Continued circulation and phylogenetic analysis of human adenovirus-55 in China during 2006-2016

Objective To better understand the evolution and epidemiology of human adenovirus-55 (HAdV-55) and provide a scientific basis for the prevention and control of the epidemic of HAdV-55 in China. Methods HAdV-55 isolates from 5 provinces in China included Beijing, Hebei, Shandong, Hunan and Yunnan were collected during 2011-2014. The hexon, fiber and penton base gene were sequenced, and compared with other strains of HAdV-55 sequences downloaded from GenBank for homology and evolution analysis. Results During the past decade, HAdV-55 was found in 15 provinces throughout China. Genetic and phylogenetic analysis showed that the HAdV-55 virus is highly conservative in evolution due to aggregation in a branch in the evolutionary tree. However, bayesian phylogenetic tree shows a certain time evolution trend. The evolution rate of hexon and fiber gene of HAdV-55 are 5.228×10-5 and 1.238×10-4 substitutions/site/year respectively, and the latest coevolutionary ancestor tMRCA of hexon gene can be traced back to 1963. Conclusions HAdV-55 has been widely spread and continued circulating in China. Establishing effective monitoring system and conducting vaccine related research is very important for its control and prevention. Key words: New adenovirus type 55; Acute respiratory infection; Bayesian evolutionary analysis; Gene