The Waroona Dam has been cleared of hosting a brain eating amoeba after a shock discovery of a related bug.
The Shire of Waroona closed the dam — also known as Lake Navarino — earlier this month due to a positive result for the genus naegleria amoeba in the water.
Testing has since ruled out the specific Naegleria fowleri species which is commonly referred to as a brain-eating amoeba.
The specific kind of amoeba is known to cause primary amoebic meningoencephalitis, a rare but usually fatal disease which occurs when the amoeba travels through the nose and into the brain, according to the Federal Department of Health.
It was the first time the dam had returned a positive result for the species, something which was unexpected for Waroona shire president Mike Walmsley.
“The little weir has (tested positive) the last few years . . . but the Waroona Dam came as a little bit of a shock this time,” he said earlier this month.
The move comes less than a month after the Drakesbrook Weir was closed for more than a week in a separate incident of a possible Naegleria amoeba presence.
However, it was quickly found not to be the deadly Naegleria fowleri.
It was the third time in 2024 the weir had been closed due to the possibility of the deadly bug, but there is yet to be any confirmation of the dangerous amoeba.
