She left home at the age of 14, after facing domestic and sexual violence, working as a prostitute and travelling through several states, including the mining areas of Serra Pelada and Itaituba, in the mid-1950s.
In Belém, working at night on the streets around the commercial centre, she began her activities in support of the rights of sex workers.
[4] In 1987, Barreto founded, together with Gabriela Leite, the Brazilian Network of Prostitutes, one of the first organizations in support of sex workers in Brazil.
This network was to play an important role in establishing the International Whores' Day, celebrated every year on 2 June.
She established the Group of Women Prostitutes of the State of Pará (Gempac), which combats prejudice against sex workers.