Infections in 18,000 infants and children in a controlled study of respiratory tract disease. I. Adenovirus pathogenicity in relation to serologic type and illness syndrome

Proportion of Respiratory Syncytial Virus, SARS-CoV-2, Influenza A/B, and Adenovirus Cases via Rapid Tests in the Community during Winter 2023-A Cross Sectional Study

Respiratory infections constitute a major reason for infants and children seeking medical advice and visiting health facilities, thus remaining a significant public threat with high morbidity and mortality. The predominant viruses causing viral respiratory infections are influenza A and B viruses (Flu-A, Flu-B), respiratory syncytial virus (RSV), adenovirus and coronaviruses. We aimed to record the proportion of RSV, SARS-CoV-2, influenza A/B and adenovirus cases with rapid antigen tests and validate the results with RT-PCR assays of upper respiratory specimens with a wide range of viral loads and (co)-infection patterns in children. Clinical samples were collected from early symptomatic children (presenting with fever and/or cough and/or headache within 5-7 days). The surveillance program was conducted in five private pediatric dispensaries and one pediatric care unit, from 10 January 2023 to 30 March 2023 in central Greece. The total sample of specimens collected was 784 young children and infants, of which 383 (48.8%) were female and 401 were male (51.2%). The mean age of participants was 7.3 + 5.5 years. The sensitivity of the FLU A & B test was 91.15% (95% CI: 84.33-95.67%), and the specificity was 98.96% (95% CI: 97.86-99.58%). The sensitivity and specificity of the adenovirus and RSV test was {92.45% (95% CI: 81.79-97.91%), 99.32% (95% CI: 98.41-99.78%)} and {92.59% (95% CI: 75.71-99.09%), 99.47% (95% CI: 98.65-99.86%)} respectively. Lastly, the sensitivity of the SARS-CoV-2 test was 100.00% (95% CI: 79.41-100.00%) and the specificity was 99.74% (95% CI: 99.06-99.97%). We recorded a proportion of 14.3% and 3.44% for influenza A and B, respectively, followed by a proportion of 6.9% for adenovirus, a proportion of 3.7% for RSV, and finally, a proportion of 2.3% for SARS-CoV-2. The combination of a new multiple rapid test with multiple antigens will probably be a useful tool with a financial impact for health systems targeting the early detection and appropriate treatment of respiratory infections in emergency departments in primary health care facilities.

Human Adenovirus Infection Causing Hyperinflammatory Syndrome Mimicking Multisystem Inflammatory Syndrome in Children (MIS-C): A Case Report

Transmission of human adenovirus (HAdV) infection and the associated clinical disease can be sporadic or epidemic and manifestations may range from mild infection to severe disease. HAdV has been seen to behave as a proinflammatory virus that can trigger the release of high levels of inflammatory cytokines and chemokines in children. Here, we report an unusual case of an infant with HAdV infection who presented with respiratory illness, with a protracted course, complicated with hyperinflammation and multi-system involvement with clinical characteristics mimicking multisystem inflammatory syndrome in children (MIS-C) and Kawasaki disease. The patient was an 11-month-old male infant with a background of infantile epilepsy, epileptic encephalopathy, hemimegaloencephaly, and global developmental delay, diagnosed as Ohtahara syndrome. He was admitted with a three-day history of cough, cold, fever, and respiratory distress. Management was initiated with a heated humidified high-flow nasal cannula and given ceftriaxone and hypertonic saline nebulization. Additionally, he developed loose motion on the fifth day of admission. The reverse transcriptase polymerase chain reaction (RT-PCR) of the nasopharyngeal swab was positive for HAdV. Due to persistent fever, elevated inflammatory markers, multisystem involvement (diarrhea, coagulopathy), an absence of a clear microbial etiology, and an epidemiologic link to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, MIS-C was diagnosed. The first dose of intravenous immunoglobulins (IVIG) was administered over the course of 48 hours and the baby required a second dose of IVIG as the fever failed to settle after the first dose. Within 24 hours of the second IVIG dose, defervescence occurred. His platelet count started to rise, and the baby developed thrombocytosis in the third week of illness. Echocardiography was suggestive of dilatation of mild left main coronary artery. He was weaned off oxygen support by day 14 and discharged on day 17. To our knowledge, this is the first reported case of HAdV infection with hyperinflammatory syndrome and vasculitis akin to MIS-C and Kawasaki disease.

Multi-omic interactions in the gut of children at the onset of islet autoimmunity

BACKGROUND

The gastrointestinal ecosystem is a highly complex environment with a profound influence on human health. Inflammation in the gut, linked to an altered gut microbiome, has been associated with the development of multiple human conditions including type 1 diabetes (T1D). Viruses infecting the gastrointestinal tract, especially enteroviruses, are also thought to play an important role in T1D pathogenesis possibly via overlapping mechanisms. However, it is not known whether the microbiome and virome act together or which risk factor may be of greater importance at the time when islet autoimmunity is initiated.

RESULTS

Here, we apply an integrative approach to combine comprehensive fecal virome, microbiome, and metaproteome data sampled before and at the onset of islet autoimmunity in 40 children at increased risk of T1D. We show strong age-related effects, with microbial and metaproteome diversity increasing with age while host antibody number and abundance declined with age. Mastadenovirus, which has been associated with a reduced risk of T1D, was associated with profound changes in the metaproteome indicating a functional shift in the microbiota. Multi-omic factor analysis modeling revealed a cluster of proteins associated with carbohydrate transport from the genus Faecalibacterium were associated with islet autoimmunity.

CONCLUSIONS

These findings demonstrate the interrelatedness of the gut microbiota, metaproteome and virome in young children. We show a functional remodeling of the gut microbiota accompanies both islet autoimmunity and viral infection with a switch in function in Faecalibacterium occurring at the onset of islet autoimmunity. Video Abstract.

Human adenovirus infections in pediatric population - an update on clinico-pathologic correlation

Human adenoviruses can cause infections at any age but most commonly in pediatric population, especially in young children and infants. By the time of 10 years old, most children have had at least one episode of adenovirus infection. Adenoviruses can cause many symptoms similar to common cold, including rhinorrhea, fever, cough, and sore throat. Lower respiratory infections such as bronchitis, bronchiolitis, and pneumonia can be severe and even fatal. Other diseases such as conjunctivitis, gastroenteritis, cystitis, myocarditis, cardiomyopathy, and meningoencephalitis can also be associated with adenovirus infections. A variety of recent advancement of structural and molecular biology methods have revamped the taxonomy of adenoviruses and furthered our understanding of the diversity of related clinical diseases. Because of the wide spectrum and complexity of diseases associated with human adenovirus infections, the scope of this review is limited to basic virology and epidemiology of adenoviruses with a main focus on the clinico–pathologic correlation. Clinical manifestations and pathology of any infectious disease are always related; therefore, it is logical to review clinico–pathologic correlation within the specific disease entity caused by adenoviruses to better understand this common viral infection in pediatric population.

