Adenovirus serotype 3 and 7 infection with acute respiratory failure in children in Taiwan, 2010-2011

Clinical features and risk factors of adenovirus-related plastic bronchitis in children

BACKGROUND

To analyze the clinical characteristics of children with adenoviral pneumonia, identify independent risk factors for early prediction of plastic bronchiolitis (PB), and develop a predictive nomogram.

METHODS

This retrospective study analyzed the clinical data of children diagnosed with adenoviral pneumonia. Patients were categorized into PB and non-PB groups. General characteristics, clinical symptoms, laboratory findings, and imaging results were compared between the two groups. Multivariate logistic regression was used to identify significant risk factors, and a nomogram model was constructed.

RESULTS

Among the 164 patients, 139 were in the non-PB group and 25 were in the PB group. Multivariate logistic regression identified diminished breath sounds, D-dimer (D-D) levels, and Lactic dehydrogenase (LDH) levels as significant risk factors for PB. The nomogram developed from these factors had an area under the receiver operating characteristic curve (AUC) of 0.904 (95% confidence interval: 0.847-0.960). The Hosmer-Lemeshow test showed good calibration (p = 0.515, X2 = 7.207).

CONCLUSIONS

Diminished breath sounds, D-D levels, and LDH levels are independent risk factors for PB in children with adenoviral pneumonia. The developed nomogram demonstrates high predictive accuracy and good calibration, providing a valuable tool for early prediction and clinical decision-making. Future studies should validate this nomogram in larger and diverse populations.

Clinical Characteristics and Severity Predictors of Pediatric Adenovirus Infections

Adenovirus infections impose a significant disease burden on children and can result in poor clinical outcomes, thus requiring intensive care and potentially leading to fatality. We retrospectively analyzed pediatric adenovirus cases from 2018 to 2023 at a children's hospital in Taiwan and collected data regarding patients' clinical symptoms, imaging results, and laboratory findings. Multiple logistic regression was used to identify predictors of severe cases requiring intensive care. Our study revealed that adenovirus cases were more common in the winter, with a post-COVID-19 surge observed in 2023. A total of 576 pediatric adenovirus cases were collected, including 27 (4.7%) severe cases and 3 (0.5%) fatal cases. Severe cases were younger and exhibited higher frequencies of dyspnea, decreased activity, and diagnoses of bronchopneumonia/pneumonia and genetic disorders. Compared with nonsevere cases, severe cases also demonstrated more patchy opacity, lobar consolidation, pleural effusion, and bacterial coinfection. Multivariable analysis revealed that the most significant predictors of severe cases were dyspnea (aOR 18.5 [95% CI 3.792-90.257]), patchy opacity (3.391 [1.150-9.994]), lobar consolidation (116.388 [8.555-1583.393]), pleural effusion (9.117 [0.917-90.630]), and invasive bacterial coinfection (60.469 [4.047-903.555]), which are newly recognized predictors, thus highlighting the need for increased clinical vigilance.

Increased Trend of Adenovirus Activity After the COVID-19 Pandemic in South Korea: Analysis of National Surveillance Data

The adenovirus detection rate is <10% throughout the year in South Korea; however, during the summer of 2023, it showed an unusual increase. We analyzed the adenovirus detection rate using data from the Korea Respiratory Integrated Surveillance System before and after coronavirus disease (COVID-19) collected from 2019 to week 36 of 2023. Before the COVID-19 outbreak in 2019, the mean detection rate was 8.2%, which decreased to 6.1% during the COVID-19 pandemic from 2020 to 2022. In 2023, the mean detection rate was 14.3% in week 36 and the highest in week 34, at 42.2%, and adenovirus was predominantly detected in the summer. The detection rate by age group showed substantially high activity among 0-12-yr-olds after the pandemic. This age group had a steady mean rate of 9.5% during the pandemic, without seasonality. In 2023, the detection rate surged in the 0-6-yr and 7-12-yr age groups, peaking at 61.6% and 57.1%, respectively. The dominant epidemic serotypes were HAdV-1 and HAdV-2 during and HAdV-3 after the pandemic. The multifaceted non-pharmaceutical interventions during the COVID-19 pandemic considerably impacted the prevalence of common respiratory viruses and complicated respiratory virus patterns after the pandemic. Constant surveillance is crucial for epidemic preparedness to monitor the possible surge of certain respiratory viruses.

Mutated Adenovirus Attacks in West Bengal, India: Risk Evaluation of Multi-Country Outbreaks and Mitigation Strategies

AIM

The human adenovirus (HAdV) is beginning to spread rapidly in children through human, surface and animal vectors. Around 12,000 cases were recognised in 2022 in West Bengal and a shocking number of cases arose throughout India and in other under-developed areas. This is going to be a big threat to public health since no vaccine, awareness or protocol policies were introduced. Early detection, immediate isolation and proper policy developments are the key factors in overcoming the situation. Therefore, we performed this rapid review and discussed probable mitigation strategies, updated research on vaccine development, and treatment strategies to control the outbreaks of mutated HAdV.

DESIGN

This is a narrative review of publicly available information.

METHODS

Here, we extracted updated information and data using the terms HAdV outbreaks, mutations, species, risks and prevention from Google Scholar and PubMed. We considered relevant articles that have discussed prevention strategies, ongoing research, and antiviral drugs for managing HAdV outbreaks.

RESULTS

Early detection from throat swabs, isolation and symptomatic treatments are required to minimise viral infections. A massive test needs to be performed to find the affected people. The cases should be immediately isolated. It is recommended to treat high-touch surfaces with heat- or bleach-containing cleaners to prevent the spread of infection. Oxygen support and many broad-spectrum antivirals have been used to treat HAdV. Several studies showed antibody neutralisation and interactions between the natural killer cell receptor KIR3DS1 and HLA-F in infected cells, indicating possible therapeutic options in the future. HAdV-4 and HAdV-7 vaccines have been limitedly approved for administration to military personnel.

CONCLUSION

Isolation, certain safety measures, broad-spectrum antiviral drugs and further research on new vaccines could be useful to prevent this virus from producing a worldwide pandemic. Also, the authorities should ensure the proper therapeutic interventions and nursing care facilities for the infected children.

PATIENT OR PUBLIC CONTRIBUTION

Patient or public contribution was not relevant to our work.

Clinical epidemiology of adenovirus pneumonia among Chinese hospitalized children

Adenovirus pneumonia is a prevalent form of community-acquired pneumonia among children. Research on the epidemiology and economic burden of this disease is crucial for public health, yet comprehensive data remains scarce, making it crucial to highlight on this topic. In this study, the data were extracted from the face sheet of discharge medical records collected from 26 tertiary children's hospitals from January 2016 to December 2021. In total, 1854 children with laboratory-confirmed adenovirus pneumonia were hospitalized, accounting for 0.13% of the total number of hospitalized for pneumonia in the database during the period. In addition, this figure represents a meager 0.027% when compared to the total number of hospitalized children. The male-to-female ratio was 1.78:1. The 1-3-year age group had the highest number of inpatients for adenoviral pneumonia and the largest proportion of the total hospitalizations in the same age group. Overall, winter is the primary season for the prevalence of adenovirus pneumonia, however, in southern China, there are two peak seasons, winter and summer. Although patients with 3/4 adenovirus pneumonia had no significant complications, some patients had complications such as respiratory failure, diarrhea, and myocardial damage. The median length of stay of adenovirus pneumonia was 8 d [interquartile range (IQR) 6-11], and the median hospitalization cost was 1293.83 United States dollars (IQR 811.81-2472.51). These valuable epidemiological insights into adenovirus pneumonia in Chinese children can help direct the development of targeted prevention and control strategies and surveillance measures for HAdV infections in this demographic.

Evaluation of Risk Factors for Children with Severe Adenovirus Respiratory Infection: Retrospective Study

Background: Human adenovirus (HAdV) commonly affects children hospitalized with any form of respiratory infection (RI). Severe HAdV infection leads to one of the most serious types of infantile RI, with rapidly progressive illness and a poor prognosis. Objectives: This study investigated the relationship between aspartate aminotransferase (AST) levels and the severity of HAdV RI in children. Methods: We collected clinical data from 665 cases of HAdV RI in children hospitalized at the pediatric ward of Changde First People's Hospital between January and December 2019. We analyzed the relationship between AST levels and disease severity. Results: Of the 665 HAdV-positive cases, 89.8% were < 6 years of age. Among them, upper RI was diagnosed in 18.8% of cases, bronchiolitis in 4.8%, and mild pneumonia in 48.1%. Severe pneumonia was observed in 28.2% of cases. The 665 patients in the cohort were divided into a mild group (n = 477 cases, 71.73%) and a severe group (n = 188 cases, 28.27%). Univariate analysis showed that children with severe HAdV RI had a lower age of onset and lower hemoglobin and serum albumin levels while having higher platelet counts, lactic acid dehydrogenase, creatine kinase, creatine kinase isoenzyme, alanine aminotransferase, and AST levels compared to those with mild infections (P < 0.05). Multivariate analysis revealed that these factors were related to disease severity (P < 0.05). The ROC curve analysis indicated that the area under the AST curve was 0.782. When the intercept value was 52.5 U/L, the sensitivity was 60.6%, and the specificity was 83.4%. Conclusions: Serum AST levels can serve as a predictor of adenoviral RI severity in children.

Adenovirus and Mycoplasma pneumoniae co-infection as a risk factor for severe community-acquired pneumonia in children

Background

To investigate the pathogenic characteristics and risk factors of pediatric severe community-acquired pneumonia (CAP).

