Flaviviruses like dengue and Zika are single stranded RNA viruses that cause dengue fever and congenital Zika syndrome, respectively. We used ALFA tag and fluorescent nanobodies binding ALFA tag to study the early events of flavivirus infection in human cells using confocal microscopy. Zika viruses expressing ALFA tag were generated and binding of the nanobody to the tag was studied in virus infected cells and the results will be discussed.