Persistence of Low and Highly Pathogenic Avian Influenza Virus in Reused Poultry Litter, Effects of Litter Amendment Use and Composting Temperatures

Summary Avian influenza has greatly impacted the commercial poultry industry worldwide. Limited knowledge exists on the interactions between avian influenza viruses (AIV) and the environmental factors associated with poultry farms. To improve existing understanding of AIV survival in various environmental conditions, experiments were conducted to investigate the persistence of AIV in reused poultry litter. Additionally, we investigated the effects of a litter acidifier, based on sodium bisulfate, as well as different composting temperatures in the survivability of this virus. Highly pathogenic (HP) avian influenza was found to persist much longer than low pathogenic (LP) avian influenza in litter material, regardless of the number of cycles the litter was used. No clear association was detected between litter cycle use and viral persistence. In terms of litter acidification, the acidifier amendment immediately inactivated LPAIV when directly mixed with the virus and in presence of broiler litter. Differing results were obtained in turkey litter where the virus persisted less than 48 hours. Finally, when testing composting temperatures, LPAIV was inactivated in litter after 30 minutes of viral contamination but before the target temperatures were reached. In carcass material with and without litter, LPAIV survived less than 30 minutes, before reaching 50 °C or 60 °C, showing a detrimental effect on LPAIV survivability. These studies provide information that helps improve the understanding of the interactions between environmental factors and AIV.