Anti-Ebola tactic buys time for immune response

Research published this month suggests a new way of treating and preventing outbreaks of Africa's deadly Ebola virus, which can kill 50-90 per cent of infected people.

The study, in the January issue of PLoS Pathogens, claims to be the first report of a successful intervention against Ebola-like viruses in nonhuman primates that works by targeting the virus itself.

The team led by Sina Bavari of the US Army Medical Research Institute of Infectious Diseases says tests using the novel drug show it is possible to slow the replication of the virus. They think this gives the immune system more time to respond and fight infection.

The Ebola virus is deadly to both people and primates, such as gorillas and chimpanzees. It causes fever and severe internal bleeding.

Bavari's team tested their approach on mice and a small number of monkeys, meaning that many more studies must be done before this could become a practical treatment. 

Four monkeys were given the 'antisense' drug — strands of genetic material designed to interfere with the virus's production of the proteins it needs for replication — and infected Ebola.

Three monkeys survived, suggesting the treatment protected them from the virus, although one of these later died from a different infection.

"I think results are highly encouraging and demonstrate another strategy that could be used to counter Ebola-like viruses," says Tom Geisbert who is independently researching a vaccine against Ebola and the related Marburg virus at the same institute (see Ebola and Marburg vaccine '100% effective in monkeys').

Bavari's team gave the antisense drug both before and after they infected the monkeys with Ebola virus. Finding a successful treatment that could be given to people once they have been infected, has so far proven extremely difficult. 

"We look forward to seeing results of post-exposure treatments," adds Geisbert. "If they can demonstrate even 50 per cent success in post-exposure experiments, that would be significant."

Bavari says a treatment devised in this way could cost a few US dollars per dose, though several doses could be needed for protection.

Link to full paper in PLoS Pathogens

Reference: PLoS Pathogens 10/1371/jounal.ppat.0020001 (2006)