Porcine Reproductive and Respiratory Syndrome

Outbreaks of undiagnosed reproductive failure occurred in North Carolina, Minnesota, and Iowa during 1987-1988 and were characterized by the presence of both respiratory and reproductive signs in swine herds. 29,35,36 The disease was referred to as mystery swine disease because no definitive cause could be assigned to it. Various other names given to this syndrome were disease 89, pig plague 89, SMEDI-like syndrome, swine reproductive failure syndrome, swine reproductive and respiratory syndrome (SRRS), and swine infertility and respiratory syndrome (SIRS) (Table 1). At the First International Symposium on SIRS/PRRS held at St. Paul, Minnesota, USA, a decision was made to call this syndrome PRRS and its virus PRRSV. By 1990, the disease had been detected in 11 states of the United States and 2 provinces of Canada. It was reported in the Munster area of Germany in late 1990, spread rapidly to other parts of Germany, and was called Seuchenhafter Spatabort der Schweine (SSS; infectious late abortion of pigs) and Epidemisch Spatabort der Schweine (ESS; enzootic late abortion of pigs). It was then detected in other European countries (The Netherlands, France, Belgium, England, and Denmark) and has been diagnosed in over 5,000 North European pig farms since late 1990. Although the disease has not been reported in Italy, Poland, Switzerland, and Australia, antibodies against PRRSV have been detected in swine herds in Italy and Poland. The disease is economically important because of the severe adverse effects on swine production, an increase of 20-30% in the stillbirth rate, and a loss of 1.5-2.0 piglets per sow per year. A loss of $250-500