In Japan, prefectural and municipal public health institutes (PHIs) report isolation/detection of infectious agents from specimens collected by sentinel clinics and hospitals under the National Epidemiological Surveillance of Infectious Diseases, other medical institutions and health centers.

Figure 1．Weekly reports of rubella virus isolation/detection, week 1/2012-week 10/2013

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

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

Figure 4．Weekly isolation/detection of rubella virus by prefecture, week 5-week 9/2013

  From week 21/May of 2012, reports of rubella virus isolation/detection was increased (Fig.1).

  In 2012, rubella virus isolations/detections from 230 cases in 23 of 47 prefectures were reported.  Among 150 viruses genotyped, predominant was  genotype 2B, which was identified from 123 cases, followed by genotype 1E from 26 cases. In addition, genotype 1a (vaccine type) detected from a vaccinee after MR vaccination was reported. A considerable number of rubella viruses were detected by laboraotry diagnosis for measles-suspected cases, from which measles virus was not detected. One genotype 2B was detected from an encephalitis case. Two genotype 2B and 2 genotype not typed were detected from 4 congenital rubella syndrome (CRS) cases (Fig.2).

　 From week 1 to week 10 of 2013, PHIs in 15 prefectures reported 78 rubella virus isolation/detection.  Among 38 genotyped, 36 were genotype 2B including a case who developed rubella after returing from Thailand and 2 genotype 1E (Fig.2).

   Rubella viruses were predominantly detected from males especially in their 20s to 40s. Among females, the viruses were most frequently detected from 15 to 29 years (Fig.3).

From week 5 (January 28-February 3) to week 9 (February 25-March 3) of 2013 (as of March 7, 2013)

   During five weeks from week 5 to week 9 of 2013, isolations/detections of genotype 1E from 2 cases in Chiba Prefecture, genotype 2B from 27 cases in 5 prefectures, genotype not typed from 26 cases in 8 prefectures were reported (Fig.4).

Infectious Agents Surveillance Report, Infectious Disease Surveillance Center,

National Institute of Infectious Diseases