Bioaerosols: Generation and Transport From Confined Animal Operations.

Intensification and industrialization of cattle, swine, and poultry production are predicted to increase globally as the concurrent demand for high-quality protein also increases. Because animal confinement increases the microbial load within production facilities, on-site and near off-site exposures to airborne microorganisms and microbial byproducts (i.e. bioaerosols) are higher than in natural background environments. The inhalation of bioaerosols or ingestion after deposition on food crops and fomites, can be detrimental to health through infection, allergy, or toxicosis. The purpose of this presentation is to review the current state of knowledge with respect to identification of biological threat agents in aerosols and mechanisms of bioaerosol formation and their transport from animal housing. Much of the scientific data to date shows that bioaerosol concentrations are elevated within and in the immediate vicinity of housing units, but decrease with downwind distance from the animal facilities. While these results do suggest a low risk to individuals in the downwind environment, the data sets are limited since they are based primarily on the cultivation of airborne microorganisms. Molecular based approaches have been implemented to increase the detection of airborne pathogens; however, artifacts of sampling, complex meteorological conditions, and low ambient pathogen concentrations often make detection difficult. To improve estimates of bioaerosol transport from animal housing at confined operations, dispersion models should be considered a valuable tool and will be discussed as well.