Dr
Peter Helbling
Infectious Diseases Section
Department of Communicable Diseases
Swiss Federal Office of Public Health
P.O. Box
CH - 3003 Bern
SWITZERLAND
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Dr
Simone Graf
Scientific Collaborator
Infectious Diseases Section
Department of Communicable Diseases
Swiss Federal Office of Public Health
P.O. Box
CH - 3003 Bern
SWITZERLAND
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Dr
Valeria Gaia
Istituto Cantonale di Microbiologia
via Mirasole 22a
6500 Bellinzona
SWITZERLAND