James A Ayukekbong1, Tomas Bergström2. 1. Department of Infectious Diseases, Section of Clinical Virology, Institute of Biomedicine, University of Gothenburg, Gothenburg 41346, Sweden. Electronic address: james.ayukekbong@microbio.gu.se. 2. Department of Infectious Diseases, Section of Clinical Virology, Institute of Biomedicine, University of Gothenburg, Gothenburg 41346, Sweden.