Methods

We retrospectively analyzed the clinical data of hospitalized children with severe CAP from April 2014 to June 2019 in China. Data of age, sex and pathogenic results were collected: bacterial and fungal cultures, respiratory viruses from sputum or bronchoalveolar lavage fluid (BALF), serum Mycoplasma pneumoniae (MP)-IgM and Chlamydia Pneumoniae-IgM, and BALF or blood (1-3)-β-D-glucan/galactomannan test.

Results

A total of 679 children with severe CAP were included in the analysis. The number of cases infected with MP was higher in males than in females. There were significant differences between the ≤1-year and >1-year groups in terms of pathogen. The top three bacteria cultured were Haemophilus influenzae (57/679, 8.4%), Streptococcus pneumoniae (50/679, 7.4%), and Pseudomonas aeruginosa (25/679, 3.7%). The top three viruses detected were adenovirus (AdV, 124/679, 18.3%), respiratory syncytial virus (24/679, 3.5%), and parainfluenza virus (21/679, 3.1%). AdV and MP were the leading pathogens, detected in 18.3% and 32.6% cases, respectively. MP infection increased the risk of AdV infection (OR 3.77, p < 0.0001). MP infection was a risk factor for severe AdV-infected pneumonia, while sex, age, bacteria, Chlamydia Pneumoniae, fungal, and AdV infections were risk factors for severe MP-infected pneumonia.

Conclusions

AdV and MP were dominant pathogens in children with severe CAP. AdV and MP infection predisposed each other to develop severe illness. AdV-MP co-infection may lead to severe pneumonia.

Higher affinities of fibers with cell receptors increase the infection capacity and virulence of human adenovirus type 7 and type 55 compared to type 3

IMPORTANCE

HAdV-3, -7, and -55 are the predominant types causing acute respiratory disease outbreaks and can lead to severe and fatal pneumonia in children and adults. In recent years, emerging or re-emerging strains of HAdV-7 and HAdV-55 have caused multiple outbreaks globally in both civilian and military populations, drawing increased attention. Clinical studies have reported that HAdV-7 and HAdV-55 cause more severe pneumonia than HAdV-3. This study aimed to investigate the mechanisms explaining the higher severity of HAdV-7 and HAdV-55 infection compared to HAdV-3 infection. Our findings provided evidence linking the receptor-binding protein fiber to stronger infectivity of the strains mentioned above by comparing several fiber-chimeric or fiber-replaced adenoviruses. Our study improves our understanding of adenovirus infection and highlights potential implications, including in novel vector and vaccine development.

Molecular epidemiology of circulating human adenoviruses among acute respiratory infection patients seeking healthcare facilities in West Bengal, India

Human adenovirus (HAdV) causes acute respiratory infections leading to mortality in children. This study analyzes the circulating respiratory HAdV genotypes in West Bengal, India during 2018-2022 among symptomatic patients. The overall positivity rate was 6.8%, out of which 26.4% were co-infected with other respiratory viruses. Children aged 2 to 5 years were mostly infected. Phylogenetic analysis revealed that the recombinant HAdV-B type 7/3, which has remarkable outbreak potential, predominantly circulated in this region followed by the non-recombinant HAdV-B type 3/3. Moreover, the amino acid sequences encoded by both the hexon and fiber genes of these two circulating strains possessed a few mutations that mostly diverged from the prototype strain, although the divergence was less pronounced in case of the amino acids encoded by the fiber gene of HAdV-B type 3/3. Overall, the results underscore the need for continuous surveillance of respiratory HAdV types to combat future possible epidemics.

Seroprevalence of neutralizing antibodies to human mastadenovirus serotypes 3 and 7 in healthy children from guangdong province

Severe adenovirus pneumonia is becoming more common in children infected with human mastadenovirus (HAdV)-3 and HAdV-7 than in those infected with other types of adenoviruses. Recently, there has been a trend toward an increasing prevalence of pneumonia caused by HAdV-7, an important viral pathogen in Pediatric Intensive Care Unit infections. Children infected with HAdV-7 have more serious symptoms of acute respiratory infections and other complications than those infected with HAdV-3. No specific anti-adenovirus drugs or vaccines are available for treatment or prevention. Therefore, we investigated the seroprevalence and titer levels of neutralizing antibodies (NAbs) against HAdV-3 and HAdV-7 in healthy children in Guangdong Province. We found that the seropositivity rates and antibody titers for HAdV-3 NAb were higher than those for HAdV-7 NAb. In children between 6 and 12 months of age, the seropositivity rates and titers were significantly low against HAdV-3 and HAdV-7. The HAdV-7-positive rate was significantly higher in the HAdV-3-positive samples than in the HAdV-3-negative samples. The HAdV-7 NAbs carried by the 0-6-month age group were dominated by low titers. These results reveal a low level of herd immunity against HAdV-3 and HAdV-7 in children, clarifying the importance of monitoring these two highly virulent adenoviruses, developing prophylactic vaccines, and predicting potential outbreaks.

Human adenovirus infection induces pulmonary inflammatory damage by triggering noncanonical inflammasomes activation and macrophage pyroptosis

Introduction

Human adenovirus (HAdV) is a common respiratory virus, which can lead to severe pneumonia in children and immunocompromised persons, and canonical inflammasomes are reported to be involved in anti-HAdV defense. However, whether HAdV induced noncanonical inflammasome activation has not been explored. This study aims to explore the broad roles of noncanonical inflammasomes during HAdV infection to investigate the regulatory mechanism of HAdV-induced pulmonary inflammatory damage.

Methods

We mined available data on GEO database and collected clinical samples from adenovirus pneumonia pediatric patients to investigate the expression of noncanonical inflammasome and its clinical relevance. An in vitro cell model was employed to investigate the roles of noncanonical inflammasomes in macrophages in response to HAdV infection.

Results

Bioinformatics analysis showed that inflammasome-related genes, including caspase-4 and caspase-5, were enriched in adenovirus pneumonia. Moreover, caspase-4 and caspase-5 expression levels were significantly increased in the cells isolated from peripheral blood and broncho-alveolar lavage fluid (BALF) of pediatric patients with adenovirus pneumonia, and positively correlated with clinical parameters of inflammatory damage. In vitro experiments revealed that HAdV infection promoted caspase-4/5 expression, activation and pyroptosis in differentiated THP-1 (dTHP-1) human macrophages via NF-κB, rather than STING signaling pathway. Interestingly, silencing of caspase-4 and caspase-5 in dTHP-1 cells suppressed HAdV-induced noncanonical inflammasome activation and macrophage pyroptosis, and dramatically decreased the HAdV titer in cell supernatants, by influencing virus release rather than other stages of virus life cycle.

Discussion

In conclusion, our study demonstrated that HAdV infection induced macrophage pyroptosis by triggering noncanonical inflammasome activation via a NF-kB-dependent manner, which may explore new perspectives on the pathogenesis of HAdV-induced inflammatory damage. And high expression levels of caspase-4 and caspase-5 may be a biomarker for predicting the severity of adenovirus pneumonia.

Lactate dehydrogenase and the severity of adenoviral pneumonia in children: A meta-analysis

Background

Children with severe adenoviral pneumonia (ADVP) have poor prognosis and high risk of mortality. We performed a meta-analysis to evaluate the association between pretreatment lactate dehydrogenase (LDH) and severity, postinfectious bronchiolitis obliterans (PIBO), and mortality in children with ADVP.

Methods

Relevant observational studies were identified by search of PubMed, Embase, Web of Science, Wanfang, and CNKI databases from inception to August 3, 2022. A random effect model was used to pool the results by incorporating the potential between-study heterogeneity.

Results

Overall, 23 studies with 4,481 children with ADVP were included in this meta-analysis. Results of meta-analysis showed that children with severe ADVP had a significantly higher level of pretreatment LDH as compared to those with non-severe ADVP (standard mean difference [SMD]: 0.51, 95% confidence interval [CI]: 0.36 to 0.66, p < 0.001; I 2 = 69%). Besides, pooled results also suggested that the pretreatment LDH was significantly higher in children who developed PIBO as compared to those who did not (SMD: 0.47, 95% CI: 0.09 to 0.84, p = 0.02, I 2 = 80%). Finally, results of the meta-analysis also confirmed that a higher pretreatment LDH (>500 IU/L) was a risk factor of increased mortality during hospitalization (odds ratio: 3.10, 95% CI: 1.62 to 5.92, p < 0.001, I 2 = 0%). Sensitivity analyses by excluding one dataset at a time showed consistent results.

Conclusion

High pretreatment LDH may be associated with disease severity, development of PIBO, and increased risk of mortality in children with ADVP.

Molecular epidemiology of human adenoviruses in children with and without respiratory symptoms: Preliminary findings from a case-control study

Background

Human adenovirus (HAdV) is an important viral agent in children which can lead to severe acute respiratory infection (SARI). Reports on molecular epidemiology of HAdVs in Iran are limited. This case-control study is conducted to compare the HAdV infection rate and molecular epidemiology among two groups of children with and without respiratory symptoms in Tehran, Iran during 2018–2019.

Methods

Nested PCR was performed on 120 oropharyngeal swabs taken from children aged five and younger with SARI who were hospitalized as the case group, and 120 oropharyngeal swabs were collected from children of the same age without respiratory symptoms as the control group. For positive samples Sanger sequencing was done and a phylogenetic tree was drawn afterward.

Results

Out of 120 cases, 8 (6.6%) tested positive for eachHAdV types including 6 (75%) HAdV-B7, 1 (12.5%) HAdV-C2, and 1 (12.5%) HAdV-C6. Among the control group, out of 120 samples, 8 (6.6%) were positive comprising 5 (62.5%) HAdV-C5, 2 (25%) HAdV-F41, and 1 (12.5%) HAdV-C6.

