Naegleria fowleri, often called the “brain-eating amoeba,” can cause alarm due to its severe infections. While the outcomes are devastating, cases are exceptionally rare. This article provides essential information about Naegleria fowleri to help parents understand the risks and implement protective measures.
Understanding Naegleria Fowleri
Naegleria fowleri is a single-celled organism that naturally exists in warm freshwater environments, including lakes, rivers, ponds, and hot springs. It can also be found in soil and, rarely, in poorly maintained swimming pools or untreated tap water. The amoeba cannot survive in saltwater.
Infection occurs when water containing Naegleria fowleri enters the body through the nose, typically during swimming, diving, or water sports. From the nasal passages, the amoeba travels to the brain, causing primary amebic meningoencephalitis (PAM), a severe and nearly always fatal brain infection. Infection cannot occur from swallowing contaminated water or through person-to-person contact. While extremely rare, with fewer than 10 cases reported annually in the United States, PAM is almost always fatal. Between 1962 and 2024, there were 167 reported cases in the U.S., with only four survivors.
Recognizing the Symptoms
Primary Amebic Meningoencephalitis (PAM) symptoms often resemble bacterial meningitis. Early signs include a severe headache, fever, nausea, and vomiting. These symptoms typically appear within 1 to 9 days after exposure to the amoeba, with a median onset around 5 days.
As PAM progresses, the disease rapidly worsens. Symptoms quickly escalate to include a stiff neck, confusion, loss of balance, seizures, and hallucinations. The disease progresses aggressively, leading to coma and usually death within 1 to 18 days after symptoms begin, with a median of about 5 days.
Diagnosis, Treatment, and Outlook
Diagnosing PAM is challenging because its early symptoms closely resemble common forms of meningitis, often leading to delays in diagnosis. Specialized laboratory tests are required to detect Naegleria fowleri in cerebrospinal fluid (CSF), brain tissue, or other samples. These tests are available in a limited number of laboratories across the United States.
Treatment for PAM involves a combination of medications, including miltefosine, amphotericin B, azithromycin, fluconazole, rifampin, and dexamethasone. Despite aggressive treatment, PAM has an exceptionally high mortality rate, exceeding 97%. Early diagnosis and prompt, aggressive administration of these medications are crucial for the few individuals who have survived.
Protecting Your Children
To protect children from Naegleria fowleri infection, employ prevention strategies, particularly during warmer months when the amoeba is more prevalent. Avoid swimming, diving, or jumping into warm freshwater bodies, especially during periods of high water temperature and low water levels. When engaging in water activities in such environments, children should hold their noses shut, use nose clips, or keep their heads above the water to prevent water from entering the nasal passages. Parents should also caution children against stirring up sediment in shallow, warm freshwater, as Naegleria fowleri is more likely to reside in these disturbed areas.
For nasal rinsing practices, such as using neti pots, only use distilled, sterile, or previously boiled and cooled tap water. Proper disinfection and maintenance of swimming pools and hot tubs are essential, ensuring adequate chlorine levels and pH balance, as Naegleria fowleri is killed by proper chlorination. When showering or bathing with untreated private well water or from poorly disinfected municipal systems, avoid allowing water to enter the nose. If a child experiences a sudden onset of severe headache, fever, nausea, or vomiting after recent freshwater exposure, seek immediate emergency medical care and inform medical professionals about the potential water exposure.