However, we can piece together some clues:
* The virus was engineered: In the film, the main character, Robert Neville, mentions that the virus was a "cure" for cancer that went wrong. This implies that the plague was a result of human intervention, possibly a bioengineered virus that mutated and became highly contagious.
* It spread rapidly: The film depicts a world ravaged by the plague, suggesting that the virus spread rapidly and indiscriminately. This could be attributed to its highly infectious nature or lack of immediate symptoms, allowing infected individuals to spread it unknowingly.
* The virus transforms humans: The plague not only kills its victims but also transforms them into monstrous, nocturnal creatures. These "Darkseekers" are aggressive, undead-like beings, further emphasizing the horrifying and unique nature of the virus.
The film's focus is not on the specific scientific details of the plague but on its consequences for humanity and the individual struggle for survival. The lack of a detailed explanation adds to the mystery and mystique of the virus, leaving the audience to speculate and consider the potential dangers of unchecked scientific advancement.