Japan's lesson in A (H1N1) cases

The explosion of the "non-imported" cases of A (H1N1) flu in Japan should teach us on adopting stricter preventive measures, says an article in The Beijing News. Excerpts:

With the first internally infected case being confirmed on May 16, the number of confirmed cases in Japan soared up in a few days. Since most of the infected haven't been abroad, local media name them as "non-imported" cases.

As we all know, flu virus is always exported around the world from the point of origin of the infection. Thus many Japanese analysts suspect that the so-called "non-imported" cases are actually imported. In other words, the imported virus, which by some chance bypassed the entry quarantine inspection, infected local people. Although there are different channels of infection, the origin is still North America.