Alzheimer’s could be passed on by humans

The trigger for Alzheimer’s disease can be passed between people through contaminated surgical tools, a landmark study suggests.

Until now, scientists believed that the disease was mostly a consequence of old age and partly influenced by genes. The new findings raise the prospect that patients could develop dementia as a result of a hospital operation, a blood transfusion or dental work such as root canal treatment.

The study, published in Nature yesterday, is the first evidence that the “seeds” of Alzheimer’s — microscopic protein molecules — could be transmitted between humans. The discovery was described by the study’s lead scientist as a paradigm shift in the understanding of how Alzheimer’s develops.

John Collinge, professor of neurology at University College London, said: “You could have three