Left: Kali Hardig, 12, who survived a rare and often fatal infection caused by a brain-eating amoeba, speaks to reporters at Arkansas Children's Hospital in Little Rock, Ark. Right: An image of naegleria foweleri, enlarged under a microscope. Left: Danny Johnston/AP;Right: U.S. Centers for Disease Control and Prevention

Scientists have found a brain-eating amoeba in the water supply of a Louisiana parish where a child died last month from a brain infection caused by the microscopic organism, according to state health officials.

Test results from the U.S. Centers for Disease Control and Prevention confirmed the Naegleria fowleri amoeba was found in four locations of the St. Bernard Parish water system.

State health officials say the water is safe to drink but that people should take caution to not let it enter their nose.

The brain-eating amoeba called Naegleria fowleri is often found in warm bodies of freshwater, such as lakes, rivers and hot springs. The amoeba typically enters the body through the nose as people are swimming or diving. It can then travel to the brain, causing primary amebic meningoencephalitis, or PAM.

Initial symptoms usually start within one to seven days and may include a headache, fever, nausea and vomiting. The disease progresses rapidly, and other symptoms can include a stiff neck, confusion, loss of balance, seizures and hallucinations. The infection destroys brain tissue, which can ultimately lead to brain swelling and death.

There were 128 infections reported in the United States between 1962 and 2012, according to the Centers for Disease Control and Prevention.

In an unrelated incident, the second-ever known survivor of the amoeba was released from the hospital this week in Arkansas.

Twelve-year-old Kali Hardig went home Wednesday after being hospitalized since July.

She's believed to have contracted the same type amoeba found in Lousiana after visiting a now-shuttered water park that features a sandy-bottomed lake.

Doctors say Kali's success is due in large part to experimental treatment that included the use of a breast cancer medication.

She went from being hooked up to a ventilator to breathing on her own and relearning to speak, walk and eat.

Al Jazeera and wire services