Researchers have found a way to make test monkeys totally resistant to the deadly Ebola virus, which normally has a 90% mortality rate, but there are limits to how it can be used to stop outbreaks.

Ebola epidemics are quite rare and limited to Central Africa, which is a boon, because the disease is extremely virulent and kills nine out of ten people infected in a matter of weeks. Its gruesome symptoms, which include bleeding, severe fever and vomiting, seem to come straight out of horror movies. So far no efficient treatment for the virus has been found.

However a new approach to fighting the virus, which has been long feared for its potential as a bioterror weapon, comes from the Boston University School of Medicine. Virologist Thomas Geisbert and colleagues used so-called small interfering RNAs (siRNA) to interfere with the virus’ replication. The molecules packed in special particles, which protect them from breaking down before reaching infected cells, were injected into test macaques shortly after their contamination with Ebola, they report in the medical journal Lancet.