This document is a letter from Dr. Derek Cox, Consultant in Public Health Medicine for NHS Orkney, informing parents and guardians about an outbreak of norovirus or "winter vomiting bug" affecting several schools and nurseries in Orkney. It notes that the virus spreads easily through contact with contaminated surfaces or objects. It emphasizes the importance of good hand washing and observing the "48 hour rule," keeping anyone experiencing vomiting or diarrhea isolated from others for 48 hours after their last symptom to help control the small outbreaks.