The modern anthropological view on religion is that it is a cultural meme that replicates through social communication . While the meme itself may influence behavior, religious icons are known to be vectors of infectious diseases . Most major religions have rituals that are likely to promote the transmission of infections. This includes circumcision , Christian common communion chalice , the Hindu ‘side-roll’ and Islamic ritual ablution  as well as the Hajj congregation in Mecca . For example, the latter is specifically associated with outbreaks of meningococcal disease .
Thus it is possible that various religious practices could represent biomemes: manifestations of a symbiosis between informational memes  and biological organisms. This concept is somewhat similar to the fictional midichlorians of the Jedi Order from the popular series “Star Wars”.
Two particular parts of the human body seem to be most promising for the search of behavior-altering parasites. First of all, the human gut microbiome may be of interest in light of the microbiome-gut-brain axis concept. Another promising area to search for behavioraltering parasites is the human brain. Several organisms that can bypass the mammalian blood–brain barrier and produce a latent infection without obvious symptoms are currently known. In mice with latent toxoplasmosis, Toxoplasma gondii cysts can be found in various regions of the brain, especially in the olfactory bulb, the entorhinal, somatosensory, motor and orbital, frontal association and visual cortices, the hippocampus and the amygdala . In humans the brain also appears to be an important site for Toxoplasma gondii cyst formation and the parasite is capable of infecting a variety of brain cells, including astrocytes and neurons [57-59].