Emergent severe acute respiratory distress syndrome caused by adenovirus type 55 in immunocompetent adults in 2013: a prospective observational study

Neutralizing monoclonal antibodies protect against human adenovirus type 55 infection in transgenic mice and tree shrews

Re-emerging human adenovirus type 55 (HAdV55) has become a significant threat to public health due to its widespread circulation and the association with severe pneumonia, but an effective anti-HAdV55 agent remains unavailable. Herein, we report the generation of macaque-derived, human-like monoclonal antibodies (mAbs) protecting against HAdV55 infection with high potency. Using fluorophore-labelled HAdV55 virions as probes, we isolated specific memory B cells from rhesus macaques (Macaca mulatta) that were immunized twice with an experimental vaccine based on E1-, E3-deleted, replication-incompetent HAdV55. We cloned a total of 19 neutralizing mAbs, nine of which showed half-maximal inhibitory concentrations below 1.0 ng/ml. These mAbs recognized the hyper-variable-region (HVR) 1, 2, or 7 of viral hexon protein, or the fibre knob. In transgenic mice expressing human desmoglein-2, the major cellular receptor for HAdV55, a single intraperitoneal injection with hexon-targeting mAbs efficiently prevented HAdV55 infection, and mAb 29C12 showed protection at a dose as low as 0.004 mg/kg. Fibre-targeting mAb 28E8, however, showed protection only at a dose up to 12.5 mg/kg. In tree shrews that are permissive for HAdV55 infection and disease, mAb 29C12 effectively prevented HAdV55-caused pneumonia. Further analysis revealed that fibre-targeting mAbs blocked the attachment of HAdV55 to host cells, whereas hexon-targeting mAbs, regardless of their targeting HVRs, mainly functioned at post-attachment stage via inhibiting viral endosomal escape. Our results indicate that hexon-targeting mAbs have great anti-HAdV55 activities and warrant pre-clinical and clinical evaluation.

Prevalence and clinical relevance of viraemia in viral respiratory tract infections: a systematic review

In this Review, we analysed the prevalence of viraemia during infection with SARS-CoV-2 and other relevant respiratory viruses, including other human coronaviruses such as MERS-CoV and SARS-CoV, adenovirus, human metapneumovirus, human rhinovirus/enterovirus, influenza A and B virus, parainfluenza virus, and respiratory syncytial virus. First, a preliminary systematic search was conducted to identify articles published before May 23, 2024 that reported on viraemia during infection with respiratory viruses. The articles were then analysed for relevant terms to identify the prevalence of viraemia, its association with the disease severity and long-term consequences, and host responses. A total of 202 articles were included in the final study. The pooled prevalence of viraemia was 34% for SARS-CoV-2 and between 6% and 65% for other viruses. Association of viraemia with disease severity was extensively reported for SARS-CoV-2 and also for SARS-CoV, MERS-CoV, adenoviruses, rhinoviruses, respiratory syncytial virus, and influenza A(H1N1)pdm09 (albeit with low evidence). SARS-CoV-2 viraemia was linked to memory problems and worsened quality of life. Viraemia was associated with signatures denoting dysregulated host responses. In conclusion, the high prevalence of viraemia and its association with disease severity suggests that viraemia could be a relevant pathophysiological event with important translational implications in respiratory viral infections.

Generation of Human Embryonic Stem Cell-Derived Lung Organoids for Modeling Infection and Replication Differences between Human Adenovirus Types 3 and 55 and Evaluating Potential Antiviral Drugs

Human adenoviruses type 3 (HAdV-3) and type 55 (HAdV-55) are frequently encountered, highly contagious respiratory pathogens with high morbidity rate. In contrast to HAdV-3, one of the most predominant types in children, HAdV-55 is a reemergent pathogen associated with more severe community-acquired pneumonia (CAP) in adults, especially in military camps. However, the infectivity and pathogenicity differences between these viruses remain unknown as in vivo models are not available. Here, we report a novel system utilizing human embryonic stem cells-derived 3-dimensional airway organoids (hAWOs) and alveolar organoids (hALOs) to investigate these two viruses. Firstly, HAdV-55 replicated more robustly than HAdV-3. Secondly, cell tropism analysis in hAWOs and hALOs by immunofluorescence staining revealed that HAdV-55 infected more airway and alveolar stem cells (basal and AT2 cells) than HAdV-3, which may lead to impairment of self-renewal functions post-injury and the loss of cell differentiation in lungs. Additionally, the viral life cycles of HAdV-3 and -55 in organoids were also observed using Transmission Electron Microscopy. This study presents a useful pair of lung organoids for modeling infection and replication differences between respiratory pathogens, illustrating that HAdV-55 has relatively higher replication efficiency and more specific cell tropism in human lung organoids than HAdV-3, which may result in relatively higher pathogenicity and virulence of HAdV-55 in human lungs. The model system is also suitable for evaluating potential antiviral drugs, as demonstrated with cidofovir. IMPORTANCE Human adenovirus (HAdV) infections are a major threat worldwide. HAdV-3 is one of the most predominant respiratory pathogen types found in children. Many clinical studies have reported that HAdV-3 causes less severe disease. In contrast, HAdV-55, a reemergent acute respiratory disease pathogen, is associated with severe community-acquired pneumonia in adults. Currently, no ideal in vivo models are available for studying HAdVs. Therefore, the mechanism of infectivity and pathogenicity differences between human adenoviruses remain unknown. In this study, a useful pair of 3-dimensional (3D) airway organoids (hAWOs) and alveolar organoids (hALOs) were developed to serve as a model. The life cycles of HAdV-3 and HAdV-55 in these human lung organoids were documented for the first time. These 3D organoids harbor different cell types, which are similar to the ones found in humans. This allows for the study of the natural target cells for infection. The finding of differences in replication efficiency and cell tropism between HAdV-55 and -3 may provide insights into the mechanism of clinical pathogenicity differences between these two important HAdV types. Additionally, this study provides a viable and effective in vitro tool for evaluating potential anti-adenoviral treatments.

Machine learning for the identification of respiratory viral attachment machinery from sequences data

At the outset of an emergent viral respiratory pandemic, sequence data is among the first molecular information available. As viral attachment machinery is a key target for therapeutic and prophylactic interventions, rapid identification of viral "spike" proteins from sequence can significantly accelerate the development of medical countermeasures. For six families of respiratory viruses, covering the vast majority of airborne and droplet-transmitted diseases, host cell entry is mediated by the binding of viral surface glycoproteins that interact with a host cell receptor. In this report it is shown that sequence data for an unknown virus belonging to one of the six families above provides sufficient information to identify the protein(s) responsible for viral attachment. Random forest models that take as input a set of respiratory viral sequences can classify the protein as "spike" vs. non-spike based on predicted secondary structure elements alone (with 97.3% correctly classified) or in combination with N-glycosylation related features (with 97.0% correctly classified). Models were validated through 10-fold cross-validation, bootstrapping on a class-balanced set, and an out-of-sample extra-familial validation set. Surprisingly, we showed that secondary structural elements and N-glycosylation features were sufficient for model generation. The ability to rapidly identify viral attachment machinery directly from sequence data holds the potential to accelerate the design of medical countermeasures for future pandemics. Furthermore, this approach may be extendable for the identification of other potential viral targets and for viral sequence annotation in general in the future.

Interleukin-6 serum levels are independently associated with severe adenovirus pneumonia in children: a cross-sectional study

BACKGROUND

This study aimed to explore the potential association between interleukin-6 (IL-6) serum levels and severe adenovirus pneumonia (SAP) in children.

