African Swine Fever Outbreak Investigations-The Significance of Disease-Related Anecdotal Information Coming from Laypersons.

Veterinarians who have conducted numerous investigations of African swine fever outbreaks in pig farms in various European countries over the years shared their experiences during a workshop in Germany in early 2020. One focus was on the so-called "anecdotal information" obtained from farmers, farm workers or other lay people during the outbreak investigations. Discussions revolved around how to correctly interpret and classify such information and how the subjective character of the statements can influence follow-up examinations. The statements of the lay persons were grouped into three categories according to their plausibility: (i) statements that were plausible and prompted further investigation, (ii) statements that were not plausible and could therefore be ignored, and (iii) statements that were rather implausible but should not be ignored completely. The easiest to deal with were statements that could be classified without doubt as important and very plausible and statements that were not plausible at all. Particularly difficult to assess were statements that had a certain plausibility and could not be immediately dismissed out of hand. We aim to show that during outbreak investigations, one is confronted with human subjective stories that are difficult to interpret but still important to understand the overall picture. Here, we present and briefly discuss an arbitrary selection of reports made by lay persons during outbreak investigations.