We regularly see Brazilian Bancos samples that try to steal the credentials of Brazilian bank users. These are generally delivered via spam or drive-by downloads. However, recently a different form of threat was spotted that specifically targets Brazilian users.
W32.Selfish is a file infector that checks what your default language pack is and only proceeds to execute its payload if you are using the Brazilian Portuguese Language pack. If you are using a different language pack, W32.Selfish will simply execute the infected host file and exit.