The impact of microbiological infections on neurodegenerative diseases

Neurodegenerative disorders are characterized by the loss of the nervous system functioning, resulting in varied symptoms for patients, which is evident in the literature in many details. The most common and extensively studied neurodegenerative disorders are Alzheimer's disease, Huntington's disease, Parkinson's disease, and amyotrophic lateral sclerosis. One of the typical hallmarks of these disorders, like protein aggregation, is often irreversible and, along with other hallmarks, leads to neuroinflammation. However, research is still being conducted to validate the cause versus consequence ambiguity. Numerous reports highlight the role of microbial infections in aggravating neuroinflammatory diseases. Infections caused by microbes create inflammation in the central nervous system by activating immune cells and infiltrating the peripheral nervous system's immune cells. These immune responses are exaggerated to protect the brain from microbial infections, but the aftereffects induce neuropathological changes leading to neurodegeneration. The role of microbes in disease onset and progression is evident in many studies, including those on worms, flies, mice, and humans. This chapter discusses how microbial infections impact and increase susceptibility to neurodegenerative diseases. The mechanisms behind the aggravation of neurodegenerative diseases because of microbial infections will be studied in this chapter, which may help therapeutic approaches prevent and slow neurodegenerative disease progression.