- Dr C Yang, Yunnan Provincial Center for Disease Control and Prevention, 158, Dongshi Road, Kunming City, Yunnan Province, 650022, PR China;
- Accepted January 16, 2009
- First published February 2, 2009.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.