Louisiana Officials Warn of Sight-Loss Amoeba in Tap Water

Louisiana health officials have issued an urgent warning to residents after a microscopic organism, Acanthamoeba, commonly found in tap water, has been linked to five cases of permanent blindness and one death. Since 2024, ten cases of Acanthamoeba-related illness have been identified across the state.

Acanthamoeba is a ubiquitous microorganism found in soil, dust, and water, including household tap water. While most individuals encounter the amoeba without developing illness, infections can lead to severe health consequences. The Centers for Disease Control and Prevention notes that the amoeba can enter the body through open wounds, inhalation, or the eyes, particularly when contact lenses are exposed to contaminated water.

The severity of the infection depends on where the amoeba establishes itself, with potential outcomes ranging from painful eye conditions to fatal brain disease. Acanthamoeba keratitis, an infection affecting the cornea, is one of the most common conditions. It can affect individuals with no prior health issues and lead to permanent vision loss.

Of the ten cases reported in Louisiana over the past two years, eight involved Acanthamoeba keratitis. Seven of these patients wore contact lenses, and five were left permanently blind. Two other patients developed severe forms of the disease affecting the sinuses and the brain, with the latter resulting in a fatality. Both of these patients had weakened immune systems and reported using tap water for nasal irrigation.

State health officials emphasized that while the use of tap water in these instances does not definitively establish it as the source, it highlights the importance of safe water practices. They advise using appropriate water for nasal rinsing, maintaining proper contact lens hygiene, and taking precautions with medical devices to reduce risk. Drinking tap water is not considered a risk for Acanthamoeba infection.

From Blurry Vision to Deadly Disease

The Cleveland Clinic estimates that approximately 1,500 cases of Acanthamoeba keratitis are diagnosed annually in the U.S. Symptoms include eye pain, redness, blurred vision, light sensitivity, excessive tearing, and a sensation of a foreign object in the eye. Treatment typically involves prescription antiseptic eye drops, but about 40% of cases may require surgery if they do not respond adequately to medication. Early treatment, ideally within three weeks of symptom onset and before the infection spreads beyond the second layer of the cornea, improves the chances of a positive outcome.

Cases of Acanthamoeba affecting other parts of the body are rarer but can be more dangerous. The CDC reported 208 such cases nationwide between 1955 and 2025. Individuals with compromised immune systems are particularly susceptible to these more severe infections, which can impact the skin, sinuses, and brain. Symptoms can be difficult to recognize and may be initially misdiagnosed. Health officials urge those with weakened immune systems experiencing seizures, confusion, headaches, fever, sinus problems, vision changes, or unusual skin symptoms to seek immediate medical attention.

While skin and sinus infections can often be treated if detected early, the amoeba's spread to other body parts makes treatment more challenging. Granulomatous amebic encephalitis, a rare and typically fatal condition where the amoeba infects the brain, represents the most severe complication.