1. Unité des Rickettsies, Faculté de Médecine; Université de la Méditerranée; CNRS UPRES A 6020, 27, Boulevard Jean Moulin, 13385 Marseille Cedex 05 France
2. Division of Viral and Rickettsial Diseases; National Center for Infectious Diseases, Centers for Disease Control and Prevention; Mail Stop A-26, 1600 Clifton Rd. Atlanta GA 30333