Another person travelling with them has also contracted the disease, said the Rev Nicholas Hudson, deputy rector of the English College. Health authorities are inspecting the buildings located near Piazza Farnese in the centre of the city for traces of the Legionella bacterium that causes the disease. The air conditioning systems on the buses the priests used to take them to the pilgrimage sites are also being inspected. Legionella grows in soil and in water and can infest plumbing, air conditioning ducts and water storage tanks found in buildings. People catch the disease by inhaling contaminated water vapour, usually in shower systems or air conditioning systems.
Victims suffer from pneumonia-like symptoms.
The disease can be fatal, particularly in the elderly. The English College was founded in 1579 to prepare English candidates for priesthood. Several of its seminarians sang in a choir that entertained the Queen when she was in Rome on Tuesday.