Historical perspective, an uncertain origin
Clinical outbreaks of an unknown disease characterised by severe reproductive losses in late gestational sows were noticedfor the first time in the late 1980’s.
The disease also affected piglets, increasing the number of weak-born and mortality rates in neonatal and nursery pigs, causing severe pneumonia and reducing growth performances.
The first outbreak of this new disease was reported in North Carolina, USA (1987). Just a few years later (1990), a clinically similar outbreak was described in Münster (Germany). No common link was found between the European and North American outbreaks. In the following years, it spread rapidly to other countries.
After using different names such as Mystery swine disease or Blue-ear pig disease, the current name Porcine reproductive and respiratory syndrome was finally adopted at the 1st International Congress on the disease (1992, USA).
Institute in Lelystad (The Netherlands) using porcine alveolar macrophages; the strain was named Lelystad virus. The Koch’s postulates were also fulfilled. One year later, the agent was isolated from the North-American outbreaks using cell line CL-2621; that strain was known as VR-2332.
Early genetic analysis demonstrated that:
- They were the same virus, but belonging to two distinct genotypes –nowadays, designated as two different virus species; PRRSV1 and PRRSV2-.
- They shared properties similar to other viruses from genus Arterivirus –known as Porarterivirus from 2016-.