Wednesday, June 29, 2005

Vaccine shields monkeys from Lassa fever

Last Updated Mon, 27 Jun 2005 21:01:30 EDT
CBC News
A vaccine successfully protected monkeys against Lassa fever, a sometimes deadly disease related to Ebola and Marburg, Canadian and U.S. scientists report.
Researchers are looking for a vaccine for Lassa, a hemorrhagic disease that kills an estimated 5,000 people a year in West Africa, according to the World Health Organization. The virus is carried by rodents and is endemic in the region.
There is no preventive medicine for the disease, which starts off flu-like and then can cause high fever and internal bleeding. Although 80 per cent of cases are considered mild, the virus is considered a potential bio-terrorism agent.
"While the mortality rate of this virus is not as high as with some viral hemorrhagic fevers, there are many more cases of Lassa fever and a great number of survivors are permanently affected by complications such as hearing loss," said Dr. Heinz Feldmann, chief of the special pathogens program at Canada's National Microbiology Laboratory in Winnipeg.
In this week's online issue of the journal PLoS Medicine, Feldmann and his co-authors describe tests of the made-in-Canada vaccine.
To make the prototype vaccine, researchers added genetic material from Lassa into a harmless form of another virus called vesicular stomatitis virus, or VSV.
Four rhesus macaques were injected with a single dose of the vaccine, and then experimentally infected with Lassa. The animals showed no evidence of clinical disease. Two control monkeys that were also infected with Lassa but received only the VSV component both died.
The Canadians and American research team has used the same technique to make and test vaccines for Ebola and Marsburg.
FROM : Vaccines protect monkeys from Ebola, Marburg: study
"This is the first vaccine platform shown to completely protect nonhuman primates from Lassa virus," said study co-author Thomas Geisbert of the U.S. Army Medical Research Institute of Infectious Diseases in Fort Detrick, Md. in a statement.
The researchers aim to vaccinate people at risk, as well to protect health-care who help to fight outbreaks and laboratory workers who work with virus. Travellers have also carried Lassa virus to the U.S. and Europe.
Before the vaccine can be tested in humans, more research is needed to make sure it is safe, find out how long it works and determine if it protects against other strains of Lassa virus.

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