Affected mothers lose up to 10 percent of their pregnancies. Their babies are spontaneously aborted or are stillborn. As many as 20 percent to 30 percent of survivors may suffer and die from respiratory disease, such as pneumonia. The PRRS virus is said to primarily attack a pig's immune system, leaving the body open to a host of other infections, particularly in the lungs. Some pigs develop a chronic infection and become carriers but show no symptoms.
Research reveals that the virus is transmitted via semen, saliva and blood.
Those pigs herded closely together and transported at close quarters by trucks may be more susceptible to infection. To date, there is no evidence that the virus can infect humans from any source, including via food. Researchers looking for signs of the virus in pig meat haven't found any. No Virus Trace in People or Meat Beth Lautner, vice president of science and technology at the National Pork Producers Council, says PRRS is a complex disease, acknowledges that some of the symptoms are AIDS-like and notes that no trace of the disease has been found in people or meat. Monte McCaw, a PRRS researcher with North Carolina State University's College of Veterinary Medicine, believes that while the differences between PRRS and AIDS are obvious to researchers, it is also important to study the similarities.