Adenoviral Keratoconjunctivitis in Korea: Serotypes and Clinical Characteristics

Purpose: Human adenoviruses are a major cause of epidemic keratoconjunctivitis. Of over 60 genotypes, subgroup D is associated with epidemic keratoconjunctivitis. There are, however, no data regarding the genotypes of conjunctivitis-causing adenoviruses in Korea. The purpose of this study was to determine the types of adenoviruses causing epidemic keratoconjunctivitis and clinical manifestations in Korea.Methods: From November 2016 to September 2017, 20 conjunctival swab specimens were collected from patients who were clinically suspected to have adenoviral keratoconjunctivitis. Nucleic acids were extracted using a QIAamp Viral mini kit and processed on the QIAcube platform. Genotyping targeted for adenovirus capsid hexon genes was performed by using the polymerase chain reaction and sequencing techniques. Patient ages ranged from 18 days to 69 years (median, 37 years).Results: Of 20 collected specimens, 17 (85.0%) were genotyped. Three samples were not amplified with our primer sets. Eleven samples (64.7%) were adenovirus type 8, five (29.4%) were type 37, and one was type 64. All 17 genotyped patients showed conjunctival injections (100%) and follicles (100%), and 12 (84.6%) showed pseudomembrane formation. In case of patients genotyped type 8, most of them showed corneal manifestations and involvement of cornea by type 37 showed filamentary keratitis.Conclusions: This study showed that the polymerase chain reaction and direct sequencing for adenovirus hexon genes of conjunctival swab samples were effective techniques for genotyping the adenoviruses that cause epidemic keratoconjunctivitis. The most common causes of adenoviral keratoconjunctivitis in Korea were adenovirus types 8 and 37 in this period of time. Conjunctival injection, follicle formation, and pseudomembrane formation were the major manifestations of adenovirus types 8 and 37 infections.