In research co-funded by the Parkinson's Disease Society (PDS), researchers from Dresden and Cambridge universities have created the first mouse model that suggests how Parkinson's might spread in the brain.
The study, which has been published in the online journal PLoS ONE this week, saw mice being fed very low daily doses of rotenone, a pesticide.
It has been suggested that people who are exposed to pesticides for a long time are at a slightly increased risk of developing Parkinson's, with scientists seeing an increase in the protein alpha-synuclein inside the nerve cells of the spinal cord, brain and gut.
Dr Kieran Breen, the director of research and development at the PDS, said: "This new research also suggests that environmental factors like pesticides could indeed trigger Parkinson's in some people.
"Refining new animal models is key to understanding Parkinson's, and will be vital in our search for new ways to test drugs that will lead to better treatments and ultimately to a cure."
While exact global figures are not always available, it is estimated that four million people worldwide have Parkinson's disease.
Find the nearest Barchester care home.