The first indication of what we were flying into was on flight BA7305, a late-afternoon service from London to Milan.

Key points: Coronavirus was first reported in the northern Italian town of Codogno last Friday

Coronavirus was first reported in the northern Italian town of Codogno last Friday It brought about the closure of 11 nearby towns and isolation of 50,000 people

It brought about the closure of 11 nearby towns and isolation of 50,000 people More than 280 people in Italy have been infected, with 11 confirmed deaths

The plane was an Embraer 190, with a capacity of 100 passengers.

Aside from myself and ABC camera operator Andrew Greaves, there were only 13 people on the flight.

The flight attendants spent most of the flight up the back of the plane chatting between themselves.

We landed in an almost empty terminal at Milan's Linate airport.

Inside the cabin of an almost empty British Airways flight from London to Milan. ( ABC News: Andrew Greaves )

Later, a bored car rental attendant told me 30 per cent of that day's flights had been cancelled, and offered to upgrade our car to a Mercedes-Benz.

After we collected our bags, we were shepherded by army medics to a desk staffed by nurses wearing surgical masks and flanked by plain-clothed security officials.

Italian military health specialists take the temperatures of incoming passengers at Milan airport. ( ABC News: Andrew Greaves )

They asked us at which port we had boarded our plane, and read our temperatures before waving us on.

Milan is the capital of Lombardy, the province worst affected by Italy's coronavirus outbreak.

The virus was discovered last Friday in Codogno, a small town of 15,000 people, when a 38-year-old man known only as "Mattia" tested positive for the virus.

By then he had run a half-marathon, played a game of football and socialised with friends.

Within days, 150 other cases of the virus were confirmed in Codogno and the surrounding villages, and by the end of the weekend the country was grappling with an outbreak that had infected more than 200 people.

So far, 11 people have died, and on Tuesday night (local time) there was news of fresh cases in Sicily, Liguria and Tuscany in southern Italy.

In all, the country has recorded more than 322 cases of COVID-19.

Inside the 'red zone'

Codogno is now at the centre of a declared "red zone", where residents are being quarantined in the town until further notice.

Several hundred people, who are on a special list compiled by health authorities of those believed to have come into contact with the virus, have been instructed not to leave their homes — and they're relying on friends and relatives to bring them food and medicine while they await testing.

Gaetano Callea (right) owns a hair salon in Codogno. ( Supplied )

Gaetano Callea, owner of a local hair salon, is one of them.

"We're told to stay home and not let anyone in," he told me via a video call.

"But this is absurd because I have been home since Friday and until they come and test me I cannot leave home or go to the supermarket. We're just waiting."

Clearly frustrated by the delay, Mr Callea suspects the authorities are overwhelmed.

"The situation at the moment is very tough both in terms of the tension we feel in the air, and even economically because businesses are shut," he said.

"But we still have workers to pay and rent to pay.

"So, what's happening is very serious."

The 51-year-old suffers from a heart condition and "in a few days I will run out of medicine", which he described as a "lifeline".

Marketing analyst Nicola Bianchi is quarantined in the nearby town of Casalpusterlengo, where there are police checkpoints in every major street.

He said shopping was difficult because the amount of people permitted in public places was limited.

"We cannot go out all at the same time to buy groceries because people cannot stay in crowds," he said..

"People, of course, are buying more food. It's running out, but we can manage if we have it in our houses."

Nicola Bianchi is quarantined in the town of Casalpusterlengo. ( Supplied )

He's worried for his 88-year-old grandfather, who is in hospital for a fractured leg.

"We cannot go and meet him because the hospital has been shut down," he said.

"He's 88 and my mum is his doctor, is worried, maybe, you know, she cannot go and meet him."

Roadblocks and empty streets

Even in the so-called "yellow zone", which blankets towns 10 kilometres from Codogna, the virus is making its presence felt.

The streets are strangely empty and those who are outside are all wearing masks.

Government notices are stuck to shop windows informing patrons they are allowed to grant entry to only two customers at a time; we had to queue to enter a bar to order coffee, only to discover it was empty inside.

Police stop two vehicles on the outskirts of Codogna in northern Italy. ( ABC News: Andrew Greaves )

At two checkpoints, we saw police turning around hundreds of cars and trucks.

Some of the truck drivers argued, gesturing in frustration.

A truck driver gestures as a police officer checks his papers outside of Codogna. ( ABC News: Andrew Greaves )

I saw one snap a photo of the roadblock on his phone as he reversed his truck, and I expect it was to send to his boss to ask what he was meant to do now.

Some vehicles were allowed into the red zone — local workers and those bringing in supplies.

But it's not clear when the residents of Codogna, and the other villages trapped by this invisible threat, will be free to leave.