Definitions & Scope

This document defines how specific criteria are interpreted and applied consistently across disease briefs. It also establishes general conventions for the MCDA framework.

Criterion-Specific Definitions

Beyond-Farm Spread (Criterion 3)

What is evaluated: Transmission pathways that operate independently of direct pig-to-pig contact and undermine farm-level biosecurity.

Included pathways:

  • Wildlife reservoirs (e.g., wild boar, rodents)
  • Insect vectors (e.g., mosquitoes, ticks)
  • Aerosol spread beyond farm boundaries
  • Long-term environmental persistence (e.g., soil, water contamination)
  • Contaminated feed or supply-chain materials

Explicitly excluded pathways:

  • Trucks and vehicles
  • Boots and footwear
  • Clothing
  • Equipment
  • Personnel

Rationale for exclusion: These excluded pathways are treated as pig-associated transmission occurring under imperfect biosecurity. They are assumed to be potential transmission routes for most diseases and therefore do not differentiate diseases under this criterion. The focus is specifically on pathways that operate independently of pig movements and that cannot be controlled through farm-level biosecurity alone.

Example applications:

  • A disease spread primarily by wild boar = "Biosecurity largely ineffective"
  • A disease with occasional wildlife involvement but primarily pig-to-pig spread = "Some bypass of biosecurity"
  • A disease controlled entirely by managing pig contact = "Farm biosecurity effective"

The framework separates antimicrobial resistance (AMR) concerns into two distinct criteria to avoid conflating pathogen biology with management practices.

Criterion 7: Pathogen's Ability to Develop and Spread Resistance

  • Focuses on the bug's inherent biology
  • Evaluates capacity for acquiring and disseminating resistance genes
  • Viral diseases automatically score "Low resistance risk" (no AMR mechanism)
  • Independent of how the disease is actually managed

Criterion 8: AMR Development Driven by Disease Management

  • Focuses on drug use patterns
  • Evaluates how much antimicrobial use this disease drives
  • Creates selection pressure for resistance across all bacteria
  • Independent of the pathogen's own resistance characteristics

Why separate? A disease might drive heavy antimicrobial use (high Criterion 8) but be caused by a virus with no AMR risk (low Criterion 7), or vice versa.

Zoonotic Criteria (Criteria 1 & 2)

Foodborne zoonosis (Criterion 1): Transmission through consumption or handling of pork products

Non-foodborne zoonosis (Criterion 2): All other routes of human infection, including:

  • Occupational exposure (farmers, veterinarians, slaughterhouse workers)
  • Aerosol transmission
  • Environmental contamination
  • Direct contact with infected pigs or their secretions

Important distinction: Mechanical transfer of pathogens on clothing or equipment is NOT considered zoonotic transmission. Zoonosis requires actual human infection, not just passive transport between pig populations.

General Conventions

Harm-Based Framework

All criteria are framed as harms, with levels progressing from least harm to greatest harm. This ensures:

  • Consistent interpretation across all criteria
  • Intuitive comparisons in PAPRIKA trade-off questions
  • Clear prioritization logic (diseases causing greater harm rank higher)

Level Ordering

Within each criterion, levels are strictly ordered from best outcome to worst outcome. In the PAPRIKA elicitation process and in 1000minds software, these levels should be entered in this exact order (lowest ranked to highest ranked).

Evidence Standards

Disease assessments should be based on:

  • Peer-reviewed scientific literature
  • National and international surveillance data
  • Laboratory diagnostic findings
  • Expert consensus when empirical data are limited
  • Field observations from practicing veterinarians

Speculative or theoretical risks should be clearly identified as such in disease briefs.

Scope of Analysis

Geographic focus: United States pig production systems

Population: Domestic commercial pigs (does not extensively address backyard/hobby farms, though principles apply)

Diseases included: The framework is designed to evaluate any pig disease, including:

  • Endemic diseases (currently present)
  • Foreign animal diseases (potential introductions)
  • Emerging diseases (recently recognized or novel)
  • Zoonotic and non-zoonotic diseases

Uncertainty Handling

When evidence is limited or conflicting:

  1. State the uncertainty explicitly in the disease brief
  2. Document the basis for the level assignment
  3. For Criterion 11 (Eradication feasibility), the level "Feasibility of eradication not known" is available for emerging diseases
  4. Consider seeking expert input from specialists in that disease area

Disease Brief Requirements

All disease briefs must:

  • Follow the standard template structure
  • Include the LEVELS line with exactly 11 semicolon-separated values
  • Provide justification for each criterion level assignment
  • Use level labels exactly as defined in the criteria framework
  • Include an overview paragraph describing the disease

Template location: docs/diseases/_template.md

PAPRIKA Methodology Notes

This framework is designed for use with the PAPRIKA (Potentially All Pairwise RanKings of all possible Alternatives) method implemented in 1000minds software.

Key principles:

  • Criteria and levels are defined before disease evaluation
  • Stakeholders make pairwise comparisons to elicit preferences
  • Trade-offs are presented as binary choices between disease scenarios
  • Level labels must be substantive and self-explanatory (not abstract terms like "high" or "low")

Stakeholder engagement:

  • Disease briefs serve as reference materials for PAPRIKA sessions
  • Criterion definitions should be reviewed with all participants before elicitation
  • Participants represent diverse perspectives (farmers, veterinarians, researchers, policymakers)

Revision History

This framework was developed through iterative refinement with stakeholder input. Key revisions include:

  • February 2026: Reduced from 12 to 11 criteria (removed "Containability" as redundant with other criteria)
  • February 2026: Renamed "External transmission" to "Beyond-farm spread" for clarity
  • February 2026: Renamed "Ability to detect" to "Detection difficulty" with reversed harm-framing
  • February 2026: Clarified AMR criteria to distinguish pathogen characteristics from antimicrobial use patterns
  • February 2026: Added "Feasibility not known" level to Eradication criterion for emerging diseases

Contact & Feedback

This framework is intended to be transparent and scientifically defensible. Feedback on criteria definitions, level descriptions, or disease assessments is welcome and will be considered for future refinements.

For questions or suggestions, contact the project team through the repository or documentation maintainer.