Serotype determination of adenoviruses in children with respiratory infection

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 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.

Identification of adenovirus species in Iranian pediatric population with severe acute respiratory infections

Aim: In this study we aimed to find the rate of human adenovirus (HAdV) infections and identify HAdVs molecular epidemiology in children younger than 5 years old with clinical diagnosis of severe acute respiratory infections in Iran. Patients & methods: A semi-nested PCR with in-house designed primers for HAdV was performed on 200 oropharyngeal swabs collected within 5 days from the onset of symptoms. The positive samples were subjected to sequencing and a phylogenetic tree was drawn. Results: Out of 200 specimens, 71 (35.5%) cases were positive for HAdVs. Detected strains matched with HAdV species B (80.3%), C (15.5%), D (2.8%) and E (1.8%). HAdV- B14/55 and HAdV-B3 were the most prevalent types, respectively. Conclusion: This study showed that infections with HAdV species B, were common in children, who were clinically diagnosed as severe acute respiratory infection cases in Iran. The results could be useful for future epidemiological researches.