Lactoferrin-Hexon Interactions Mediate CAR-Independent Adenovirus Infection of Human Respiratory Cells

Many viruses enter target cells using cell adhesion molecules as receptors. Paradoxically, these molecules are abundant on the lateral and basolateral side of intact, polarized, epithelial target cells, but absent on the apical side that must be penetrated by incoming viruses to initiate infection. Our study provides a model whereby viruses use different mechanisms to infect polarized epithelial cells depending on which side of the cell—apical or lateral/basolateral—is attacked. This study may also be useful to understand the biology of other viruses that use cell adhesion molecules as receptors.

Virus entry into host cells is a complex process that is largely regulated by access to specific cellular receptors. Human adenoviruses (HAdVs) and many other viruses use cell adhesion molecules such as the coxsackievirus and adenovirus receptor (CAR) for attachment to and entry into target cells. These molecules are rarely expressed on the apical side of polarized epithelial cells, which raises the question of how adenoviruses—and other viruses that engage cell adhesion molecules—enter polarized cells from the apical side to initiate infection. We have previously shown that species C HAdVs utilize lactoferrin—a common innate immune component secreted to respiratory mucosa—for infection via unknown mechanisms. Using a series of biochemical, cellular, and molecular biology approaches, we mapped this effect to the proteolytically cleavable, positively charged, N-terminal 49 residues of human lactoferrin (hLF) known as human lactoferricin (hLfcin). Lactoferricin (Lfcin) binds to the hexon protein on the viral capsid and anchors the virus to an unknown receptor structure of target cells, resulting in infection. These findings suggest that HAdVs use distinct cell entry mechanisms at different stages of infection. To initiate infection, entry is likely to occur at the apical side of polarized epithelial cells, largely by means of hLF and hLfcin bridging HAdV capsids via hexons to as-yet-unknown receptors; when infection is established, progeny virions released from the basolateral side enter neighboring cells by means of hLF/hLfcin and CAR in parallel.

IMPORTANCE Many viruses enter target cells using cell adhesion molecules as receptors. Paradoxically, these molecules are abundant on the lateral and basolateral side of intact, polarized, epithelial target cells, but absent on the apical side that must be penetrated by incoming viruses to initiate infection. Our study provides a model whereby viruses use different mechanisms to infect polarized epithelial cells depending on which side of the cell—apical or lateral/basolateral—is attacked. This study may also be useful to understand the biology of other viruses that use cell adhesion molecules as receptors.

Mating strategy is determinant of adenovirus prevalence in European bats

Adenoviruses are double-strained DNA viruses found in a great number of vertebrates, including humans. In order to understand their transmission dynamics, it is crucial, even from a human health perspective, to investigate how host traits influence their prevalence. Bats are important reservoirs for adenoviruses, and here we use the results of recent screenings in Western Europe to evaluate the association between characteristic traits of bat species and their probability of hosting adenoviruses, taking into account their phylogenetic relationships. Across species, we found an important phylogenetic component in the presence of adenoviruses and mating strategy as the most determinant factor conditioning the prevalence of adenoviruses across bat species. Contrary to other more stable mating strategies (e.g. harems), swarming could hinder transmission of adenoviruses since this strategy implies that contacts between individuals are too short. Alternatively, bat species with more promiscuous behavior may develop a stronger immune system. Outstandingly high prevalence of adenoviruses was reported for the Iberian species Pipistrellus pygmaeus, P. kuhlii and Nyctalus lasiopterus and we found that in the latter, males were more likely to be infected by adenoviruses than females, due to the immunosuppressing consequence of testosterone during the mating season. As a general trend across species, we found that the number of adenoviruses positive individuals was different across localities and that the difference in prevalence between populations was correlated with their geographic distances for two of the three studied bat species (P. pygmaeus and P.kuhlii). These results increase our knowledge about the transmission mechanisms of adenoviruses.

Severe Adenovirus Pneumonia Requiring Extracorporeal Membrane Oxygenation Support in Immunocompetent Children

Objective: To highlight severe adenovirus pneumonia in immunocompetent patients by analysis of severe adenovirus pneumonia associated with acute respiratory distress syndrome in whom extracorporeal membrane oxygenation (ECMO) support is required. Methods:Pediatric patients with adenovirus pneumonia and ECMO supports in our hospital from February 2018 to May 2019 were retrospectively analyzed, and having 100 common adenovirus pneumonia children as a control. Results:A total of 8 patients, including 4 boys (50.0%), were enrolled. They were previously immunocompetent with a median age of 31 months. They were admitted as persistent fever and cough for more than one week. Median time prior to development of respiratory failure requiring intubation and invasive mechanical ventilation was 5 days. Venoarterial ECMO support as rescue ventilation was instituted after a median time of 24.5 h of conventional mechanical ventilator support. The median duration on ECMO support was 9 days and mechanical ventilation was 14 days, respectively. Six patients (75%) were recovered and 2 (25%) died. Median length of stay in ICU and hospital were 27.5 days and 47.5 days, respectively. Conclusion:The promising outcomes of our cases suggested that ECMO support for rescue ventilation may be considered when symptoms deteriorated in adenovirus pneumonia patients, and may improve outcome. However, sequelae of adenovirus pneumonia and ECMO-related complications should also be taken into account.

Infectious Lung Disease

Infectious diseases are one of the main causes of morbidity and mortality worldwide. With new pathogens continuously emerging, known infectious diseases reemerging, increasing microbial resistance to antimicrobial agents, global environmental change, ease of world travel, and an increasing immunosuppressed population, recognition of infectious diseases plays an ever-important role in surgical pathology. This becomes particularly significant in cases where infectious disease is not suspected clinically and the initial diagnostic workup fails to include samples for culture. As such, it is not uncommon that a lung biopsy becomes the only material available in the diagnostic process of an infectious disease. Once the infectious nature of the pathological process is established, careful search for the causative agent is advised. This can often be achieved by examination of the hematoxylin and eosin-stained sections alone as many organisms or their cytopathic effects are visible on routine staining. However, ancillary studies such as histochemical stains, immunohistochemistry, in situ hybridization, or molecular techniques may be needed to identify the organism in tissue sections or for further characterization, such as speciation.

