Transmission Interaction Persistence (TIP): A Supply Chain and Epidemiological Model for Zoonotic Virus Outbreaks

Problem definition: Zoonotic viruses that jump from animals to humans, like avian influenza or severe acute respiratory syndrome, have caused major pandemics in recent decades. Many of these pandemics originated in China, a major supplier and consumer in the global food supply chain, and in other low- and middle-income countries. Interestingly, these outbreaks have been linked to live animal markets, even when the surrounding farms supplying markets had very low infection prevalence. This suggests that these markets potentially amplify and propagate the spread of zoonotic viruses. Yet, traditional epidemiological models cannot explain the observed outbreaks in these markets. Methodology/results: This paper introduces an epidemiological model that integrates supply chain and in-market operational dynamics to explain the role of markets in zoonotic virus spread, focusing on avian influenza. The transmission, interaction, and persistence model incorporates stochastic supply chain and in-market dynamics into traditional epidemiological frameworks. The analytical results demonstrate how major outbreaks could occur in markets, even when the infection prevalence among animals sourced from the surrounding farms is very low, and animals remain in the market for less than a day. This is the result of two important dynamics. The first is concerned with the supply chain structure in which markets serve as a consolidation point of agricultural inputs from many small farms. The other is driven by in-market operations that affect environmental in-market infection evolution, particularly persistent infection through two-sided interactions between animals and wastewater, surfaces, and feed that exist in the environment within the market. Managerial implications: This paper highlights the important role of supply chain structure and market operational dynamics in influencing environmental infections and facilitating the spread of zoonotic viruses. Additionally, the TIP model enables the evaluation of the effectiveness of critical in-market and supply chain interventions to prevent infection outbreaks. History: This paper was selected as part of the 1RR initiative between the M&SOM Journal and the MSOM Society. This paper was part of the 2024 MSOM Supply Chain Management SIG Conference. Funding: The work of E. G. Zerhouni was partially funded by an award from the Walmart Foundation. Supplemental Material: The online appendices are available at https://doi.org/10.1287/msom.2024.1318 .