The review of the scientific literature and development of the text for the presentation was done with the assistance of Tom Littlefield, John Detlin and Tosin Adjanor, formerly of the School of Publiic Health, University of Michigan. The presentation has benefited immeasurably from comments on earlier drafts by Dr. Robert Wahl (Michigan Department of Community Health), Richard Badits (Washtenaw County Health Department) and Mary Lee Hultin (Michigan Department of Environmental Quality).

This project is supported by Cooperative Agreement Number U59/CCU517742-03-04 from the Centers for Disease Control and Prevention (CDC). Contents are solely the responsibility of the authors and do not necessarily represent the official views of the CDC.