Reveal the darkest side of the insect world They hide in the dark, predators, and human struggle of millions of years. They coveted our body, not only taking the blood of the living and the dead body ... ... swallow Bloodsucking insects almost conquered all the Earth's ecosystem, including us humans. Now, scientists will take you to understand the darkest side of the insect world. With the world's largest, most disgusting, the most deadly insect face. Intrusion cone hunting bugs Many people believe that it killed Darwin It is creeping in the darkness, piercing the skin of the sleeping person, stealing blood. It used to be the dissemination of a bloodthirsty parasites, causing a fatal disease --- Chagas disease. Intrusion cone hunting bugs can quietly sneak into the bloodstream, it can be parasitic in the human body for decades, the organ gradually weakened until it collapsed. Biologist Charles Darwin would have been intrusive cone hunting bugs bite, some people believe he died of Chagas disease. Central and South America almost 18 million people suffering from Chagas disease. This disease has no vaccine, no cure. Intrusive bugs hunting cone 200 can be slightly mad suck blood. Expansion of the stomach to eat so that they can hold the equivalent of three times the weight of the blood. However, their behavior after eating, is the real cause of disease transmission --- defecation. This worm infected with parasites in excreta. Itching, the parasites will enter the wound --- cause Chagas disease.
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No. 2
Reveal the darkest side of the insect world They hide in the dark, predators, and human struggle of millions of years. They coveted our body, not only taking the blood of the living and the dead body ... ... swallow Bloodsucking insects almost conquered all the Earth's ecosystem, including us humans. Now, scientists will take you to understand the darkest side of the insect world. With the world's largest, most disgusting, the most deadly insect face. Intrusion cone hunting bugs Many people believe that it killed Darwin It is creeping in the darkness, piercing the skin of the sleeping person, stealing blood. It used to be the dissemination of a bloodthirsty parasites, causing a fatal disease --- Chagas disease. Intrusion cone hunting bugs can quietly sneak into the bloodstream, it can be parasitic in the human body for decades, the organ gradually weakened until it collapsed. Biologist Charles Darwin would have been intrusive cone hunting bugs bite, some people believe he died of Chagas disease. Central and South America almost 18 million people suffering from Chagas disease. Today there are vaccines to cure, the skin discomfort immediately after throughout the body looking for blood-sucking insects and immediately out of the domestic outdoor supplies may have to buy household appliances in Europe to buy is a smear, anyway, faster, and then go to the hospital to check the body, immediately accept any abnormalities related to treatment. Intrusive bugs hunting cone 200 can be slightly mad suck blood. Expansion of the stomach to eat so that they can hold the equivalent of three times the weight of the blood. However, their behavior after eating, is the real cause of disease transmission --- defecation. This worm infected with parasites in excreta. Itching, the parasites will enter the wound --- cause Chagas disease. Schistosomiasis is a parasitic How? The scientific name is schistosome flukes, parasitic insect species are important human S. japonicum, Schistosoma mansoni, Aishi Mekong schistosomiasis and schistosomiasis. Schistosoma japonicum in China only, and its dioecious. Chunky male, average body length 16mm, milky white. Female slender, slim front, the average body length of 20mm, the rear due to intestinal parasites digest hemoglobin and is filled with dark brown; females often hold the female in the male of the trench, was to encircle the state, both encircle the parasitic in the human and reservoir cattle, sheep, pigs, rats, rabbits and other mammals, the hepatic portal vein and superior mesenteric vein system. Surface of some or all of the adult sexes have small nodules or spine-like protrusions, mouth and ventral sucker is located in front of parasites, parasites in the vein wall by suction cups adsorption, through the mouth and the ventral sucker of a reverse flow from creeping smoking a migration to the intestinal submucosa of the peripheral veins, where mating spawning, egg-shaped oval, yellow, eggs containing miracidia. Substances secreted by miracidia egg shell dissolve the organization, leading to vessel wall damage surrounding tissue inflammation, necrosis, and stimulate bowel movements to strengthen, causing intra-abdominal pressure, blood pressure changes, some of the eggs with the necrotic tissue to the intestine ulceration, mixed in fecal excretion host body, in contact with water in 25 ℃ ~ 30 ℃ under the conditions of hatched miracidia, miracidia floating in the water, case of intermediate host snails, the invasive snail body is active, the mother sporocyst, sub-series