1 Centre for International Health Protection, Robert Koch Institute, Berlin 13353, Germany. Electronic address: moserf@rki.de.
2 Africa Centres for Disease Control and Prevention, Regional Collaborating Centre for Eastern Africa, Kenyatta National Hospital, Nairobi, Kenya.
3 Norwegian Institute of Public Health, Oslo 0213, Norway; Africa Centres for Disease Control and Prevention, African Union Commission, Addis Ababa, Ethiopia.
4 Africa Centres for Disease Control and Prevention, African Union Commission, Addis Ababa, Ethiopia.