Infectious causes and control of acute interstitial pneumonia in feedlot cattle

The cause of feedlot acute interstitial pneumonia (AIP) is not currently kn own, but it is likely that the etiologies vary in different lots or seasons . Infectious agents, particularly bovine respiratory syncytial virus (BRSV) and bacterial pathogens, have been linked to feedlot AIR Bacteria] infecti on in the lung or elsewhere could induce AIP through the effects of the pro inflammatory cytokines tumor necrosis factor (TNF)-alpha and interleukin (I L)-1 beta. Uncontrolled production of TNF-alpha and IL-1 beta is associated with an AIP-like condition in humans, and exposure to bacteria or endotoxi n induces release of these cytokines in cattle. Bacterial infections could thus trigger AIP via a proinflammatory cytokine-dependent pathway. Because the cause of feedlot AIP is unknown, it is not possible to definitively rec ommend mechanisms to control it. However, efforts to control possible cause s are likely to be helpful in selected feedlots.