All of the following are known to cause biliary obstruction, except:: (A) Clonorchis, (B) Ascaris, (C) Ankylostoma, (D) Fasciola
Answer is C. Biliary obstruction has been noticed in infection with Clonorchis, Fasciola and Ascaris but not with Ankylostoma duodenale infection. Ref: Harrison's Principles of Internal Medicine, 16th Edition, Pages 1257, 1271