Is there a link between motor neurone disease and blue-green algae? NSW expert calls for closer look
Sep 26 2021
A top neurologist has called on the New South Wales government to list motor neurone disease (MND) as a notifiable disease amid suspicions a cluster of diagnoses in the state could be linked to something in the environment.
Prof Dominic Rowe, a neurologist at Macquarie University, has treated 889 MND patients – many from the NSW irrigation town of Griffith – in the past decade.
Rowe is concerned the prevalence of cases in the region could be linked to something in the environment, with researchers investigating links to blue-green algae, pesticides and heavy metals.
But he says his team is limited in their research because MND is not listed as a notifiable disease – one that must be reported to authorities.
If MND were given notifiable disease status, researchers could access location data that would allow them to see where people with the disease live in relation to places like lakes and water bodies, Rowe said.
They have access to “observational” data from patients, but Rowe says this is “not comprehensive”.
“If we just close our eyes and continue holding people’s hands as they die, that’s not satisfactory at all,” he says.
MND is a progressive neurological disorder that leaves people unable to walk, speak, swallow and ultimately breathe.
In Australia, MND has increased in prevalence by around 250% over the past three decades, according to Rowe.
While 5-10% of cases are believed to be genetic, Rowe says he “strongly suspects” something in the environment is driving a rise in the remaining sporadic (non-genetic) cases.
The data from a notification listing would help researchers zero in on cases and scour the surrounding environment for clues about their cause, Rowe says.
He says if an environmental cause can be identified, prevention – and even a cure – may be possible, and that “we should move heaven and earth” to get there.
Not far from Griffith is a lake surrounded on two sides by picturesque farming land. It has become a focal point for researchers looking into high rates of MND in the region.
Michelle Vearing says her family visited Lake Wyangan “every other weekend” while growing up and the kids would spend hours swimming and water skiing in the water. The recreational area of Lake Wyangan is operated by the Griffith city council.
Vearing lost her grandfather and mother to a genetic form of MND and is now supporting her sister Tania Magoci as she battles the disease.
Vearing is a volunteer with the Griffith MND support group, which organises many of its activities through social media. Its Facebook page contain a mix of tributes to people who have died, requests for urine and blood donations for research trials, and fundraising sales of everything from hand-stitched quilts to a treasured rugby league jersey.
“Nearly everyone in town knows someone who has or has passed away from MND,” Vearing says.
Out of the 30 people in the area who have passed away from the disease over the past decade, many had strong connections to Lake Wyangan or other nearby bodies of water, Vearing says.
In recent years the lake has become prone to blooms of cyanobacteria, commonly known as blue-green algae, a natural feature in Australian waters and one experts say is thriving as the climate becomes hotter and drier.
So far the NSW government has rebuffed the proposal to list MND as a notifiable disease.
In June, the NSW health minister Brad Hazzard agreed to meet with representatives from the Macquarie University research team to discuss the proposal, but the meeting was postponed due to the state’s coronavirus outbreak.
In a statement, the NSW health department said MND did not meet criteria to be made notifiable, which included “the potential for outbreaks, a necessity for urgent public health response and preventability”.
Jan 2019: What Causes Algal Blooms and How We Can Stop Them
February 2019 – Griffith (New South Wales) – Blue Green Algae
We explore the link between NSW waterways and a toxin that might trigger MND.
Professor Dominic Rowe of Macquarie Neurology says, “From 1986 to 2016, there’s been a 250% increase in Motor Neurone Disease as a cause of death in Australia and that can only be environmental…”
Research overseas has linked the neurotoxin BMAA, a by-product of blue-green algae, to MND. This toxin was recently discovered in Lake Wyangan in NSW.
It’s also been found in a number of other drought-affected New South Wales waterways, including along the Darling River.
Professor Rowe says, “If we can understand what in the environment triggers Motor Neurone Disease, conceivably we could prevent [it] from even occurring.”
Tim Trembath, an MND sufferer, lives at Lake Cargelligo, which is 140-kilometers north of Griffith. He’s spent a lot of time at this lake, where there’s been an outbreak of blue-green algae.
