Twenty-first century contagious diseases require more than basic health lessons to prevent transmission. This Digest examines ways to prevent disease transmission in school settings. Section 1 discusses key concepts in contagion education: all people are potentially contagious; germs that cause diseases are present on many parts of the body; hand washing is essential; correct use of biohazard labels and containers is essential; and needles and other sharp objects should be handled appropriately. Section 2 describes universal precautions: using personal protective gear when exposure to body fluids is possible; removing and disposing of personal protective gear correctly; washing hands and contaminated; body areas immediately with soap and water; seeking medical attention for significant exposure to another person's blood; cleaning surfaces and/or solid objects that may be contaminated; and using pickups for collecting sharp objects. Section 3 examines what this means for classrooms: students should not share items which could transmit disease; students should learn how to dispose of their own hazardous waste; students can learn to attend to their own first aid needs; students should learn how to dispose of sharp objects and other people's litter; and school personnel must model correct contagion protection behavior. (Contains 10 references.) (SM)