Water is supposed to offer a fun way to cool off when it is hot outside – and most of the time it does. But be aware that in lakes, streams, rivers and ponds, there is an amoeba – Naegleria fowleri – that can cause a rare but usually fatal illness – Primary Amebic Meningoencephalitis – or PAM. Fortunately, there are ways you can take precautions to stay safe and still enjoy the water.

Confirmed reports of this infection are very uncommon. It occurs when water enters the nose, and the amoeba travels to the brain. The US Centers for Disease Control and Prevention notes that the amoeba can be present in freshwater areas like rivers or lakes, but there are very rare instances of the organism surviving in inadequately chlorinated swimming pools or contaminated tap water. The CDC notes that people can’t be infected from swallowing water, and the disease cannot be spread from person to person. The infection only occurs when water enters the nose, and the amoeba is present.

The Texas Department of State Health Services (TDSHS) reports that the majority of PAM infections nationwide take place in July, August, or September, when the temperature is often hottest, and water levels are lower. While the amoeba is found around the world, it thrives in warm water with a temperature of at least 80 degrees. However, it is not found in salt water. It can also be found in sediment near the water. The CDC reports that from 2006-2015, there were 37 PAM infections reported in the United States, with 33 of those resulting from contaminated recreational water, and four cases from contaminated tap water. The TDSHS says that while the amoeba is a concern, the risk of drowning is far greater than of being affected by PAM.

According to the CDC, initial symptoms begin about five days after infection, but can start as early as one day and as late as nine days after infection. These symptoms may include headache, fever, and nausea at first. Later symptoms can include a stiff neck, confusion, loss of balance, seizures and hallucinations. The disease progresses rapidly and usually results in death within one to five days. The fatality rate is 97 percent, based on statistics from the CDC for 1962-2016.  Four people known to have this infection (out of 143 total) in the U.S. have survived.

One of the victims of PAM in Texas was Kyle Lewis, a 7-year-old boy from Arlington who died after a swimming trip with his family to the Brazos River basin that included time in Glen Rose as well as Lake Granbury. Lewis’ family has founded the Kyle Cares Amoeba Awareness charity to help people be alert to the dangers of PAM.

Several drugs have proven to be effective against the amoeba in laboratory tests. The CDC notes that in recent years, two people survived the infection after being treated with miltefosine in combination with other drugs and efforts to reduce brain swelling. Cook Children’s Medical Center in Fort Worth has miltefosine on site to treat patients diagnosed with PAM. Most importantly, a fast and accurate diagnosis of the infection is extremely important.  Those experiencing symptoms should see a physician or visit an emergency room immediately. The physician should be informed that the patient has taken part in activities in warm surface water.  The disease has mistakenly been diagnosed as the flu or meningitis. Providing the physician with information that the patient has been swimming in surface water will allow for appropriate testing to be undertaken quickly. 

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One way to greatly reduce the risk of being infected is to avoid submerging your head when swimming in fresh water. Nose plugs can also offer an effective safeguard. The only way to completely reduce the risk is to avoid all freshwater activities. But using nose clips or a swimming mask, holding your nose while going underwater or simply not going underwater offers a way to greatly decrease the chance of infection while still allowing you to enjoy water activities. Also, avoid digging or stirring up sediment in the water.

The TDSHS reports that from 1972 to 2016, a total of 34 cases of PAM have been reported in Texas. The median age of those infected was 9.5 years, with reports of people ranging in age from 3 to 37 infected. The infections have taken place from July to November, with August being the most common month for PAM infections.

For more information about PAM, go here or contact the Texas Department of State Health Services Public Information Office at (512) 458-7400. More information about the Kyle Cares outreach can be found here.