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Amoebic meningitis

In New Zealand amoebic meningitis first came into prominence in 1968, when four young people died from Amoebic meningitis after diving in Okauia hot thermal pools in Matamata.  To date, all 10 cases seen in New Zealand since then, have also occurred in springs in the North Island, along the course of the Waikato River, between Taupo and Matamata.

Amoebic Meningitis is extremely rare, with around 300 cases reported worldwide (and three survivors) since the mid 60’s.  There are probably cases and survivors that are never reported in medical journals.  Amoebic meningitis is primarily thermophilic, and is found in fresh water ponds, lakes and rivers when temperartures are high, or is found in naturally occurring, inadequate treated (cholorinated) hot thermal water.

Given the number of people who put their heads underwater in hot pools, the likelihood of coming down with amoebic meningitis is highly remote.  Most New Zealanders adults have a high awareness of amoebic meningitis, and tend not to put their heads under water.  But children will be children. The risk, while remote, is there, particularly in untreated hot pools.   

There are many different types of Naegleria which can cause meningitis, which are everywhere there is naturally arising thermal hot water, but there are others organisms that are also implicated elsewhere in the world.  Naegleria fowleri (N. fowleri) and N lovaniensis appear to be the organisms so far implicated in New Zealand, although N australiensis and N. gruberi have also been identified. 

Amoeba will be much higher in thermal pools fed directly from untreated geothermal ground water, so if you go into hot pools out in the bush, don’t put your head under water.  If you get any water up your nose, blow it out straight away.

Amoebic meningitic, has an incubation time of 3 – 10 days according to New Zealand articles, and 1-2 days according to CDC .  Meningitis is caused when the amoebic trophozoite is forced up the nose, and directly enters the cerebral spinal fluid via nerves from the nose.  Symptoms can progress rapidly, and sometimes include:

• severe and persistent headache
• no appetite
• sore throat
• nausea and vomiting
• seizures
• high fever and sleepiness.

Of the ten New Zeland cases, 9 were children who presented with fever, and the one adult had no classical symptoms. 

The symptoms can progress to stupor, coma and death within 2-3 days. But be aware that classic symptoms can be absent. 

Treatment is centred around using intravenous drugs like amphotericin B with tetracycline, rifampicin, floconazole, ordinazole, itraconazole.

The New Zealand Medical Journal has two interesting articles on Amoebic meningitis.  The first is December 12, 2003 and the second is February 20, 2004.

Other organisms are implicated in Amoebic meningitis. An American medical article describes some other organisms here. here

A review from Thailand is also interestings: Here is a list of New Zealand thermal springs:

There is a book called “Hot Springs of New Zealand" here.

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