Scientific name: clonorchis sinensis cobbold
Taxonomic status: Platyhelminthes Trematoda
Also known as liver fluke, is liver fluke disease pathogens, domestic distribution in the northern and southern provinces; foreign distribution in Korea, Vietnam, India and the Philippines.
Medium-sized individual, body length 10-25 mm, width 3-5 mm. Adults were leaf-shaped, tapered front end, back end blunt, the epidermis without spines. Oral sucker slightly larger than the ventral sucker. Diameter of about 0.45-0.60 mm. Testicular branch, Tandem 1/3 after the body. Ovarian leaf precedes the testicles, testicular and spermatheca in the ovaries, oval. Pale or reddish-brown in color.
Adult parasites in clonorchiasis parasitic in people, cats, dogs and other mammals, bile duct, the parasite eggs with feces into the water, after being swallowed grain marsh snails, snails and other bean snails and hatch into miracidia, Lo miracidia body through asexual reproduction and develop into a large number of cercariae mature cercariae escape from the snail body, drill a variety of freshwater fish or shrimp, in the body develop into metacercariae, humans and animals are not killed due to consumption of fish Metacercariae death was infection. Patients with soft stools, chronic diarrhea, indigestion, jaundice, edema, anemia, fatigue, cholecystitis, liver swelling, the main complication is primary liver cancer, can cause death.
(A) morphological structure
Parasites soft, flat, thin, transparent, such as leaf-shaped, narrow front end, back end slightly wider body length of 10mm a 25mm. Body width of 3mm ~ smm. The size of the size of the parasite and host, the size and number of parasitic parasitic biliary much about. With oral sucker and ventral sucker. Oral sucker (oral sucker) is greater than the ventral sucker, in front of the worm, ventral sucker (aretabuluzn) located in front of the worm belly about 1/5. Sucker rich muscle, is attached to the organs. Clonorchis sinensis life is red meat, white after fixation, internal organs looming after the parasites 1/3 has two tandem technology like testicle tree, is one of the main characteristics of the pest, so that sticks testosterone flukes.
1. Body wall
The outermost layer of the body wall flukes, electron microscopy studies demonstrated that many large extension from the cytoplasm of cells, the fusion layer formed syncytia (syncytium), wherein the mitochondria, endoplasmic reticulum and pinocytotic vesicles, protein crystals formed small spines, etc. This layer is called the cortex (tegument). Cortex groups are based film (basement membrane), under which a ring of muscle (circular muscle), longitudinal muscle (longitudinal muscle), then the lower of parenchymal cells. Large cell body (including the nucleus) sink to the substance, the cytoplasm by a number of projections (or path) through the cytoplasm of the muscle layer and the surface layer is connected. This particular structure of the cortex not only has a protective effect against the parasite, and the gas exchange between the parasite and the environment, nitrogenous waste exclusion also by diffusion (diffusion) carried out by the surface. Some nutrients, particularly amino acids are ingested parasites by endocytosis.
2. Digestive
Oral sucker central port is located under a spherical port access and rich pharyngeal muscles (pharynx), esophagus swallow short (oesophagus), followed by two intestinal branches, direct back-end along both sides of the parasites. No anus. Clonorchis sinensis to host major bile duct epithelial cells for food, sometimes eat some white blood cells, red blood cells and the secretion of bile ducts inside and can also absorb some nutrients through the body surface, can also secrete enzymes to soften the tissue of the host, in order to facilitate digestion, mainly outside the cell to digest. Food stored in the form of glycogen, fat.
3. Respiratory
No special respiratory row anaerobic (anaerobic) respiration, the use of certain enzymes to decompose in vivo storage of nutrients (such as glycogen), organic acids and carbon dioxide, thereby releasing energy.
4. Excretory system
As a branch of the original tight pipe system, located on both sides of the body, terminating at the end of flame cells. Both sides of the branching tubules metabolic waste collected by the drain pipe to the left and right rear of the body, by the confluence of the two tubes is a little s-shaped excretory sac, and finally discharged from the drain hole at the end of the body.
5. Nervous system and sense organs
Developed, basically similar to the planarian nervous system, is also a ladder next to a pair of pharyngeal ganglion, which issued six forward after each nerve longitudinal rows of six nerves back transverse nerve contact.
6. Reproductive system
(A) the male reproductive organs: testis has a pair of skills were shaped tree branches, are arranged around the parasites after 1/3, each issue an insemination testis tubules (or output line) merged into a small tube 2 Insemination a vas deferens, seminal vesicles expanded into forward, and opening the front line of the seminal vesicles in the male genital pore ventral sucker pass out of the body before. No penis, penis sac (cirrus sac) and prostate.