[Research progress on early identification of severe adenovirus pneumonia in children]

Severe adenovirus pneumonia has a high mortality and incidence of sequelae. Fever and cough are the main symptoms of children's severe adenovirus pneumonia, but such clinical manifestations are lack of specificity. For children with persistent high fever who are in the epidemic age and season, the adenovirus etiology detection, blood routine, cytokines, T cell subsets and imaging examinations are suggested. Children with early manifestations of infiltration of lung segment and lobar parenchyma, obvious emphysema, interstitial pneumonia or a large amount of pleural effusion should be alerted to have severe adenovirus pneumonia. This article reviews the epidemiological characteristics and risk factors of adenovirus pneumonia in different seasons, regions and serology, and the laboratory findings and imaging features of severe adenovirus pneumonia, which would be helpful for the early identification of the disease.

Genetic diversity and quantification of human mastadenoviruses in wastewater from Sydney and Melbourne, Australia

Human mastadenoviruses (HAdVs) are DNA viruses that can cause a wide range of clinical diseases, including gastroenteritis, respiratory illnesses, conjunctivitis, and in more severe cases hepatitis, pancreatitis and disseminated diseases. HAdV infections are generally asymptomatic or self-limiting, but can cause adverse outcomes within vulnerable populations. Since most HAdV serotypes replicate within the human gastrointestinal tract, high levels of HAdV DNA are excreted into wastewater systems. In this study, we identified the genetic diversity of HAdV at a population level using wastewater samples collected from Sydney and Melbourne from 2016 to 2017, with the use of next generation sequencing (NGS) technologies. In addition, HAdV DNA levels were quantified using quantitative polymerase chain reaction (qPCR) based methods to better understand the health risks involved if wastewater contamination occurs. An average of 1.8 × 10⁷ genome copies of HAdV DNA was detected in one litre of wastewater collected in Sydney and Melbourne, over the two-year study period. A total of six major groups of HAdV were identified in wastewater samples using MiSeq, which included 19 different serotypes. Of those, the most prevalent was F41 (83.5%), followed by F40 (11.0%) and A31 (3.7%). In contrast, five groups of HAdV were identified in clinical samples with F41 as the most dominant serotype, (52.5% of gastroenteritis cases), followed by C1 and C2 (each responsible for 15.0%), and B3 was the fourth most common serotype (7.5%). This study demonstrated the practicability of using amplicon based NGS to identify HAdV diversity and quantify HAdV genome levels in environmental water samples, as well as broadening our current understanding of circulating HAdV in the Australian population.

QMRA of adenovirus in drinking water at a drinking water treatment plant using UV and chlorine dioxide disinfection

According to the Dutch Drinking Water Act of 2011, Dutch drinking water suppliers must conduct a Quantitative Microbial Risk Assessment (QMRA) for infection by the following index pathogens: enterovirus, Campylobacter, Cryptosporidium and Giardia at least once every four years in order to assess the microbial safety of drinking water. The health-based target for safe drinking water is set at less than one infection per 10 000 persons per year. At Evides Water Company, concern has arisen whether their drinking water treatment, mainly based on UV inactivation and chlorine dioxide, reduces levels of adenovirus (AdV) sufficiently. The main objective was, therefore, to conduct a QMRA for AdV. Estimates of the AdV concentrations in source water were based on enumeration of total AdV by integrated cell culture PCR (iccPCR), most probable number PCR (mpnPCR) and quantitative PCR (qPCR), and on enumeration of AdV40/41 by mpnPCR and qPCR. AdV40/41 represents a large fraction of total AdV and only a small fraction of AdV is infectious (1/1700). By comparison of literature data and plant scale data, somatic coliphages appeared a good, conservative indicator for AdV disinfection by UV irradiation. Similarly, bacteriophage MS2 appeared to be a good, conservative indicator for disinfection by chlorine dioxide. Literature data on the efficiency of chlorine dioxide disinfection were fitted with the extended HOM model. Chlorine dioxide disinfection at low initial concentrations (0.05-0.1 mg/l) was found to be the major treatment step, providing sufficient treatment on its own for compliance with the health-based target. UV disinfection of AdV at 40 mJ/cm² or 73 mJ/cm² was insufficient without chlorine dioxide disinfection.

A review of 65 years of human adenovirus seroprevalence

Introduction: Human adenovirus (HAdV)-derived vectors have been used in numerous pre-clinical and clinical trials during the last 40 years. Current research in HAdV-based vaccines focuses on improving transgene immunogenicity and safety. Because pre-existing humoral immunity against HAdV types correlate with reduced vaccine efficacy and safety, many groups are exploring the development of HAdV types vectors with lower seroprevalence. However, global seroepidemiological data are incomplete. Areas covered: The goal of this review is to centralize 65 years of research on (primarily) HAdV epidemiology. After briefly addressing adenovirus biology, we chronical HAdV seroprevalence studies and highlight major milestones. Finally, we analyze data from about 50 studies with respect to HAdVs types that are currently used in the clinic, or are in the developmental pipeline. Expert opinion: Vaccination is among the most efficient tools to prevent infectious disease. HAdV-based vaccines have undeniable potential, but optimization is needed and antivector immunity remains a challenge if the same vectors are to be administrated to different populations. Here, we identify gaps in our knowledge and the need for updated worldwide epidemiological data.

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

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

Human adenovirus in nasopharyngeal and blood samples from children with and without respiratory tract infections

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Positive HAdV culture and high levels of HAdV DNA >10⁶ copies/mL in NPAs were strongly associated with RTI in hospitalized children.

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Co-detection of other viruses was a very common phenomenon in children with HAdV DNA positive NPAs.

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Qualitative PCR detection of HAdV DNA in NPAs was not useful for diagnostic purposes.

Background

Human adenovirus (HAdV) is a double-stranded DNA virus associated with respiratory tract infections (RTI) in children. Using polymerase chain reaction (PCR) tests, HAdV often is detected together with other virus species, even in healthy controls.

Objectives

The aim of this study was to compare molecular detection of HAdV with culture, and to examine the associations of various methods to RTI.

Study design

Nasopharyngeal aspirates (NPA) were collected from 4319 children admitted with RTI and from 361 controls. The NPAs were examined for 23 viral and bacterial pathogens, using inhouse real-time PCR-assays based on TaqMan probes, in addition to bacterial and viral culture. HAdV concentration was evaluated semi-quantitatively from the Ct-value and quantitatively by use of ADENOVIRUS R-gene®.

