Australian scientists have discovered what could be one of the few known causes of motor neurone disease.
The researchers have found that a toxin in blue-green algae can cause problems in the central nervous system leading to difficulty walking, breathing and swallowing.
Lead researcher Dr Rachel Dunlop from the University of Technology Sydney says the discovery comes from observing Guam's indigenous people, who are diagnosed with motor neurone disease at a rate 50 to 100 times more than the general population.
Dr Dunlop says those people were ingesting a large dose of the algal toxin through eating fruit bats.
She says the toxin can also be found in seafood.
Dr Dunlop hopes the discovery could lead to better treatment of the disease.