Abstract
Measles is an acute and highly contagious disease caused by measles virus (MeV). In Japan, since the last epidemic in 2007 and 2008 caused by the genotype D5 strains, the government introduced a catch-up-vaccination program for teenagers during fiscal years of Japan 2008-2012 and the mandatory case-based reporting system for the nationwide elimination. Furthermore, the laboratory confirmation based on genotyping has been performed to clarify the source of infection and to support the interruption of measles cases. While such preventive measure have been conducted, the number of measles cases decreased steadily after the last epidemic. Finally, Japan was internationally verified as having achieved the measles elimination by the World Health Organization Regional Office for the Western Pacific in March 2015. The continuous elimination and high coverage of vaccination for MeV have been maintained nationally. However, the imported or import–associated cases have been sporadically occurred. In Hokkaido, the northern islands of Japan, the genotypes H1, D4, D8, and B3, all of which were imported or import-associated strains, were detected in total 17 measles cases after the last nationwide epidemic. Here, we present the occurrence of measles and surveillance activities in Hokkaido during 2006-2015.
