Want to avoid the vomiting bug Disinfect your sink now!
01:33 GMT, 4 December 2012
Thousands of people are currently battling the winter vomiting bug — and the chances are that if you haven’t got it yet, then you soon will.
The number of people affected is 50 per cent higher than this time last year, according to the Health Protection Agency — and given that the usual peak is January, it could be a very bad winter, with millions falling ill.
The cause of all this misfortune is a humble virus, the norovirus — also known, rather unimpressively, as the small round-structured virus.
Viruses normally get into the body via the hands into the mouth, or through rubbing your eyes or touching your face
Viruses are the cause of many everyday ailments, from vomiting illnesses to colds and flu, warts and cold sores.
Here, we reveal the latest findings about how to tackle them…
VIRUSES LOVE A COLD SURFACE
The ideal environment for a virus is a cold, hard surface, such as a loo seat or even a kitchen draining board.
Professor Ian Jones, a virologist from Reading University, says: ‘In fact, a virus is likely to survive for longer on a cold draining board than on a dry hanky.’
On the right kind of surface, viruses can survive for days.
The norovirus can live for up to four days on door handles, tables, handrails or computer keyboards, and even soft surfaces such as cushions, carpets, bedding or clothes.
Viruses normally get into the body via the hands into the mouth, or through rubbing your eyes or touching your face.
The importance of regular handwashing was highlighted by a U.S. report last week that found we touch our faces on average 3.6 times an hour.
If someone in your household has had norovirus, you need to regularly wash surfaces with disinfectant: a basic wipe down of surfaces with soapy water is not enough to kill the virus.
Sheets or clothes that could have been contaminated should be washed separately from other washing, and at 60 or 70 degrees.
The importance of regular handwashing was highlighted by a U.S. report last week that found we touch our faces on average 3.6 times an hour
IT TAKES SECONDS TO BE INFECTED
Depending on the virus, it can take just a few seconds to be infected (though, with some, it can take a couple of years).
It all comes down to the number of virus particles you need to pick up in order to become infected — and this varies with the virus.
‘With some, you need a smaller amount of what we call viral load than others,’ says Professor Jones.
For norovirus, you need exposure to only a small number of virus particles — between ten and 100 — to catch the sickness compared with 10,000 particles to catch flu.
‘You only need to come into contact with a single droplet from a sneeze — which can contain up to a million virus particles — to become infected with a cold,’ says Professor Jones.
‘But a virus such as HIV, which is spread by direct contact with blood, is relatively difficult to catch.
'It’s possible to have a married couple where one partner has HIV and for it to take a couple of years for the other partner to catch it.’
WHY ANTIBIOTICS ARE NO USE
The reason antibiotics don’t work against viruses is because bacteria and viruses operate in completely different ways.
Bacteria attach themselves to the outside of cells, while viruses get inside.
Antibiotics work by destroying the bacteria wall, so bacteria are therefore easier to target, says John Oxford, professor of virology at Queen Mary, University of London. ‘Once a virus gets into a cell, it inserts its own genetic material into the genes so the host cell becomes, in effect, a virus factory,’ adds Professor Oxford.
‘Within a day, one human host cell infected with norovirus, for example, will produce 10,000 to 20,000 virus cells and infect the surrounding cells.
'And this process will continue until the immune system starts to spot and destroy the infected cells.’
Anti-virals work in various ways. Tamiflu, used for flu, binds to the infected cell and stops it replicating — it stops a new ‘bud’ cell that’s been infected with the virus from breaking away.
That means it stops the virus from proliferating, which is why it needs to be taken at the early stage of the infection.
COULD A COLD TRIGGER DIABETES
Scientists are discovering that viruses can play a part in triggering other conditions.
Hepatitis C, for example, has been linked to type 2 diabetes.
A study of 10,000 people carried out in the U.S. found that those aged 40 or over who had suffered hepatitis C were three times more likely to develop type 2 diabetes — which is normally thought of as a lifestyle condition triggered by being overweight.
Viruses have also been linked to type 1 diabetes, an auto-immune condition. Children with the condition were 9.8 times more likely to have been previously infected with enterovirus (a common cause of the cold) than children who didn’t have diabetes, according to a study published by the BMJ online last year.
This followed an earlier study, published in the European Journal of Epidemiology, which suggested a child’s risk of developing type 1 diabetes increased if they had contracted several viruses, such as rubella and chicken pox.
VIRUSES THAT WILL HAUNT YOU
While the vast majority of viruses will be overcome by the immune system, some — such as the herpes simplex virus — are with you for life.
This causes cold sores, lies dormant and is reactivated by certain triggers, such as having a cold (when the immune system is under pressure) or being exposed to strong sunlight.
Chicken pox virus (varicella zoster) can lie inactive in nerve endings and go on to cause shingles in later life.
While you can develop an immunity to a virus, such as the norovirus or a cold, the strains are constantly evolving so this won’t last for long — perhaps 14 weeks with norovirus.
A REASON TO EMIGRATE
The vomiting viruses, colds and flu tend to peak in winter partly because people congregate inside, explains Dr Ron Cutler, director of biomedical science at Queen Mary, University of London.
‘Viruses can be picked up and passed on often as a result of poor hygiene — which often means people just not washing their hands,’ says Dr Cutler.
‘A get-together where people are in close contact inside — for example, a concert in a closed venue, or a church carol service — is the perfect environment for viruses to spread.’
He adds: ‘The problem with viruses is that in the first phase of infection there are no signs or symptoms — and this can last for days, although normally people are contagious at this stage so it can then be passed on to other people.’
Viruses also survive longer during winter weather, thanks to the lack of sunshine and the damp weather conditions, says Professor Jones.