Acknowledgment

This publication has been made possible by the dedicated work of Mr. Pierre Léger, who drafted the original manuscript. Mr. Léger, a civil engineer who also holds degrees in environmental and sanitary engineering, is Director of International Division of Medical Care Development, based in Washington. A native of Haiti, Mr. Léger, obtained his graduate degree from New York University and did his postgraduate work in the Netherlands. Thanks also are due to Mr. David Donaldson, formerly of the Pan American Health Organization, and to the Division of Environmental Health Protection of PAHO for their dedicated contribution to the conception and technical content of this manual.