Lore had it that viruses cause exacerbations of idiopathic pulmonary fibrosis. Wootton et al collected BAL fluid from 43 people during IPF exacerbations. Viruses were present in 4. The exception was “torque teno virus,” present in 12 — but this virus was also present in ~25% of acute lung injury patients’ BALs used as controls. Symptoms in these patients started more than a week earlier, making it at least possible that the exacerbations resulted during convalescence from infection. AJRCCM 2011;183:1698-1702.