Epidemiology of Adenovirus Pneumonia and Risk Factors for Bronchiolitis Obliterans in Children During an Outbreak in Jilin, China

Low-dose heparin sodium as a protective factor against bronchiolitis obliterans formation after adenovirus infection

BACKGROUND

Adenovirus (ADV) pneumonia in children is a significant contributor to the occurrence of post-infectious bronchiolitis obliterans (BO). Heparin sodium has known anti-inflammatory, immunomodulatory, and tissue repair properties. However, its role in treating BO after ADV infection remains unclear.

METHODS

A retrospective analysis was conducted on 793 children diagnosed with ADV pneumonia and hospitalized in the southern region from January 2019 to December 2019. Among them, 307 cases were classified as single ADV pneumonia. We utilized directed acyclic graphs to analyze the causal relationships between various variables, which further helped us identify the independent and confounding variables for constructing our regression model. Propensity score matching (PSM) was also employed to control for confounding variables that could not be intervened in this study, ensuring baseline level equilibrium and correction. We utilized univariate logistic regression analysis to explore the factors influencing BO development after ADV pneumonia.

RESULTS

Among the 793 children diagnosed with ADV pneumonia, 86 cases (10.84%) progressed to BO. The proportion of heparin use was higher in the non-BO group than in the BO group after PSM. The univariate regression analysis revealed that acute respiratory failure, neurological involvement and fibrinogen (FIB) were risk factors for the development of BO in ADV pneumonia cases (OR > 1, p < 0.05), but low-dose heparin sodium treatment and hemoglobin (OR < 1, p < 0.05) exhibited protective effects against BO formation. Among the 307 children with single ADV pneumonia (excluding confounding factors), 33 cases (10.75%) developed BO. The univariate regression analysis further indicated that fever duration, acute respiratory failure and FIB were risk factors for the development of BO in single ADV pneumonia (OR > 1, p < 0.05), while low-dose heparin sodium treatment (OR < 1, p < 0.05) was protective against BO formation after a single ADV pneumonia.

CONCLUSION

Low-dose heparin sodium treatment may be a protective factor against the development of BO after ADV pneumonia infection.

Chronic Lung Disease after Hospitalization with Adenovirus or Respiratory Syncytial Virus

BACKGROUND

Studies have shown a high risk of interstitial lung disease after hospitalization with adenovirus (AdV) and a high risk of asthma after hospitalization with respiratory syncytial virus (RSV).

OBJECTIVE

To clarify to what extent children hospitalized with respiratory tract infection caused by AdV or RSV develop pulmonary disease.

DESIGN

Register-based cohort study.

METHODS

Data on infections with AdV and RSV were coupled to data on asthma, asthma medication, bronchiectasia and interstitial lung disease, including bronchiolitis obliterans, during a follow-up time of 15-20 years. An age-matched control group was also generated. The risks of subsequent lung disease and/or having received asthma medication and hazard ratios (HRs) for asthma between the index groups and the control group were computed.

FINDINGS

In total 4704 children were included. Less than 5 cases of interstitial lung disease or bronchiectasia were found in any group. After hospitalization with AdV or RSV, the risk of acquiring an asthma diagnosis or having received asthma medication during follow-up was 29% and 65%, respectively, for AdV, and 22% and 51%, respectively, for RSV; corresponding to adjusted HRs of 2.16 (0.92-5.07), 2.60 (1.57-4.31), 2.87 (2.30-3.58), and 2.37 (2.07-2.71), respectively.

CONCLUSION

We could not confirm an increased risk of interstitial lung disease after infection with AdV. However, there is a considerable risk of asthma after hospitalization with AdV or RSV and with respect to RSV, the risk is higher than previously reported as expressed by the fraction having received asthma medication during follow-up.

Epidemiological characteristics and genomic analysis of respiratory adenovirus in Jining City from February 2023 to July 2024

BACKGROUND

Human adenovirus (HAdV) infection can cause high fever, pneumonia, and even death, posing a serious threat to human health. This study analyzes the epidemiological characteristics and genetic features of respiratory adenovirus in Jining City from February 2023 to July 2024.

METHODS

From February 2023 to July 2024, 3,947 throat swab specimens were collected from influenza-like illness cases at Jining First People's Hospital and Rencheng District Maternal and Child Health Hospital. Real-time fluorescent quantitative PCR was used to detect HAdV nucleic acid. Whole-genome sequencing was performed on HAdV-positive samples. Phylogenetic trees were constructed for the whole genome, Penton base gene, Hexon gene, and Fiber gene of HAdV, and protein variation sites were analyzed.