of sporocyst growth and proliferation, and finally the tail fork have formed a number of cercariae, snails stages escape the body, often floating on the water. Cercariae of Schistosoma infection stage, when human and animal contact with contaminated water, the cercariae to the mouth, ventral sucker attached to the skin, puncture gland secretion of soluble substances dissolve skin tissue proteases, and quickly penetrated the skin off the tail into schistosomula. Schistosomula through the capillaries into the venous or lymphatic vessels, with the blood flow through the right heart, lung, left heart into the systemic circulation, some of them to the superior mesenteric vein, with blood flow to the intrahepatic portal venous system migration branch, develop into adults and then retrograde into the superior mesenteric vein in the _set_tlement. Cercariae invade the host 24 days after the females start laying eggs, a female about 1,000 eggs a day, five weeks after the host eggs in feces can occur. Schistosomiasis in the human body can survive for up to 30 or 40 years. Schistosome infection in the body how? Schistosome infected with the human need to have three conditions, namely, the source of infection, transmission and susceptible populations. (1) The source of infection: schistosomiasis is the exchange of human and animal parasites. More of its reservoir host species, mainly cattle, pigs, dogs, sheep, horses, cats and rodents and other 30 kinds of animals. Patients and sick cattle as the main source of infection, and secondly, for the infected sheep, pigs, dogs, horses, rodents, etc. Long time no livestock activities in some areas, schistosomiasis by snails in the spread between wild animals, the formation of primary foci; activities in the _set_tlements or livestock production areas, posed by the spread of snail foci are times on_set_ foci. (2) The source of infection of the snail manure into a contaminated water exists, the host and spread through contact with contaminated water. ① feces into the water: fecal contamination of water ways, as the production of local residents, living habits and feeding livestock management methods vary. River wash the toilet, anywhere in the stool, application of fresh manure and cattle grazing and other particularly vulnerable to pollution of water sources. ② there snails: snail is the only intermediate host of schistosomiasis, it is limited to areas with snails, be possible to have schistosomiasis epidemic. In China, schistosomiasis popular in the Yangtze River, and south of the 12 provinces, autonomous regions and Shanghai and the Yangtze River region is more serious. After years of prevention, the epidemic has been basically brought under control. Snail infection rate and water pollution is closely related to the use of sentinel snails ways to measure water pollution. Distributed in China's Hubei Province, said the snail snails, there are seven subspecies. Snails are mollusks, amphibious, multi-breed in sufficient water, rich in organic matter, weeds, moist shaded shallow irrigation ditch or river; usually live in the water line up and down, with winter temperatures drop a few centimeters deep under the ground dormant winter. Snails in the ground, but limited range, slow. However, the snails can be attached to the surface of floating objects, such as lake grass, reeds, boats, etc. spread to a distance, or to expand the scope of the original breed to form a new breeding ground. ③ contact with contaminated water: In endemic areas, residents living and production activities for a variety of contact with contaminated water and infection, as usual due to fishing, playing compost grass, swimming, washing things, feet and other contact with contaminated water can also be due to barefoot containing cercariae walking on the ground, cercariae penetrated the skin. Number of cercariae invade and water pollution, the skin area exposed, time and frequency of contact with contaminated water is proportional to. In addition to the skin, the cercariae can also drink unboiled water intrusion from the oral mucosa in vivo. (3) susceptible population: generally susceptible to infection with the local residents rate is proportional to the infected snails. Patients with fishermen, farmers and more, especially young adults aged 15 to 30 due to repeated contact with contaminated water and infection rate is higher. More men than women, infection is most common in summer and autumn. Children and non-endemic areas suffer from a large number of infected people may soon have some resistance, tolerance of re-infection is not complete, so repeat infections occur frequently. How to make the incidence of schistosomiasis? Since the cercariae penetrate the skin, the schistosomula migrate and develop into adult, mature adult mating spawning, eggs deposited in the gut and liver tissues, etc., four developmental stages of schistosome life cycle in the human body can cause damage, but The first three are caused by disease, or transient, or minor, are enough to cause significant damage to the human body. CD egg deposition in the