The boy, who has not been vaccinated, was tested for the virus after his leg became paralysed.
He lives with his parents in a cut off village near the south central African country’s border with the Democratic Republic of Congo, where nine polio cases have been reported this year.
The United Nation's children’s agency (Unicef) is warning that it might be the start of an epidemic.
"The province has declared an emergency because last year there were 33 cases of polio in Angola and this year so far there were only four,” said Unicef’s Dr Koen Vanormelingen.
Polio is highly infectious and especially affects young children, and they become paralysed. It is spread through contaminated food and water. Once the virus gets into the digestive system, it multiplies and can spread into the nervous system.
Last year, Angola ran a mass vaccination programme to immunise all its children under five years-old. Children need three to four polio vaccines to be protected against the crippling disease.
Better sanitation and good hygiene also go a long way to lower the incidence of new infections. But to properly wipe out the highly infectious disease, reaching every last child through routine immunisations is vital.
The Angolan government has been putting money into both and had planned to stop the spread of the virus polio transmission by the end of 2010. This was part of a broader polio vaccination campaign aiming to reach 72 million children in 15 African countries.
But sometimes it is hard to make sure every child has each of the immunisations they need to stay protected from Polio. “Sometimes mothers are a bit careless about routine vaccination,” said Dr Antonio Sebastiao Pascoal, who works in the capital, Luanda. “And some live in very remote areas, so it is difficult for health personnel to reach them,” he told Unicef. “But we have to reach every child, or we will not get rid of polio.”
At the end of 2004, Angola was on the cusp of wiping out Polio, and it had three consecutive years without new cases. Then, in 2005, the wild poliovirus reappeared. Angola now has one of the biggest polio caseloads in Africa.
Although it is one of Africa's major oil producers, Angola is still one of the world's poorest countries. It is struggling to overcome the physical, social and political legacy of the 27-year civil war that ravaged the country after independence from Portugal in 1975.