Amoebic meningitis (Naegleria fowleri) – warning for households
People are urged to take precautions to avoid potentially fatal amoebic meningitis from Naegleria fowleri.
What is Naegleria fowleri?
Naegleria fowleri is an amoeba (microorganism), commonly found in unchlorinated warm fresh water and soil. Any water supply that seasonally exceeds 30°C or continually exceeds 25°C may be a risk. This includes lakes, rivers, dams, bores, tanks, pipelines, natural hot waters/springs and spa and swimming pools that are poorly maintained, under-chlorinated or unchlorinated. Naegleria cannot survive in water that is clean, cool and adequately chlorinated.
How do you get infected?
A very rare but often fatal infection (amoebic meningitis or meningoencephalitis) can occur if contaminated water goes up into the nose. This may occur when people swim, dive or fall into warm unchlorinated water containing Naegleria, or when children play under sprinklers or with hoses using this water, or when infected water is inhaled to cleanse the nasal passages. Children and young adults appear to be more susceptible to infections than adults. Infections usually occur when it is hot for prolonged periods of time, which result in higher water temperatures. You cannot get infected by swallowing water containing Naegleria.
How is Naegleria infection prevented?
To prevent infection, household water supplies should be disinfected by continuously maintaining a free chlorine residual concentration of 0.5 milligrams per litre or higher. Take the following precautions:
- flush stagnant water from hoses before allowing children to play with hoses or sprinklers
- if you are using unchlorinated water:
- don't allow water to go up your nose when bathing, showering or washing your face
- supervise children playing with hoses or sprinklers and teach them to not squirt water up their nose
- potentially contaminated water should not be used for any form of nasal irrigation or nasal lavage including Neti (an Ayurvedic practice of nasal cleansing).
For recreational waters:
- ensure swimming pools and spas are adequately chlorinated and well maintained
- empty and clean small collapsible wading pools and let them dry in the sun after each use
- keep your head above water in spas, thermal pools and warm fresh water bodies
- avoid jumping or diving into bodies of warm fresh water or thermal pools (or any actions where water is forced into the nose at pressure)
- do not submerge your head when in spas, thermal pools and warm fresh water bodies.
Households with a private water supply
Households with a private water supply should be familiar with the quality of their drinking water. Private supplies may include rainwater, groundwater (from bores or springs), surface water (from a dam or stream) or carted water. Water used for household purposes such as drinking, food preparation and personal hygiene (including cleaning teeth/oral hygiene and bathing) should meet water quality guidelines in order to protect you and your family’s health. You do not need to test for Naegleria fowleri directly. Any warm unchlorinated fresh water could contain Naegleria.
NSW Health recommends that groundwater and surface water is not used for drinking, cooking and personal hygiene (including cleaning teeth and bathing) without testing and appropriate treatment including disinfection. This can be done by testing the microbiological, chemical and radiological quality of the water and disinfecting with chlorine.
Rainwater tanks are widely used as a source of drinking water in rural Australia. A properly maintained rainwater tank can provide good quality drinking water. Adequate disinfection can protect against harmful microorganisms.
For more information
Contact your local Public Health Unit on 1300 066 055 and refer to: