Why was Harv sick in Diamond Age?

Question

Why was Harv sick in Diamond Age? Wouldn't they have technology to cure those kind of diseases? In other parts of the book, they used nanocytes as defenses to to 'cure broken capillaries in the buttocks'. Besides, he seems to come from hardy stock.

Answer 1

The sickness comes from all the nano tech in the air.

Part the First, Nell sees some­thing pe­cu­liar; Harv ex­plains all:

"See, there's mites around, all the time...They're in the air, in food and water, every­where. And there's rules that these mites are sup­posed to fol­low, and those rules are called pro­to­cols. And there's a pro­to­col from way back that says they're sup­posed to be good for your lungs. They're sup­posed to break down into safe pieces if you breathe one in­side of you." Harv paused at this point, the­atri­cally, to sum­mon forth one more ebon loo­gie, which Nell guessed must be swim­ming with safe mite bits. "But there are peo­ple who break those rules some­times. Who don't fol­low the pro­to­cols. And I guess if there's too many mites in the air all break­ing down in­side your lungs, mil­lions– well maybe those safe pieces aren't so safe if there's mil­lions."

As for why he wasn't cured, there's no specific cite but from the overall tone of the book Harv probably could have been cured if he was wealthy, powerful, connected, or "valuable". Since he's just a common street kid - tough luck.