<prompt> Which of the following does not cause biliary tract obstruction ?Ascaris lumbricoidesAnkylostoma duodenaleClonorchis sinensisFasciola hepatia  <response>: Pathogenesis and clinical features of ankylostoma duodanale Infective agent: filariform larvae Poal of entry: skin The worm causes hookworm disease in man characterized mainly by anaemia. refer pgno:144 baveja 3 rd edition 