Molecular Epidemiology and clinical Features Analysis of Respiratory Human Adenovirus Infections in Hospitalized Children: A Retrospective Study in Zhejiang

Abstract Background: HAdV is one of the common pathogens in hospitalized children with respiratory infection (RI). we aim to describe the epidemiological characteristics, clinical features, and genotype of inpatients with HAdV positive with RI.Methods: Respiratory samples were gathered from inpatients diagnosed RI in Children’s Hospital, Zhejiang University School of Medicine and were detected by using Direct Immunofluorescence Assay (DFA) 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 typing of HAdV, and epidemiological characteristic analysis were retrospectively performed. Results: Of 7072 samples collected, 488 cases were identified as HAdV-positive RI. The overall detection rate was 6.9%. The peaked detection rate was 14.1% in January 2019. HAdV-positive cases with RI mainly appeared in winter and summer. 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%,128/48), 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, the most of them were congenital heart diseases (20.5%,17/78). The proportions of hyperpyrexia, duration of fever more than 10 days, severe pneumonia, and proportion of wheezing in the co-infection group were remarkably higher than those in HAdV single-infection group (p<0.05). 4 HAdV species were successfully identified in 155 cases and represented 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 group was significantly higher than the non-severe infected group. Conclusion: HAdV detection rate is related to age and season. Bronchopneumonia accounts for about 70% HAdV -positive inpatients. The common manifestations include hyperpyrexia, cough, wheezing, and shortness of breath. HAdV-B3 and HAdV-B7 are the most common types in children diagnosed with RI.