Les actualités sur les pneumopathies d'hypersensibilité en milieu rural

Hypersensitivity pneumonitis (HP) occurring in the rural environment is most often the consequence of exposure to fungi and bacteria. Recently, there have been a number of reports dealing with this problem, most of which fall under the heading of farmer's lung. Some new pathogens have been identified as etiological agents of farmer's lung, based on evidence obtained with serological tests. Environmental and occupational factors associated with the proliferation of these pathogens and with the risk of developing this condition have been identified, or at least suspected of being important. For example, the density of water voles (Arvicola terrestris scherman) appears to be one of the principal predictors of the development of HP. Concerning the diagnosis of these conditions, the results of a large international study provides important evidence on the relative value of clinical and laboratory data, especially for epidemiological studies; these data allow one to limit the use of invasive and expensive examinations. The significance of precipitins and the results of chest HRCT in the differential diagnosis of diffuse infiltrative lung diseases have been defined. Finally, the follow-up of cohorts of farmer's lung has confirmed the frequent evolution of these conditions to obstructive pulmonary disease with emphysema, especially when exposure to the responsible pathogen is not permanent.