Comparison between the 2013–2014 and 2009–2012 annual porcine reproductive and respiratory syndrome virus epidemics in a cohort of sow herds in the United States

摘要

The purpose of this study was to describe the 2013/2014 porcine reproductive and respiratory syndrome virus (PRRSV) epidemic in the United States and compare it with the previous 4 y of data from 2009 to 2012. A total of 371 herds participated in the study, representing nearly 1.2 million sows in 15 States. There were significantly fewer PRRSV cases during this study period and the onset of the annual epidemic was delayed approximately 3 wk. Cluster analysis revealed a pattern similar to previous years. The roles of spurious observations, increased awareness of PRRSV epidemics, and porcine epidemic diarrhea virus detection in the United States swine herd are considered.