incubation period

rubellaに関しては以前，Koyamamoto先生が取り上げられておられましたが（rub-は「赤」でしたよね。），ここではincubation periodをおさえておきます。文字通り，「潜伏期間」です。そういえば，H. E. Palmerの教授法で英語学習の最初の６週間をListeningにあてることを彼はこう呼んでいました。（Shou-VR*）

Rubella cases in Japan top 10,000 in 2013

The number of rubella cases in Japan this year has already topped 10,000 -- more than four times the total for the whole of 2012, the National Institute of Infectious Diseases has announced.
The institute said 10,102 people in Japan had been infected over the 23 weeks up until June 9. Seventy-seven percent of the patients are men, 80 percent of whom are aged between their 20s and 40s.
This year infections spread from the Tokyo metropolitan area in January. Now they are being reported in all of Japan's prefectures. Tokyo topped the list with 2,565 patients, followed by Osaka Prefecture with 2,243, Kanagawa Prefecture with 1,220, and Hyogo Prefecture with 855.

Rubella, also known as German measles, is caused by the rubella virus. Its symptoms include fever, a whole-body rash, and swollen lymph nodes. It has an incubation period of two to three weeks, and it can spread when infected people cough or sneeze.

http://mainichi.jp/english/english/newsselect/news/20130618p2a00m0na008000c.html