Why are sentinels less effective for detecting certain viral pathogens like Sendai virus?

Sentinels, or sentinel animals, are used in laboratory settings to monitor the health status of other animals and detect potential infections. They are particularly effective in identifying pathogens that are more prevalent or transmitted through certain routes.

The reasoning behind the effectiveness of sentinels in detecting fecal-oral pathogens lies in their exposure to the environment in which other animals are housed. These sentinels can pick up these types of pathogens through contact with contaminated materials, such as bedding or food. However, certain viral pathogens, such as the Sendai virus, may not be as readily detected as they often spread through respiratory routes or close contact rather than through fecal or oral transmission.

Since the sentinel animals are not specifically exposed to viral agents like Sendai virus in an efficient manner compared to fecal-oral pathogens, their capability to act as robust indicators for these particular viruses becomes limited. Therefore, while sentinels are helpful in many aspects of pathogen detection, their utility is context-dependent, and they may not be the best indicator for viral infections that have different modes of transmission.