tissue reaction induced by egg granuloma but the basic pathology of the disease. (1) cercaria dermatitis: generally occurs at 6 to 8 hours after infection, the elderly 2 to 3 days. Cercariae penetrate the skin, its head gland secretion of enzymes and dissolved the organization after the death of the collapse of the product itself, can cause local skin telangiectasia, congestion, hemorrhage and edema, with neutral and eosinophils and tissue cells infiltration, red skin rash, a "cercaria dermatitis." By the rapid on_set_ and delayed type hypersensitivity due. 1 to 2 days, pimples subside on their own. (2) lesions caused by migrating schistosomula: schistosomula migration along the blood flow, can cause organ through the Department of lesions, lung lesions with more obvious, visible spotting and local leukocyte infiltration, severe infection may occur hemorrhagic pneumonia, cough, fever, urticaria, and blood eosinophils increased, such as performance, this metabolite with parasites or allergy caused by the collapse of matter. (3) adult parasites cause lesions: Experiments show that adults and their metabolites produced only a slight vein of local meningitis, mild anemia and increased eosinophils. After the death of parasites, although the vessel wall can cause necrosis and intrahepatic portal vein thrombosis vasculitis, but mild, not to cause serious damage. Mature female eggs are laid, some of the first severe infection may occur with severe fever, malaise, urticaria, abdominal pain, diarrhea, hepatosplenomegaly, increased eosinophils, such as the performance of acute schistosomiasis, which may belong to immune complexes material type. (4) egg granuloma: In addition to eggs deposited in the rectum, sigmoid, ascending colon, appendix, ileum and liver, can still be found in the mesenteric and retroperitoneal lymph nodes, lungs and brain and other organs. Eggs deposited in different parts of the pathological changes caused by similar, which is divided into acute and chronic. Intestinal lesions caused by schistosomiasis are generally located in the inferior mesenteric vein within the colon, especially in the rectum, descending colon and sigmoid colon as a significant, small intestine lesions rarely, only in severe patients. Acute phase showed mucosal swelling, was acute catarrhal inflammation, with scattered superficial punctate bleeding and small ulcers. Microscopically, the mucosa and submucosa egg granuloma (acute phase). Mucosal necrosis, the formation of superficial ulcers, eggs which fall into the intestine. Clinically, abdominal pain, diarrhea, blood in the stool and other symptoms, can be detected in fecal egg. To chronic, mild infections, mild proliferation of connective tissue of its wall, usually clinically asymptomatic. The heavier the infection, the disease is more extensive involvement of the colon was thickened, granular mucosal hyperplasia, or even the formation of polyps; or mucosal atrophy, mucosal folds disappear. Mucosal proliferation and atrophy in the room, dirty gray mixed with a small shallow ulcers. In addition, a small amount of sallow acute egg still visible nodules. Severe chronic schistosomiasis, the colon wall by diffuse fibrosis and extensive thickening of the lesion fibrous thickening of the mesentery also see the two together to form lumps. Because repeated infections, females continue to lay eggs, egg batches deposited in the intestinal wall, mixed old and new lesions. In the fiber thickening, chronic ulcers, polyps on the basis of the formation of cancer may occur. Schistosomiasis caused by liver disease, as early hepatomegaly, yellow miliary visible on the surface particles (eggs nodules). Late around a lot due to portal vein fibrosis, liver hardening, narrowing, surface nodules form of schistosomiasis cirrhosis, portal establishment of collateral circulation to the lower esophageal veins and varices, spleen due to enlargement of portal hypertension and congestion, can cause hypersplenism. Ectopic schistosomiasis caused by damage to the most common lung and brain, lung nodules shows miliary nodules and exudative inflammation around the brain can occur at different times of the eggs nodules and gliosis. References: Anti-schistosomiasis drug Praziquantel Praziquantel for the isoquinoline pyrazine derivatives, as broad-spectrum anti-fluke drugs and taeniafuge drugs, particularly the role of schistosomiasis have to kill attention. Of nematodes and protozoa infection is invalid. [Insect] role In addition to schistosomiasis with praziquantel kill, but on the other trematodes, such as clonorchiasis, ginger fluke, Paragonimus, and a variety of tapeworm infections and their larvae cause the disease cysticercosis, echinococcosis varying degrees effect. This chapter focuses on the role of its anti-schistosome; other anti-intestinal worms, the role and purpose. In in vitro experiments, the rapid uptake of praziquantel for schistosomiasis. At the lowest effective concentration (0.2 ~ 1.0μg/ml), the parasites can excitement, contractions and spasms. Slightly higher concentration, will enable the schistosome body