The brain microbiome: could understanding it help prevent dementia?

Long thought to be sterile, our brains are now believed to harbour all sorts of micro-organisms, from bacteria to fungi. How big a part do they play in Alzheimer's and similar diseases?

Nine years ago, Nikki Schultek, an active and healthy woman in her early 30s, experienced a sudden cascade of debilitating and agonising symptoms - including cognitive and breathing problems and heart arrhythmia - and was investigated for multiple sclerosis. But three brain scans and numerous X-rays later, there was still no diagnosis or treatment plan. It was like living in a nightmare, imagining not watching my children - three and five years old - grow up," says Schultek.

Now, speaking on a video call from North Carolina, she is as bright as a button and shows no signs of degenerative brain disease. It turned out she had multiple chronic infections, including Borrelia burgdorferi bacteria, which causes Lyme disease and which had stealthily reached her brain. Antibiotics restored her health, but B burgdorferi is hard to eradicate once in the brain. She may need maintenance treatment to keep the disease at bay.