 3. Materials and methods 3.1. Study Population School children between 4 and 18 years old are the focus of this study because of two main reasons: school children are normally a major target for regular treatment with anthelminthic, because they are the group that usually has the heaviest worm burdens for A. lumbricoides and T. trichiura, and are steadily acquiring hookworm infections. In addition, they are in a period of intense physical and intellectual growth Bundy et al., 1992; Crompton and Nesheim, 2002. Deworming schoolchildren has a considerable benefit on their nutritional status Stoltzfus et al., 1996, Curtale et al., 1995, physical fitness, appetite, growth Stephenson et al., 1993 and intellectual development Nokes et al., 1994. 