RESULTS

The HAdV positivity rate in influenza-like cases in Jining City from February 2023 to July 2024 was 3.42% (135/3947), with higher positivity rates in younger age groups. HAdV positivity rates were higher between December 2023 and July 2024, while lower between January 2023 and November 2023. Whole-genome sequencing was performed on 47 HAdV samples, revealing 38 cases of HAdV-B and 9 cases of HAdV-C, with no HAdV-E detected. HAdV-B and HAdV-C co-circulated in Jining City from February to December 2023, while HAdV-B predominated from January to July 2024. All 38 HAdV-B sequences from Jining City are HAdV-3. In the phylogenetic trees of the whole genome, Penton base gene, Hexon gene, and Fiber gene of HAdV-B, all 38 HAdV-B strains from Jining City are located in the same evolutionary branch as the Chinese HAdV-3 candidate vaccine strain Guangzhou01. Compared to Guangzhou01, the RGD motif in Penton base and antigenic epitopes in Hexon of the 38 HAdV-B strains from Jining remained unchanged. Among the 9 HAdV-C sequences from Jining, 4 were identified as HAdV-104 and 5 as HAdV-108. The RGD motif in Penton base protein and receptor-binding sites in Fiber protein remained unchanged in all 9 HAdV-C sequences.

CONCLUSIONS

From February 2023 to July 2024, HAdV in Jining City primarily circulated among younger age groups in influenza-like illness cases, with no apparent seasonal pattern. Enhanced surveillance of HAdV and accelerated development and marketing of HAdV vaccines are necessary.

Outbreak of Post-Infectious Bronchiolitis Obliterans (PIBO) After Adenovirus Infection: A Case Series and Review of the Literature

BACKGROUND

Post-infectious bronchiolitis obliterans (PIBO) is a rare chronic pediatric pulmonary disease characterized by irreversible fibrotic narrowing of the small airways. Treatment options remain uncertain with limited success.

OBJECTIVE

To delineate the characteristics of patients diagnosed with PIBO in Ljubljana (Slovenia) and Trieste (Italy) in 2023.

METHODS

We retrospectively assessed clinical records of PIBO patients from January to December 2023, capturing data on initial viral infection, clinical presentation, radiological features, treatments, and outcomes.

RESULTS

In 2023, 11 patients were identified, contrasting with only 6 cases in the previous 7 years. Common symptoms and signs included tachypnea, chronic wet cough, and diffuse crackles following adenovirus pneumonia. Most patients were previously healthy. Chest CT findings confirmed the diagnosis in all cases. Bronchoalveolar lavage showed elevated levels of neutrophils (46% to 90% of cells), and biopsies performed in 6 patients indicated predominantly lymphocytic inflammatory infiltrate and bronchiolar fibrosis. Nocturnal pulse oximetry revealed reduced mean SpO2 (median: 96.5% Q1: 93%, Q3: 98%) and reduced lower values (median: SpO2 89% Q1: 87%, Q3: 92.5%) with an increased oxygen desaturation index (1.1 to 11.2 events/hour). Treatment involved methylprednisolone (20-30 mg/kg) for three consecutive days monthly for 6 months, resulting in clinical improvement in nine patients and radiological improvement in seven patients.

CONCLUSIONS

The post-pandemic surge in PIBO cases may stem from viral ecology changes, immunologic factors, and/or adenovirus genotypes, highlighting the need for further research into its etiology and management strategies.

Risk factors for bronchiolitis obliterans development in children after Mycoplasma pneumoniae pneumonia: a retrospective study of 981 patients

BACKGROUND

Bronchiolitis obliterans (BO) is a rare and severe chronic pulmonary condition in children following an injury to lower respiratory tract lesion. Mycoplasma pneumoniae (M. pneumoniae) is the second etiology of post-infectious bronchiolitis obliterans (PIBO). The aim of this study was to determine risk factors for PIBO development in children after M. pneumoniae pneumonia.

METHODS

This retrospective study enrolled 981 children admitted to Beijing children's hospital due to M. pneumoniae pneumonia between January 2016 and December 2022. The medical records of the PIBO and non-PIBO groups, including demographic, clinical, radiologic, and laboratory data were analyzed by multivariate logistic regression to reveal PIBO development-associated risk factors.

RESULTS

Seventy-two of the study patients developed PIBO after M. pneumoniae pneumonia. Multivariate analysis showed that large lobar consolidation (OR 4.06, 95% CI 1.18-14.03), diffuse bronchiolitis (OR 11.78, 95% CI 3.28-42.22), co-infection (OR 3.65, 95% CI 1.60-8.33), atopic conditions (OR 12.32, 95% CI 5.2-29.11), bronchial mucus plug (OR 2.48, 95% CI 1.10-5.58), CPR (OR 1.01, 95% CI 1.00-1.02), mechanical ventilation (OR 2.95, 95% CI 1.00-8.67), and duration of fever (OR 1.19, 95% CI 1.05-1.37) were significantly associated with development of PIBO after M. pneumoniae pneumonia.

