Neglected tropical diseases are a medically diverse group of
tropical infections which are especially common in low-income populations in developing regions of
Africa,
Asia, and the
Americas. They are caused by a variety of pathogens such as viruses, bacteria, protozoa and helminths. Different organizations define the set of diseases differently. In sub-Saharan Africa, the
impact of these diseases as a group is comparable to
malaria and
tuberculosis. Some of these diseases have known preventive measures or acute medical treatments which are available in the developed world but which are not universally available in poorer areas. In some cases, the treatments are relatively inexpensive. For example, the treatment for
schistosomiasis is
USD $0.20 per child per year. Nevertheless, control of neglected diseases is estimated to require funding of between US$2 billion to US$3 billion over the next five to seven years.