| 单词 | hookworm | ||||||
| 释义 | hookwormhook·wormH0270200 (ho͝ok′wûrm′)hookworm(ˈhʊkˌwɜːm)hook•worm(ˈhʊkˌwɜrm)n. hook·worm(ho͝ok′wûrm′)
hookwormhookworm,any of a number of bloodsucking nematodes in the phylum NematodaNematoda, phylum consisting of about 12,000 known species, and many more predicted species, of worms (commonly known as roundworms or threadworms). Nematodes live in the soil and other terrestrial habitats as well as in freshwater and marine environments; some live on the deep ..... Click the link for more information. , order Strongiloidae that live as parasites in humans and other mammals and attach themselves to the host's intestines by means of hooks. Hookworm infection in humans is caused by infestation with Ancylostoma duodenale (the European species) or with Necator americanus (the American species). It is found in tropical and subtropical climates, especially where the inhabitants do not wear shoes or stockings and where the soil is contaminated by human excrement. The larva of the hookworm, living in moist soil or mud, easily penetrates the exposed skin, usually the sole of the foot, and is then carried by the blood to the lungs. An early sign of hookworm infestation is a dermatitis at the site of entry, known as ground itch. As the larva passes through the lungs, it causes episodes of coughing with bloody sputum. Raised with the mucus into the mouth, the larva is then swallowed. It may also be swallowed with polluted drinking water or with unclean vegetables eaten raw. By means of its hooks the larva attaches itself to the upper portion of the small intestine, where it nourishes itself on the blood of its host. The larva matures and the female produces eggs, as many as 30,000 per day, that are passed from the intestine with the feces, usually to contaminate the soil still further. The drain on the blood of the host results in anemia. This, together with the resulting abdominal pain and diarrhea, causes general debility. Hookworm is treated with drugs, notably tetrachloroethylene, that loosen and destroy the parasite, as well as with specifics for the anemia and abdominal symptoms. Incidence of this disease, which was once seriously prevalent, has been much reduced by improved sanitation and the wearing of shoes. hookworm[′hu̇k‚wərm]hookwormSee hookworm hookwormhookworm[hook´werm] Larval hookworms enter the body by burrowing through the skin, usually that of the sole of the foot. The first sign of the disease may appear on the skin as small eruptions that develop into pus-filled blisters; this condition is sometimes called “ground itch.” The hookworms then enter blood vessels and are carried by the blood into the lungs. After they leave the lungs, they propel themselves up the trachea, are swallowed and washed through the stomach, and end up in the intestines. Here, if left alone, they will establish a parasitic relationship, using their host's body as a source of nourishment. By the time they reach the intestines, about 6 weeks after they entered the body as larvae, the worms are full-grown adults. Each worm now attaches itself by hooked teeth to the intestinal wall, where it sucks its host's blood by contraction and expansion of its gullet. If large numbers of worms are present, they can cause considerable loss of blood and severe anemia. The symptoms include pallor and loss of energy; the appetite may increase. The thousands of eggs laid every day by each female worm pass out of the body in the stool, in which they can easily be seen. If the stool is not properly disposed of, the larvae that hatch from the eggs may infect other persons. hook·worm(huk'wŏrm),hookworm(ho͝ok′wûrm′)hookwormParasitology A hematophagous nematode of family Ancylostomatidiae–eg, Old World hookworm–Ancylostoma duodenale and New World hookworm–Necator americanus that sensitizes the penetration site–eg, skin, causing 'ground itch', or lungs–eg, Loeffler syndrome as the worms wiggle through, causing eosinophilia and, due to bloodsucking, anemia Lab Rhabditidiform larvae may be confused with Strongyloides stercoralis; eggs may be confused with Trichostrongylus and Meloidogyne spp. See Ancylostoma duodenale, Necator americanus.hook·worm(huk'wŏrm)hookworm Hookworm DiseaseHookworm eggs deposited on the soil in feces mature into larvae capable of penetrating the skin, esp. the bare skin of the foot. An allergic or inflamed rash may develop at the entry site. The larvae pass from the skin into the venous circulation and travel to the alveolar capillaries of the lungs, up the bronchi and trachea and into the gastrointestinal tract. There they mature, attach to the mucous membrane of the intestine, and begin feeding on host blood. The adults secrete an anticoagulant, which promotes additional bleeding. Eventually, the host develops iron-deficiency anemia. Patients sometimes report nausea, colicky abdominal pain, bloating, and pica. Affected children may suffer growth retardation. The adult worms produce eggs that are excreted in the feces, perpetuating the cycle of infection. The detection of these eggs in the stool provides the basis for diagnosis of the disease. TreatmentMebendazole and pyrantel pamoate are used to eradicate the infection. Iron supplements are needed to treat the anemia. hookworma NEMATODE parasite of man that gives rise to anaemia and mental and physical retardation. see ANCYLOSTOMIASIS.Hookwormhookworm
Synonyms for hookworm
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hookworm - parasitic bloodsucking roundworms having hooked mouth parts to fasten to the intestinal wall of human and other hosts