70 Views | 25 Downloads
Sarah E. Smith-Jeffcoat, Centers for Disease Control and Prevention, 1600 Clifton Road NE, Mailstop H24-5, Atlanta, GA 30329-4027, USA; email: uyi7@cdc.gov
See publication for full list of authors and acknowledgments.
This is a publication of the U.S. Government. This publication is in the public domain and is therefore without copyright. All text from this work may be reprinted freely. Use of these materials should be properly cited.