LEADING scientists have suggested that the Ebola virus could have lain dormant in the body of a Scots nurse before being triggered by her immune system.
Pauline Cafferkey continued to battle for her life yesterday at the Royal Free Hospital in London as doctors said she remained in a critical condition.
Health teams have now identified 65 close contacts of the 39-year-old nurse, who are being monitored closely. Some 26 have been given an experimental vaccination.
Ms Cafferkey, from Cambuslang, South Lanarkshire, was taken to the specialist hospital on Friday after suffering an “unusual late complication” from the virus which she contracted in Sierra Leone in December.
The Royal Free said she remained “critically ill” in the isolation unit yesterday.
Dr Margaret Harris, World Health Organisation (WHO) spokeswoman, said the agency had heard of several similar cases, although they are not well documented.
“What we have seen is that in some people, the virus lies dormant at a site and then for some unknown reason, starts to reproduce again.
“We think it’s a minority of people, otherwise we would have seen cases all over the place.”
Dr Harris said it was unclear whether those people might then be infectious to others.
UK health officials have previously assured the public there is little risk of contagion.
Ebola has claimed the lives of more than 11,000 people in West Africa and left more than 17,000 survivors in the region.
Dr Harris said a significant number of recovered Ebola patients are still suffering ill-effects from the virus.
In some areas of Sierra Leone, half of the Ebola survivors have serious eye problems that only developed after they were discharged from the clinic.
Experts still have very little information about the impact of Ebola lingering in the body at different sites, she said, noting it was unclear whether the persistent virus might be responsible for survivors’ ongoing medical problems or if those can be attributed to the acute illness that patients recovered from months earlier.
Scientists say the Ebola virus can sometimes hide for months in parts of the body not covered by the immune system but acknowledged that Ms Cafferkey’s case was unusual.
“Pauline seems to be an anomaly,” said Dr Nathalie MacDermott, a clinical research fellow at Imperial College London.
“Everything we know about Ebola suggests there are long-term effects but not necessarily any that are life-threatening.”
Dr MacDermott said Ms Cafferkey’s relapse might have been triggered by her immune system. She added: “If the immune system is distracted, say by fighting off another infection, that might give the virus a foothold to start replicating again out of control.
“It is unusual that it would be able to spiral out of control and (produce) an acute infection again but it’s not impossible.”
Dr MacDermott said other diseases like herpes also recur when a person’s immune system is weakened, and said it was possible that similar cases to Ms Cafferkey’s were going undetected in West Africa.
Ms Cafferkey spent nearly a month at the Royal Free before she was discharged in January.
She was flown to London from the Queen Elizabeth University Hospital in Glasgow.