Residents of two Queensland towns are being urged to avoid diving into lakes or squirting water up their noses.
A parasite capable of destroying brain tissue has been detected in South West Queensland town water supplies, but health experts stress the risk to the community is extremely low.
Queensland Health public health and infectious diseases physician Dr Candice Holland has urged people not to panic following the discovery of Naegleria fowleri in Murweh Shire’s water supply.
“Many people are exposed to this organism, but only a very tiny few of those go on to have infection,” she said.
If N. fowleri reaches the brain, it can cause the rare infection primary amoebic meningoencephalitis, which is usually fatal even after treatment, according to Queensland Health.
Dr Holland said local GPs may be seeing patients who are concerned they’ve been exposed to the organism and are presenting with “weird and wonderful neurological symptoms” or common symptoms such as headaches.
However, she said it was important to reassure patients that the amoeba was widespread in the environment – including in tropical and subtropical regions of Australia – but infection was rare.
Dr Holland said people could be exposed to the organism when diving into warm, stagnant freshwater lakes and through bore water on properties.
“But despite that, and it being known to be present in the environment in Queensland, there’s only been very few people that actually go on to have the infection.
“The detections that we had were back in May, so we did a look back at the data for those areas where the detections were, and there’s no evidence that we’ve had cases presenting with meningoencephalitis with no cause found.
“So that’s reassuring from that perspective, that we haven’t missed any cases from this exposure.”
Dr Holland said the disease was rapidly progressive and usually presented within about five days of exposure.
The disease presents as per other causes of meningoencephalitis, starting with headache, fever, nausea and vomiting, then neck stiffness followed by encephalitis, with confusion, seizures and reduced level of consciousness.
“People would largely not be presenting to GPs for assistance. They’ll be presenting to hospital because they’ll be quite unwell,” Dr Holland said.
“The clinicians in the area are aware of these detections. They would know to test specifically for this organism if somebody did present with those clinical features.”
Dr Holland said there have been five confirmed cases and one probable case of primary amoebic meningoencephalitis in Queensland since 2000 – all of which were fatal. As the disease is so rare, detection and diagnosis can be slow, she said.
“People progress very quickly, and because it’s not in the forefront of clinicians’ minds to think about this as a diagnosis, by the time they get diagnosed, they might have met a fatal outcome, whereas if people are thinking about it and could test and treat early, you would hope that treatment might be successful.”
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Dr Holland said serological surveillance in some populations had shown that healthy individuals have had an immune response to N. fowleri.
“Because it’s a rare disease, it’s not understood why some people get the infection and others don’t. Part of it is to do with the concentration of the organism and the mechanism by which it enters through the nose and up into the brain, but it’s not known why those few got infected, but everyone else was okay.”
Dr Holland said N. fowleri infection is diagnosed via a lumbar puncture to collect a CSF sample, and a PCR is also done in Queensland.
The disease is usually treated with a combination of anti-fungal and anti-bacterial treatments given both intravenously and intrathecally – a combination that has successfully saved patients in the US, Dr Holland said.
“It’s a rare disease, so we don’t have an excellent evidence base to say this is the appropriate treatment, but … that’s been used to successfully treat patients in the past that have recovered.”
Dr Holland said N. fowleri was detected as an incidental finding during Queensland Health and University of Queensland testing for legionella.
According to Queensland Health, Naegleria is an amoeba found naturally in untreated fresh water and soil, particularly in warm, stagnant water between 25C and 40C, such as lakes and hot springs. N. fowleri is the only species known to cause disease in humans.
This is the first known confirmation of N. fowleri in Charleville and Augathella water supplies, Murweh Shire Council said.
The amoeba can’t be transmitted to people by drinking water, so it isn’t necessary to boil drinking water, Murweh Shire Council said. However, infection can occur when jumping, diving or falling into water, through nasal irrigation, when showering or when playing with hoses, sprinklers, water toys or slip and slides.
So for children, drinking water from the school bubblers is safe, but squirting water from the bubblers is not.
“If you are concerned for your child using a drinking water fountain, the use of a drink bottle filled with tap water is a safe alternative option,” Queensland Health said.
Murweh Shire Council is advising residents and visitors to Charleville and Augathella to take the following precautions:
- Do not allow water to go up your nose when bathing, showering or washing your face
- Supervise children when bathing, showering and washing their faces to prevent water from going up their nose
- Don’t allow children to play unsupervised with hoses or sprinklers and teach them not to squirt water up their nose
- Don’t put your head under water when bathing or swimming in pools filled with town water that has not been adequately chlorinated
- Avoid slip-n-slides and other activities where it is difficult to prevent water from going up the nose
- Avoid using the water for any form of nasal irrigation or nasal lavage.
For more information, contact the Darling Downs Public Health Unit on 07 4699 8240 or call 13 HEALTH – 13 43 25 84.
