- The results of this study suggest that it is difficult to generate an epidemic within the pig industry in GB via direct pig movements alone, whereas haulage by itself has the potential for spreading infectious diseases within the pig sector.
- Even with a contamination period (the duration in which lorries are left contaminated by pathogens and act as fomites, i.e. a combination of the pathogen survival period and the period before cleansing and disinfection) of less than 1 day, sharing haulage vehicles will increase the average number of premises that a pig farm may contact and transmit diseases by 60-80%.
- Results show that the number of farms that are assumed epidemiologically isolated from the rest of the network (either by only sending pigs to slaughter or due to standstill regulation) decreases, once the role of sharing haulage vehicles has been accounted for.
- Under the assumption that all links between farms are infectious and the contamination period is minimum (<1 day), haulage sharing increases the maximum number of farms infected within 7 days before the first detection (between 118 and 775 farms) compared to no haulage sharing (between 9 and 193 farms).
- Between April 2012 and March 2014 (incl.), private haulage companies (PHC) were used in 41% of all movements and 33% of the non-slaughter movements in GB, accounting for 83% and 78% of pigs moved, respectively. - Among the 827 PHC used to move pigs in GB and for which we know the number of registered vehicles, 146 (18%) PHC registered fewer vehicles than they need for pig transport per day, based on the mean number of movements and mean number of pigs transported per day. This suggests that some PHC regularly use their vehicles more than once per day.
- Among the 827 PHC used to move pigs in GB and for which we know the number of registered vehicles, 113 (14%) registered more vehicles than they need for pig transport per day, based on the mean number of movements and mean number of pigs transported per day. This suggests that some PHC may transport multiple species.