variety of Norovirus genotypes, most belonging to GGII, were found. Apart from subgenus F, adenovirus related genetically to subgenera A-C were detected. All astroviruses belonged to genotype 1. This is the first study concerning German children admitted to hospital that assesses the relative importance of these viruses by nested (RT-) PCR methods.

Rapid detection of adenovirus in throat swab specimens by PCR during respiratory disease outbreaks among military recruits

We evaluated the performance of a generic PCR test to detect adenoviruses (AdV) in throat swab specimens collected from asymptomatic and ill military recruits with acute respiratory disease. Samples (n = 210) were collected at entry to basic training and at the time of large outbreaks of AdV-associated acute respiratory disease among military recruits at Fort Jackson, South Carolina, from 1997 to 1998. Compared to cell culture, a sensitivity of 99% and a specificity of 98% were noted for the PCR method to detect AdV in throat swabs. Similar results were obtained with or without DNA extraction, suggesting the absence of significant inhibitors for the PCR method in throat swab samples. No AdV was detected by culture or PCR in throat swabs from healthy recruits, suggesting the absence of latency or asymptomatic shedding. Throat swab specimens proved to be adequate, noninvasive samples to rapidly diagnose respiratory disease in young adults. This generic direct PCR proved to be a useful test for the rapid diagnosis of AdV-associated respiratory disease, detecting all serotypes tested to date and furnishing results within 6 h of specimen arrival. The use of this direct, rapid, sensitive, and specific assay would assist health care providers and public health practitioners in the early diagnosis, management, and control of AdV-associated respiratory disease.

Adenovirus infection in pediatric liver and intestinal transplant recipients: utility of DNA detection by PCR

To evaluate the incidence of adenovirus (AdV) infection in pediatric liver and intestinal transplant recipients, the records of patients with possible AdV infection were reviewed for demographic data, symptomatology, methods of diagnosis, treatment and outcome. To evaluate the impact of polymerase chain reaction (PCR) amplification and identification of AdV DNA as a diagnostic test, the incidence and outcome of AdV before and after the introduction of PCR were compared. Adenovirus infection was identified in 4.1% of liver recipients and 20.8% of intestinal transplant recipients. The overall incidence of AdV did not increase over time, even following the introduction of PCR for virus detection. The higher incidence of AdV in the pediatric intestinal transplant recipients may be attributed to the frequent application of PCR methodology to intestinal biopsy material. Detection of AdV by PCR was associated with reduced mortality compared with detection by culture, either because of earlier detection of invasive disease or because PCR detects the presence of latent as well as active AdV.

Intravenous ribavirin treatment for severe adenovirus disease in immunocompromised children

BACKGROUND

Adenovirus is an important cause of morbidity and mortality in the immunocompromised host. The incidence of severe adenovirus disease in pediatrics is increasing in association with growing numbers of immunocompromised children, where case fatality rates as high as 50% to 80% have been reported. There are no approved antiviral agents with proven efficacy for the treatment of severe adenovirus disease, nor are there any prospective randomized, controlled trials of potentially useful anti-adenovirus therapies. Apparent clinical success in the treatment of severe adenovirus disease is limited to a few case reports and small series. Experience is greatest with intravenous ribavirin and cidofovir. Ribavirin, a guanosine analogue, has broad antiviral activity against both RNA and DNA viruses, including documented activity against adenovirus in vitro. Ribavirin is licensed in aerosol form for the treatment of respiratory syncytial virus infection, and orally in combination with interferon to treat hepatitis C. Intravenous ribavirin is the treatment of choice for infection with hemorrhagic fever viruses. The most common adverse effect of intravenous ribavirin is reversible mild anemia. The use of cidofovir in severe adenovirus infection has been limited by adverse effects, the most significant of which is nephrotoxicity.

OBJECTIVE

We report our experience with intravenous ribavirin therapy for severe adenovirus disease in a series of immunocompromised children and review the literature.

DESIGN/METHODS

We retrospectively reviewed the medical records of 5 children treated with intravenous ribavirin for documented severe adenovirus disease. Two patients developed adenovirus hemorrhagic cystitis after cardiac and bone marrow transplants, respectively. The bone marrow transplant patient also received intravenous cidofovir for progressive disseminated disease. An additional 3 children developed adenovirus pneumonia; 2 were neonates, 1 of whom had partial DiGeorge syndrome. The remaining infant had recently undergone a cardiac transplant. Intravenous ribavirin was administered on a compassionate-use protocol.

