The first case of dengue fever was reported on Aug. 27. As of Friday, the number had increased to 141 people in 17 prefectures — not one of whom had traveled abroad. If the asymptotic or unreported cases are included, it's quite possible that figure may be two or threefold.

This deservedly made news for being the first outbreak in Japan since 1942-44 — a time when thousands of Japanese soldiers had been dispatched to the tropics.

According to the National Institute of Infectious Diseases, reported cases of dengue fever in Japan numbered 402 in 2013, but all were believed to have been contracted abroad.