Farming practices and the respiratory health risks of swine confinement buildings

This study investigated whether clean swine confinement buildings (SCB) are less harmful to the respiratory system than older and dirtier facilities. Eight healthy volunteers were exposed for 4 h, at 1 week intervals, to eigh t SCB representing the widest possible range of cleanliness, Each volunteer and a technician rated the SCB for cleanliness from 1-10, 1 being the clea nest possible, Airborne dust, bacteria, endotoxin levels, molds, and ammoni a were measured. Fur each volunteer measured, before and after each exposur e, forced expiratory flows (forced expiratory volume in one second (FEV1), and forced vital capacity), white cells in nasal wash and venous blood, and nasal lavage levels of interleukin (1L)-8 and serum levels of IL-6, A meth acholine challenge was obtained at baseline and following each exposure. Cleanliness scores ranged 1.5-8.25. Mean airborne levels were: dust 3.54 mg .m(-3) bacteria 4.25 x 10(5) CFU.m(-3) endotoxins 404 EU.m(-3); molds 883 C FU.m(-3); ammonia 20.7 parts per million (ppm), Expiratory flows decreased after exposure (FEV1 from 4.8+/-0.7 to 4.4+/-0.7, p<0.001), neutrophils in the nasal wash and white blood cells increased (28.5+/-37 to 424+/-207 x 10 (3), 5.4+/-1.0 to 7.4+/-1.7 x 10(9) cells.mL(-1) respectively), IL-8 increa sed from 158+/-311 to 2679+/-639 pg.mL(-1), IL-6 from 0.15+/-0.26 to 2.34+/ -0.92 pg.mL(-1), (p<0.001). All SCB were similarly harmful. In conclusion, modern farming has not succeeded in making swine confinement buildings inoffensive to exposed subjects.