METHODS

A retrospective hospital-based cross-sectional study was conducted on children with SAP who presented to the Tianjin Children's Hospital between January 2019 and December 2020. Serum IL-6 levels were categorized into quintiles (Q1-5). The primary outcome variable was the occurrence of SAP. The patients' clinical features, laboratory findings, and radiographic characteristics were also assessed, and a descriptive bivariate analysis was carried out. Multivariable logistic regression analysis was applied to evaluate the relationship of IL-6 with SAP after adjustment for confounders. The nonlinear relationship between IL-6 and SAP was also analyzed. P value <0.05 was considered statistically significant.

RESULTS

In total, 542 patients met our inclusion criteria (223 males and 319 females). The mean IL-6 serum level was 38.51 pg/mL (range, 1.50-659.2 pg/mL). After adjustment for confounders, the odds ratio (OR) per SD (standard deviation) increase in IL-6 was 1.66 [95% confidence interval (CI): 1.14, 2.41]. The multivariable-adjusted OR (95% CI) of SAP across the Q1-Q5 categories of IL-6 were as follows: 1.00 (reference), 1.17 (0.59, 2.35), 1.79 (0.88, 3.63), 2.31 (1.12, 4.76), and 2.85 (1.32, 6.14) (P for trend =0.002). The risk of SAP increased with the IL-6 serum level up to 40.78 pg/mL (adjusted OR 1.029, 95% CI: 1.008-1.051; P=0.007); however, when the IL-6 level exceeded 40.78 pg/mL, it had no association with the risk of SAP (OR 1.003, 95% CI: 0.996-1.010; P=0.384).

CONCLUSIONS

Our findings suggest that the serum level of IL-6 is associated with the risk of SAP in children. The levels of IL-6 in children should therefore be of concern to clinicians.

An outbreak of acute respiratory disease caused by HAdV-55 in Beijing, China, 2020

Human adenoviruses (HAdVs) can cause acute respiratory diseases (ARDs) worldwide, and HAdV-55 is a reemergent pathogen in recent years. In the study, we investigated an outbreak of ARD at a school due to HAdV-55 in Beijing, China, during the early outbreak of coronavirus disease 2019 (COVID-19). The epidemic prevention team was dispatched to the school to collect epidemiologic data and nasopharyngeal samples. Then, real-time reverse transcription polymerase chain reaction (PCR) and multiplex PCR assays were used to detect severe acute respiratory syndrome coronavirus 2 and other respiratory pathogens, respectively. One representative HAdV-55 isolate was selected and submitted for whole-genome sequencing using a MiSeq system and the whole-genome phylogenetic tree was conducted based on the maximum likelihood method. The outbreak lasted from January 27 to February 6, 2020, and 108 students developed fever, among whom 60 (55.56%) cases were diagnosed with HAdV-55 infection in the laboratory using real-time PCR and 56 cases were hospitalized. All the confirmed cases had a fever and 11 cases (18.33%) presented with a fever above 39°C. Other main clinical symptoms included sore throat (43.33%) and headache (43.33%). We obtained and assembled the full genome of one isolate, BJ-446, with 34 761 nucleotides in length. HAdV-55 isolate BJ-446 was 99.85% identical to strain QS-DLL, which was the first HAdV-55 strain in China isolated from an ARD outbreak in Shanxi in 2006. One and four amino acid mutations were observed in the hexon gene and the coding region of L2 pV 40.1 kDa protein, respectively. We identified the first HAdV-55 infection associated with the ARD outbreak in Beijing since the emergence of COVID-19. The study suggests that improved surveillance of HAdV is needed, although COVID-19 is still prevalent in the world.

Case report: An unusual case of multisite embolism in a patient with adenovirus pneumoniae

A 36-year-old previous healthy man presented with fever, cough, and dyspnea associated with adenovirus pneumonia. The patient developed left ventricular thrombus, pulmonary embolism and multisite embolism of undetermined etiology. Adenovirus is a rare cause of thrombotic events in immunocompetent individuals, calling for further studies for early diagnosis and management.

Molecular typing and epidemiology profiles of human adenovirus infection among children with severe acute respiratory infection in Huzhou, China

Human adenoviruses (HAdVs) are prevalent worldwide and are a common cause of respiratory tract infection in people of all ages. However, little is known about HAdV infection among children with severe acute respiratory infection (SARI). The present study retrospectively analyzed the molecular typing and epidemiological characteristics of HAdV-positive samples from children with SARI from January 2017 to December 2021 in Huzhou. The results showed that 89 (8.27%) of 1078 SARI pediatric patients were positive for HAdVs. Children < 5 years of age accounted for 87.64% of the positive cases. The peak seasons for HAdV infection were the first quarter and the fourth quarter. In addition, HAdV-B and HAdV-C were circulating among pediatric patients with SARI, of which the B3 genotype (n = 30, 51.72%) was the most prevalent and was detected every year, indicating that B3 is the main epidemic strain in the Huzhou area, followed by C1 (n = 9, 15.52%), C2 (n = 7, 12.07%), and B7 (n = 5, 8.62%). These findings provide a benchmark for future epidemiology and prevention strategies for HAdVs.

Acute Respiratory Distress Syndrome Caused by Human Adenovirus in Adults: A Prospective Observational Study in Guangdong, China

Background

Viral causes of acute respiratory distress syndrome (ARDS) are mostly limited to influenza. However, adenovirus has been emerging as a cause of ARDS with a high mortality rate and described in adults are rare.

Methods

We conducted a prospective, single-center observational study of viral pneumonia with ARDS and confirmed adenovirus-associated ARDS in adults at our quaternary referral institution between March 2019 and June 2020. We prospectively analyzed clinical characteristics, laboratory test results, radiological characteristics, viral load from nasopharyngeal swabs and endotracheal aspirates, treatments, and outcomes for the study participants.

Results

The study enrolled 143 ARDS patients, including 47 patients with viral pneumonia-related ARDS, among which there were 14 adenovirus-associated ARDS patients, which accounted for 29.79% of the viral pneumonia-related ARDS cases. Among the adenovirus-associated ARDS patients, 78.57% were men with a mean age of 54.93 ± 19.04 years, younger than that of the non-adenovirus associated ARDS patients. Adenovirus-associated ARDS patients had no specific clinical characteristics, but they presented with decrease in the number of CD3+CD4+ T cells and higher serum creatinine during the early stage. The viral load and the positivity rate in the lower respiratory tract were higher than that of the upper respiratory tract in the patients with adenovirus-associated ARDS. All patients required invasive mechanical ventilation treatment. The average time from shortness of breath to the application of invasive ventilation was 24 h. Ten patients (71.43%) complicated by acute kidney injury, while 13 patients (71.43%) in the non-adenovirus associated ARDS group (P = 0.045). Additionally, 85.71% of the 14 adenovirus-associated ARDS patients survived. No significant differences were detected between the two groups regarding duration of ventilation, length of ICU stay and mortality.

Conclusion

Adenovirus infection is an important cause of virus-related ARDS. The positivity rate of adenovirus infection in lower respiratory tract secretions was higher than that in upper respiratory tract secretions in these patients. Age, lower CD3+CD4+ T cells, and high serum creatinine may be were associated with adenovirus induce ARDS in adults required mechanical ventilation. Early identification and intervention to prevent disease progression are essential for reducing the mortality rate in these patients.

Uncommon pathogens in an immunocompetent host: respiratory isolation of Cunninghamella bertholletiae, Aspergillus niger, Staphylococcus pseudintermedius and adenovirus in a patient with necrotising pneumonia

We present the unusual case of a 60-year-old immunocompetent woman with chronic obstructive pulmonary disease who developed a necrotising pneumonia with isolation of Cunninghamella bertholletiae, Aspergillus niger, Staphylococcus pseudintermedius and adenovirus. The patient recovered with antimicrobial therapy and supportive care in the intensive care unit. The current literature on diagnosis and treatment of these pathogens is reviewed.

