A US Army physician assistant checks out a Ugandan boy earlier this year. Photo: US Navy Petty Officer 1st Class Tom Ouellette
Ebola virus is one of those diseases that they make horror movies out of—with the on-screen results needing little sprucing up to successfully terrify everyone. Until now, there's been little progress on preventing or treating Ebola, but US Army researchers may have just taken the first step in the right direction.
In humans, Ebola causes severe hemorrhagic fever (and bleeding from mucous membranes) and has a 90 percent kill rate. It's been pointed to by the as a "high-priority public health threat" by the US government and as a category A (the worst) bioterrorism threat by the Centers for Disease control.
Sporadic outbreaks in Africa have generally killed hundreds each time it's happened. In late 1989, an outbreak of the similar Reston virus near the Washington, DC suburb of the same name scared the hell out of everyone, but that outbreak was limited to monkeys. Most recently, outbreaks in 2012 killed 17 people in Western Uganda and 34 people in the Democratic Republic of the Congo. Ebola is so deadly because it has an unusually high replication rate. It often takes just days to go from infection to death.
But a treatment, known as MB-003 by researchers at the US Army Medical Research Institute of Infectious Diseases, might give us some hope of fighting it. In a test with macaques, of those given MB-003 within an hour of Ebola infection, 100 percent lived.
It was the first time that scientists were able to successfully treat cases of Ebola after visible symptoms and a positive lab test had occurred.
That timeline is not going to be feasible in an outbreak scenario, so they pushed the window back further: Two thirds survived when treated within 48 hours, and 43 percent survived when given the "antibody cocktail" four days after exposure.
MB-003 works by pumping the body full of a huge number of antibodies, which supplement the victim's natural immune system response, which is almost always too slow to save them on its own. Macaques who received the treatment didn't show any side effects from the drug.
A less-than-50-percent survival rate doesn't seem all that high, but it was the first time ever that scientists were able to successfully treat cases of Ebola after visible symptoms and a positive lab test for Ebola had occurred. Every member of an untreated control group died.
"By requiring both a documentable fever and a positive diagnostic assay result for Ebola infection before initiating treatment in these animals, we were able to use MB-003 as a true therapeutic countermeasure," said Gene Olinger, an author of the study, which was published in Science Translational Medicine. "These initial results push the threshold of MB-003 from post-exposure prophylaxis to treating verified illness."
In a real outbreak scenario, the researchers say that exposure alone, given that there were no side effects from MB-003, would likely be enough to treat a patient.
"The requirement of [having both a fever and a positive diagnostic test] in this study was likely more stringent than would be required for therapy during a known outbreak where detection of [the virus] would be sufficient to initiate treatment," they write.
Though more testing is needed before the drug is approved for use in humans, in an outbreak scenario, MB-003 could be ready to go in as little as two weeks, according to the company the Army asked to make it. And right now, it represents the best option we have.