Outbreak of Microsporidial Keratoconjunctivitis Associated With Water Contamination in Swimming Pools in Taiwan.

PURPOSE: To report an outbreak of microsporidial keratoconjunctivitis resulting from a swimming pool in Taiwan.

DESIGN: Retrospective case series.

METHODS: The records of 13 teenagers (15 eyes) contracting microsporidial keratoconjunctivitis after swimming in a local swimming pool were reviewed. Corneal scrapings were collected in all eyes at a tertiary referred hospital in June 2017. Gram stain, modified Kinyoun acid-fast stain, polymerase chain reaction (PCR), and gene analysis of the microsporidian 16S ribosomal RNA (rRNA) were examined in all 15 cases.

RESULTS: Symptoms occurred 1-12 days after the water contact. At presentation, all eyes showed nonpurulent conjunctivitis and small, plaque-like epithelial lesions peripherally (n = 6), centrally (n = 3), both peripherally and centrally (n = 5), or centrally with superficial punctate keratopathy (n = 1). During the follow-up period, 10 eyes developed central superficial punctate keratopathy (n = 6) or subepithelial haze or infiltrates, which were distributed centrally (n = 2) or peripherally (n = 3), following development of plaque-like epithelial lesions. The results of Gram stain and modified Kinyoun's acid-fast stain were confirmatory in 10 cases (67%). All 15 cases yielded positive PCR results and were all identified to be Vittaforma corneae. All followed-up eyes healed without sequelae using topical levofloxacin and betamethasone eye drops.

CONCLUSIONS: Microsporidial keratoconjunctivitis can develop from contact with swimming pool water. The clinical course initially manifested as rapidly resolving conjunctivitis and peripheral plaque-like epithelial lesions, followed by paracentral or central plaque-like epithelial lesions, which evolved into subepithelial haze or infiltrates.