 1. Background Infections with soil-transmitted helminthes STH occur throughout the developing world and remain a major public health problem in the poorest communities. Infection is caused by four main species of worms commonly known as roundworms Ascaris lumbricoides, whipworms Trichuris trichiura and hookworms Ancylostoma duodenale and Necator americanus Bethony et al., 2006. It is estimated that STH affects more than 2 billion people worldwide, of which 450 million have significant morbidity attributable to their infection, and hence are one of the most important neglected tropical diseases. Children and pregnant women are the two most vulnerable groups. Children experience growth stunting and diminished physical fitness as well as impaired memory and cognition, resulting in impaired childhood educational performance and reduce school attendance; pregnant women suffer significant morbidity with hookworm-associated anemia likely contributing to maternal mortality Bundy et al., 1992; Stoltzfus et al., 1996; Crompton and Neisheim, 2002; WHO 2005; Bethony et al., 2006. 