Overnight, the normally bustling streets of cities like Milan and Venice were deserted, their sprawling piazzas and picturesque walkways silent and devoid of people.

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But this tranquility betrayed a very different reality for Italians at the front lines of the pandemic.

"It seems relaxed because everyone is staying inside and people are cooking and looking at old photos and doing work at home," said Francesco Longo, director of the Centre for Research on Health and Social Care Management at Bocconi University in Milan. "But in the hospitals, it's like a war."

D'Antiga said that at his hospital, almost half of the 1,000 beds are dedicated to treating patients with COVID-19, the disease caused by the coronavirus. Most other operations at the hospital have scaled back significantly or ground to a halt.

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"In the gastroenterology ward, internal medicine and other wards, they have to send away patients and only admit those with COVID-19 — even in the neurology ward," D'Antiga said. "We have 20 to 30 patients coming in every day requiring admission, but we've run out of beds. It's a really difficult situation."

What makes the situation even worse is that some of the beds are being used to treat medical personnel themselves.

"Here, probably 20 to 30 percent of health care professionals got infected," D'Antiga said. "In my department, I have 25 pediatricians, and currently 10 are off sick. This is the same in other departments, and it's a major challenge."

Although the majority of those who have tested positive so far have experienced mild symptoms, the most serious cases can result in respiratory failure. Nearly 13,000 of Italy's coronavirus patients are hospitalized with symptoms, and of those, more than 2,000 are under intensive medical care, straining hospitals' resources.

D'Antiga said 80 of the 100 beds in his hospital's intensive care unit are occupied by coronavirus patients hooked up to ventilators, but hospitals are rapidly running out of beds and the equipment needed to keep patients alive.

The limited resources are forcing doctors to make excruciating decisions about whom to treat — and who may be beyond help.

Although cases vary, doctors typically take into account a patient's age and condition, which is standard practice even without being in the midst of a pandemic, according to D'Antiga. So far, he said, doctors are mostly heeding the same criteria when they do have to make tough choices.

"Outside of an epidemic, if a 90-year-old person comes in with severe pneumonia, we likely wouldn't admit the patient into intensive care and intubate them," D'Antiga said. "We do have to select, unfortunately, but at the moment, at least we don't have to select among those who would have been treated in normal times."

But that could change, he added. And as the virus spreads, the heart-wrenching situation in Lombardy could be intensified in other regions of Italy and in other countries.

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"What we're seeing in Italy is what we're likely to start seeing in hospitals around the world in the coming weeks and months," said Yascha Mounk, a political scientist at Johns Hopkins University in Baltimore. "One of the characteristics of this disease is it has a very long incubation period. It takes a long time for it to start overburdening the health care system, but once it starts, the increase is very rapid."

In Venice, a doctor in the region's main hospital who spoke on the condition of anonymity said that she and her colleagues are already treating 92 coronavirus patients but that they are anticipating an onslaught still to come.

"We are struggling, but we know we are not in the worst moment of the outbreak," she said. "To work in these conditions is really exhausting. Everyone is feeling mentally exhausted."

Her hospital has already created improvised ICUs, and doctors and nurses across the northeast are being deployed to vulnerable areas. Resources in and around Venice, which has had even more time to prepare than Lombardy, are already becoming strained.