PRRSV: Comparison of commercial vaccines in their ability to induce protection against current PRRSV strains of high virulence

Abstract

The significance of PRRS was enhanced with the emergence, in the fall of 1996, of unusually severe forms of this disease characterized by extensive reproductive failure. These severe forms of the disease occurred in farms that, for the most part, had records of previous exposure to the virus and had initiated, at some point in time, vaccination programs against PRRS. Cases of unusually severe reproductive failure (also known as “atypical PRRS”) have been observed in several parts of the Midwest and North Carolina.