Canadian researchers thwart Ebola virus
Once the antibodies have glommed on to the Ebola’s protein coat, they slow it down and prevent it from replicating. This buys the immune system time to build a response and eradicate the virus.
“It’s encouraging,” said Gary Nabel, director of the U.S. National Institute of Health’s vaccine research centre in Bethesda, Md. “It’s an unusual finding in that there have been other studies using antibodies that have failed to protect. They’re using a cocktail of antibodies that seem to be doing better.”
Where do cases of Ebola hemorrhagic fever occur?
Confirmed cases of Ebola HF have been reported in the Democratic Republic of the Congo, Gabon, Sudan, the Ivory Coast, and Uganda. An individual with serologic evidence of infection but showing no apparent illness has been reported in Liberia, and a laboratory worker in England became ill as a result of an accidental needle-stick. No case of the disease in humans has ever been reported in the United States. Ebola-Reston virus caused severe illness and death in monkeys imported to research facilities in the United States and Italy from the Philippines; during these outbreaks, several research workers became infected with the virus, but did not become ill.
Ebola HF typically appears in sporadic outbreaks, usually spread within a health-care setting (a situation known as amplification). It is likely that sporadic, isolated cases occur as well, but go unrecognized.
How is Ebola virus spread?
Infection with Ebola virus in humans is incidental - humans do not “carry” the virus. Because the natural reservoir of the virus is unknown, the manner in which the virus first appears in a human at the start of an outbreak has not been determined. However, researchers have hypothesized that the first patient becomes infected through contact with an infected animal.
After the first case-patient in an outbreak setting (often called the index case) is infected, humans can transmit the virus in several ways. People can be exposed to Ebola virus from direct contact with the blood and/or secretions of an infected person. This is why the virus has often been spread through the families and friends of infected persons: in the course of feeding, holding, or otherwise caring for them, family members and friends would come into close contact with such secretions. People can also be exposed to Ebola virus through contact with objects, such as needles, that have been contaminated with infected secretions.
Dr. Nabel noted, however, that it’s difficult to imagine how a complex treatment requiring multiple injections like this would translate into a more volatile outbreak setting.
Dr. Kobinger’s next challenge is to push that 24-hour window to 72 hours. The tricky thing about treating Ebola is that it has a 10-day incubation stage: By the time a person starts to show symptoms, it’s too late.
But 72 hours after infection, doctors can detect the virus in the blood – a trigger for treatment. A cure that was effective after that point would be much more useful.
Preliminary results suggest the Winnipeg-based researchers might be able to do that by combining this triple-antibody treatment with an Ebola vaccine they’re working on. The two together could make for an effective cure days after infection.
On a pragmatic level, getting this research published in a well-regarded journal could make it easier for Dr. Kobinger to ask for continued government funding in a cash-strapped environment.
The Department of National Defence has funded much of his research so far, but has indicated in this year’s budget it may cut back on anything except but Arctic security and cybersecurity.
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ANNA MEHLER PAPERNY
The Globe and Mail