THE norovirus has effectively brought one of the largest hospitals in south-east London to its knees. SCOTT MULLINS finds out why.

At this time of the year, the NHS is fighting a constant battle with a norovirus like the one that has forced the closure of the Princess Royal University Hospital, Farnborough.

The country's health service says noroviruses are part of a group of viruses that are the UK's most common cause of gastroenteritis, otherwise known as an upset stomach.

Noroviruses are sometimes known as small round structured viruses (SRSVs) or Norwalk-like viruses. Noroviruses are also called the winter vomiting disease because people usually get them during the winter months.

However, they can occur at any time of the year.

It is estimated the norovirus affects between 600,000 and one million people in the UK every year.

Outbreaks of the illness are common, particularly within contained environments such as hospitals, nursing homes and schools.

This is because the norovirus spreads very easily from person to person and it can survive for several days in a contaminated area.

The norovirus can be spread through contact with an infected person, through contact with surfaces or objects that are contaminated with the virus, or by eating contaminated food or water.

There are many types of norovirus, and it is possible for infection to occur several times.

This is because after getting the illness immunity to the virus only lasts for 14 weeks.

Having recurring bouts of the norovirus may provide some protection from future infection.

(Source: www.nhs.uk)