1、Introduction of ParasitologyZhaojun Wang Ph.D.Rm 512, Bldg 5, 280 S. Chongqing Rd, Shanghai 200025, ChinaTel: 63846590-776460 ; Cell: Email: Objectives掌握寄生蟲與宿主的類型。掌握寄生蟲感染與寄生蟲病的特點。掌握寄生蟲與宿主的相互關系。掌握寄生蟲生活史及其與致病、診斷、流行、防治的關系。熟悉寄生蟲的生物學分類。熟悉寄生現象。熟悉寄生蟲病的診斷方法與應用原則。熟悉寄生蟲病的流行特點與防治原則。了解寄生蟲病的現狀及控制中存在的問題。Medical P

2、arasitologyThe study of pathogenic parasites and their relationships to the hosts and environment. One of the basic sciences of preventive medicine and clinical medicine.Consists of Medical Protozoology（醫學原蟲學）, Medical Heminthology（醫學蠕蟲學） and Medical Entomology（醫學昆蟲學）.Helminthes（蠕蟲）Nematode（線蟲）Trema

3、tode（吸蟲）Cestode（絳蟲）Arthropoda 節肢動物Mosquito (蚊)Fly (蠅)Tick (蜱)Mite (螨)Bug (臭蟲)Flea (蚤)Lice (虱)Medical EntomologyA global problemPlague billions of people, kill millions annually and cause debilitating injuries on additional millions. One person in every four harbors parasitic worms (WHO)Parasitic dis

4、eases6 major unconquered human tropical diseases (WHO)Malaria （瘧疾）Schistosomiasis（血吸蟲病）Filariasis （絲蟲病） Leishmaniasis（利什曼病）Trypanosomiasis（錐蟲病）Leprosy（麻風病）Malaria population is at risk from catch malaria Endemic in 109 countries in 4 continents500 million cases estimated to occur annually1 million r

5、esult in death (children 200 million are estimated to be infected, 120 000 showing symptomsThe second most socioeconomically devastating parasitic diseaseFilariasisElephantiasisLymphatic filariaLoa loadisease River blindness (O. volvulus)Subcutaneous filariaLeishmaniasisAffect an estimated 12 millio

6、n people in 88 countries, and approximately 350 million people are at risk. The self-healing cutaneous form the visceral formTrypanosomiasis錐蟲病African trypanosomiasis (Sleeping disease), 500,000 people in 36 countries are currently infected in Affica Chagas disease, 21,000 deaths per year in Central

7、 and South AmericaHookworm disease (鉤蟲病)7.4 billion infectedAmebiasis (阿米巴病)Infected, 1% world population Annual deaths, 40,000 to 110,000Ascariasis (蛔蟲病)12.21 billion infectedAnnual deaths (intestinal obstruction), 15505 Major Parasitic Diseases in ChinaMalariaSchistosomiasisFilariasis Leishmaniasi

8、sHookworm DiseaseParasites, Parasitism, and host relationsSymbiosis (共生關系)Any organism that spends a portion or all of its life intimately associated with another living organism of a different species is known as symbiont (共生).Such kind of phenomena that two different species of animals “living tog

9、ether” symbiosis. Several types of symbiosisCommensalism (共棲)Mutualism (互利共生)Parasitism (寄生)Commensalism (共棲)“Eating at the same table”Beneficial to one partner and at least not disadvantageous to the other.Remora Fish and SharkMutualism (互利共生)A specialized type of commensalismTwo partners are mutua

10、lly beneficial to each other.Termite and flagellates in its gutParasitism (寄生)Parasitism is a symbiotic relationship in which one animal, the host (宿主), is to some degree injured through the activities of the other animal, the parasite (寄生蟲).Parasite (寄生蟲)Classified according to the physiological de

11、pendence on the hostObligate parasite (專性寄生蟲)For them parasitism is the only life mode and they cannot survive if kept isolated from host. (Plasmodium)Facultative parasite (兼性寄生蟲)For them, either free-living or parasitic life mode could be taken according to the environmental conditions. (Naegleria

12、Spp.)It is implicit in this term that the organism does not of necessity have to be a parasite at any stage of its existence.Classified according to the parasitic locationEndoparasite (體內寄生蟲)Lives within the body of hostEctoparasite (體外寄生蟲)Lives on the surface of the body of hostHost (宿主)Definitive

13、host or final host (終宿主)The host in which the adult stage or sexual stage of the parasite develops. Intermediate host (中間宿主)They provide living of larvae or asexual stages of the parasite.Reservoir host (保蟲宿主)Reservoir host is an animal which harbors parasites in nature and acts as a source of infec

14、tion.Paratenic host (轉續宿主)A host which acts as a transporting agent for the parasite and in which the parasite does not undergo any development is called paratenic host.Life Cycle (生活史)Main topic of the parasite biologyLife cycleThe life cycle is the obligatory of parasites for their growth, transfo

15、rmation and multiplication that may be plished in their host (or hosts) or environment.Stage in environment (vector)Stage in manInfective stageStage left manLife CycleMouthSkinInsect inoculationContactStoolUrineSputumVectorInfective stage (感染期)A stage of parasite which can enter the human body and d

16、evelop continuously there.Pathogenicity, treatment and diagnosisEtiologicaldiagnosisEpidemiology and prophylaxisPreventionLife cycle of Fasciolopsis buskiAdaptations to ParasitismMorphologic adaptationsChange of the shape and figure to adapt the site of living within the host.Organs of otion, and th

17、e digestive system may be degenerated in various degree or even disappear.The reproductive system is very highly developed in the trematodes and cestodes.Specialized attachment organs have been developed by the flatworms.Physiological adaptationsDevelop specialized mechanisms for effecting entrance

18、into the body or tissue.Successfully e the immune response of the hostLocate in relatively protected sitesChanges in the parasite surface antigenic structureModify the host immune response by products of parasite metabolism Increase reproductive capacityPenetration glandsEffects of the Parasite on t

19、he HostInjury to the host may be brought about in many ways.Deprive essential substances of the host.Invasion and destruction of host tissue.Chemical (toxic) actionImmunopathogenesis (Parasite exert harmful actions to the host and cause injury)Deprive essential substances of the hostHookworms in sma

20、ll intestineInvasion and destruction of host tissueCysticercosis of the skeletal muscleCerebral cysticercosis Chemical (toxic) actionAmoebic abscessImmunopathogenesisCutaneous larva migransSchistosome egg granulomaParasite infection and parasitic disease.Overt symptoms of infection may depend on the

21、 number of worms present, the nutritional status of the host, or both.Innate immunityAcquired immunityCan be demonstrated in many parasitic disease.Absolute immunity to reinfection is rarely following protozoal infections and probably never with helminth infection. Just resists to hyperinfection.Pre

22、muniton in malaria itant immunity in schistosomiasisEffects of the Host on the parasiteEPEDIMOLOGY AND CONTROLThree links in the chain of the parasitic diseases transmissionSource of infectionRoute (mode) of infectionSusceptible populationSource of infectionThose animal or human host that continuously excreting or maintaining certain stage of th