Intervention strategies for carcass disposal: pareto analysis of exposures for exotic disease outbreaks.

An enhanced methodology for the policy-level prioritization of intervention options during carcass disposal is presented. Pareto charts provide a semiquantitative analysis of opportunities for multiple exposures to human health, animal health, and the wider environment during carcass disposal; they identify critical control points for risk management and assist in waste technology assessment. Eighty percent of the total availability of more than 1300 potential exposures to human, animal, or environmental receptors is represented by 16 processes, these being dominated by on-farm collection and carcass processing, reinforcing the criticality of effective controls during early stages of animal culling and waste processing. Exposures during mass burials are dominated by ground- and surface-water exposures with noise and odor nuisance prevalent for mass pyres, consistent with U.K. experience. Pareto charts are discussed in the context of other visualization formats for policy officials and promoted as a communication tool for informing the site-specific risk assessments required during the operational phases of exotic disease outbreaks.

Exposure assessment of carcass disposal options in the event of a notifiable exotic animal disease: application to avian influenza virus.

We present a generalized exposure assessment of 28 disposal options for poultry carcasses in the event of a highly pathogenic avian influenza (HPAI) outbreak. The analysis supports a hereto unverified disposal hierarchy for animal carcasses, placing waste processing (e.g., incineration and rendering) above controlled disposal (e.g., landfill), above uncontrolled disposal (e.g., burial on-farm). We illustrate that early stages of the disposal chain (on-farm) pose greater opportunities for exposure to hazardous agents than later stages, where agents are generally contained, wastes are treated, and residues are managed by regulated processes. In selecting carcass disposal options, practitioners are advised to consider the full range of hazards rather than focusing solely on the HPAI agent, and to give preference to technologies that (i) offer high destruction efficiencies for target pathogens; (ii) do not give rise to significant releases of other pathogenic organisms; and (iii) do not release unacceptable concentrations of toxic chemicals. The approach offers an exposure assessment perspective for carcass disposal, thus providing a risk-informed basis for contingency planning and operational intervention. The authors recognize that relevant legislation, public perception, available capacity, and cost also need to be considered when selecting disposal options in the event of HPAI.