A study has found that the compound, called 1-octen-3-ol, leads to the degeneration of two genes involved with the transport and storage of dopamine, the neurotransmitter in the brain that is lost in patients with Parkinson’s.

The researchers suggest that the volatile substances given off by mildew and other fungi growing in damp houses may be a significant risk factor in the development of the degenerative brain disease, which is thought to have environmental as well as genetic causes.

The study was carried out on the dopamine system of fruit flies, a recognised animal “model” of Parkinson’s disease, and the researchers calculated that mushroom alcohol was more toxic to these specialised nerves than benzene – a poisonous chemical known to cause genetic damage.

“These findings are of particular interest given recent epidemiological studies that have raised the concern of neuropsychological impairments and movement disorders in human populations exposed to mouldy and water-damaged buildings,” the scientists said in the study published in the journal Proceedings of the National Academy of Sciences. “Increased incidence of Parkinson’s disease is seen in rural populations, where it is usually attributed to pesticide exposure. However, the prevalence of mould and mushroom in these environments may provide another plausible risk factor for the development of Parkinson’s disease.”

Until recently, the search for environmental factors that could trigger the disease has focused largely on man-made chemicals, such as pesticides. However, natural compounds could be equally to blame, said Arati Inamdar of Rutgers University.

“There have been studies indicating that Parkinson’s disease is increasing in rural areas, where it’s usually attributed to pesticide exposure. But rural environments also have a lot of exposure to moulds and other fungi, and our work suggests that 1-octen-3-ol might also be connected to the disease, particularly for people with a genetic susceptibility to it,” she added.

Joan Bennett, co-author of the study, said she took an interest in the role of fungi in health after she became ill working in her flood-damaged house in New Orleans after Hurricane Katrina in 2005.

“I knew something about ‘sick building’ syndrome, because I am an expert in toxic fungi. I didn’t believe in it, because I didn’t think it would be possible to breathe in enough mould spores to get sick,” Professor Bennett said.

But when collecting samples while wearing protective gear, she fell ill. “While I was doing the sampling, I felt horrible – headaches, dizziness and nausea. I had a conversion experience,” she said.

Claire Bale, a spokesperson for Parkinson’s UK, said that the cause of Parkinson’s disease is one of the big unanswered questions.

“We already know that exposure to some chemicals can slightly increase the risk of Parkinson’s, and this is the first study to suggest that chemicals produced by fungi may play a part,” Ms Bale said.

“It is important to remember, this study was conducted using tiny fruit flies, so before we can really be confident about this new connection we need to see evidence from studies in people,” she added.