This post is from the MSHMP team looking at status IV farms and their PRRS incidence between the years 2009 and 2019. Quick reminder, in 2011, Holtkamp et al. defined status IV farms as PRRS-negative per their shedding and exposure status.
- PRRS incidence rate in status IV farms varied significantly from 2009 to 2019.
- The incidence rate in status IV farms during 2019 was one of the lowest on record and comparable to the one observed in 2013 and 2014; the years of the PED epidemic in the US.
- PRRS incidence in status IV farms during 2019 was significantly lower than the one of 2015 and 2016 and marginally non-significant lower (p=0.07) than the one of 2018.