A gene-silencing treatment using tiny pieces of RNA to target Ebola virus protected monkeys given massive doses of the deadly pathogen. The findings, by researchers at Boston University School of Medicine in Massachusetts, the US Army Medical Research Institute in Fort Detrick, Md, and Tekmira Pharmaceuticals in Burnaby, BC, Canada, suggest the therapy will also protect humans (Geisbert TW et al. Lancet. 2010;375[9729]:1896-1905).
Mortality rates from outbreaks of hemorrhagic fever caused by Ebola virus in Africa have ranged from 25% as high as 90%.
Grahic Jump Location
Ebola virus infection has mortality rates of up to 90%; researchers hope a treatment that successfully protects monkeys exposed to the virus will ultimately work for humans.
In previous work, the researchers found that this approach, using small interfering RNAs (siRNAs) formulated in stable acid-lipid particles to foil Ebola virus replication, was successful in protecting guinea pigs against Ebola virus. But a rodent model does not necessarily predict how well a treatment will work in primates, including humans. In the current study, in rhesus macaques, the researchers improved on their methods by using the siRNA that protected in guinea pigs plus additional siRNAs targeting 2 other genes, with the aim of inactivating the virus at 3 different stages of its life cycle.
The researchers exposed 9 monkeys (2 were controls) to the Zaire strain of Ebola virus. After exposure, 3 of the monkeys were given intravenous infusions of the siRNAs at 30 minutes postexposure and again on days 1, 3, and 5; 4 monkeys were treated at 30 minutes postexposure and on days 1 through 6. Two of the 3 monkeys receiving 4 postexposure treatments survived and all of those receiving 7 postexposure treatments survived. A control monkey given no treatment died as did the other control monkey given 7 treatments with nonspecific modified siRNAs.
The investigators, while acknowledging further research is needed, suggest that RNA interference may be an effective postexposure treatment strategy for humans infected with the Ebola virus and may be a useful weapon for the treatment of other emerging viral infections.
In the meantime, however, the “specialty of haemorrhagic viruses is in desperate need of approved countermeasures against Ebola-virus infections,” noted Heinz Feldmann, MD, PhD, chief of the Laboratory of Virology at Rocky Mountain Laboratories in Hamilton, Mont, in an accompanying commentary (Feldmann H. Lancet. 2010;375[9729]:1850-1852). Feldmann added that improved outbreak support and providing specific care for affected individuals are needed, which means that promising experimental approaches to treating Ebola virus should be studied and “given at least approval as investigational new drugs that are ready to use in emergencies.”
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
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