In many ways, Washington Castro was a typical resident of Rocinha, the immense redbrick favela that towers over Rio de Janeiro’s Atlantic coast.

Industrious, God-fearing and the offspring of migrants from Brazil’s parched and impoverished north-east, he supported two young children by working two separate jobs and wore a suit and tie when attending his local church.

“He was a marvellous boy. He worked Monday to Monday,” his grief-stricken father, José Osmar Alves da Silva, remembered as he reflected on his son’s death. “Now there’s this hole inside of me and I just can’t make sense of anything.”

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Castro died of suspected Covid-19 last Saturday at age 27 – one of at least six Rocinha residents to lose their lives to the coronavirus as it begins what many fear could be a devastating march through some of Latin America’s most vulnerable communities.

“He was a cutie … Whenever we met he was always wearing the same smile,” said Cecília Vasconcelos, a childhood friend who grew up with him in this sprawling hillside community of some 100,000 residents in southern Rio.

The coronavirus appears to have been brought into Brazil by members of the country’s middle and upper classes as they returned from February holidays in Europe or the United States.

In Rio and São Paulo, many of the early infections were concentrated in the richest neighbourhoods, such as Copacabana and Gávea, where Castro had worked as an assistant at an accountancy firm and a poolside waiter at a club for Brazil’s wealthy elites.

Facebook Twitter Pinterest Washington Castro, 27, from Rocinha.

One of the most famous clusters was Rio’s Country Club, an ultra-exclusive enclave of privilege and power just three miles from Rocinha where at least 60 of the 850 members were infected.

But two months after Brazil’s first reported Covid-19 case the disease is making headway in the deprived, densely populated favelas of both cities, with potentially far-reaching political and humanitarian consequences.

“You can see that it’s moving towards the urban peripheries – gradually, but it’s getting there,” said Paulo Lotufo, an epidemiologist at the University of São Paulo, warning that its proliferation in such places could exact a terrible human toll on residents lacking access to private healthcare or sometimes even basic sanitation.

“I tend to believe that in some places we’re going to see something on the scale of Ecuador,” where hospitals have been overwhelmed and bodies dumped in the streets, Lotufo warned.

Pedro Doria, a Rio-based writer, said he believed coronavirus’s spread through the favelas could also carry a heavy political price for Brazil’s president, Jair Bolsonaro, who has called for containment measures to be relaxed in an apparent attempt to ingratiate himself with the poor.

“Right now what is hurting people [in the favelas] is the economy. So right now Bolsonaro is making a lot of sense to them,” Doria said. But he thought attitudes would change “the moment people we love start dying around us”.

“Depending on how the pandemic goes – especially in the the urban peripheries and the favelas – Bolsonaro will lose a lot of his support,” Doria predicted, speculating that it could even end his presidency through impeachment.

“People will not forget that he said it was OK to go out on the streets.”

Play Video 8:37 Bolsonaro won't help with coronavirus, so Brazil's favelas are helping themselves - video

So far at least 18 people have reportedly lost their lives to Covid-19 in Rio’s favelas, which house about 20% of the city’s 6.7 million residents.

At least 140 cases have been detected, 54 in Rocinha, which is one of the communities closest to the city’s affluent south zone.

Other deaths have taken place in some of Rio’s most deprived areas including Acari, Manguinhos and the City of God favela made famous by Fernando Meirelles’s film.

Wallace Pereira, a community leader in Rocinha, said he feared a lack of testing meant the true numbers were in fact far higher.

“We’re facing a public disaster here,” he said, warning that the political skirmish between Rio’s governor, who has ordered residents to stay at home, and Bolsonaro, who has downplayed the pandemic, was leaving favela residents confused and exposed.

“People are getting sick and they have nowhere to go,” Pereira said. “The situation is getting worse because many people are going around saying: ‘This virus won’t get me’ – which is a fantasy.”

Across town in the portside Morro da Providência, Rio’s oldest favela, Maurício Rodrigues de Oliveira, 64, was found dead last Tuesday by neighbours who suspect Covid-19 was the cause.

Facebook Twitter Pinterest Community leader William da Rocinha, wearing a protective face mask and gloves, delivers aid donations to a resident of the Rocinha favela in Rio de Janeiro this week. Photograph: Ricardo Moraes/Reuters

“The day before he complained of a temperature and fainted in the street,” said Ladelson Soares, a 41-year-old neighbour.

“He was a wonderful person – a waiter in some of Rio’s most famous restaurants,” said Soares, who claimed authorities had taken two days to collect his corpse.

The death has left many neighbours – already struggling with the economic impact of lockdown – in panic.

“Today I got some money together to buy hand sanitiser because I’ve got two kids at home. But I know that means we won’t have the money to eat,” said Claudene Carvalho, an unemployed local who found his body and has been begging community leaders for help.

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For Castro’s family the tragedy began on the morning of 6 April when he set off for work on the number 539 bus.

Shortly after reaching the office Castro began feeling ill and went to a nearby public health clinic where he was admitted complaining of a headache and breathing difficulties.

By then, Covid-19 had already killed more than 500 Brazilians. On Friday the death toll hit 3,670. But – apparently relaxed about his situation – Castro sent his dad a WhatsApp photo in which he appeared wearing an oxygen mask. Nobody imagined what was to come.

Two days later Castro was rushed to a hospital for Covid-19 patients in western Rio where he was intubated on arrival. “We’d go there – but we couldn’t see him,” his 56-year-old father remembered. “We only talked to the doctors.”

Facebook Twitter Pinterest A cemetery worker stands before the coffin of a woman who is suspected to have died of Covid-19, at her burial in Rio de Janeiro. Photograph: Léo Corrêa/AP

After 10 days in intensive care – and, for relatives, 10 days of prayer – Castro was declared dead about 4.30am on 18 April, the death certificate listing severe acute respiratory syndrome as the official cause of death. He left two children, Maria Clara and Pierre, aged three and seven.

Not far from Castro’s former home in Rocinha, another family is also in mourning.

Antônio Edson Mariano, a 67-year-old street vendor who sold biscuits on the beach, died on 30 March – three days after first complaining of a stomach ache – and was the first of the favela’s residents killed by the coronavirus.

On the day of his cremation, Mariano’s wife, Maria Lúcia Moreira Mariano, was herself taken to hospital, where she was given the same diagnosis and informed of her partner’s death.

But as she fights for her own life, Maria has yet to be told of another fatality. One day after her admittance, the couple’s 45-year-old son, Alexandre, also lost his life to Covid-19.