Tim says, “Up until about 2010, the lake water was the water that was used for drinking and washing in the town.”
The disease has stripped Tim of his ability to ride his motorbike and he needs regular care. Two of his friends in the 1500-resident town have died from MND.
“Anyone who lives in this town has probably swum in the lake, and the lake has algal blooms in it nearly every summer.”
While it’s easy to assume there’s a link between these waterways and MND, Professor Rowe says, “It is highly unlikely that there’s going to be one specific environmental trigger, it’s likely to be a combination of factors.”
Toxin Linked to Motor Neuron Disease Found in Australian Algal Blooms.
Algal blooms in major Australian rivers are releasing a toxic chemical that may contribute to the development of motor neuron disease (MND).
My colleagues and I tested algae from waterways in New South Wales, and found that a neurotoxin called BMAA was present in 70% of samples, including those from crucial water sources such as the Darling and Murrumbidgee rivers.
This compound is well known overseas, and has been found in waterways in the United States, Europe, Asia, and the Middle East. But this is the first time it has been detected in Australia. Although its presence has been suspected, it was never specifically tested until now.
Two samples containing BMAA were collected from the Murrumbidgee River, which runs through the NSW Riverina, a hotspot for MND in Australia. Positive samples were also collected in Centennial Park and Botany wetlands in central Sydney, as well as Manly Dam on Sydney’s Northern Beaches.
In the past 30 years, Australian rivers have had the dubious honour of hosting some of the largest algal blooms in history. In 1991 a bloom stretched along more than 1,200km of the Darling River, prompting the New South Wales government to declare a state of emergency. The army was mobilised to provide aid to towns.
Since then, southeast Australia has had four large blooms, most recently in 2016. The future isn’t promising either. Rising water temperatures mean blooms are likely to increase in frequency and duration in the future.
Multiple state agencies monitor populations of types of bacteria in Australia, regularly testing water quality and issuing alerts when blooms are present. This testing is necessary because of the impressive number of toxins that cyanobacteria can produce, ranging from skin irritants to liver and neurological toxins. Most of these compounds are relatively fast-acting, meaning that their effects take hold rapidly after exposure.
The neurotoxic compound BMAA, however, is not currently part of regular testing, despite links between long-term exposure to algal blooms and the development of diseases such as MND. BMAA is known to be produced by a type of freshwater and marine bacteria, as well as some species of algae.
How BMAA affects our health
Research in America found that regular participation in water-based recreational activity resulted in a threefold increase in the risk of developing MND. Satellite mapping also revealed that lakes prone to algal blooms were often surrounded by clusters of MND patients.
Southwestern NSW has become a focus for MND researchers since 2014, due to the presence of a hotspot for MND cases around the Riverina. The town of Griffith has reported a prevalence of this disease that is nearly seven times higher than the national average of 8.7 cases per 100,000 people. Hotspots like these can help researchers identify environmental factors that contribute to diseases.
This is particularly important in MND, in which only 5-10% of patients have a family history. The other 90-95% of cases are sporadic, occurring without warning. It is possible that BMAA exposure, in association with genetic, or other environmental risk factors, contributes to the high incidence of MND in the Riverina.
BMAA also has a similar structure to the amino acids that make up the proteins in our body. We hypothesise that this contributes to its toxicity and ability to build up in animal tissue and in plants that are exposed to contaminated water.
Similar to mercury, BMAA can accumulate in the food chain, which means that people could be consuming relatively large amounts of it through their diet. A US animal study found that dietary exposure to BMAA resulted in the formation of plaques and protein tangles in the brain, which are hallmark features of neurodegeneration.
Research now needs to focus on tracking and monitoring algal blooms to detect the presence of BMAA, and determining how long it remains in the ecosystem after these blooms occur.
This can potentially help to reduce human exposure to BMAA. Although the factors that cause MND are many and varied, we hope this understanding could ultimately help to reduce the number of people who develop the disease.