Conclusion

The present study indicated a different viewpoint of HAdV molecular epidemiology in which the genotypes were compared in children with and without respiratory symptoms. HAdV prevalence was equally common in cases and controls but different genotypes were detected in these two groups. HAdV-B7 was the main type among children with SARI, dissimilar to children with no respiratory symptoms where HAdV-C5 was the predominant type. Detecting HAdV-F in oropharyngeal swabs was a rare finding, which requires further investigation.

Clinical and imaging findings of patients diagnosed with adenovirus-positive pneumonia during 2015-2019 in Shanghai, China

BACKGROUND

This study was to describe the clinical characteristics, chest CT image findings, and potential role of T cells immunity in adenovirus positive pneumonia.

METHODS

In this retrospective study, medical records of 53 adult Adv+ patients who were admitted to the Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, from May 2015 to August 2019 were included. The presence of adenovirus and other respiratory viruses was detected using polymerase chain reaction of throat swabs samples. Clinical features and chest computed tomography (CT) findings were compared between patients with Adv+ pneumonia and Adv+ non-pneumonia.

RESULTS

The top 3 most commonly occurring symptoms in Adv+ pneumonia patients were fever (66.7%), cough (63.3%), and tachypnea (16.7%). Patients with Adv+ pneumonia showed significantly higher rates of cough and fever and longer duration of hospitalization than patients with Adv+ non-pneumonia. In the Adv+ pneumonia group, consolidation (73.3%) was the most common imaging finding on chest CT scan, and the likelihood of involvement of bilateral lobes (60%) was high. Classical conspicuous consolidation with surrounding ground-glass opacity was observed in 5 (16.6%) patients with Adv+ pneumonia. Patients with Adv+ pneumonia showed a higher inhibition of T-cell immunity than did patients with Adv+ non-pneumonia, and counts of CD3+, CD4+, and CD8+ T-cells may predict the presence of pneumonia in Adv+ patients.

DISCUSSION

With regard to Adv+ pneumonia, the most frequent symptoms were cough and fever, and the most common CT pattern was consolidation; classical CT findings such as consolidation with surrounding ground-glass opacity could also be observed. Furthermore, our data indicated the incidence of abrogated cellular immunity in patients with Adv+ pneumonia.

The Clinical Risk Factors of Adenovirus Pneumonia in Children Based on the Logistic Regression Model: Correlation with Lactate Dehydrogenase

Methods

Children with bacterial pneumonia (41 cases) and adenovirus pneumonia (179 cases) hospitalized in Tianjin Children's Hospital from January to October 2020 were selected. The differences in baseline and clinical characteristics between children with two pneumonias, respectively, were compared via the chi-square test and Wilcox test. The Least Absolute Shrinkage and Selection Operator (LASSO) model was applied to screen the pneumonia type-related characteristics. Patients were randomly divided into the training set (n = 154) and test set (n = 66). The logistic model was constructed using the screened characteristics in the training set to predict whether the cases are bacterial pneumonia or adenovirus pneumonia. Finally, the model was validated by receiver operating characteristic (ROC) curve and area under curve (AUC) in the test set.

Results

The age (p < 0.001), hospital stay (p < 0.001), tonsil condition (p < 0.001), interleukin-6 (IL-6; p=0.033), and lactate dehydrogenase (LDH; p < 0.001) between children with bacterial pneumonia and adenovirus pneumonia were significantly different. Sex, tonsil condition, age, hospital stay, r-glutamyltransferase (r-GT), and LDH levels were the factors associated with the types of pneumonia. Compared with bacterial pneumonia, children with adenovirus pneumonia were younger (OR = 0.207, 95% CI: 0.041-0.475), with longer hospital stay (OR = 7.974, 95% CI: 2.626-74.354) and higher LDH expression level (OR = 1.025, 95% CI: 1.006-1.060). 92.4% types of pneumonia were correctly predicted, and the AUC value of the model was 0.981.

Conclusion

The LDH level was the associated factor to predict the types of pneumonia. Adenovirus pneumonia was associated with earlier age and longer hospital stay than bacterial pneumonia. The established model can well predict the types of pneumonia in children and provide clinical basis for guiding the individualized treatment of children.

Clinical features and epidemiological analysis of respiratory human adenovirus infection in hospitalized children: a cross-sectional study in Zhejiang

Background

HAdV is one of the common pathogens in hospitalized children with acute respiratory infections (ARIs). We aim to describe the clinical and laboratory features, epidemiological characteristics, and HAdV species and/or types of inpatients with HAdV respiratory infections.

Methods

Respiratory samples were gathered from inpatients diagnosed ARIs in Children’s Hospital, Zhejiang University School of Medicine, and were detected by using Direct Immunofluorescence Assay from 2018 to 2019. PCR amplification and sequencing of the hypervariable zone of hexon gene were used for genotyping. The clinical and laboratory features, and HAdV genotyping, and epidemiological characteristic analysis were retrospectively performed.

Results

Of 7072 samples collected, 488 were identified as HAdV-positive. The overall detection rate was 6.9%. The peaked detection rate was 14.1% in January 2019. HAdV-positive cases with ARIs mainly appeared in winter. The detection rate was highest among children between 6 months and 2 years (8.7%, 123/1408). Clinical diagnosis included pneumonia (70.3%, 343/488), bronchitis (7.0%, 34/488) and acute upper respiratory tract infection (22.7%, 111/488). The common clinical manifestations were fever (93.4%, 456/488), cough (94.7%, 462/488), wheezing (26.2%, 128/488), and shortness of breath (14.8%, 72/488). 213 (43.6%) cases had co-infection and 138 (28.3%) cases had extrapulmonary symptoms. 96(19.7%) cases had intrapulmonary and intrathoracic complications.78 (16.0%) had an underlying condition, most of which were congenital heart diseases (20.5%, 16/78). The proportions of hyperpyrexia, duration of fever > 10 days, severe pneumonia, and wheezing in the co-infection group were remarkably higher than those in HAdV single-infection group (all p < 0.05). The proportions of duration of hospitalization, duration of fever > 10 days, wheezing, shortness of breath, change in level of consciousness, serosal fluids, extrapulmonary symptoms, co-infections and underlying diseases were significantly higher in severe pneumonia group than those in the mild pneumonia group (all p < 0.05). Four HAdV species were successfully identified in 155 cases and presented by 8 genotypes. HAdV-B3 (56.1%, 87/155) and HAdV -B7 (31.0%, 48/155) were the most predominant detected types and occurred commonly in different severity groups (p = 0.000), while, HAdV-B55 was detected only in the severe group. HAdV-B7’s detection rate in the severe pneumonia group was significantly higher than the non-severe pneumonia group.

Conclusion

HAdV detection rate is related to age and season. Bronchopneumonia accounts for about 70% HAdV-positive inpatients. The common clinical manifestations include hyperpyrexia, cough, wheezing, and shortness of breath. HAdV-B3 and HAdV-B7 are the most common types in children diagnosed with respiration infections.

Clinical Characteristics and Outcomes of Severe Pneumonia in Children Under 5 Years Old With and Without Adenovirus Infection in Guangzhou

Objectives: To identify the differences of clinical characteristics and outcomes of severe pneumonia in children under 5 years old with and without adenovirus infection. Methods: A retrospective cohort study was conducted in three pediatric hospitals in Guangzhou, China. In total, 1,595 children under the age of 5 with WHO-defined severe pneumonia had adenovirus testing performed between January 1, 2009 and December 31, 2019. Demographics, complications, the first routine laboratory findings, therapeutic records, and clinical outcome were collected from electronic medical records. We compared characteristics of children with and without adenovirus infection. Results: Adenovirus was detected in 75 (4.7%) out of 1,595 children with severe pneumonia. Cases with adenovirus infection were more likely to be boys (74.7 vs. 63.0%), older than 1 year old (78.7 vs. 25.1%), but less likely to have mixed virus infections (25.3 vs. 92.9%) and combined with cardiovascular disease (12.0 vs. 39.7%), and had more abnormal laboratory results than cases without adenovirus infection. Antiviral therapy (4.9%) was rarely used in children with severe pneumonia, but antibiotic therapy (65.3%) was commonly used, especially in cases with adenovirus infection (91.9%). Children infected with adenovirus (9.3 vs. 2.5%) were also hospitalized longer and had a higher mortality within 30 days of hospitalization. Conclusions: Children with severe pneumonia under 5 years old with adenovirus infection had more abnormal laboratory findings and more severe clinical outcomes than cases without adenovirus infection. More attention should be focused on the harm caused by adenovirus infection.

A bivalent live-attenuated vaccine candidate elicits protective immunity against human adenovirus types 4 and 7

Human adenovirus types 4 (HAdV4) and 7 (HAdV7) often lead to severe respiratory diseases and occur epidemically in children, adults, immune deficiency patients, and other groups, leading to mild or severe symptoms and even death. However, no licensed adenovirus vaccine has been approved in the market for general use. E3 genes of adenovirus are generally considered nonessential for virulence and replication; however, a few studies have demonstrated that the products of these genes are also functional. In this study, most of the E3 genes were deleted, and two E3-deleted recombinant adenoviruses (ΔE3-rAdVs) were constructed as components of the vaccine. After E3 deletion, the replication efficiencies and cytopathogenicity of ΔE3-rAdVs were reduced, indicating that ΔE3-rAdVs were attenuated after E3 genes deletion. Furthermore, single immunization with live-attenuated bivalent vaccine candidate protects mice against challenge with wild-type human adenovirus types 4 and 7, respectively. Vaccinated mice demonstrated remarkably decreased viral loads in the lungs and less lung pathology compared to the control animals. Taken together, our study confirms the possibility of the two live-attenuated viruses as a vaccine for clinic use and illustrates a novel strategy for the construction of an adenovirus vaccine.

