Porcine reproductive and respiratory syndrome

Porcine reproductive and respiratory syndrome (PRRS) is a viral infection that can have devastating effects on a swine operation. An outbreak may cost more than $236 per sow in infected herds. The incidence, severity, and duration of disease range from acute abortion storms to subclinical or chronic infection. Diagnosis is based on typical clinical signs, histopathology, virus isolation, antigen detection, and various serologic techniques. The clinical signs of PRRS are variable and difficult to differentiate from those of the secondary infections associated with it. Management guidelines for prevention and control of PRRS depend on whether the virus is present on the farm. A depopulation method has succeeded in clearing the infection from a farm. Vaccines against the PRRS virus are now commercially available. Protective immunity develops 7 days after vaccination and persists for about 16 weeks.