Results

HAdV-DNA was detected in 6.1% patient samples and in 10.5% controls (p< 0.001). Compared to controls, patients had an OR of 3.8 (95% CI 1.4–10.3) for mono-detection of HAdV DNA, and an OR of 5.1 (95% CI 2.0–13.4) for HAdV-positive samples grew adenovirus by culture. HAdV DNA loads from children with RTI consisted of two clusters: one cluster with high viral loads (Ct < 30 and >106 copies/ml) and one cluster with low viral loads, whereas among the controls, nearly all had low viral loads (OR 7.8, 95% CI 2.2–27.1). In 61 available plasma samples, 16.4% were positive for HAdV DNA, all were from patients.

Conclusion

The detection of HAdV DNA per se by qualitative PCR is not useful as a diagnostic test. Detection of HAdV by use of viral culture and a high viral HAdV DNA load are the two methods most strongly associated with RTI in children.

Simulation of four respiratory viruses and inference of epidemiological parameters

While influenza has been simulated extensively to better understand its behavior and predict future outbreaks, most other respiratory viruses have seldom been simulated. In this study, we provide an overview of four common respiratory viral infections: respiratory syncytial virus (RSV), respiratory adenovirus, rhinovirus and parainfluenza, present specimen data collected 2004–2014, and simulate outbreaks in 19 overlapping regions in the United States. Pairing a compartmental model and data assimilation methods, we infer key epidemiological parameters governing transmission: the basic reproductive number R₀ and length of infection D. RSV had been previously simulated, and our mean estimate of D and R₀ of 5.2 days and 2.8, respectively, are within published clinical and modeling estimates. Among the four virus groupings, mean estimates of R₀ range from 2.3 to 3.0, with a lower and upper quartile range of 2.0–2.8 and 2.6–3.2, respectively. As rapid PCR testing becomes more common, estimates of the observed virulence and duration of infection for these viruses could inform decision making by clinicians and officials for managing patient treatment and response.

The role of the NxTAG® respiratory pathogen panel assay and other multiplex platforms in clinical practice

INTRODUCTION

The advent of nucleic acid amplification tests has significantly improved the aetiologic diagnosis of respiratory infections. However, multiplex real-time polymerase chain reaction (PCR) can be technologically challenging. Areas covered: This paper reports the results of the main published studies on the NxTAG Respiratory Pathogen Panel (RPP) and discusses the advantages and disadvantages of extensive use of multiplex assays in clinical practice. Expert commentary: Currently available data seem to indicate that routine use of multiplex assays, including NxTAG RPP Assay, should be recommended only when epidemiological data concerning circulation of viruses and bacteria have to be collected. Their use in clinical practice seems debatable. They have limited sensitivity and specificity at least in the identification of some infectious agents or, as in the case of NxTAG RPP, they have not been evaluated in a sufficient number of patients to allow definitive conclusions. In the future, the clinical relevance of multiplex assays, including NxTAG RPP, could significantly increase, mainly because a number of new antiviral agents effective against several respiratory viruses for which no drug is presently available will be marketed. In addition, it is highly likely that the efficiency of multiplex assays will be significantly improved.

A generalized dose-response relationship for adenovirus infection and illness by exposure pathway

Adenoviruses are found everywhere in the environment, and cause various health problems including symptoms of enteric illness, and respiratory illness. Despite their significance to public health, few studies have addressed the health risks associated with exposure to adenovirus. Human challenge studies have been published for a few adenoviruses, which involved exposure through oral ingestion, inhalation, intranasal and intraocular droplet inoculation. Nothwithstanding the different symptoms resulting from such exposures, infection can be defined as colonization of a corresponding mucosa. A two-level dose-response model was developed to describe the distributions of infectivity and pathogenicity in various challenge studies of adenovirus, incorporating differences in inoculation route as shift in average infectivity and pathogenicity. This dose-response model can be used to make predictions for the infectivity of adenovirus, specific to any of the four studied inoculation methods. The generalized adenovirus dose-response relationship for infection and acute illness takes into account variation in infectivity and/or pathogenicity across adenovirus types, as well as uncertainty due to limited data.

Diagnosis of Pediatric Acute Adenovirus Infections: Is a Positive PCR Sufficient?

BACKGROUND

Human adenovirus (HAdV), especially species C (HAdV-C), can be detected incidentally by polymerase chain reaction in nasopharyngeal (NP) samples, making it difficult to interpret clinical significance of a positive result. We classified patients into groups based on HAdV culture positivity from respiratory specimens and the presence of an identified co-pathogen. We hypothesized that HAdV-C would be over-represented and viral burden would be lower in patients most likely to have incidental detection (ie, with a negative viral culture and documented co-pathogen).

METHODS

Immunocompetent children with HAdV + nasopharyngeal specimens were classified into 4 groups: group I (HAdV culture (+) and no co-infection), group II (culture (+) and co-infection), group III (culture (-) and no co-infection) and group IV (culture (-) and co-infection). Viral burden (cycle threshold) and species were compared among groups.

RESULTS

Of 483 nasopharyngeal specimens, HAdV was isolated in culture in 252 (52%); co-infection was found in 265 (55%) patients. Group I (most consistent with acute disease) had significantly lower cycle thresholds (median 23.9; interquarile range 22.2-28.1) compared with group IV (most consistent with incidental detection; median 37.3; interquarile range 35.3-38.9; P < 0.0001). HAdV-C accounted for 41% samples of group I and 83% of group IV (P < 0.0001). We identified a subset of 22 patients with bacterial or fungal co-pathogens, 18 of whom had no growth on viral culture (group IV) with a median cycle threshold of 37.4 (interquarile range 33.9-39.2).

CONCLUSIONS

Species identification and viral burden may assist in interpretation of a positive HAdV result. Low viral burden with HAdV-C may be consistent with incidental detection.

