If we unpack the implications of the fact that a single celled parasite like Toxoplasma gondii can develop a strategy to modify mammalian neurophysiology and behaviors to suit its own biological ends, we can begin to appreciate the fact that the community of friends and foes in our local biological relationship field set the tone for what we experience as life.
There is a full spectrum of relationships that is possible in any given biological community that can span the spectrum from obligate (necessary) mutualism to parasitic and predatory relationship dynamics where seizing the fruit produced by other organisms is the core behavioral property of the organism.
Depending on the biological community’s bias toward cooperation involving mutual nourishment and common defense, or toward parasitic and predatory relational dynamics, the organism based community will tend toward homeostasis (balance), or instability. This makes whether or not we learn about, and act to appropriately tend the many organisms from which our local biology is composed is a key factor in whether balance or imbalance (health or disease) will happen. It also plays a key role in defining our identity and shaping experience of life. This makes understanding and cultivating the biological relational system we are part of a critical factor in effectively steering our experience of life.
Here is an article outlining how a number of parasitic and predatory organisms press their agenda within the larger biological community. It is important to remember that there is a full spectrum of relationship possibilities, some of which bring nourishment, strength and health or defense of the integrity of the system against disruptive agents.