Health officials in French Polynesia say about half of those who have contracted the mosquito-borne disease chikungunya face recurring symptoms several weeks after their initial infection.
The outbreak in Tahiti has affected about 130,000 people, or half the population, in the three months since its start and to date nine deaths have been attributed to the illness.
A doctor, Henri-Pierre Mallet, has told local media that a growing number of people are seeking medical care because they are again experiencing the same types of pain and discomfort.
He says these patients have not been re-infected but feel the persistence of the virus, which can produce similar symptoms again.
Based on observations made in other parts of the world, Dr Mallet says elderly patients risk developing a chronic form of chikungunya-related pain.
And he also warns that with a mortality rate of one per 4,000 chikungunya patients, French Polynesia is at risk of seeing dozens of people dying form the latest outbreak.