Rare amoeba killed boy in St. Bernard
A day after public health officials confirmed that a Mississippi boy died in August after becoming infected with a rare brain-eating amoeba from contaminated water at a St. Bernard Parish home, local officials sought to ease concerns about the water supply and infectious-disease specialists emphasized that the chance of others contracting the disease is extremely low.
But while officials said that initial tests of the parish’s water did not find any indication of the rare contaminant, a state health department official said the area had low levels of bacteria-killing chlorine in the supply.
On Friday, St. Bernard officials said they were taking precautionary steps after the Louisiana Department of Health and Hospitals concluded that the 4-year-old boy had likely contracted encephalitis from contaminated water on a slip-and-slide.
Tests showed that water on the inflatable toy was contaminated by Naegleria fowleri amoeba, which also turned up in a hose attached to an outdoors faucet and in a toilet tank inside the home.
As a result, Parish President David Peralta said officials were in the process of flushing the parish water supply with chlorine to minimize the threat of bacteria.
Peralta said additional test results were pending, but that initial reviews determined “no evidence of the parasite” in the water.
“We don’t really feel it’s necessary, but as a precaution, let’s do it,” Peralta said. “We’d rather be safe than sorry.”
Since Naegleria fowleri cannot be contracted by drinking water, public health officials say the local water supply remains safe to drink.
The August death marked the third Naegleria fowleri-related death in Louisiana since 2011, the CDC said in a news release Thursday. Most people who contract the disease — 32 total from 2001 to 2010 nationwide — did so after swimming in warm, freshwater bodies of water and ingesting contaminated water through their noses. When infections occur, the water containing the amoeba enters the body through the nose and is pushed into the brain.
Only 128 people have reportedly contracted the disease in the U.S. since 1962, according to the Centers for Disease Control and Prevention. One of those patients survived the nearly always fatal illness, although news reports show that a 12-year-old Arkansas girl who became infected this summer and was hospitalized has been successfully fighting the infection.
State tests show that several areas in the parish — including near where the boy became infected — showed low chlorine levels in the water, Christina Stephens, a DHH spokeswoman, said in an email Friday.
“In some areas, there were only trace amounts. In the area near the home where the Naegleria fowleri was found, there were low levels of chlorine, though the system was not out of compliance,” Stephens said.
The free-living microscopic amoeba is common in warm, stagnant water. Health experts are unsure why so few ultimately become infected, given that many people likely come in contact with the amoeba.
Though public health specialists caution the difficulty in pinpointing the cause of the amoeba, several experts said that low levels of chlorine could potentially play a factor. Water treated with chlorine is unlikely to test positive for the single-celled organisms.
“Certainly, if you have water that’s not used, and it sits in the pipes or sits in tanks for a long period of time, if the chlorine level is low, or there’s no residuals, you have an environment where it could grow,” said LuAnn White, the interim dean of the School of Public Health and Tropical Medicine at Tulane University.
Warm temperatures and low water levels also factor in the quantity of the amoeba that’s present.
“If we were to sample freshwater lakes, hot springs, rivers, the amoeba would be present in them, especially in this area of the country,” said Fred Lopez, an infectious disease specialist at LSU Health Sciences Center in New Orleans.
But why some people fall ill and others do not is a question without easy answers.
“This is not a common infection, and why it is that all those other millions of people who jump in these bodies of water don’t develop infections, I think is the critical issue,” Lopez said.
The two Louisiana residents who died of the fatal brain infection in 2011, including a St. Bernard man, became sick after using contaminated tap water in neti pots to irrigate their sinuses. State health officials responded by warning residents to use distilled or boiled tap water in the teapot-like containers, to avoid the risk of contracting the disease.
“If it was inside the nostril, that’s no big deal. It has to be pushed all the way to the brain,” said Raoult Ratard, the state epidemiologist for the state health department.
While more cases have come to light, Ratard said that’s because technology has improved, not because the amoeba is becoming more widespread.
“In this case, 10 years ago, nobody would know the cause, but now we know because we have better techniques for identifying amoebas,” he said.
Peralta on Friday declined to disclose the location of the home where the boy became infected, saying only that it is near Violet and that it was not near where the last person became infected in St. Bernard two years ago.
There, Peralta blamed the neti pot, which he said was “filled with water, and it was allowed to sit for a very long period of time.”
This time, Peralta speculated that the amoeba in the toilet tank suggested that the home had seen little activity for some time.
“You’re constantly using water, you’re constantly flushing your systems, so you’re not going to get a lot of stagnant water,” he said.
The 4-year-old’s cause of death was primary amebic meningoencephalitis, a rare form of meningitis caused by the amoeba getting into the brain, destroying delicate tissue, causing swelling and — almost surely — death in a matter of days.
Symptoms are mild at first, about five days after infection, including headache, fever, nausea, vomiting and a stiff neck. Within days they grow more severe, adding confusion, a lack of attention to people and surroundings, loss of balance, seizures and hallucinations. Rapidly, the disease progresses, usually in less than two weeks.
Lopez emphasized that the infection is “extremely low-risk, in terms of acquiring it.”
“Many people are jumping in the same bodies of water and not getting infected,” he said. Nose clips could help keep nasal passages closed, he suggested, or swimmers in ponds and streams can keep their heads above water.