1、Chapter 9,sporozoa,(孢 子 虫),P58,(疟 原 虫),Plasmodium,Toxoplasma gondii,刚地弓形虫 (弓形虫),Plasmodium(疟 原 虫),Infection of plasmodium cause malaria . Malaria is by far the worlds most important tropical parasitic disease, and kills more people than any other communicable disease except tuberculosis. According t
2、o the WHO report, malaria kills one child every 30 seconds. Malaria is a public health problem today in more than 90 countries; 300-500 million clinical cases each year; more than 90% cases are in sub- saharan Africa Mortality due to malaria case is estimated to be over 1 million death each year.,P5
3、8,Four Plasmodium species are responsible for human malaria :,Plasmodium vivax( 间日疟原虫） P.malariae （三日疟原虫）P.ovale （卵形疟原虫） P.falciparum （恶性疟原虫）,Four species of human malarial parasites are more or less similar in their cycle and morphology.,Human is the intermediate host, the asexual reproduction occu
4、r in liver and RBCs of the human host; Mosquito is the final host, the sexual reproduction takes place in the stomach of mosquito.,Morphology and life cycle,Asexual reproduction in man Development in liver (exo-erythrocytic stage) Development in RBCs (erythrocytic stage) Sexual and asexual reproduct
5、ion in mosquito,Morphology and life cycle,the life cycle of Plasmodium, 红外期(Exo-erythrocytic stage),红外期裂殖子,1、Asexual reproduction in man, 红内期(Erythrocytic stage),红外期裂殖子,大滋养体,未成熟裂殖体,红内期 裂体增殖周期,前进,成熟裂殖体,48h,红内期裂殖子,RBC,间日疟原虫环状体（早期滋养体),细胞核,细胞质,Ring form of Plasmodium vivax,间日疟原虫大滋养体（晚期滋养体),trophozoite o
6、f Plasmodium vivax,间日疟原虫未成熟裂殖体,immature schizont of Plasmodium vivax,间日疟原虫成熟裂殖体,mature schizont of Plasmodium vivax,间日疟原虫配子体,Female gametocyte of Plasmodium vivax,Male gametocyte of Plasmodium vivax,恶性疟原虫早期滋养体（环状体）,Ring form of Plasmodium falciparum,恶性疟原虫（雌雄）配子体,female gametocyte of Plasmodium falci
7、parum,male gametocyte of Plasmodium falciparum,红外期 发育时间,红内期 发育场所,对红细胞 的选择,红内期 发育时间,三种疟原虫人体内发育的比较,2、 Sexual and asexual reproduction in mosquito,Definitive host: Mosquito Intermediate host: Human Infective form: sporozoite (子孢子) Parasiting residence: mainly RBCs Infective way: biting by mosquito , bl
8、ood transfusion.,Conclusion:,潜伏期(incubation period)：,红外期,+,几次红内期裂体增殖,指疟原虫侵入人体到出现临床症状的间隔时间。它包括红外期原虫发育的时间和红内期原虫经几代裂体增殖达到一定数量所需的时间。,Pathogenesis,表现为周期性地寒战、高热和出汗退热。发作周期和红内期裂体增殖周期一致。,发作 (paroxysm)：,由于感染的红细胞被裂殖体胀破后裂殖子和代谢产物、红细胞碎片等共同作用于下丘脑的体温调节中枢而引起寒战、发热。,疟疾初发停止后，患者若无再感染，仅由于体内残存的少量红内期疟原虫在一定条件下重新大量繁殖又引起的疟疾发作
9、。,再燃（recrudescence)：,迟发型子孢子,（relapse):,原因:,直接破坏红细胞,脾功能亢进,免疫病理损害,骨髓造血功能受抑制,贫血（anemia),脾肿大,脑型疟,Duffy血型（-）的西非人对P.v有抵抗力镰状红细胞贫血（HbS）、红细胞缺乏 G6PD对P.f有抵抗力,先天性免疫,immunity,人感染疟原虫后，多能产生一定的免疫力，能抵抗同种疟原虫的再感染，但同时其血液内又有低水平的原虫血症。,带虫免疫,(premunition),免疫逃避,抗原变异,寄生部位,改变宿主的免疫应答性,(immune evasion),检查时间：,恶性疟,发作开始时,间日疟,发作后数小
