by Maria Teresa L. Ungson
Have you heard of naegleria fowleri? Just recently, two young people have died in the US after being infected with this “brain eating amoeba.” Let me share with you information about this amoeba so we can avoid contracting this infection.
Naegleria is an amoeba (single-celled living organism) commonly found in warm freshwater (for example, lakes, rivers, and hot springs) and soil. Only one species (type) of Naegleria infects people: Naegleria fowleri.
Naegleria fowleri infects people by entering the body through the nose. This typically occurs when people go swimming or diving in warm freshwater places, like lakes and rivers. The Naegleria fowleri amoeba travels up the nose to the brain where it destroys the brain tissue.
You cannot be infected with Naegleria fowleri by drinking contaminated water. In very rare instances, Naegleria infections may also occur when contaminated water from other sources (such as inadequately chlorinated swimming pool water or heated tap water <47°C) enters the nose, for example when people submerge their heads or cleanse during religious practices, and, possibly, when people irrigate their sinuses (nose).
Naegleria fowleri is found around the world. In the United States, the majority of infections have been caused by Naegleria fowleri from freshwater located in southern-tier states. The amoeba can be found in: 1) bodies of warm freshwater, such as lakes and rivers, 2) geothermal (naturally hot) water, such as hot springs, 3) warm water discharge from industrial plants, 4) geothermal (naturally hot) drinking water sources, 5) soil, 6) swimming pools that are poorly maintained, minimally-chlorinated, and/or un-chlorinated and 7) water heaters with temperatures less than 47°C.
Naegleria fowleri is not found in salt water, like the ocean. Likewise, one cannot get a Naegleria fowleri infection from a properly cleaned, maintained, and disinfected swimming pool.
While infections with Naegleria fowleri are very rare, they occur mainly during the months of July, August, and September. Infections are more likely to occur in southern-tier states, but can also occur in other locations. Infections usually occur when it is hot for prolonged periods of time, which causes higher water temperatures and lower water levels. Infections can increase during heat wave years.
Naegleria fowleri causes the disease primary amebic meningoencephalitis (PAM), a brain infection that leads to the destruction of brain tissue. In its early stages, symptoms of PAM may be similar to symptoms of bacterial meningitis.
Initial symptoms of PAM start 1 to 7 days after infection. The initial symptoms include headache, fever, nausea, vomiting, and stiff neck. Later symptoms include confusion, lack of attention to people and surroundings, loss of balance, seizures, and hallucinations. After the start of symptoms, the disease progresses rapidly and usually causes death within 1 to 12 days.
Several drugs are effective against Naegleria fowleri in the laboratory. However, their effectiveness is unclear since almost all infections have been fatal, even when people were treated. Naegleria fowleri infection cannot be spread from one person to another.
Infection with Naegleria fowleri is very rare. The early symptoms of Naegleria fowleri infection are more likely to be caused by other more common illnesses, such as meningitis. People should seek medical care immediately whenever they develop a sudden onset of fever, headache, stiff neck, and vomiting, particularly if they have been in warm freshwater recently.
Recreational water users should assume that there is always a low level of risk whenever they enter warm freshwater (for example, when swimming, diving, or waterskiing) in southern-tier states. Naegleria fowleri is found in many warm freshwater lakes and rivers in the United States, particularly in southern tier states. It is likely that a low risk of Naegleria fowleri infection will always exist with recreational use of warm freshwater lakes, rivers, and hot springs. The low number of infections makes it difficult to know why a few people have been infected compared to the millions of other people using the same or similar waters across the U.S. The only certain way to prevent a Naegleria fowleri infection is to refrain from water-related activities in or with warm, untreated, or poorly-treated water.
If you do plan to take part in water-related activities, some measures that might reduce risk include:
• 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.
