<prompt> Parasite causing biliary tract obstruction -AscarisTrichinellaTaenia soliumAll of the above  <response>: Ans. is a i.e., Ascaris Infection of the biliary tract by adult helminths or their ova produces a chronic recurrent pyogenic cholangitis with or without multiple hepatic abscesses, ductal stones or biliary obstruction. The most commonly involved organisms are - Clonorchis sinensis lntrabiliary rupture of hydatid cysts of Echinococcus sp. Intraductal migration of adult Ascaris lumbricoides. Opisthorchis viverrini or O. felineus Fasciola hepatica 