Cordyceps Brain Infection

The Cordyceps Brain Infection (abbreviated as CBI) is a parasitic fungal infection that has devastated mankind in Black Blood.

History
The fungus grows while the host is still alive, with hosts undergoing four stages of infection. Stage one begins within two days of infection, wherein the host loses their higher brain function (and with it, their humanity), rendering them hyper-aggressive and incapable of reason or rational thought.

Within two weeks, the host enters stage two of the infection, wherein the fungus begins altering their sight as a result of progressing fungal growth over the head and corruption of their visual cortex.

After a year of infection, the infection enters stage three; scarring their face and blinding them, resulting in them developing a primitive form of echolocation to compensate.

In very rare cases, if the host survives for over a decade, they reach stage four. They develop hardened fungal plates over most of their body.

When the fungus kills the host, the host's body grows stalk-like fungal projections which release infectious spores. The infection can also be spread through bites from living hosts. Hosts can only be infected while alive, as the fungus is unable to infect dead bodies due to its parasitic nature, though dead Infected can release spores regardless of stage.