CONCLUSIONS

In children with M. pneumoniae pneumonia, large lobar consolidation, diffuse bronchiolitis, co-infections, atopic conditions, bronchial mucus plug, CRP, mechanical ventilation, and duration of fever appeared as prominent independent risk factors for PIBO. Timely application of HRCT could provide a basis for the early prediction of PIBO development in children.

Risk Factors for Developing Adenovirus-Associated Post-Infectious Bronchiolitis Obliterans

BACKGROUND

Risk factors for progression of adenovirus (AdV)-associated bronchiolitis (AdV-B) to post-infectious bronchiolitis obliterans (PIBO) are poorly defined. We aimed to investigate this in a multicenter cohort.

METHODS

A multicenter hospital-based analysis included children admitted with AdV-B in Jerusalem during 2016-2022. A case-control analysis included AdV-PIBO patients in Jerusalem during 2005-2023. Cases were compared to randomly assigned controls admitted with AdV-B without progression to AdV-PIBO. Multivariate analysis with logistic regression was used.

RESULTS

The annual incidence of AdV-B admissions and AdV-PIBO increased during 2016-2022, during which 1522 children were admitted with AdV-B and 8 developed AdV-PIBO (0.5%). Of 30 AdV-PIBO cases identified during 2005-2023, available data were compared for 25 of them (72% boys; mean age ± standard deviation 1.2 ± 0.8 years) and 139 controls (66% boys; mean age 1.0 ± 0.6 years, p = 0.5 for age). Jewish ethnicity was more common in the AdV-PIBO versus control group (92% vs. 66%, p = 0.009), as were oxygen supplementation (84% vs. 45%, p < 0.001), noninvasive ventilation (20% vs. 4%, p = 0.004), consolidations on chest X-ray (44% vs. 19%, p = 0.011), and lymphopenia (92% vs. 46%, p < 0.001). Combining Jewish ethnicity, lymphopenia, consolidations, and prolonged admission as independent risk factors yielded positive and negative predictive values of 68.8% and 90.5%, respectively.

CONCLUSION

These findings emphasize the urgent need for targeted preventive and management strategies. The identification of Jewish ethnicity as a risk factor may imply a genetic contribution to Adv-PIBO risk.

Clinical features and risk factors for development of post-infectious bronchiolitis obliterans in children

BACKGROUND

Post-infectious bronchiolitis obliterans (PIBO) is a severe form of chronic obstructive lung disease secondary to severe respiratory tract infections. Knowledge of pediatric PIBO development-associated risk factors may improve selection of appropriate early therapeutic interventions.

OBJECTIVE

The aim of this study was to describe the clinical characteristics of children diagnosed with PIBO, and identify the risk factors for development of PIBO after adenovirus pneumonia.

METHODS

First, a retrospective observational study was performed of 308 pediatric patients with PIBO (ages < 5 years) that revealed high frequencies of non-invasive/invasive ventilation, co-infection, and atopic conditions. Subsequently, we retrospectively reviewed 131 patients (ages < 5 years) with adenovirus pneumonia who developed BO (included among the 308 children) or not. Logistic regression analysis revealed PIBO development-associated risk factors.

RESULTS

Respiratory symptoms of 308 patients (median age of 18 months, range: 12-54 months; male predominance of 3.7:1) included wheezing (71%), dyspnea (66%), tachypnea (23%), and hypoxemia (18%). Etiologic agents (predominantly adenovirus, Mycoplasma pneumoniae) were detected in 236 patients, of whom 137 had co-infections. Notably, atopic disease history (of patients and/or family members) was associated with 78% of patients, and 15% of patients diagnosed with asthma before, at the time of PIBO diagnosis. In a subsequent study of 131 adenovirus pneumonia patients, multivariate analysis showed that co-infection (OR 4.20, 95% CI 1.29 to 13.63), atopic conditions (OR 29.67, 95% CI 12.16 to 81.67), and duration of fever (OR 1.42, 95% CI 1.10 to 1.83) were independent risk factors for PIBO development following adenovirus pneumonia.

CONCLUSIONS

Atopic conditions, co-infections, and duration of fever were identified as risk factors for pediatric post-infectious BO development following adenovirus pneumonia, and PIBO may overlap with asthma, warranting early aggressive treatment and further research to elucidate roles of atopic conditions in BO development.

Risk factors for bronchiolitis obliterans complicating adenovirus pneumonia in children: a meta-analysis

Objective

To preliminarily explore the risk factors for post-infectious bronchiolitis obliterans (PIBO) complicating adenovirus pneumonia (ADVP) in children through a meta-analysis.

Methods

A systematic search was conducted on three English-language databases (PubMed, Web of Science and The National Library of Medicine) and two Chinese-language databases (China National Knowledge Infrastructure and the Wanfang Database) between database inception and 1 January 2023. Data analysis was conducted using Stata 15.1 software.

