1. Plague Control Research Institute of Siberia and the Far East, Irkutsk, Russia
2. Research Institute for Natural Foci Infections, Omsk, Russia
3. Research Institute for Natural Foci Infections, Omsk, RussiaCenters for Disease Control and Prevention, Atlanta, Georgia, USA
4. Krasnodar, Russia
5. Centers for Disease Control and Prevention, Atlanta, Georgia, USA