Health Alert for Swimmers

Published on Thursday, 12 December 2019 at 10:24:37 AM

This alert is for December 2019 through to March 2020.

The Shire of Gingin Environmental Health Service regularly tests the Moore River at Guilderton as part of the State Health Department’s Recreational Water Sampling Program.

The organism, Thermophilic Naegleria, has been identified in river water samples taken in the past in the Moore River. The Shire advises bathers who frequent or visit this area for recreational swimming to take the following precautions to avoid this organism.


Thermophilic Naegleria refers to a group of amoebae which includes Naegleria fowleri, the organism that causes the waterborne disease amoebic meningoencephalitis.

Thermophilic Naegleria refers to those microorganisms that are tolerant to 42°C. The microorganism that causes amoebic meningitis, Naegleria fowleri, is the most severe.

This organism has not been identified in any recreational water bodies within the Shire of Gingin to date. However, the Thermophilic Naegleria organism has been detected and is considered to be the pre-cursor to possible Naegleria fowleri.


People are urged to take precautions to avoid potentially fatal amoebic meningitis from 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.


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 results in higher water temperatures. You cannot get infected by swallowing water containing Naegleria.


  • Keep your head above the water in thermal pools and warm fresh water bodies such as the Moore River
  • 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 thermal pools and warm fresh water bodies.

This information is provided for the safety and well being of you and your families.


The Shire carries out weekly water sampling of the Moore River (and other sites around the Shire) during the warm summer months as part of the Department of Health’s state-wide water monitoring program. To date, the Shire HAS NEVER detected Naegleria fowleri in the Moore River.

Should Naegleria fowleri be detected then the Department and the Shire will implement immediate procedures to warn the public of the potential dangers that the organism may cause and how to avoid contracting it.

The last reported case of Naegleria fowleri occurred in WA in 1985. That is not cause however, for complacency and all swimmers should take care when swimming in any recreational bodies of water during the summer months. Avoiding inhaling any water via the nasal passage is of the utmost importance.


Contact the Shire's Health Department on (08) 9575 5100.

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