1. Though polio has been practically wiped out, there have been sporadic cases of the disease. 虽然小儿麻痹症已差不多被消灭，可是仍有一些零星的病例。
2. Outbreaks and sporadic human infection with swine influenza have been occasionally reported. 人感染猪流感病毒的暴发和散发病例时有报导。
3. What is known is that some types of viruses cause outbreaks of diseases in man—the epidemic types—while others causes only sporadic illness. 所知道的是，有些类型的病毒引起人的爆发性疾病（流行型），而另一些类型的病毒则仅引起散发性疾病。
英英解释
adj.
1. recurring in scattered and irregular or unpredictable instances
