Canadian researchers thwart Ebola virus
A team of Canadian researchers has developed one of the most effective cures yet for the Ebola virus. That’s big news both for treating the deadliest virus on Earth and tackling myriad other similarly aggressive diseases.
The treatment, in which injections of protein-grabbing antibodies stop a virus from replicating, has the longest treatment window so far resulting in full recovery - a full day. There’s just one catch: It can take up to two weeks for symptoms of the disease to appear.
In an article published Wednesday in Science and Translational Medicine, Gary Kobinger and several others outline the cocktail of antibodies they used to treat macaque monkeys infected with the most lethal strain of Ebola virus. All the macaques treated 24 hours after infection recovered, as did half of those treated after 48 hours.
It’s big news for a notorious virus, which can kill up to nine of every 10 humans infected (the most virulent strains of flu, by comparison, kill about five of every hundred infected). Up until now, the best treatment was only good for less than an hour after exposure.
Ebola is a hemorrhagic fever most commonly found in Africa. In the past several years, it’s gone from fodder for horror novels to a concern for bio-security experts and public health officials alike. it becomes easier to synthesize or transport a virus and as global travel increases, the risk of an outbreak grows.
What Is the Ebola Virus?
The Ebola virus is a type of ribonucleic acid (RNA) virus that causes the disease known as Ebola hemorrhagic fever (also called Ebola).
How Did the Virus Get Its Name?
The Ebola virus was first recognized in the Democratic Republic of the Congo (formerly Zaire), in Africa, and got its name from a river there.
Subtypes of the Ebola Virus
There are two members of a family of RNA viruses called Filoviridae, and the Ebola virus is one of them. There are four identified subtypes of the virus. Three of the four have caused disease in humans:
- Ebola-Ivory Coast
- Ebola-Sudan
- Ebola-Zaire.
The fourth Ebola virus subtype, Ebola-Reston, has caused disease in nonhuman primates, but not in humans.
The Canadian researchers behind this treatment hope they can apply the same strategy to other viruses.
The Reston subtype of Ebola virus was first identified in 1989 in the United States in monkeys housed in a quarantine facility in Reston, Virginia. At least four humans became infected, but none became ill. Additional outbreaks of the Reston subtype occurred between 1989 and 1996 in Texas, Pennsylvania, and Italy. No humans suffered illness in any of these cases. The source of all the Reston subtype outbreaks was traced to a single facility in the Philippines that exported the monkeys. In July of 2009, the discovery of the Reston subtype in domestic pigs in the Philippines was reported. Genetic analysis suggests that the virus has been widely circulating in swine for many years, possibly even before the 1989 outbreak in the United States. The virus has been detected in farmers who have had contact with infected pigs, but they have not shown any signs of illness.
In late 2007, a fifth strain of Ebola virus emerged in western Uganda. The new species of the virus appears to be relatively mild, but officials at the World Health Organization are concerned about it because symptoms include vomiting, which is different from the other strains.
Where does the Ebola virus go in between outbreaks? As for other viruses, the survival of Ebola depends upon a host organism(s). Humans are not the host organism - or natural reservoir - of Ebola viruses. Humans become infected when they come into contact with an infected host, although once humans become infected they can transmit Ebola to other people. The identification of the natural reservoir of a virus is of great interest to scientists, because this knowledge gives information as to the geographic range and ecological areas where humans may come in contact with animals or insects that may be the source of the disease; this may allow scientists to more readily contain outbreaks.
In 2005 it was reported that fruit bats may serve as the natural reservoir of Ebola. Researchers trapped small animals found near Ebola-infected gorilla and chimpanzee carcasses over a period of time between 2001 and 2003. They found evidence that three species of captured fruit bats showed evidence of symptomless infection – that is the bats had Ebola-specific genetic sequences in their bodies or evidence of an immune response to Ebola even though they did not exhibit signs of the disease. Fruit bats live in regions of Africa that include areas where Ebola outbreaks have occurred and are eaten by people in central Africa. These animals may play a key role in transmitting Ebola to great apes and humans. Bats have been implicated as a reservoir of other viruses that cause deadly diseases including SARS and Marburg, a virus related to Ebola that also causes hemorrhagic fever.
“This is a leapfrog that brings everything forward,” said Dr. Kobinger, head of vector design and immunotherapy at Winnipeg’s National Microbiology Laboratory. “That’s why we’re so excited. … If we use the same technology, we can adapt it.”
The treatment is a new take on an old method: Researchers produced three antibodies designed to bind to different proteins on the Ebola virus’s outer coat. The antibodies are administered in three injections – one after 24 hours, one on Day 3 and one on Day 5.