Human Adenovirus Type 7 Infections in Hubei, China During 2018-2019: Epidemic Features and Genetic Characterization of the Detected Viruses

Human adenoviruses (HAdVs) type 7 can cause severe respiratory disease. During the period between December 2018 and August 2019, HAdV-7 infection was identified in 129 patients in Wuhan Children's Hospital, Hubei Province, China. Samples were collected from hospitalized children and metagenomic sequencing was applied to detect the HAdV infections. Hemophagocytic lymphohistiocystosis (HLH) related to HAdV infections was observed in some patients clinically and patients were divided into two groups based on this to test the differences among clinical indicators. Genome variation, in silico restriction endonuclease analysis (REA), and phylogenetic analyses were carried out to show the genome characterization of HAdV-7 in this study. It was found that many indicators, such as all blood routine indicators, in patients of the HLH group showed significant levels. In this study, REA revealed that HAdV-7 might belong to genome 7d and genome variation analysis displayed the stable genome of HAdV. HAdV-7 is an ongoing threat to the public, and global surveillance should be established.

Taxonomy of Pathogen Codetection in Pediatric Case Fatalities with Adenoviral Respiratory Infection

Objective The aim of this study was to determine the prevalence and taxonomy of pathogen codetection in pediatric case fatalities associated with adenoviral respiratory infection.

Methods This retrospective case series included 107 pediatric case fatalities associated with adenoviral respiratory infection.

Results We observed a high rate of pathogen codetection with broad diversity from both respiratory and nonrespiratory sources. We noted differences in codetection characteristics based on immune status; most notably that immunocompromised cases were more likely to have bacteremia and adenoviremia.

Conclusions In pediatric case fatalities associated with adenoviral respiratory infection, we observed a high degree of pathogen codetection.

MAGI-1 PDZ2 Domain Blockade Averts Adenovirus Infection via Enhanced Proteolysis of the Apical Coxsackievirus and Adenovirus Receptor

Adenoviruses (AdVs) are etiological agents of gastrointestinal, heart, eye, and respiratory tract infections that can be lethal for immunosuppressed people. Many AdVs use the coxsackievirus and adenovirus receptor (CAR) as a primary receptor. The CAR isoform resulting from alternative splicing that includes the eighth exon, CAREx8, localizes to the apical surface of polarized epithelial cells and is responsible for the initiation of AdV infection. We have shown that the membrane level of CAREx8 is tightly regulated by two MAGI-1 PDZ domains, PDZ2 and PDZ4, resulting in increased or decreased AdV transduction, respectively. We hypothesized that targeting the interactions between the MAGI-1 PDZ2 domain and CAREx8 would decrease the apical CAREx8 expression level and prevent AdV infection. Decoy peptides that target MAGI-1 PDZ2 were synthesized (TAT-E6 and TAT-NET1). PDZ2 binding peptides decreased CAREx8 expression and reduced AdV transduction. CAREx8 degradation was triggered by the activation of the regulated intramembrane proteolysis (RIP) pathway through a disintegrin and metalloproteinase (ADAM17) and γ-secretase. Further analysis revealed that ADAM17 interacts directly with the MAGI-1 PDZ3 domain, and blocking the PDZ2 domain enhanced the accessibility of ADAM17 to the substrate (CAREx8). Finally, we validated the efficacy of TAT-PDZ2 peptides in protecting the epithelia from AdV transduction in vivo using a novel transgenic animal model. Our data suggest that TAT-PDZ2 binding peptides are novel anti-AdV molecules that act by enhanced RIP of CAREx8 and decreased AdV entry. This strategy has additional translational potential for targeting other viral receptors that have PDZ binding domains, such as the angiotensin-converting enzyme 2 receptor. IMPORTANCE Adenovirus is a common threat in immunosuppressed populations and military recruits. There are no currently approved treatments/prophylactic agents that protect from most AdV infections. Here, we developed peptide-based small molecules that can suppress AdV infection of polarized epithelia by targeting the AdV receptor, coxsackievirus and adenovirus receptor (CAREx8). The newly discovered peptides target a specific PDZ domain of the CAREx8-interacting protein MAGI-1 and decrease AdV transduction in multiple polarized epithelial models. Peptide-induced CAREx8 degradation is triggered by extracellular domain (ECD) shedding through ADAM17 followed by γ-secretase-mediated nuclear translocation of the C-terminal domain. The enhanced shedding of the CAREx8 ECD further protected the epithelium from AdV infection. Taken together, these novel molecules protect the epithelium from AdV infection. This approach may be applicable to the development of novel antiviral molecules against other viruses that use a receptor with a PDZ binding domain.

Application of Human Adenovirus Genotyping by Phylogenetic Analysis in an Outbreak to Identify Nosocomial Infection

Nosocomial infections are common in pediatric patients and can be fatal in infants and immunocompromised patients. In September 2018, a high positive rate of human adenovirus HAdV was occurred among hospitalized children in the Children's Hospital Affiliated to the Capital Institute of Paediatrics in Beijing. To investigate whether this outbreak of HAdV was related to nosocomial infections or the result of community infections, we collected respiratory specimens from patients with acute respiratory infections in a respiratory ward during June to December 2018, and screened for respiratory viruses. Among 1,840 cases included, 95 (5.2%, 95/1840) were positive for HAdV and 81 were genotyped based on phylogenetic analysis, including seven as HAdV-1 (8.6%), 30 HAdV-3 (37.0%), two HAdV-6 (2.5%), and 42 HAdV-7 (51.9%). More HAdV-positive samples were collected in August (4.7%, 12/255), September (15.0%, 41/274) and October (6.9%, 17/247), with a peak in September 2018. By combining the results of HAdV phylogenetic analysis with clinical data of patients, there were 77 cases (4.2%, 77/1840; 81.1%, 77/95) excluded from nosocomial infections, eight cases representing possible infections transmitted by visitors or attending parents, three cases without sequences that might have been due to infection transmitted by roommates positive for HAdV, one case of a roommate without an HAdV sequence, and six cases that shared highly homologous sequences with those of their roommates, for which nosocomial infections might be considered. In conclusion, genotyping of HAdVs based on phylogenetic analysis combined with clinical information provides a powerful method to distinguish nosocomial infections from community acquired infection, especially when tracing the origins of nosocomial infections.

Patient hematology during hospitalization for viral pneumonia caused by SARS-CoV-2 and non-SARS-CoV-2 agents: a retrospective study

Background

Hematological comparison of coronavirus disease (COVID-19) and other viral pneumonias can provide insights into COVID-19 treatment.

Methods

In this retrospective case–control single-center study, we compared the data of 126 patients with viral pneumonia during different outbreaks [severe acute respiratory syndrome (SARS) in 2003, influenza A (H1N1) in 2009, human adenovirus type 7 in 2018, and COVID-19 in 2020].

Results

One of the COVID-19 characteristics was a continuous decline in the hemoglobin level. The neutrophil count was related to the aggravation of COVID-19 and SARS. Thrombocytopenia occurred in patients with SARS and severe COVID-19 even at the recovery stage. Lymphocytes were related to the entire course of adenovirus infection, recovery of COVID-19, and disease development of SARS.

Conclusions

Dynamic changes in hematological counts could provide a reference for the pathogenesis and prognosis of pneumonia caused by respiratory viruses in clinics.

Nonreplicating Adenoviral Vectors: Improving Tropism and Delivery of Cancer Gene Therapy

Recent preclinical and clinical studies have used viral vectors in gene therapy research, especially nonreplicating adenovirus encoding strategic therapeutic genes for cancer treatment. Adenoviruses were the first DNA viruses to go into therapeutic development, mainly due to well-known biological features: stability in vivo, ease of manufacture, and efficient gene delivery to dividing and nondividing cells. However, there are some limitations for gene therapy using adenoviral vectors, such as nonspecific transduction of normal cells and liver sequestration and neutralization by antibodies, especially when administered systemically. On the other hand, adenoviral vectors are amenable to strategies for the modification of their biological structures, including genetic manipulation of viral proteins, pseudotyping, and conjugation with polymers or biological membranes. Such modifications provide greater specificity to the target cell and better safety in systemic administration; thus, a reduction of antiviral host responses would favor the use of adenoviral vectors in cancer immunotherapy. In this review, we describe the structural and molecular features of nonreplicating adenoviral vectors, the current limitations to their use, and strategies to modify adenoviral tropism, highlighting the approaches that may allow for the systemic administration of gene therapy.

Clinical Characteristics of 204 Children With Human Adenovirus Type 7 Pneumonia Identified by Whole Genome Sequencing in Liuzhou, China

BACKGROUND

Clinical knowledge of human adenovirus type 7 (HAdV-7) pneumonia in children remains limited. Moreover, predictors for disease severity are largely unknown.

METHODS

This is a retrospective study of children hospitalized at Liuzhou Maternal and Child Health Hospital, China, with HAdV-7 pneumonia in 2018-2019. Demographics, clinical characteristics, laboratory results, and imaging data were collected. HAdV-7 was identified in plasma using whole genome sequencing, which yielded quantitative HAdV-7 sequence numbers.

