New York: Researchers are a step closer to developing a broadly effective antibody treatment against the three major Ebola viruses that cause the lethal disease in humans.

The study found that the isolation of two potent monoclonal antibodies from human survivors of Ebola virus disease that -- in cell culture studies -- efficiently neutralised the Zaire, Sudan and Bundibugyo ebolaviruses.

The antibodies -- EBOV-515 and EBOV-520 -- also showed the capacity to protect against infection by these viruses in animal models.

"Our team was very excited to discover these new antibodies that have the capacity to treat all ebolaviruses. They appear very promising for development as a treatment and prevention for Ebola virus disease," said co-author James Crowe Jr from the Vanderbilt University School of Medicine in the US.

Ebola virus disease, which was first reported in Central Africa in 1976, can cause massive bleeding.

The death rate is about 50 per cent and the virus is spread by contact with contaminated body fluids, including blood and semen.

A major outbreak in West Africa claimed more than 11,000 lives between 2014 and 2016.

Earlier this month, the World Health Organization (WHO) reported 29 deaths from a smaller outbreak that began in April in the Democratic Republic of the Congo.

While further study is needed, these antibodies could lead to development of injectable antibody "cocktails" for people at high risk of being infected by Ebola viruses, the researchers said.

The hope is that the antibodies -- like heat-seeking missiles -- would seek out and destroy the viruses before they can wreak havoc in the body, they said.

For the study, plasma was obtained from survivors of Ebola virus disease outbreaks in the Congo and West Africa.

Monoclonal antibodies were generated from the white blood cells of two survivors that showed the highest activity against the three Ebola viruses.