并殖吸虫病ppt课件_3.ppt

乙方有义务提供相应的执业资格证、执业印章等配合甲方工程招投标、承担的工程项目报建及建设施工过程中各类手续办理。 Paragonimiasis Intruduction A kind of chronic disease caused by paragonimus westermani, paragonimus szechuanensis and several other related species Adult worm of paragonimus westermani inhabit lungs of the final host, causing cough, chest pain, rusty sputum and hemoptysis paragonimus szechuanensis cause subcutaneous nodules and masses Infected by eating raw crayfish and freshwater crab Etiology Morphology Adult worm: they are monoecious, the reproductive organs are parallel, have two suckers Eggs: golden brown, ovate, operculate, the size is 80-120×48-60?m Metacercariae: round or ovate. Diameter 300-400 ?m, 1-3 layers of cyst wall Life Cycle Man with adult worm to mature passing eggs into water 2-3months 21 days eating miracidi Metacercaria first intermediate host(special snail) second intermediate host 3 months (crayfish and freshwater crab) cercaria Epidemiology Source of infection: humans mammals and other worm carriers, which can produce eggs Route of transmission: 1.The presence of the final host:patients and the infected mammals 2.The presence of a large amount of 1st and 2nd intermediate host 3.The habit of eating the freshwater crayfish and crab Susceptibility: every one is susceptive Character of Epidemic Widely distributed: Asia, Africa, America in our country, more than 21 provinces are involved in the infection It mainly occurs in summer and autumn North:the type of crayfish epidemic South:the type of freshwater crab epidemic Pathogenesis and Pathogen Process Caused by Juvenile Worms Metacercariae excyst in duodenum, and into abdominal cavity, the migrate cause mechanical lesions Penetrate diaphragms into pleural cavity to cause lung cy