Travel visas are required for people of many nationalities traveling to Brazil, including U.S. citizens. If you are a Harvard student, professor or staff member and require a Brazil visa, you can apply for it either directly with the Consulate of Brazil in Boston, or via the visa expediting agency "A. Briggs" or "TRAVISA". Links to all are below.
Consulate: http://boston.itamaraty.gov.br/en-us/how_to_apply.xml
A. Briggs agency: http://www.abriggs.com/locations/Boston/boston_passports.php
TRAVISA: https://travisa.com/harvard/
If you choose to secure your visa with the help of A. Briggs or Travisa, please mention to the agency that you are from Harvard, as Harvard has negotiated a fee discount.