病理學(xué)與病理生理學(xué)：6Human Parasitosis

1、Human parasitosis is a diseases caused by the pathogen of parasites.pSource of infectionproute of transmission psusceptible populationpRegionalpSeasonalpActivity of the natural foci pAmoebiasis is a human parasitosis mostly caused by entamoeba histolytica Intestinal amoebiasis pAmoebic liver abscess

2、 pAmoebic pulmonary abscess pAmoebic cerebral abscess Pathogenesispmechanical injury and phagocytosispContact lysis pCyto-toxicpBacterialpSusceptibilitypImmune suppression and Immune escapeDefinitionParasitic disease, Entamoeba histolytic, trophozoites induce submucosal ulcerations, abdominal pain,

3、diarrhea, strawberry jam-like stool Five species of Entamoeba: E. histolytica (Pathogenic), E. dispar, E. coli, E. hartmanni, E. gingivalis Life cycle : E. histolytica trophozoites cytolytic enzymes and pseudopodia（偽足）（偽足） invade colonic tissue flask-shaped （燒瓶狀）（燒瓶狀）submucosal ulcerations may cause

4、 amoebic liver abscess, bleeding, perforation（穿孔）（穿孔）, peritonitis（腹膜炎）（腹膜炎） Location: firstly involves cecum, colon ascendens, secondly sigmoid colon and rectum, in some cases involve the whole colon and inferior segment of small intestine Characterized by flask shaped ulcer pAcute phasepChronic ph

5、aseGrosspYellowish spotty necrosis/ulcerpSwelling, edema and bleeding zonepMap necrosis, filled with yellowish-brown mucous purulence substanceHistologypliquefaction necrosis, only minor inflammation nearbypLarge amoebic trophozoite can be seen in the juncture of necrosis and normal tissuepvacant sp

6、ace around trophozoiteYellowish spotty necrosis/ulcer flask shaped ulcer Amoebic dysenteryamoebic trophozoite pMixture of fresh and old lesionpNecrosis, ulcer with proliferationpepithelial proliferation and polyppFibrous proliferation, scar, thicken and harden of the enteric wall, stricture of enter

7、ic cavity Amoeba trophozoite penetrate the vein of enteric wallVena mesentericaVena portalis hepatisliver Grossp Single, the size of abscess variedp The fruit jam substance consists of liquification, obsolete bleedingp Abscess wall consists of the connect tissue of vena portalis hepatis, like old co

8、ttonp Minor inflammation around the abscess Histologyp Pus cells, necrosisp Amoeba trophozoite around the wall of abscessp Rare, developed from Amoebic liver abscess, which penetrate the diaphragmatic musclep Most commonly single, often located lower lobe of the right lung, may connect with liver ab

9、scessp The liquification necrosis may be discarded, and the pulmonary cavity formedp Dark brown purulent expectoration, Amoeba trophozoite may be found Schistosomiasis is a parasitic disease caused by trematode flatworms of the genus Schistosoma. Larval forms of the parasites, which are released by

10、freshwater snails, penetrate the skin of people in the water. Etiology and route of infection In the body, the larvae develop into adult Schistosomes, which live in the blood vessels. The females release eggs, some of which are passed out of the body in the urine or faeces. Others are trapped in bod

11、y tissues, causing an immune reaction. At least 230 million people require treatment every year. Schistosomiasis transmission has been documented in 77 countries. However those at most risk of infection are in 52 countries. patients with schistosomiasis pcercarial dermatitis pDamage by the schistoso

12、mulum pDamage by prosopon pDamage by egg pDamage by the antigens and immune compounds in circulation Pathogenesis and morphology Eosinophilic abscessOvumhoeppli phenomenNecrotic tissueCharcot-Leyden crystal eosinophilgranulation tissueAcute ova nodule of schistosomiasisChronic ova nodule of schistos

13、omiasis Calcified ovaLanghans giant cellsEpitheloid cells fibroblasts pseudotubercleColonpAcute phasel Congestion, edema, gray-yellowish or yellow-whitish nodule, 0.54mm in diameterl The nodule may break ulcerl The eggs in the ulcer may be discarded and become pollutionpChronic phasel Eggs calcified

14、, fibrous proliferation, scaringl Ulcer, necrosis, narrowing or obstruction of the enteric cavityLiverpAcute phaselSwelling of liver, not smooth in the surface, numerous millet or mung bean sized yellow or whitish nodules in the surface or the cutting surfacelHistologically, the acute egg tubercle mainly located around portal area, the atrophy, degeneration and focal necrosis of hepatocytes can be seenpChronic phaselEggs calcified, fibro