1. National Centre for Epidemiology and Population Health, Research School of Population Health, Australian National University, Canberra, Australia.
2. South Australian Department for Health and Wellbeing, OzFoodNet, Adelaide, Australia.
3. OzFoodNet, Communicable Diseases Branch, Queensland Health, Brisbane, Australia.
4. Australian Government Department of Health, OzFoodNet, Office of Health Protection, Canberra, Australia.
5. Department of Health and Human Services, OzFoodNet, Communicable Disease Epidemiology and Surveillance, Melbourne, Australia.
6. OzFoodNet, Communicable Disease Control, Health Protection Service, Australian Capital Territory Health Directorate, Canberra, Australia.