1. Laboratory of Virology, National Institute for Infectious Diseases “Lazzaro Spallanzani” (IRCCS), 00149 Rome, Italy
2. French National Agency for Research on AIDS—Emerging Infectious Diseases (ANRS MIE), Maladies Infectieuses Émergentes, 75015 Paris, France
3. Institut National de la Santé et de la Recherche Médicale, Jean Mérieux BSL4 Laboratory, 69002 Lyon, France