Detection of human bocavirus in children with acute respiratory tract infections in Lanzhou and Nanjing, China

The Burden of Human Bocavirus 1 in Hospitalized Children With Respiratory Tract Infections

BACKGROUND

Human bocavirus 1 (HBoV1) is frequently codetected with other viruses, and detected in asymptomatic children. Thus, the burden of HBoV1 respiratory tract infections (RTI) has been unknown. Using HBoV1-mRNA to indicate true HBoV1 RTI, we assessed the burden of HBoV1 in hospitalized children and the impact of viral codetections, compared with respiratory syncytial virus (RSV).

METHODS

Over 11 years, we enrolled 4879 children <16 years old admitted with RTI. Nasopharyngeal aspirates were analyzed with polymerase chain reaction for HBoV1-DNA, HBoV1-mRNA, and 19 other pathogens.

RESULTS

HBoV1-mRNA was detected in 2.7% (130/4850) samples, modestly peaking in autumn and winter. Forty-three percent with HBoV1 mRNA were 12-17 months old, and only 5% were <6 months old. A total of 73.8% had viral codetections. It was more likely to detect HBoV1-mRNA if HBoV1-DNA was detected alone (odds ratio [OR]: 3.9, 95% confidence interval [CI]: 1.7-8.9) or with 1 viral codetection (OR: 1.9, 95% CI: 1.1-3.3), compared to ≥2 codetections. Codetection of severe viruses like RSV had lower odds for HBoV1-mRNA (OR: 0.34, 95% CI: 0.19-0.61). The yearly lower RTI hospitalization rate per 1000 children <5 years was 0.7 for HBoV1-mRNA and 8.7 for RSV.

CONCLUSIONS

True HBoV1 RTI is most likely when HBoV1-DNA is detected alone, or with 1 codetected virus. Hospitalization due to HBoV1 LRTI is 10-12 times less common than RSV.

Comparison of the clinical features of human bocavirus and metapneumovirus lower respiratory tract infections in hospitalized children in Suzhou, China

OBJECTIVE

We compared the clinical data of hospitalized children with lower respiratory tract infections caused by human bocavirus (HBoV) and human metapneumovirus (hMPV).

METHODS

In total, 8,430 children admitted to the Department of Respiration, Children's Hospital of Soochow University for lower respiratory tract infections from January 2017 to October 2021 were enrolled. Seven common respiratory viruses, including respiratory syncytial virus, influenza virus A, influenza virus B, parainfluenza virus (PIV) I, PIV II, PIV III, and adenovirus, were detected by direct immunofluorescence assay, whereas human rhinovirus and hMPV were detected by reverse transcription-polymerase chain reaction. Mycoplasma pneumoniae (MP) and HBoV were detected by real-time fluorescence quantitative polymerase chain reaction. Bacteria was detected in blood, nasopharyngeal secretion, bronchoalveolar lavage specimen or pleural fluid by culture. In parallel, MP was detected by enzyme-linked immunosorbent assay. In addition, we performed metagenomic testing of alveolar lavage fluid from some of the patients in our study.

RESULTS

The detection rate of HBoV was 6.62% (558/8430), whereas that of hMPV was 2.24% (189/ 8430). The detection rate of HBoV was significantly higher in children aged 1 to <3 years than in other age groups, but there were no significant differences in positivity rates for hMPV by age. Before 2020, the incidence of HBoV infection peaked in summer and autumn, whereas that of hMPV peaked in spring. The epidemiology of both HBoV and hMPV has changed because of the impact of the novel coronavirus. Among the positive cases, the HBoV mixed infection rate was 51.6%, which was similar to that for hMPV mixed infection (44.4%). Comparing clinical characteristics between HBoV and hMPV single infection, the median age of children was 17 months in the HBoV group and 11 months in the hMPV group. In the HBoV single infection group, 31 patients (11.5%) had pulse oxygen saturation of less than 92% on admission, 47 (17.4%) had shortness of breath, and 26 (9.6%) presented with dyspnea. Meanwhile, four patients (3.8%) in the hMPV single infection group had pulse oxygen saturation of less than 92% on admission, eight (7.6%) displayed shortness of breath, and three (2.9%) had dyspnea. The proportion of patients requiring mechanical ventilation and the rate of PICU admission were higher in the HBoV group than in the hMPV group.

CONCLUSION

The prevalence of HBoV infection is higher than that of hMPV infection in children with lower respiratory tract infection in Suzhou, and HBoV is more likely to cause severe infection than hMPV. Public health interventions for COVID-19 outbreaks have affected the prevalence of HBoV and hMPV.

Comparison of clinically related factors and treatment approaches in patients with acute bronchiolitis

AIM

Acute bronchiolitis is a lower respiratory tract infection caused by viral agents in children aged under two years. Treatment includes hydration, oxygen, nebulized salbutamol, and intravenous steroids. This study aimed to determine the clinically related factors, the effect of viral agents on the clinical picture, and the efficacy of treatment methods in patients admitted with acute bronchiolitis.

MATERIAL AND METHODS

Patients aged under two years of age who were hospitalized with a diagnosis of moderate/severe acute bronchiolitis between March 2015 and March 2019 were included in the study. Demographic data, hospitalization time, body temperature, presence of congenital heart disease, history of atopy, acute-phase reactants, mean platelet volume values, and respiratory virus panel results were recorded. The treatment modalities, length of hospitalization, intensive care hospitalization, and high-flow nasal cannula oxygen therapy (HFNC) were recorded.

RESULTS

Four hundred twenty-two patients were included in the study. The duration of hospitalization was found to be significantly longer in patients aged under one year and in patients with acyanotic congenital heart disease. A single viral agent was detected in 69 (51.9%) patients. Rhinovirus was detected in 70 patients and RSV was detected in 37. The duration of hospitalization was found to be significantly shorter in patients who received only oxygen and/or intravenous fluid treatment compared with those who received nebulized salbutamol and/or intravenous steroids. In addition, and there was no significant difference between the groups in terms of HFNC and hospitalization in the intensive care unit.

CONCLUSION

Rhinovirus was the most common cause of acute bronchiolitis in our study. It was observed that congenital heart disease prolonged the length of hospitalization. In the treatment approaches, it was observed that hydration and oxygen therapy were sufficient treatment methods for the patients, in accordance with the recommendations of the American Academy of Pediatrics, and giving nebulized therapy prolonged the hospitalization period due to the treatment discontinuation steps.