Vehicles play an important role in PRRSV transmission

Researchers from North Carolina State University modelled different potential transmission routes for porcine reproductive and respiratory syndrome virus (PRRSV), and found that vehicles used to move not only animals, but also farm workers and feed, can be carriers for disease spread. Their findings are published in Transboundary and Emerging Diseases.

The researchers modelled nine modes of between-farm transmission of PRRSV based on data from three farms. The modes included: farm-to-farm proximity; pig movements; “re-breaks” for farms with a previous outbreak; between-farm vehicle movements (vehicles to transport pigs to farms, pigs to slaughterhouses, feed and farm personnel), and animal by-products (animal fat or meat and bone meal) in feed ingredients.

The model was used to estimate the weekly number of outbreaks and their locations. Those estimates were then compared to available outbreak data so that the researchers could quantify the contributions of each transmission route.

While pig movements and farm proximity were the leading causes of disease transmission, it was found that the vehicles used to transport pigs were a major factor in PRRSV spread, contributing up to 20% of infections. Animal by-products delivered via feed, on the other hand, were found to have little effect on transmission.

The aim of the model, researchers say, is to enable farmers to pinpoint areas where enhanced biosecurity and intervention efforts may be helpful.

Article: Galvis, J. A., Corzo, C. A., Machado, G. (2022). Modelling and assessing additional transmission routes for porcine reproductive and respiratory syndrome virus: Vehicle movements and feed ingredients. Transboundary and Emerging Diseases, advance online publication, doi: 10.1111/tbed.14488

[SOURCE: North Carolina State University]