Brain-Eating Amoeba

NDSU Microbiology
by NDSU Microbiology

Guest Blogger, Chris Molitor, VMS Undergrad

I spend most of my summertime on Grand Lake in Minnesota. Swimming, water skiing, and hanging out on the pontoon are just the beginning of the activities I like to do with my family and friends. I never thought we had anything to worry about, until a news article was released in 2010. A boy from Stillwater, Minnesota passed away after swimming in a local lake. A tiny parasite, invisible to the naked eye, entered his body and killed him.

This tiny amoeba is known as Naegleria fowleri and is present in lakes all over the United States, from Florida to California, and even as far north as Minnesota. The parasite enters through the nose and
migrates to the brain through the olfactory nerves. Once in the brain, N. fowleri destroys brain tissue. This condition is referred to as primary amebic meningoencephalitis (PAM), and those infected have a very low survival rate; 98% of people infected with this parasite die within 2 to 20 days after exposure.

This, of course, got me thinking. There is a good chance that I swim with the parasite on a regular basis; however, my chance of infection remains very low because the parasite is only infectious when environmental conditions are favorable. When the water is warm, the harmless cyst transforms into what is called a trophozoite. It is during this stage that the parasite can enter through the nose and infect humans. Since 2004, only 34 cases of PAM have been reported. This number is insignificant compared to the hundreds of thousands of recreational water exposures.

Even though infection is rare, we still need to help those who become infected. For years there was no treatment for PEM, but there have been recent advancements that have helped those infected. In the summer of 2013, a 12-year-old girl was diagnosed with PAM 30 hours after showing signs of sickness. She was quickly treated with the investigational drug, milefosine, and her brain swelling was managed by cooling her body below normal body temperature. She was the first person to be diagnosed with PAM and make a full recovery.

Learning that my lake might have N. fowleri has never stopped me from enjoying my summers on the lake. I understand that the odds of getting infected are extremely low, but those who are worried about infection can take some precautions. The parasite enters through the nose, so simply wearing nose plugs can prevent it from entering.

Anyone who loves to spend their summers on lakes across America can do so safely by being aware of N. fowleri.

Image: CDC

This entry is part of the MICR 354 (Scientific Writing) student-blog series.