I'd be more worried about finding a tranny surprise in Thailand. I think they have more per-capita trannies than Brazil.

After 30 days, as long as the tests are honest, it's probably no riskier to work with those girls than any other: if they test HIV- at or after the 30 day mark they're probably really HIV-.

But, if someone shoots a bi or tranny scene, condom or not, she should be avoided for some time, probably 30 days. As long as bi (and I think tranny) porn allows HIV+ performers to work then they can't be trusted, and a condom doesn't add a lot of protection (in my opinion).