四、副流感病毒肺炎副流感病毒肺炎（parainfluenzapneumonia）易感对象为3个月至1岁的婴儿。
O O B-dis I-dis I-dis I-dis I-dis I-dis I-dis B-dis I-dis I-dis I-dis I-dis I-dis I-dis O B-dis I-dis I-dis I-dis I-dis I-dis I-dis I-dis I-dis I-dis I-dis I-dis I-dis I-dis I-dis I-dis I-dis I-dis I-dis I-dis I-dis I-dis O O O O O O O O O O O O O O O O