Reports from a number of states over the last 9 months have suggested that some swine herds have experienced a severe outbreak of reproductive failure, characterized by abortion and sow death. The outbreaks have been characterized by fever and anorexia in sows, followed shortly by abortions. The syndrome progresses rapidly and is often over within 3-6 weeks.
Abortions affect sows of all parities.
In addition to abortions, reports suggest that stillbirths, mummies and preweaning mortality may increase. However, the increases may be only moderate, and it appears that the syndrome is primarily focused on reproductive failure. Longterm ramifications of the episode on nursery and grow-finish pig performance have not been described. Diagnostic work in herds during the acute phase has indicated that PRRS virus is involved. Lesions compatible with PRRS can be seen in affected sows and wild field PRRS virus has been isolated from both sows and piglets.