Swimmer in Sea of Galilee Infected with Sight-Threatening Parasite

A 20-year-old man has been hospitalized with a Microsporidium infection in his eye after swimming in the Sea of Galilee during the summer vacation. The infection, which can potentially cause permanent vision damage, was diagnosed after the young man experienced pain and blurred vision for weeks. His mother reported that he underwent intensive treatment, including the removal of corneal epithelial layers twice and frequent eye drops, even at night. The full extent of the damage to his eye remains unclear.

The man visited Ein Gev on July 24 and swam at Kursi Beach on July 31. About two weeks after his last visit, symptoms began to appear. By August 17, he was admitted to a hospital's eye emergency room, where doctors suspected Microsporidium based on a clinical examination. A PCR test later confirmed the diagnosis.

Microsporidium is a single-celled parasite found in water sources and sometimes mud. It can survive for extended periods in nature as spores before infecting a host. While not rare, the parasite is difficult to diagnose. In Israel, approximately 0.4% of eye keratitis cases are attributed to it, with about 40 cases reported in 2022, all linked to the Sea of Galilee. Three swimmers were infected in August 2023.

Infection occurs through direct contact of the eye with contaminated water. Symptoms typically include redness, a foreign body sensation, tearing, and sometimes decreased visual acuity, usually affecting one eye initially. While most cases resolve on their own, in rare instances, the infection can penetrate deeper into the cornea, leading to irreversible vision loss.

Medical attention is advised for anyone experiencing these symptoms after exposure to Sea of Galilee water. Antibiotic eye drops may be prescribed if infection is suspected. The recommendation to swim with goggles in the Sea of Galilee is likely to remain in effect as long as infection reports persist, especially during peak summer season. Unlike natural water bodies, swimming pools are generally safe as they undergo chlorination.