Outbreak of adenovirus type 55 infection in Israel

BACKGROUND

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

OBJECTIVES

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

STUDY DESIGN

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

RESULTS

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

CONCLUSIONS

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

Seasonal difference of human adenoviruses in a subtropical river basin based on 1-year monthly survey

In this study, the seasonal difference and the observable presence/absence of human adenovirus (HAdV) in the Puzih River basin in Taiwan was investigated. A total of 288 water samples were collected from 24 sites from March 2014 to February 2015. Human AdV analysis of sample was subjected to viral concentration using a GN-6 Metricel® filter, followed by DNA extraction, nested-PCR, and qPCR. Human AdV was detected in 34.3 % (99/288) of the entire river water sample. A higher percentage of HAdV (76.4 %) was obtained during the winter. The HAdV median concentration was relatively high in fall (1.4 × 10(3) copies/L) and winter (2.8 × 10(3) copies/L). Significant difference and correlation were found between the seasonal variation of HAdV and water quality parameters, including heterotrophic plate count, total coliform, water temperature, and turbidity. The most frequently identified HAdV (subgenus F) serotype was 41. Human AdV-41 is the main cause of gastroenteritis and should be considered for associated human health risk potential in the Puzih River basin.

Nested-PCR and TaqMan real-time quantitative PCR assays for human adenoviruses in environmental waters

Human adenovirus (HAdV) infections can occur throughout the year. Cases of HAdV-associated respiratory disease have been more common in the late winter, spring, and early summer. In this study, to provide viral pollution data for further epidemiological studies and governmental actions, the presence of HAdV in the aquatic environment was quantitatively surveyed in the summer. This study was conducted to compare the efficiencies of nested-PCR (polymerase chain reaction) and qPCR (quantitative PCR) for detecting HAdV in environmental waters. A total of 73 water samples were collected from Puzi River in Taiwan and subjected to virus concentration methods. In the results, qPCR had much better efficiency for specifying the pathogen in river sample. HAdV41 was detected most frequently in the river water sample (10.9%). The estimated HAdV concentrations ranged between 6.75 × 10(2) and 2.04 × 10(9) genome copies/L. Significant difference was also found in heterotrophic plate counts, conductivity, water temperature, and water turbidity between presence/absence of HAdV. HAdV in the Puzi River may pose a significant health risk.

Adenoviruses and acute respiratory infections in children living in an equatorial area of Brazil

Human adenoviruses (HAdVs) are important respiratory pathogens, found in 2–27% of acute respiratory infection (ARI) cases. Few studies have analysed the diversity of species and types of HAdVs associated with ARI in Brazil. The purpose of this study was to determine the circulation patterns of the different HAdV species and respective types associated with ARI in children in the city of Fortaleza, northeastern Brazil. HAdVs were screened by an indirect immunofluorescence assay, and subsequently identified as species and types by PCR and sequencing of the hexon gene (HVR1–HVR6). Between 2001 and 2013, a total of 290 HAdV strains were detected, 190 of which were identified as belonging to the HAdV-B, -C and -E species. Seven types of HAdVs circulated in the studied population during the analysed period, with HAdV-3 being predominant.

Adenovirus pneumonia complicated with acute respiratory distress syndrome: a case report

Severe adenovirus infection in children can manifest with acute respiratory distress syndrome (ARDS) and respiratory failure, leading to the need for prolonged mechanical support in the form of either mechanical ventilation or extracorporeal life support. Early extracorporeal membrane oxygenation (ECMO) intervention for children with ARDS should be considered if selection criteria fulfill.We report on a 9-month-old boy who had adenovirus pneumonia with rapid progression to ARDS. Real-time polymerase chain reaction tests of sputum and pleural effusion samples confirmed adenovirus serotype 7. Chest x-rays showed progressively increasing infiltrations and pleural effusions in both lung fields within 11 days. Because conventional ARDS therapies failed, we initiated ECMO with high-frequency oscillatory ventilation (HFOV) for 9 days. Chest x-rays showed gradual improvements in lung expansion.This patient was subsequently discharged after a hospital stay of 38 days. Post-ECMO and adenovirus sequelae were followed in our outpatient department.Adenovirus pneumonia in children can manifest with severe pulmonary morbidity and respiratory failure. The unique lung recruitment by HFOV can be a useful therapeutic option for severe ARDS patients when combined with sufficient lung rest provided by ECMO.

Structure, function and dynamics in adenovirus maturation

Here we review the current knowledge on maturation of adenovirus, a non-enveloped icosahedral eukaryotic virus. The adenovirus dsDNA genome fills the capsid in complex with a large amount of histone-like viral proteins, forming the core. Maturation involves proteolytic cleavage of several capsid and core precursor proteins by the viral protease (AVP). AVP uses a peptide cleaved from one of its targets as a "molecular sled" to slide on the viral genome and reach its substrates, in a remarkable example of one-dimensional chemistry. Immature adenovirus containing the precursor proteins lacks infectivity because of its inability to uncoat. The immature core is more compact and stable than the mature one, due to the condensing action of unprocessed core polypeptides; shell precursors underpin the vertex region and the connections between capsid and core. Maturation makes the virion metastable, priming it for stepwise uncoating by facilitating vertex release and loosening the condensed genome and its attachment to the icosahedral shell. The packaging scaffold protein L1 52/55k is also a substrate for AVP. Proteolytic processing of L1 52/55k disrupts its interactions with other virion components, providing a mechanism for its removal during maturation. Finally, possible roles for maturation of the terminal protein are discussed.

Postinfectious bronchiolitis obliterans in children: the South American contribution

Postinfectious bronchiolitis obliterans (PIBO) is an infrequent chronic lung that causes irreversible obstruction and, or, obliteration of the smaller airways. This review particularly focuses on more than 30 studies from South America.

CONCLUSION

The initial PIBO event occurs in the early years of life and is strongly associated with adenovirus infection and the need for mechanical ventilator support. Treatment requires a multidisciplinary strategy. Multicentre studies are needed to determine progression, optimal management and long-term follow-up.

Serotype determination of adenoviruses in children with respiratory infection

OBJECTIVE

To determine adenovirus serotypes among children with acute respiratory infection (ARI) in Khoozestan province, Iran during years 2010-2011.

METHODS

One hundred sixty three nasopharyngeal swabs were collected from children between 1 and 15 y who were hospitalized for the acute respiratory infection. The viral DNA was extracted from the nasopharyngeal swabs and adenoviruses were detected by Nested PCR. Positive PCR samples were sequenced in order to confirm the adenovirus serotypes.

RESULTS

Out of 163 samples, 30 (18.4 %) were positive for adenoviruses by nested PCR. Twenty two PCR products were sequenced and recognized as Ad5 and Ad2 serotypes including 19 (86.3 %) Ad5 and 3 (13.7 %) Ad2.

CONCLUSIONS

This study reveals that adenoviruses with Ad5 predominance are important cause of respiratory tract infection in children.

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.