Results

A total of 10 articles, reporting 14 risk factors, were included in the analysis, with 8 risk factors taken into consideration. Through the meta-analysis, 5 risk factors were identified for PIBO complicating ADVP in paediatric patients: hypoxaemia [odds ratio (OR) = 9.37, 95% CI: 4.22, 20.77, p < 0.001], persistent wheezing (OR = 4.65, 95% CI: 2.20, 9.82, p < 0.001), mechanical ventilation (OR = 3.87, 95% CI: 2.37, 6.33, p < 0.001), length of hospital stay (LoHS) (OR = 1.25, 95% CI: 1.09, 1.43, p < 0.001) and fever duration (OR = 1.08, 95% CI: 1.02, 1.14, p = 0.009).

Conclusion

Existing evidence suggests that hypoxaemia, persistent wheezing, mechanical ventilation, LoHS and fever duration are risk factors for PIBO complicating ADVP in children. These findings underscore the need for enhanced assessment and management in clinical practice. This study may provide such a clinical prediction model from the identified 5 risk factors for PIBO and offer valuable insights for preventing bronchiolitis obliterans in children with ADVP.

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.

Risk factors and prediction models for bronchiolitis obliterans after severe adenoviral pneumonia

Severe adenoviral pneumonia (SAP) can cause post-infectious bronchiolitis obliterans (PIBO) in children. We aimed to investigate the relevant risk factors for PIBO and develop a predictive nomogram for PIBO in children with SAP. This prospective study analysed the clinical data of hospitalised children with SAP and categorised them into the PIBO and non-PIBO groups. Least absolute shrinkage and selection operator (LASSO) regressions were applied to variables that exhibited significant intergroup differences. Logistic regression was adopted to analyse the risk factors for PIBO. Additionally, a nomogram was constructed, and its effectiveness was assessed using calibration curves, C-index, and decision curve analysis. A total of 148 hospitalised children with SAP were collected in this study. Among them, 112 achieved favourable recovery, whereas 36 developed PIBO. Multivariable regression after variable selection via LASSO revealed that aged < 1 year (OR, 2.38, 95% CI, 0.82-6.77), admission to PICU (OR, 24.40, 95% CI, 7.16-105.00), long duration of fever (OR, 1.16, 95% CI, 1.04-1.31), and bilateral lung infection (OR, 8.78, 95% CI, 1.32-195.00) were major risk factors for PIBO. The nomogram model included the four risk factors: The C-index of the model was 0.85 (95% CI, 0.71-0.99), and the area under the curve was 0.85 (95% CI, 0.78-0.92). The model showed good calibration with the Hosmer-Lemeshow test (χ2 = 8.52, P = 0.38) and was useful in clinical settings with decision curve analysis.

CONCLUSION

Age < 1 year, PICU admission, long fever duration, and bilateral lung infection are independent risk factors for PIBO in children with SAP. The nomogram model may aid clinicians in the early diagnosis and intervention of PIBO.

WHAT IS KNOWN

• Adenoviruses are the most common pathogens associated with PIBO. • Wheezing, tachypnoea, hypoxemia, and mechanical ventilation are the risk factors for PIBO.

WHAT IS NEW

• Age < 1 year, admission to PICU, long duration of fever days, and bilateral lung infection are independent risk factors for PIBO in children with SAP. • A prediction model presented as a nomogram may help clinicians in the early diagnosis and intervention of PIBO.

Clinical features and prediction of risk factors for severe adenovirus pneumonia in children

Background

Adenoviral infections are most likely to invade the respiratory tract, and the clinical manifestations of the infections are varied; in severe cases, they may cause systemic multi-system damages and so on. At present, early clinical differential diagnosis is difficult under the existing testing methods, so it is important to analyze its clinical characteristics and risk factors for early identification of critical status and early and rational treatment.

Methods

The clinical data of 202 children with adenovirus pneumonia admitted to Tianjin Children's Hospital from January 2019 to December 2021 were retrospectively analyzed. According to the evaluation criteria for severe pneumonia, they were divided into a severe group (77 cases) and a non-severe group (125 cases). The clinical characteristics, complications, and laboratory data of the 2 groups were collected for statistical analysis, and then significant factors were analyzed by receiver operating characteristic curve (ROC) and binary logistic regression.

