Not all living creatures die. An amoeba, for example, need never die; it need not even, like certain generals, fade away. It just divides and becomes two new amoebas - George Wald
The organism responsible, Naegleria fowleri, dwells in warm freshwater lakes and rivers and usually targets children and young adults. Once in the brain it causes a swelling called primary meningoencephalitis. The infection is almost universally fatal: it kills more than 97 percent of its victims within days.
Although deadly, infections are exceedingly uncommon—there were only 34 reported in the U.S. during the past 10 years—but evidence suggests they may be increasing. Prior to 2010 more than half of cases came from Florida, Texas and other southern states. Since then, however, infections have popped up as far north as Minnesota.
“We’re seeing it in states where we hadn’t seen cases before,” says Jennifer Cope, an epidemiologist and expert in amoeba infections at the U.S. Centers for Disease Control and Prevention. The expanding range of Naegleria infections could potentially be related to climate change, she adds, as the organism thrives in warmer temperatures. “It’s something we’re definitely keeping an eye on.”
Still, “when it comes to Naegleria there’s a lot we don’t know,” Cope says—including why it chooses its victims. The amoeba has strategies to evade the immune system, and treatment options are meager partly because of how fast the infection progresses.
But research suggests that the infectioncan be stopped if it is caught soon enough. So what happens during an N. fowleri infection?
The microscopic amoebae, which can be suspended in water or nestled in soil, enter the body when water goes up the nose. After attaching to the mucous membranes in the nasal cavity, N. fowleri burrows into the olfactory nerve, the structure that enables our sense of smell and leads directly to the brain. It probably takes more than a drop of liquid to trigger a Naegleria infection; infections usually occur in people who have been engaging in water sports or other activities that may forcefully suffuse the nose with lots of water—diving, waterskiing, wakeboarding, and in one case a baptism dunking.
It turns out that "brain eating" is actually a pretty accurate description for what the amoeba does. After reaching the olfactory bulbs, N. fowleri feasts on the tissue there using suction-cup-like structures on its surface. This destruction leads to the first symptoms—loss of smell and taste—about five days after the infection sets in.
From there the organisms move to the rest of the brain, first gobbling up the protective covering that surrounds the central nervous system. When the body notices that something is wrong, it sends immune cells to combat the infection, causing the surrounding area to become inflamed. It is this inflammation, rather than the loss of brain tissue, that contributes most to the early symptoms of headache, nausea, vomiting and stiff neck. Neck stiffness in particular is attributable to the inflammation, as the swelling around the spinal cord makes it impossible to flex the muscles.
As N. fowleri consumes more tissue and penetrates deeper into the brain, the secondary symptoms set in. They include delirium, hallucinations, confusion and seizures. The frontal lobes of the brain, which are associated with planning and emotional control, tend to be affected most because of the path the olfactory nerve takes. “But after that there’s kind of no rhyme or reason—all of the brain can be affected as the infection progresses,” Cope says.
Ultimately what causes death is not the loss of grey matter but the extreme pressure in the skull from the inflammation and swelling related to the body’s fight against the infection. Increasing pressure forces the brain down into where the brain stem meets the spinal cord, eventually severing the connection between the two. Most patients die from the resulting respiratory failure less than two weeks after symptoms begin.
The threat of contracting an N. fowleri infection is remote (vastly more people die every year from drowning), but you can take some measures to lower your risk even further. Cope recommends using nose plugs and not immersing your head fully under water when swimming. She also counsels against kicking up sediment, which can shake the amoeba loose.
More effective treatments may be on the horizon. Last year, the U.S. Food and Drug Administration approved Miltefosine, originally intended as an anti-cancer treatment. In 2013, two people in the U.S. survived N. fowleri when they took the drug (and others) soon after being infected.
And last month, scientists sequenced the amoeba’s genome for the first time. Their insights may help us understand what makes it so virulent and point the way to better treatments.
Source: Roni Jacobson, Excerpt from What Happens When an Amoeba “Eats” Your Brain? Scientific American, July 18, 2014.
Miltefosine is exciting for a couple of reasons. Unlike Amphotericin, it can be given by mouth. This is critically important in less-affluent countries like Pakistan, which has more frequent cases of Naegleria. The infection occurs more often from ritual nasal irrigations, commonly done with unchlorinated water.
Composed of a single cell, amoeba seem harmless enough: They look like playful critters waltzing under the spotlight of a microscope until they come upon a group of bacteria. Then, these previously innocuous amoeba suddenly morph into sinister blobs, engulfing the bacteria and slowly ripping them apart with a bevy of digestive enzymes. It’s hard to cry over murdered bacteria, but the digestive power of amoeba is the stuff of nightmares when it plays out in a human brain.
