Help needed. that the new treatment can benefit patients such as Ebola victim of this epidemic in the Democratic Republic of Congo in 07 remains to be seen.
World Health Organization
When a German scientist accidentally pricked herself with a needle containing the Ebola Zaire virus last year, scientists from around the world tried to determine what the best course of action would be. Finally, she agreed to an experimental Ebola vaccine that has been shown in animals to provide about 50% protection, even when administered after exposure to the virus. And she lived
But now scientists say they have something better for these mishaps :. A new therapy that, in laboratory studies, offered complete protection to cynomolgus monkeys when administered daily for nearly a week after injection Ebola otherwise be fatal. The new treatment, which will be reported online tomorrow The Lancet , could also be used in Ebola outbreaks, the researchers say.
Although Ebola outbreaks are quite rare, macabre symptoms- including high fever, bleeding and vomiting, and the rate of up to 0% mortality have captured the worldwide attention and helped propel the virus on the list of potential bioterrorism threats.
lead author of the new study, virologist Thomas Geisbert of Boston University School of Medicine, who worked on the Ebola virus for over 20 years, said that drug development has been slow and difficult. An anticoagulant that Geisbert helped test against the virus was received with great enthusiasm when he presented the results 7 years ago because it was the first time a drug had much impact and deaths but not reduced in monkeys by a third party.
For the new study, Geisbert and colleagues have used extracts of so-called small interfering RNA (siRNA), which can tinker with the replication of a virus. These siRNAs are considered a great promise against viral diseases, but a key issue is that they break down easily inside the body. To avoid this, the team packed siRNA inside particles called stable nucleic acid-lipid (SNALPs). Developed by Canadian biotech company Tekmira Pharmaceuticals, these particles are supposed to protect the drugs and help them reach the cells infected by the Ebola virus. In a study published in 06, the group showed that Geisbert SNALPs containing siRNA targeting a protein called Ebola L polymerase completely protected guinea pigs infected Ebola death.
But primates are much more vulnerable to Ebola, so in the current study, the group added two more siRNA. They injected cocktail intravenously in three monkeys to 30 minutes after exposure to the virus, then 1, 3 and 5 days later; two of them survived. In a group of four macaques that received the treatment 30 minutes and one day, two, three, four, five and six after the exposure, all survived.
Geisbert said more work is needed, for example, to determine the optimal dose and contribution to the overall effect of all three siRNA. That treatment also works after the animals get sick really remains to be seen as well; which is difficult to test in monkeys because animals die very quickly after infection, he said.
Nevertheless, the study is an important proof of concept, said Heinz Feldmann, an Ebola researcher at the National Institute of Allergy and Rocky Mountain Laboratories of Infectious Diseases in Hamilton, Montana. The new treatment offers the best protection ever seen when administered after exposure to the virus, he said.
Feldmann helped developed the vaccine given by the German researcher. But he said that the new treatment will probably be preferred, not only because it is more efficient, but also because, unlike the vaccine, it is not based on a replicating virus livestock. These vaccines always raise additional safety concerns.
It is important to Geisbert and other compounds now being tested and developed, Feldmann said, so the treatment is on the shelves the next time a researcher or health worker himself spades. "It's been a year since the accident in Germany, and we still do not have anything," he said. "We are in a terrible situation."
The complicated treatment regimen and that treatment must begin shortly after exposure may limit the use of the compound of Geisbert in remote areas in Africa where Ebola outbreaks occur. However, Feldmann, who worked in several of these epidemics, hope the treatment can be used as well. the current strategy is to take care of patients as well as possible and break the chain transmission by preventing others from infection. "as an MD, I would do something for the patient as well," he said.
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