title: Human adenovirus type 8: the major agent of epidemic keratoconjunctivitis (EKC).
abstract: Human adenovirus type 8 (HAdV-8) is the most common causative agent of a highly contagious eye disease known as epidemic keratoconjunctivitis (EKC). HAdV-8 strains have been classified into genome types HAdV-8A to 8K and HAdV/D1 to D12 according to restriction endonuclease analysis. This review focuses on the significance of HAdV-8 as an agent of EKC. Molecular analysis of HAdV-8 genome types HAdV-53 and HAdV-54 was performed to reveal potential genetic variation in the hexon and fiber, which might affect the antigenicity and tropism of the virus, respectively. On the basis of the published data, three patterns of HAdV-8 genome type distribution were observed worldwide: (1) genome types restricted to a microenvironment, (2) genome types distributed within a country, and (3) globally dispersed genome types. Simplot and zPicture showed that the HAdV-8 genome types were nearly identical to each other. HAdV-54 is very close to the HAdV-8P, B and E genomes, except in the hexon. In a restriction map, HAdV-8P, B, and E share a very high percentage of restriction sites with each other. Hypervariable regions (HVRs) of the hexon were conserved and were 100% identical among the genome types. The fiber knob of HAdV-8P, A, E, J and HAdV-53 were 100% identical. In phylogeny, HVRs of the hexon and fiber knob of the HAdV-8 genome types segregated into monophyletic clusters. Neutralizing antibodies against one genome type will provide protection against other genome types, and the selection of future vaccine strains would be simple due to the stable HVRs. Molecular analysis of whole genomes, particularly of the capsid proteins of the remaining genome types, would be useful to substantiate our observations.
authors.affiliation: Unit of Microbiology, Faculty of Medicine, AIMST University, 08100 Bedong, Semeling, Kedah Darul Aman, Malaysia. Electronic address: arun_adhikary@msn.com.
authors.forename: Arun Kumar
authors.initials: AK
authors.lastname: Adhikary
authors.affiliation: Unit of Pathology, Faculty of Medicine, AIMST University, 08100 Bedong, Semeling, Kedah Darul Aman, Malaysia.
authors.forename: Urmila
authors.initials: U
authors.lastname: Banik
mesh_terms: D000257:Adenoviridae Infections / Q000453:epidemiology* / Q000821:virology*; D000260:Adenoviruses, Human / Q000145:classification / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification*; D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology; D000914:Antibodies, Viral / Q000276:immunology; D036022:Capsid Proteins / Q000235:genetics; D005838:Genotype; D006801:Humans; D007639:Keratoconjunctivitis, Infectious / Q000453:epidemiology* / Q000821:virology*; D058974:Phylogeography
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D036022:Capsid Proteins; C018315:hexon capsid protein, Adenovirus
keywords: Adenovirus type 8; EKC; Genome type; Molecular analysis