How soon after exposure should a sentinel be tested for a specific pathogen?

• A. Immediately
• B. Within 2 weeks after exposure
• C. 3 to 6 weeks after exposure
• D. 8 to 12 weeks after exposure

Answer: (C)

The timing being tested here hinges on how soon after exposure a sentinel will reliably show a positive result, which depends on the immune system’s response to the pathogen. After exposure, there’s a window period during which the animal may be infected but not yet have detectable levels of antibodies or pathogen markers. Testing too early can yield false negatives simply because the immune system hasn’t produced enough antibodies yet.

Testing three to six weeks after exposure hits a practical middle ground: it gives the immune system enough time to mount a detectable antibody response (seroconversion) for many pathogens, making serology-based surveillance more reliable. If you test immediately or within two weeks, some infections won’t be detectable. Waiting eight to twelve weeks can still detect antibodies, but it isn’t as efficient for timely surveillance and may miss dynamics of recent exposure. Since sentinel programs commonly rely on antibodies to indicate exposure, three to six weeks is the typical, robust window to test.