PARASITIC WORMS Essay Example | Topics and Well Written Essays - 1500 words

PARASITIC WORMS - Essay Example A holistic approach that involves preventive measures, drug therapy and non-drug measures is employed in tackling the menace of worm infestation. Human parasitic worms are a major health challenge in the developing world. To a far less degree, however, worm infestation in the developed countries is also a problem. Broadly speaking, three groups of worms cause parasitic worm infestation in man. These are the roundworms (also known as the nematodes), the flukes (also called the trematodes), and the tapeworms (the cestodes). The roundworms are responsible for the majority of parasitic worm infestations in the developing world. These roundworms are usually the large roundworms (Ascaris lumbricoides), the whipworm (Trichuris trichiura), and the hookworm (Acyclostoma duodenale). A few cases of infestation by these worms in the developed world are found in travelers and immigrants. On the other hand, threadworm (Enterobius vermicularis) is the roundworm that causes the most parasitic worm infestation in the United Kingdom. Other known roundworms include Strongyloides stercoralis that causes strongyloidiasis, and the Necator american us (the new world hookworm) that causes necatoriasis. The flukes include all members of the Schistosoma species, and the cause schistosomiasis or bilharzia depending on the species that is contacted. The tapeworms are the Taenia species and their intermediate hosts are beef (Taenia saginata), pork (Taenia solium), or fish (Dipyllobothrium latum) from where they are passed to man (the definitive host). The dwarf tapeworm (Hymenolepsis nana) is passed from man to man.(Clark, 2006) Pathophysiology Threadworms are threadlike in structure and their infestation is commoner in children. They are passed from one person to another by the ingestion of their eggs. These eggs develop into larvae in the small intestine and are hatched to produce young worms. The worms mature in a couple of weeks and the adult females migrate to the anus where they lay numerous microscopic eggs. As a result of itching felt in the anus where these eggs are laid, the anus is scratched by the human and the eggs are reingested through the hand-to-mouth route. Infestation could also be through migration of hatched eggs up to the rectum (Clark, 2006). Strongyloides stercoralis is commoner in warm region, though its distribution is world wide. First infestation is through larvae deposited in soil that enter the skin and develop in the small intestine. Subsequent infestation is by larvae passed in stools of infected individuals which re-penetrate the skin of the same individual. A possible complication is the life threatening strongyloides hyper infestation syndrome(Clark, 2006). In infected individuals, the Schistosoma species lay eggs that are excreted in the human stool (Schistosoma japonicum and Schistosoma manson) or in the urine (Schistosoma haematobium) Larvae hatched from these eggs are called the miracidia, and they enter snails which are the intermediate hosts. Consequently, infective larvae called the cercariae are released from these snails and enter humans that wade in water in which they are present. These larvae migrate to the human intestine or the bladder where they mature, mate and produce eggs. Initial infestation may be asymptomatic, causing only a transient itching or