Parents in the De Soto School District are being warned about an outbreak of scabies.
District 73 officials sent a letter home with students Thursday notifying parents that one high school student, a junior high student, and an elementary student have been sent home with the skin condition.
Scabies is caused by tiny mites burrowing beneath the skin. It's extremely itchy and highly contagious.
District officials say they are taking steps to disinfect schools.
Students with scabies can't return to school without a doctor's note.
De Soto is about 50 miles south of St. Louis in Jefferson County.