In the less developed nations, hygiene and sanitation remain overriding factors in population health and the burden of waterborne disease. Both morbidity and mortality from diseases, such as cholera, remain high, but the overwhelming burden of diarrhoeal diseases inevitably goes undiagnosed. Enterotoxic E. coli, shigellosis and campylobacteriosis are prevalent amongst bacterial diseases and giardiasis is often diagnosed among protozoan diseases. In terms of viral diseases, hepatitis A is frequently associated with water and rotavirus, and more recently norovirus, infections are suspected to be major causes of gastroenteritis, although they are seldom diagnosed. From the perspective of research and training, and despite the efforts of major international organizations, effective programs that teach basic hygiene and sanitation remain elusive.