Which set of diagnostic modalities is commonly used in One Health for pathogen detection across humans and animals?

• A. Only PCR and culture are used for cross-species surveillance.
• B. Serology alone is sufficient for all cross-species surveillance.
• C. PCR, ELISA, culture, sequencing, and metagenomics are commonly used across humans and animals.
• D. Metagenomics is rarely used in One Health contexts.

Answer: (C)

In One Health, a broad diagnostic toolbox is used to detect, identify, and characterize pathogens across humans and animals. The best set includes PCR for targeting pathogen genetic material, ELISA or serology to assess exposure and immune response, culture to isolate live organisms for confirmation and further testing, sequencing to precisely identify and type pathogens, and metagenomics to survey all nucleic acids in a sample for broad detection, including discovery of novel agents. This combination provides direct detection of current infection, evidence of exposure, and detailed pathogen information across species, which is essential for effective cross-species surveillance and outbreak response.

Relying on a single modality, like only PCR and culture, misses information provided by serology, sequencing, and metagenomics. Serology alone doesn’t prove active infection or give pathogen identity; metagenomics is not rarely used in modern One Health contexts, as it enables discovery and comprehensive profiling across diverse hosts and environments.