UNESCO "Common water and sanitation-related diseases" Unicef http://www.unicef.org/wash/index_wes_related.html http://www.unicef.org/wash/index_wes_related.html http://www.unicef.org/wash/index_wes_related.html "Common water and sanitation-related diseases" illness and death http://www.unicef.org/wash/index_wes_related.html UNESCO diarrhea, cholera, and intestinal worms http://www.unicef.org/wash/index_wes_related.html UNESCO nearly 4 billion cases of diarrhea Unicef diarrhea, cholera, and intestinal worms http://www.unicef.org/wash/index_wes_related.html http://www.unicef.org/wash/index_wes_related.html "Common water and sanitation-related diseases" UNESCO diarrhea, cholera, and intestinal worms