If I knew exactly who were the girls Darren fucked during his stay in Brazil, I could get the answer in like ten minutes.

But if he, indeed, fucked a tranny BAREBACK, that that´s where he got it from. In Brazil, trannies are way more aware of the HIV risks than the usual hookers.

So, if a brazilian tranny says yes to a bareback without hesitation, then he has the virus and, worse, he KNOWS that, period.