  The transmission dynamics of infectious diseases in animal production are
driven by several propagation routes. Contaminated vehicles traveling between
farms have been associated with indirect disease transmission. In this study,
we used transportation vehicle data to analyze the magnitude of farm visits by
different vehicles and to propose a methodology to reconstruct vehicle contact
networks considering pathogen stability and cleaning and disinfection
effectiveness. Here, we collected information from 6,363 farms and Global
Positioning System (GPS) records from 567 vehicles used to transport feed,
animals, and people. We reconstructed vehicle contacts among the farms,
conserving pathogen stability decay and different probabilities of cleaning and
disinfection. Results showed that vehicle movement networks were densely
connected, with up to 86% of farms connected by these movements. Movements of
vehicle transporting feed and pig among farms showed the highest network
connectivity. The cleaning effectiveness of was variable among the different
vehicle types and highly influenced by the frequency of vehicles stopping at
clean stations. A large number of between-farm contacts with a pathogen
stability >0.8 were present in the vehicle network even with 100% cleaning
effectiveness. Finally, we identified that vehicles contacted farms from
different companies. Thus, our results suggest the vehicle network is a
potential mechanism for spreading pathogens among farms. Moreover, even with
scenarios with high effectiveness of cleaning and disinfection, the risk of
vehicles spreading diseases was not completely eliminated.