Respiratory virus detection in nasopharyngeal aspirate versus bronchoalveolar lavage is dependent on virus type in children with chronic respiratory symptoms

Background

The comparative yield of respiratory virus detection from nasopharyngeal aspirate (NPA) versus bronchoalveolar lavage (BAL) is uncertain. Furthermore, the significance of virus detection and its relationship to lower airway neutrophilic inflammation is poorly studied.

Objectives

To evaluate the sensitivity, specificity and predictive values of NPA for detecting respiratory viruses in BAL; and to determine the relationship between viruses and lower airway neutrophilia in children with non-acute respiratory illness.

Study design

150 paired NPA and BAL samples were obtained from 75 children aged <18 years undergoing flexible bronchoscopy for investigation of chronic respiratory symptoms. Viral studies were performed using polymerase chain reaction (PCR). Cellularity studies were performed on BALs. Diagnostic parameters of NPA compared to BAL and associations between viruses and lower airway %neutrophils were evaluated.

Results

NPA had a higher yield than BAL for detection of any respiratory virus (52 versus 38, respectively). NPA had a high sensitivity (92%) and low specificity (57%) for detecting HRV in BAL with poor kappa agreement value of 0.398 (95% CI 0.218–0.578, p < 0.001). NPA had a fair sensitivity (69%) and good specificity (90.3%) for detecting HAdV on BAL, kappa agreement was 0.561 (95% CI 0.321–0.801, p < 0.001). HAdV positivity on NPA, compared to negativity, was independently associated with heightened airway neutrophilia [mean difference (95% CI): 18 (1,35); p = 0.042].

Conclusions

NPA has a higher yield for respiratory virus detection than BAL, however its diagnostic accuracy is dependent on viral species. Adenovirus positivity is associated with significantly heightened lower airway neutrophilia in children with chronic respiratory symptoms.

Other viral pneumonias: coronavirus, respiratory syncytial virus, adenovirus, hantavirus

Severe viral pneumonia is an increasing problem among adults. The incidence and number of viruses known to cause pneumonia and respiratory failure have also expanded in recent years. This article provides an overview of severe respiratory disease caused by coronavirus, respiratory syncytial virus, adenovirus, and hantavirus. These emerging pathogens are easily overlooked and timely diagnosis requires a high index of suspicion and confirmation by molecular testing. Management of individual cases is mainly supportive and requires institution of appropriate infection control measures. Vaccines and effective therapeutics for these potentially devastating respiratory viruses are urgently required.

Survival of Respiratory Viruses on Fresh Produce

In addition to enteric viruses of fecal origin, emerging zoonotic viruses such as respiratory coronaviruses and influenza viruses may potentially be transmitted via contaminated foods. The goal of this study was to determine the recovery efficiencies and the survival of two respiratory viruses, namely, adenovirus 2 (Ad2) and coronavirus 229E (CoV229E), on fresh produce in comparison to the enteric poliovirus 1 (PV1). Adenovirus was recovered with efficiencies of 56.5, 31.8, and 34.8 % from lettuce, strawberries, and raspberries, respectively. Coronavirus was recovered from lettuce with an efficiency of 19.6 % yet could not be recovered from strawberries. Poliovirus was recovered with efficiencies of 76.7 % from lettuce, but only 0.06 % from strawberries. For comparison purposes, the survival of Ad2, CoV229E, and PV1 was determined for periods up to 10 days on produce. The enteric PV1 survived better than both respiratory viruses on lettuce and strawberries, with only ≤1.03 log10 reductions after 10 days of storage at 4 °C compared to CoV229E not being recovered after 4 days on lettuce and reductions of 1.97 log10 and 2.38 log10 of Ad2 on lettuce and strawberries, respectively, after 10 days. Nevertheless, these respiratory viruses were able to survive for at least several days on produce. There is therefore the potential for transfer to the hands and subsequently to the mucosa via rubbing the eyes or nose. In addition, some respiratory coronaviruses (e.g., severe acute respiratory syndrome coronavirus) and adenoviruses are also capable of replication in the gut and there is thus some potential for acquisition through the consumption of contaminated produce.

Epidemiological analysis of respiratory viral etiology for influenza-like illness during 2010 in Zhuhai, China

BACKGROUND

Influenza-like illnesses (ILI), a subset of acute respiratory infections (ARI), are a significant source of morbidity and mortality worldwide. ILI can be caused by numerous pathogens, however; there is limited information on the etiology and epidemiology of ILI in China.

METHODS

We performed a one-year surveillance study (2010) of viral etiology causing ILI and investigated the influence of climate on outbreaks of ILI attributed to viruses at the Outpatient Department of Zhuhai Municipal People's Hospital in Zhuhai, China.

RESULTS

Of the 337,272 outpatients who sought attention in the Outpatient Department of Zhuhai Municipal People's Hospital in 2010, 3,747 (1.11%) presented with ILI. Of these patients presenting with ILI, 24.66% (924/3,747) had available samples and were enrolled in this study. At least one respiratory virus was identified in 411 patients (44.48%) and 42 (4.55%) were co-infected with two viruses. In patients co-infected with two viruses, respiratory syncytial virus (RSV) was detected in 50% (21/42). Among common viral pathogens detected, significant differences in age distributions were observed in seasonal influenza virus A (sFulA, H3N2) and B (sFluB), pandemic H1N1 2009 influenza viruses (H1N1pdm09), RSV, and adenovirus (ADV). Infections with sFluA (H3N2), sFluB, RSV, and human metapneumovirus (HMPV) had characteristic seasonal patterns. The incidences of sFluA (H3N2), ADV, and RSV correlated with air temperature. Alternatively, the incidence of sFluB correlated with relative air humidity.

CONCLUSIONS

These results demonstrate that a wide range of respiratory viral pathogens are circulating in Zhuhai city. This information needs to be considered by clinicians when treating patients presenting with ILI.

A molecular epidemiology survey of respiratory adenoviruses circulating in children residing in Southern Palestine

A molecular epidemiology survey was performed in order to establish and document the respiratory adenovirus pathogen profiles among children in Southern Palestine. Three hundred and thirty-eight hospitalized pediatric cases with adenovirus-associated respiratory tract infections were analyzed. Forty four cases out of the 338 were evaluated in more detail for the adenoviruses types present. All of the children resided in Southern Palestine, that is, in city, village and refugee camp environments within the districts of Hebron and Bethlehem. Human adenoviruses circulated throughout 2005–2010, with major outbreaks occurring in the spring months. A larger percent of the children diagnosed with adenoviral infections were male infants. DNA sequence analysis of the hexon genes from 44 samples revealed that several distinct adenovirus types circulated in the region; these were HAdV-C1, HAdV-C2, HAdV-B3 and HAdV-C5. However, not all of these types were detected within each year. This is the first study ever conducted in Palestine of the genetic epidemiology of respiratory adenovirus infections.