Current status of human adenovirus infection in China

BACKGROUND

Outbreaks of severe, acute hepatitis among children have recently attracted global attention. The pathogen causing the outbreak remains unknown, but there is growing evidence that it may be associated with human adenovirus (HAdV).

DATA SOURCES

A review of adenovirus-related clinical studies, epidemiological studies, etiological studies, and case reports was conducted by reviewers independently.

RESULTS

HAdV can cause a wide variety of clinical symptoms. In the Mainland of China, HAdV infection accounts for 5.8%-13% of patients with acute respiratory infections, and these infections are mainly caused by species B, C, and E of HAdV. For acute conjunctivitis, 39.8%-74.9% of sporadic cases were infected by B and D species of HAdV. Outbreaks of keratoconjunctivitis and pharyngoconjunctival fever related to HAdV infection could be found throughout the country. In pediatric patients with acute gastroenteritis, HAdV-41 was the predominant HAdV type, followed by HAdV species B and C. Several types of HAdV, including HAdV-5, HAdV-7, HAdV-1, and HAdV-2, have previously been reported as potential pathogens associated with HAdV hepatitis in immunocompromised patients. However, few HAdV-related hepatitis cases have been reported in China to date.

CONCLUSIONS

There are no systematic surveillance and clinical studies on HAdV hepatitis in China. Therefore, it is imperative to establish a nationwide HAdV virological surveillance system to collect relevant clinical, epidemiological and virological surveillance data and risk factor information as soon as possible to assess the potential risk of HAdV hepatitis among children.

Severe pneumonia caused by human adenovirus type 55 in children

BACKGROUND

Emerging human adenovirus type 55 (HAdV-55) causes fatal pneumonia in adults. There is a lack of studies on severe pneumonia caused by HAdV-55 in children.

METHODS

We conducted a retrospective review of pediatric patients hospitalized at Guangzhou Women and Children's Medical Center with severe pneumonia from 2013 to 2020 who had human adenovirus (HAdV) detected in throat samples or bronchoalveolar lavage fluid using RT-PCR. The presence of HAdV-55 was determined by PCR amplification of the hypervariable regions of the hexon gene. Demographic, clinical, etiological, and outcome data were collected and analyzed.

RESULTS

Over the eight-year period, HAdV-55 was detected in three severe and six critical pediatric pneumonia patients. None of the patients had any underlying diseases, and had a median age of 18 months (range, 6-108 months). The male to female ratio was 2:1. All patients presented with fever and cough, and three patients presented with wheezing and diarrhea. Six patients had coinfections with other respiratory pathogens, such as bacteria, Mycoplasma pneumoniae and fungi. Three critical patients developed plastic bronchitis (PB). The median lengths of invasive mechanical ventilation and hospital stay of the critical patients were 10 (8, 28.75) days and 25 (13, 32.25) days, respectively. Three critical patients died, although two of them received extracorporeal membrane oxygenation (ECMO) and blood purification. Three surviving patients developed post-infectious bronchiolitis obliterans (PIBO) at the follow-up.

CONCLUSIONS

HAdV-55 can cause fatal pneumonia in children, and shows a high rate of co-infection with other respiratory pathogens and a poorer prognosis combined with PB. Thus, HAdV-55 may be an important subtype in patients with HAdV-induced pneumonia who develop PIBO.

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

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

Desmoglein 2 (DSG2) Is A Receptor of Human Adenovirus Type 55 Causing Adult Severe Community-Acquired Pneumonia

Human adenovirus type 55 (HAdV-B55) is a re-emergent acute respiratory disease pathogen that causes adult community-acquired pneumonia (CAP). Previous studies have shown that the receptor of HAdV-B14, which genome is highly similar with HAdV-B55, is human Desmoglein 2 (DSG2). However, whether the receptor of HAdV-B55 is DSG2 is undetermined because there are three amino acid mutations in the fiber gene between HAdV-B14 and HAdV-B55. Here, firstly we found the 3T3 cells, a mouse embryo fibroblast rodent cell line which does not express human DSG2, were able to be infected by HAdV-B55 after transfected with pcDNA3.1-DSG2, while normal 3T3 cells were still unsusceptible to HAdV-B55 infection. Next, A549 cells with hDSG2 knock-down by siRNA were hard to be infected by HAdV-B3/-B14/-B55, while the control siRNA group was still able to be infected by all these types of HAdVs. Finally, immunofluorescence confocal microscopy indicated visually that Cy3-conjugated HAdV-B55 viruses entered A549 cells by binding to DSG2 protein. Therefore, DSG2 is a major receptor of HAdV-B55 causing adult CAP. Our finding is important for better understanding of interactions between adenoviruses and host cells and may shed light on the development of new drugs that can interfere with these processes as well as for the development of potent prophylactic vaccines.

Cytokine/Chemokine Expression Is Closely Associated Disease Severity of Human Adenovirus Infections in Immunocompetent Adults and Predicts Disease Progression

Increasing human Adenovirus (HAdV) infections complicated with acute respiratory distress syndrome (ARDS) even fatal outcome were reported in immunocompetent adolescent and adult patients. Here, we characterized the cytokine/chemokine expression profiles of immunocompetent patients complicated with ARDS during HAdV infection and identified biomarkers for disease severity/progression. Forty-eight cytokines/chemokines in the plasma samples from 19 HAdV-infected immunocompetent adolescent and adult patients (ten complicated with ARDS) were measured and analyzed in combination with clinical indices. Immunocompetent patients with ARDS caused by severe acute respiratory disease coronavirus (SARS-CoV)-2, 2009 pandemic H1N1 (panH1N1) or bacteria were included for comparative analyses. Similar indices of disease course/progression were found in immunocompetent patients with ARDS caused by HAdV, SARS-CoV-2 or panH1N infections, whereas the HAdV-infected group showed a higher prevalence of viremia, as well as increased levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and creatine kinase (CK). Expression levels of 33 cytokines/chemokines were increased significantly in HAdV-infected patients with ARDS compared with that in healthy controls, and many of them were also significantly higher than those in SARS-CoV-2-infected and panH1N1-infected patients. Expression of interferon (IFN)-γ, interleukin (IL)-1β, hepatocyte growth factor (HGF), monokine induced by IFN-γ (MIG), IL-6, macrophage-colony stimulating factor (M-CSF), IL-10, IL-1α and IL-2Ra was significantly higher in HAdV-infected patients with ARDS than that in those without ARDS, and negatively associated with the ratio of the partial pressure of oxygen in arterial blood/fraction of inspired oxygen (PaO₂/FiO₂). Analyses of the receiver operating characteristic curve (ROC) showed that expression of IL-10, M-CSF, MIG, HGF, IL-1β, IFN-γ and IL-2Ra could predict the progression of HAdV infection, with the highest area under the curve (AUC) of 0.944 obtained for IL-10. Of note, the AUC value for the combination of IL-10, IFN-γ, and M-CSF reached 1. In conclusion, the “cytokine storm” occurred during HAdV infection in immunocompetent patients, and expression of IL-10, M-CSF, MIG, HGF, IL-1β, IFN-γ and IL-2Ra was closely associated with disease severity and could predict disease progression.

Kidney involvement in coronavirus-associated diseases (Review)

Since 2003, coronaviruses have caused multiple global pandemic diseases, including severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS) and coronavirus disease 2019 (COVID-19). Clinical and autopsy findings suggest that the occurrence of kidney injury during infection may negatively affect the clinical outcomes of infected patients. The authoritative model predicts that outbreaks of other novel coronavirus pneumonias will continue to threaten human health in the future. The aim of the present systematic review was to summarize the basic knowledge of coronavirus, coronavirus infection-associated kidney injury and the corresponding therapies, in order to provide new insights for clinicians to better understand the kidney involvement of coronavirus so that more effective therapeutic strategies can be employed against coronavirus infection in the future.

