From the other,empirical study indicate that PRDC tightly associates withporcine reproductive and respiratory virus(PRRSV) swine influenza virus(SIV) porcine circoviruses(PCV2) and mycoplasma hyopneumoniae,and PRDC is the cause of these virus.

• 实验研究从另一方面表明PRDC与猪呼吸与繁殖综合征病毒、猪流感病毒、猪圆环病毒2型、猪肺炎支原体有紧密的相关性,这四种病毒是原发原因。