Prolonged mechanical support in children with severe adenoviral infections: a case series and review of the literature

Adenovirus infections occur primarily in infants and children less than 5 years of age, accounting for 2% to 5% of respiratory illnesses in the pediatric population and 4% to 10% of childhood pneumonias. Although the majority of children with adenovirus disease develop mild upper respiratory tract disease, more severe disease may occur with involvement of the lower respiratory tract characterized by pneumonitis and/or small airways disease. The authors present a case series of 3 high-risk children with severe lower respiratory tract adenoviral infections. These cases demonstrate the potential for the development of severe respiratory involvement from adenovirus in infants and children with comorbid conditions and illustrate that there may be a rapid progression of the disease as well as the need, in selected circumstances, for prolonged mechanical support. We review the role of adenovirus in lower respiratory tract infections in infants and children, its potential to result in life-threatening complications in pediatric patients with comorbid conditions, and the potential life-saving role of mechanical ventilation and extracorporeal life support (ECLS) in these children.

An outbreak of adenovirus type 7 in a residential facility for severely disabled children

BACKGROUND

Adenoviruses cause a variety of clinical symptoms, involving the respiratory, gastrointestinal, urogenital, and neurologic systems. Only a few of the 55 known serotypes of adenovirus that affect humans can cause outbreaks of respiratory tract infection.

AIM

To describe the characteristics and clinical manifestations of severe respiratory disease contracted by 8 physically and cognitively disabled children during a very short outbreak of adenovirus serotype 7 infection in a residential facility.

METHODS

The clinical, imaging, and laboratory findings of the patients who were hospitalized with severe respiratory symptoms were retrospectively reviewed. Molecular typing of the adenovirus was performed.

RESULTS

During 10 days in February 2010, 8 severely disabled children, 9 months to 5 years of age (median 22.5 months), from the same residential facility, were hospitalized due to severe acute respiratory disease with hypoxemia. Four of them (50%) needed mechanical ventilation for 2 to 8 days and one developed multisystem failure, including acute renal failure. Adenovirus serotype 7 was detected in the respiratory specimens of all 8 children. Two patients were treated with intravenous cidofovir. All 8 patients survived and were discharged after hospitalization of 6 to 15 (median: 11.5) days. The epidemiologic investigation revealed that all the 8 affected children shared a playroom and a caregiver worked with them while suffering fever, sore throat, and conjunctivitis before the onset of the outbreak.

CONCLUSIONS

Adenovirus type 7 may cause short outbreaks of infection in institutions, causing children to develop life-threatening disease. Early detection of pathogens causing respiratory infections in institutions, isolation, and other preventive precautions are advocated. Moreover, vaccination of health care providers in institutions with the currently available live, oral adenovirus vaccine for types 4 and 7 should be considered.

Severe community-acquired adenovirus pneumonia in an immunocompetent 44-year-old woman: a case report and review of the literature

INTRODUCTION

This case report describes a rare condition: community-acquired adenovirus pneumonia in an immunocompetent adult. The diagnosis was achieved by using a multiplex real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay and highlights the usefulness of these novel molecular diagnostic techniques in patients hospitalized with acute respiratory illness. We also performed a literature search for previously published cases and present a summary of the clinical, laboratory and radiological features of this condition.

CASE PRESENTATION

A 44-year-old immunocompetent Caucasian woman was admitted to our hospital with an acute febrile respiratory illness associated with a rash. Her blood tests were non-specifically abnormal, and tests for bacterial pathogens were negative. Her condition rapidly deteriorated while she was in our hospital and required mechanical ventilation and inotropic support. A multiplex real-time RT-PCR assay performed on respiratory specimens to detect respiratory viruses was negative for influenza but positive for adenovirus DNA. The patient recovered on supportive treatment, and antibiotics were stopped after 5 days.

CONCLUSIONS

Community-acquired adenovirus pneumonia in immunocompetent adult civilians presents as a non-specific acute febrile respiratory illness followed by the abrupt onset of respiratory failure, often requiring mechanical ventilation. Its laboratory and radiological features are typical of viral infections but also are non-specific. Novel multiplex real-time RT-PCR testing for respiratory viruses enabled us to rapidly make the diagnosis in this case. The new technology could be used more widely in patients with acute respiratory illness and has potential utility for rationalization of the use of antibiotics and improving infection control measures.

Frequent detection of respiratory viruses without symptoms: toward defining clinically relevant cutoff values

Highly sensitive techniques, such as PCR, have greatly improved the detection of respiratory viruses. However, the sensitivity of PCR tests also complicates clinical interpretation, as the presence of small amounts of viral targets may not necessarily have clinical relevance. We performed a prospective case-control study in asymptomatic and symptomatic young children. PCR detection of 14 respiratory viruses was performed in nasal washes, and results were quantified in copies per milliliter. A total of 141 cases and 157 controls were included. In 72% of the cases and 28% of the controls, at least one virus was identified. When stratified for age, at least one virus was identified in 47% of the controls younger than 1 year old. Rhinovirus (RV) was frequently detected in both symptomatic and asymptomatic individuals. Receiver operating characteristic analysis for quantitative rhinovirus detection showed that cutoff values for clinical relevance are feasible for RV. In contrast to rhinovirus, respiratory syncytial virus (RSV) was rarely detected in controls, suggesting that a positive RSV test result is almost always of clinical relevance, independent of viral quantity. In conclusion, our study shows that asymptomatic carriage of a respiratory virus occurs frequently in young children. However, significant differences in the amount of virus present were observed between cases and controls. This suggests that defining cutoff levels should be feasible and represents the next necessary step for diagnosing viral respiratory infections using molecular tests.

