Strict Biosecurity and Epidemiological Segmentation Enable Partial Culling During a Highly Pathogenic Avian Influenza Outbreak.

Background: The mandatory procedures to be followed after official confirmation of an outbreak of category A animal infectious diseases, including highly pathogenic avian influenza (HPAI), is laid down in European and national legislation. Typically, an outbreak of HPAI results in the destruction of the entire poultry population on the affected holding. Case Presentation: The presented case reports a deviation from this approach, demonstrating the practicality of partial culling in a highly biosecure, epidemiologically segmented holding. These on-site circumstances together with the specific risk assessment led to the elimination of only the affected unit, thereby inhibiting the further spread of the disease. After the destruction of the respective unit (farm), the other farms were closely monitored and tested continuously negative for HPAI virus (HPAIV) despite intensive systematic sampling. In the end, this procedure saved approximately 138,000 animals, ie 75% of the poultry population of the holding from destruction. Conclusion: This case demonstrates the effectiveness of proper management and high-level biosecurity to avoid excessive destruction of animals in case of an infectious disease outbreak. It might be suitable as a best-practice example in similar situations.