Scientists in Canada announced the successful treatment of Ebola viral infection in monkeys. The encouraging results were published in the journal Science Translational Medicine on June 13.
Researchers from the National Microbiology Laboratory in Winnipeg, Manitoba identified a number of antibodies that corresponded to proteins on the shell of the Ebola virus. They combined the antibodies into a specific cocktail and administered it to four macaques within 24 hours of infection. All four macaques survived. When the cocktail was administered within 48 hours of infection, two of four macaques survived.
Why is the survival of a few monkeys such big news? Ebola hemorrhagic fever, a disease caused by infection with the Ebola virus, is one of the most deadly and little-understood diseases in the world. There is no vaccine, no standard treatment, and the origin of the virus remains unknown.
Your cheat sheet on Ebola virus
Ebola virus was first recognized in 1976 in Zaire (now the Democratic Republic of Congo) in an outbreak that affected 318 people and resulted in 280 deaths. The virus and its five subtypes belong to a family of viruses called Filoviridae; only four of the five subtypes have caused disease in humans. The virus affects humans and non-human primates, but the natural reservoir of Ebola remains unknown. This means the exact origin and natural habitat of the virus are a mystery, with significant implications for treatment and prevention.
Scientists believe Ebola spreads through zoonotic transmission- that is, coming from an animal. The first patient of an Ebola outbreak is thought to be infected through contact with an infected animal. From there, the virus can spread to other humans through direct contact with blood or body fluids. Outbreaks often occur in healthcare settings (known as nosocomial transmission), as patients seek treatment in facilities where appropriate infection-control may not be practiced. The symptoms of Ebola are somewhat nonspecific at first. Within 2-21 days of exposure, patients usually experience fever, headache, joint and muscle aches, sore throat, and weakness, later followed by diarrhea, vomiting and stomach pain. Some patients also experience rash, red eyes, hiccups and bleeding. From the onset of symptoms, Ebola can kill a patient within a matter of days.
There is no known treatment for Ebola in humans. Doctors can offer supportive therapy, such as hydration, oxygen and treatment of complicating infections, but mortality rates are still very high. Because the natural reservoir and origin of transmission remains unknown, there are no established methods of primary prevention. Instead, prevention efforts focus on outbreak control in healthcare settings.
There have been 28 documented outbreaks, with 2,288 human cases and 1,331 deaths. The most recent Ebola outbreak, according to the CDC, was a single case in Luwero district, Uganda in May 2011.
A cure for human Ebola infection? Not just yet.
What does this recent advance mean? Can we expect a post-exposure treatment for humans? Or better yet, a vaccine? Scientists caution this is certainly a big step forward, but many challenges remain before the treatment can be applied to an outbreak in humans. For example, the amount of antibodies needed to treat a larger group of people would be difficult to manufacture.
For a first-person account of the initial detection of the Ebola virus, listen to this interview from NPR’s Talk of the Nation with Peter Piot, a member of the 1976 team who first identified Ebola, as he discusses his memories of the discovery and his long career in virology.