Persistence of Highly Pathogenic and Low Pathogenic Avian Influenza Viruses in Footbaths and Poultry Manure.

A questionnaire was designed in order to gather information about bedding material and footbath preparation and maintenance in different productive units across the state of California.This information was used to plan two experiments. In the first experiment, we tested the effectiveness of footbaths in inactivating highly pathogenic (HP) and low pathogenic (LP) avian influenza viruses (AIVs) on rubber boots. Surprisingly, quaternary ammonia- and quaternary ammonia + glutaraldehyde-based footbaths were not able to eliminate live HPAIV (H5N8) and LPAIV (H6N2) particles on boots, while a chlorine-based granulated disinfectant was able to destroy the virus at contact. These results demonstrated the potential of AIV, particularly the HPAIV isolate, to persist even if exposed to disinfecting footbaths, and suggest that footbaths, as a single tool, are not capable of preventing pathogen introduction into commercial flocks. In the second experiment, we investigated the persistence of HPAIV (H5N8) and LPAIV (H6N2) in bedding material and feces obtained from turkey, broiler, and egg-layer commercial productive units. Samples were collected at different times after spiking the bedding materials and feces. Results showed that HPAIV (H5N8) was more persistent than LPAIV (H6N2) in layer feces and bedding material obtained from commercial broilers and turkeys. Live HPAIV particles persisted 96 hr, the last time point measured, in layer feces and less than 60 hr in broiler and turkey bedding. In contrast, LPAIV persisted less than 24 hr after being spiked in all the different substrates. Further research in biosecurity practices such as footbath preparation and maintenance and better understanding of the mechanism of the increased persistence of AIV is warranted in order to identify effective litter treatments that destroy live virus in bedding material.