Little worms? Ugh. It's a good thing that's called vermicelli in the United States or sales would be down considerably. How many people know at least someone who "visualized" bloody worms when they see spaghetti, anyway? Don't laugh -- that is a common condition that drives people away from pasta dishes.
At any rate, calling vermicelli "little worms" in the United States could only increase the number of people who associate disturbing images with pasta.