RESULTS

Complete clinical recovery followed later by viral clearance was observed in 2 children: the cardiac transplant recipient with adenovirus hemorrhagic cystitis and the immunocompetent neonate with adenovirus pneumonia. The remaining 3 children died of adenovirus disease. Intravenous ribavirin therapy was well tolerated. Use of cidofovir in 1 child was associated with progressive renal failure and neutropenia.

DISCUSSION

Our series of patients is representative of the spectrum of immunocompromised children at greatest risk for severe adenovirus disease, namely solid-organ and bone marrow transplant recipients, neonates, and children with immunodeficiency. Although intravenous ribavirin was not effective for all children with severe adenovirus disease in this series or in the literature, therapy is unlikely to be of benefit if begun late in the course of the infection. Early identification, eg by polymerase chain reaction of those patients at risk of disseminated adenovirus disease may permit earlier antiviral treatment and better evaluation of therapeutic response.

CONCLUSIONS

Two of 5 children with severe adenovirus disease treated with intravenous ribavirin recovered. The availability of newer rapid diagnostic techniques, such as polymerase chain reaction, may make earlier, more effective treatment of adenovirus infection possible. Given the seriousness and increasing prevalence of adenovirus disease in certain hosts, especially children, a large, multicenter clinical trial of potentially useful anti-adenoviral therapies, such as intravenous ribavirin, is clearly required to demonstrate the most effective and least toxic therapy.

Evaluation of the role of respiratory viruses in acute myringitis in children less than two years of age

BACKGROUND

The etiology of acute myringitis remains controversial although it is usually encountered in connection with acute otitis media (AOM). In most cases of acute myringitis a bacterial pathogen has been detected in the middle ear fluid, but the role of respiratory viruses has remained unclear. Our objective was to investigate the etiologic role of viruses in the pathogenesis of acute bullous and hemorrhagic myringitis in children <2 years of age.

METHODS

A prospective longitudinal cohort study of 2028 children ages 7 to 24 months in primary care in the Finnish Otitis Media Vaccine Trial. Nasopharyngeal aspirate (NPA) and middle ear fluid (MEF) samples taken at the time of the diagnosis were examined by a time-resolved fluoroimmunoassay for antigen detection of adenoviruses; influenza viruses A and B; parainfluenza viruses 1, 2 and 3; and respiratory syncytial virus and by reverse transcription polymerase chain reaction for human rhinovirus and human enterovirus.

RESULTS

Eighty-two children with bullous myringitis and 37 children with hemorrhagic myringitis were diagnosed during the 18-month follow-up period. In bullous myringitis a respiratory virus was detected in 70% of NPA samples and in 27% of MEF samples. In hemorrhagic myringitis 57% of NPA samples and 28% of MEF samples were virus-positive. The viral distribution was similar to that of AOM (virus positive 64% of NPA and 37% of MEF).

CONCLUSIONS

We could not confirm any specific respiratory virus to be the etiologic agent in acute myringitis. The etiology of acute myringitis is similar to that of AOM in children <2 years of age.

Rapid type-specific diagnosis of adenovirus type 4 infection using a hexon-based quantitative fluorogenic PCR

A hexon-based fluorogenic polymerase chain reaction (PCR) assay utilizing the 5'-nuclease activity of DNA Taqpolymerase was developed as a rapid and type-specific diagnostic system for adenovirus type 4 (Ad4) detection and quantification. The assay consists of a pair of flanking primers and an internal fluorescence labeled probe that allows real time amplification to quantify the Ad4 virus. One out of 12 flanking primer pairs evaluated (combinations of three forward primers and four reverse primers) was found to be optimal for Ad4 virus detection that yielded background-free operation, i.e., no fluorescent signal generated by non-template controls. The assay was employed to detect Ad4 reference virus strain RI-67, Wyeth Ad4 vaccine strain and 71 different clinical Ad4 isolates from US military recruits used in this study with consistent sensitivity (lower detection limit) of 2-4 pfu per PCR reaction. The assay showed linear Ad4 detection with a dynamic range of greater than five logs (from 2-4 pfu/assay to greater than 10(5) pfu/assay). This Ad4-specific assay did not crossreact with representative members of Ad subgroups A, B, C, D and F at viral concentrations greater than 10(8) pfu/ml. It was also demonstrated that Ad4 viruses could be efficiently detected from throat swabs (71/72 specimens or 98.6% detection sensitivity) of infected patients by the Ad4-specific PCR. In general, there was a good correlation between PCR determined viral titers in throat swabs and time required to detect viral cytopathic effects (CPE) in cell culture. Evaluation of the simple Ad4 specific assay developed in this study could be used to provide a rapid clinically relevant diagnosis of Ad4 infections in patients with acute respiratory disease (ARD).