cavity and ulceration were formed, infiltration of granulocytes and macrophages, and finally to parasite death. Overall results show that within minutes after treatment, 95% of the mesenteric vein to the liver schistosomiasis, and death in the liver. These effects of praziquantel may be related to increased body is the permeability of Ca2 +, Ca2 + interfere with the body balance is closely related to insects. Remove the culture medium by adding Ca2 + or Mg2 +, you can cancel the effect. As the occurrence of spastic paralysis of the worm, so that it can not be attached to the vessel wall, blood flow into the liver is that the liver shift. In the liver was due to lack of complete protection of the whole, more easily eliminated by phagocytic cells. Praziquantel had no such effect on the mammalian cell membrane, thus showing the role of highly _select_ive. [Process] in vivo Rapidly and completely absorbed orally with praziquantel, in 1 to 2 hours after taking up to peak plasma concentration. As the first of the elimination of many, limiting its bioavailability. Hydroxylation in the liver mainly inactivated by renal excretion. Discharged within 24 hours the dosage of 90%. By renal excretion as unchanged drug dosage of not to exceed 0.02. Eliminate the t1 / 2 healthy persons 1 to 1.5 hours of advanced schistosomiasis patients was significantly Director. [Clinical effects] Chronic schistosomiasis japonica, 20mg/kg, three times a day, day treatment, or 10mg/kg, three times a day, once every 2 days, long-term cure rate of up to 90%. Acute schistosomiasis, a rapid improvement of systemic symptoms of fever and the role of long-term effects are up to 87%. Heart, liver and other complications in patients with advanced multiple successful completion of treatment. Adverse reactions Side effects are mild, short-lived. Can occur shortly after taking abdominal discomfort, abdominal pain, nausea, and dizziness, headache, muscle bundle fibrillation and so on. ECG changes appear small. Schistosomiasis Schistosomiasis, also known as flukes (Schistosoma). Schistosome species parasitic on the body's more, there are three, namely, Schistosoma japonicum (S.japonicum), Schistosoma mansoni (S.mansoni) and Egypt schistosomiasis (S.haematobium). In addition, in some local areas there intercalatum schistosomiasis (S.intercalatum), Mekong schistosomiasis (S.mekongi) and Malay schistosomes (S.malayensis) parasites in the human case report. Schistosoma distributed in Asia, Africa and Latin America 76 countries and regions, an estimated 5 to 6 million people at risk, the number of patients up to 200 million (1990). Schistosoma japonicum in China is only that we usually refer to schistosomiasis. Mummy body from the Western Han Dynasty, Hubei Jiangling schistosome eggs seized the fact that the presence of schistosomiasis in China at least 2100 years of history. Schistosome parasites in the body in the morphology, physiology and life history, etc., unlike many other human parasitic flukes, such as schistosomiasis Department of dioecious; adults in the superior mesenteric vein or venous plexus of bladder parasite, eggs from the feces or urine, because insect species vary; forked tail cercariae in the water penetrated through the skin shrink the primary; life history in a mine-free larvae and metacercariae stage. Have to S. japonicum, for example, a more detailed description, and briefly referred Shaoman Shi and Egyptian Schistosoma japonicum. A Schistosoma japonicum Schistosoma japonicum located in the Western Pacific Region of China, Japan, the Philippines and Indonesia. In China, the distribution of schistosomiasis in the south of the Yangtze River and its 12 provinces, municipalities and autonomous regions. Taiwan Schistosoma japonicum infection in animals, but no human cases. Generally believed that several major human schistosomiasis, the disease caused by Schistosoma japonicum infection in the most important, control the most difficult. This is because many animal hosts of Schistosoma japonicum; adult life long; immunization and after infection with poor immunity after cure; difficult to control the snail intermediate host. Endemic area of schistosomiasis, according to the geographical distribution of snails and epidemiological characteristics, water network model is divided into plains, mountains and lakes hills type type. Form 1. Adult male and female variants. White male, long 12 ~ 20mm, C1l parasites flat, front-end have developed the oral sucker and ventral sucker, ventral sucker below parasites extended to both sides, and slightly to the ventral curl to form a holding female groove (gynecophoral canal), Therefore, cylinder-shaped appearance. After the coarse before fine females, the shape of nematodes, body length 20 ~ 25mm, ventral sucker larger than oral sucker, the intestinal digestion of the full blood or half-digested, so the female is dark brown, often hold female residence in the trench, and the male encircle insects (Figure 14-16). Mature females must have the presence of male and encircle, to promote growth and development of female substance