Results

Among the 202 children with adenovirus pneumonia, there were 108 males and 94 females. The children ranged in age from 2 months to 13 years. The duration of fever, incidence of wheezing, neutrophil ratio (NEUT%), and serum ferritin (SF) levels were significantly higher in the severe group than in the non-severe group (χ2/Z/P=-9.173/<0.001, 5.469/0.019, 5.831/<0.001, -3.845/<0.001). The incidences of liver injury, electrolyte disturbance, and coagulation dysfunction in the severe group were significantly higher than those in the non-severe group (χ2/Z/P=0.001/0.001, 28.208/0.001, 32.079/0.001). Logistic regression combined with ROC curve analysis suggested that fever duration >4.50 days, with wheezing, NEUT% ≥47.60, and SF ≥139.60 ng/mL were risk factors for developing severe adenovirus pneumonia in children [odds ratio (OR) (95% CI): 1.394 (1.230-1.581), 3.673 (1.246-10.828), 1.034 (1.001-1.067), 1.004 (1.001-1.008)].

Conclusions

Studies have shown that the fever associated with severe adenovirus pneumonia has a long duration, and that severe clinical manifestations and multiple complications, fever duration >4.50 days, wheezing, NEUT% ≥47.60, and SF ≥139.60 ng/mL are risk factors for severe adenovirus pneumonia.

Risk factors for the development of bronchiolitis obliterans in children after suffering from adenovirus pneumonia

Introduction

Bronchiolitis obliterans (BO) is an irreversible chronic obstructive lung disease in small airways. The aim of this study was to identify the relevant risk factors for the development of BO in children after suffering from adenovirus (ADV) pneumonia.

Methods

An observational cohort study that included 112 children suffering from ADV pneumonia in our institution from March 2019 to March 2020 was performed. We divided the children into a BO group and a non-BO group based on whether they did develop BO or not. Univariate analysis and multivariate logistic regression analysis were applied to identify risk factors for the development of BO. The prediction probability model was evaluated by receiver operating characteristic (ROC) curve analysis.

Results

Twenty-eight children (25%) did develop BO after suffering from ADV pneumonia, while 84 children did not. Respiratory support (OR 6.772, 95% CI 2.060-22.260, P = 0.002), extended length of wheezing days (OR 1.112, 95% CI 1.040-1.189, P = 0.002) and higher lactic dehydrogenase (LDH) levels (OR 1.002, 95% CI 1.000-1.003, P = 0.012) were independently associated with the development of BO. The predictive value of this prediction probability model was validated by the ROC curve, with an area under the curve of 0.870 (95% CI 0.801-0.939, P < 0.001), a standard error of 0.035, a maximum Youden's index of 0.608, a sensitivity of 0.929, and a specificity of 0.679.

Conclusions

After suffering an ADV pneumonia, children who have needed respiratory support, had a longer length of wheezing days or had higher LDH levels are more likely to develop BO.

Clinical Characteristics and Genotyping of Pediatric Adenovirus Pneumonia Disease and Coinfection in Southeast China

Introduction: Human adenovirus (HAdV) is a common pathogen that can cause acute respiratory infections (ARIs) in children. Adenovirus pneumonia is the most severe respiratory disease associated with HAdV. Objective: We aimed to investigate the clinical characteristics of children hospitalized with adenovirus pneumonia in Quanzhou, China, in 2019. We also sought to determine the viral genotype in these cases and explore cases associated with severe adenovirus pneumonia. Methods: We collected oropharyngeal swabs from 99 children who were hospitalized with pneumonia in Quanzhou Women and Children's Hospital, these samples were tested for the presence of HAdV. Genotyping of the viruses was performed by real-time polymerase chain reaction. Logistic regression analysis was employed to analyze risk factors related to severe adenovirus pneumonia. The epidemiological data were examined using the Statistical Package for Social Sciences software (SPSS). Results: Among the 99 patients in our study, the median age was 21 months. We observed a 4% mortality rate among those diagnosed with adenovirus pneumonia. Adenovirus pneumonia often presents as a coinfection. Lactate dehydrogenase and neutrophil percentages of WBC's were significantly increased in patients with severe adenovirus pneumonia compared with mild HAdV disease. The predominant viral genotypes identified were type 3 and type 7. Conclusions: In the Quanzhou area of southeast China, the incidence of adenovirus pneumonia was found to be high among children younger than two years old. Type 7 HAdV was identified as the primary pathogen. A long duration of fever, dyspnea and digestive system complications were risk factors for severe adenovirus pneumonia after HAdV infection. Clinical Trial Registration number: ChiCTR2200062358.

