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

Martin J Oettler,1,* Gerald Stumpf,2,* Katja Schulz,1 Matthias Todte,3 Klim Hüttner,4 Heidemarie Heyne,5 Thomas C Mettenleiter,6 Franz J Conraths,1 Carola Sauter-Louis1 1Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, 17493, Germany; 2Veterinary and Food Inspection Office, Güstrow, 18273, Germany; 3Veterinary Practice MMT, Köthen (Anhalt) 06366, Germany; 4Veterinary Epidemiological Service, State Institute for Agriculture, Food Safety and Fisheries Mecklenburg-Western Pomerania, Rostock, 18059, Germany; 5Animal Health Division, Ministry for Climate Protection, Agriculture, Rural Areas and the Environment of Mecklenburg-Western Pomerania, Schwerin, 19061, Germany; 6Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, 17493, Germany*These authors contributed equally to this workCorrespondence: Martin J Oettler, Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, Greifswald-Insel Riems, 17493, Germany, Email [email protected]: 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.Keywords: epidemiology, epidemiological unit, biosafety, infectious animal diseases, poultry