The Problem Intestinal worms and parasites. Worms and other parasitic infections (a type of neglected tropical disease) affect around two billion people worldwide. The majority of these individuals most live on less than $2 a day. Three hundred million of these people--roughly the population of the United States--suffer from severe illness, and half of those are school-aged children. The World Health Organization estimates that schistosomiasis alone kills up to 200,000 people a year. Those who work in agriculture or lack access to clean water supplies are at increased risk for schistosomiasis infection. These infections can cause a range of serious health problems that include malnutrition, impaired cognitive and physical development, and blindness. Parasitic infection can also increase the morbidity and mortality of malaria, tuberculosis, and HIV/AIDS. Parasitic worms and other neglected tropical diseases have been demonstrated to reduce the number of years children spend in school--damaging their educational prospects, reducing their future earnings, and ultimately harming developing economies.