In Japan, Infectious Disease Surveillance Center (IDSC) of National Institute of Infectious Diseases (NIID) is notified the results of isolation/detection of infectious agents from prefectural and municipal public health institutes (PHIs). Their information are based on the laboratory identification done by PHIs for the specimens collected at sentinel clinics/ hospitals under the National Epidemiological Surveillance of Infectious Diseases (NESID), occasionally at non-sentinel sites and at health centers.

Figure 1．Weekly reports of rubella virus isolation/detection, week 1/2012-week 27/2013

Figure 2．Isolation/detection of rubella virus by prefecture, 2012 & 2013

Figure 3．Age distribution and gender of rubella virus isolation/detection, 2012 & 2013

  In 2013, the reported number of rubella virus isolation/detection was largely increased (Fig.1).

In 2013 (week 1 to 27), the information of rubella virus isolated/detected from 724 cases in 30 of 47 prefectures was reported.  Among 229 strains genotyped, the genotype 2B from 212 cases was dominant (93%).  The genotype 1E from 15 cases follows (6.6%).  The genotype 1a (vaccine type) was reported from 2 persons, one who received MR vaccine, and the other unknown-type vaccine.  Among them, genotype 1E was detected from a person who returned from Malaysia and an undetermined genotype was one from Malaysia/Indonesia (Fig.2). 

　In 2012, PHIs in 24 prefectures reported the information of 231 rubella virus isolation/detection.  Out of 168 strains genotyped, 132 belong to genotype 2B (79%), which included a case who developed rubella after returning from Thailand, the genotype 1E from 35 cases (21%), and genotype 1a from a MR vaccinee (Fig.2).

  A number of rubella viruses were detected from measles-suspected cases, actually from which measles virus was not detected.  A genotype 2B was detected from an encephalitis case.  Three genotype-2B and 3 genotype-not typed were detected from 6 congenital rubella syndrome (CRS) cases.

  In 2012 & 2013, rubella viruses were predominantly detected from 720 males especially in their 20s to 40s.  Among 228 females, the viruses were most frequently detected from 15 to 29 years (Fig.3).

Infectious Agents Surveillance Report, Infectious Disease Surveillance Center,

National Institute of Infectious Diseases