Brazilian President Dilma Rousseff wasted little time firing her top aide in May when the country's biggest newspaper reported that he had received $4 million in unexplained income.

Rousseff didn't stop with her chief of staff. In quick succession, she let go of three other ministers publicly accused of everything from receiving kickbacks to charging the government for staying at a love motel. Meanwhile, public outrage had turned into regular street protests.

Those unprecedented actions in the halls of power match what Brazilians say is a new mood spreading across South America's biggest country: People are making it clear in the streets and elsewhere that long-tolerated sins such as bribery, graft and other acts of corruption are no longer tolerable.

Brazilians have long accepted such malfeasance as the necessary cost of doing business, be it in commerce or public service. Every year, the country loses up to $47.4 billion to undeclared tax revenue, vanished public money and other casualties of widespread corruption, according to an August survey by the Federation of Industries of Sao Paulo.

For most of Brazil's history, people have felt powerless to change things. Two decades of military dictatorship starting in 1964 and years of hyperinflation left citizens feeling disconnected from their representatives and from the spending of their tax money.

Now a new middle class is rising on the strength of the country's commodities-driven economy. They're starting to pay taxes and want to know where that money's going, said economist Marcos Fernandes, with the Brazilian think tank the Getulio Vargas Foundation.

Many Brazilians also sense that their continent-sized country is ready to realize its potential as a world economic power, and that the old way of doing business, based on personal connections and under-the-table agreements, is holding the country back, Fernandes said. Brazil's economy grew by 7.5 percent last year.

"This new lower-middle class, middle-middle class is going to step up pressure for better public services," he said. "Internationally we've seen that the growth of these classes changes politics. They're not moved by ideology so much. They want transportation, education. They want public services."

Public anger has also been fueled by regular reports from the Federal Comptroller General, an accounting body that monitors the use of taxpayer money.

On top of that, Brazilian news media is intensely covering the issue, and people are accessing information like never before, Fernandes said.

That's resulted in growing numbers of people taking to the streets to voice their new expectations. Half a dozen cities saw anti-corruption marches on a single September day, and marches hit 18 cities Wednesday.

"I've been indignant about corruption for a long time, but now it's intolerable," said environmental engineer Mateus Mendonca, 28, during a September protest in downtown Rio de Janeiro. "The lack of respect politicians have for the people is explicit."

Such mass actions to demand government accountability have never happened on the current scale, said Gil Castello Branco, founder of the nonprofit watchdog group Contas Abertas, which advocates for transparency in government.

"We're beginning to understand that we are the state, that elected officials are there to represent us," Castello Branco said. "We are the bosses, and they are the ones who owe us explanations. Brazilians haven't been aware of that until now."

The problem has long run deep, touching ministers and small town mayors alike.

Ordinary Brazilians encounter it in the police officer who stops a driver for a ticket but agrees to let the offense go in exchange for beer money. In business, corruption appears in the owner of a private construction firm that pays off an official on the side to secure a lucrative job and evade the public bidding process.

Brazilians often circumvent rules and use bribes and connections to get by and run businesses within a hugely inefficient bureaucracy.

According to the World Bank, Brazil ranks 127th out of 183 economies in ease of doing business. Starting a business, for example, takes an average of 120 days and requires 15 different procedures.

The good government group Transparency International found that Brazil ranked 69th out of 178 countries last year in perceived corruption, putting it ahead of most of its Latin American peers but behind developed countries.

But the eschewing of rules for personal gain can have the most serious consequences.

A blast ripped through downtown Rio on Thursday, killing three people and injuring more than a dozen.

Investigators say the explosion was likely caused by a leak in a restaurant's illegal gas hookup. The establishment didn't have a fire department safety permit allowing it to use cooking gas, according to the city's fire chief. And the gas company serving Rio hadn't provided service to that address since 1961. Yet rescue workers extracted from the charred building six industrial-sized gas cylinders, each with a 99-pound (45-kilogram) capacity. Every government since the restoration of democracy in 1985 has been hit by corruption scandals, including one that prompted President Fernando Collor de Mello's resignation in 1992.

Rousseff's predecessor, Luiz Inacio Lula da Silva, rose to power from the factory floor and took office amid great hope that his tenure would break the cycle of sleaze. Yet in 2005, his government was rocked by one of the biggest corruption schemes the country had seen: a vast network of monthly payouts through which Silva's Workers Party bought legislative support. He denied knowledge of wrongdoing, but his party was scarred.

This year, Rousseff, who had been Silva's chief of staff, brought to the presidency other veterans of Silva's administration, including his finance minister, Antonio Palocci.

Palocci had resigned in disgrace in 2006 after he was seen frequenting a house where politicians received bribes and held all-night sex parties. As president, Rousseff named him her chief of staff.

Despite that pick, Brazilians took note when Rousseff ousted Palocci and dozens of others accused of misconduct. Her approval rating soared to 71 percent in September, thanks largely to the perception that she was taking on entrenched corruption, according to the Ibope polling institute.

Rousseff's approach prompted an erosion in legislative support among allied parties, but Castello Branco said the push for clean government was under way.

"She awakened a sense among Brazilians that maybe the cleaning could happen not just in one room, but in the whole house," he said.

A wide range of groups joined in the movement, from the Federation of Industry of the State of Rio de Janeiro to the National Conference of Brazilian Bishops. A group of lawmakers dedicated to the cause in Congress dusted off 21 bills that target corruption, some having been stuck in the process for more than 15 years.

"It's our job to take the ball from these popular movements and kick it into the goal," said Rep. Francisco Praciano of Amazonas state, coordinator of the 50-member anti-corruption caucus. "For this to work, it needs to have several fronts."

Castello Branco said such actions should only be a start in changing Brazil for good: Society must remain engaged for the anti-corruption movement to produce real results.

"There is no police, no federal accounting investigation, that will fight corruption with the intensity that it deserves if the public is not behind them," he said. "We have to start thinking of the next steps. This can't be just words."