MERS coronavirus

13 May 2014

Interview with

Wendy Barclay, Imperial College

The MERS-CoV coronavirus, was in the news this week after health officials issued Coronavirusadvice to passengers when a man from Saudi Arabia was admitted to hospital in Chicago after flying through Heathrow although he's now been discbarged. He was on a British Airways plane from Riyadh and those sitting near him were advised to contact the NHS if they felt unwell.

MERS-CoV stands for Middle East Respiratory Syndrome coronavirus and it seems to be spreading from Saudi Arabia, with nearly 500 people infected so far and more than a hundred deaths. Now new research suggests that you should you steer clear of camels if you want to avoid catching it.

Kat Arney caught up with virus expert Professor Wendy Barclay, from Imperial College, to get the latest.

Wendy - MERS is a newly discovered virus and it's a member of a class of viruses called the corona viruses. Until just a few years ago until the early 2000s, the only corona viruses that we knew about that infected human beings caused mild colds and then around about 2003, along came a brand new corona virus called SARS which many listeners will have heard of, which of course, was a much more serious disease in humans and caused death. Now, we have this other new virus called MERS which is in the same family.  So genetically speaking, it's similar to those but coming from a different place, a different geographical part of the world and obviously, causing again, much more serious respiratory infections at least in some people.

Kat - What do we know about where this virus has come from?

Wendy - Well originally, people thought that the virus came from bats and that may well still be the case. Bats are the group of mammals which seem to harbour many, many viruses which can occasionally be very harmful if they cross in to people. SARS, we think came from bats originally and Ebola virus, and other things that are much more familiar to listeners also come from there. Probably, the ancient precursor of MERS has come from bats. But in now seems because of the recent data that the direct origin of the viruses that have been infecting people in the middle east are camels. This MERS virus seems to be widespread in dromedary camels in places like Saudi Arabia and Oman. People seem to be catching the virus through some sort of contact with the camels.

Kat - Now, this seems very strange to me. Are there any examples of people catching diseases from their camels before?

Wendy - Not that I'm aware of, but I think what's very interesting is that now, we start looking at camels. The camels themselves seem to have lots of different viruses in them. The corona viruses in general seem to sit in animal species and occasionally, jump across into people. So, there are other corona viruses which have now been discovered which sit in other animals in that part of the world - in the Middle East because that's where people have been really looking recently. For example, goats and sheep are other common animals that are farmed in that part of the world and they've also got corona viruses in them. But these ones don't appear at the moment to be jumping into people. I think it's quite likely that lots of the animals that we deal with on a daily basis have got loads of viruses in them. But only rarely do they actually cross into humans.

Kat - And this new virus does seem quite scary and you're saying that viruses can be harboured by all kinds of animals that we may live closely with or work with. Should we actually be concerned about this new virus outbreak? How scared should I be?

Wendy - Well, at the moment, the number of cases of MERS is in the hundreds - not necessarily in the thousands yet. When we have a new virus like this, there's a combination of two things going on. One is that the virus itself perhaps is being able to jump into humans more frequently but another is that the harder people look, the more they find it as well. So, we have to be careful not to assume straight away that everything has completely changed. It might just be that we're picking these up, now that we're looking. But we must emphasise that so far, this virus is jumping across from camels into humans but isn't really passing from one person to another very efficiently. Although there is some human to human transmission, that isn't what we would call self-sustaining. So at the moment, this virus isn't about to cause a pandemic because we need sustained human to human transmission for that to happen. On the other hand, in some individuals, the MERS virus has been very serious, but many of those people who suffered the worst cases are people who've already got something else wrong with them. They've got what we call comorbidities - health problems, perhaps an immune system that isn't working properly or they're rather elderly and frail and not able to cope with this virus. In healthier people, the viruses only caused much milder disease.  At the moment, we should watch very carefully what's going on. Keep a check because viruses can mutate and can change their characters. But I don't think this is about to break into a pandemic tomorrow.

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