Persistent viral shedding of human adenovirus type 7 in children with severe pneumonia

To understand host-pathogen interactions and develop effective prevention and control strategies for human adenovirus (HAdV), it is essential to explore the characteristics of HAdV shedding. Hospitalized children <14 years who had severe HAdV pneumonia were tested for HAdV DNA by quantitative real-time PCR in nasopharyngeal aspirate (NPA). A total of 132 children were enrolled, including 102 patients with HAdV type 7 (HAdV-7) infection and 12 patients with HAdV type 3 (HAdV-3) infection. A total of 1372 qualified NPA samples were collected. There was a significant negative correlation between the viral load of HAdV and the course of the disease (Spearman r = -0.547, p = .000). HAdV-7 load decreased at a rate of 0.089 log10 copies/mL per day (95% CI: -0.096 to -0.081; R ² = 0.332), and the duration of viral shedding was predicted to be 96.9 days (y = 8.624-0.089x). However, HAdV-3 load decreased more quickly (95% CI: - 0.229 to - 0.143; R ² = 0.403), and the duration of viral shedding was 51.4 days (y = 9.558-0.186x). The median viral load of the HAdV-7 group at weeks 2 and 3, and more than 3 weeks postinfection was higher than that of the HAdV-3 group. No significant differences in the duration of viral shedding were found in different gender, age (>2 vs. ≤2 years), and with or without underlying diseases groups. Viral shedding in children with severe HAdV pneumonia persisted, among which HAdV-7 lasted longer than 3 months and the viral load decreased slowly than HAdV-3.

Ongoing outbreak of human adenovirus-associated acute respiratory illness in the Republic of Korea military, 2013 to 2018

BACKGROUND/AIMS

Human adenovirus type 55 (HAdV-55), an emerging epidemic strain, has caused several large outbreaks in the Korean military since 2014, and HAdV-associated acute respiratory illness (HAdV-ARI) has been continuously reported thereafter.

METHODS

To evaluate the epidemiologic characteristics of HAdV-ARI in the Korean military, we analyzed respiratory virus polymerase chain reaction (RV-PCR) results, pneumonia surveillance results, and severe HAdV cases from all 14 Korean military hospitals from January 2013 to May 2018 and compared these data with nationwide RV surveillance data for the civilian population.

RESULTS

A total of 14,630 RV-PCRs was performed at military hospitals. HAdV (45.4%) was the most frequently detected RV, followed by human rhinovirus (12.3%) and influenza virus (6.3%). The percentage of the military positive for HAdV was significantly greater than the percentage of civilians positive for HAdV throughout the study period, with a large outbreak occurring during the winter to spring of 2014 to 2015. The outbreak continued until the end of the study, and non-seasonal detections increased over time. The reported number of pneumonia patients also increased during the outbreak. Case fatality rate was 0.075% overall but 15.6% in patients with respiratory failure. The proportion of severe patients did not change significantly during the study period.

CONCLUSION

A large HAdV outbreak is currently ongoing in the Korean military, with a trend away from seasonality, and HAdV-55 is likely the predominant strain. Persistent efforts to control the outbreak, HAdV type-specific surveillance, and vaccine development are required.

Epidemiology and Genetic Variabilities of Human Adenovirus Type 55 Reveal Relative Genome Stability Across Time and Geographic Space in China

After the first outbreak in China in 2006, human adenovirus type 55 (HAdV-B55) has become a common pathogen causing life threatening pneumonia in northern China. However, HAdV-B55 infection has been rarely reported in southern China. Here, we collected throat swabs from 3,192 hospitalized children with acute respiratory disease (ARD) from May 2017 to April 2019 in Guangzhou, southern China, tested them for HAdV-B55 infection. Only one of 1,399 patients from May 2017 to April 2018 was HAdV-B55 positive; HAdV-B55 infections significantly increased with 10 of 1,792 patients testing positive since May 2018. HAdV-B55-267, isolated from a case of death, was sequenced for whole genomic analysis. Three other strains, HAdV-B55-Y16, -TY12, and -TY26, isolated earlier in patients from Shanxi, northern China, were also sequenced and analyzed. The four HAdV-B55 strains formed similar plaques, grew to similar titers, and resulted in similar typical cell pathogenic effects. HAdV-B55-267 formed a subclade with the prototype strain QS-DLL; strains HAdV-B55-Y16, -TY12, and -TY26 were closely related to strain QZ01. HAdV-B55 could be divided into two subtypes (HAdV-B55-a and -b) according to the presence or absence of the insertion of "CCATATCCGTGTT"; all strains isolated from China except for strain BJ01 belong to subtype b. HAdV-B55-267 had only one non-synonymous substitution comparing with strain QS-DLL, and all HAdV-B55 strains had highly conserved capsid proteins and few non-synonymous substitutions. This study suggests that HAdV-B55 is an important pathogen associated with ARD in Guangzhou since 2018, exhibiting the relative genome stability across time and geographic space in China.

Human adenoviruses associated with respiratory illness in neonates, infants, and children in the Sousse area of Tunisia

Background

The human Adenovirus (HAdV) is a common agent of acute respiratory infections (ARIs). Its clinical impact in immunocompetent children and in the context of coinfections remains unclear in Tunisia.

Material and methods

HAdV‐ARIs were studied in hospitalized patients from birth to the age of 5 years from 2013 to 2014. Clinical and demographic characteristics, coinfections, and molecular characterization of HAdV were established.

Results

HAdV‐positivity was detected in 114/583 specimens (19.6%) including 6.1% single infections and 93.9% coinfections. Adenoviral coinfections mostly comprised human Rhinovirus (50.9%), Streptococcus pneumoniae (34.2%), human Respiratory Syncytial virus A/B (29.8%), and human Coronaviruses (21.9%). HAdV infection was predominant in the pediatric population (25.0% vs 10.0% in neonates, P < .001) and peaked in February 2014 (21.1%). HAdV severity of pediatric cases is characterized by low saturation of oxygen (<94%, 33.8%, P = .05) and long duration of oxygen support (≥5 days, 32.7%, P = .02). Severe HAdV infections were described with S. pneumoniae coinfection, which seemed to increase the risk of death. HAdV genotyping identified HAdV‐C as the most common species. Severe ARIs were observed in all HAdV‐identified types. Phylogenetic analysis revealed that sequences were variable suggesting the circulation of different HAdV strains sharing more similarities to strains circulating in Europe or Asia than those from Africa.

Conclusion

This first molecular study of HAdV in Tunisia demonstrated that it has an important role in severe ARIs with HAdV‐C being the most common species. S. pneumoniae codetection seems to increase the severity of HAdV‐ARIs.

Epidemiology of human adenovirus associated with respiratory infection in southern Brazil

Human adenoviruses (HAdVs) are associated with respiratory infection in the human population worldwide, but HAdV is underreported and less studied than other respiratory viruses. We investigated HAdV in patients with respiratory infection in Rio Grande do Sul (RS), Brazil, between 2004 and 2018. The frequency and seasonality of HAdV, clinical symptoms and underlying diseases were analysed. Respiratory samples from outpatients with acute respiratory illness (ARI) who attended sentinel units and from inpatients with severe acute respiratory infection (SARI) were collected for HAdV detection by immunofluorescence assay; demographic and clinical data were analysed. In total, 43,514 cases of respiratory infection were analysed, of which 8,901 were ARI (20.5%), and 34,613 (79.5%) were SARI. Respiratory viruses were detected in 35.8% of the cases. The frequency of HAdV in relation to respiratory viruses was 2.8%. HAdV circulated year-round, with higher frequency during winter and early spring; increases in the average monthly temperature were associated with decreases in HAdV infections (p = 0.013). Most hospitalized patients with HAdV were male (p = 0.003). HAdV infection showed association with age (p < 0.001), and children between 1 and 5 years old accounted for 30.8% of the outpatients, whereas among cases of SARI, 88.2% were paediatric patients. Among inpatients with HAdV, 3% died, and of these, the majority had at least one underlying condition, such as cardiopathy and immunosuppression. HAdV infection of the respiratory tract causes morbidity and mortality, and individuals with heart diseases and the immunocompromised are at higher risk of fatality.