10、时至10余小时采血,薄血膜涂片法,厚血膜涂片法,血膜染色镜检,Diagnosis,Epidemiology,全球疟疾流行地区主要分布在非洲中部、南亚、东南亚，以及南美北部的热带地区 。,据估算，全球每年约有3.5亿-5亿疟疾病例，其中近100万人死于恶性疟，绝大多数是5岁以下儿童。,86%的病例发生在非洲。北非（埃及、利比亚、阿尔及利亚、突尼斯、摩洛哥）较少，90%的疟疾死亡病例出现在撒哈拉沙漠以南的非洲国家。,9%的病例发生在东南亚。,5%的病例发生在其他地区。,全球90%的疟疾病例为恶性疟，其中75%的恶性疟位于非洲，而91%的死亡病例也发生在非洲。,全球90%的疟疾病例为恶性疟，其中75
11、%的恶性疟位于非洲，而91%的死亡病例也发生在非洲。, 高传播地区,疫情不稳定地区,疫情基本控制区,云南边境及海南山区有恶性疟。从非洲等回国人员中输入性恶性疟和死亡病例逐年增加。2009年疟疾发病数1,4140（间日疟1,0691人,恶性疟1041人，未分型2408.）,外周血中有配子体的病人和带虫者,按蚊叮咬、输血,Epidemiology,source of infection,susceptible population,mode of transmission,根治,预防,控制发作,氯喹、青蒿酯,伯氨喹啉,乙胺嘧啶和伯氨喹啉,抗疟药,Prevention and control,更多精
12、彩详情请观看CCTV-10科教频道 抗疟记或搜索视频抗疟记。,(刚地弓形虫 ),Toxoplasma .gondii,1908年法国学者在刚地梳趾鼠的肝脾单核细胞内发,因其滋养体呈弓形,故名为弓形虫. 1923年捷克眼科医师发现人类首例弓形虫病患儿. 机会致病性原虫(opportunistic protozoan),引起弓形虫病(toxoplasmosis). 先天性感染引起胎儿畸形、流产等,与优生优育密切相关.,P69,对人体致病与传播有关的发育期:,滋养体(trophozoite) 包囊(cyst) 假包囊(Pseudocyst) 卵囊(oocyst),trophozoite of tox
13、oplasma gondii,滋养体,Pseudocyst of toxoplasma gondii,Tachyzoite(速殖子),假包囊,cyst of toxoplasma gondii,包囊,(缓殖子),卵囊,oocyst of toxoplasma gondii,The life cycle of Toxoplasma .gondii includes:,The asexual cycle in intermediate host （human and rodents ）The sexual cycle in the definitive host (cats),The sexual
14、 cycle in the definitive host,Cats gets infected by ingestion of cysts in flesh. Sporozoites , bradyzoites , tachyzoites are released from oocysts , cysts and pseudocysts respectively. Those organisms invade epithelial cells of the small intestine where they undergo an asexual followed by a sexual c
15、ycle and then form oocysts, which are excreted.,The asexual cycle in intermediate host,Human infection may be acquired in several ways:,ingestion of undercooked infected meat containing Toxoplasma cysts; ingestion of the oocyst from fecally contaminated hands or food; organ transplantation or blood
16、transfusion transplacental transmission; accidental inoculation of tachyzoites.,Both oocysts and tissue cysts transform into tachyzoites shortly after ingestion . Tachyzoites localize in neural and muscle tissue and develop into tissue cyst bradyzoites , most commonly in skeletal muscle, myocardium,
17、 and brain; these cysts may remain throughout the life of the host If a pregnant woman becomes infected ,tachyzoites can infect the fetus via the bloodstream .,development in intermediate host,包囊,速殖子,长期存在,破坏宿主细胞, development in definitive host,子孢子,裂殖体,Conclusion,Infective stage :Several stages (pseu
18、docysts, tissue cysts and oocysts ) in life cycle are infective. Definitive host: cats Intermediate host: birds, fishes , human, any mammal Infective ways : infection can be acquired in many different ways. Residence: almost all nucleated cells,pathogenesis,机制,宿主的免疫力,虫株毒力,临床表现,先天性弓形虫病,后天性弓形虫病,常累及脑和眼,流产、早产、畸形等,先天性弓形虫病,无脑儿,先天性弓形虫病,小脑儿,diagnosis,病原学诊断,不易进行,免疫学诊断,主要方法,Endemity,分布,原因,感染阶段具有较强的抵抗力,多种生活史期都具感染性,中间宿主广泛,在宿主之间可相互传播,卵囊可长期生存在中间宿主组织中.,卵囊排放量大,广泛性流行,流行环节,传染源,多样性,传播途径,猫和多种动物,易感人群,均易感,免疫功能低下者尤其易感染,加强对动物的监测和隔离,加强对食品的管理,宣传教育,不吃生肉蛋奶;孕妇不接触猫,治疗病人,磺胺药、阿奇霉素、螺旋霉素,联合用药,Prevention and care,
