<prompt> A 35 years old man presented with dry cough and rusty coloured sputum; He has history of eating in chinese restraunt very often with consumption of crabs often; What is the probable causative agent in this condition?Diphyllobothrium latumPneumocystis jiroveciiParagonimus westermaniStrongyloides stercoralis  <response>: from above mentioned clinical scenerion Paragonimus westermani lung fluke is moste likely to be causitive organism:- Paragonimus westermani first intermediate host- snail 2nd intermediate host - crab in crab metacercarie larva which is cyst like stage is seen. It causes Red Brown sputum or endemic hemoptysis. 