In addition to such common problems as surgical wound and catheter-associated urinary tract infections, correctional facilities may have to deal with additional more obscure infections such as viral hepatitis B or sexually transmitted diseases. Infections may be transmitted via contaminated food, water, equipment, or blood products, or via air-borne organisms. Infection control procedures aim at eliminating the source of transmission. This includes handwashing, proper sanitation, adequate ventilation systems, and segregation of infectious patients. Threats and uncertainties associated with AIDS have resulted in the application of universal infection control precautions (applied to treatment of all patients regardless of human immunodeficiency virus status) and isolation of all body substances during handling. Adequate training of staff in these precautions is essential to infection control. Other infection control procedures focus on the environment and include cleaning and sanitation, decontamination, disinfection, and sterilization. Prevention of infectious disease requires employee cooperation, administrative support, education, and written policies.