Persistence of low and highly pathogenic avian influenza virus in reused poultry litter, effects of litter amendment use, and composting temperatures

Abstract

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 our 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 on the survivability of this virus. The highly pathogenic AIV was found to persist much longer than low pathogenic AIV (LPAIV) 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 the presence of broiler litter. Differing results were obtained in turkey litter where the virus persisted less than 48 h. Finally, when testing composting temperatures, LPAIV was inactivated in litter after 30 min of viral contamination but before the target temperatures were reached. In carcass material with and without litter, LPAIV survived for less than 30 min, before reaching 50°C or 60°C, showing a detrimental effect on LPAIV survivability. These studies provide information that helps improve the understanding of interactions between environmental factors and AIV.

Keywords

• avian influenza
• persistence
• litter
• compost
• carcass