Background and objectives: Several new cases of Extrinsic Allergic Alveolitis or Farmer's Lung (FL) in farm workers were reported to Occupational Health Services in the province of Reggio Emilia (Italy). This prompted the Public Health Department to study the prevalence of the disease among milk-cow breeders involved in Parmigiano-Reggiano cheese production: who are the biggest hay users.
Methods: A suitable questionnaire was sent to 1875 farmers in three of the six districts of the province. Half of them (935: 841 males, 94 females) answered; further contacts and medical history research revealed 33 case of "likely FL". Twenty-three (2 females) (10 "missing"), underwent pulmonary function tests, chest X-rays, precipitins tests against Saccharopolyspora Rectivirgula and other fungal antigens and (22 farmers) bronchoalveolar lavage (BAL).
Results: According to the "Società Italiana di Medicina del Lavoro e di Igiene Industriale" diagnostic standards, we found 20 subjects suffering from FL among farmers collecting hay in large cylindrical (round) bales, dried on field (2.6%) and among others still using small (traditional), prismatic bales (0.5%).
Conclusions: The prevalence on the whole exposed population (6000-9000 people) was estimated between 1.5% and 3.0% (90-270 people); no difference was found in FL prevalence between flat and hilly or mountain areas; the method of collecting hay in big "round" bales, dried on field, seems to produce higher frequencies of FL cases if compared with the traditional ones (more frequent in mountain areas). The new hay packing methods, using forced air driers, are suggested as a possible solution.