1. New York City Department of Health and Mental Hygiene, New York, New York, USA;
2. New York City Department of Health and Mental Hygiene, New York, New York, USA;Centers for Disease Control and Prevention, Atlanta, Georgia, USA;
3. New York State Department of Health's Wadsworth Center, Albany, New York, USA;
4. Public Health Research Institute, Newark, New Jersey, USA;
5. Public Health Laboratories, New York, New York, USA
6. Centers for Disease Control and Prevention, Atlanta, Georgia, USA;