Ameba: Naegleria fowleri in the U.S.
Have you ever heard of Naegleria fowleri? I’ve heard of it before, but I never really paid much attention to the ameba until now. We’re about to head to Florida for a summer vacation, and the grandkids will be going with us. I’m not usually careful enough when it comes to my own safety, but with the grandkids, I can be somewhat of a safety stickler. If you’re a grandparent, I’m sure you can relate. Anyway, Naegleria fowleri is pretty widespread in the Sunshine State, even though infections caused by the ameba are rare. When they do occur, however, they’re almost always fatal. Information like that can certainly make a concerned grandparent or parent sit up and pay attention. I’ve always believed that knowledge is power, so I’ve been studying this brain eating amoeba, finding out as much about it as I could. One problem with this is that scientists don’t really know a lot about Naegleria fowleri or how to treat Primary Amoebic Meningoencephalitis, and in my opinion, that makes the amoeba even scarier. I mean, when the experts don’t even fully understand a topic in their field of study, how is the average person supposed to understand it and take the proper safety precautions? In this article, I’m sharing with you what I’ve learned about Naegleria fowleri, along with a few travel tips and other safety tips.
Let’s begin with a little information about ameba, in general. I’ll start with the spelling of the term. When I was in school, we spelled it amoeba. Now, however, it seems that in the United States, the proper spelling is ameba. In the UK, it’s still amoeba. I don’t know…maybe the grade schools I attended in South Georgia just preferred the UK spelling.
Anyway, an ameba is a one-celled organism with an irregular shape. The plural of amoeba is amoebae, and the plural form of ameba is amebas or amoebae. This gets rather confusing, doesn’t it? Amebas live in water or in some other fluid, and in soil. The ameba has a cell nucleus – sometimes more than one. The cytoplasm, the jelly-like inside of the cell, is surrounded by the cell membrane. The fluid within the cell of the amoeba is controlled by a contractile vacuole, and food is stored in food vacuoles. Amebas are capable of movement, by using “false feet,” called “pseudopods.” To move, one of the false feet is stretched out, and the rest of the cell changes shape in order to follow. Food is obtained in a similar fashion. When the ameba finds a particle of food, the cell surrounds it and devours it. Amoebae eat bacteria, along with algae and other types of phytoplankton. To reproduce, amebas use nuclear division, or mitosis.
Amoebae can be harmful to humans and animals when the tiny organisms enter the body. Across the globe, tens of thousands of human deaths are caused by amoebae each year. When swallowed, amebas can cause damage to the intestines, the liver, and other organs. When the amebas enter the host through the nose, they can damage the brain, as is the case with the brain eating amoeba, Naegleria fowleri.
Brain Eating Amoeba
A brain eating amoeba?? That sounds sort of like a good name for a low budget horror film, doesn’t it? Unfortunately, however, it’s all too real. The term used to describe this condition is Primary Amoebic Meningoencephalitis, or PAM, for short. How does this happen? Believe it or not, the amebas, Naegleria fowleri, don’t cause destruction of brain tissue when swallowed. Instead, the danger occurs when the amebas enter the victim’s nose. From there, they travel to the brain via the olfactory nerve, which leads to the brain’s frontal lobe. The brain is a great environment for the invading amebas, where they find moisture, warm temperatures, shelter, and food. Once there, the amebas don’t find their usual food source, bacteria, so they feed on brain tissue, instead. The amebas use enzymes to dissolve brain tissue, turning it into a food source. They make a small opening in the brain cells and feed on the escaping contents.
Naegleria fowleri is often referred to as a brain eating amoeba. It lives in warm freshwater bodies of water, including ponds, lakes, and untreated swimming pools, along with damp soil. Some scientists once thought that it could survive only in stagnant water, but that’s been proven false. It’s also been found in rivers and in natural springs. Some scientists have also speculated that the amebas live only in the silt on the bottom of a body of water, but it’s been found in every level of the water column, although it is usually more prevalent in the silt. Another incorrect assumption is that Naegleria fowleri can live only in very warm climates. In the United States, this would include the southernmost states. Here’s a news flash: the ameba has been found as far north as Minnesota. It is, however, more common in southern states where summers get extremely warm, including Florida and Texas.