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

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

Respiratory viruses, symptoms, and inflammatory markers in acute exacerbations and stable chronic obstructive pulmonary disease

The effects of respiratory viral infection on the time course of chronic obstructive pulmonary disease (COPD) exacerbation were examined by monitoring changes in systemic inflammatory markers in stable COPD and at exacerbation. Eighty-three patients with COPD (mean [SD] age, 66.6 [7.1] yr, FEV(1), 1.06 [0.61] L) recorded daily peak expiratory flow rate and any increases in respiratory symptoms. Nasal samples and blood were taken for respiratory virus detection by culture, polymerase chain reaction, and serology, and plasma fibrinogen and serum interleukin-6 (IL-6) were determined at stable baseline and exacerbation. Sixty-four percent of exacerbations were associated with a cold occurring up to 18 d before exacerbation. Seventy-seven viruses (39 [58.2%] rhinoviruses) were detected in 66 (39.2%) of 168 COPD exacerbations in 53 (64%) patients. Viral exacerbations were associated with frequent exacerbators, colds with increased dyspnea, a higher total symptom count at presentation, a longer median symptom recovery period of 13 d, and a tendency toward higher plasma fibrinogen and serum IL-6 levels. Non-respiratory syncytial virus (RSV) respiratory viruses were detected in 11 (16%), and RSV in 16 (23.5%), of 68 stable COPD patients, with RSV detection associated with higher inflammatory marker levels. Respiratory virus infections are associated with more severe and frequent exacerbations, and may cause chronic infection in COPD. Prevention and early treatment of viral infections may lead to a decreased exacerbation frequency and morbidity associated with COPD.

Epidemiology of documented viral respiratory infections and acute otitis media in a cohort of children followed from two to twenty-four months of age

BACKGROUND

Viral upper respiratory infections (URIs) are considered major risk factors for acute otitis media (AOM) in young children. We studied the epidemiology and relative roles of different viruses in respiratory infections in a cohort of 329 Finnish children followed from 2 months to 2 years of age.

METHODS

A nasopharyngeal aspirate (NPA) was collected whenever the child had signs and/or symptoms of URI and tested for the presence of common respiratory virus antigens or infectivity/nucleic acid (only rhinoviruses). Possible repeated detections of a given virus during a 30-day period were considered to represent a single designated virus-specific episode. AOM and URI episodes were defined in a similar way.

RESULTS

At least one virus was detected in 837 (41.7%) of the 2005 NPA specimens examined. Rates of URI and virus-specific episodes showed expected seasonal variation with major peak occurrences coinciding with or preceding those of AOM. The proportions of rhinoviruses, respiratory syncytial (RS) virus, parainfluenza virus (PIV) type 3, influenza virus A and adenoviruses were 63.1, 14.7, 6.7, 6.7 and 6.2% of the total of 761 virus-specific episodes. Influenza virus B, PIV1 and PIV2 were each responsible for approximately 1% of the episodes. AOM was diagnosed in 870 URI cases (43.4%) and in 43.3% of cases associated with a virus-positive NPA. The latter figure was clearly higher (57.7%) for RS virus-positive specimens.

CONCLUSIONS

The seasonal coincidence of URI and AOM demonstrated the obvious role of URI in the pathogenesis of AOM. The occurrence of rhinoviruses and RS virus in URI was strikingly more common than that of any other virus tested. Although rhinoviruses were definitely the most frequently found viruses in NPA specimens, the association of RS virus with concurrent AOM was relatively higher than that of any other virus.

