| Popis: |
In August, 1952, in Bauru, a city of 60,000 inhabitants, in the State of Sao Paulo, Brazil, the Public Health Service was notified within a few days of 150 cases of a particular type of bronchial asthma, and nine deaths were attributed to it. The illness simulated an epidemic. Allergic studies in 30 cases revealed that they were cases of bronchial asthma and other allergic manifestations of the upper respiratory tract brought about by allergy to castor-bean (Ricinus communis) dust. The etiologic proof was made by history; strongly positive cutaneous tests; passive transfer of the skin-sensitizing antibodies, and by experimental provocation of symptoms. The experimental reproduction of the symptoms was possible by placing 4 patients in a room in which had been nebulized for an hour a 1:10 solution of the allergen. The four patients had extremely severe attacks of asthma, one to three minutes after they went into the room. The cases of collective asthma coincided with the changes made in the method of extraction of castor-bean oil by hexane, which occurred one day before at the large mill operating for some years in the city of Bauru. A new outbreak of collective asthma identical with the first one was observed about a month later when the mill resumed work after a period of inactivity and observation demanded by the physicians of the Public Health Service. With the closing down of the mill for a year no new cases of asthma of a collective nature were observed. The mill is now working again using a method of catching the dusts in a water reservoir, based on the fact that the allergen is soluble in water and precipitated by alcohol. |
