HEALTH workers returning from ebola-stricken countries should always be tested for the virus if they ever become unwell, the scientist leading Britain's fight against the disease said at the weekend.

Professor Tom Solomon also said that the plight of the Scottish nurse, Pauline Cafferkey, indicated that there was inadequate testing for volunteers who had worked in countries afflicted with ebola.

Ms Cafferkey, 39, is still being treated in London's Royal Free Hospital, after suffering an apparent relapse following her return from Sierra Leone at the end of last year.

The hospital issued a statement last Wednesday saying her condition had deteriorated and she was critically ill. A hospital spokesman said yesterday that this remains the case.

Sixty-five people who had come into contact with Ms Cafferkey, among them colleagues and friends, have been traced, with 26 vaccines being issued as a precautionary measure.

Prof Solomon, director of the Institute of Infection and Global Health at Liverpool University, was reported as saying that all doctors and nurses who had worked in epidemic-hit nations should undergo testing for ebola if they fell ill, even if this happened months afterwards and they showed no symptoms of the virus.

He said: "If someone has been back [from an ebola-affected area] for months and is apparently unwell, when they become unwell again your first thought would not be 'let's check for ebola' but clearly now that will have to be on the agenda.

"What's happening with Pauline has shown us that we have to remain vigilant and we will have to remain more careful if someone has been previously infected and they appear to be unwell with something else."

He added: "We have a small number of people now in the UK who have had ebola and recovered. I guess if they have any other illness our approach will have to be a bit different. We have to think, 'Could this be ebola again?'"

But he cautioned against "over-reactions" and pointed out that it was still unclear whether Ms Cafferkey was suffering from an ebola relapse or something else. There has been speculation that she may be suffering from meningitis.

Ms Cafferkey, from Cambuslang, in south Lanarkshire, was taken unwell and was treated at Glasgow's Queen Elizabeth University Hospital before being was flown in a military aircraft and transferred to the Royal Free in London.

She had initially gone to an out-of-hours doctor in Glasgow but was sent home after being told she probably had a virus. Her family has alleged that doctors "missed a big opportunity" to spot she had fallen ill again

Health Protection Scotland, part of the NHS, said at the weekend that the recurrence of the health worker's ebola infection into a severe life-threatening illness "is something new and literally a world first."

Since her diagnosis last year and subsequent discharge from hospital, it added, she had been intensively followed up by infectious diseases specialists in Glasgow in collaboration with their counterparts at the Royal Free Hospital.

It said that little was known about the long-term complications of the disease as earlier outbreaks had happened on a much smaller scale with only a few cases to guide clinicians. As more was discovered about the complications, NHS Scotland and other countries would develop "appropriate protocol and care plans."