While the involvement of viruses in causing pneumonia in pigs is well recognized, many "new" agents and syndromes are being discovered. Some of the new agents are not even confirmed to be independently pathogenic, but have been found in herds that are having nursery or grower pig pneumonia problems. Also, with the arrival of PRRS, many multiple virus pneumonia cases are being reported. Some of these viruses are difficult to grow, but cause very unique lung lesions which have led pathologists and virologists to look harder for new viruses. Therefore, many of these diagnoses are made by excluding the common problems and by seeing atypical lung lesions that are compatible with what researchers have reported rather than by isolation.
A particularly serious nursery pig pneumonia problem is occurring in Quebec, Canada which appears to be caused by a mixed infection of PRRS and an atypical Influenza (flu) virus. This syndrome causes proliferative pneumonia, a unique and very serious pneumonia of pigs. There is a high rate of death loss, poor performance, and LACK OF RESPONSE TO ANTIBIOTICS (because it is a VIRAL disease syndrome).
The following is a list of viruses that are now associated with pig pneumonia:
(Iowa State University: Pat Halbur and Prem Paul)
Take-Home Message
Do not buy breeding stock before your veterinarian has thoroughly investigated the disease status of the supplying herd, particularly its nursery disease status! Most of these disease syndromes are not seen in North Carolina, so let's not import them! While canada is a source of excellent lean genetics, thoroughly investigate the disease status of any breeding stock herds there, especially from Quebec. Conversely, many Canadian herds are so clean that adding their animals directly into your herds may expose them to diseases they have never seen causing pneumonia, arthritis or even death.
