Just how rare is the brain-eating ameba reported in Arlington? What to know

Arlington’s Don Misenhimer Park made headlines Monday, after the city announced a child died Sept. 11 from a rare brain-eating ameba he likely encountered at the park splash pad.

The central nervous disease, primary amebic meningoencephalitis, has a death rate over 97%, with only four of the 148 people in the U.S. to have survived the disease. The brain-eating ameba that causes the disease lives in warm freshwater and is more prevalent in the southern part of the county. Texas and Florida have documented the most cases between 1962 and 2020, according to the Centers for Disease Control and Prevention.

The statistic makes sense: Texans have more than 150 lakes and even more options to swim for a respite from the summer swelter. Even so, the disease is extremely rare, with the CDC reporting up to eight infections per year, if at all. Swimmers are much more likely to drown than become infected.

In case those statistics do not put your mind at ease, the Star-Telegram has gathered facts about the disease and how to safeguard against an unlikely infection.

What is it and what causes it?

Primary amebic meningoencephalitis is a central nervous system disease caused by the ameba Naegleria fowleri. The parasitic ameba loves the heat and grows at temperatures up to 115 degrees Fahrenheit. Naegleria fowleri is found in warm freshwater lakes, rivers and streams, geothermal water such as hot springs and poorly maintained or insufficiently chlorinated swimming pools. The ameba does not grow in the ocean or other saltwater habitats.

The ameba infects people when it enters through the nose. From there, it travels to the brain and causes primary amebic meningoencephalitis. Symptoms usually resemble bacterial meningitis. Early infection stages typically start up to nine days and can include headaches, fever, nausea or vomiting. Symptoms in later stages include stiff neck, seizures, coma, hallucinations and altered mental status. People normally die five days after experiencing symptoms, but can die up to 18 days after symptoms begin.

Does this affect drinking water in or around Arlington?

No. Arlington drinking water is still safe for consumption, according to the city’s press release sent Monday afternoon. Even if it were affected, Naegleria fowleri cannot survive in stomach acid, making it impossible to get sick after drinking water with the ameba, according to the Louisiana Department of Health.

Cases reported in the U.S. have been associated with people using untreated water to rinse out noses, dipping their heads into bathrubs or using water from drinking water systems for slip-n-slides or swimming.

Arlington city government announced Monday they have closed all splash pads until the end of the year. Inspections of the device at Misenhimer Park that sequesters the facility’s water system from the city’s distribution system passed an annual inspection in April and again on Sept. 7.

Records from Misenhimer Park and the Beacon Recreation Center suggest that city parks and recreation workers did not consistently record and, in some cases, conduct water quality testing before opening, a process that includes checking chlorination levels. For example, the logs at Misenhimer Park did not include readings for two of the three days the child visited in late August and early September. The splash pad’s readings documented the day after the child’s visit showed that chlorination levels had fallen below minimum requirement.

Why is the disease so deadly?

To be clear, the disease is extremely rare. However, it progresses so quickly that patients are not often diagnosed until after they have died, according to the CDC. Detecting a case requires specific laboratory tests that are not always readily available.

Only four U.S. residents have survived an infection: one in 1978, two children in 2013 and a 16-year-old boy in 2013. Three children were treated using the drug miltefosine and, in some cases, by lowering the body’s temperature. Two of the three children made full neurological recoveries, according to the CDC.

What can I do to prevent myself from becoming infected?

The best way to prevent infection is to avoid swimming or water-related activities in warm fresh water, according to the CDC. Swimmers can also protect themselves by holding their noses shut or keeping their heads above water when in fresh water, or avoid streams altogether when water is at a higher temperature. Avoid digging in or stirring up sediment in shallow areas. Additionally, people should avoid immersing their heads in hot springs.

Catching the disease after using tap water is even more rare than becoming infected from a freshwater stream. However, people who rinse their noses should use boiled, distilled or sterile water for their routine. People unable to boil or buy sterilized water can also use a filter. The filter’s label should read NSF 53 or NSF 58 or mention “cyst removal” or “cyst reduction.” Filters with pore sizes of 1 micron or smaller can also be effective at removing the ameba. Water for nasal cleansing can also be treated with chlorine.