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November 2013, Volume 63, Issue 11

Student's Corner

Naegleria Fowleri — the brain-eating amoeba

Ramsha Zaheer  ( 5th Year Student, Dow Medical College, Karachi. )
Mishaal Bhurgri  ( 5th Year Student, Ziauddin Medical University, Karachi. )

Madam, with the temperatures soaring again, the incidence of Naegleria Fowleri is also on the rise. The first case of this year was a 14-year-old boy who was brought in on 10th May and passed away on 16th May 2013.1
In a statement issued a week later, the Karachi Water and Sewerage Board (KWSB) said that of the 110 samples collected from throughout the city\\\'s water supply and tested in the Naegleria monitoring laboratory, 30 reported the chlorine levels were not as per standard.2 It is therefore safe to assume that this is not the last we will hear of the brain-eating amoeba.
Naegleria Fowleri an amoeba commonly found in warm, fresh water, and enters the human body nasally, typically infecting people while swimming3 or more commonly in our set-up, during deep nasal cleansing while performing wudu.
Infection by N. Fowleri leads to primary amoebic meningioencephalitis (PAM) causing destruction of the brain tissue. Symptoms of PAM start about 5 days (range 1 to 7 days) after infection and mimic those of bacterial meningitis. Headache, fever, nausea, and vomiting are some of the initial symptoms. Later symptoms can include stiff neck, confusion, lack of attention to people and surroundings, loss of balance, seizures, and hallucinations. After the start of symptoms, the disease progresses rapidly and usually causes death within about 5 days (range 1 to 12 days).3
Currently, amphotericin B is the agent of choice for the treatment of PAM. However, it is a toxic antibiotic and can cause adverse effects on other organs. Studies are being conducted to check the efficacy of other drugs, including chlorpromazine4 and corifungin,5 which have yielded promising results so far.
The current dilemma however is differentiating PAM from patients presenting with bacterial meningitis. Cerebrospinal fluid (CSF) analysis in both cases are similar and with time being of the essence while treating PAM, awaiting results of other tests like immunohistochemistry and polymerase chain reaction (PCR) are out of the question. It would be prudent therefore, to take a thorough history from the patient, including recent water-based activities and details of performance of wudu. If a history is suggestive of PAM, a simpler method for diagnosis would be to visualise the motile amoeba in a fresh, non-refrigerated sample of CSF under a microscope or stain with Giemsa-Wright stain or the modified trichrome stain.
However since prevention is better than cure all patients should be counseled to use water that has been previously boiled for 1 minute and left to cool or filtered water while making a solution for irrigating, flushing, or rinsing their sinuses.3


1. Baloch S. \\\'Brain eating amoeba\\\' claims life of 14-year-old in Karachi. Beta Spider. DAWN May 17, 2013. (Online) (Cited 2013 June 14). Available from URL:
2. Brain-eating amoeba: Water samples show chlorine below required level. Dawn May 22, 2013. (Online) (Cited 2013 June 14). Available from URL:
3. Centres for Disease Control and Prevention. Naegleria fowleri - Primary Amebic Meningoencephalitis (PAM). (Online) (Cited 2013 June 14). Available from URL: naegleria/general.html.
4. Kim JH, Jung SY, Lee YJ, Song KJ, Kwon D, Kim K, et al. Effect of Therapeutic Chemical Agents In Vitro and on Experimental Meningoencephalitis Due to Naegleria fowleri. Antimicrob Agents Chemother 2008; 52: 4010-6.
5. Debnath A, Tunac JB, Galindo-Gómez S, Silva-Olivares A, Shibayama M, McKerrow JH. Experimental Therapeutics: Corifungin, a New Drug Lead against Naegleria, Identified from a High-Throughput Screen. Antimicrob Agents Chemother  2012; 56: 5450-7.

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