[1] Inst Virol, MRC, Virol Unit, Glasgow G11 5JR, Lanark, Scotland
[2] NIAMSD, Imaging Sci Lab, Ctr Informat Technol, NIH, Bethesda, MD 20892 USA
[3] NIAMSD, Struct Biol Lab, NIH, Bethesda, MD 20892 USA
[4] IFREMER, Lab Genet & Pathol, F-17390 La Tremblade, France