Genotyping and Clinical Manifestations of Adenoviral Keratoconjunctivitis in Korea

Purpose: This study aimed to identify the predominant adenoviral genotypes responsible for epidemic keratoconjunctivitis (EKC) in Korea and to evaluate genotype distribution and associated clinical manifestations based on molecular confirmation. Methods: Sixty-seven conjunctival swabs were obtained from patients clinically suspected of epidemic keratoconjunctivitis between October 2016 and December 2019. Viral nucleic acids were extracted using the QIAamp® Viral Mini kit and processed via the QIAcube platform. Adenoviral genotypes were molecularly confirmed using polymerase chain reaction (PCR) and sequencing of the hexon gene. Results: Of the 67 specimens, 45 (67.2%) showed positive genotyping results. Adenovirus types D8 (42.2%) and D37 (31.1%) were the predominant genotypes identified. From 2016 to 2018, D8 was the dominant genotype, whereas in 2019, additional genotypes, including B3, D53, D64, and E4, were newly detected during the study period. All patients with confirmed genotypes exhibited conjunctival hyperemia and follicular reaction. Pseudomembrane formation was observed in 68.4% of D8 cases and 57.1% of D37 cases. Corneal involvement, including epithelial defects and subepithelial infiltration, was frequently observed in genotypes D8, D37, D53, and D64, whereas genotypes B3 and E4 showed no corneal involvement, indicating potential trends toward genotype-associated clinical features. Conclusions: Adenoviral genotypes D8 and D37 were the predominant causes of epidemic keratoconjunctivitis in Korea. In 2019, additional genotypes, including B3, D53, D64, and E4, were newly detected, suggesting temporal changes in genotype distribution during the study period. Corneal involvement was more frequently observed in D8, D37, D53, and D64, whereas B3 and E4 showed no corneal involvement. These findings provide descriptive epidemiologic data on adenoviral genotypes in Korea and may serve as baseline information for future studies of genotype-associated clinical manifestations.