RESULTS

There were 204 children; 145 (71%) were <2 years of age. There were 68 children with severe pneumonia (SP) and 136 with nonsevere pneumonia (NSP). Up to 43% in SP group with respiratory failure (SP-RF) were <12 months of age. Median duration of fever before hospitalization was shorter in NSP group than SP groups (P < 0.01). Fourteen (6.9%) underwent mechanical ventilation. There was a significant difference in mean plasma HAdV-7 sequence numbers among SP-RF, SP without respiratory failure (SP-NRF), and NSP groups (2485 ± 165, 2034 ± 124, and 286 ± 35, respectively) (P < 0.01). In a logistic regression analysis, we found that elevated plasma HAdV-7 sequence numbers significantly increased the risk of severe HAdV-7 pneumonia (OR 1.80, 95% confidence interval: 1.59-2.60, P < 0.01) after adjusting for age, fever duration, platelet counts, and serum lactate dehydrogenase levels.

CONCLUSIONS

Over two-thirds of children hospitalized with HAdV-7 pneumonia were <2 years of age. Approximately 40% of those with SP associated with respiratory failure were <12 months of age. Those with SP exhibited higher plasma HAdV-7 sequence numbers. Thus, plasma HAdV-7 sequence numbers have a potential in predicting severity of HAdV-7 pneumonia in children.

Risk Factors for the Development of Hemophagocytic Lymphohistiocytosis in Children With Severe Adenovirus Pneumonia: A Single-Center Retrospective Study

Objective: To investigate and analyze the relevant risk factors for hemophagocytic lymphohistiocytosis (HLH) in children with severe adenovirus pneumonia (SAP). Methods: A retrospective study of children with SAP was performed in 30 cases developing HLH and 94 cases not developing HLH from December 2018 to August 2019. The binary logistic regression analysis was used to identify risk factors that were significantly associated with the development of HLH after the univariate analysis, and the receiver operating characteristic (ROC) curve was performed to find out the cut-off value for the significant relevant factors. Results: Two factors were associated with the development of HLH, which were the length of fever (OR = 1.331, 95%CI: 1.002-1.769) and triglycerides (TG) (OR = 17.345, 95%CI: 1.358-221.538). The cut-off value of the length of fever was 12.5 days, and the cut-off value of TG was 3.02 mmol/L. Conclusion: Children with SAP who had a duration of fever over 12.5 days and the TG level over 3.02 mmol/L are more likely to develop HLH.

Outbreak of severe acute respiratory infection in Southern Province, Sri Lanka in 2018: a cross-sectional study

OBJECTIVES

To determine aetiology of illness among children and adults presenting during outbreak of severe respiratory illness in Southern Province, Sri Lanka, in 2018.

DESIGN

Prospective, cross-sectional study.

SETTING

1600-bed, public, tertiary care hospital in Southern Province, Sri Lanka.

PARTICIPANTS

410 consecutive patients, including 371 children and 39 adults, who were admitted with suspected viral pneumonia (passive surveillance) or who met case definition for acute respiratory illness (active surveillance) in May to June 2018.

RESULTS

We found that cocirculation of influenza A (22.6% of cases), respiratory syncytial virus (27.8%) and adenovirus (AdV) (30.7%; type B3) was responsible for the outbreak. Mortality was noted in 4.5% of paediatric cases identified during active surveillance. Virus type and viral coinfection were not significantly associated with mortality.

CONCLUSIONS

This is the first report of intense cocirculation of multiple respiratory viruses as a cause of an outbreak of severe acute respiratory illness in Sri Lanka, and the first time that AdV has been documented as a cause of a respiratory outbreak in the country. Our results emphasise the need for continued vigilance in surveying for known and emerging respiratory viruses in the tropics.

Bioinformatics analysis reveals four major hexon variants of human adenovirus type-3 (HAdV-3) as the potential strains for development of vaccine and siRNA-based therapeutics against HAdV-3 respiratory infections

Human adenovirus type 3 (HAdV-3) encompasses 15-87% of all adenoviral respiratory infections. The significant morbidity and mortality, especially among the neonates and immunosuppressed patients, demand the need for a vaccine or a targeted antiviral against this type. However, due to the existence of multiple hexon variants (3Hv-1 to 3Hv-25), the selection of vaccine strains of HAdV-3 is challenging. This study was designed to evaluate HAdV-3 hexon variants for the selection of potential vaccine candidates and the use of hexon gene as a target for designing siRNA that can be used as a therapy. Based on the data of worldwide distribution, duration of circulation, co-circulation and their percentage among all the variants, 3Hv-1 to 3Hv-4 were categorized as the major hexon variants. Phylogenetic analysis and the percentage of homology in the hypervariable regions followed by multi-sequence alignment, zPicture analysis and restriction enzyme analysis were carried out. In the phylogram, the variants were arranged in different clusters. The HVR encoding regions of hexon of 3Hv-1 to 3Hv-4 showed 16 point mutations resulting in 12 amino acids substitutions. The homology in HVRs was 81.81-100%. Therefore, the major hexon variants are substantially different from each other which justifies their inclusion as the potential vaccine candidates. Interestingly, despite the significant differences in the DNA sequence, there were many conserved areas in the HVRs, and we have designed functional siRNAs form those locations. We have also designed immunogenic vaccine peptide epitopes from the hexon protein using bioinformatics prediction tool. We hope that our developed siRNAs and immunogenic vaccine peptide epitopes could be used in the future development of siRNA-based therapy and designing a vaccine against HAdV-3.

Efficacy of fiberoptic bronchoscopy and bronchoalveolar lavage in childhood-onset, complicated plastic bronchitis

BACKGROUND

Plastic bronchitis (PB) is a rare, variable, and potentially fatal disease. This study aimed to assess the efficacy of fiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) in treating children with PB.

METHODS

In total, 15 children with PB, between 2012 and 2020, were enrolled in our study. Within 12 hours of admission, FOB and BAL were performed and reviewed under local anesthesia and sedation. Before and after FOB, clinical findings and chest imaging were evaluated.

RESULTS

Regarding the onset of symptoms before FOB, all cases had prominent cough for 7.00 ± 4.55 days, and 14 had persistent high fever. In total, 13 cases had complete obstruction from bronchial casts, consistent with consolidated lesions; 2 had partial airway obstruction. Within 3 days, complete resolution was revealed in nine cases. Overall, six cases underwent repeated FOB (range, 2-3 times) for persistent atelectasis and airway obstruction. Except for two cases with type 2 PB, cast histology confirmed type 1 PB for all cases. Only eight children had minor intra- and post-procedure complications. Reverse transcription-polymerase chain reaction for Mycoplasma pneumoniae in sputum and BAL samples were positive in 13 cases. Next-generation sequencing of the BAL samples was positive for adenovirus and Human parainfluenza virus in one case, respectively. During 1 month to 7 years of follow-up, no patient developed PB recurrence, asthmatic attacks, or chronic cough.

CONCLUSIONS

Early FOB and BAL were effective in alleviating clinical findings, atelectasis, and airway obstruction. Serial FOB could be performed in patients with recurrent symptoms.

Adenoviral Respiratory Infection-Associated Mortality in Children: A Retrospective Case Series

Viral respiratory infections are a leading cause of illness and hospitalization in young children worldwide. Case fatality rates in pediatric patients with adenoviral lower respiratory tract infection requiring intensive care unit (ICU) admission have been reported between 7 and 22%. We investigated the demographics and clinical characteristics in pediatric mortalities associated with adenoviral respiratory infection at 12 academic children's hospitals in the United States. There were 107 mortality cases included in our study, 73% of which had a chronic medical condition. The most common chronic medical condition was immunocompromised state in 37 cases (35%). The incidences of pediatric acute respiratory distress syndrome (78%) and multiple organ dysfunction syndrome (94%) were profound. Immunocompetent cases were more likely to receive mechanical ventilation within the first hour of ICU admission (60 vs. 14%, p < 0.001) and extracorporeal membrane oxygenation (27 vs. 5%, p = 0.009), and less likely to receive continuous renal replacement therapy (20 vs. 49%, p = 0.002) or have renal dysfunction (54 vs. 78%, p = 0.014) as compared with immunocompromised cases. Immunocompromised cases were more likely to have bacteremia (57 vs. 16%, p < 0.001) and adenoviremia (51 vs. 17%, p < 0.001) and be treated with antiviral medications (81 vs. 26%, p < 0.001). We observed a high burden of nonrespiratory organ system dysfunction in a cohort of pediatric case fatalities with adenoviral respiratory infection. The majority of cases had a chronic medical condition associated with an increased risk of complications from viral respiratory illness, most notably immunocompromised state. Important treatment differences were noted between immunocompromised and immunocompetent cases.

Molecular Epidemiology and Clinical Features Analysis of Respiratory Adenovirus Infections Reveals Correlations between Genotype, Inflammatory Biomarkers, and Disease Severity

Background

Human adenoviruses (HAdVs) are commonly causing respiratory disease. We molecularly genotyped HAdV circulating in Chinese hospitalized children with respiratory infections and summarized the clinical profiles and common inflammatory biomarkers, so as to better determine their associations with disease severity.

Method

Children with respiratory single HAdV infection cases that occurred from December 2017 to March 2019 were enrolled for a cross-sectional study. Clinical/laboratory features based on the genotypes of respiratory HAdV infection were reviewed for comparative analysis.

Results

A total of 84 patients were enrolled, and HAdV types were identified from 82 patients. Species B (HAdV-7, 44%; HAdV-3, 43%, and HAdV-14, 5%) was the most common, followed by C (HAdV-2, 4% and HAdV-1, 1%) and E (HAdV-4, 1%). Severe HAdV infection and HAdV-7 infection groups were associated with significantly longer duration of fever and hospitalized days, higher morbidity of tachypnea/dyspnea, more pleural effusion, more respiratory rales, more frequently required mechanical ventilation, and significantly higher fatality rate. The elevated procalcitonin (PCT) and C-reactive protein (CRP) levels were significantly associated with severe HAdV infection.

