Infection-control CER

Claim: The highest-priority control for this cafeteria outbreak is a stay-home rule that keeps any food handler with vomiting or diarrhea out of the kitchen until 48 hours after symptoms stop.

Evidence: The chain trace showed norovirus spreading through the reservoir link, when one food handler who worked while sick shed virus onto serving utensils and ready-to-eat trays. From there the mode of transmission was fecal-oral contact through contaminated food, and the susceptible hosts were students whose only shared exposure was the lunch line. Handwashing and surface cleaning matter, but the sick worker was the source feeding the whole chain, and staff scheduling is a link the school controls directly.

Reasoning: Removing an infected reservoir shuts off the supply of new agent before it can ever reach a portal of entry. If no sick handler touches the food, there is nothing for handwashing or cleaning to catch up on later, so this breaks the chain at its source rather than trying to intercept virus that has already spread across trays and hands. Norovirus is shed in very high amounts and stays contagious for about two days after symptoms end, so a 48-hour exclusion targets the exact window when a returning worker is still a reservoir.

Expected effect: If the stay-home rule is enforced, foodborne transmission events of this type should drop sharply, because the single pathway in this scenario ran through food touched by an infected handler.

Assumptions and limitations: I assume the sick handler was the true source and that workers will report symptoms honestly rather than come in for a paycheck. If the virus actually entered through a contaminated food shipment or a sick student touching a shared drink station, exclusion alone would not be enough, and we would need to target a different link such as the mode of transmission or the portal of entry.