- Correspondence to Mr Jonathan Crofts, Health Protection Agency Centre for Infections, 61 Colindale Avenue, London NW9 5EQ, UK;
- Accepted August 25, 2010
- First published June 21, 2011.
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.