Worldwide Bronchiolitis obliterans research: A bibliometric analysis of the published literature between 2002 and 2022

Bronchiolitis obliterans (BO) is a rare and irreversible chronic respiratory disease. The diagnosis of BO is challenging, and there still needs to be specific therapies and uniform treatment guidelines available. Research on BO has grown steadily over the past 20 years, and with the continued interest of researchers in this area, a bibliometric study of BO becomes necessary. This topic aims to assess the current state of research in BO over the last 2 decades and to identify research hotspots and emerging directions. Information on BO-related articles were obtained from the Science Citation Index Expand of the Web of Science Core Collection (WOSCC [SCI-E]) database. Citespace (6.1.R6), VOSviewer (1.6.18), and the online bibliometrics website (https://bibliometric.com/) were used for bibliometric analysis mainly to include country/region, institution, author, journal, keywords, and references and to construct visual knowledge network diagrams. A total of 4153 publications from the WOSCC [SCI-E] database were included in this study. Most publications come from the United States, Japan, and Germany, which collaborate relatively more frequently. Research institutions in the United States, especially the University of Washington, published the largest number of BO-related articles. Regarding authors, Vos, R is the most productive author, while Verleden, GM is the most influential in BO. In addition, JOURNAL OF HEART AND LUNG TRANSPLANTATION is the journal with the most published articles. The most cited article is Estenne M, 2002. Based on the clustering analysis of keywords and references, the diagnosis of bronchiolitis obliterans syndrome (BOS), treatment of BOS, and risk factors of BO are the current research hotspots and future research trends. We analyzed the publication trends in BO by bibliometrics and mapped the knowledge network of major contributing countries/regions, institutions, authors, and journals. Current research hotspots were found based on the main keywords and references. The outcome may help researchers identify potential collaborators, collaborating institutions, and hot fronts in BO to enhance collaboration on critical issues and improve the diagnosis and treatment of BO.

A Diagnostic Nomogram for Early Prediction of Post-Infectious Bronchiolitis Obliterans in Severe Pneumonia

Objective

The study aimed to set up and validate a predictive nomogram for post-infectious bronchiolitis obliterans in severe pneumonia.

Methods

We retrospectively analyzed data of 228 patients diagnosed with severe pneumonia and constructed a prediction nomogram. The least absolute shrinkage and selection operator (LASSO) regression model was utilized to optimize the selection of features for the clinical characteristics of post-infectious bronchiolitis obliterans. Individual nomograms of bronchiolitis obliterans incorporating clinical factors were developed using the multivariate logistic model. The C-index, calibration plot, and decision curve analysis were used to verify the calibration, discrimination, and clinical utility. The bootstrapping method was used for the internal validation of the model.

Results

Predictors in the individualized predictive nomogram included age of patients (odds ratio [OR], 0.994; 95% confidence interval; [CI], 0.990-0.998), length of stay (OR, 1.043; 95% CI: 1.015-1.073), mechanical ventilation (OR, 1.865; 95% CI: 1.236-2.817), human adenoviral infection (OR, 1.671; 95%, CI: 1.201-2.326), and the level of interleukin (IL)-2 (OR, 0.947; 95% CI: 0.901-0.955). The model discriminated reasonably well, with a C-index of 0.907 (C-index, 0.888 and 0.926) with good calibration and internal validation, which was not statistically significant by the Hosmer-Lemeshow test (P = 0.5443). Decision curve analysis showed that nomograms were useful in clinical settings.

Conclusion

In this study, a model was developed and presented as a nomogram with relatively good accuracy to help clinicians accurately and early diagnose post-infectious bronchiolitis obliterans in children with severe pneumonia.

Epidemiological Survey and Risk Factor Analysis of 14 Potential Pathogens in Golden Snub-Nosed Monkeys at Shennongjia National Nature Reserve, China

Golden snub-nosed monkeys (Rhinopithecus roxellanae) belong to Class A, the highest level of endangered primate species. Exploring the infection status of potential pathogens in golden snub-nosed monkeys is important for controlling associated diseases and protecting this species. The objective of this study was to investigate the seroprevalence for a number of potential pathogens and the prevalence of fecal adenovirus and rotavirus. A total of 283 fecal samples were collected from 100 golden snub-nosed monkeys in December 2014, June 2015, and January 2016; 26 blood samples were collected from 26 monkeys in June 2014, June 2015, January 2016 and November 2016 at Shennongjia National Reserve in Hubei, China. The infection of 11 potential viral diseases was examined serologically using an Indirect Enzyme-linked Immunosorbent Assay (iELISA) and Dot Immunobinding Assays (DIA), while the whole blood IFN-γ in vitro release assay was used to test tuberculosis (TB). In addition, fecal Adenovirus and Rotavirus were detected using Polymerase Chain Reaction (PCR). As a result, the Macacine herpesvirus-1 (MaHV-1), Golden snub-nosed monkey cytomegalovirus (GsmCMV), Simian foamy virus (SFV) and Hepatitis A virus (HAV) were detected with the seroprevalence of 57.7% (95% CI: 36.9, 76.6), 38.5% (95% CI: 20.2, 59.4), 26.9% (95% CI: 11.6, 47.8), and 7.7% (95% CI: 0.0, 84.2), respectively. Two fecal samples tested positive for Adenovirus (ADV) by PCR, with a prevalence of 0.7% (95% CI: 0.2, 2.5), and further, the amplification products were sequenced. Phylogenetic analysis revealed that they belonged to the HADV-G group. However, other pathogens, such as Coxsackievirus (CV), Measles virus (MeV), Rotavirus (RV), Simian immunodeficiency virus (SIV), Simian type D retroviruses (SRV), Simian-T-cell lymphotropic virus type 1 (STLV-1), Simian varicella virus (SVV), Simian virus 40 (SV40) and Mycobacterium tuberculosis complex (TB) were negative in all samples. In addition, a risk factor analysis indicated that the seroprevalence of MaHV-1 infection was significantly associated with old age (≥4 years). These results have important implications for understanding the health status and conservation of the endangered golden snub-nosed monkey population at Shennongjia Nature Reserve.

