Naegleria fowleri infection facts
- Naegleria fowleri is an amoeba that lives predominately in warm freshwater.
- Naegleria fowleri is acquired by people when infected water is forcibly aspirated into the nose. This can occur through recreational swimming, diving, or during sports like water skiing.
- Once acquired, the amoeba travels into the brain, causing primary amoebic meningoencephalitis (PAM). In the popular press, Naegleria fowleri is sometimes called the
"brain-eating amoeba,"and meningoencephalitis is sometimes referred to as Naegleriasis.
- PAM is very rare, and there are only a few cases reported each year in the United States.
- People with PAM have a rapidly progressive illness with fever, headache, and stiff neck, and finally coma and death.
- Infection is diagnosed by examining spinal fluid under the microscope to identify the amoeba. Naegleria fowleri may also be grown in the laboratory, although this takes several days. Newer tests based on PCR technology have been developed but are not widely available.
- The treatment of choice is an intravenous drug called amphotericin B. Amphotericin B may also be instilled directly into the brain. Because treatment with amphotericin B alone usually fails, other drugs are often added. Miltefosine is a drug that has shown promise, and it is available through the Centers for Disease Control and Prevention. Treatment should be initiated as rapidly as possible, and immediate consultation with an infectious-diseases expert is highly recommended.
- More than 99% of cases of PAM are fatal despite treatment.
What causes a Naegleria fowleri infection?
N. fowleri infection is a water-borne disease. Exposure occurs when people come into contact with warm freshwater usually through swimming, diving, water skiing, or other recreational activity. Although contact with infected water is common in the United States, symptomatic disease caused by N. fowleri is rare.
The danger of serious infection comes when water containing Naegleria fowleri is forced into the nose. The amoeba then migrates through the olfactory nerves and enters the brain. The initial exposure can occur when diving or inadvertently aspirating water during swimming. Rarely, underchlorinated swimming pools have been implicated in transmission. Because Naegleria fowleri can be present in untreated well water, there is a small but real chance of transmission to young children during bathing.Naegleria fowleri has also caused disease in adults who inject water into the nose as part of ritual ablutions related to religious practices or as an irrigating solution for sinus passages.
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CAUTION for SWIMMERS