subject: Daily tissue Nematodes we need to take seriously [print this page] Daily tissue Nematodes we need to take seriously
Tens of millions of people are infected by dracunculiasis, Toxocara canis cuases blindness, fever and hepatomegaly in humans. The tissue nematodes live in connective tissues of humans. The medically important tissue nematodes Wuchereria, Loa and Onchocerca are called the "filarial worms", because they produce motile embryps called microfilariae in blood and tissue fluids. These organisms are transmitted from person to person by bloodsucking mosquitoes or flies.A fourth species is the guinea worm. Drancuculus, whose larvae inhabit tiny crustaceans (Copepods) and are ingested in drinking water. The nematodes described above cause diseases as a result of the presence of adult worms within the body. In addition, several species cannot mature to adults in human tissue but their larvae can cause diseases. The most serious of these diseases is visceral larva migrans caused primarily by the larvae of the dog ascarid, Toxocara canis.Loa loaThis disease is found only in tropical central and west Africa, the habitat of the vector Chrysops. Humans are infected by the bite of the deer fly (mango fly), Chrysops, which deposits infective larvae on the skin. The larvae enter the bite wound, wander in the body, and develop into adults. The females release microfilariae that enter the blood, particularly during the day. The microfilariae are taken up by the fly during a blood meal and differentiate into infective larvae, which continue the cycle when the fly bites the next person. There is no inflammatory response to the microfilariae or adults, but transient, localized nonerythematous, subcutaneous edema (Calabar swellings) occurs. The most dramatic finding is an adult worm crawling across the conjunctiva of the eye, a harmless but disconcerting event. Diagnosis is made by visualization of the microfilariae in a blood smear. Treatment is done by administering Ivermectin. Control of the fly by insecticides can prevent the disease.Dracunculus Medinensis (guinea fire worm)It causes dracunculiasis. The disease occurs over large areas of tropical Africa, the Middle East, and India. Humans are infected when tiny crustaceans (copepods) containing infective larvae are swallowed in drinking water. The larvae are released in the small intestine and migrate into the body, where they develop into adults. Meter-long adult females cause the skin to ulcerate and then release motile larvae. The cycle is completed when these are ingested in the water. The adult female produces a substance that causes inflammation, blistering, and ulceration of the skin, usually of the lower extremities. The inflamed papule burns and itches, and the ulcer can become secondarily infected. Diagnosis is usually made clinically by finding the head of the worm in the skin ulcer. Metronidazole or thiabendazole are the best options for the treatment of dracunculiasis. Prevention consists of filtering or boiling of drinking water.Toxocara canisIt causes visceral larva migrans. Visceral larva migrans occurs worldwide. Young children are primarily affected. Its mode of transmission is by the fecal oral route.Life cycleThe infective stage is its eggs. The definitive host for Toxocara canis is the dog. Its adult female form in the dog intestine produces eggs that are passed in the feces into the soil. Humans ingest soil containing the egs, which hatch into larvae in the small intestine. The larvae migrate to many organs, especially the liver, brain, and eyes. The larvae eventually are encapsulated and die. The life cycle is not completed in humans. Humans are therefore accidental, dead-end hosts.Pathology is related to the granulomas that form around the dead larvae. The most serious clinical finding is blindness due to retinal involvement. Fever, hepatomegaly and eosinophilia are common. Treatment therapy includes anti-parasite agents such as mebendazole, corticosteriods and antihistamines to counteract the inflammatory reaction of host to the parasite.Dogs should be de-wormed, and children should be prevented from eating soil or stuffs exposed to soil.I am Funom Theophilus Makama. I advertise through writing. As a platinum expert Author, I write lots of articles and hence promote interested websites, companies, groups, organizations, and communities through publishing and distributing my articles. For more information on this interesting venture, click on the link belowhttp://funom-makama.blogspot.com/2010/07/advertising-contracts.html