may be from a male sex pheromone (pheromone), through the encirclement, the wall pass from male to female worms, the other male and female sexual contact is to promote nutrition a major factor in their development. Generally believed that single-sex female sexual maturity can not be developed; and can produce single-sex activities, although the male sperm can mature, but more time was needed, shape is also smaller. Figure 14-16 adult S. japonicum Digestive system are the mouth, esophagus, intestine. Intestine is divided into the two anterior dorsal ventral sucker, extends back to the parasites back 1 / 3 merge into blind tube. Adult blood feeding, digestion and bowel is filled with hemoglobin, was black. Intestinal contents through the mouth can be released into the blood circulation within the host. In the male reproductive system by the testes, seminal vesicle, gonopore composition. Testis is oval, usually seven, were arranged in a single row, in the dorsal ventral sucker. Gonopore opening in the abdominal sucker below. Female reproductive system by the ovaries, eggs gland, egg mold, plum gland, uterus and other components. Ovarian parasite in the middle of a long oval. Oviduct from the ovary back, around the ovaries and forward. Parasites back almost filled yolk gland, yolk tube extending forward, and fallopian tubes merge into egg mold, and surrounded by plum gland. Eggs die and connecting the uterus, uterine opening in the abdomen below the sucker, containing 50 to 300 eggs (Figure 14-16). 2. The average size of mature eggs egg 89 × 67μm, oval, yellow, egg shell thickness and egg-free cover, egg shell side of a small spines, often with the host tissue surface residues, thin egg shells underneath the embryo membrane. Mature egg contains a miracidium, miracidia and egg shells of varying sizes between the often circular or oval-shaped head gland secretion droplets (Figure 14-17). Electron microscopy, egg shell surface was fine mesh granular micro-fiber matrix and spine; egg shell section shows cystic microchannels, through internal and external egg, miracidium soluble antigens secreted by the egg shell may be cystic release of eggs outside the microchannel. In the feces, the eggs contain miracidia is the most mature eggs, immature and atrophic eggs in the minority. 3. Miracidia was pear-shaped or long oval, symmetrical, the average size of 99 × 35μm, the whole body is ciliated, is the active organ. Diamond is located on the front of the body was mouth-like protuberances, or rostellum; the front of the body has a top central gland, is a pocket structure; two side of the gland or glands, said head gland is located in the top later on both sides, elongated pear shape, and they are open to drilling, or rostellum (Figure 14-17). 4. Schistosome cercariae are fork-tailed cercariae, formed by the body and tail, the tail end of another sub-dry and fork. Body length 100 ~ 150μm, dry tail length 140 ~ 160μm, fork length 50 ~ 70μm (Figure 14-17). Body surface is a small spine and with many single papillary sensory cilia. Specialized body to the head end device (head organ), the first device in the center there is a large single-celled glands, known as the head gland. Before the correct port is located in the ventral body, ventral sucker in the body after 1 / 3, by the well-developed muscle structure, has a strong adsorption capacity. Cercariae in the body in the back of five-on-one drill gland cell (penetration gland), symmetrical arrangement, of which two pairs of ventral sucker in the front, said before the drill gland, as eosinophils, containing coarse particles; three pairs of ventral sucker is located after the , said after the drill gland, as basophilic, containing fine particles. Before and after the five pairs of diamond by five pairs of tubular gland to the body at about two-beam front stretching from the first device, and opening at the top (Figure 14-17). Figure 14-17 and the stage larvae of Schistosoma japonicum eggs Life history and developmental phases of biology Schistosoma japonicum is more complex life cycle, including in the final host body and the sexual generation in the body of the snail intermediate host asexual generations alternate. Sub-adult life history, eggs, miracidia, mother sporocyst, sub-sporocyst, cercariae, schistosomula of seven stages (Figure 14-18). Adult S. japonicum parasites in the human and various mammalian portal - mesenteric venous system. Females lay eggs in the peripheral vein, the eggs mainly in the liver and colon wall tissue, eggs mature, the eggs fall off into the intestinal lumen containing miracidia, excreted with the feces. Faecal contamination of water with eggs, and in the appropriate conditions, the eggs hatched miracidia. Miracidia in the water met the appropriate intermediate host snails, snails invade the body and gradually developed. The formation of pocket before the mother sporocyst, the body of the embryo cells can produce a number of sub-sporocyst, sub-sporocyst escape into the snail liver, the body of another germ cell proliferation, the formation of many batches of