Epidemic keratoconjunctivitis caused by a new genotype of adenovirus type 8 (Ad8)-a chronological review of Ad8 in Southern Taiwan.

PURPOSE To understand the pathogenic evolution of viral keratoconjunctivitis in Kaohsiung, Taiwan, a retrospective molecular and clinical analysis was conducted. METHODS From January 1990 to December 1994, conjunctival swab samples from patients suspected of having viral conjunctivitis were collected for viral culture isolation, neutralization test (NT), and endonuclease cleavage analysis. Six restriction endonucleases, comprising HindIII, BamHI, SalI, SstI, SmaI, and PstI, were used for cleavage. Clinical examinations of patients were performed by two senior ophthalmologists. RESULTS Twenty-one cases of a new genotype of adenovirus (Ad) type 8, designated as Ad8H, were discovered in the 27 detected adenovirus cases. The Ad8H has a distinct cleavage pattern, especially by HindIII and SalI. The Ad8H keratoconjunctivitis induced more subconjunctival hemorrhage (33.3%), keratitis (33.3%), and lymphadenopathy (85.7%) than other genotypes of Ad8 previously isolated in Kaohsiung, Taiwan. CONCLUSION We have discovered a new genotype, Ad8H, which was prevalent as the main pathogen of the adenoviral keratoconjunctivitis in Kaohsiung, Taiwan from 1990 to 1994. Adenovirus type 8 is evolving into more genotypes with a trend towards more severe symptoms, including subconjunctival hemorrhage, keratitis, and lymphadenopathy.