Atlanta, US (BBN)-The Ebola virus has been detected in the eye of a US doctor who had already recovered from the illness.
The medic, who caught the bug while working in Sierra Leone, had blurred eyesight and pain two months after being declared Ebola-free.
Scientists say his eye infection presents no risk to the public, reports BBC.
But reporting in the New England Journal of Medicine they warn that research is needed to see if Ebola can also linger in other parts of the body.
INFLAMMATORY REACTION
Patients with Ebola are generally discharged once tests show the virus is no longer present in blood. At this point, experts say, it cannot be spread to members of the general public.
But there have been suggestions the virus may live on in some bodily fluids as certain parts of the body could act as reservoirs.
Now a team, including scientists from Emory University School of Medicine, say Ebola can persist in the eye and lead to further damage.
Their 43-year-old patient recovered from a serious Ebola infection that needed weeks of intensive care.
But shortly after being discharged, he had a burning sensation in his eyes and suffered worsening blurry vision.
Tests showed the fluid in his left eye had live Ebola virus.
And doctors say there was widespread inflammation which can lead to blindness.
But after three months of treatment with steroids and antiviral drugs, his vision began to improve.
Experts think the virus's staying power might be due to the eye's ability to tolerate certain pathogens once inside its walls.
They suggest further studies are warranted to check for the the presence of the virus in other "immune privileged" sites such as the central nervous system, testicles and cartilage.
And doctors are calling for more help for survivors in the worst-affected countries. Recovering patients are reporting eye problems among other difficulties.
But eye specialists are in short supply in Sierra Leone, Guinea and Liberia.
Dr Russell Van Gelder, of the American Academy of Ophthalmology, said: "This remarkable case now demonstrates that the virus can remain viable in ocular fluids long after the patient has recovered from the systemic infection.
"If the Ebola epidemic continues, ophthalmologists throughout the world will be seeing patients with post-Ebola uveitis (inflammation), and will need to recognise and treat this condition.
"However, I want to emphasise that as far as we know, the Ebola virus is not transmitted by casual contact.
"The current study does not suggest that infection can be transmitted through contact with tears of patients who have recovered from their initial infection."
SAFE SEX
Separately, the World Health Organization (WHO) has strengthened its safe sex advice for survivors.
A recent case suggested Ebola fragments could remain in the semen of male survivors some months after recovery.
This, alongside evidence gathered from similar viruses, led WHO experts to warn there is a "strong possibility" Ebola could be passed on from male survivors to females during sexual contact.
This has not yet been proven.
But the organisation now advises all recovered patients and their partners to abstain from or practise safe sex until male survivors have had two negative semen tests.
WHO scientists add it is not clear whether female survivors can transmit the virus through sexual contact. But they caution it remains "theoretically possible".