BRASILIA, July 16 (Reuters) - President Dilma Rousseff's approval rating plummeted and her re-election chances have dimmed in the month since massive protests of poor public services, corruption and other complaints shook Brazil, a new poll published on Tuesday showed.
The number of Brazilians who approve of her government's performance fell to 31.3 percent in July from 54.2 percent in June. The number of those who think it has done a bad job soared to 29.5 percent from 9 percent, the survey by polling firm MDA Pesquisa said.
The poll is the second to be released since the protests began. A previous survey, by pollster Datafolha, also suggested that the myriad factors that led to the demonstrations, from the high cost of living to the poor quality of public health and education, have quickly undermined Rousseff's once-towering approval ratings.
According to the new poll, commissioned by private transport sector lobby CNT, Rousseff's personal approval rating fell to 49.3 percent in July from 73.7 percent in June.
The poll showed that 84.3 percent of Brazilians approve of the protests that drew 1 million people onto the streets of Brazil's main cities when the they peaked in June.
Of those surveyed, 33.4 percent said they would still vote for Rousseff, who is expected to run for re-election next year.
Meanwhile, 20.7 percent favor former presidential candidate and environmentalist Marina Silva and 15.2 percent would vote for Aecio Neves, the expected candidate for the main opposition party PSDB. Another 7.4 percent said they would vote for Eduardo Campos, the governor of Pernambuco state.
The poll of 2,003 people was conducted July 7-10. The study has a margin of error of 2.2 percentage points. (Reporting by Anthony Boadle; Editing by Paulo Prada and Maureen Bavdek)