I wouldn’t kill the thousand, only because I know the billions NEED TO die. WIth a disease as described, 90% of every other kind of mammal would die, too.
I would happily sit back and let the human race be reduced to 1/10th its current population by a natural event that didn’t cause wide-spread destruction. A little rioting, a big mess to clean up, but the U.S. could readily recover from such an event. From nearly 400,000,000 to 40,000,000 would still be a viable population to keep civilization going.
The plague would be horrible, but not as bad as total war, which is always looming.
It would knock the whole ‘carbon footprint’ down approximately 90% too, and give the planet a break to recover a bit, which might be enough to prevent worse damage to the biosphere.
Upheaval is interesting and good.
Stagnation is boring and bad.