The reductions in American Airlines service to Brazil are noted in this FlyerTalk thread:
http://www.flyertalk.com/forum/american-airlines-aadvantage/1349176-laa-777-300er-77w-schedule-routes-consolidated-32.html
American is reducing (but not eliminating) service to Sao Paulo on the new 777-300 (77W) planes. Currently there are 3 daily flights between Miami and Sao Paulo – two night flights and one during daytime hours. On February 10 the daytime flight will be reduced in frequency to 4 flights per week – on Friday, Saturday, Sunday and Monday. These weekend flights will still use the new 77W.
On April 5 American will switch one of the evening flights to the older 777 aircraft. There will still be one flight each evening from MIA to GRU and vice-versa on the 77W.
No changes have been announced for any other American Airlines flights between the USA and Brazil. This means that there will still be a daily flight to Sao Paulo from New York and from Dallas on the 77W. The daily flight from Los Angeles will also continue, but it uses a Boeing 787. And no changes were announced concerning flights to Rio – American will continue to have daily flights from New York and from Miami (both on a reconfigured 777-200)
Will there be more flight cutbacks? If the economic crisis in Brazil continues I suspect that there will. We will see what happens.