溶组织内阿米巴课件

,Protozoa introduction,To be defined as unicellular animals； The single cell relatively has complex metabolic activities such as digestion, reproduction, respiration, excretion, etc.10,000 species of parasitic protozoa.Important human parasitic protozoa:Malaria parasites ,Leishmania , Entamoeba histolytica , Trichomonas vaginalis , Trypanosoma and Toxoplasma gondii,Protozoa：,Morphology,1、diversity: round,ellipse, pear shape, irregular,2、Size： very smallRange in size from 2 to more than 200m,1. Plasma membrane:2. Cytoplasm3. Nuclei,Structure,1. Plasma membrane:2. Cytoplasm3. Nuclei,1. Plasma membrane:,a unit membrane,Structure,1. Plasma membrane:2. Cytoplasm3. Nuclei,2. Cytoplasm,ectoplasm: the outer transparent layer. function: protection, locomotion, sensation.2) endoplasm: the inner granular layer, containing vacuoles and organelles. function: metabolism ,nutrition, reproduction.3) organelles:,1. Plasma membrane:2. Cytoplasm3. Nuclei,2. Cytoplasm,3) organelles: A. membrane organelles: Mitochondria, Endoplasmic reticulum, Golgi bodies,etc. B. locomotor organelles : pseudopodia, flagella, cilia.,Structure,1. Plasma membrane:2. Cytoplasm3. Nuclei,3. Nuclei,compact nucleus：seldom2) vesicular nucleus：common,Nuclear membraneA karyosomeChromatin granules,Structure,Physiology,Locomotion:Nutrition:Reproduction:Metabolism:Excretion:,Locomotion:Nutrition:Reproduction:Metabolism:Excretion:,Locomotion: 1) flagella, 2) cilia, 3) pseudopodia, 4) and no specific locomotion organelles.,Trichomonas vaginalis,Physiology,Locomotion:Nutrition:Reproduction:Metabolism:Excretion:,Locomotion: 1) flagella, 2) cilia, 3) pseudopodia, 4) and no specific locomotion organelles.,Balantidium coli,Physiology,Locomotion:Nutrition:Reproduction:Metabolism:Excretion:,Locomotion: 1) flagella, 2) cilia, 3) pseudopodia, 4) and no specific locomotion organelles.,Entamoeba histolytica,Physiology,Locomotion:Nutrition:Reproduction:Metabolism:Excretion:,Locomotion: 1) flagella, 2) cilia, 3) pseudopodia, 4) and no specific locomotion organelles.,plasmodium,Physiology,Locomotion:Nutrition:Reproduction:Metabolism:Excretion:,2. Nutrition 1) permeation: by diffusion or by active transport 2) pinocytosis and phagocytosis:,Physiology,Locomotion:Nutrition:Reproduction:Metabolism:Excretion:,3. Reproduction 1) asexual reproduction 2) sexual reproduction,Physiology,Physiology,Locomotion:Nutrition:Reproduction:Metabolism:Excretion:,3. Reproduction 1) asexual reproduction binary fission: multiple fission: budding reproduction:,Physiology,Locomotion:Nutrition:Reproduction:Metabolism:Excretion:,3. Reproduction 1) asexual reproduction 2) sexual reproduction gametogony: conjugation:,Classification of protozoa,Entamoeba histolytica,E. histolytica lives within the large intestine. Trophozoites can invade the colonic epithelium and produce ulcers and dysentery. This invasive disease can become progressively worse and lead to extraintestinal amebiasis.,Malaria,Schistosomiasis,Amoebiasis,Prevalence of amoebiasis,400 million,200 million,50 million,Morphology 1.Trophozoite,pseudopodium,nucleus,erythrocyte,Chromatic granules,karyosome,Achromatic fibrils,Trophozoite picture by scanning electron microscope,2.Cyst,Stained by Iron hematoxylin,chromatoid body,glycogen vacuole,2.Cyst,Stained by Iodine,Mature cysts,trophozoites,trophozoites,cyst,Life cycle,Be ingested,Be passed in the formed stool,In the lower small intestine, excystation,In the lower colon,Invade the colonic wall,trophozoites,trophozoites,trophozoites,Be passed in the dysenteric feces,Go into the circulatory system,and spread to liver, lung, brain, etc,trophozoites,trophozoites,Summary of life cycle,Infective stage: mature cyst.Infection occurs by the ingestion of cysts in contaminated water, food, or by the fecal-oral route (hands or fomites).Cysts are seen in the formed stool.Trophozoites are seen in the dysenteric feces and liver, lung, brain, etc,Pathogenesis and Manifestation,.10% infected with E. histolytica will develop invasive amebiasis.,?,Factors that determine invasion of amebas:1. Parasite factors A The number of amebas ingested.B The pathogenic capacity of the parasite strain2. Host factors3. Bacteria factors,Possible pathogenic mechanism,Possible pathogenic mechanism,parasite factors1 resistance to host response (eg, complement resistance), to resistance to complement mediated lysis to degrade secretory IgA to suppress T-cell responses to kill neutrophils and other immune effector cells in a contact dependent manner. (lysis of neutrophils could release toxic products which contribute to the destruction of host tissue),Possible pathogenic mechanism,Adherence properties mediated by surface lectin known as Gal / Gal NAC(半乳糖/乙酰氨基半乳糖凝集素)3 