We describe two cases of occupational asthma (OA) in workers processing pork meat confirmed by specific inhalation challenges. Animal proteins are a part of the high-molecular weight agents that frequently causes OA (1). In the pork animal, swine confinement facility workers often develop respiratory problems (2, 3) these complaints are less frequent in meat pork-processing plants where the environmental conditions are different. The following report describes two cases of (OA) pork antigen in a meat pork industry.
Both cases were male (33 and 49 years.), atopic and employed in a meat pork-processing plant for 1 and 11 years (subjects A and B) with no previous history of atopy. They were working on the production line, cutting up quarters of pork. After 6 months (subject A) and 11 years (subject B), both developed cough and attacks of wheezing and dyspnea, after starting work on the production line and getting worse at the end of the day. When seen in the clinic, both had been off work for several weeks and almost asymptomatics. Both subjects had a positive skin-prick test (10 and 5 mm) to an extract of pork meat antigen (Hollister-Stier Laboratories, Spokane, WA, USA). Subject A had normal forced expiratory volume (FEV1, 4.85 l) and borderline bronchial responsiveness with PC20 methacholine of 8.65 mg/ml. A bronchial challenge with nebulized pork meat antigen elicited an early response with 30% fall in FEV1 and no change in PC20 (Fig. 1). Subject B had also a normal FEV1 (3.14 l) and mild bronchial hyperresponsiveness (PC20 5 mg/ml). Monitoring of FEV1 at work confirmed the diagnosis of OA with an early response (FEV1 fell by 24% after 45 min of exposition with recovery over 2 h) . Patients were removed from their workplace with improvement in their symptomatology.
Those cases reports show that pork antigen can cause OA through an apparently IgE-mediated mechanism as evidenced by immediate skin reactivity reaction to the diluted pork extract. These subjects also presented symptoms of occupational rhinoconjunctivitis, which is commonly encountered in the case of high-molecular weight agents (4). First case of asthma because of occupational exposure to pigs was reported in 1981 (5). In that case, OA was proved with an inhalation challenge of an extract of pig's urine. PausJenssen and co-workers (6) indeed described an interesting case of OA in a meat pork-processing plant as a result of type-I hypersensitivity and protein contact dermatitis because of type-IV hypersensitivity caused by pork in the same individual. In conclusion pork antigen in workers can give different forms of protein sensitization.