Officials believe the child is a 4-year-old boy from Mississippi who may have come in contact with the waterborne Naegleria fowleri amoeba while playing on a toy water slide,
St. Bernard Parish President David Peralta told CNN affiliate WWLTV, water samples taken from the home tested positive for the amoeba, after being tested at the Louisiana Department of Health and Hospitals.
The state health department has not released the child's age or identity.
On Thursday, out of "an abundance of caution," St. Bernard Parish began treating its water system with additional chlorine and flushing any potentially contaminated water from its lines.
The Mississippi boy's death is the second widely reported loss of a child due to this infection in less than two weeks.
Naegleria fowleri is found in hot springs and warm freshwater and enters the body through the nose and travels to the brain and is 98% fatal.
The first symptoms of primary amoebic meningoencephalitis appear one to seven days after infection, including headache, fever, nausea, vomiting and a stiff neck, according to the CDC.
"Later symptoms include confusion, lack of attention to people and surroundings, loss of balance, seizures and hallucinations," the agency website says. "After the start of symptoms, the disease progresses rapidly and usually causes death within one to 12 days."
Here are some tips from the CDC to help lower your risk of infection:
Avoid swimming in freshwater when the water temperature is high and the water level is low.
Hold your nose shut or use nose clips.
Avoid stirring up the sediment while wading in shallow, warm freshwater areas.
If you are irrigating, flushing or rinsing your sinuses (for example, by using a neti pot), use water that has been distilled or sterilized.