Enhancement of respiratory mucosal antiviral defenses by the oxidation of iodide

Recent reports postulate that the dual oxidase (DUOX) proteins function as part of a multicomponent oxidative pathway used by the respiratory mucosa to kill bacteria. The other components include epithelial ion transporters, which mediate the secretion of the oxidizable anion thiocyanate (SCN(-)) into airway surface liquid, and lactoperoxidase (LPO), which catalyzes the H(2)O(2)-dependent oxidation of the pseudohalide SCN(-) to yield the antimicrobial molecule hypothiocyanite (OSCN(-)). We hypothesized that this oxidative host defense system is also active against respiratory viruses. We evaluated the activity of oxidized LPO substrates against encapsidated and enveloped viruses. When tested for antiviral properties, the LPO-dependent production of OSCN(-) did not inactivate adenovirus or respiratory syncytial virus (RSV). However, substituting SCN(-) with the alternative LPO substrate iodide (I(-)) resulted in a marked reduction of both adenovirus transduction and RSV titer. Importantly, well-differentiated primary airway epithelia generated sufficient H(2)O(2) to inactivate adenovirus or RSV when LPO and I(-) were supplied. The administration of a single dose of 130 mg of oral potassium iodide to human subjects increased serum I(-) concentrations, and resulted in the accumulation of I(-) in upper airway secretions. These results suggest that the LPO/I(-)/H(2)O(2) system can contribute to airway antiviral defenses. Furthermore, the delivery of I(-) to the airway mucosa may augment innate antiviral immunity.

Ebola haemorrhagic fever

Ebola viruses are the causative agents of a severe form of viral haemorrhagic fever in man, designated Ebola haemorrhagic fever, and are endemic in regions of central Africa. The exception is the species Reston Ebola virus, which has not been associated with human disease and is found in the Philippines. Ebola virus constitutes an important local public health threat in Africa, with a worldwide effect through imported infections and through the fear of misuse for biological terrorism. Ebola virus is thought to also have a detrimental effect on the great ape population in Africa. Case-fatality rates of the African species in man are as high as 90%, with no prophylaxis or treatment available. Ebola virus infections are characterised by immune suppression and a systemic inflammatory response that causes impairment of the vascular, coagulation, and immune systems, leading to multiorgan failure and shock, and thus, in some ways, resembling septic shock.

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

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

Molecular diagnosis of respiratory viruses

Respiratory tract viral infections are responsible for an incredible amount of morbidity and mortality throughout the world. Older diagnostic methods, such as tissue culture and serology, have been replaced with more advanced molecular techniques, such as PCR and reverse-transcriptase PCR, nucleic acid sequence-based amplification and loop-mediated isothermal amplification. These techniques are faster, have greater sensitivity and specificity, and are becoming increasingly accessible. In the minds of most, PCR has replaced tissue culture and serology as the gold standard for detection of respiratory viruses owing to its speed, availability and versatility. PCR/reverse-transcriptase PCR has been used in a variety of detection platforms, in multiplex assays (detecting multiple pathogens simultaneously) and in automated systems (sample in-answer out devices). Molecular detection has many proven advantages over standard virological methods and will further separate itself through increased multiplexing, processing speed and automation. However, tissue culture remains an important method for detecting novel viral mutations within a virus population, for detecting novel viruses and for phenotypic characterization of viral isolates.

Persistence of adenovirus nucleic acids in nasopharyngeal secretions: a diagnostic conundrum

BACKGROUND

Polymerase chain reaction (PCR) assays increase the rate of viral detection in clinical specimens, compared with conventional virologic methods. Studies suggest that PCR may detect virus nucleic acid (NA) that persists in the respiratory tract.

METHODS

We analyzed virologic data from children having frequent upper respiratory infections (URI), who were followed up in a longitudinal study. Nasopharyngeal secretions were collected at URI onset and when acute otitis media was diagnosed; virus studies were performed using conventional diagnostics and PCR. Repeated presence of adenovirus by PCR was further studied by sequencing and phylogenetic analysis.

RESULTS

Of 581 URI episodes in 76 children, 510 viruses were detected. Of the viruses detected by PCR, 15% were those detected previously; repeated positives occurred most frequently with adenovirus. Sequencing results were available in 13 children with repeated adenovirus detection; the following 4 patterns of infection were identified (16 instances): (1) adenovirus of the same serotype and strain detected continuously (n = 8 instances), (2) adenovirus of different serotypes detected during sequential URI episodes (n = 3), (3) adenovirus of the same serotype but different strains detected during sequential URI episodes (n = 3), and (4) adenovirus of the same serotype and strain detected intermittently (n = 2).

CONCLUSIONS

Among children with frequent URIs, repeated positive PCR results for adenovirus NA may represent a new serotype/strain, or persistence of viral NA. Results must be interpreted with caution; clinical correlation and presence of other viruses are important. Further longitudinal studies of children during and after infection are required for better understanding of the clinical significance of positive PCR tests for adenovirus NA in the respiratory tract.

The role of adenovirus in respiratory tract infections

Adenovirus plays a significant role in respiratory tract disease in pediatric and adult patients. It has been linked to outbreaks and epidemics in various patient populations, resulting in considerable morbidity and mortality. In this article, we discuss the epidemiology, pathogenesis, respiratory tract illnesses and complications, and roles of potential treatment options. The role of the past oral adenovirus vaccine and the military implications of its withdrawal from routine use in military recruits is discussed as well.

Quantitative detection of human adenoviruses in wastewater and combined sewer overflows influencing a Michigan river

Enteric viruses are important pathogens found in contaminated surface waters and have previously been detected in waters of the Great Lakes. Human adenoviruses were monitored because of their high prevalence and persistence in aquatic environments. In this study, we quantified adenoviruses in wastewater, surface water, and combined sewer overflows (CSOs) by real-time PCR. Between August 2005 and August 2006, adenovirus concentrations in raw sewage, primary-treated effluent, secondary-treated effluent, and chlorinated effluent from a wastewater treatment plant in Michigan were examined. CSO samples (n = 6) were collected from a CSO retention basin in Grand Rapids, MI. Adenoviruses were detected in 100% of wastewater and CSO discharge samples. Average adenovirus DNA concentrations in sewage and CSOs were 1.15 x 10(6) viruses/liter and 5.35 x 10(5) viruses/liter, respectively. Adenovirus removal was <2 log(10) (99%) at the wastewater treatment plant. Adenovirus type 41 (60% of clones), type 12 (29%), type 40 (3%), type 2 (3%), and type 3 (3%) were isolated from raw sewage and primary effluents (n = 28). Six of 20 surface water samples from recreational parks at the lower Grand River showed virus concentrations above the real-time PCR detection limit (average, 7.8 x 10(3) viruses/liter). This research demonstrates that wastewater effluents and wastewater-impacted surface waters in the lower Grand River in Michigan contain high levels of viruses and may not be suitable for full-body recreational activities. High concentrations of adenovirus in these waters may be due to inefficient removal during wastewater treatment and to the high persistence of these viruses in the environment.