1 French Military Center for Epidemiology and Public Health, CESPA, Camp de Sainte Marthe, 13014 Marseille, France. Electronic address: f_de_laval@hotmail.com.
2 Department of Infectious Diseases and Tropical Medicine, Laveran Military Teaching Hospital, Marseille, France.
3 Department of Biology, Robert Picqué Military Teaching Hospital, Bordeaux, France.