Amoeba (Naegleria fowleri) showing the feeding structures or pseudopods that form a face-like appearance. This freshwater protozoan parasite causes a type of amebiasis infection that is usually fatal called primary amebic meningoencephalitis. SEM

“Brain-eating amoeba found in water supply.”


WHOA! What may sound like the plot line to an upcoming horror flick has actually been the news headlines across some areas of south Louisiana over the past few weeks after several parishes around Baton Rouge and New Orleans were found to have public water systems that tested positive for an ameba.  Before you start stocking up on bottled water or heading North, here is what you need to know about this ameba and the rare illness it can cause.

Just what is the organism causing all the concern?

Naegleria fowleri is an ameba, which means it is a single-cell living organism, that is microscopic in size and was originally discovered in 1965 in Australia.  This ameba loves warm water and is therefore commonly found in Southern climates in warm, freshwater environments such as lakes, rivers, and hot springs.  Although less common, Naegleria can also be found in improperly treated swimming pools during hot summer months and in public drinking water that does not have the appropriate chlorine levels.  Naegleria cannot live in salt water which is why the ocean is not one of their habitats.

What type of infection does this ameba cause?

Well, here is where the “brain-eating” headline comes into play.  Naegleria causes primary amebic meningoencephalitis (PAM) which is a severe and often deadly brain infection.  The ameba can only cause this infection though by entering the brain through the nose.  When contaminated water enters the nose, often forcefully as in diving, Naegleria follows along the nerves of the nose and enters the brain through the bones and cartilage of the nose.  Once in the brain, the ameba destroys brain tissue which often leads to swelling and death.

WOW! That sounds scary!! How common is this infection?

PAM from Naegleria is VERY rare! There have been 35 reported cases from 2005-2014 here in the US.  Of these, 1 occurred in a child after playing on a slip-n-slid that used contaminated tap water, 3 occurred after sinus rinses with contaminated tap water, and the remainder occurred after recreational water use (such as swimming, diving, etc) in contaminated lakes or rivers.  While each of these infections is significant, we must remember just how many millions of people have been in these warm, freshwater environments over that same 10 year time period.  At this time scientist are not sure why one person could come down with this infection while a person who was swimming right next to them in the same warm body of water would not become infected.

Is there any other way this ameba causes infection?

No.  You cannot get PAM by drinking water contaminated with Naegleria or if contaminated water touches your skin.  Naegleria infections also can’t be passed from person to person.

What are the symptoms of PAM?

The early symptoms of PAM caused by Naegleria will look very similar to bacterial or viral meningitis.  This includes sudden onset of fever, headache and nausea or vomiting.  The symptoms can then progress quickly to stiff neck, change in behavior, confusion and seizures.  The early symptoms of PAM typically occur within 1-5 days of the ameba entering the body.  Prompt medical evaluation is, of course, indicated if you or your child ever begin having such symptoms especially after swimming in a lake or river.

Is there any treatment for PAM?

Scientist are working on this one, but until recent years, the answer was no.  This infection has a 97% mortality rate…there have only been 3 survivors between 1962 and 2014.  A new, experimental drug called miltefosine was given along with other aggressive treatment measures in two recent cases in which people did survive.

How can you prevent Naegleria infection?

At this time there is no way to “treat” bodies of water such as lakes in order to eliminate the presence of the Naegleria ameba.  While most people who are exposed to Naegleria will not come down with PAM (again, think about how many millions of people swim in lakes, rivers and hot springs each year while there are generally only 3-4 cases of PAM during that time), there are several steps you can take to reduce the risk of such infections.  All of these measures focus on limiting the amount of water that gets into the nasal cavity.

  • When swimming in freshwater lakes, rivers or streams, try not to jump or dive head first into the water
  • Make sure and plug the nose if your head is going to be submerged for any amount of time
  • Wear either a nose plug or a face mask that protects the nose especially when doing water sports such as skiing, knee boarding or tubing on warm, freshwater lakes or rivers.
  • Keep the head above water in especially warm bodies of water such as hot springs
  • Avoid disturbing the sediment on the bottom of shallow rivers or lakes as Naegleria can often be found in the soil in these areas

So what other steps should be taken by those who live in an area serviced by a contaminated public water supply?

To start, parishes where the ameba has been found in recent weeks are all taking steps to rid the water supply of Naegleria by doing a chlorine burn (basically adding enough chlorine to the water to get the water to meet chlorine standards and therefore, rid the water of Naegleria).  Here are a few other considerations when it comes to contaminated tap water:

  • When showering or bathing, do not sniff water into the nose
  • For parents, when bathing young children or infants, make sure they are supervised at all times to ensure they are not putting their face into the bathwater.  Also, when rinsing shampoo from their hair, either cover your child’s nose or gentle squeeze the nostrils closed when pouring the water over them.
  • Do not allow children to play in sprinklers or use hoses to cool off.  Also, do not allow children to play in kiddie pools that have been filled with water from the hose or play on slip-n-slides using water from the hose.
  • If using tap water for any kind of nasal irrigation or sinus rinse, make sure to boil the tap water for 1 minute (and then allow it to cool) before using it in irrigation solutions.  An alternative to tap water for sinus rinses would be to use distilled or sterile water that is purchased from the store (I think this really is the way to go for everyone).

While something like Naegleria and the devastating PAM that it can cause is very scary to hear about, it is important to remember just how rare such infections are here in the US.  To get the most up to date information in regards to specific public water districts here in Louisiana, click here to go to the Louisiana Department of Health and Hospitals website.  You can also click here for more information on Naegleria and PAM from the Center for Disease Control.