PUNTA GORDA, Fla. (AP) — A person in southwest Florida has died after being infected with an extremely rare brain-eating amoeba, health officials said.

The Florida Department of Health in Charlotte County confirmed the death Thursday. The agency had previously issued an alert last month, warning residents about the Naegleria fowleri infection.

“I can confirm the infection unfortunately resulted in a death, and any additional information on this case is confidential to protect patient privacy,” Florida Department of Health spokesman Jae Williams said in an email.

Health officials said last month that the infection might have been caused by sinus rinse practices using tap water, but an investigation is ongoing. Sinus solutions should be made using only distilled or sterile water. Tap water should be boiled for at least one minute and cooled before sinus rinsing.

“Infection with Naegleria fowleri is rare and can only happen when water contaminated with amoebae enters the body through the nose,” Williams said. “You cannot be infected by drinking tap water.”

Naegleria fowleri is a single-celled organism that lives in soil and warm fresh water, such as lakes, rivers and hot springs, according to the U.S. Centers for Disease Control and Prevention. It can cause a brain infection when water containing the amoeba goes up the nose. Only about three people in the United States get infected each year, but these infections are usually fatal.