Cytolytic properties (adherence + amoebapore) 4 Secrete cytotoxins (cysteine proteinases) and kill target cell in the intestinal mucosa,parasite factors:,Host factors,Possible pathogenic mechanism,Host factors in amoebiasis may be non-immune defense mechanism and specific immunity.,Suitable enteric bacteria can enhance amebic growth.,Bacteria factors,An experiment with cats,Group A Group B,Mature cysts,Mature cysts + Bacillus aerogenes,Lower morbility,Higher morbility,Gentle symptom,Serious symptom,non-invasive . ameba colony on mucosa surface .asymptomatic cyst passer .non-dysenteric diarrhea,Amebiasis Progression,invasive . necrosis of mucosa ulcer .dysentery .hematophagous trophozoites,. ulcer enlargement peritonitis .occasional ameboma . metastasis extraintestinal amebiasis metastasis extraintestinal amebiasis .via blood-stream or direct extension .primarily liver amebic abscess .other sites infrequent .ameba-free stools common,Amebiasis Progression,Amebiasis Progressioninvasive,pathogenesis & manifestation,. ulcer enlargement peritonitis . occasional ameboma,. necrosis of mucosa ulcer .dysentery .hematophagous trophozoites,The places that amebic ulcers occur usually,Caecum87%,Ascending colon 57%,Sigmoid colon 33%,Rectum37%,Pathogenesis,. metastasis extraintestinal amebiasis .via blood-stream or direct extension .primarily liver amebic abscess .other sites infrequent .ameba-free stools common,Amebic liver abscess,Laboratory diagnosis,. Stool examination,. Sigmoidoscopy . Immunological diagnosis. Imaging . Abscess aspiration, Formed stoolsA direct smear stained by Iodine/Iron hematoxylin for cyst.,Compare:,Laboratory diagnosis,. Stool examination, Formed stoolsA direct smear stained by Iodine/Iron hematoxylin for cyst., diarrheic stoolsA direct saline smear for motile trophozoites. 1) fresh stools 2) in time 3) keep warm in cold weather,Laboratory diagnosis,. Stool examination,. Sigmoidoscopy,Lesions, aspirate, biopsy,Laboratory diagnosis,. Stool examination . Sigmoidoscopy,. Immunological diagnosis, Fluorescent antibody The indirect hemagglutination test Indirect fluorescent antibody test,Laboratory diagnosis,. Stool examination . Sigmoidoscopy . Immunological diagnosis,. Imaging,CT, MRI, ultrasound, X-ray,Laboratory diagnosis,. Stool examination . Sigmoidoscopy . Immunological diagnosis. Imaging,. Abscess aspiration,Only select cases,Epidemiology,Distributionall populations throughout the world .the tropics and subtropica than in cooler climates .insanitary communities of temperate and subarctic areas,Epidemiology,Distribution,The incidence is estimated that up to 10% of the worlds population may be infected with either E. histolytica or E. dispar and in many tropical countries the prevalence may approach 50%. There are an estimated 50 million cases of amebiasis per year and up 50 to 100 thousand deaths among them.,Epidemiology,Epidemic factorsReservoir of infection : asymptomatic or only mildly afflicted. The cysts are relatively resistant to bad condition of environment.Disposal of human feces is inadequate, and lead to contamination of food or water with fecal material. The housefly and the cockroach is an importance factor in the transmission of the disease.,Prophylaxis and Treatment,Amebiasis treatment : Asymptomatic: Iodoquinol, Paromomycin, or Diloxanide furoate Nondysenteric, Dysenteric,or Extraintestinal : Metronidazole(甲硝唑,灭滴灵), or Tinidazole+ lumenal agent,Prophylaxis and Treatment,Amebiasis treatment :,2. Sanitary disposal of feces .,3. Protecting water supplies from contamination .,4. Health education in regard to improving personal hygiene, drinking boiled water, hand washing,5. Killing the housefly and the cockroach.,Entamoeba dispar, E. histolytica and E. dispar are actually two morphologically identical species. ( E. histolytica and E. dispar cannot be distinguished on morphological criteria, but DNA sequence and isoenzyme pattern. ), E. dispar is non-pathogenic. ( E. histolytica is pathogenic.),To cause human disease:.Primary amebic meningoencephalitis (PAM) .Chronic granulomatous amebic encephalitis (GAE).Amebic keratitis,Pathogenic free-living amebae,Naegleria,Acanthamoeba,Pathogenic free-living amebae,Naegleria,The portal of entry: the trophozoites enter the nasal cavity, replicating, and then migrate along the olfactory nerves into the brain and CNS.,Pathogenic free-living amebae,Acanthamoeba,The portal of entry: unknown but believed to the either the lungs, skin or eyes. Presumably the trophozoites disseminate by a hematogenous route.,Pathogenic free-living amebae,EntamoebaEntamoeba histolyticaEntamoeba coliEntamoeba disparNaegleriaAcanthamoeba,summary,Mature cysts,trophozoites,trophozoites,cyst,Life cycle