A common eye bacteria known as Chlamydia pneumoniae has been associated with cognitive decline, including Alzheimer’s disease and various forms of dementia. This prevalent bug is believed to infect up to 80% of adults at some point in their lives, often presenting with mild symptoms such as a sore throat or fatigue. However, researchers from Cedars-Sinai Health Sciences University in Los Angeles have found a potential link between higher levels of this bacteria and advanced degeneration in individuals with Alzheimer’s disease.
Although the correlation does not prove causation, the study suggests that chronic infections like Chlamydia pneumoniae may play a role in neurodegenerative diseases over time. Professor Maya Koronyo-Hamaoui, the study’s lead author, highlighted the discovery of a connection between bacterial infection, inflammation, and neurodegeneration. The research indicates that retinal bacterial infection and chronic inflammation could reflect brain pathology, potentially predicting disease status and identifying individuals at risk for Alzheimer’s through retinal imaging.
The study, published in the scientific journal Nature, involved the analysis of eye and brain tissue from 104 deceased individuals. The presence of C. pneumoniae in the eye and brain showed a clear association with Alzheimer’s diagnosis and more severe cognitive decline. The findings offer hope for targeted treatments in Alzheimer’s disease, which affects millions of people globally and is a leading cause of death, particularly for women.
Recent European surveillance data indicates a significant rise in C. pneumoniae cases in 2024, possibly due to reduced exposure to everyday bacteria during pandemic lockdowns. This surge underscores the importance of understanding the impact of bacterial infections on cognitive health and the need for preventive measures.
