Below zero

1989. Two special services agents - Roberto Diaz and his partner Trini Romano - go on a task to Australia. In the local community, after the fall of the fragments of the space satellite, the pestilence began. It turns out that a fungus settled there - a mutant, a name, CordyCeps novus. He not only parasitizes, but also changes the behavior of infected.
The fungus sample is ultimately hidden in the US underground vault, but later the bunker is privatized and converted to a regular warehouse.
2019. "Alien" breaks out, and living creatures are in his way. It is unclear who was infected and who was lucky so far.
Roberto Diaz and Trini Romano are back in service again.
So, the main question, who whom?