在发展中国家,急性下呼吸道感染(ALRI)是儿童发病及死亡的一个非常重要的原因,对付这些疾病的一种方法是鼓励基层卫生保健人员应用经验的方法诊断和处理;另一种方法是预防。营养不良(包括维生素A缺乏)及肺防御机制的慢性寄生感染的影响尚不清楚,病毒感染及细菌性疾病的交互作用也需要阐明,对肺炎病原体的非免疫抵抗因素及抗原特异 In developing countries, acute lower respiratory tract infection (ALRI) is a very important cause of morbidity and mortality in children. One way to deal with these diseases is to encourage primary health care practitioners to diagnose and manage the disease using experience. The other is prevention. The impact of malnutrition (including vitamin A deficiency) and chronic parasitic infections with lung-defense mechanisms is unclear, and the interaction between viral infections and bacterial diseases needs to be clarified. Non-immune and pneumococcal pathogens