Immunologically induced inflammation of the lungs of a susceptible host caused by repeated inhalation of a variety of substances including organic dusts. Included are molds and other fungi from sources such as cheese, vegetables, mushrooms, flour, mushroom compost, bark of trees, detergents, and contaminated humidification systems. In the acute stage, patients may present with cough, fever, chills, malaise, and shortness of breath. In the subacute and chronic forms, the onset of symptoms is gradual and prolonged. Treatment includes identifying and avoiding causative agents.