Acceptable protective efficacy of influenza vaccination in young military conscripts under circumstances of incomplete antigenic and genetic match

Commercial inactivated parenteral influenza vaccines reduced febrile (> or = 38 degrees C) respiratory illness by 53% (95% CL: 41-63%) during a 3 week outbreak in 1998 when A/Sydney/5/97(H3N2)-like influenza viruses were shown to be the predominant etiological agents and an older antigenic variant, A/Nanchang/933/95, served as the vaccine virus. The calculatory efficacy for preventing virologically diagnosed influenza infections was 57% (95% CL: 40-68%). The study population consisted of 1374 young male military conscripts. Vaccination coverage on a voluntary basis was 67%. Vaccination was ineffective in preventing febrile illness during a second epidemic wave lasting 2 weeks when mainly adenoviruses were shown to have been circulating in the garrison. Out of the 36 nasopharyngeal aspirates positive for influenza A by antigen detection, 18 A/Sydney/5/97-like strains (10 from non-vaccinated and eight from vaccinated subjects) and two A/Nanchang/933/95-like strains (both from non-vaccinated subjects) were isolated in MDCK cell cultures. Intraepidemic variation was detected among the A/Sydney/5/97-like field strains in their HA1 sequences and reactivity in HI tests, but no evidence was obtained that this variation would have been of significance to the virus in breaking through the vaccination-induced immunity.

Rapid and sensitive diagnosis of human adenovirus infections by a generic polymerase chain reaction

A new adenovirus specific nested polymerase chain reaction (PCR) method is described. It was designed inside the hexon protein gene of the adenovirus genome, and was able to detect DNA of all 47 human adenovirus types in a wide range of clinical samples. A sensitive internal control system able to assure proper analytical conditions for the amplification of as few as 100 molecules of a heterologous DNA was included to avoid false negative results. Sensitivity was estimated at about 10 molecules per tube of a plasmid containing an insert of the first amplification product. The method was able to detect adenovirus infection in 31/43 conjunctival scrapings from patients with acute kerato conjunctivitis 10/40 nasopharyngeal aspirates from patients admitted to hospital with acute respiratory disease and 2/26 urine samples from patients with haemorrhagic cystitis with better sensitivity than cell culture or rapid diagnosis by antigen detection by immunofluorescence (IF) in the case of respiratory specimens. Only two of 17 stools positive for a group F adenovirus specific latex immunoassay were PCR negative. The internal control system avoided a false negative result on another two stool samples. In conclusion, the method described below was shown to be useful for rapid diagnosis of adenovirus infections with higher sensitivity than antigen detection by IF.

Adenovirus infections in adult recipients of blood and marrow transplants

Adenoviruses are increasingly recognized pathogens that affect blood and marrow transplant (BMT) recipients. Experiences with 2889 adult BMT recipients were reviewed to study the incidence, clinical spectrum, risk factors for dissemination, response to therapy, and outcome of adenovirus infections. Eight-five patients (3%) were diagnosed by means of culture (n=85) or culture and histopathological examination (n=6). Nine patients had asymptomatic viruria, and 76 had symptomatic infections, which included upper respiratory tract infection (n=20), enteritis (n=18), hemorrhagic cystitis (n=10), pneumonia (n=15), and disseminated disease (n=13). The overall mortality rate was 26%. A higher mortality rate was observed among patients with pneumonia (73%) and disseminated disease (61%). Risk factors for dissemination included receipt of an allogeneic transplant, presence of graft-versus-host disease (GVHD), and receipt of concurrent immunosuppressive therapy. Intravenous ribavirin was not associated with an appreciable benefit among 12 patients who received this treatment. In conclusion, adenovirus infections are an important cause of morbidity and mortality in adult BMT recipients, particularly allogeneic transplant recipients with GVHD who are receiving immunosuppressive therapy. The need for an effective, nontoxic antiviral therapy is apparent.

Species-specific identification of human adenoviruses by a multiplex PCR assay

A multiplex PCR assay was developed by using primers to the fiber gene that could differentiate human adenovirus (Ad) species A through F in a single amplification reaction. The assay correctly identified the species of all 49 recognized Ad prototype strains as well as 180 geographically and temporally diverse Ad field isolates. Ad serotype 6 (Ad6) (species C), Ad16 (species B), Ad31 (species A), and Ad40 and Ad41 (species F) could also be distinguished by amplicon size within each respective species. In comparison, a previously described Ad species-specific multiplex PCR assay that used primers to the Ad hexon gene gave equivocal results with several serotypes of species B, whereas our multiplex assay amplified all species B serotypes equally well. Our multiplex PCR assay will permit rapid, accurate, and cost-effective classification of Ad isolates.