Naegleria fowleri is a brain-eating amoeba that lives in warm freshwater (such as lakes, rivers, hot springs, and ponds). It can enter the human body through the nostrils and be potentially life threatening. Naegleria fowleri causes the disease Primary Amebic Meningoencephalitis (PAM), a brain infection that leads to the destruction of brain tissue. While the condition is rare (120 reported cases since the amoeba was identified in 1960), there have been three reported cases in the summer of 2011 . According to the Centers for Disease Control and Prevention (CDC), infections are most likely to occur when it is hot for prolonged periods of time. Heat waves cause higher water temperatures and lower water levels. ACA has compiled the following information to help camps understand the issues.
Top Four Tips for Camps
- Understand that while extremely rare, three cases of Naegleria fowleri causing Primary Amebic Meningoencephalitis have been reported in 2011. Educate yourself about the facts so you will be informed should questions arise. (See below.)
- Recognize that Naegleria fowleri is most commonly found in freshwater lakes in southern-tier states during the summer, and that infections are most likely to occur when the weather is hot for prolonged periods of time. Asses risk when utilizing your freshwater lake, pond, or river. (See below.)
- If any camper or staff person shows signs of headache, fever, nausea, vomiting, or stiff neck, seek immediate medical attention.
- 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.
Naegleria fowleri is most commonly found in freshwater lakes in southern-tier states during the summer. According to the CDC, this means that freshwater users should be aware that there will always be a low-level risk of infection when entering these waters. In very rare instances, Naegleria fowleri has been identified in water from other sources (such as an inadequately chlorinated swimming pool water or heated tap water less than 47°C). There is no rapid or routine test to determine if Naegleria fowleri is present in the water (the tests that are available can take weeks), but new detection tests are under development.
Contracting the Infection
As stated above, while infections with Naegleria fowleri are very rare, they have occured mainly during the summer months of July, August, and September. Infections have been more likely to occur in southern-tier states of the US, but can also occur in other locations. As noted previously, 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. The organism thrives on the nutrients in the organic sediment in a body of freshwater. The level of phosphorus and nitrogen in organic sediment is typically about a thousand times the level found in the water column. When stirred, Naegleria fowleri are free floating. The Naegleria fowleri amoebae then swim up a swimmers nose, burrow into the brain and eat it rapidly. Infection cannot be spread from one person to another, and you cannot be infected with Naegleria fowleri by drinking contaminated water.
Initial symptoms of PAM start one to seven 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 can cause death within one to twelve days.
If a camper or staff person develops a sudden onset of fever, headache, stiff neck, or vomiting, trained medical care should be immediately secured. While clinical studies have shown that several drugs are effective against Naegleria fowleri in the laboratory, their effectiveness is unclear since almost all infections have been fatal, even when people were treated.
Since, according to the CDC, 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 t