Boren Syndrome
From Halopedia, the Halo wiki
Boren's Syndrome is a human disease caused by exposure to radiation. It has several symptoms including brain tumors, migraines, and amnesia. Without proper treatment, it may also cause death. It is treatable by thirty weeks of intensive chemotherapy.
It is a condition that Sergeant Avery Johnson has, caused by exposure to high yield plasma grenades. It was contracted when he used an entire crate of plasma grenades to hold off Covenant forces on Paris IV.
The condition has a curious side effect; it is the only known natural defense against the Flood organism. Boren's syndrome scrambles the neural synapses of a stricken person, which makes their physical processes too unstable for an Infection Form to control.
