MORE than 5,000 women treated at a former Gwent hospital will be offered a hepatitis C test after it was discovered that a healthcare worker there unwittingly infected two patients.

Letters offering tests are being sent to women who had obstetric and gynaecological treatments at Caerphilly District Miners' Hospital during 1984-2003, when the now retired healthcare worker - who was unaware of having the disease - was employed there.

Hepatitis C is a blood borne virus that can cause liver disease and very rarely, liver cancer. In most cases, it does not have any symptoms.

The letters - from Aneurin Bevan University Health Board - will ask women whose treatment involved, or may have involved, the healthcare worker to telephone a dedicated helpline to arrange an appointment in a specialist nurse clinic.

A summer-long trawl of health records has identified women whose treatment involved the healthcare worker - who is not being named - in potential blood-to-blood contact.

Clinics will begin on Friday, September 13. Those taking up the offer can expect to receive their results in around two weeks.

"We know this will be a worrying time for those patients who will be contacted by letter, but we want to stress that the risk of transmission is low," said Dr Gill Richardson, the health board's director of public health, who confirmed that those being contacted are "exclusively women."

"As a precautionary measure, patients who may have been at risk of being exposed to the virus have been identified, and will receive a letter to attend a clinic, so we can ensure they are offered testing.

"Specialist nurse clinics have been set up, and we will do all we can to support patients.

"As many as one in 250 people carry hepatitis C infection and it does not automatically lead to health problems.

"Treatment can help clear the infection in up to 80 per cent of cases, which is why it is important to identify anyone who may be at risk of having been infected, so treatment can be started if necessary."

The infected worker retired from the NHS more than a decade ago and did not know they had the virus, diagnosis being made only after their retirement.

The potential link with former patients was made when the retired worker was receiving treatment. The health board was informed last November but no action was advised at that stage as there was then no evidence of transmission or ongoing risk.

Only when the first transmission was confirmed in May did the health board, advised by the UK Advisory Panel on Blood Borne Viruses, start to investigate.

The period covered for Caerphilly District Miners' Hospital patients is May 1984-June 2003. Smaller numbers of patients whose treatment at Wrexham Maelor Hospital (May 15-June 27 1978) and at the former East Glamorgan Hospital in Pontypridd (May 28-July 17 1984) also involved this healthcare worker, will also be contacted by their health boards, as will some patients in England, Scotland and Northern Ireland treated during the 1970s.

In all, around 5,500 patients will be contacted.

HEPATITIS C is a virus which can cause inflammation of the liver and if untreated, chronic liver disease and very rarely, liver cancer.

It was only discovered in 1989, and a test was introduced in 1991.

The virus is transmitted through blood-to-blood contact and very rarely through sexual intercourse.

The most common route of transmission in the UK is intravenous drug use. It cannot be transmitted through social contact, kissing, or sharing food and drink.

About four in every 1,000 people in the UK may carry the virus.

Some infected patients can become carriers, but treatment helps clear it in up to 80 per cent of carriers. That is why it is important to test the blood of patients who may be at risk of having been infected.

Since 2007, all healthcare workers new to the NHS should be offered a hepatitis C test, and anyone performing surgical procedures should be tested by their employing health board. Existing NHS healthcare workers performing such procedures for the first time should also be tested.

* More information on hepatitis C is available on the Aneurin Bevan University Health Board website at www.aneurinbevanhb.wales.nhs.uk and from the Hepatitis C trust at www.hepctrust.org.uk

Advice and information is also available for anyone with general concerns, from NHS Direct on 0845 46 47.

SINCE the health board began its investigation in May, tens of thousands of patients' records and details of surgical procedures and births at Caerphilly District Miners' Hospital have been checked.

"An awful lot of staff have worked extra hard over the summer, checking both electronic and handwritten records stretching back almost 30 years," said Dr Gill Richardson.

The detective work has been vital, because of a need to identify only patients whose treatments would indicate they were potentially at risk.

Health board chief executive Dr Andrew Goodall stressed that not every woman who received obstetric and gynaecological treatment at Caerphilly District Miners' Hospital, and involving this healthcare worker, during 1984-2003, is deemed at risk.

"If people do not get a letter, there is no need to worry," he said.

The predominantly blood-to-blood transmission of hepatitis C means mainly patients who underwent major surgery - such as caesarian sections, hysterectomies and ovary removals - are deemed at risk.

Dr Goodall also stressed that no blame should be placed on the healthcare worker, as they did not know how or where they picked up hepatitis C and were unaware they had it until after they retired.

Given the timescales involved, and because the disease was only discovered in 1989, it is possible the healthcare worker was infected before it was known that hepatitis C existed.