Jpn. J. Infect. Dis., 65 (1), 88-91, 2012

To see a printable version of the article in the Adobe file format, click this [PDF] link.

Hiroshi Yoshikura*

National Institute of Infectious Diseases, Tokyo 162-8640, Japan

Communicated by Ichiro Kurane

(Accepted November 4, 2011)

*Corresponding author: Mailing address: Department of Food Safety, Ministry of Health, Labour and Welfare, 1-2-2 Kasumigaseki, Chiyoda-ku, Tokyo 100-8916, Japan. E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.