Soil-transmitted helminth (STH) infections are a major public health problem especially in the developing nations. The disease burden depends on the regional ecological conditions and also on the local standards of the social and economic development of the people. The species of soiltransmitted helminths that infect humans are concentrated in the tropical and subtropical parts of the developing world. These include the large roundworm, Ascaris lumbricoides, the whipworm Trichuris trichuria, and the hookworm Ancylostoma duodenale.
