Modelling and assessing additional transmission routes for porcine reproductive and respiratory syndrome virus: Vehicle movements and feed ingredients

Jason A. Galvis, Cesar A. Corzo, Gustavo Machado

Research output: Contribution to journalArticlepeer-review


Accounting for multiple modes of livestock disease dissemination in epidemiological models remains a challenge. We developed and calibrated a mathematical model for transmission of porcine reproductive and respiratory syndrome virus (PRRSV), tailored to fit nine modes of between-farm transmission pathways including: farm-to-farm proximity (local transmission), contact network of batches of pigs transferred between farms (pig movements), re-break probabilities for farms with previous PRRSV outbreaks, with the addition of four different contact networks of transportation vehicles (vehicles to transport pigs to farms, pigs to markets, feed and crew) and the amount of animal by-products within feed ingredients (e.g., animal fat or meat and bone meal). The model was calibrated on weekly PRRSV outbreaks data. We assessed the role of each transmission pathway considering the dynamics of specific types of production (i.e., sow, nursery). Although our results estimated that the networks formed by transportation vehicles were more densely connected than the network of pigs transported between farms, pig movements and farm proximity were the main PRRSV transmission routes regardless of farm types. Among the four vehicle networks, vehicles transporting pigs to farms explained a large proportion of infections, sow = 20.9%; nursery = 15%; and finisher = 20.6%. The animal by-products showed a limited association with PRRSV outbreaks through descriptive analysis, and our model results showed that the contribution of animal fat contributed only 2.5% and meat and bone meal only.03% of the infected sow farms. Our work demonstrated the contribution of multiple routes of PRRSV dissemination, which has not been deeply explored before. It also provides strong evidence to support the need for cautious, measured PRRSV control strategies for transportation vehicles and further research for feed by-products modelling. Finally, this study provides valuable information and opportunities for the swine industry to focus effort on the most relevant modes of PRRSV between-farm transmission.

Original languageEnglish (US)
JournalTransboundary and Emerging Diseases
StateAccepted/In press - 2022

Bibliographical note

Funding Information:
The authors would like to acknowledge participating companies, veterinarians at the study region. Additionally, we would like to thank Swine Health Information Center for funding the Morrison Swine Health Monitoring Project. This project was funded by the Fats and Proteins Research Foundation. This work was also supported by Food and Agriculture Cyberinformatics and Tools, 2020‐67021‐32462, proposal number 2019‐07452, from the USDA National Institute of Food and Agriculture.

Publisher Copyright:
© 2022 The Authors. Transboundary and Emerging Diseases published by Wiley-VCH GmbH.


  • animal by-product
  • contact networks
  • PRRSV transmission
  • swine disease dynamics
  • swine disease transmission
  • truck

PubMed: MeSH publication types

  • Journal Article


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