Comparison of Clinical, Laboratory and Radiological Characteristics Between COVID-19 and Adenovirus Pneumonia: A Retrospective Study

Background

The pandemic of coronavirus disease 2019 (COVID-19) has become a global public health problem. It is important for clinical physicians to differentiate COVID-19 from other respiratory infectious diseases caused by viruses, such as human adenovirus.

Subjects and Methods

This was a retrospective observational study. We analyzed and compared the clinical manifestations, laboratory findings and radiological features of two independent cohorts of patients diagnosed with either COVID-19 (n=36) or adenovirus pneumonia (n=18).

Results

COVID-19 did not show a preference in males or females, whereas 94.4% of patients with adenovirus pneumonia were males. Fever and cough were common in both COVID-19 and adenovirus pneumonia. But the median maximal body temperature of the adenovirus pneumonia cohort was significantly higher than in COVID-19 (P<0.001). Furthermore, 77.8% of patients with adenovirus pneumonia had a productive cough versus only 13.9% of COVID-19 patients (P<0.001). Compared with adenovirus pneumonia, constitutional symptoms were less common in COVID-19, including headache (16.7% vs 38.9%, P=0.072), sore throat (8.3% vs 27.8%, P=0.058), myalgia (8.3% vs 61.1%, P<0.001) and diarrhea (8.3% vs 44.4%, P=0.002). Furthermore, patients with COVID-19 were less likely to develop respiratory failure (8.3% vs 83.3%, P<0.001) and showed less prominent laboratory abnormalities, including lymphocytopenia (61.1% vs 88.9%, P=0.035), thrombocytopenia (2.8% vs 61.1%, P<0.001), elevated procalcitonin (2.8% vs 77.8%, P<0.001) and elevated C-reactive protein (36.1% vs 100%, P<0.001). Besides, a higher percentage of patients with adenovirus pneumonia showed elevated transaminase, myocardial enzymes, creatinine and D-dimer compared with COVID-19 patients. On chest CT, the COVID-19 cohort was characterized by peripherally distributed ground-glass opacity and patchy shadowing, while the adenovirus pneumonia cohort frequently presented with consolidation and pleural effusion.

Conclusion

There were many differences between patients diagnosed with COVID-19 and those with adenovirus pneumonia in their clinical, laboratory and radiological characteristics. Compared with adenovirus pneumonia, COVID-19 patients tended to show a lower severity of illness.

Human Desmoglein-2 and Human CD46 Mediate Human Adenovirus Type 55 Infection, but Human Desmoglein-2 Plays the Major Roles

Human adenovirus type 55 (HAdV55) represents an emerging respiratory pathogen and causes severe pneumonia with high fatality in humans. The cellular receptors, which are essential for understanding the infection and pathogenesis of HAdV55, remain unclear. In this study, we found that HAdV55 binding and infection were sharply reduced by disrupting the interaction of viral fiber protein with human desmoglein-2 (hDSG2) but only slightly reduced by disrupting the interaction of viral fiber protein with human CD46 (hCD46). Loss-of-function studies using soluble receptors, blocking antibodies, RNA interference, and gene knockout demonstrated that hDSG2 predominantly mediated HAdV55 infection. Nonpermissive rodent cells became susceptible to HAdV55 infection when hDSG2 or hCD46 was expressed, but hDSG2 mediated more efficient HAd55 infection than hCD46. We generated two transgenic mouse lines that constitutively express either hDSG2 or hCD46. Although nontransgenic mice were resistant to HAdV55 infection, infection with HAdV55 was significantly increased in hDSG2^+/+ mice but was much less increased in hCD46^+/+ mice. Our findings demonstrate that both hDSG2 and hCD46 are able to mediate HAdV55 infection but hDSG2 plays the major roles. The hDSG2 transgenic mouse can be used as a rodent model for evaluation of HAdV55 vaccine and therapeutics.IMPORTANCE Human adenovirus type 55 (HAdV55) has recently emerged as a highly virulent respiratory pathogen and has been linked to severe and even fatal pneumonia in immunocompetent adults. However, the cellular receptors mediating the entry of HAdV55 into host cells remain unclear, which hinders the establishment of HAdV55-infected animal models and the development of antiviral approaches. In this study, we demonstrated that human desmoglein-2 (hDSG2) plays the major roles during HAdV55 infection. Human CD46 (hCD46) could also mediate the infection of HAdV55, but the efficiency was much lower than for hDSG2. We generated two transgenic mouse lines that express either hDSG2 or hCD46, both of which enabled HAd55 infection in otherwise nontransgenic mice. hDSG2 transgenic mice enabled more efficient HAdV55 infection than hCD46 transgenic mice. Our study adds to our understanding of HAdV55 infection and provides an animal model for evaluating HAdV55 vaccines and therapeutics.

Treatment of a case presenting as critical adenoviral ARDS using Cidofovir with early combinatorial prone ventilation and ECMO

Here, we report a case of adenoviral pneumonia associated with critical ARDS treated with Cidofovir, prone ventilation and extracorporeal membrane oxygenation (ECMO). The patient responded well to therapy and recovered without further complications. Cidofovir, with early prone ventilation and ECMO support, may be a therapeutic option for patients with critical ARDS related to adenoviral pneumonia.

Seroprevalence of neutralizing antibodies against human adenovirus type 55 in the South Korean military, 2018-2019

We conducted a seroprevalence study of a large ongoing outbreak of human adenovirus type 55 (HAdV-55) among the military in South Korea. Serum samples were collected between 2018 and 2019 from military-exposed (military group) and non-exposed (non-military group) populations. The plaque reduction neutralization test (PRNT) was used to assess neutralization activity against HAdV-55. A total of 100 sera was collected from the non-military group, of which 18.8% showed HAdV-55 neutralizing antibody activity. Ninety-six sera were tested from the military group, which had significantly higher prevalence of neutralizing antibodies (56.0%, P <0.001). A significantly higher proportion of the military group had PRNT titers ≥1:1,000 than the non-military group (85.7% vs. 50.0%, P = 0.004). Among the military group, 48.9% of active-duty soldiers had PRNT titers ≥1:5,000, while none of the discharged civilians did (P = 0.007). In conclusion, Koreans were exposed to HAdV-55 in their communities, but the exposure risk was higher among people in military service.

Successful Use of Cidofovir in an Immunocompetent Child With Severe Adenoviral Sepsis

Adenovirus infection is common in childhood and is generally associated with self-limited disease. Cidofovir, a viral DNA polymerase inhibitor, is used to treat adenovirus infection in select populations but is not often recommended for immunocompetent patients because of limited antiviral activity and nephrotoxicity. Here, we report a case of fulminant adenovirus infection associated with lymphopenia and multiple organ failure requiring extracorporeal membrane oxygenation support in a previously healthy child. After 1 week of supportive therapy, the patient had persistent organ failure and continued to have adenoviremia of >560 000 copies per mL. Weekly doses of cidofovir with concurrent probenecid for renal protection was initiated. Adenovirus blood load declined after the first cidofovir dose, becoming undetectable after 3 doses. The patient was successfully decannulated from extracorporeal membrane oxygenation, extubated, and eventually discharged at his functional baseline without need for ongoing respiratory support. Lymphopenia improved after viremia resolved, and a subsequent immunologic workup revealed no evidence of primary immunodeficiency. The viral isolate was genotyped as adenovirus type 7. This case reveals the successful use of cidofovir for management of severe adenovirus infection in a previously healthy child. To date, there are no universally accepted recommendations for the use of cidofovir in this population. Further study is warranted to determine the potential role of cidofovir in treating severe adenovirus infections in immunocompetent children.