Conclusions

HAdV-7 and HAdV-3 were the most common types among children with respiratory adenovirus infection; vaccines against these two genotypes are in urgent need. PCT and CRP are significantly associated with the severity of HAdV infection.

Binding Mechanism Elucidation of the Acute Respiratory Disease Causing Agent Adenovirus of Serotype 7 to Desmoglein-2

The study of viruses causing acute respiratory distress syndromes (ARDS) is more essential than ever at a time when a virus can create a global pandemic in a matter of weeks. Among human adenoviruses, adenovirus of serotype 7 (HAdV7) is one of the most virulent serotypes. This virus regularly re-emerges in Asia and has just been the cause of several deaths in the United States. A critical step of the virus life cycle is the attachment of the knob domain of the fiber (HAd7K) to the cellular receptor desmoglein-2 (DSG2). Complexes between the fiber knob and two extracellular domains of DSG2 have been produced. Their characterization by biochemical and biophysical methods show that these two domains are sufficient for the interaction and that the trimeric HAd7K could accommodate up to three DSG2 receptor molecules. The cryo-electron microscopy (cryo-EM) structure of these complexes at 3.1 Å resolution confirmed the biochemical data, and allowed the identification of the critical amino acid residues for this interaction, which shows similarities with other DSG2 interacting adenoviruses, despite a low homology in the primary sequences.

Adenovirus 7 Induces Interlukin-6 Expression in Human Airway Epithelial Cells via p38/NF-κB Signaling Pathway

Human Adenovirus (AdV) infection is very common and usually has a significant impact on children. AdV-induced inflammation is believed to be one of the main causes of severe symptoms. However, an inflammatory response profile in the airway in AdV-infected children is still lacking, and the mechanism underlying AdV-induced inflammation in the airway is also poorly understood. In the current study, we determined the expression of a panel of inflammation cytokines in the airway samples from AdV 7 infected children and further investigated the molecular mechanism underlying AdV 7-induced cytokine expression. Our results showed that eight out of 13 tested inflammatory cytokines were significantly increased in nasal washes of AdV 7-infected children comparing to healthy control, with IL-6 showing the highest enhancement. AdV 7 infection of bronchial epithelial cell line and primary airway epithelial cells confirmed that AdV 7 increased IL-6 mRNA and protein expression in an infection dose-dependent manner. Promoter analysis revealed that AdV 7 infection transactivated IL-6 promoter and a NF-κB binding site in IL-6 promoter was involved in the transactivation. Further analysis showed that upon AdV 7 infection, NF-κB p65 was phosphorylated and translocated into nucleus and bound onto IL-6 promoter. Signaling pathway analysis revealed that p38/NF-κB pathway was involved in AdV 7 infection induced IL-6 elevation. Taken together, our study shows that AdV 7 infection triggers the expression of a range of inflammatory cytokines including IL-6 in the airway of infected children, and AdV 7 enhances IL-6 expression by transactivating IL-6 promoter via p38/NF-κB signaling pathway. Findings of our current study have provided more information toward a better understanding of AdV-induced airway inflammation, which might also benefit the development of intervention strategies.

Inhibition of Human Adenovirus Replication by the Importin α/β1 Nuclear Import Inhibitor Ivermectin

Human adenoviruses (HAdV) are ubiquitous within the human population and comprise a significant burden of respiratory illnesses worldwide. Pediatric and immunocompromised individuals are at particular risk for developing severe disease; however, no approved antiviral therapies specific to HAdV exist. Ivermectin is an FDA-approved broad-spectrum antiparasitic drug that also exhibits antiviral properties against a diverse range of viruses. Its proposed function is inhibiting the classical protein nuclear import pathway mediated by importin-α (Imp-α) and -β1 (Imp-β1). Many viruses, including HAdV, rely on this host pathway for transport of viral proteins across the nuclear envelope. In this study, we show that ivermectin inhibits HAdV-C5 early gene transcription, early and late protein expression, genome replication, and production of infectious viral progeny. Similarly, ivermectin inhibits genome replication of HAdV-B3, a clinically important pathogen responsible for numerous recent outbreaks. Mechanistically, we show that ivermectin disrupts binding of the viral E1A protein to Imp-α without affecting the interaction between Imp-α and Imp-β1. Our results further extend ivermectin's broad antiviral activity and provide a mechanistic underpinning for its mode of action as an inhibitor of cellular Imp-α/β1-mediated nuclear import.IMPORTANCE Human adenoviruses (HAdVs) represent a ubiquitous and clinically important pathogen without an effective antiviral treatment. HAdV infections typically cause mild symptoms; however, individuals such as children, those with underlying conditions, and those with compromised immune systems can develop severe disseminated disease. Our results demonstrate that ivermectin, an FDA-approved antiparasitic agent, is effective at inhibiting replication of several HAdV types in vitro This is in agreement with the growing body of literature suggesting ivermectin has broad antiviral activity. This study expands our mechanistic knowledge of ivermectin by showing that ivermectin targets the ability of importin-α (Imp-α) to recognize nuclear localization sequences, without effecting the Imp-α/β1 interaction. These data also exemplify the applicability of targeting host factors upon which viruses rely as a viable antiviral strategy.

The coxsackievirus and adenovirus receptor: virological and biological beauty

The coxsackievirus and adenovirus receptor (CAR) is an essential multifunctional cellular protein that is only beginning to be understood. CAR serves as a receptor for many adenoviruses, human group B coxsackieviruses, swine vesicular disease virus, and possibly other viruses. While named for its function as a viral receptor, CAR is also involved in cell adhesion, immune cell activation, synaptic transmission, and signaling. Knockout mouse models were first to identify some of these biological functions; however, tissue-specific model systems have shed light on the complexity of different CAR isoforms and their specific activities. Many of these functions are mediated by the large number of interacting proteins described so far, and several new putative interactions have recently been discovered. As antiviral and gene therapy strategies that target CAR continue to emerge, future work poised to understand the biological implications of manipulating CAR in vivo is critical.

[Clinical features of severe type 7 adenovirus pneumonia: an analysis of 45 cases]

OBJECTIVE

To study the clinical features of severe type 7 adenovirus pneumonia in children.

METHODS

A retrospective analysis was performed for the clinical data of children who were diagnosed with severe type 7 adenovirus pneumonia from February to June, 2019.

RESULTS

Among the 45 children, the male/female ratio was 3:2 and the median age was 14 months. All children had repeated fever, cough, and pulmonary moist rales, and the mean duration of fever was 14±4 days. The median time from fever to dyspnea was 8 days, and the time from fever to mechanical ventilation was 11.6±2.5 d. There was no significant increase in white blood cell count, with neutrophils as the main type. There were slight reductions in hemoglobin and albumin, while platelet and fibrinogen remained normal. There were increases in aspartate aminotransferase, lactate dehydrogenase, procalcitonin, and C-reaction protein. The detection rate of mixed pathogens was 84%. Effusion in both lungs was the major change on chest imaging (64%). Bronchoscopic manifestations were endobronchitis, tracheomalacia, and plastic bronchitis. The incidence rate of respiratory complications was 100%, and extrapulmonary complications mainly involved the circulatory system (47%), digestive system (36%), and nervous system (31%). Among the 45 children, 16 were administered with 400 mg/kg intravenous immunoglobulin (IVIG) daily for 5 days, with a mean duration of fever of 16±5 days, and 29 were administered with 1 g/kg IVIG daily for 2 days, with a mean duration of fever of 13±4 days; there was a significant difference in the mean duration of fever between the two groups (P=0.046). The overall mortality rate was 11%.

CONCLUSIONS

Severe type 7 adenovirus pneumonia in children has severe conditions, with a high incidence rate of complications and a high mortality rate, so it should be diagnosed and treated as early as possible.

[Clinical features of severe type 7 adenovirus pneumonia: an analysis of 45 cases]

OBJECTIVE

To study the clinical features of severe type 7 adenovirus pneumonia in children.

METHODS

A retrospective analysis was performed for the clinical data of children who were diagnosed with severe type 7 adenovirus pneumonia from February to June, 2019.

RESULTS

Among the 45 children, the male/female ratio was 3:2 and the median age was 14 months. All children had repeated fever, cough, and pulmonary moist rales, and the mean duration of fever was 14±4 days. The median time from fever to dyspnea was 8 days, and the time from fever to mechanical ventilation was 11.6±2.5 d. There was no significant increase in white blood cell count, with neutrophils as the main type. There were slight reductions in hemoglobin and albumin, while platelet and fibrinogen remained normal. There were increases in aspartate aminotransferase, lactate dehydrogenase, procalcitonin, and C-reaction protein. The detection rate of mixed pathogens was 84%. Effusion in both lungs was the major change on chest imaging (64%). Bronchoscopic manifestations were endobronchitis, tracheomalacia, and plastic bronchitis. The incidence rate of respiratory complications was 100%, and extrapulmonary complications mainly involved the circulatory system (47%), digestive system (36%), and nervous system (31%). Among the 45 children, 16 were administered with 400 mg/kg intravenous immunoglobulin (IVIG) daily for 5 days, with a mean duration of fever of 16±5 days, and 29 were administered with 1 g/kg IVIG daily for 2 days, with a mean duration of fever of 13±4 days; there was a significant difference in the mean duration of fever between the two groups (P=0.046). The overall mortality rate was 11%.

