At a news conference in the city on Monday, the director-general of health, Francisco George said that since the last week of July there had been 16 cases of legionnaire's reported in the Greater Oporto region, two of them picked up abroad.


Of the five people who were in hospital on Wednesday afternoon, George told Lusa, all are doing well.


There is another patient in hospital in Lisbon with the same disease, but that case is not related with those in the north of the country, he said.


On Saturday, Porto's Hotel Boa-Vista undertook a treatment of its internal water system on suspicion of contamination by the bacteria that causes legionnaire's. Apart from one Swedish and one French citizen who stayed in the hotel and contracted the disease, there is one other person who also stayed there and is currently in hospital in Lisbon.


The last major outbreak of legionnaire's in Portugal was in November 2014, when 12 people died and 375 were infected in Vila Franca de Xira, north of Lisbon. The outbreak was brought under control in two weeks.