[Diseases connected with work in hay in Iceland. Causes and scientific studies]

Diseases connected with work in hay have been known in Iceland for a long time. In 1981 scientific studies of these diseases were started in Iceland at the request of the Farmers Union. The results of these studies are summarized in this article. In studies of hay a great amount of storage mites, moulds and thermophilic actinomycetes (microlyspora faeni) were found in addition to allergens from mice and pollen. Symptoms caused by hay dust were mainly from nose and eyes in people with positive skin tests, but cough, dyspnea and fever were equally common in those with negative skin tests. The most common causes of allergy in farming families were storage mites and cattle, but allergy to cats, dogs and grass pollen were less common rurally than in the Reykjavik area. When comparing individuals working in heavy hay dust with those working in cleaner air, the former group had a higher likelihood of having a positive precipitin test against micropolyspora faeni, fever after work in hay and airway obstruction. It was shown that Icelandic farmers were more likely to get emphysema than other people irrespective of smoking. In a large study of homes in the Reykjavik area almost no mites were found. In spite of this, positive specific IgE tests against dust mites were equally common as in Uppsala, Sweden, where dust mites were found in 16% of homes. In further studies it was found, that 57% of people in the study had been more and less exposed to hay dust. They had either been raised on a farm, been on a farm in the summer during childhood or owned horses and fed them with hay. We have argued that cross allergy to storage mites may be the cause of a rather common allergy to house dust mites. A new study of middle-aged individuals has shown that allergy to storage mites is a little more common in the Reykjavik area than in Aarhus, Bergen or Uppsala. The most likely explanation is that they have more often been exposed to hay dust.