1. Menzies School of Health Research, Charles Darwin University, Darwin Northern Territory, Australia
2. Northern Territory Clinical School, Flinders University, Darwin Northern Territory, Australia
3. Department of Primary Industries and Fisheries, Townsville, Queensland, Australia
4. Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, St. Mary's Hospital, London, United Kingdom
5. Health Protection Agency, Plymouth, Devon, United Kingdom
6. Centre for Infections, Health Protection Agency, London, United Kingdom