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Quantitative #risk #assessment of #human #H5N1 #infection from #consumption of fluid #cow's #milk

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By G.M.

Abstract

The spillover of highly pathogenic avian influenza H5N1 into dairy cattle has raised concerns over the safety of fluid milk. While no human foodborne infection has been reported, this strain has infected dozens of people and milk from infected cows is known to be infectious by ingestion in multiple other species. Investigation into the public health threat of this outbreak is critical. This study uses quantitative risk assessment (QRA) models to represent the United States raw and pasteurized fluid milk supply chains to estimate the risk of human infection from consumption of fluid cow's milk. These models were parameterized with literature emerging from this outbreak, then employed to estimate the H5N1 infection risk and evaluate multiple potential interventions aimed at reducing this risk. The median (5th, 95th percentiles) probabilities of infection per 240-mL serving of pasteurized, farmstore-purchased raw, or retail-purchased raw milk were 5.68E-15 (1.77E-16, 2.98E-13), 1.13E-03 (5.16E-06, 3.82E-02), and 1.02E-03 (5.20E-06, 3.64E-02), respectively. Our results demonstrate that pasteurization is highly effective at reducing H5N1 infection risk. Scenario analysis revealed quantitative real-time reverse transcriptase-polymerase chain reaction (qrRT-PCR) testing of bulk tank milk to be an effective method for reducing risk from raw milk. Additionally, we identify knowledge gaps related to human H5N1 dose-response by ingestion and raw milk consumption patterns. These findings emphasize the importance of pasteurization in protecting public health and will inform the implementation of control strategies to reduce the risk of human H5N1 infection from raw milk.

Source: MedRxIV, https://www.medrxiv.org/content/10.1101/2024.12.20.24319470v2

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