Primary amoebic meningoencephalitis (PAM)
What is primary amoebic meningoencephalitis?
Primary amoebic meningoencephalitis (PAM), also called amoebic meningitis, is a serious illness. It causes inflammation of the brain.
An amoeba (Naegleria fowleri) causes PAM. The amoebas live in warm, fresh water and soil.
Infection often happens during water-based recreational activities.
Although many people have contact with the amoebas, only a small number of people develop PAM.
What are the symptoms of primary amoebic meningoencephalitis?
The symptoms of PAM are the same symptoms as those for meningitis.
The first symptoms are:
- headache
- high fever
- nausea (feeling sick)
- vomiting
These symptoms start about 5 days after infection.
Later symptoms are:
- neck stiffness
- confusion
- loss of balance
- seizures (fits)
- hallucinations
Early diagnosis and treatment may help improve survival. But unfortunately, most people who get PAM usually die.
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What causes primary amoebic meningoencephalitis?
The amoeba Naegleria fowleri causes PAM.
The amoebas grow in untreated water. They grow best in warm water, between 25°C and 40°C.
You can find the amoebas in:
- still water, such as lakes and rivers
- hot bore water
- long surface pipes
- water hoses
- spas
It's very rare to get PAM from a swimming pool.
PAM infection happens when water with Naegleria fowleri travels up your nose. This might happen when you:
- jump into water
- dive into water
- fall into water
The amoebas make their way to the brain. In the brain they destroy brain tissue and cause inflammation.
Even if water with the amoebas goes up your nose, your chance of getting PAM is still very small.
You can’t get PAM from:
- drinking water with the amoebas
- another person
When should I see my doctor?
The symptoms of PAM are common for many conditions. It’s important to see your doctor for a diagnosis.
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How is primary amoebic meningoencephalitis diagnosed?
A doctor must make your diagnosis.
See a doctor or go to a hospital emergency room urgently if you think anyone has PAM.
Make sure you tell the doctor that you believe water may have gone up your nose.
While PAM infection can happen at any age, children and young adults are more likely to get the disease.
How is primary amoebic meningoencephalitis treated?
There are no standard treatments for the treatment of PAM.
Combination therapy using medicines to treat parasites offers the most promise.
Can primary amoebic meningoencephalitis be prevented?
To stop PAM infection:
- don’t jump or dive into warm fresh water or thermal pools
- keep your head above water in spas, thermal pools, and warm fresh water
- empty and clean small wading pools — let them dry in the sun after use
- make sure swimming pools and spas are chlorinated and well maintained
- flush still water from hoses before letting children play with them
If you are using unchlorinated water:
- don’t let water to go up your nose when showering or washing your face
- watch children playing with hoses or sprinklers
- teach children not to squirt water up their nose
On remote properties, filtering and disinfecting the water used for washing and playing can prevent PAM.
What are the complications of primary amoebic meningoencephalitis?
PAM is a very rare disease. Unfortunately, PAM usually leads to death.
Resources and support
You can learn more about PAM through these state and territory health departments:
You can also call the healthdirect helpline on 1800 022 222. A registered nurse is available 24 hours a day, 7 days a week.
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Last reviewed: July 2022
