The Ebola virus, which has caused deaths from high fever and bleeding in African outbreaks, can also infect without producing illness, according to a new finding by African and European scientists.

The possibility of asymptomatic infection was only suggested in earlier studies, they said in last week's issue of The Lancet, a medical journal published in London. Now they said they had documented such infections for the first time. They found that the Ebola virus could persist in the blood of asymptomatic infected individuals for two weeks after they were first exposed to an infected individual. How much longer the virus can persist is unknown.

All outbreaks of Ebola have been controlled by standard infection control measures such as effective body disposal, destroying or sterilizing contaminated equipment and appropriate use of gloves. But if people can be carriers without showing symptoms, it means control might be more difficult.

''This degree of containment would be virtually impossible if symptom-free carriers posed a significant threat of infection,'' Dr. Alan G. Baxter of Newtown, Australia, wrote in an editorial in the same issue of The Lancet.