There seems to be quite a few examples of parasites taking over the behavior of insects in a way that leads to the death of the host. A couple of examples include:
- Spinochordodes tellinii: A nematomorph hairworm that causes crickets and grasshoppers to jump into water, and likely drown, as part of their life cycle.
- Ophiocordyceps unilateralis: A fungus that causes ants to leave their desired habitat for the habitat required for the fungus to reproduce while consuming the ants internal organs.
In mammals, a common example is:
- Toxoplasma gondii: A single celled parasite that appears to make rats attracted to cat pee in an attempt to continue its life cycle within the cat. Additionally, humans can be infected with Toxoplasma gondii via contaminated meat, vegetables, and cat feces. In fact, there is a study of Danish medical records from 45,788 women in which the rate of self harm increased 50% for women suffering from chronic toxoplasmosis and the rate of attempted suicide was 80% higher. However, direct correlation between the increases could not be linked to the these higher rates due to the possibility of other factors such as depression.
So it seems that there is some widespread evidence of parasites causing a host to act in a potentially lethal way, but the evidence that I could find for humans seems to be minimal and yet to be proven. Are there any examples of parasites causing humans to act in a risky, potentially deadly, manner?