The Naegleria fowleri amoeba is responsible for the death of a 4-year-old in Louisiana. (UIG Getty Images)

A deadly brain-eating amoeba found in the water supply of a New Orleans suburb could be related to the after-effects of Hurricane Katrina, according to officials from the Louisiana Department of Health and Hospitals.

The Louisiana Department of Health and Hospitals and the U.S. Centers for Disease Control (CDC) confirmed last week that the deadly Naegleria fowleri amoeba has been found in the St. Bernard Parish water supply.

The pathogens were discovered after a 4-year-old boy was infected with the amoeba and died. The Naegleria fowleri thrives in warm freshwater and causes a deadly form of meningitis when inhaled through the nose.

Jake Causey, the chief engineer at the Louisiana Department of Health and Hospitals, said the severe drop in population in St. Bernard's parish immediately after Hurricane Katrina could have affected the water supply. If a majority of a town's population leaves the area, the water in the water system may remain sitting in pipes longer. As a result the chlorine can dissipate and pathogens can grow.

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"One of the questions was how the amoebas could have entered the system," Causey told ABCNews.com. "There's quite a few ways. We just didn't think we should ignore the fact the whole system had about 15 feet of water on it."

Before Hurricane Katrina the parish's population was approximately 67,000, according to the St. Bernard Chamber of Commerce. After the storm, the population dipped below 15,000, according to the U.S. Census Bureau.

Jonathan Yoder, an epidemiologist with the Division of Foodborne, Waterborne, and Environmental Disease at the CDC, said anything that could dilute the chlorine used to disinfect the water supply could lead to more pathogens in the system.

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"This organism likes warm water and if it can get in the system and there's not enough disinfection, it can colonize and it can grow in the system," said Yoder.

While under-use of the water system due to a population drop could affect the chlorine levels, Yoder said, but he clarified it was too early in the CDC's investigation to confirm, and it was only speculation at this point that Hurricane Katrina could have affected the water supply.

The parish is currently flushing out the water system with chlorine, and water has been turned off at schools in the area.

This is the first time that the amoebas have been found in the treated water of a U.S. water system.

Early symptoms of a Naegleria infection include a severe frontal headache, fever, nausea and vomiting, according to the CDC. But those can swiftly give way to a stiff neck, seizures, confusion and hallucinations as the amoeba makes its way up through the nasal cavity into the brain.

"After the start of symptoms, the disease progresses rapidly and usually causes death within about five days," the according to the CDC. "People should seek medical care immediately whenever they develop a sudden onset of fever, headache, stiff neck and vomiting, particularly if they have been in warm freshwater recently."