I've always thought of Lavos as a virus. Comes, infects, breeds, dies.
What exactly does it infect? The Planet? Not at all. Lavos is clearly a parasite, not a virus. If Lavos were akin to a virus, it would have saturated the planet with Lavos spawns and detonated the planet, launching them out in to the cosmos.
He's a good parasite though. Without him, there would be no humans. Schala made this very clear with the whole spermatoza thing. Without him, Humans would not be at their stage or anything, they wouldn't be special since they would not be a thing torn by love and hate and other things. The savior is also the thing that would ruin the planet. But then again, the planet was closer to the dragonians anyway.
Also, the thing that bothers me is this.
The Black Omen was not damaged in the Destruction Rains in 1999AD. That may mean it's not just there. Also, the fact that in 2300AD, Queen Zeal sees the Earth all ruined and doens't really care. So, what does she want to be the Queen of if the planet is destroyed, and Lavos will die? This kind of shows that she is more in tune with him, and maybe Lavos will go away, and she will with him and be eternal with him.
Also, I don't think Lavos was like "OMG, this Zeal Queen bitch is sucking my energy". It may have been that the flame was being drained to much and the dreamstone had a bad reaction with it. Remember, the flame has more power than that and if it had evolved humans, and raised their society for all this time, then obviously energy was used in the process, and not a little amount. As I said, the reaction with the Dreamstone and Schala's fainting could have done something to the flame to activate Lavos' thing. Heck, even the gate produced could have been a safety measure for the arbiter to live.