Tuesday, Dec. 11, 3:46 p.m. EST: Nelson Mandela's lung infection could be pneumonia: South African officials say that Mandela's lung infection is "recurring," which is often a sign of pneumonia. ABC News reports: 
As elderly people become more and more infirm, they have a decreased cough response and may aspirate oral secretions into their lungs, raising the risk of infections. And if someone is bedridden, their breaths become more shallow, raising the risk even more.
It may seem surprising that it took so long for Mandela's diagnosis to be made public. However, it's possible that it took this long to make a diagnosis.
Elderly people respond differently to pneumonia, meaning they might lack common symptoms like fever and cough, and instead show signs of confusion. The evaluation of change in physical or mental condition in someone of Mandela's age is broad with much testing needed to make a diagnosis.
Pneumonia is a leading infectious cause of death in the elderly. But with proper treatment, many do recover.
Nelson Mandela, 94, whose recent illness has caused widespread concern in South Africa, where he was the first democratically elected president, is being treated for a lung infection and is "receiving appropriate treatment and responding to the treatment," his spokesman said on Tuesday.
The anti-apartheid leader's history of lung problems is intertwined with his legacy of activism. He first contracted tuberculosis in 1988, just after he was moved from the notorious Robben Island prison to another jail to ease the apartheid government's efforts to negotiate with him about a possible release. "Madiba" -- as he is called in his home country -- fought off a similar infection in 2011. Military doctors, the Huffington Post reports , say he's susceptible to such illness because of his age and the 27 years he spent behind bars.
His ongoing hospitalization has caused growing concern in South Africa, a nation of 50 million people that largely reveres Mandela for being the nation's first democratically elected president who sought to bring the country together after centuries of racial division.
The tests Mandela underwent at 1 Military Hospital near South Africa's capital, Pretoria, detected the lung infection, presidential spokesman Mac Maharaj said in a statement.
"Madiba is receiving appropriate treatment and he is responding to the treatment," Maharaj said, referring to Mandela by his clan name as many do in South Africa in a sign of affection.
In January 2011, Mandela was admitted to a Johannesburg hospital for what officials initially described as tests but what turned out to be an acute respiratory infection. The chaos that followed Mandela's stay at that public hospital, with journalists and the curious surrounding it and entering wards, saw the South African military take charge of his care and the government control the information about his health. In recent days many in the press and public have complained about the lack of concrete details that the government has released about Mandela's condition.
Read more at the Huffington Post.