There is asthma among farmers , especially in late summer. Darke et al. (1976) consider various types of mold, which may be contained in the form of impurities on cereal products and cause asthma during harvesting, especially when a large amount of fine dust is formed when using new mechanical methods of harvesting fields. Sometimes one agent can be identified.
For example, in farmers with asthma symptoms at the end of August during threshing, especially in those years when wheat was affected by rye, precipitins were found and positive skin tests were obtained against Septoria nodatum (Couch, personal communication). Allergic reactions to the grain itself have also been described [Wolfromm et al., 1966]. Millers and bakers develop an allergy, and they get asthma due to contact with wheat weevil (Sitophilus granarius), whose role was confirmed by bronchial provocation [Lunn, Hughes, 1967].
This reaction is of particular interest, since the immediate development of asthma is apparently associated with a late restrictive type defect and is sometimes accompanied by a double skin reaction and the presence of precipitins in serum. Immediate skin tests for weevil were also obtained [Lunn, 1966]. Flour, not containing impurities, after provocation in sensitized individuals also caused both immediate and “late” reactions.
Wood dust for occupational asthma
Persons who come into contact with hard rocks hardwood, there may be asthmatic symptoms in the evening or at night after contact. Due to this time lag, it is easy to overlook the connection between symptoms and contact. Gandevia and Milne (1970) observed late bronchial reactions to western red cedar, which lasted several days after cessation of contact. In these patients, skin and serological tests were negative.
Sosman et al. (1969) described double reactions in bronchial tests on mahogany, an immediate reaction to oak and late reactions on cedar, with each wood extract causing the appearance of the corresponding precipitins. However, in this work, which was carried out in limited mash-bahs, skin tests were negative. Pickering et al. (1972) observed a double reaction to a solid iroko tree in a patient who also had specific precipitations, and a late reaction in another patient who was in contact with Western red cedar extract.
Thus, in the analysis of individual cases, we cannot find any patterns among immunological signs. Undoubtedly, in order to clarify this issue, it is necessary to undertake more detailed studies, taking into account the sources of errors in the search for precipitins and skin tests.