evidence: Similar to Braak’s hypothesis for Parkinson’s disease where an external pathogen would cause neuroinflammation [described earlier in the text (Braak et al., 2003)], pathogen-induced inflammation might also play a role in Alzheimer’s disease (Wyss-Coray and Rogers, 2012; Cappellano et al., 2013); for example T. gondii, which is an obligate intracellular parasitic protozoan (phylum Apicomplexa) that uses a variety of mammals as intermediate hosts (including humans), with the cat as the final one, causes the infectious disease toxoplasmosis (da Silva and Langoni, 2009). It has been described that it can induce immune response in the host and inflammation in the CNS, alteration in the levels of neurotransmitters, and direct infections of neuronal and astrocytic cells (in rat primary cell culture) (Luder et al., 1999). For these reasons, T. gondii can be considered a possible etiologic risk factor for Alzheimer’s disease (Nayeri et al., 2021).