In the story I am writing, the United States never pulled out of Vietnam, with the conflict continuing into the present day. During this time, the United States decided to use Vietnam to secretly field test illegal bioweapons (since the USBWL was never disestablished), one of them being a genetically modified version of Ophiocordyceps unilateralis. The modified version of the fungus was designed to do two things: make the host kill and eat members of its own species, and use the nutrients from the consumed flesh to produce spores to spread to new hosts.
So, my questions are:
1) What modifications would be required to allow Ophiocordyceps unilateralis to infect humans?
2) How would Ophiocordyceps unilateralis modify the host's brain to cause the host to exhibit the behaviours stated above?