Genetic characteristics of human adenovirus 4a causing an epidemic of febrile illness

ObjectiveTo understand the genetic characteristics of human adenovirus 4a causing an epidemic of febrile illness occurred in a primary school in Tongzhou district of Beijing in October, 2019.

MethodsThe oropharyngeal swabs were collected from the febrile illness cases for the detections of 32 kinds of respiratory viruses and bacteria by real-time PCR. The Fiber, Hexon and Penton gene fragments were amplified and sequenced by PCR for adenovirus positive specimens. The Fiber, Hexon and Penton gene sequences were analyzed by BLAST in NCBI. A phylogenetic tree was constructed by using Fiber, Hexon and Penton gene sequences with software BioEidt 7.2.5 and MEGA 6.06.

ResultsThe oropharyngeal swabs of 6 febrile illness cases were all positive for adenovirus in real-time PCR. There were no other respiratory pathogens detected in the oropharyngeal swabs. Fiber, Hexon and Penton gene sequence alignment results indicated that the adenovirus strains from the 6 cases belonged to adenovirus 4a. The phylogenic tree analysis indicated that the adenoviruses isolated in this epidemic shared high homology with adenovirus 4a circulating in USA in recent years.

ConclusionThis epidemic of febrile illness was caused by human adenovirus 4a.