cercariae. Mature cercariae leave the snail, often located in the surface water, human or animal with water containing cercariae contact, cercariae through the skin and infections. Cercariae penetrated the skin, take off the tail, develop into schistosomula. Schistosomula penetration of small veins or lymphatic vessels, with the blood or lymph to the right heart, lung, small blood vessels through the alveoli into the left heart and transported to the body. Most children re-entering the small veins insects, the blood flows along the branches of the intrahepatic portal system, schistosomula a temporary stay in this, and continue to develop. When the initial differentiation of sexual organs, the encounter began to encircle the opposite sex schistosomula and migrate to the portal - mesenteric vein as an alien, and gradually mature mating spawning (Figure 14-18). Figure 14-18 Schistosoma japonicum life cycle 1. Oviposition and egg excretion of adult parasites in the definitive host of the portal, mesenteric venous system, the parasites migrate to the intestinal submucosa reversible flow of small peripheral veins, encircle the mating male and female adults lay their eggs here, each female Daily about 300 to 3000 eggs. Schistosoma japonicum female ovulation time in paroxysmal discharges to clusters, so that the eggs in the host liver and intestinal tissue blood vessels are often deposited into a rosary-like, female fecundity due to insect strains (strains), experimental animal hosts and insect parasitic body length of time varies. Most eggs produced by deposition in small blood vessels in the intestinal wall, with a small amount of blood into the liver. After about 11 days, the eggs develop into miracidia within the egg, miracidium-containing eggs mature in the organization can survive for 10 days. Since miracidia secretions through egg shells, destroy the vessel wall, and to the surrounding tissue inflammation necrosis; while intestinal motility, increased intra-abdominal pressure, resulting in necrotic tissue to the intestine ulceration, eggs will immediately fall into the intestinal tissue ulceration cavity, excreted with the feces. Eggs can not be deposited in the discharge of local organizations, and gradually died, calcification. 2. Miracidium hatching eggs containing water contaminated with the stool, and in the appropriate conditions, the eggs hatched miracidia. The miracidia hatch and temperature, osmotic pressure, light and other factors. When the temperature is between 5 ~ 35 ℃ can hatch, generally the higher the temperature, hatching sooner, miracidia of the shorter life expectancy to 25 ~ 30 ℃ most appropriate; low osmotic pressure of the water, light irradiation can accelerate the miracidium of incubation; pH of the water is also very important, eggs miracidia of the most suitable pH of 7.5 to 7.8. Miracidium after hatching, are located in the surface water body, in a straight line, and there phototropism and to clear features. Miracidia in the water can survive 1 to 3 days, the longer the elapsed time after hatching, the lower the ability of infected snails. When confronted with the snail intermediate host, the active intrusion, for asexual reproduction in the snail body. 3. Development of larvae in the snail breeding snail body is the only intermediate host of Schistosoma japonicum. Miracidium snail attacks and soft tissue absorption is due to adsorption of the front-end drilling device and a contralateral gland secretion of mucus the result; At the same time, miracidia top gland cells secrete proteases to degrade glycoproteins containing extracellular matrix components, to facilitate the drilling Lo wearing soft tissue. With it, miracidia constantly alternating stretching movements, and from the dissolved into the soft tissues, miracidia surface cilia loss, embryo cell division, two days after the first foot in the snails and develop into organs, etc. mother sporocyst begin. Produced by the body in the mother sporocyst germ cells, germ cells and multiply each child into a sporocyst, the young child has a cell motility, broken out migration to the liver parasitic snails. Sub-sporocyst slender, segmental, embryonic cells and divided the body and gradually develop into many cercariae. A miracidium snails drill into the body through asexual reproduction, resulting in tens of millions of cercariae, in batches mature cercariae in the snail body, one after another escape. Cercariae to form the whole process time and temperature, at least 44 days and the longest was 159 days. Mature cercariae escape from the snail body and active in the water swimming. 