Ebola: Experimental treatments
By Helen BriggsHealth editor, BBC News website
Ebola virus under the microscopeAn experimental treatment for Ebola has reportedly shown some signs of success in a US aid worker. What potential treatments for Ebola might be available in the future?
What is the current treatment for Ebola?There is no licensed treatment or vaccine for the Ebola virus. Hospital treatment is based on giving patients intravenous fluids to stop dehydration and antibiotics to fight infections. Strict medical infection control and prompt burial are regarded as the best means of prevention.
What new treatments are being tried for Ebola?A couple of experimental treatments have been used on a compassionate basis. The approach is based on the idea that antibodies against the Ebola virus might help the body fight off the infection. An antibody is a protein produced by the immune system in response to harmful invaders, such as viruses.
What is serum?Serum is the part of the blood that contains antibodies. In past Ebola outbreaks, serum has been taken from people who have survived Ebola but are no longer infectious. Their blood still contains high levels of antibodies against the virus. In one outbreak in 1995 in the Democratic Republic of Congo, seven out of eight patients survived after being treated with serum, according to Prof Tom Solomon, director of the NIHRHealth Protection Research Unit in Emerging and Zoonotic infections. Reports suggest that a US aid worker who developed Ebola may have been given serum before being flown home from Africa.
What are monoclonal antibodies?An experimental cocktail of three engineered antibodies against the Ebola virus has been developed. The treatment is not yet licensed as it has not been tested in clinical trials. The antibodies were originally harvested from mice that had been injected with parts of the Ebola virus. They have been adapted to work in the human body and can be manufactured in the tobacco plant.
Experiments on monkeys suggest the antibody cocktail may reduce fatalities when given after exposure to the virus. Two US aid workers have reportedly been given this experimental treatment, known as Zmapp, with "apparently encouraging" signs in one of them, said Prof Solomon.
What other approaches are being tried?There are a couple of prototype vaccines against Ebola, but these are in the very early stages of research in animal models. Nothing is licensed and clinical trials would be very difficult to conduct.
The natural host for the virus is the fruit batThe Food and Drug Administration in the US says it is fast-tracking a vaccine that has shown encouraging signs in monkeys for phase 1 trials in September.
This type of trial is the earliest study in humans and aims to make sure that drugs are safe and show some chance of working.
Another area of research is looking into how the Ebola virus triggers severe internal bleeding. The aim would be to boost clotting factors that the body produces naturally to control bleeding.
What are the chances of success?Experts say that pharmaceutical companies are unlikely to invest the huge resources needed to develop new drugs when these would likely be used only occasionally in relatively small numbers of people. They say investment is needed from international agencies to have any realistic chance of success in the future.
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