How unusual is this strain?

It is unusual because normally swine influenza doesn’t affect humans and when it does it often doesn’t survive. The fact that in Mexico so many people have been affected has suggested it’s a mixed human/swine virus. That is to say a person gave it to a pig before it crossed back into humans. So it’s unusual that it has affected so many people and so many young people. It is a cause for concern.

How serious is it when it can be transmitted from human to human?

It’s normally not very serious, people recover very quickly, but in Mexico there have been deaths. There have been some cases in the US — 20 today — but they’ve responded well to treatment.

People with reduced immunity — commonly very young or old, or people on drugs, or sick for other reasons — will be more vulnerable. …The level of deaths is still quite low in Mexico and of course in a country like that they don’t have a very good healthcare system and that seems to be the issue, they’re not using anti-viral medication.

How does it morph from bird, pig and human?

It’s a complicated process. The influenza virus is a street smart bug, it’s continually changing. That’s why we have different vaccines every year, our immune systems aren’t effective against it. You come up with a new variant that is potentially effective in humans, and it can be passed on from one person to another.

Bird flu is a similar situation, you get it when people and birds are close together, mixing. Flu is common in most animals and there are many different variants. The trouble with humans is that when we come across a flu strain we haven’t encountered before, our immune systems can’t cope and we get really sick.

With previous pandemics, people have had no resistance and the virus swept through the world accompanied by deaths.

When did we last see a strain of this type?

We think this is a new strain and we don’t know a great deal about it. Swine flu is present all the time and there have been occasions before when people have picked up swine flu. This is still a very early stage in trying to work out what’s going on here.

How quickly can it spread?

This swine flu is quite infectious, but in some cases it might not be a serious infection. You’d just have flu like symptoms, but there is also diarrhea and vomiting in this variety too. But in the early stages it will seem just like an ordinary flu.

How easily can it jump borders (go from country to country)?

People can pass the virus on very easily by crossing borders and we’re very used to flu, and people having those symptoms. In Australia we’re well equipped to deal with it.

How easy could it have been to arrive in Australia undetected?

Quite easily, if someone had quite recently visited Mexico or the US, they may not be very sick when they travel. It is impossible to stop it coming into Australia.

What’s the quickest way to shut it down?

Treatment of people who are sick. Our bodies will become immune if we do catch it and recover. It’s still early days to guess how virulent or serious it is.

Is it more serious than the Avian flu that we’ve heard so much about?

It depends what it is, we don’t know yet.

Why did it originate in Mexico?

Who knows? They’ve got a lot of pigs infected with human flu. It happens anywhere there’s a lot of pig farming. I don’t think there are any particular issues specific to Mexico but personal hygiene might be different, living conditions, contact with animals, and so on that is different in Australia.

Can we still eat crispy bacon?

You can indeed, there’s no reason you can’t eat cooked pork. That would kill the virus.

What about crackle? (we really love crackle)

Certainly, I imagine roasting would kill the virus nicely.