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

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

Retrospective case series.

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.

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.

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.