Etiological Study of Acute Conjunctivitis Caused by Human Adenovirus in Shanxi Province, China, between 2016 and 2019

Human adenovirus (HAdV) is the primary cause of acute conjunctivitis. To improve our understanding of the etiology of adenoviral conjunctivitis, ocular samples were collected from 160 conjunctivitis cases in the Shanxi province of northern China between 2016 and 2019. Through preliminary identification, virus isolation, and type identification, a total of 63 HAdV isolates were obtained from the samples. Three species and seven types (HAdV-3, HAdV-4, HAdV-8, HAdV-37, HAdV-53, HAdV-64, and HAdV-85) were detected, with HAdV-64, HAdV-3, and HAdV-8 being the predominant types in 2016, 2018, and 2019, respectively. Further phylogenetic analysis indicated the relative genomic stability of seven HAdV-type strains, except for 4 HAdV-3 strains in 2018 with a novel amino acid insertion site (Pro) between P19 and S20 in the penton base gene. It is worth noting that the genomes of two Shanxi HAdV-85 strains from 2016 were almost identical to those of previously reported HAdV-85 strains that circulated in Japan in 2014 to 2018. China was the second country to sample and isolate HAdV-85, suggesting that HAdV-85 might be underreported as an ocular pathogen. Data obtained in this study provide valuable information on the prevalence of acute conjunctivitis caused by HAdV. IMPORTANCE HAdV types in cases of conjunctivitis in Shanxi province, China, in 2016 to 2019 showed evident diversity, with seven types (HAdV-3, HAdV-4, HAdV-8, HAdV-37, HAdV-53, HAdV-64, and HAdV-85) being identified, and relative genome stability of these viruses was observed. In addition, China was the second country to sample and isolate HAdV-85, which suggests that HAdV-85 might be underreported as an important pathogen associated with ocular infections. These results enhance the understanding of the etiology of adenoviral conjunctivitis and may aid in the development of prevention and control strategies for HAdV-related ocular infections in China.