Last week there was an editorial in the Japan Times that cited increasing numbers of HIV cases in Japan.  At the time I ignored it, thinking that it would not contain any interesting information.  However, my old roommate brought the eitorial to my attention today, quoting this section:

Last year the total number of those infected with HIV in Japan hit a record 6,560 (of which 4,673 were Japanese nationals), following an unprecedented 1,165 (of which 698 were Japanese) new infections reported in 2004, the most recent data available.

Apparently only 71% of HIV infected people in Japan are Japanese citizens.  What does this mean?  Are there really a lot of HIV-positive gaijin wandering around in Japan?  Are foreign prostitutes and promiscuous English teachers spreading HIV in Japan?  Or are the statistics flawed because most sexually active Japanese people are not being tested for HIV?