Mites, microbes, and neurodegeneration: A unified environmental hypothesis for Parkinson's disease, Alzheimer's disease, and Lewy body dementia

Emerging evidence suggests that various microbes and mites may play a significant role in the pathogenesis of neurodegenerative diseases such as Alzheimer's disease (AD), Lewy body dementia (LBD), and Parkinson's disease (PD). The association between microbial exposure and these conditions raises the possibility that mites, as vectors or direct agents, could contribute to disease onset and progression. PD, with 15% or less of cases linked to genetics, highlights the importance of environmental factors in the remaining sporadic cases. Mites, known to harbor prions, suggest a potential mechanism for horizontal transmission. Mites can inject neurotoxins that may disrupt neurological systems, potentially leading to movement disorders, memory loss, and cognitive decline. Conditions like seborrheic dermatitis and rosacea, linked to mites such as <i>Demodex</i>, are highly prevalent in patients with PD and AD, and mite-induced inflammation may exacerbate disease symptoms. Mite infestations can cause systemic illness, including respiratory, gastrointestinal, and neurological disturbances. Due to their microscopic size, they are often undetected and potentially can swap DNA with humans. This article summarizes observations linking mite exposure to neurodegenerative diseases. In one family, a member was diagnosed with LBD following chronic skin issues and mite exposure, while another developed symptoms associated with PD. Mites may contribute through prion transmission, neurotoxin injection, or by triggering inflammation. A nationwide study found that scabies patients treated with lindane, a neurotoxic pesticide, had a significantly reduced PD risk, suggesting a protective effect. These findings underscore the urgent need for further research into mites and environmental triggers.