The single-celled menace rarely infects humans. That’s what makes it so hard to treat.
N. fowleri dwells in warm bodies of fresh water where it dines on bacteria in the sediment. As such, most infections with this amoeba in the U.S. have occurred in southern states, especially Texas and Florida, during the summer. When the sediment of a lake is disrupted, amoeba get stirred into the water. Swimmers can then inhale the parasite through their nose. From there, N. fowleri invades the olfactory nerves and migrates to the brain, where it causes a dangerous condition called primary amoebic meningoencephalitis.
In this short video he discusses Naegleria as a reportable disease, Naegleria risk and prevention for the public, public health policy and recommendations for the hospital emergency room.
Dr Dumois shared his thought on why the rapid diagnosis of Naegleria is so challenging, he briefly discussed the primary amoebic meningoencephalitis (PAM) protocol used in his facility and the importance of keeping the drug, miltefosine readily available in the hospital.
Not only are brain-eating amoebas (Naegleria fowleri) real and deadly, but there have been multiple cases of people contracting the amoeba while using neti pots.
First discovered in 1899, Naegleria fowleri is a
protist pathogen, known to infect the central nervous
system and produce primary amoebic meningoencephalitis.
The most distressing aspect is that the fatality rate
has remained more than 95%, despite our advances in
antimicrobial chemotherapy and supportive care.
The Food and Drug Administration last month reported on two cases in Louisiana in which patients contracted infections after using neti pots filled with tap water. The culprit was an amoeba called Naegleria fowleri, which is commonly found in lakes, rivers and hot springs.
Just what is the brain-eating “Amoeba” Naegleria fowleri?
While playing on a Slip ‘n Slide in New Orleans, a 4-year-old may have snorted water—and a deadly brain-eating organism. Dr. Kent Sepkowitz on the alienlike amoeba that gives him nightmares.
If you go in the water, Yoder suggests not submerging your head. If you do, wear a nose clip. "In some ways they make common sense," he says. "Anything you do to reduce the risk of water being forced up your nose, probably reduces the risk of infection."
Oh, and lay off the neti pots, unless you plan on sterilizing your water beforehand.
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. 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 Naegleria fowleri, the so-called brain-eating amoeba, may be on the rise--here’s what you should know about the deadly organism.
To create global awareness about the risks associated with amoebas in fresh warm water and educate families and medical communities about the risks from Naegleria fowleri and Primary Amoebic Meningoencephalitis (PAM).
Kyle passed away August 29, 2010 from PAM caused by Naegleria Fowleri...we are spreading the awareness so others can protect their loved ones!
Swim Above Water was formed to initiate conversation and awareness in our community about Naegleria Fowleri, a free living microscopic amoeba and the infection It causes called Primary Amoebic Meningoencephalitis (PAM). Our goal is to educate you on the risks associated with freshwater activities and how to prevent exposure to this deadly amoeba.
N. fowleri is a free-living amoeba capable of devouring your brain! This insidious creature makes its home as a flagellated amoeboid in characteristically warm freshwater sites such as lakes, rivers, geothermal hot springs, warm water discharge from industrial plants, poorly maintained and minimally-chlorinated or unchlorinated swimming pools and Jacuzzis.
4.While not a guarantee, the CDC recommends the following preventive measures when swimming in warm bodies of freshwater: avoid water-related activities in warm freshwater during periods of high water temperature and low water levels; hold the nose shut or use nose clips when taking part in water-related activities in bodies of warm freshwater;
avoid digging in, or stirring up, the sediment while taking part in water-related activities in shallow, warm freshwater areas.
Signs and symptoms of Naegleria fowleri infection are clinically similar to bacterial meningitis, which lowers the chances of initially diagnosing PAM. Humans become infected when water containing Naegleria fowleri enters the nose and the ameba migrates to the brain along the olfactory nerve. People do not become infected from drinking contaminated water.
Some factors that might increase your risk of naegleria infection include:
•Freshwater swimming. Most people who become ill have been swimming in a freshwater lake within the past two weeks.
•Heat waves. The amoeba thrives in warm or hot water.
•Age. Children and young adults are the most likely age groups to be affected, possibly because they're likely to stay in the water longer and are more active in the water.
Naegleria fowleri is an amoeba that lives predominately in warm freshwater.
Naegleria fowleri is acquired by people when infected water is forcibly aspirated into the nose. This can occur through recreational swimming, diving, or during sports like water skiing.
Once acquired, the amoeba travels into the brain, causing primary amoebic meningoencephalitis (PAM). In the popular press, Naegleria fowleri is sometimes called the
"brain-eating amoeba," and meningoencephalitis is sometimes referred to as Naegleriasis.
PAM is very rare, and there are only a few cases reported each year in the United States.