Risk Reduction Modeling of High Pathogenicity Avian Influenza Virus Titers in Nonpasteurized Liquid Egg Obtained from Infected but Undetected Chicken Flocks

Abstract

Control of highly pathogenic avian influenza (HPAI) outbreaks in poultry has traditionally involved the establishment of disease containment zones, where poultry products are only permitted to move from within a zone under permit. Nonpasteurized liquid egg (NPLE) is one such commodity for which movements may be permitted, considering inactivation of HPAI virus via pasteurization. Active surveillance testing at the flock level, using targeted matrix gene real-time reversed transcriptase-polymerase chain reaction testing (RRT-PCR) has been incorporated into HPAI emergency response plans as the primary on-farm diagnostic test procedure to detect HPAI in poultry and is considered to be a key risk mitigation measure. To inform decisions regarding the potential movement of NPLE to a pasteurization facility, average HPAI virus concentrations in NPLE produced from a HPAI virus infected, but undetected, commercial table-egg-layer flock were estimated for three HPAI virus strains using quantitative simulation models. Pasteurization under newly proposed international design standards (5 log10 reduction) is predicted to inactivate HPAI virus in NPLE to a very low concentration of less than 1 embryo infectious dose (EID)50 /mL, considering the predicted virus titers in NPLE from a table-egg flock under active surveillance. Dilution of HPAI virus from contaminated eggs in eggs from the same flock, and in a 40,000 lb tanker-truck load of NPLE containing eggs from disease-free flocks was also considered. Risk assessment can be useful in the evaluation of commodity-specific risk mitigation measures to facilitate safe trade in animal products from countries experiencing outbreaks of highly transmissible animal diseases.

Poultry food products—a source of avian influenza virus transmission to humans?

“…This indicates that properly cooked poultry meat and eggs do not pose a risk of infection [43]. Also, the standard industrial pasteurization protocols for a variety of egg products were found to sufficiently reduce risks of AIV transmission [44][45][46].…”

Avian influenza

“…Non-pasteurised liquid egg (NPLE) is a commodity for which movements from a HPAI-affected area to a pasteurisation facility in a disease-free area may be permitted considering the inactivation of HPAI virus via pasteurisation. Weaver et al (2015) estimated HPAIV concentrations in NPLE for different scenarios of disease detection in an affected holding. The HPAIV concentration seemed to be highest when the disease was identified in a flock based on high mortality recognised via passive surveillance.…”

“…Weaver et al. () estimated HPAIV concentrations in NPLE for different scenarios of disease detection in an affected holding. The HPAIV concentration seemed to be highest when the disease was identified in a flock based on high mortality recognised via passive surveillance.…”