Which of the following is NOT typically used as an active surveillance method for Salmonella enteritidis?

• A. Pullet testing
• B. Egg cultures
• C. Vaccination of hens
• D. Test dead-on-arrival chicks

Answer: (D)

Active surveillance means proactively and systematically checking the flock or its products to detect Salmonella enteritidis before problems arise. Testing pullets is a direct way to monitor colonization in young birds, catching infection early in the production cycle. Egg cultures similarly provide a routine signal of contamination along the egg production chain, allowing for timely actions. Vaccinating hens isn’t itself a surveillance activity; it’s a preventive measure aimed at reducing infection and shedding, used as part of risk-reduction programs rather than to monitor the infection status. Testing dead-on-arrival chicks, on the other hand, relies on birds that have already died and reflects what happened after the fact, not a planned, representative assessment of flock status. This makes it reactive and not suitable as a standard active surveillance method.