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Chapter 4 : The Filarial Infections: Lymphatic Filariasis (Elephantiasis) and Dracunculiasis (Guinea Worm)
This chapter talks about lymphatic filariasis (LF) and dracunculiasis. Approximately 90% of the world’s LF cases are caused by the nematode parasite Wuchereria bancrofti. The adult worms live for eight years in the lymphatics. They produce microfilariae that enter the bloodstream and are transmitted person to person through a mosquito vector. The morbidity and pathology of LF result from adult W. bancrofti worms in the lymphatics, which cause dilation (lymphangiectasia), obstruction, lymphedema, and, in some cases, elephantiasis. The chronic morbidity and disfigurement resulting from LF exact a huge economic toll, almost $1 billion in losses annually to the Indian economy. Much of this loss is from reduced worker productivity. In addition, the stigma of LF has an enormous but still poorly quantified social impact. Transmission of LF in poor rural communities can be interrupted by mass drug administration of anthelmintic drugs that target the microfilariae. These drugs include diethylcarbamazine (DEC) and ivermectin. Dracunculiasis is caused by the guinea worm, Dracunculus medinensis. The adult D. medinensis worm grows to almost 1 yard in length and lives in the subcutaneous tissues of the legs and feet (as well as elsewhere). The adult female worm produces a blister that ruptures in water, with the release of immature D. medinensis larvae. The major tools of the dracunculiasis eradication program (DEP) include provision of safe water, health education, and case containment.