Prof Jonathan Ball

But if people do become unwell, then their risk of death is increased.

Some of the individuals will die, between 5 and 15%, for example.

I think it's fair to say that outbreaks generally are relatively well contained and we don't get huge reports of significant outbreaks.

What's unusual here is you're talking about what are essentially a captive contained bunch of people.

It means that if there is human to human transmission, then they're at greater risk because they are incarcerated on this cruise ship.

If you think about most outbreaks, it's usually in populations who aren't constrained to a single place and co-living with one another.

I think the WHO are working on the hypothesis that it's probably the Andes virus, which is quite prevalent in South America and in particular in Argentina.

And so, you know, both of those scenarios, either people picking up the virus before they boarded the ship in Argentina or on the ship.

stop offs on route the likelihood of people being exposed is certainly true we know that rodents are one of the most prevalent groups of animals worldwide and wherever you've got large rodent populations there's a chance of becoming exposed i think one of the things that's

very noticeable about hantavirus infections and we used to see this a lot in Europe is often virus cases or outbreaks would mirror good years for things like beech tree nuts so these periods of great production of seeds and essentially because there's so much food the rodent populations explode

and therefore the hantavirus prevalence in those animals increases.

I mean, that's just as an aside, but I think the hypothesis of rodents stowing away on the ship is certainly plausible.

It's very difficult to keep rodents off ships.

If we think about one hantavirus called the sole hantavirus, it's pretty much worldwide distributed, and that's because it infects the common rat, so Rattus norvegicus.

And we know that the common rat is found in every continent.

It's very good at stowing away on ships and being transported as humans go about their daily business.

So I think one of the questions that the authorities, that the scientists will be trying to work out is how did this outbreak occur so that similar ones can be prevented in future?

you will try and minimize the amount that people are mixing, but also, and I'm sure this has already happened, there'd be a process of deep cleaning the ship.

So trying to make sure that there aren't areas where there is contamination.

So it's all about cleanliness and then isolation.