MILAN (Reuters) - Italy raced on Sunday to contain the biggest outbreak of coronavirus in Europe, sealing off the worst affected towns and banning public events in much of the north as a third patient died of the illness.

Authorities in the wealthy regions of Lombardy and Veneto, which are the focal point of the flare-up, ordered schools and universities to close for at least a week, shut museums and cinemas and called off the last two days of the Venice Carnival.

The civil protection unit said the number of cases of the highly contagious virus totaled 152, all but three of them coming to light since Friday.

“I was surprised by this explosion of cases,” Prime Minister Giuseppe Conte told state broadcaster RAI, warning that the numbers would likely rise in the coming days. “We will do everything we can to contain the contagion,” he said.

The latest death was an elderly woman from the town of Crema, some 45 km (28 miles) east of Italy’s financial capital Milan. Like at least one of the other people who have died, she had been suffering from serious underlying health issues, officials said.

The number of certified cases of the illness in Lombardy rose to 110 from 54 a day earlier, while in Veneto some 21 people were diagnosed with the virus, including two people in Venice, which was packed with tourists for carnival season.

Health officials reported isolated cases in the neighboring regions of Piedmont and Emilia Romagna.

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The regional governor of Veneto, Luca Zaia, said he had dealt with numerous natural disasters during his long career, including floods and earthquakes. “But this is the absolutely worst problem that Veneto has faced,” he told reporters.

Almost a dozen towns in Lombardy and Veneto with a combined population of some 50,000 have effectively been placed under quarantine, with locals urged to stay home and special permission needed to enter or leave the designated areas.

In Milan, residents rushed to stock up on essentials, while some parents decided to take their children out of the city.

“Today is madness. It feels like we’re in Baghdad. We can’t restock shelves quick enough,” said a shop assistant at the Esselunga Solari supermarket in Milan, declining to give her name because she was not authorized to speak to the media.

‘PATIENT ZERO’

Lombardy and Veneto together account for 30% of Italy’s gross domestic output. Any prolonged disruption there is likely to have a serious impact on the whole economy, which is already close to recession.

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Tourism looks certain to take an immediate hit, with schools across the country calling off trips, including traditional week-long skiing holidays.

Milan’s famous La Scala opera house canceled performances and bars and discos in Lombardy were told to close by 6 p.m. (1700 GMT). Some major sporting events were postponed, including four Serie A soccer matches scheduled for Sunday.

Health authorities are trying to work out how the outbreak in the north started.

Initial suspicion in Lombardy fell on a businessman recently returned from China, the epicenter of the new virus, but he has tested negative. In Veneto, doctors tested a group of eight Chinese visitors who had been to the town that was home to the first fatality, but again, they tested negative.

“We are (now) even more worried because if we cannot find ‘patient zero’ then it means the virus is even more ubiquitous than we thought,” Zaia said.

Before Friday, Italy had reported just three cases of the virus - all of them people who had recently arrived from the Chinese city of Wuhan, where the illness emerged late last year.

The World Health Organization (WHO) said it was concerned by the upsurge in new cases and a lack of clarity over its spread.

“I am sending a ... team to Italy to work together to learn about virus spread and (how to) contain it,” the WHO’s European Regional Director Hans Kluge said on Twitter.