What is the main effect of prion diseases?

Prion diseases primarily lead to neurological degeneration. These diseases are caused by abnormal proteins, known as prions, which trigger misfolding of normal proteins in the brain. This misfolding results in brain damage, leading to a range of neurological symptoms such as memory loss, changes in behavior, and motor dysfunction. Over time, the accumulation of misfolded proteins causes irreversible damage to brain tissue, resulting in significant neurological decline.

The other options describe phenomena that do not align with the pathology of prion diseases. For instance, bacterial infections arise from bacterial pathogens and are not related to prion activity. Likewise, prion diseases do not bolster the immune system or produce toxins in the way that other infectious diseases might. Instead, they represent a unique category of neurodegenerative conditions, making neurological degeneration the hallmark effect of prion diseases.