According to World Health Organization calculations, some 1.5 million children die each year across the world from diarrheal disease and 94 percent of the cases are due to unclean water, poor sanitation, and inadequate hygiene. But the detrimental effects of these problems are by no means limited to children: they have severe and long-lasting effects on individual health and development, which taken as a whole put great stress on many developing nations. For example, illness from poor sanitation has been estimated to cost Cambodia and Vietnam over $1 billion in lost Gross Domestic Product every year due to missed workdays.