Naegleria fowleri is a parasite that lives in freshwater and can infect swimmers, and this year two high-profile cases involving children have led to a spotlight on the rare but very fatal amoeba.
Known by scientists as a brain-eating amoeba, Naegleria fowleri has struck twice this summer in young swimmers. In Little Rock, Arkansas, a 12-year-old girl was infected as she swam in a sandy-bottom lake at a water park. This month another swimmer, a 12-year-old boy, contracted the parasite while kneeboarding in a ditch near his home.
Naegleria fowleri is almost always deadly, with only two known cases of survivors, but the girl stricken in Arkansas appears to be on the road to recovery. She has been released from intensive care, a spokesperson at Arkansas Children's Hospital said.
In an interview with National Geographic Daily News, researcher Justin Yoder explained that Naegleria fowleri is a very deadly parasite that appears to be migrating further northward.
Yoder, an epidemiologist at the Centers for Disease Control, said the parasite can develop threadlike structures that allow it to swim toward more favorable conditions. When people swim in warm freshwater during the summer, this can mean the amoeba swimming up their nose into the brain.
Those stricken with Naegleria fowleri experience headaches, sore neck, and vomiting that becomes more severe. Infections will eventually lead to a coma, and the vast majority of patients die within five days.
Yoder said there are generally four or five cases in the United States per year, but they're starting to show up in different places.
"What has changed recently is that cases have appeared in places we had never seen before --- like Minnesota, Indiana, and Kansas," he said. "This is evidence that the amoeba is moving farther north. In the past it was always found in warmer weather states."
He added that though infections are rare, there are some precautions swimmers can take to protect themselves.
"If people want to reduce their risk of becoming infected --- even though this is a rare event --- the thing to think about is holding their nose shut or wearing nose clips when swimming in warm, untreated freshwater," Yoder said. "Keep your head above water in hot springs or other thermally heated bodies of water, and during activities where water is forced up the nose, like water sports and diving."
Infections from the brain-eating amoeba have broken out elsewhere as well. Last year, 10 people in Pakistan died after contracting Naegleria fowleri from infected water.