In a follow-up to an earlier story, Portuguese health officials say that cooling towers at a fertilizer plant were the likely source of an outbreak of Legionnaires’ disease, Reuters reports.

Image/CDC
Image/CDC

Environment Minister Jorge Moreira da Silva said the cooling towers at Adubos de Portugal, a unit of Spanish company Fertiberia have been shut down in an attempt to get the growing outbreak under control.

Since the last report on the outbreak Monday, the case count nearly doubled to 233 and one additional death has been reported, bringing the total fatalities to five. Dozens are currently hospitalized in intensive case for their illness.

Four parishes in the district of Vila Franca de Xira, about 25 km (16 miles) northeast of Lisbon, had the greatest concentration of the cases, Reuters reports.

Legionnaires’ disease is caused by a type of bacteria called Legionella. The Legionella bacteria are found naturally in the environment, usually in water. The bacteria grow best in warm water, like the kind found in hot tubs, cooling towers, hot water tanks, large plumbing systems and decorative fountains.

People get Legionnaires’ disease when they breathe in a mist or vapor (small droplets of water in the air) containing the bacteria.

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