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.

The spectrum of viral pathogens in children with severe acute lower respiratory tract infection: A 3-year prospective study in the pediatric intensive care unit

Background

No comprehensive analysis is available on the viral etiology and clinical characterization among children with severe acute lower respiratory tract infection (SALRTI) in Southern China.

Methods

Cohort of 659 hospitalized children (2 months to 14 years) with SALRTI admitted to the Pediatric Intensive Care Unit (PICU) in the Guangzhou from May 2015 to April 2018 was enrolled in this study. Nasopharyngeal aspirate specimens or induced sputum were tested for eight categories respiratory viral targets. The viral distribution and its clinical characters were statistically analyzed.

Results

Viral pathogen was detected in 326 (49.5%) of children with SALRTI and there were 36 (5.5%) viral coinfections. Overall, the groups of viruses identified were, in descending order of prevalence: Influenza virus (IFV) (n = 94, 14.3%), respiratory syncytial virus (RSV) (n = 75, 11.4%), human rhinovirus (HRV) (n = 56, 8.5%), adenovirus (ADV) (n = 55, 8.3%), parainfluenza (PIV) (n = 47, 7.1%), human coronavirus (HCoV) (n = 15, 2.3%), human metapneumovirus (HMPV) (n = 14, 2.1%) and human bocavirus (HBoV) (n = 11, 1.7%). The positive rate in younger children (< 5 years) was significantly higher than the positive rate detected in elder children (> 5 years) (52.5% vs 35.1%, P = 0.001). There were clear seasonal peaks for IFV, RSV, HRV, ADV, PIV, and HMPV. And the individuals with different viral infection varied significantly in terms of clinical profiles.

Conclusions

Viral infections are present in a consistent proportion of patients admitted to the PICU. IFV, RSV, HRV, and ADV accounted for more than two‐thirds of all viral SALRTI. Our findings could help the prediction, prevention and potential therapeutic approaches of SALRTI in children.

Viral infections are present in a consistent proportion of patients admitted to the Pediatric Intensive Care Unit.

Influenza virus, respiratory syncytial virus, human rhinovirus and adenovirus accounted for more than two‐thirds of all viral SALRTI.

Severe acute respiratory distress syndrome (ARDS) induced by human adenovirus B21: Report on 2 cases and literature review

Severe pneumonia and ARDS caused by human adenovirus B21 infections (HAdV-B21) is a rare, but a devastating disease with rapid progression to multiorgan failure and death. However, only a few cases were reported so far. Infections appear associated with increased disease severity and higher mortality in infected critically ill patients. Possible factors contributing to infection are underlying psychiatric disease resulting in institutionalization of respective patients, and polytoxicomania. Controlled data on the therapy of severe adenovirus infections are lacking and remains experimental. In conclusion, data on HAdV-B21 infections causing severe pneumonia or ARDS are scarce. Controlled clinical trials on the therapy of adenovirus pneumonia are non existent and thus there is no established therapy so far. ICU physicians should be aware of this potentially devastating disease and further studies are needed.

Transcriptome Sequencing Identifies Novel Immune Response Genes Highly Related to the Severity of Human Adenovirus Type 55 Infection

Human adenovirus type 55 (HAdV-55) is considered a highly virulent pathogen causing severe and even deadly pneumonia in immunocompetent people. The mechanisms of HAdV-55-induced initiation and progression of severe pneumonia remain ambiguous. In the current study, we endeavored to identify novel immune response genes which are substantially involved in the pathogenesis of severe inflammation in HAdV-55-infected patients. HAdV-55-infected patients with upper respiratory tract symptoms (minor patients) and pneumonia (severe patients) were enrolled. Through transcriptome sequencing and quantitative real-time PCR, the peripheral blood mononuclear cells of the patients were analyzed. We found that the expression of eight genes, including Il18, Il36b, Il17rc, Tnfsf10, Tnfsf11, Tnfsf14, Tnfsf15, and Il1a, were closely correlated with the severity of HAdV-55 infection. Most of these genes belong to interleukin-1 family or tumor necrosis factor (TNF) superfamily, respectively. The changes in gene expression were confirmed by Western blot assay. Our data will be crucial for deepening the understanding of the pathogenic mechanisms of severe pneumonia in HAdV-55 infection.

Prolonged shedding of type 55 human adenovirus in immunocompetent adults with adenoviral respiratory infections

Human adenovirus (HAdV) is a common pathogen causing respiratory infections with outbreaks reported in the military and community. However, little information is available on the shedding kinetics. We performed a prospective study of immunocompetent adults confirmed with HAdV respiratory infection by multiplex real-time PCR during an outbreak of HAdV-55. Consecutive respiratory specimens of sputum or nasopharyngeal swab were collected from each patient every 2 days. Viral load was measured by real-time quantitative PCR. Of 32 enrolled patients, 27 (84.4%) had pneumonia. Five patients (15.6%) received cidofovir. Viral load was highest in the earliest samples at 8.69 log₁₀ copies/mL. In a linear regression model, viral load declined consistently in a log-linear fashion at the rate of - 0.15 log₁₀ copies/mL per day (95% confidence interval (CI): - 0.18, - 0.12; R² = 0.32). However, the regression model estimated the viral shedding duration to be 55 days. The rate of decline in viral load did not differ between patients who received cidofovir and who did not. Patients with prominent respiratory symptoms or extensive involvement on chest radiograph had higher volume of viral excretion. Prolonged viral shedding was observed in otherwise healthy adults with HAdV-55 respiratory infection. This finding should be considered in the establishment of infection control and prevention strategies.

Emergence and re-emergence of respiratory adenoviruses in the United States

Human adenoviruses (HAdVs) are prevalent causes of acute respiratory disease (ARD) in military and civilian communities. Over the last 20 years, collaborative efforts between US public health, military and academic laboratories have gathered comprehensive data documenting the emergence and re-emergence of specific HAdV types in association with outbreaks and unrelated cases of ARD, which have attracted national attention. New or reemerging HAdVs have included genomic variants of HAdV-B14, HAdV-B7, and HAdV-E4. Detailed molecular characterizations of virus strains are essential to understand the etiology and epidemiology of HAdV infections. The continuation of such studies is important for ongoing assessment of the national and global evolution of respiratory HAdVs and to inform decisions regarding antiviral drug and vaccine development and implementation.

Case-control study of the epidemiological and clinical features of human adenovirus 55 and human adenovirus 7 infection in children with acute lower respiratory tract infections in Beijing, China, 2008-2013

Background

In adults, the emerging human adenovirus (HAdV) type 55 (HAdV-55) has been reported to cause more severe cases of adenovirus induced acute lower respiratory tract infections (ALRTIs) compared to other HAdV serotypes (HAdV-3, HAdV-7, HAdV-14). However, there is a dearth of comparative studies in children that address differences in the clinical epidemiological features between HAdV-55 and other HAdV serotypes that can also induce severe infection (such as HAdV-7).

