Hepatitis C tests are being offered to women who were treated at a Northern Ireland maternity unit more than 30 years ago, it has been revealed.
The Public Health Agency said it has been made aware that a former employee of the Mid Ulster Hospital, on the outskirts of Magherafelt, Co Londonderry has been diagnosed with the virus.
The staff member was employed at the Mid Ulster maternity and gynaecology units from January 11, 1979 to November 4, 1979 but did not work in any other hospital in Northern Ireland or the Republic.
Dr Lorraine Doherty, assistant director health protection, at the PHA, said the risk of infection was low.
"I want to emphasise that the risk of infection is very small and that the Northern Trust is offering testing, as a precaution, to anyone who believes they may have been treated in the maternity and gynaecology unit of the Mid Ulster Hospital during the relevant time period.
"Effective treatments are available for hepatitis C and further information and advice will also be provided to anyone who needs it," she said.
Around one in 250 people carry the hepatitis C infection in the UK. The virus was only identified in 1989 and a test was not developed until 1991.
It can affect the liver but in most cases there are no noticeable symptoms until the liver has been significantly damaged.
Transmission through contact with an infected healthcare worker is extremely rare and can only occur if they lead, or assist in, an operation on a patient.
Dr Doherty added: "I t does not automatically lead to health problems. It is very rare for a healthcare worker infected with hepatitis C to pass on the infection to a patient, but in this particular case there is a very slight chance that a patient might have been infected with the virus. This could only happen during some surgical procedures, not during any other care."
Anyone who is concerned is asked to contact a helpline set up by the Northern Health and Social Care Trust on 028 9442 4804. The line is open seven days a week from 8.30am to 8.30pm.