CONCLUSIONS

Severe type 7 adenovirus pneumonia in children has severe conditions, with a high incidence rate of complications and a high mortality rate, so it should be diagnosed and treated as early as possible.

Clinico-Pathological Study of Adenovirus Associated with Respiratory Infections in Children

Background:

Adenovirus is associated with respiratory tract infections in children worldwide. However, there is insufficient data about adenovirus infections in Egyptian children and the genotypes present in this infection.

Objective:

The aim of the present study was to investigate the prevalence of adenovirus and its genotypes in respiratory tract infection in children by real-time Polymerase Chain Reaction (PCR).

Methods:

The study was a cross-sectional study that included 100 children complaining of respiratory tract infections signs and symptoms. Laboratory investigation for adenovirus included real-time polymerase chain reaction and genotypes detection by Multiplex Polymerase Chain Reaction (PCR).

Results:

Adenovirus was detected by PCR for fiber gene in 11% with genotype 3 in 6 samples (54.5%) and genotype 7 in 5 samples (45.5%) positive for adenovirus by Multiplex PCR. The main presenting symptoms and signs in children with adenovirus detected by PCR were cough, fever, wheezing, and croups (90.9%, 81.1%, 63.6%, and 63.6%, respectively). The diagnosis in children with adenovirus was pneumonia in 72.7% and bronchitis in 27.7%. There were statistically insignificant differences in demographic, clinical, and hematological parameters between children with adenovirus and children negative to adenovirus by PCR.

Conclusion:

The clinical characteristics of respiratory infections with adenovirus vary upon the age of the patients and the immune status. Therefore, there is a requirement for an extensive study of adenovirus in respiratory infections in children with different ages and immune status.

Plastic bronchitis due to adenoviral infection: a case report

Background

Plastic bronchitis (PB) frequently occurs as a serious postoperative complication of the Fontan procedure. The definitive causes of PB are unknown.

Case presentation

Herein, we report a pediatric case of PB secondary to adenoviral infection. A 4-year-old girl was admitted to the general pediatric ward for cough since 2 weeks and fever since 11 days. Consolidated lesions were noted in the right upper and both lower lung lobes. Extracorporeal membrane oxygenation was performed because the patient’s respiratory failure remained unalleviated despite the use of a ventilator. Bronchial dendritic casts were extracted using flexible bronchoscopy, and the patient’s breathing improved. Pathological examination of the dendritic cast confirmed the diagnosis of type I PB. The exfoliated cells of sputum and cells from bronchoalveolar lavage fluid were positive for adenoviral antigen. Human adenovirus 7 was detected by next-generation sequencing of the bronchoalveolar lavage fluid. The patient recovered and was discharged 39 days after admission without recurrence of cough or wheezing.

Conclusions

PB due to human adenovirus 7 infection should be considered in children with persistent respiratory failure. Flexible bronchoscopy should be performed early to confirm diagnosis and to remove any airway obstruction.

Clinical manifestations and risk factors of adenovirus respiratory infection in hospitalized children in Guangzhou, China during the 2011-2014 period

To evaluate epidemiology and risk factors of severe adenovirus respiratory infection in hospitalized children in Guangzhou, China.A retrospective review study was conducted, and 542 children hospitalized for adenovirus respiratory infection, were included from January 2011 to December 2014. Patients were younger than 14 years. Disease severity was classified into severe and mild. Laboratory tests and clinical characteristics were analyzed for risk factors of adenovirus respiratory infection by multivariable logistic regression.Among these 542 children, 92.1% were aged < 6 years. Clinical diagnoses were upper respiratory infections in 11.6%, bronchiolitis in 16%, and mild pneumonia in 62.0% of children. Severe pneumonia rate was 10.3% (56/542) with a mortality rate of 0.9% (5/542). The cohort comprised 542 patients; 486 patients with mild adenovirus respiratory infection and 56 patients with severe adenovirus respiratory infection. Multivariable logistic regression was used to confirm associations between variables and adenovirus respiratory infection, after age and gender adjustment. Hospital stay, still significantly associated with adenovirus respiratory infection. Patients with longer hospital stay (odds ratio [OR] = 1.20, 95% confidence interval [CI]: 1.13-1.28, P < .001), lower LYMPH (OR = 0.73 95% CI: 0.55-0.99, P = .039), and increased LDH (OR = 1.002, 95% CI: 1.001-1.003, P =  .001) had a higher risk of severe adenovirus respiratory infection.Adenovirus is a major pathogen in hospitalized children with respiratory infection. High serum LDH level and low lymphocyte count could be used as predictors of adenovirus respiratory infection severity in children.

Molecular and clinical characterization of human adenovirus associated with acute respiratory tract infection in hospitalized children

•

3.71% of children with ARTI exhibited HAdV positive.

•

HAdV-2, HAdV-3 and HAdV-7 were the predominant types identified from ARTI children.

•

74.85% of HAdV were co-detected with other respiratory pathogens, most commonly HRV.

•

The co-detection rate of HAdV-C was significant higher than those of HAdV-B.

•

HAdV-7 positive children may not present more severe clinical outcome.

Background

Human adenovirus (HAdV) is a common pathogen in children that can cause acute respiratory tract infection (ARTI), but the molecular epidemiological and clinical information relating to HAdV among hospitalized children with ARTI are few reported in China.

Objectives

To evaluate the epidemiological, clinical, and molecular characteristics of HAdV infections among hospitalized children with ARTI in Hebei, Northern China from June 2017 to May 2018.

Study design

A 12-month longitudinal, retrospective study on HAdV, typed by nested polymerase chain reaction targeting the hexon gene’s hypervariable region (typing was merely performed by sequencing of the hexon neutralization epitope and thus genotypes could not be identified unequivocally), associated with ARTI was performed. The epidemiological and clinical data of different types of HAdV were analyzed using statistical product and service solutions (SPSS) 21.0 software.

Results

HAdV was detected in 330 (3.71%) of the 8906 specimens, with most (88.48%, 292/330) HAdV-positives cases detected among children < 3 years old. HAdV were detected throughout the year with a higher prevalence in spring. 11 types were identified, with HAdV-2 (33.33%, 110/330) as the predominant type, followed by HAdV-3 (21.21%, 70/330) and HAdV-7 (13.94%, 46/330). Of the 330 HAdV-positive specimens, 247 (74.85%) were co-detected with other respiratory pathogens, most commonly rhinovirus (HRV) (58.7%, 145/247). Additionally, patients with HAdV-7 positive had longer duration of fever than HAdV-2 or -3 positive patients.

Conclusions

During the study period, HAdV-2, HAdV-3 and HAdV-7 were the predominant types identified from children with ARTI in Hebei Province. Pediatric patients with HAdV-7 positive may not present more severe clinical outcome except a longer duration of fever.

Perspective on Adenoviruses: Epidemiology, Pathogenicity, and Gene Therapy

Human adenoviruses are large (150 MDa) doubled-stranded DNA viruses that cause respiratory infections. These viruses are particularly pathogenic in healthy and immune-compromised individuals, and currently, no adenovirus vaccine is available for the general public. The purpose of this review is to describe (i) the epidemiology and pathogenicity of human adenoviruses, (ii) the biological role of adenovirus vectors in gene therapy applications, and (iii) the potential role of exosomes in adenoviral infections.

Comparative study of clinical and epidemiological characteristics of major pediatric adenovirus epidemics in southern Taiwan

Background

Human adenoviruses (HAdV) are important pathogens of pediatric respiratory tract infections in Taiwan. There were two major HAdV epidemics in southern Taiwan in 2011 and 2014, respectively.

Methods

The demographic, clinical characteristics, and risk factors for hospitalization of pediatric patients with HAdV infection in the two outbreaks were retrospectively compared. The epidemic was defined as > 7% HAdV detection rate for six consecutive weeks. HAdV infection was defined as positive HAdV isolates from respiratory tract specimens. HAdV genotype was determined by PCR-based hexon gene sequencing.

Results

A total of 1145 pediatric patients were identified (635 cases in 2011; 510 cases in 2014). HAdV genotype 3 and 7 contributed to both epidemics, although the proportion of HAdV3 decreased significantly (64.7% in 2011 to 25.5% in 2014, p < 0.001) and was replaced by other genotypes (type 1, 4, and 6) in the 2014 epidemic. Among the hospitalized patients, there were more patients hospitalized with bronchopneumonia/or pneumonia in the 2011 epidemic (10.6% vs 5.1%, p < 0.001), while more patients hospitalized with acute pharyngitis/pharyngoconjunctival fever (63.9% vs. 38.6%, p < 0.001) in the 2014 epidemic. In both epidemics, hospitalized patients had higher WBC and C-reactive protein (CRP) levels than non-hospitalized patients. Using multivariate regression analysis, underlying disease and elevated CRP levels were independent risk factors for hospitalization in both epidemics.

Conclusion

There were significant differences in clinical, viral characteristics and risk factors of hospitalization between the 2011 and 2014 epidemics. Understanding changes in the epidemiological and clinical characteristics of HAdV epidemics is important from a public health perspective.

[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.