Methods

We conducted a retrospective review of pediatric patients hospitalized at Beijing Children’s Hospital with ALRTI from April 2008 to December 2013 who had adenovirus detected from nasopharyngeal or throat samples by PCR. We further compared pediatric patients infected with HAdV-55 to those infected with HAdV-7 using a case-control methodology by matching each subject with HAdV-55 infection to 4 patients with HAdV-7 infection within 2 months of each HAdV-55 infection. Demographic, clinical, and etiological data were collected and analyzed.

Results

Over the five-year period, HAdV was detected in 194 children. Of these, 8 were HAdV-55 positive. Epidemiological results showed that HAdV-55 infection was observed only in 4% of adenovirus infected children whereas HAdV-7 infection proportioned 53%. Most cases of HAdV-55 infection were identified during March and April, whereas HAdV-7 infection occurred throughout the year. Wheezing was significantly less frequent in the HAdV-55 group. No patients infected with HAdV-55 presented with vomiting or had any underlying disease. Coinfections with other respiratory tract pathogens were frequent among children infected with either HAdV-55 or HAdV-7.

Conclusions

HAdV-55 circulated in Beijing during spring and appeared to cause pediatric respiratory infections that were as severe as HAdV-7 infections. Broader surveillance studies are needed.

Vaccine development for human mastadenovirus

Human mastadenovirus (HAdVs) can cause a broad spectrum of diseases in both children and adults, including acute respiratory infection, gastroenteritis, epidemic keratoconjunctivitis. Populations susceptible to adenovirus infection include children, immunocompromised patients and military recruits. To date, seven species (A-G) including more than 79 genotypes have been characterized, of which HAdV-B3, B4, B7 and the recently reemerged types 14 and 55 often lead to severe pneumonia. The live oral enteric-coated adenovirus type 4 and 7 vaccine, which was approved for use in US military personnel of 17 through 50 years of age, had been shown to be safe and highly effective in numerous clinical trials and by ongoing surveillance of febrile respiratory illness. However, there is currently no vaccine approved for general use in children and adults in any part of the world. This review article will summarize the epidemiological data available for adenovirus and the effectiveness of the adenovirus vaccine in the US military. It will also provide a brief overview of innovative vaccine strategies, animal models for vaccine evaluation, and issues regarding vaccine production.

Real-time Utilization of Metagenomic Sequencing in the Diagnosis and Treatment Monitoring of an Invasive Adenovirus B55 Infection and Subsequent Herpes Simplex Virus Encephalitis in an Immunocompetent Young Adult

Background

Metagenomic sequencing has shown tremendous promise in solving difficult infectious diseases cases. In this study, we utilized this technology to help guide the care of a critically ill patient with severe pneumonia, fever of unknown origin, and subsequent encephalitis in the intensive care unit (ICU).

Methods

Shotgun metagenomic sequencing was performed on the patient's blood, bronchoalveolar lavage (BAL), and cerebral spinal fluid by using an Illumina MiniSeq sequencer.

Results 

A high load of human adenovirus B55 (HAdV-B55), a highly pathogenic adenovirus associated with numerous recently reported outbreaks and deaths in China, was detected in both blood and BAL, which explained the severity of the condition. The patient was treated with intravenous ribavirin, which cleared the virus after 26 days. Metagenomic sequencing also helped diagnose an unexpected herpes simplex virus-1 encephalitis during hospitalization, which led to timely treatment.

Conclusions 

This was the first successful case utilizing metagenomic sequencing to guide diagnosis and treatment in the ICU setting in China. We have proven the concept that metagenomic sequencing can play an important role in determining clinical approaches and ultimately in improving patient outcomes. We also hope to share our successful treatment protocol for the severe pneumonia and viremia caused by HAdV-B55.

Hexon and fiber of adenovirus type 14 and 55 are major targets of neutralizing antibody but only fiber-specific antibody contributes to cross-neutralizing activity

Re-emerging human adenoviruses type 14 (HAdV14) and 55 (HAdV55) represent two highly virulent adenoviruses. The neutralizing antibody (nAb) responses elicited by infection or immunization remain largely unknown. Herein, we generated hexon-chimeric HAdV14 viruses harboring each single or entire hexon hyper-variable-regions (HVR) from HAdV55, and determined the neutralizing epitopes of human and mouse nAbs. In human sera, hexon-targeting nAbs are type-specific and mainly recognize HVR2, 5, and 7. Fiber-targeting nAbs are only detectable in sera cross-neutralizing HAdV14 and HAdV55 and contribute substantially to cross-neutralization. Penton-binding antibodies, however, show no significant neutralizing activities. In mice immunized with HAdV14 or HAdV55, a single immunization mainly elicited hexon-specific nAbs, which recognized HAdV14 HVR1, 2, and 7 and HAdV55 HVR1 and 2, respectively. After a booster immunization, cross-neutralizing fiber-specific nAbs became detectable. These results indicated that hexon elicits type-specific nAbs whereas fiber induces cross-neutralizing nAbs to HAdV14 and HAdV55, which are of significance in vaccine development.

A recombinant trivalent vaccine candidate against human adenovirus types 3, 7, and 55

Human adenoviruses types 3 (HAdV-3), 7 (HAdV-7) and 55 (HAdV-55) are major pathogens of acute respiratory infections (ARI) in children and adults. More than one type of HAdV can infect patients simultaneously, and the infections are sometimes fatal. However, there is currently no vaccine approved for general use in children and adults. Thus, development of a multivalent HAdV vaccine to combat HAdV infection becomes imperative. In this study, we constructed a new recombinant trivalent human adenovirus vaccine (rAdMHE3-h55), which expresses the hexon protein of HAdV-55 in the E3 region of rAdMHE3, a previously prepared bivalent vaccine candidate against HAdV-3 and HAdV-7. The results of in vitro neutralization assays indicate that rAdMHE3-h55 can induce the production of neutralizing antibodies against HAdV-3, HAdV-7, and HAdV-55 in mice. Furthermore, immunization with the recombinant trivalent vaccine candidate completely protected the mice challenged with HAdV-3, HAdV-7, orHAdV-55, respectively, showing lower lung viral loads and less lung Pathological changes was compared with those in unvaccinated mice. The current findings contribute to the development of a new adenovirus vaccine candidate and also advance this construction method for the generation of recombinant adenovirus vaccines. In conclusion, our recombinant trivalent vaccine rAdMHE3-h55 can provides protection against challenge with HAdV-3, HAdV-7, or HAdV-55 in mice. Future work of optimizing this vaccine candidate may lead to a more effective way of preventing respiratory diseases caused by common human adenoviruses.

The Repertoire of Adenovirus in Human Disease: The Innocuous to the Deadly

Adenoviridae is a family of double-stranded DNA viruses that are a significant cause of upper respiratory tract infections in children and adults. Less commonly, the adenovirus family can cause a variety of gastrointestinal, ophthalmologic, genitourinary, and neurologic diseases. Most adenovirus infections are self-limited in the immunocompetent host and are treated with supportive measures. Fatal infections can occur in immunocompromised patients and less frequently in the healthy. Adenoviral vectors are being studied for novel biomedical applications including gene therapy and immunization. In this review we will focus on the spectrum of adenoviral infections in humans.

Comparison of the prevalence of respiratory viruses in patients with acute respiratory infections at different hospital settings in North China, 2012-2015

BACKGROUND

Acute respiratory infections (ARIs) are a great public health challenge globally. The prevalence of respiratory viruses in patients with ARIs attending at different hospital settings is fully undetermined.

METHODS

Laboratory-based surveillance for ARIs was conducted at inpatient and outpatient settings of 11 hospitals in North China. The first 2-5 patients with ARIs were recruited in each hospital weekly from 2012 through 2015. The presence of respiratory viruses was screened by PCR assays. The prevalence of respiratory viruses was determined and compared between patients at different hospital settings.