4. Escape and impact of invasive cercariae cercariae from snails escape host of factors, the most important factor is water temperature, usually in the range of 15 ~ 35 ℃ no different, the most suitable temperature for 20 ~ 25 ℃; light escape of cercariae have good effect; water pH in the range of 6.6 to 7.8, the cercariae escape unaffected. After the cercariae escape, mainly in the underwater, its life is generally 1 to 3 days. Cercariae and their survival time with the ambient temperature and the water appeal of the nature and length of time after escaping cercariae varies. When cercariae encountered when the human or animal skin with suction cups on the skin absorption, relying on the secretion of glandular cells in vivo enzymatic role, the role of head of exploration stretching device, and parasites muscles coordinated movement of the mechanical role of the host to complete drilling skin. Can be penetrated in minutes. Once the cercariae penetrated the skin after the discarded tail. Generally believed that, after drilling gland glycoprotein secretion of water swelling into a viscous jelly, to the skin adhesive, to facilitate drilling gland secretion of the enzyme before the orientation and to avoid the loss of enzymes and other effects; gland secretions in the previous drilling protease activated by calcium ions, can soften the keratin, and degradation of interstitial cells of skin epidermis, basement membrane and dermal matrix, etc. will help cercariae penetrate the skin. 5. Skin worms off the tail cercariae _set_tle and nutrition, skin invasion of the host, called schistosomula (schistosomula) schistosomula after a short stay in the subcutaneous tissue, invasion of the small peripheral blood vessels or lymphatic vessels, with the blood flow through the right heart to the lungs, and then left heart into a large circle, to reach the upper and lower mesenteric artery, through the capillaries into the portal vein, to be developed to a certain extent, male and female adults to encircle and then migrate to the mesenteric veins and hemorrhoidal veins dwelling, mate, lay eggs. Since cercariae invade the host to mature adults and begin to lay eggs about 24 days, the output of eggs mature within the organization to be about 11 days. Time in human adults living memory varies due to insect species, the average adult life expectancy in Japan suck the blood of about 4.5 years, can live up to 40 years. Schistosome growth and development of nutrients from the host, which has two absorbing material interface, the body wall and intestinal absorption of nutrients are the functions, and each interface on the _select_ive absorption of the material. Absorption and exchange of body wall bears and other important physiological functions, the current intake of simple sugars that the body primarily through the intestinal wall and not, and still capable of absorbing media in a number of amino acids. Schistosome nutrition is another way gut, the parasite constantly through the mouth and swallowed the host red blood cells, red blood cell uptake estimated number of females per 330 000 / hour, while the male is only 3.9 million / hour. Red blood cells are the body of the insect digestive proteolytic enzymes. Female than male high enzyme activity, red blood cells to provide nutrients to the α and β chains of hemoglobin after digestion produces peptides or free amino acids; and nucleotides from red blood cells to the nucleoside. Remaining red blood cells were digested in the intestine of brown melanin is a complex porphyrin material, due to schistosomiasis no anal hole, so pigment residue from the discharge port. Pathogenic Different stages of schistosome development, cercariae, schistosomula, adults and eggs can cause different damage to the host and the complexity of the immune pathological response. Since the different phases of the causative agent, host involvement of tissues, organs and body reaction are different, causing the disease and also have the appropriate clinical features and stage. According to the nature of the cause of immune pathology, it was advocated within the context of schistosomiasis classified as autoimmune diseases. 1. Cercariae and schistosomula damage caused by cercariae through the skin can cause dermatitis, local papules and itching, a rapid on_set_ and delayed type hypersensitivity. Pathological changes of the capillary dilatation and congestion, accompanied by bleeding, edema, surrounded by neutrophils and monocytes. Experiments show that mice infected with passive transfer of serum and lymphocytes into normal mice, and then inoculated with cercariae (initial contact with cercariae), can produce cercariae dermatitis. Illustrate this in the early immune response is antibody mediated. Schistosomula migration in the host body, the organ through which (especially the lungs) to vascular inflammation, capillary thrombosis, rupture, resulting in local cellular infiltration and spotting. When a large number of schistosomula migration in the body, the patient may include fever, cough, bloody sputum, increased eosinophils, which may be local inflammation and allergic reactions caused by insect body metabolism. 