Prevention is the primary means of control at this time. The PRRS virus is, as yet, far from completely understood. Modes of transmission, clinical effects, prevention and treatment are still under enormous scrutiny. Pathology Pathogenesis Many factors can influence pathogenesis including age, sex, breed, immune status, management and viral strain. Sero-negative animals of all ages can become infected via oronasal, oral, intramuscular, intrauterine, intravenous, or intraperitoneal routes.
Primary replication occurs in alveolar macrophages.
When pregnant sows and gilt s become infected late in gestation, the virus is able to cross the placenta and cause pathological lesions in the fetuses. There is no direct treatment for PRRS available at this point in time but supportive measures may have beneficial effects. They are administered by intramuscular injections to growing and breeding pigs. Prevention strategies are intended to keep PRRS virus out of a herd. Control strategies contain and minimize the effects of disease, if introduced.