DES MOINES, Iowa (AP) — Officials say a rare illness that can paralyze children has been confirmed in two Iowa cases and is suspected in one Nebraska case.

The federal Centers for Disease Control and Prevention says at least 62 cases of acute flaccid myelitis have been confirmed in 22 states this year.

Dr. Mark Rupp is an infectious disease specialist for Nebraska Medicine in Omaha, and he says it’s “a mysterious disease, very rare and there’s a lot that we don’t understand about this.”

Iowa state medical director Caitlin Pedati says both Iowa patients were younger than 18 and were treated and then released from hospitals in western and central Iowa.

Health officials in Nebraska’s Douglas County say they’re investigating a possible case that could take up to three weeks to confirm.