NEW YORK (AP) — More children have been diagnosed with a mysterious paralyzing illness in recent weeks, and U.S. health officials said Tuesday that they still aren't sure what's causing it.

This year's count could surpass the tallies seen in similar outbreaks in 2014 and 2016, officials said. Fortunately, the disease remains rare: This year, there have been 90 cases spread among 27 states, the Centers for Disease Control and Prevention said.

It's not clear what's causing some children to lose the ability to move their face, neck, back, arms or legs. The symptoms tend to occur about a week afte...