Another possible explanation for the chills was that Dr. X's nanosites 
were seeking out and destroying the ones that H.M. Joint Forces had put in 
there, waging a turf war inside his body, and his immune system was doing 
overtime trying to pick up the carnage. Hackworth unexpectedly fell asleep 
before the dromond had even pulled away from her mooring mast, and had dreams 
about the murderous implements he had seen magnified on Dr. X's mediatron 
during his first visit. In the abstract they were frightening enough. Having a 
few million of them in his veins didn't do much for his peace of mind. In the 
end it wasn't as bad as knowing your blood was
full of spirochetes, which people used to live with for decades. Amazing what a 
person could get used to.