RESULTS

A total of 3487 hospitalized cases and 6437 outpatients/Emergency Department (ED) patients were enrolled. The most commonly detected viruses in the hospitalized cases were respiratory syncytial virus (RSV, 33.3%) in children less than two years old, adenoviruses (13.0%) in patients 15-34 years old, and influenza viruses (IFVs, 9.6%) in patients ≥65 years. IFVs were the most common virus in outpatient/ED patients across all age groups (22.7%). After controlling for the confounders caused by other viruses and covariates, adenoviruses (adjusted odds ratio [aOR]: 3.97, 99% confidence interval [99% CI]: 2.19-7.20) and RSV (aOR: 2.04, 99% CI: 1.34-3.11) were independently associated with increased hospitalization in children, as well as adenoviruses in adults (aOR: 2.14, 99% CI: 1.19-3.85). Additionally, co-infection of RSV with IFVs was associated with increased hospitalization in children (aOR: 12.20, 99% CI: 2.65-56.18).

CONCLUSIONS

A substantial proportion of ARIs was associated with respiratory viruses in North China. RSV, adenoviruses, and co-infection of RSV and IFVs were more frequent in hospitalized children (or adenoviruses in adults), which might predict the severity of ARIs. Attending clinicians should be more vigilant of these infections.

Whole-genome analyses of human adenovirus type 55 emerged in Tibet, Sichuan and Yunnan in China, in 2016

Three outbreaks of acute respiratory disease occurred at military camps in 2016 at Tibet, Sichuan and Yunnan province, China. The pathogen induced these three outbreaks were all confirmed as HAdV-55 by genotype-specific PCR. The outbreak in Tibet was the first report that HAdV-55 occurred in the high altitude (HA, above sea level 3658 m). This study aims to determine the gene variation and evolution characteristics of these viral strains. Three strains of adenoviruses, LS89/Tibet/2016 (GenBank accession no. KY002683), SF04/SC/2016 (GenBank accession no. KY002684) and KM03/YN/2016 (GenBank accession no. KY002685) were obtained and confirmed by wholegenome sequencing. No multi-gene fragments recombination were found in these isolated HAdV-55 virus compared with previous reported HAdV-55 strains in China. The outbreaks in Tibet and in Sichuan continuously occurred. Virus isolated from Tibet (LS89/Tibet/2016) and Sichuan (SF04/SC/2016) had a similar mutation pattern and had a closer genetic evolutionary distance than KM03/YN/2016 strain, which indicates that the pathogens causing these two outbreaks may be of the same origin. Moreover, we found that heating was an effective way to inactive these viruses, which provide valuable information for the development of HAdV-55 vaccines. Our data provide new information for genetic evolution of HAdV-55, and contribute to the prevention and control of HAdV-55 infection in the future.

Diagnosis and treatment of community-acquired pneumonia in adults: 2016 clinical practice guidelines by the Chinese Thoracic Society, Chinese Medical Association

Community‐acquired pneumonia (CAP) in adults is an infectious disease with high morbidity in China and the rest of the world. With the changing pattern in the etiological profile of CAP and advances in medical techniques in diagnosis and treatment over time, Chinese Thoracic Society of Chinese Medical Association updated its CAP guideline in 2016 to address the standard management of CAP in Chinese adults. Extensive and comprehensive literature search was made to collect the data and evidence for experts to review and evaluate the level of evidence. Corresponding recommendations are provided appropriately based on the level of evidence. This updated guideline covers comprehensive topics on CAP, including aetiology, antimicrobial resistance profile, diagnosis, empirical and targeted treatments, adjunctive and supportive therapies, as well as prophylaxis. The recommendations may help clinicians manage CAP patients more effectively and efficiently. CAP in pediatric patients and immunocompromised adults is beyond the scope of this guideline. This guideline is only applicable for the immunocompetent CAP patients aged 18 years and older. The recommendations on selection of antimicrobial agents and the dosing regimens are not mandatory. The clinicians are recommended to prescribe and adjust antimicrobial therapies primarily based on their local etiological profile and results of susceptibility testing, with reference to this guideline.

A cluster of adenovirus type B55 infection in a neurosurgical inpatient department of a general hospital in Guangdong, China

BACKGROUND

Human adenovirus type 55 is a re-emerging human respiratory pathogen that is associated with several respiratory infections outbreaks in military and school populations. In this study, we describe the first HAdV55-associated hospital outbreak documented in Guangdong, China.

METHODS

Active surveillance was conducted in the involved neurosurgical inpatient department. All staff and patients in the involved neurosurgical department were surveyed for any symptoms of fever (≥38°C) and enlarged tonsils during the outbreak period. Throat swabs and demographic information were collected for all cases. For each specimen, assays for common respiratory viruses were performed using one-step reverse transcription-polymerase chain reaction. HAdV-positive samples were inoculated onto Hep-2 cells for isolation. Hexon genes, fiber genes, penton genes, and whole genomes were sequenced. A phylogenetic tree was constructed.

RESULTS AND CONCLUSIONS

Forty-three cases, including 24 laboratory-confirmed cases and 19 possible cases, were identified. Nurses had the highest attack rate of infection, with a rate of 36.4%. The attack rate for doctors and inpatients was 20.0% and 16.7%, respectively. HAdV55 was the sole pathogen identified during this outbreak. The hexon, fiber, and penton genes from seven isolated HAdV55 stains were sequenced. All these genes showed 100% homology and fell into the HAdV55 [P14H11F14] cluster, indicating that HAdV55 was the single viral strain for the outbreak. While not conclusive, the epidemic investigation revealed that the outbreak was introduced by nurses from sources outside the hospital. It was likely that a transmission from staff to inpatients had occurred.

Clinical features of community acquired adenovirus pneumonia during the 2011 community outbreak in Southern Taiwan: role of host immune response

Background

Human adenovirus 7 (HAdV-7) was responsible for a significant number of fatalities during the 2011 community outbreak in Taiwan. The mechanisms underlying the pathogenesis of severe adenovirus infections in non-immunocompromised individuals remain unclear. Adenovirus pneumonia was associated with pleural effusion in a number of patients from the 2011 outbreak suggesting that similar to bacterial pneumonia, patients diagnosed with adenovirus pneumonia who have pleural effusion are more severely and systemically infected, and may have a more protracted disease course. We hypothesized that the host immunological response determines the severity of adenoviral infection.

Methods

This retrospective case series study included patients diagnosed with severe lower respiratory tract infections at the National Cheng Kung University Hospital in southern Taiwan between December 2010 and October 2011. The main inclusion criteria were 1) presence of multifocal patchy infiltrates, lobar consolidation or reticular interstitial opacities in chest X-rays, and 2) presence of adenovirus isolated from respiratory specimens. All patients had adenovirus isolated from respiratory specimens, and were negative for other viruses. Pleural effusion was confirmed in all patients using chest echography. Clinical features and laboratory data were compared in patients with (n = 12) and without (n = 15) parapneumonic effusion.

Results

Presence of parapneumonic effusion was significantly associated with a longer febrile duration, more complicated clinical management, and a greater risk of extrapulmonary involvement, notably hepatitis. Patients without pleural effusion had significantly higher numbers of WBCs, platelets, and absolute segment cell counts (ASCs) compared to patients with pleural effusion (all p < 0.05). Patients without pleural effusion had significantly higher counts of CD4+, CD8+, and CD20+ T cells (all p < 0.05) compared to patients with pleural effusion.

Conclusion

Our data indicated that presence of parapneumonic effusion in adenoviral pneumonia was associated with longer febrile duration, more complicated clinical management, a greater risk of hepatitis, and suppression of host cellular immunity. Further prospective, large-scale studies are needed to validate our results.