HONOLULU (AP) — A California couple on their honeymoon and two people who drank a homemade herbal beverage are among the rising number of victims in Hawaii falling ill with a potentially deadly brain parasite.

After the newlyweds' plight with rat lungworm disease recently got attention online, the couple and some experts accused Hawaii of failing to adequately warn tourists and residents of the danger they can face.

Tourism officials say the disease is rare and there's no need to cancel vacation plans.

Hawaii has seen the same number of infections so far this year that it'll often get annually. Eleven cases have been confirmed.

Dr. Virginia Pressler, state health department director, says the reason for the "concerning increase" isn't clear. But it could be blamed on a recent Maui influx of a semi-slug that can carry the disease.