This article is part of the Guardian's World Cup 2014 Experts' Network, a co-operation between 32 of the best media organisations from the countries who have qualified for the finals in Brazil. theguardian.com is running previews from four countries each day in the run-up to the tournament kicking off on 12 June.

Thiago Silva had not been feeling well for a while by the time Porto ran out of patience with him in August 2005. A year earlier, the Portuguese club had signed the Brazilian defender, right after the departure of José Mourinho to Chelsea, as part of their effort to rebuild a squad that had been plundered by European rivals after their surprise Champions League triumph. But after only appearing for the reserves, Silva had been shipped out to Dynamo Moscow.

He was 20 years old and seemed unable to match the pace of his team-mates. Porto's medical team couldn't find the source of whatever was making Silva complain of flu-like symptoms, including an irritating cough. It was only in Russia that doctors finally found out that Silva's lungs were on the verge of collapsing due to tuberculosis.

Despite significant progress in diagnosis and treatment, TB remains one of the deadliest diseases in the world, having killed 1.3 million people in 2012. Most cases of contamination and death occur in developing countries, within low-income families – the usual cradle for most non-European footballers. While in western Europe it has been virtually eradicated, in Russia it is still active, which explains why Dynamo's doctors finally nailed down what was not only holding Silva back, but also slowly killing him.

"The doctors told me I would be sidelined for 12 weeks because the lungs were compromised. I didn't know what to do", explains the defender, who spent the first two months locked in a hospital room to avoid spreading the disease.

It would get worse: Silva spent 24 weeks in hospital and in total did not play for a year. For the second time it looked as if a career as a footballer was slipping through his fingers – just as he had felt at 13, when the Rio de Janeiro club Flamengo turned him down after a short spell at their youth academy.

Crestfallen, Silva went home and announced to his mother he was quitting. "I had to remind him there weren't a lot of good jobs around for a boy from the reality we lived in. That seemed to put him back on course," reminisces Angela.

She was by his side when he returned in 2006, using his contacts to find a place at another Rio side, Fluminense, where he had also spent a few months at youth level. A year later, he would win the Brazilian Cup and marshal a defence that conceded only 39 goals in 38 league games. While 2008 would include the disappointment of losing the Copa Libertadores title at home to the Ecuadorian minnows LDU, the year finished with a double triumph: Silva dominated Cristiano Ronaldo in a 6-2 demolition of Portugal by the Seleção in a friendly, and soon after Milan announced that they had paid a figure of around £9m to sign the defender.

"It was unbelievable: after everything I had been through, there was the chance to play for one of the biggest clubs in the world and to learn my trade in Serie A, famous for its defensive proficiency," says Silva.

He stayed in Italy for almost four years, playing 93 games and scoring five goals, including a peach of a header against Barcelona in the Champions League. His Seleção debut took place at the Beijing Olympics in 2008, where hopes for a gold medal were dashed by a 3-0 defeat to Argentina in the semi-finals.

Silva watched the 2010 World Cup from the substitutes' bench but in the first post-tournament squad was promoted to a starting place. The armband came two years later, ahead of veteran team-mates such as Dani Alves and even Ronaldinho.

In last year's Confederations Cup, after playing through pain in the last stages, including the final against Spain, Silva finally lifted a trophy as the Seleção captain, which he now dreams of doing again on home soil at the World Cup. By the time Brazil had played Spain off the park last June, he had already become the world's most expensive defender thanks to PSG forking out £37m to convince Milan to sell.

Soon he would be also be wearing the armband for PSG, which meant he had to deal with a huge degree of scrutiny from public, media and team-mates. However, performances on the pitch and a decision to say no to Barcelona have helped to make the 29-year-old a firm favourite in Paris.

"I have immense responsibility for club and country but that doesn't scare me," he says. "It is a privilege to be a football player and there are many people who will never have a chance to make it. I know what it is to think your career is over so I respect the second chance that life has given me."

Life hasn't been a bed of roses since; thigh injuries have worried him in the past two seasons and PSG have failed to make the semi-finals of the Champions League in agonising fashion. Silva, however, has learned the true meaning of the word perspective.

Fernando Duarte writes for uol.com, the Guardian and the Observer

Follow him here on Twitter

Click here to read the tactical analysis of Brazil

Click here to read the secrets of the Brazil players