Push to explore potential link between Motor Neurone Disease and blue-green algae
New South Wales man Tim Trembath realised something was wrong when he felt a strange weakness in one of his biceps during a chin-up competition with his son.
Mr Trembath is now in a motorised wheelchair after being diagnosed with Motor Neurone Disease (MND), a condition that has doubled in prevalence in Australia over the past 30 years — an increase neuroscientists say cannot be explained by an ageing population or advances in diagnoses alone.
Ten per cent of cases are inherited, but for the other 90 per cent there is no known cause, and that is a mystery Mr Trembath, who falls into the latter category, would like to see solved.
“It’s just too many people getting this type of disease,” he said.
“I had the doctor say to me, ‘You’ve got motor neurone disease’, and he said that it was life threatening, and I was trying to comprehend that.
“Losing the function of your limbs was just horrible, you know, it was a real kick in the guts.”
Algae explored as potential factor in spike
Motor Neurone Disease (MND), causes progressive muscle weakness and eventually complete paralysis.
Some scientists believe the reason behind the big increase in these sporadic cases could be environmental, and they are investigating a range of potential factors, including pesticides and heavy metals.
One theory is that a toxin produced by blue-green algae called Beta-N-Methylamino-L-Alanine (BMAA) might be a trigger for the disease.
Rachael Dunlop, a senior research fellow with Brain Chemistry Labs in Wyoming in the United States, said international research shows a correlation.
“There are studies now showing that people that live beside lakes and rivers where there are frequent algal blooms, cyanobacterial blooms, have an increased risk of contracting motor neurone disease,” she said.
“That doesn’t mean we have evidence for a direct cause — and I want to emphasise that, just like people that smoke don’t necessarily get lung cancer.
“This is probably a risk factor.”
Associate Professor Ken Rogers, a cell biologist from the school of Life Sciences at the University of Technology Sydney, says just because the BMAA toxin is a risk factor, does not mean it is a risk factor for everyone.
“I think that like any toxin you probably need some susceptibility to it,” he said.
“A lot of people live near lakes with algal blooms, but not everyone gets MND.”
Dr Rogers said Australia needs to try and replicate overseas research by investigating whether there are clusters of MND near blue-green algae.
“There are definitely hotspots of MND around the world,” he said.
“It’s been identified in France and the US, and we believe there could be one in New South Wales.”
The prevalence of MND in Griffith, in the New South Wales Riverina region, is estimated to be about five times the national average.
The town is close to Lake Wyangan, which is prone to blue-green algal blooms.
The area has become a focus for scientists looking into whether the neurotoxin could be playing a role in triggering MND.
Calls for more research
The head of the Motor Neurone Disease Centre at Macquarie University, neurologist Dominic Rowe, said it is an important issue to investigate.
“We should do everything possible to try and find out whether this is a contributing factor to Motor Neurone Disease,” he said.
“It’s just not good enough to go, ‘Oh well, I don’t know.'”
One in every 11,000 Australians is estimated to have MND, but Dr Rowe says in some places that figure is much higher.
“This disease robs you of your ability to walk, to talk, to write, to breathe, to live,” he said.
“It’s a horrifying disease and if we can understand BMAA and how it’s involved in Motor Neurone Disease, this will instruct us as to the mechanism of the disease.
“Ideally it will help us prevent Motor Neurone Disease.
“I’d give my left arm to prevent one case of Motor Neurone Disease.”
Macquarie University professor Gilles Guillemin is one of the country’s top experts on the BMAA toxin.
But his research trying to identify potential MND clusters near blue-green algal blooms has stalled due to lack of funding.
“We’re trying to see if we can find a correlation between people living around contaminated water and people developing motor neurone disease,” he said.
Blue-green algae toxin one of many MND theories
Lake Cargelligo, in the NSW central-west, has a population of about 1,500, and is another area where there are an unusually high number of people who have developed MND.
Local GP Khaled Bardawil says he’s been shocked by the number of people presenting with MND.
“I’ve been in this town for nearly 13 years and before coming here I only saw maybe one or two cases in my career,” he said.
“But here, in Lake Cargelligo, I know or I have treated four patients.
“For a small town like Lake Cargelligo, to have four maybe five cases, it’s too much.”
Mr Trembath lives in Lake Cargelligo, and he wants more funding for scientists to get to the bottom of whether environmental triggers are playing a role in MND.
“As far as blue-green algae and my disease, I hope they find a connection because I think if they find a connection they’ll find a cure,” he said.
“If they disprove it, they can spend their resources looking somewhere else.”
In a statement, a spokesperson for NSW Health said there could be significant variations in the rates of MND between places and over time.
“There are many theories about the causes of MND,” the spokesperson said.
“One of those theories is that it is caused by a toxin produced by blue-green algae — however, there has been no definitive evidence to support this theory.”