When Jovita Rosa approaches people while canvassing in Guará, a satellite city of nearby Brasília, most strike an inherently suspicious pose. Even here in Brazil's capital, where government is the lifeblood of the economy, politicians seem to be an unloved group, not surprisingly in a country where their numerous misdeeds dominate the media far more than any accomplishments.

But when Rosa introduces herself as one of the leaders of the Ficha Limpa (Clean Record) initiative, people's attitudes change. Some ask for more fliers to pass out to family and friends. A bar owner offers to organise a gathering of locals to hear her election pitch.

The initiative is popular because it was an attempt to sweep the criminals out of Brazil’s political class. Rosa helped lead a campaign that gathered up 1.6 million signatures, enough to force the Brazilian congress to vote on a proposal to bar anyone who had a conviction upheld by a higher court from holding public office.

Forced into a corner, legislators reluctantly approved the measure in 2010, and since then thousands have been barred from public office at municipal, state and federal level. It is a rare advance in a country where corruption remains entrenched and is responsible for worrying levels of disillusionment with the political class.

Heart of power

Now Rosa is seeking election to the nearby modernist congress building, designed by

Oscar Niemeyer

, so as to bring her anti-corruption campaign to the heart of power. An auditor in Brazil’s public health service, it was the corruption she uncovered in her job – and the political efforts to prevent auditors, such as herself, ending it – that turned this grandmother of six into a political activist.

"In Brazil it is not the lack of money that explains poor public services but corruption, and corruption flourishes because hidden business interests do not want public services to work, as that would direct people away from things like private health plans," she says.

Rosa's campaign should resonate strongly. After all, Sunday's vote, which, as well as a new congress, will also elect a new president and state governors, is the first since huge street protests last year against the poor state of public services and the political corruption most Brazilians hold responsible for it. And it will take place after an election cycle in which the problem of corruption has again been prominent. The campaigns of Marina Silva and Aécio Neves, the two main opposition candidates for president, have faced questions about wrongdoing and President Dilma Rousseff has been placed on the defensive by accusations that her coalition allies looted the state-controlled oil giant, Petrobras.

‘Very difficult’ task

But, even so, Rosa says it will be “very difficult” for her to win one of the eight seats in Brazil’s Federal District, which includes Brasília and its satellite cities. The reason for this is an example of just how hard it is to clean up Brazilian politics.

Rosa's disadvantage is largely due to her refusal to accept campaign donations from companies. In a year that will see 25,000 candidates spending a total of €23 billion on campaigns – enough to fund the federal government's flagship social programme, Bolsa Família, for six years – Rose is relying on small donations from friends and supporters. With less than a week of the campaign left, she has raised just over €2,000.

This is a serious handicap when it comes to building a ground staff and funding a media campaign, vital in Brazil, where elections are now fought more in the media than on the street. For all the warmth Rosa encounters on the campaign trail, she cannot personally canvass the federal district’s 1.9 million voters.

“There are more candidates from civil society, like Jovita, now running, but they are largely invisible because they lack economic backing,” says Filipe Leão, head of the Institute for Inspection and Control, an anti-corruption pressure group formed by public auditors and prosecutors. “The central quest for Brazilian society is how it confronts the economic power of special interests which manages to undermine many candidates who have popular support.”

It is these special interests that are at the heart of cronyism and corruption in Brazil, says Marlon Reis, a judge who heads the Movement to Combat Electoral Corruption. He cites as an example from the current campaign the fact that the leading corporate donor is a beef producer that received more subsidised credits from state banks than any other company in recent years. As well as being the biggest single donor to President Rousseff's re-election bid, JBS is financially backing another 100 candidates in other races.

“In Brazil, companies with no links to government do not donate to election campaigns, only those that do,” says Reis. “They donate to buy influence. It is not ideologically motivated but a business decision, and the proof of this is that they spread their donations across the ideological spectrum. The link between political campaign contributions and private profit – licit or otherwise – is clear.”

A changing Brazil

But although her own campaign is facing an uphill task because of the odds stacked against it, Rosa is confident that Brazil is changing, in part thanks to increasing prosperity. “Before, the poor couldn’t even formalise their demands,” she says. “But now the ‘new citizens’ of the emerging middle class are opening their eyes.

“They have higher expectations, and we will have better public services when people demand them of their politicians. And this will require an end to corruption.”