Recent test results have shown Naegleria fowleri, which causes amoebic meningitis, is not present at Collie's Black Diamond swimming pool in south-west Western Australia.

However, shire executive manager of development services Keith Williams told WA Drive that other strains of Naegleria were present.

"We are taking a very precautionary approach," he said. "We have a duty of care.

"Although there is a low probability of infection, we want to make sure that people are safe. It is an invariably fatal disease."

Testing regime in place

Black Diamond pool is an abandoned coal mine about 5km west of Collie that has been a popular recreation spot since the 1950s.

Collie Shire has been randomly testing the pool waters for the past six to eight weeks.

Regular sampling began because of a number of factors such as high use, low rainfall and warmer temperatures.

Mr Williams said there had been community complaints about sickness after swimming at the pool, but no cases were found to be have been caused by the water.

"There has also been illegal camping which could have affected water quality," he said.

A water temperature higher than 24 degrees is the threshold for Naegleria to thrive.

Cautious approach to a remote likelihood

The probability of contracting amoebic meningitis is extremely low, Mr Williams stressed.

The organism can only infect people via the nasal passages and sinuses, not through cuts and scratches. Amoebic meningitis facts It is a very rare but deadly disease.

Just three cases have been reported in WA with the last being in 1985.

Symptoms are the same as with bacterial meningitis: headache, fever, nausea, vomiting and neck stiffness.

Symptoms start within 24 to 48 hours of swimming in a fresh, warm, natural water source.

Amoebae enter through the nose and travel to the brain, causing inflammation and eventual destruction of the brain lining.

Most of the victims are children and young adults.

"People who have been swimming at Black Diamond over Christmas and New Year are at no risk," he said.

Mr Williams said Collie Shire would continue testing on a regular basis and, while the water temperatures were high, would restrict access.

"We definitely don't want swimming in Black Diamond while the water temperatures are high and while the amoebae are there," he said.

"If you do enter the water, don't put your head under. Don't jump or dive into the water because it is more likely (amoebae) would enter your nose.

"While fowleri specifically is not present, conditions are right for it."