Naegleria fowleri are microscopic, about ¼ the size of a human hair’s diameter. They were originally found and identified in Australia, but many scientists think the amoeba actually evolved elsewhere – most likely in the United States. They can be found all across the globe, anywhere there’s warm freshwater: lakes, ponds, rain puddles, aquariums, rivers, streams, and natural springs. Alarmingly, Naegleria fowleri has also been found in hot tubs, swimming pools, wells, and city water systems.
Meningoencephalitis is an inflammation of the brain and the meninges. The meninges are the protective membranes that cover the brain and the spinal cord. You’ve heard of meningitis, an inflammation of the meninges. You’ve also heard of encephalitis, an inflammation of the brain. Think of meningoencephalitis as sort of a combination of these two other medical conditions.
Meningoencephalitis causes are numerous and varied. It can be caused by bacteria, including Rickettsia prowazekii, Listeria monocytogenes, and Neisseria meningitidis. These bacteria can be spread by lice, by contaminated foods, and through body fluids of infected individuals, respectively.
Other causes of meningoencephalitis are viruses: mumps, HIV, herpes simplex I, and West Nile. Ticks can also carry a virus that causes the disease. Spores from the fungus Cryptococcus neoformans can also cause meningoencephalitis. Protozoa that can cause the condition include Toxoplasma gondii and Trypanosoma brucei, along with several protozoa that cause Primary Amoebic Meningoencephalitis, or PAM, including Naegleria fowleri.
Not everyone who is exposed to Naegleria fowleri develops meningoencephalitis or PAM. It appears that many individuals have a natural resistance, and PAM cannot be spread from person to person. For some reason, most victims are male, and over half are children. Doctors and scientists aren’t even sure how many people are affected by PAM each year. Because the symptoms are very similar to those presented with meningitis, some patients are diagnosed with meningitis when, in fact, they have Primary Amoebic Meningoencephalitis.
Primary Amebic Meningoencephalitis:
As I’ve already mentioned, the symptoms of meningoencephalitis are similar to the symptoms of meningitis. These include pain or stiffness in the neck, headache, nausea and vomiting, and fever. I had meningitis as a child, and these were the exact symptoms I experienced. I can still remember how badly my neck and head hurt. Other meningoencephalitis symptoms might include a sore throat, a drooping eyelid, changes in taste or smell, diarrhea, confusion, hallucinations, coma, or seizures.
Meningoencephalitis symptoms can show up as quickly as two days after the amoeba has entered the body, or it might take as long as two weeks for symptoms of meningoencephalitis to manifest. The usual incubation period is three to six days. PAM is a deadly disease that only one known confirmed victim in the United States has survived. Scientists have found drugs that eliminate Naegleria fowleri in laboratory conditions, but they don’t seem to work in actual humans. That’s why prevention is so important.
If you’re planning a trip to an area where Naegleria fowleri is present, use some travel tips that will help ensure the safety of you and your family. Of course, it’s best to completely avoid swimming, diving, or snorkeling in any freshwater body, but since most Americans love water sports, that’s not likely to happen. When you do get in any type of untreated warm freshwater, keep your head above water at all times, or at least use a clip that keeps your nostrils shut tightly, or plug your nostrils with nose plugs. Because many scientists believe that higher concentrations of Naegleria fowleri are found in the mud at the bottom of the water, it’s best not to disturb it. Also, when you’re using a neti pot with water that you’re not sure is safe, boil the water first for four or five minutes. Naegleria fowleri can survive at temperatures to only around 113-114 degrees, so bringing the water to the boiling point should kill any amoeba. Also, think twice before swimming in strange swimming pools and getting in strange hot tubs, and if you have your own, make sure the water is treated with the proper chemicals.
Fortunately, you don’t have to worry about these travel tips if you’re swimming in the ocean or some other body of saltwater. Naegleria fowleri can’t survive in saltwater. I found this fact very comforting, as most of our vacations take place near the Atlantic Ocean or the Gulf of Mexico, and all my family members enjoy swimming, boogie boarding, and snorkeling. If, on the other hand, you’re considering enjoying a dip in warm freshwater, use safety precautions to avoid any possible Naegleria fowleri amoeba and a resulting case of meningoencephalitis.