Although it is true that most retroviruses gradually lose their infectious powers, some retain their ability to leap out of the host DNA--often much later. Certain pig retroviruses are probably among these.

• 虽然大多数逆转病毒确实逐渐失去了它们的传染力，但是有一些保留了跳出寄生体脱氧核糖核酸的能力----通常要更晚，某些猪的逆转病毒可能就在其列。