Jpn. J. Infect. Dis., 55, 2002

Laboratory and Epidemiology Communications

Isolation of a Wild Type Measles Virus Classified as
Genotype H1 in Osaka City
Hideyuki Kubo*, Nobuhiro Iritani, Tsukasa Murakami and Kosuke Haruki
Department of Microbiology, Osaka City Institute of Public Health andEnvironmental Sciences,
Tojo-cho 8-34, Tennoji-ku, Osaka 543-0026
Communicated by Takashi Kawamura(Accepted November 18, 2002)
Measles is one of the important infectious diseases inpediatrics (1). The World Health Organization (WHO) has
recommended genotyping of wild isolates of the measlesvirus. Thus far, eight clades from A to H and a total of 20
genotypes have been classified (2). Because measles virus
genotypes are considered to be associated with geographicallocation and chronological isolation, it has been consideredthat a genotype can reveal its own origin and transmission
pathway (3). In August 2002, in Osaka City, we isolated awild type measles virus classified as genotype H1 from apatient. Detailed are provided in this report.
The patient was a 4-month-old girl, a resident of Nishinari-ku in Osaka City. The virus was transmitted to her from hermother. The virus was isolated in B95a cells from a blood
specimen obtained on the sixth day of illness (12 August2002). The isolated virus was designated MVi/Osaka C.JPN/
32.02 according to the WHO nomenclature. For genotyping,a 650 bp fragment including the 3´ terminus of the N gene
was amplified by RT-PCR. About 550 bp in the PCR amplicon
were sequenced directly using an ABI PRISM 310 DNA
sequencer (Applied Biosystems, Foster City, Calif., USA),and the 3´ terminal 456 nt sequence of the N gene wasdetermined. We constructed a phylogenetic tree using theneighbor-joining method to confirm the genotype of theisolate, using the reference measles virus N gene sequences
designated by WHO (the database is available from GenBank).
We found that MVi/Osaka C.JPN/32.02 was assigned*Corresponding author: Tel: +81-6-6771-3147, Fax: +81-6-67720676, E-mail: kubo@iphes.city.osaka.jp
177Jpn. J. Infect. Dis., 55, 2002
genotype H1, represented by Hunan.CHN/93/7 (N geneaccession No. AF045212) (Fig. 1). A BLAST2 search (http://blast.genome.ad.jp/) based on the 456 nt of the 3´ terminal of
the N gene revealed a 99.6% homology between our isolate
and MVs/WA.AU/30.01. The amino acid sequence was 100%
identical between the two. With MVs/Florida.USA/25.00,
MVs/NSW.AU/52.00, and MVs/Toronto.CAN/8.01, it shared
98.9% homology, and one amino acid difference was observed.
We have been analyzing the genotypes of wild measles
virus isolates as part of Infectious Disease Surveillance inOsaka City since 1997. Until 2001, all isolates were genotype

D3 or D5, which have been considered indigenous to Japan.
No other genotypes were detected (4). Regarding isolationsof genotype H1 wild type measles virus in Japan, isolates ofthis genotype were reported from Tokyo and Kawasaki Cityin 2001 (5). In Osaka City, the present case was the firstdetected. None of the family members of the infected 4month-old baby had a history of travel abroad. This background data may suggest that the H1 wild type measles virus
was circulating in Osaka City. Though the H1 genotype has
been considered indigenous to China and Korea (2), MVi/Osaka C.JPN/32.02 had the highest homology to MVs/Fig. 1. Phylogenetic analysis of measles viruses based on the nucleotide sequence in the 3´ terminal 456 nt of the N gene.
Reference strains designated by WHO are indicated by accession number to GenBank. The genotypes are shown in parentheses.
In addition to the isolate MVi/Osaka C.JPN/32.02 reported herein, three other strains isolated in Osaka City in 2002, of genotype
D5, are also shown.

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1999. Wkly. Epidemiol. Rec., 74, 429-440.
2. World Health Organization (2001): Nomenclature fordescribing the genetic characteristics of wild-type measlesviruses (update). Wkly. Epidemiol. Rec., 76, 241-256.
3. Bellini, W. J. and Rota, P. A. (1998): Genetic diversity ofwild-type measles viruses: implications for global
measles elimination programs. Emerg. Infect. Dis., 4, 2935.
4. Kubo, H., Iritani, N. and Seto, Y. (2003): Co-circulationof two genotypes of measles virus and mutual change ofthe prevailing genotypes every few years in Osaka,
Japan. J. Med. Virol., 69, 273-278.
5. National Institute of Infectious Diseases and Tuberculosis and Infectious Diseases Control Division, Ministryof Health, Labour and Welfare (2001): Measles, Japan,
1999-2001. Infect. Agents Surveillance Rep., 22, 273’274’.

WA.AU/30.01, a strain detected in Australia in 2001. The next
highest homology was to strains identified in the USA andAustralia in 2000 and in Canada in 2001. Analyses of thetransmission pathway of these measles viruses to suchcountries and the comparison of sequences among measles
viruses, including H1 viruses isolated recently in indigenous
countries and MVi/Osaka C.JPN/32.02, will reveal the transmission pathway of the genotype H1 wild type measles virus
to Osaka City.
The article appeared in the Infectious Agents Surveillance
Report, vol. 23, no. 11, p. 288, 2002 in Japanese.
REFERENCES
1. World Health Organization (1999): Measles. Progress
towards global control and regional elimination 1998-179