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"Brain-Eating Amoeba" Cases Reported in More States, Officials Warn—How to Stay Safe

A new case report says the dangerous microorganism is on the move due to climate change.

The COVID pandemic made us more aware that unexpected health risks are a constantly evolving threat. Whether it's a food-based outbreak like Salmonella or a particularly dangerous version of the seasonal flu, knowing about any new issues can be essential to help prepare yourself. This is especially true if the cause in question is relatively new to a specific area or population. And now, officials warn that more cases of a potentially fatal "brain-eating amoeba" have been reported in more states. Read on to see how you can stay safe from the microscopic threat.

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Health officials warn that a dangerous "brain-eating" microbe is now spreading to new areas.

A scientist completing a study in a lab looking into a microscope while wearing full protective gear

People who live in normally cooler climates may have a looming new health threat to worry about. In a case report published in the Ohio Journal of Public Health on May 16, officials from the Ohio Public Health Association warn that the potentially fatal "brain-eating" amoeba Naegleria fowleri was beginning to expand its habitat to the north as average temperatures continue to rise.

"Increased incidence of N. fowleri in northern climates is but one of many ways climate change threatens human health and merits novel education of health care providers," the authors wrote in the case report.

The infamous single-celled organism is found in fresh water and soil in warmer climates in places such as lakes, rivers, and hot springs, according to the Centers for Disease Control and Prevention (CDC). And even though drinking water infected with the amoeba won't cause harm, it can cause a serious disease known as primary amebic meningoencephalitis (PAM) if it enters the body through the nose—often while swimming.

Reported cases of PAM have begun spreading to more northern states over the past decade.

Family Splashing on a Lake
Robert Kneschke/Shutterstock

The CDC reports that PAM remains a relatively rare infection, with an average of just three reported cases in the U.S. each year and a total of 157 infections from 1962 through 2022. However, the disease is nearly always fatal, with just four reported domestic cases surviving the illness.

To date, health officials have reported the most PAM cases in southern states, according to CDC data. Florida and Texas have the most, with 37 and 39 illnesses since 1962, respectively, followed by 10 in California; nine in Arizona; eight in South Carolina; seven each in Virginia, Oklahoma, and North Carolina; six in Arkansas; five in Georgia; and four in Louisiana. But in its case report, Ohio health officials point out that cases have been reported in more northern states since 2010, including two each in Kansas and Minnesota and one in Indiana.

"Ohio public health professionals should take note of the incidence of N. fowleri infections in northern states including Indiana, Iowa, and Minnesota, as well as common vacation destinations for Ohioans where N. fowleri infection has been reported, such as Virginia, North Carolina, South Carolina, Georgia, and Florida," the officials warned in their report.

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Symptoms can show up one to 12 days after infection with the amoeba.

woman feeling headache from flu and cold holding a glass of water, health problems treatment

Because of their relative rarity, Naegleria fowleri infections are often misdiagnosed as bacterial meningitis at first. This is also because the disease carries similar symptoms, which usually begin one to 12 days after infection with nausea, vomiting, fever, and a severe frontal headache, according to the CDC.

The disease then progresses to include a stiff neck and more serious symptoms, such as seizures, hallucinations, altered mental status, and coma. Unfortunately, the fast pace of the infection usually means that patients aren't even diagnosed with PAM until after they've died, which generally occurs one to 18 days after symptoms first appear.

N. fowleri infections are rare, but early detection can be crucial to recovery.

Patient sleeping in hospital bed.

According to the CDC, the risk of PAM is challenging to calculate because of how rare the disease is—especially given that so many people engage in activities that could potentially expose them yearly. "It is unknown why certain persons become infected with the amebae while millions of others exposed to warm recreational fresh waters, including those who were swimming with people who became infected, do not," the agency writes on its website. They add that even though testing has been done to see what concentrations of the amoeba in the water could be considered risky, there are currently no methods that public health officials could use to measure or enforce standards for safety.

However, Ohio health officials cite in their report that awareness of the microorganism can lead to earlier detection and diagnosis that can improve outcomes. "Combined with increased incidence in northern climates, untrained and unaware public health professionals and health care providers may exacerbate prolonged diagnostic periods and delay time-sensitive treatment in what is ultimately a quick decline for PAM patients," the report states.

Even though the disease is highly fatal, the CDC points out that most recent cases in which patients survived resulted from early detection and treatment. In 2013, a 12-year-old girl was diagnosed within 30 hours of the onset of her symptoms and treated with an experimental drug known as miltefosine and therapeutic hypothermia, in which the body is cooled to lower than normal temperatures. The agency notes that she "made a full neurologic recovery and returned to school."

The Ohio case report also outlines a recent case in which a woman in her 30s was brought into the hospital with suspected bacterial meningitis. After her spouse told a nurse she had been swimming in freshwater four days earlier and had submerged her head, her medical team contacted the CDC for treatment recommendations before beginning a course of miltefosine. The report says the woman recovered "with minimal neurological damage and was able to resume a high quality of life with her family" after two weeks.

Zachary Mack
Zach is a freelance writer specializing in beer, wine, food, spirits, and travel. He is based in Manhattan. Read more
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