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Historic evidence to support a causal relationship between spirochetal infections and Alzheimer’s disease

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  • Prevention Alzheimer International Foundation

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Following previous observations a statistically significant association between various types of spirochetes and Alzheimer’s disease (AD) fulfilled Hill’s criteria in favor of a causal relationship. If spirochetal infections can indeed cause AD, the pathological and biological hallmarks of AD should also occur in syphilitic dementia. To answer this question, observations and illustrations on the detection of spirochetes in the atrophic form of general paresis, which is known to be associated with slowly progressive dementia, were reviewed and compared with the characteristic pathology of AD. Historic observations and illustrations published in the first half of the 20th Century indeed confirm that the pathological hallmarks, which define AD, are also present in syphilitic dementia. Cortical spirochetal colonies are made up by innumerable tightly spiraled Treponema pallidum spirochetes, which are morphologically indistinguishable from senile plaques, using conventional light microscopy. Local brain amyloidosis also occurs in general paresis and, as in AD, corresponds to amyloid beta. These historic observations enable us to conclude that chronic spirochetal infections can cause dementia and reproduce the defining hallmarks of AD. They represent further evidence in support a causal relationship between various spirochetal infections and AD. They also indicate that local invasion of the brain by these helically shaped bacteria reproduce the filamentous pathology characteristic of AD. Chronic infection by spirochetes, and co-infection with other bacteria and viruses should be included in our current view on the etiology of AD. Prompt action is needed as AD might be prevented.
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... Therefore, it is enormously important to investigate the involvement of pathogens in AD progression to better understand AD pathogenesis and therapeutic intervention. Indeed, several studies have identified the presence of different microbes in the post-mortem brain tissue of AD patients, suggesting they might be involved in AD (Renvoize and Hambling, 1984;Miklossy, 1993Miklossy, , 2011Miklossy, , 2015Itzhaki et al., 1997;Riviere et al., 2002;Alonso et al., 2014;Pisa et al., 2015;Perry et al., 2016;Dominy et al., 2019;Ciaccio et al., 2021;Senejani et al., 2021). ...
... In addition to viruses, bacteria that can reach the brain generally will induce neuroinflammation, and subsequent neurodegeneration which are the major cascades of AD pathology (Balin et al., 1998;Lim et al., 2014;Tran et al., 2022). A series of investigations found different kinds of spirochetes in human AD brain tissues, possibly revealing a strong connection of these microbes with AD pathogenesis as well (Miklossy, 1993(Miklossy, , 2011(Miklossy, , 2015. Borrelia burgdorferi, the causative agent of Lyme disease, was detected in AD brains, as a co-localized form with amyloid markers (MacDonald and Miranda, 1987;Senejani et al., 2021). ...
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... Researchers have observed the presence of T. pallidum and an increased number of spirochetal plaques in the cerebral cortex of certain patients diagnosed with general paresis (GP), suggesting the invasion of the central nervous system by T. pallidum in individuals affected by syphilis. When the cerebral cortex shows extensive deterioration or manifests dementia symptoms, this condition is commonly referred to as "general paralysis of the insane" (GPI), "dementia paralytica," or simply "general paralysis" (Miklossy, 2015;Chakravarthi and Joshi, 2021;Ha et al., 2024). ...
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