Classic Swine Flu

Key takeaway

A combination of good communication, refined welfare assessment and application of technology can combine to refine humane endpoints and reduce suffering in vaccine efficacy studies.

Background

Classical Swine Fever (CSF) is a contagious viral disease of both domestic and wild pigs. The acute form of the disease can cause acute, severe suffering. In challenge studies looking at vaccine efficacy, white blood cell (WBC) counts were successfully used to refine humane endpoints. Daily, real-time analysis of blood samples, using a flow cytometer, enabled significant decreases in white blood cell counts to be identified, so that pigs could be euthanased before suffering became severe.

Pig in straw

Refinements

  • Holding pre-start meetings before every study, to ensure that scientists, vets and animal technologists were all familiar with the experimental aims, design and practicalities.  This ensured a common understanding of humane endpoints, including pre-emptive endpoints based on WBC analysis and those based on welfare assessment.
  • Collecting and using nuanced observations,  e.g. observing the pigs after blood sampling or feeding. Those who were first to lie down, or whose blood took longer to clot after sampling, were often found to be the first to approach endpoints.
  • Blood sampling early in the morning, so the WBC count results could be used that day to help make decisions on humane endpoints.
  • Timing experiments so that the critical phase occurred early or mid-week, rather than at weekends when there were fewer staff in.
  • Establishing a WhatsApp group to improve efficiency logistics, e.g. sharing sample analysis results and welfare scoring results, enabling humane endpoints and associated post-mortems to be organised quickly if required.
  • Using microchips to record temperature without handling, and video monitoring as a supplement (but not substitute for) interactive monitoring by competent, empathetic staff.
  • Holding ‘washup’ meetings to review each experiment and identify further refinements.

Implications

Having appropriate welfare assessment, establishing early humane endpoints, and establishing open communication and transparency within the team are crucial to reducing severe suffering.

Work was funded under the VetBioNet part of Horizon 2020 program of the European Union, project number 731014.