(2) Female genital mutilation:
Before testis is a slightly lobulated ovaries. Spermatheca oblong, located between the testes and ovaries. Lloyd tube (laurer's canal) connecting one end of the fallopian tube, the other end of the opening on the back of the body, it was considered to have discharged its function redundant role yolk or sperm, some people think it is the degradation of the vagina. Many vitellarium distributed on both sides of the worm, glands merge into each other on each side of a yolk tube (vitelline duct), the total synthesis of yolk in the middle of the worm tubes (common vitelline duct), and then connected to the fallopian tubes. One into the egg chamber (ootype) on the fallopian tubes. It is composed of the fallopian tubes, by the seminal vesicles, Lloyd's pipes and pipe yolk confluence. Into the egg chamber around a group of unicellular glands called plum gland (mehlis' gland), which formed part of the egg shell and yolk ball secretions secretions combine another part may have some lubrication. Uterus (uterus), it is often filled with egg chamber before the eggs into the uterus at the roundabout before the line between ventral sucker and ovary, female genital pore ventral sucker chap before. Clonorchis sinensis no reproductive cavity, Digenea flukes, in addition to the above structure are generally outside the genital cavity of the uterus and into the penis sac of all trades reproductive cavity.
Clonorchis sinensis hermaphrodite, can self-fertilization (self-fertilization), also can do cross-fertilization (cross-fertilzation). Self-fertilization, the sperm from the testes out through the vas deferens, seminal vesicle, genital pore, to the uterus, and finally reached by the seminal vesicles. Cross-fertilization of two worms mate, worms accepted sperm from female genital opening of another body, the spermatheca, but also by Lloyd's to accept the sperm duct to the spermatheca. Combined with sperm in the fallopian tube into the cavity or into a fertilized egg in the egg into the cavity, the outside of each fertilized egg, yolk surrounded by a lot of cells from the yolk gland, as a fertilized egg yolk cell nutrition, while at the same secretion Some substances egg shell formation. Medvedev gland function is to act eggshell formation yolk cells or stimulate the release of substances as well as the activation of sperm yolk, some scholars believe that it has a smooth egg secretions role. Eggs from the egg into the uterine cavity formed to move forward, and finally discharged from the genital pore.
(B) life history
After the fertilized eggs excreted by the parasite. To the person (or cats) a bile duct or gallbladder, bile duct into the small intestine through, and then with the person (or cats) in feces. After the output already mature eggs, which contain miracidia. Eggs was brown, slightly shaped like a light bulb, the top cover, the cover can be seen on both sides of the shoulder-like small protrusions at the bottom of a small protrusions called small warts. The average size of eggs 29μm ⅹ 17μm.
Only when the eggs into the water, after being the first intermediate odd primary (first intermediate host) (grain marsh snails, Chinese marsh snails, snails and other long-horned marsh) swallowed, miracidia (miracidium) that is in the small intestine or rectum from snail eggs escape through the intestinal wall becomes sporocyst (sporocyst), most of the sporocyst soon moved rectum lymphatic clearance, and continue to develop in the area. In sporocyst many embryonic cells form a group each rediae (redia), most of them moved to the liver clearance, and the rest moved to the lymphatic clearance rectum, stomach and gills. In the first 23 days after infection, the body's germ cells rediae group gradually develop into cercariae (cercaria). Cercariae tadpole shape, split and tail, body eye point, melting glandular tissue, into the follicle cells and square capsule excretion, etc.; Minister tail, dorsal fin has a similar peritoneal membrane. Last purchase mature snails from escaping, can live in water 1 to 2 days, in the case of the second intermediate odd main (second intermediate host) when swimming, some freshwater fish or shrimp then invade the body. China has been reported to be the second intermediate host insects mainly carps, such as carp, bream, carp, crucian carp, dace soil, wheat and rice fish shrimp, prawns, etc. Tail off in the host body formed metacercariae (metacercaria). Metacercariae oval capsule excretion considerable, no eye point, most metacercariae parasites in fish muscle. Also available on the skin, fins and scales. Metacercariae infection of human or animal eating undercooked or raw fish containing metacercariae, shrimp and infection. Metacercariae in the duodenum, the wall is fluid and trypsin digestion helmet, larvae escape through the common bile duct bile duct hosts moved to grow and develop, grow into adults after a month and begin to lay eggs. So people describe, Clonorchis sinensis dog is not final host (final host). Some people think that the adult life span of 15 to 20 years. Metacercariae resistance, though not strong, was immersed in 70 ℃ hot water within 8 seconds to death, but the use of frozen, salted or in the method of oil inside, it can not kill the metacercariae in short just inside.
(C) treatment of
Multiple clinical treatment using praziquantel, which features a side effect is relatively small, short course. |