猪圆环病毒（Porcine circovirus，PCV）是一种单链DNA病毒(class II)，无囊膜，单股环状。病毒衣壳呈20面体对称结构，直径约17 nm。猪圆环病毒属圆环病毒科圆环病毒属。

猪圆环病毒是在真核生物中自主复制的最小病毒病毒在感染细胞的核内复制，利用宿主的聚合酶进行基因组扩增。

猪圆环病毒共有两个毒株：I型和II型。猪圆环病毒I型首次发现于1974年，可以进行感染，但不会导致猪发病。病毒II型会导致猪发生断奶仔猪多系统衰竭综合征（postweaning multisystemic wasting syndrome，PMWS）。

Circovirus is a genus of viruses, in the family Circoviridae. Birds (such as pigeons and ducks) and pigs serve as natural hosts, though dogs have been shown to be infected as well. There are currently 11 species in this genus including the type species Porcine circovirus-1. Diseases associated with this genus include: PCV-1: non pathogenic PCV-2: postweaning multisystemic wasting syndrome (PMWS).