Pathogenic Identification And Genetic Characteristics Of Epidemic Keratitis Of Dalian Breakout In2012

Objective:To confirm the pathogen of the outbreak of epidemic keratoconjunctivitis in2012in Dalian, and identify its type;Analysis the major structural and reorganization char-acteristic of human adenovirus type56that is the pathogen of the outbreaks, This willprovide theoretical data for the prevention and treatment of novel recombinant of hu-man adenovirus subgenus D in the future.Method:1. Pathogen identified:30conjunctival samples were collected from the typical casesof the outbreaks of epidemic keratoconjunctivitis in DaLian in2012, Using the fl-uorescence PCR method to confirm the pathogen with human adenoviruses and enteroviruses universal primers, and their specific fragment were sequenced to iden-tify the type.2. Analysis of genetic characteristics: The specimens with human adenovirus-positive detected results were used for virus isolation, and sequenced their majorstructural gene of hexon, penton and spike of full-length gene, Analysed the rec-ombination and system evolution by comparing with the standard strains of hum-an adenovirus.Results:1. There are21positive specimens of fluorescent PCR test for adenovirus,Thepositive rate was70.0%(21/30).The L1fragment sequences of Hexon gene showed highly homology with that of HAdv-19, HAdv-26and HAdv-56.On the phylogenetic tree constructed after the multiple sequence alignment withHAdV-D56and the recombinant are in the same branch.2. The full-length sequence phylogenetic analysis results according to the Hexon,Penton and Fiber gene showed that the strain is human adenovirus type56,Theconsistency between Hexon and Fiber gene sequences and HAdV-D56standardstrain is100%. There are15gene mutation in the Penton gene sequence, of which14were synonymous mutation,1nucleotide mutations cause amino acid changes.There are1gene mutation in the Fiber gene sequence, to changed the amino acidsequence. Analysis showed that the recombinant of virus Penton gene may be inv-olved in the restructuring of HAdV-D39.Conclusions:Caused the epidemic keratoconjunctivitis epidemic is human adenovirus type56.There is no official report on this virus, or other worldwide keratoconjunctivitisepidemic reports caused by the virus. We need to further studies about whetheramino acid changes of Penton and Fiber fragment can cause strain invasive en-hanced and lead to such a outbreak or not.