THREE patients have been quarantined after an outbreak of the potentially deadly 'superbug' MRSA at Dorset County Hospital.

The Purbeck orthopaedic ward at the Dorchester hospital has been closed for a week to be disinfected after the three patients tested positive for the virus.

MRSA - methycillin resistant staphylococcus aureus - is commonly found in more than one in four people in the community and becomes dangerous in vulnerable patients suffering from a debilitating disease.

It manifests itself in weeping sores, is resistant to most antibiotics and spreads in epidemics.

The virus is caused by the bacterium staphylococcus aureus, which is easily spread among hospital patients, which means that operations on patients infected by MRSA have to be cancelled.

There are two types of antibiotics used to treat the virus when a person becomes infected, but they have to be delivered intravenously and can be toxic.

West Dorset General Hospitals NHS Trust chief executive Nick Chapman said: "We reopened the ward yesterday after doing a deep clean, disinfecting everything and isolating patients.

"The MRSA virus is present in the community at large and it is something that we are always on our guard against.

"That is why we pick these things up quickly. Three patients have tested positive for the virus and they are now being treated."

Hospital staff are urged to wash their hands before and after dealing with each patient to try to minimise the risk of spreading the virus and prevent outbreaks.

After someone has tested positive for MRSA they are isolated in a room with the door shut to stop the virus spreading and as carriers of the virus they have to be isolated if they are admitted to hospital in the future.

Mr Chapman said the county hospital had two orthopaedic wards, Purbeck and Ridgeway, but staff caught the virus in time to stop it spreading to the Ridgeway ward.

The hospital has suffered regular outbreaks of the virus over the past few years after the 'superbug' developed a resistance to antibiotics. Patients are put at greater risk if they develop the virus after an operation or while on an intravenous drip. They may develop skin infections, urinary tract infections, pneumonia and blood poisoning.