India has quarantined a man who was cured of Ebola in Liberia because of the possibility that he may spread the virus through sex.
The man tested negative for Ebola in standard checks when he arrived at Delhi airport.
However, officials said he was being quarantined because the virus was still present in his semen - and could be transmitted by the "sexual route".
Ebola has killed more than 5,000 people this year, mostly in West Africa.
Most of the cases in the latest outbreak - the deadliest ever - have been recorded in Liberia, Guinea and Sierra Leone.
Men who have been successfully treated for the disease are advised against having sex - or to make sure they use a condom - because their semen can still carry traces of the virus for up to 90 days after they have been cured.
The Indian Health Ministry said the man, a 26-year-old Indian national, had arrived in the country on 10 November.
He had been carrying documents with him that stated he had been successfully treated for Ebola in Liberia.
He was tested for the disease according to the guidelines of the World Heath Organization (WHO). No traces of the virus were found - effectively confirming that he had been cured.
According to a government press release, however, the man was isolated at Delhi airport "as a matter of abundant caution".
Semen samples were then taken, which tested positive for the virus.
The ministry said the man would be kept in isolation until the virus was no longer present in his body.
Many experts fear Ebola could wreak havoc if it reached India because of poor public hygiene and the lack of basic health services in many areas.
There are nearly 45,000 Indian nationals living in West Africa, according to the Reuters news agency.