造成寄生虫病流行的基本环节是 ["A．传染源和传播媒介","B．传染源和易感人群","C．传播媒介和易感人群","D．只有传染源","E．传染源、传播媒介和易感人群"]
磨蚀作用
感染阶段的定义是 ["A．寄生虫感染宿主的阶段","B．寄生虫感染终宿主的阶段","C．寄生虫感染人体的阶段","D．寄生虫的幼虫阶段","E．寄生虫的成虫阶段"]
下列不属于虫媒病的是 ["A．丝虫病","B．疟疾","C．疥疮","D．登革热","E．鼠疫"]
可经卵传递的传染性疾病是 ["A．登革热","B．黑热病","C．鼠疫","D．流行性斑疹伤寒","E．丝虫病"]
风积现象
