Worm is actually, worm-like parasite, that usually invade someone's GIT through food and water intake. It can also infect the bloodstream or tissues and organs. They can cause symptoms either by their very presence or by depriving the body of nutrients (parasites, eat the nutrients of their host)

Their presence in liver, can, be only diagnosed with imaging test, like using ultrasonogram of the liver.

How does your friend feel?
Is she bothered with some symptoms?