Suspected second outbreak of deadly amoeba rings alarm bells for swimming in freshwater systems this summer

A second outbreak of a brain-eating amoeba is suspected at another popular swimming spot in the South West, with authorities warning about the risks of cooling off in dams, rivers and backyard wading pools this summer.

Evidence of the family to which deadly amoeba naegleria fowleri belongs was found in Drakesbrook Weir by the Shire of Waroona this week.

The same family of amoeba was also detected in Brunswick Pool by the Shire of Harvey last week.

The Waroona shire said the recent scorching weather has taken a toll on water quality and that they have posted signs around the area warning people against swimming in the weir.

Health Department managing scientist Richard Theobald said the free-living amoeba can be found naturally in any body of fresh warm water including lakes, rivers and poorly chlorinated swimming pools.

Mr Theobald warned against swimming in at-risk locations as the amoeba can cause a rare but fatal infection known as amoebic meningitis.

“The amoeba is happy in water where the temperature is lovely for you to swim, around 28 to 30 degrees Celsius,” he said.

“We advise as many people as possible, particularly during the summer months, to avoid swimming in natural bodies of fresh water.”

Mr Theobald said along with natural water systems, garden hoses and poorly chlorinated swimming pools posed a risk of infection, particularly children’s inflatable wading pools.

“If there is nice warm water in a pool with no chlorine but a little bit of dirt, you start to run the risk of amoeba, so that water should be emptied and then refilled regularly,” he said.

“Infection is very rare (but) the death rate is 99 per cent.”

He said swimmers could be infected when water was thrust up their nose, with children and young people who jump feet first into water more at risk.

“When infected, the amoeba travels to the brain and does what amoeba love to do: multiply and consume,” he said.

Mr Theobald said there had been only three known infections in the State since the 1980s but avoiding potential risk was still advised.

The Waroona shire is awaiting the results of tests to rule out the presence of the amoeba. It will post the results of the testing as soon as it becomes available.

For more information about amoebic meningitis and precautionary measures, visit healthywa.wa.gov.au.