2. Adults caused no significant damage to the pathogenic role of general adult, a few can cause slight mechanical damage, such as intimal go far. However, its metabolites, body secretions, excretions, body off the table outside the cortex, update plasma membrane, etc., in the body can form immune complexes, resulting damage to the host. 3. Damage caused by eggs of schistosomiasis disease caused mainly by the egg. Eggs are mainly composed of the host organizations such as the liver and colon wall, granulomas and fibrosis caused by schistosomiasis is a major disease. Granuloma formation and development of the pathological process is closely related with the development of eggs. Eggs not yet mature, the surrounding host tissue without response or minor response. When the eggs mature within the miracidium, the secretion of enzymes, protein and sugar and other substances known as soluble egg antigen (soluble eggantigen, SEA), can induce granulomatous reactions. SEA through the porous egg shell slow release, sensitized T cells, when re-encountering the same antigen, stimulate sensitized T cells to produce various lymphokines. The results show that: macrophage SEA, and then processed antigens presented to T helper cells (TH), while secretion of interleukin 1 (IL-1), activation of TH, to produce various lymphokines, including white blood cells Interleukin 2 (IL-2) to promote T-cell sub_set_s in proliferation; γ-interferon to enhance macrophage phagocytosis. In addition to the release of lymphokines, there eosinophil-stimulating hormone (ESP), fibroblast stimulating factor (FSF), macrophage migration inhibitory factor (MIF), etc. to attract macrophages, and eosinophils into the fiber cells around the eggs together to form a granuloma, also known as egg nodules. Schistosoma japonicum egg output usually deposited in clusters within the organization, so the large volume of egg granuloma, and its cellular components, the more the number of eosinophils, and plasma cells. Granuloma necrosis often appear center, said the eosinophilic abscess. Often can be seen in the eggs around the antigen-antibody complex reaction, said He Boli phenomenon (Hoeppli phenomen). With hematoxylin-eosin staining of liver biopsy specimens, surrounded by red radiation in the egg-like substance. Schistosoma japonicum egg granuloma formation in animal studies showed that the T cell-mediated allergic type Ⅳ. As the disease develops, the egg miracidia died, the toxin gradually disappear, necrotic material is absorbed, broken eggs, or calcification, the weeks around the epithelioid cells, lymphocytes, foreign body giant cells, epithelioid cells into the final fibroblasts cells and produce collagen fibers, fibrosis, granulomas occur gradually, forming scar tissue. Egg granuloma formation is the host of the causative agent of an immune response. On the one hand destroyed by granulomatous reaction to eggs removed and egg release can be isolated and removed the antigen, reducing the blood circulation in the antigen-antibody complex formation and damage to the body; the other hand, damage to the host granulomatous response to normal organization, continuously generated egg granuloma formation interconnected scar, leading to cirrhosis and intestinal wall fibrosis, trunk type and a series of lesions. Schistosome egg granuloma formation of blood vessels in the tissue, blocking blood vessels, destruction of vascular structures, leading to fibrosis, such lesions were found in the eggs deposited more organs such as liver and colon. In the liver, egg granuloma in the portal branch of the terminal, before the venous sinus, and therefore the general structure and function of the liver is not affected. Severe infection in patients with extensive fibrosis around the portal vein, liver section, and around the portal vein around the long white fibers from different angles into the liver, called trunk-type fibrosis (pipestem fibrosis), is characteristic of advanced schistosomiasis lesions. As the extensive venous sinus obstruction, leading to portal hypertension, the liver, splenomegaly, collateral circulation, the abdominal wall, esophageal and gastric varices, ascites and upper gastrointestinal bleeding and other symptoms, known as the liver and spleen of schistosomiasis (hepatosplenic schistosomiasis). So late schistosomiasis japonica portal blood flow due to obstacles arising due to a chain of pathophysiological changes. 4. Circulating antigen and immune complex schistosome parasites in the host vein, schistosomula, adults and eggs of the metabolites, secretions and excretions, and the parasite into the skin to update the shedding blood, and with the blood circulation to the organization, a circulating antigen. Schistosome infection in the host blood circulation within the main antigens detected: gut-associated antigen (associated antigens, GAA), surface membrane-associated antigen (membraneassociatedantigens, MAA) and soluble egg antigen (soluble eggantigens, SEA). So far, the most studied is gut-associated antigens. The two major components of schistosome GAA, the circulating anodic antigen (circulating anodieantigens, CAA), the gut-associated schistosome proteoglycan antigen and circulating cathodic antigen (circulating anodieantigens, CAA), as a heterogeneous glycoprotein antigen. Proved by indirect fluorescent antibody technique, CAA and CCA are derived from the adult intestinal lining cells, with parasites vomit routed host bloodstream. These circulating antigens of the host phase?