Construction and analysis of a nomogram prediction model for post-infectious bronchiolitis obliterans in children with adenovirus pneumonia after invasive mechanical ventilation

BACKGROUND

Post-infectious bronchiolitis obliterans (PIBO) is the most common sequelae in children with adenovirus pneumonia (ADVP). However, there are few studies on the risk factors for PIBO occurrence. This study aims to investigate the risk factors for PIBO in pediatric patients with severe ADVP, especially after invasive mechanical ventilation (IMV), as well as to build a nomogram prediction model.

METHODS

The clinical data, laboratory and imaging features, and treatment of 863 children with ADVP under 3 years old who were admitted to our hospital from January to December 2019 were retrospectively analyzed. Among them, 66 children with severe ADVP received IMV treatment. The situation and the influencing factors of PIBO in children with severe ADVP were explored, and a nomogram prediction model was constructed.

RESULTS

Among the 863 cases of ADVP, 46 cases (5.33%) developed PIBO. Duration of fever, IMV, complications, and neutrophil percentage were independent risk factors for PIBO in children with ADVP. Among the 66 patients with ADVP who underwent IMV, 33 patients (50.0%) developed PIBO. Gender, duration of fever, adenovirus (ADV) load, and mixed fungal coinfections were independent risk factors for PIBO. In the nomogram prediction model analysis, the area under the curve (AUC) was 0.857; in addition, Hosmer‒Lemeshow (H-L) detection reflected good alignment (χ2 = 68.75, P < 0.01).

CONCLUSIONS

A nomogram prediction model, which can be utilized to predict PIBO occurrence in pediatric patients with ADVP after IMV at an early time period, was successfully built.

Pneumonia in Children During the 2019 Outbreak in Xiamen, China

BACKGROUND

To understand the regional epidemiology and clinical characteristics of adenovirus pneumonia in hospitalized children during the 2019 outbreak of respiratory adenoviruses in China.

METHODS

We analyzed the epidemiologic trend of adenovirus in children hospitalized for acute lower respiratory tract infections in Xiamen in 2019. Adenovirus was identified using direct fluorescent antibody detection. During the peak seasons of adenovirus epidemic, 170 adenovirus-positive specimens were obtained for molecular typing, and the clinical data were collected.

RESULTS

Among the 9890 children hospitalized for acute lower respiratory tract infection, 609 (6.2%) were tested positive for adenovirus. The detection rate of adenovirus was significantly higher in boys than in grils (9.5% vs. 4.6%, P < 0.05). Adenovirus activity increased markedly between April and August with the prevalence of 7.3%-12.4%. During the outbreak season, type 7 accounted for 70.6%, followed by type 3 (28.8%) and type 4 (0.6%). Of the 155 cases of adenovirus pneumonia, the median age was 3.0 years (range: 4 month to 9 years), 153 (98.7%) had fever with a mean fever duration of 9.04 ± 5.52 days, 28 (16.5%) had wheezing, 93 (60%) showed segmental or lobar consolidation with atelectasis and 13 (8.4%) showed pleural effusion. Forty-six (29.6%) cases developed severe pneumonia, 7 (4.1%) required mechanical ventilation and 2 (1.2%) died. Younger age, longer duration of fever and higher fever spike were more frequently seen in severe cases (P < 0.05). Twenty-five (16.2%) had C-reactive protein ≥ 40 mg/L, and 91 (58.7%) had procalcitonin ≥ 0.25 mg/L.

CONCLUSIONS

Adenovirus types 7 and 3 caused the outbreak of adenovirus pneumonia in community children during late spring to summer in 2019 in Xiamen. The majority of adenovirus pneumonia resembles bacterial pneumonia. The incidence of severe pneumonia was high when type 7 predominantly prevailed. Adenovirus type 7 was more common in severe cases than in nonsevere cases.

