MIKE STOBBE - AP Medical Writer

NEW YORK (AP) -- Health officials remain perplexed by mysterious cases of severe liver damage in hundreds of young children around the world.

The best available evidence points to a fairly common stomach bug.

That virus hasn't previously caused this kind of problem in otherwise healthy kids.

Investigators in the U.S. and abroad are exploring a number of theories that might explain the mystery.

One possibility that's not yet proven: that the stomach virus and the coronavirus are combining to provoke a liver-damaging immune system response.