An investigation is underway to determine how a rare brain-eating amoeba found its way into a plumbing system of a home in Louisiana, according to the Center for Disease Control.
A four-year-old boy from Mississippi became the fourth confirmed infection in 2013 of the amoeba, Naegleria fowleri, last week, after playing in water from the home in St. Barnard Parish, La.
The Department of Health and Hospitals in Louisiana has confirmed that the amoeba was found in the home's plumbing system.
In previous cases, the CDC has linked the infections to warm water and drought conditions.
"When we go back and look at where exposure may have occurred, we see the infections occur where water levels are low or where there are drought conditions or after a heat wave," Dr. Jennifer Cope, medical epidemiologist at the CDC, told AccuWeather.com.
Naegleri fowleri is thermophillic, or heat-loving, and can thrive in temperatures higher than 100 degrees F.
Temperatures in the New Orleans area have been high enough to sustain the amoeba in recent days. Highs have pushed into the 90s for most of August.
The infections seen this year are not unusual, Cope noted.
Most often, cases are reported in southern-tier states, such as Florida and Texas, during the summer months. The two states have accounted for almost 50 percent of cases reported to the CDC since 1962. The infection is not unprecedented in Louisiana, however.
A human becomes infected with the amoeba when contaminated water enters the nose and travels to the brain, resulting in the infection known as primary amebic meningoencephaltis, or PAM.
The infection destroys brain tissue, resulting in brain swelling. In its early stages, it has similar symptoms of bacterial meningitis such as headache, fever, nausea and vomiting. Later symptoms included stiff neck, confusion, loss of balance, seizures and, in most cases, death.
A total of 128 infections have been reported between 1962 and 2012. In the 10 years from 2003 to 2012, 31 infections were reported in the U.S.
Only one person has survived the infection this summer, 12-year-old Kali Hardig from Arkansas. She was treated with an experimental German drug earlier this summer and was released from Arkansas Children's Hospital Wednesday.
"This is always a very difficult and tragic situation for the families of these people that are impacted and infected," Waterborne Disease and Outbreak Surveillance Coordinator for the CDC Jonathan Yoder said.
"We are certainly optimistic that we're making some progress on understanding the ecology of the organism, understanding what's important for treatment, but certainly there's a lot to learn still."