I suspect it’s a translation issue. @noisefree linked in another, less sensational article that says this is dengue fever. And the old name for dengue fever was “break-bone fever”, because of the massive amount of bone and joint pain it caused.

I think it’s probably “bone pain” scrambled in translation, since it’s a dengue fever outbreak.

I hope it’s just a catch all data kind of thing. Like anything anyone has wrong with them gets lumped in to be filtered later. Idk. I’m guessing here.