- Correspondence to:
Dr S R Anderson
North West London Health Protection Unit, 61 Colindale Avenue, London NW9 5EQ, UK;
- Received January 3, 2006
- Accepted October 5, 2006
- First published November 13, 2006.
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.