<prompt> All of the following are known to cause biliary obstruction, except:ClonorchisAscarisAnkylostomaFasciola  <response>: Biliary obstruction has been noticed in infection with Clonorchis, Fasciola and Ascaris but not with Ankylostoma duodenale infection. Ref: Harrisons Principles of Internal Medicine, 16th Edition, Pages 1257, 1271 