One case of swine flu has been confirmed at Cork University Hospital (CUH).

It is one of a number of flu-like cases at the hospital. However the H1N1 strain has only been confirmed in one patient.

The Health Service Executive (HSE) says visitor restrictions have been enforced and anyone with flu-like symptoms are being asked to stay away.

"It is important to realise that H1N1 is no different from other strains of flu in regards to the principles of creating a vaccine to protect against it", the HSE said in a statement.

Hospital management say they are continuing to monitor the situation.

This virus was originally referred to as 'swine flu' because laboratory testing showed that many of the genes in the virus were very similar to flu viruses that normally occur in pigs (swine) in North America.

The swine flu virus, as seen through an electron micrograph (Image: Centres for Disease Control and Prevention)

But further study has shown that the H1N1 is very different from what normally circulates in pigs.

It has two genes from flu viruses that normally circulate in pigs in Europe and Asia, as well as bird (avian) genes and human genes. Scientists call this a "quadruple reassortant" virus.

The US Centres for Disease Control and Prevention (CDC) says the virus can spread from person-to-person, probably in much the same way that regular seasonal flu viruses spread.

Back in June 2009, the World Health Organization (WHO) declared that a pandemic of H1N1 flu was underway.