Characteristics of the human adenovirus infections from influenza-like illness samples in Xi′an / 中华实验和临床病毒学杂志

ABSTRACT

Objective@#To analyze the epidemiological characteristics and the molecular types of human adenovirus (HAdV) from influenza-like illness (ILI) samples with negative influenza virus in Xi'an from January 2013 to December 2015.@*Methods@#Samples from patients with ILI were collected from two national influenza sentinel surveillance hospitals during 2013—2015 in Xi′an. HAdV was detected by real-time PCR, and then the positive samples were inoculated into Hep-2 cells to isolate the viruses. The amplified products were purified and sequenced of hexon gene, and the sequences were compared with the Genebank data and phylogenetic trees were constructed.@*Results@#In 2367 samples, 88 samples were positive for HAdV, the positive rate was 3.72%. There were 7 subtypes detected, and the rates of each subtype are as follows: HAdV-1 was 9.09%, HAdV-2 was 22.73%, HAdV-3 was 23.86%, HAdV-4 was 5.68%, HAdV-5 was 7.95%, HAdV-6 was 3.41% and HAdV-7 was 1.14%. Males had higher infection rate than females, but there was no significant difference. The patients were divided into 6 groups according to age. There were 3 positive samples among those under 1 year of age, 36 positive samples among those 1 to 3 years old, 26 positive samples among those 4 to 6 years old, 16 positive samples in those 7 to 18 years old, 5 positive samples in 19 to 59 years old and 2 positive samples in those older than sixty years of age. HAdV infection was primarily confined to children under 7 years of age.@*Conclusions@#HAdV-3 and HAdV-2 were the dominant epidemic strains during 2013—2015 in Xi′an. Children younger than 7 years were the main susceptible population. HAdV infections circulate all year-round and there was no considerable seasonal variation.