Louisiana health officials are warning residents not to use tap water for nasal rinsing or contact lens care after identifying 10 Acanthamoeba infections across the state since 2024, five of which left patients with permanent vision loss and one of which killed a patient this year. The microscopic organism, found worldwide in water, soil and dust, can cause eye problems or potentially fatal brain disease, and officials say two of the most severe cases this year involved patients with weakened immune systems who had used tap water in nasal irrigation devices.
Of the 10 cases reported since 2024, eight were Acanthamoeba keratitis infections affecting the cornea, and seven of those eight patients were contact lens wearers, according to ABC News. Five of those keratitis cases resulted in permanent vision loss. The remaining two infections occurred in 2026 and were far more serious, with one affecting the sinuses and the other spreading to the brain. The brain infection proved fatal, the outlet reported.
State epidemiologist Theresa Sokol said Acanthamoeba infections are rare but can have devastating consequences, a warning that landed heavily this week given the outcomes among Louisiana’s most recent patients. Both of the 2026 patients with serious disease reported using tap water in nasal irrigation systems, according to the Louisiana Illuminator. Both also had compromised immune systems, a factor officials say makes people particularly vulnerable to severe disease.
Officials Stop Short of Blaming the Water Supply
Despite the warning, state health officials have been careful about what they are and are not claiming. Tap water has not been established as the source of the Acanthamoeba infections, the Illuminator reported, and officials said drinking tap water does not put a person at risk for contracting the organism. The caution applies specifically to nasal rinsing and to cleaning or storing contact lenses, not to ordinary drinking or cooking use.
That distinction matters because Acanthamoeba enters the body through several different routes — cuts or wounds, inhalation into the nose or lungs, or direct contact with the eyes — and the risk profile changes depending on how water is used. Health officials urged safe water practices and proper contact lens hygiene as the primary safeguards, rather than avoiding tap water altogether.
How Serious Infections Can Become
When Acanthamoeba reaches the cornea, it causes a condition called Acanthamoeba keratitis, which can be treated with prescription antiseptic eye drops such as chlorhexidine and polihexanide. But the outlook is not straightforward: about 40% of keratitis cases do not respond adequately to drops alone and may require surgery, and outcomes tend to be better when treatment begins before the disease spreads beyond the cornea’s second layer, generally within three weeks of initial symptoms.
Far rarer, and far more dangerous, is granulomatous amebic encephalitis, a condition in which Acanthamoeba attacks the brain. The condition is almost always fatal, which aligns with the outcome of the Louisiana brain infection reported this year. Severe Acanthamoeba disease can also affect the skin and sinuses in addition to the brain, and officials urged immunocompromised people experiencing seizures, confusion, headaches, weakness, fever, sinus problems, vision changes or unusual skin symptoms to seek medical attention immediately.
How Rare These Infections Really Are
National data underscore just how unusual non-keratitis Acanthamoeba infections are. The CDC recorded 208 such cases across the country between 1955 and 2025, with the annual count typically ranging from zero to 12 cases nationwide. A study cited by the network estimated that these non-keratitis infections affect only three to 12 people annually in the U.S., but carry an 82% fatality rate when they occur.
Acanthamoeba keratitis, by contrast, is far more common. The Cleveland Clinic estimates roughly 1,500 cases are diagnosed in the United States each year, the vast majority tied to contact lens use, which is consistent with the pattern seen in Louisiana’s own case count. The gap between that figure and the rarity of brain or sinus infections helps explain why officials are drawing a sharp line between eye-related risk from contact lens hygiene and the separate, much rarer danger tied to nasal rinsing.
