1. Mel & Enid Zuckerman College of Public Health, The University of Arizona, Tucson, AZ;
2. Department of Soil, Water, and Environmental Science, The University of Arizona, Tucson, AZ;
3. College of Public Health, The Ohio State University, Columbus, OH;
4. Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI;
5. Environmental Virology Laboratory, Department of Water Pollution Research, National Research Centre, Cairo, Egypt