A nomogram for predicting severe adenovirus pneumonia in children

Adenoviral pneumonia in children was an epidemic that greatly impacted children's health in China in 2019. Currently, no simple or systematic scale has been introduced for the early identification and diagnosis of adenoviral pneumonia. The early recognition scale of pediatric severe adenovirus pneumonia was established based on an analysis of the children's community-acquired pneumonia clinical cohort. This study analyzed the clinical data of 132 children with adenoviral pneumonia who were admitted to the Children's Hospital of Nanjing Medical University. The clinical parameters and imaging features were analyzed using univariate and multivariate logistic regression analyses. A nomogram was constructed to predict the risk of developing severe adenovirus pneumonia in children. There were statistically significant differences in age, respiratory rate, fever duration before admission, percentage of neutrophils and lymphocytes, CRP, ALT, and LDH between the two groups. Logistic regression analysis was conducted using the R language, and respiratory rate, percentage of neutrophils, percentage of lymphocytes, and LDH were used as scale indicators. Using the ROC curve, the sensitivity and specificity of the scale were 93.3% and 92.1%. This scale has good sensitivity and specificity through internal verification, which proves that screening for early recognition of severe adenovirus pneumonia can be realized by scales. This predictive scale helps determine whether a child will develop severe adenovirus pneumonia early in the disease course.

Risk Factors for the Development of Post-Infectious Bronchiolitis Obliterans in Children: A Systematic Review and Meta-Analysis

Post-infectious bronchiolitis obliterans (PIBO), one of the major complications of respiratory tract infection, is commonly underdiagnosed. To identify the risk groups that may develop PIBO and avoid misdiagnoses, we investigated the risk factors associated with the development of PIBO. We searched PubMed, Embase, and MEDLINE databases for studies that included risk factors for the development of PIBO published from inception to 13 June 2022. We limited our search to studies that reported the estimates of odds ratio (OR), hazard ratio (HR), or relative risks for developing PIBO. A fixed-effect and a random-effect model were used. We included seven studies reporting data on the risk factors for PIBO in 344 children with PIBO and 1310 control children. Twenty-two variables, including sex, age, respiratory pathogens, symptoms, laboratory and radiologic findings, and mechanical ventilation, were mentioned in at least one study. The significant risk factors mentioned in two or more studies included elevated lactate dehydrogenase levels, pleural effusion, hypoxemia, sex, and mechanical ventilation. The significance of the duration of hospitalization and fever as risk factors for PIBO differed when the studies were classified according to the statistical method. In addition, the risk factors differed according to respiratory infection pathogens. This meta-analysis identified potential risk factors associated with the development of PIBO. The results of this study highlight the importance of avoiding misdiagnosis and help establish management strategies for patients at a high risk of developing PIBO.

Risk Factors for Post-infectious Bronchiolitis Obliterans in Children: A Systematic Review and Meta-Analysis

BACKGROUND

Post-infectious bronchiolitis obliterans (PIBO) is a long-term sequela after an initial insult to the lower respiratory tract. A comprehensive understanding of the factors that contribute to a high risk of developing PIBO is important to help define therapeutic strategies and improve prognosis.

METHODS

We performed a systematic review of published literature available in the online databases including PubMed, Embase, Web of Science, CNKI, Wan Fang, and VIP, with the last search updated on 27 January 2022. Observational studies and case-control studies that provide sufficient data to examine associations between potential risk factors and PIBO were included. Pooled odds ratio (OR) or mean difference (MD) with 95% confidence interval (CI) and heterogeneity were calculated.

RESULTS

A total of 14 risk factors were selected from 9 studies included in the analysis. The strongest risk factors were hypoxemia, mechanical ventilation, tachypnea, and wheezing. Hypoxemia conferred the greatest risk with pooled OR of 21.54 (95% CI: 10-46.36, p < 0.001). Mechanical ventilation ranked second (pooled OR 14.61, 95% CI: 7.53-28.35, p < 0.001). Use of γ-globulin, use of glucocorticoids, co-infection of bacteria, a history of wheezing, and being male were other prominent risk factors. The effects of premature birth, allergic rhinitis, and imaging finding (pulmonary consolidation, atelectasis, pleural effusion) are less clear and require further confirmation. Cases that developing PIBO had a lower age compared with controls (MD, -8.76 months, 95% CI: -16.50 to -1.02, p = 0.03). No significant differences were observed in the duration of fever (MD, 1.74 days, 95% CI: -0.07 to 3.54, p = 0.06). Children diagnosed with PIBO had higher LDH levels (MD, 264.69 U/L, 95% CI: 67.43 to 461.74, p = 0.008) and duration of hospitalization (MD, 4.50 days, 95% CI: 2.63 to 6.37, p < 0.001).

CONCLUSION

In this study, we found that the strongest risk factors for PIBO were hypoxemia, mechanical ventilation, tachypnea, and wheezing. Use of glucocorticoids, γ-globulin, co-infection of bacteria, a history of wheezing, and being male may also play a role. The factors discussed above can inform the generation of a clinical prediction model for the developing PIBO in 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.