Temporal dynamics of Human mastadenovirus species in cases of respiratory illness in southern Brazil

Human mastadenovirus (HAdV) genus is related to several diseases, among them upper and lower respiratory tract illness. HAdV species B, C, D, and E are mainly associated with respiratory infections. The goal of this work was to identify the HAdV species associated with respiratory infections in hospitalized patients from southern Brazil. Samples were collected from 1996 to 2004 and 2011 to 2017. During this period, 28,524 samples were collected, and 9983 were positive for respiratory viruses, being 435 for HAdV. From these 435 samples, 57 were selected for characterization of HAdV species. For screening the presence of HAdV, a partial sequence of the DNA polymerase gene (DNApol gene) was amplified by nested PCR. Partial nucleotide sequencing was performed in positive samples, and HAdV (DNApol gene) was detected in 53 samples: species B (28; 49.1%), C (16; 28.0%), D (2; 3.5%), E (5; 8.7%), and untyped (2; 3.5%). Specie D was found only in 2017 and specie E in 2011 and 2012. The age of the patients ranged from < 1 to 81 years old, and 62.3% were male. No relationship between gender or age and identified HAdV species were observed. In addition, in the period of 2013-2017, 18 samples from patients who died were analyzed: 11 were related to species B, 4 to C, and 2 to D and 1 remained untyped. Circulation of HAdV species D and E varied over the years, but species B and C were present throughout the evaluated period. In addition, respiratory infections by HAdV affect elderly and children mainly.

Human adenovirus type 7 infection causes a more severe disease than type 3

Background

Human adenovirus type 3 (HAdV-3) and 7 (HAdV-7) cause significant morbidity and develop severe complications and long-term pulmonary sequelae in children. However, epidemiologic reports have suggested that nearly all highly severe or fatal adenoviral diseases in children are associated with HAdV-7 rather than HAdV-3. Here, we conduct in-depth investigations to confirm and extend these findings through a comprehensive series of assays in vitro and in vivo as well as clinical correlates.

Methods

A total of 8248 nasopharyngeal aspirate (NPA) samples were collected from hospitalized children with acute respiratory infections in Children’s Hospital of Chongqing Medical University from June 2009 to May 2015. Among 289 samples that tested positive for HAdVs, clinical data of 258 cases of HAdV-3 (127) and HAdV-7 (131) infections were analyzed. All HAdV-positive samples were classified by sequencing the hexon and fiber genes, and compared with clinical data and virological assays. We also performed in vitro assays of virus quantification, viral growth kinetics, competitive fitness, cytotoxicity and C3a assay of the two strains. Mouse adenovirus model was used to evaluate acute inflammatory responses.

Results

Clinical characteristics revealed that HAdV-7 infection caused more severe pneumonia, toxic encephalopathy, respiratory failure, longer mean hospitalization, significantly lower white blood cell (WBC) and platelet counts, compared to those of HAdV-3. In cell culture, HAdV-7 replicated at a higher level than HAdV-3, and viral fitness showed significant differences as well. HAdV-7 also exhibited higher C3a production and cytotoxic effects, and HAdV-7-infected mice showed aggravated pathology and higher pulmonary virus loads, compared to HAdV-3-infected mice. Macrophages in BALF remained markedly high during infection, with concomitant increase in pro-inflammatory cytokines (TNF-α, IL-1β, IFN-γ, and IL-6), compared HAdV-3 infection.

Conclusions

These results document that HAdV-7 replicates more robustly than HAdV-3, and promotes an exacerbated cytokine response, causing a more severe airway inflammation. The findings merit further mechanistic studies that offer the pediatricians an informed decision to proceed with early diagnosis and treatment of HAdV-7 infection.

New and Emerging Infections of the Lung

In this era of rapid globalization and frequent travel, emerging viral infections have gained an immense potential to spread at an unprecedented speed and scale compared with the past. This poses a significant challenge to coordinated international efforts in global surveillance and infection control.

Significantly, respiratory viral infections, spread mostly via droplet transmission, are extremely contagious and have caused significant morbidity and mortality during outbreaks in the last decade. Molecular diagnostics via reverse transcriptase polymerase chain reaction (RT-PCR) have been key in the rapid diagnosis of most of these viral infections. However, a high index of suspicion and early institution of appropriate isolation measures remain as the mainstay in the control and containment of the spread of these viral infections. Although treatment for most of the viral infections remains supportive, efficacious antiviral agents against influenza infections exist.

The infections discussed in this chapter include those first described in the 2000s: Middle East respiratory syndrome coronavirus (MERS-CoV) and metapneumovirus and rhinovirus C as well as those that have been described in the past but have reemerged in the last decade in outbreaks resulting in significant morbidity and mortality, including adenovirus, influenza virus, and enterovirus D68 (EV-D68).

Epidemiology, clinical presentation and respiratory sequelae of adenovirus pneumonia in children in Kuala Lumpur, Malaysia

Objectives

To describe the severity, human adenovirus (HAdV) type and respiratory morbidity following adenovirus pneumonia in children.

Methodology

Retrospective review of children under 12 years of age, admitted with HAdV pneumonia, between January 2011 and July 2013, in a single centre in Malaysia. HAdV isolated from nasopharyngeal secretions were typed by sequencing hypervariable regions 1–6 of the hexon gene. Patients were reviewed for respiratory complications.

Results

HAdV was detected in 131 children of whom 92 fulfilled inclusion criteria. Median (range) age was 1.1 (0.1–8.0) years with 80% under 2 years. Twenty percent had severe disease with a case-fatality rate of 5.4%. Duration of admission (p = 0.02) was independently associated with severe illness. Twenty-two percent developed respiratory complications, the commonest being bronchiolitis obliterans (15.2%) and recurrent wheeze (5.4%). The predominant type shifted from HAdV1 and HAdV3 in 2011 to HAdV7 in 2013. The commonest types identified were types 7 (54.4%), 1(17.7%) and 3 (12.6%). Four out of the five patients who died were positive for HAdV7. Infection with type 7 (OR 8.90, 95% CI 1.32, 59.89), family history of asthma (OR 14.80, 95% CI 2.12–103.21) and need for invasive or non-invasive ventilation (OR 151.84, 95% CI 9.93–2.32E) were independent predictors of respiratory complications.

Conclusions

One in five children admitted with HAdV pneumonia had severe disease and 22% developed respiratory complications. Type 7 was commonly isolated in children with severe disease. Family history of asthma need for invasive or non-invasive ventilation and HAdV 7 were independent predictors of respiratory complications.

Comparative evaluation of a laboratory-developed real-time PCR assay and RealStar® Adenovirus PCR Kit for quantitative detection of human adenovirus

Background

Human adenoviruses are common causes of community-acquired respiratory tract and enteric infections. Severe disseminated infections with high mortality rates may be seen in immunocompromised individuals. An accurate and cost-effective quantitative assay is essential not only for laboratory diagnosis of adenoviral infections, but also for monitoring of response to antiviral treatment. The diagnostic performance of an in-house quantitative polymerase chain reaction assay was compared to a commercial system.

Methods

The analytical sensitivity, specificity, linearity, precision and accuracy of an in-house adenovirus quantitative polymerase chain reaction assay were evaluated against the RealStar® Adenovirus PCR Kit (Altona Diagnostics GmbH, Hamburg, Germany), using 122 clinical specimens and 18 proficiency testing samples.

Results

Linear regression analysis of the quantitative results by the in-house assay showed the dynamic range from 2.60 to 9 log₁₀ (plasma) and 2.94 to 9 log₁₀ (viral transport medium) copies/mL, with the coefficient of determination (R²) of 0.996 and 0.998, respectively. A dilution series demonstrated the limits of detection and lower limits of quantification for plasma were 2.06 log₁₀ and 2.60 log₁₀ copies/mL and those for viral transport medium were 2.31 log₁₀ and 2.94 log₁₀ copies/mL respectively. The precision of the in-house assay was highly reproducible among runs with coefficients of variance ranging from 0.07 to 3.21% for plasma and 0.17% to 2.11% for viral transport medium. A comparison of 52 matched samples showed an excellent correlation between the quantitative viral loads measured by the in-house assay and the RealStar® Adenovirus PCR Kit (R² = 0.984), with an average bias of − 0.16 log₁₀ copies/mL.

Conclusions

The in-house adenovirus assay is a sensitive and reliable assay with lower cost for the detection and quantification of adenoviral DNA when compared to the RealStar® Adenovirus PCR Kit.

Electronic supplementary material

The online version of this article (10.1186/s12985-018-1059-7) contains supplementary material, which is available to authorized users.

Molecular epidemiology and clinical features of adenovirus infection in Taiwanese children, 2014

BACKGROUND/PURPOSES

Human adenovirus (HAdV) infection is prevalent and has an important clinical impact on children. We aim to investigate the molecular epidemiology of HAdV infection and discover the correlations between clinical features and HAdV species in an HAdV outbreak of 2014.

METHODS

This is a retrospective study, enrolling patients under 19 years of age with HAdV infection at the National Taiwan University Hospital in 2014. We gathered the demographic and clinical data, carried out molecular typing and constructed a phylogenetic tree. Statistical analyses were performed in terms of HAdV species and hospitalization.

RESULTS

A total of 531 patients with HAdV infection were identified. HAdV-B accounted for the largest proportion (n = 387, 73%). On average, patients infected with HAdV-E were oldest, whereas those with HAdV-C infection were youngest (p < 0.001). Patients with HAdV-B (HAdV-3) infection were associated with a lower incidence of co-infection with other viruses (p < 0.001). Complications occurred in 203 (38%) patients. There were 149 (28%) patients requiring hospitalization. The risk factors for hospitalization included underlying neurological abnormalities, prematurity and the diagnosis of pneumonia. Five patients (1%) had severe HAdV infection requiring intensive care; all of them fully recovered. The phylogenetic study showed that the partial hexon genes of HAdV-1, HAdV-3, HAdV-4 and HAdV-5 remain stable over time.

CONCLUSION

We established the molecular epidemiology of HAdV infection and demonstrated the relationship between clinical features and HAdV species.