Medical researchers have developed vaccines that appear to protect monkeys from the Ebola and Marburg viruses. The researchers say a single injection proved one hundred percent effective.

Scientists from the Public Health Agency of Canada developed the vaccines. They had assistance from researchers at the United States Army Medical Research Institute of Infectious Diseases. The study appeared in Nature Medicine.

The researchers say the study with twelve macaque monkeys suggests that the vaccines might also be able to protect people. Ebola and Marburg are always deadly to monkeys and other non-human primates. In humans, the viruses can kill eighty to ninety percent of those who become infected.

A recent outbreak of Marburg in Angola has killed more then three hundred fifty people. Vaccines could help prevent outbreaks. They could also be used in case of biological terrorism.

The researchers took one gene from the Ebola or Marburg virus and placed it into another virus to use in the experimental vaccines. They say the vaccine itself cannot cause disease. But it does cause the body to react in a way that would protect people if they ever really became infected with Ebola or Marburg.

Ebola and Marburg are spread through bodily fluids. Both diseases cause high temperatures, organ failure and severe bleeding. There are no cures.

Both viruses spread from time to time in central Africa. Scientists recorded the first Ebola outbreak in nineteen seventy-six in Zaire, now the Democratic Republic of Congo. Laboratories in Europe first recognized Marburg virus in monkeys in nineteen sixty-seven.

The vaccines must go through several years of testing before they can be approved for human use.

If so, they could be included one day in a program to vaccinate millions of people against deadly diseases. Members of the World Health Organization approved a Global Immunization Strategy at a meeting in Geneva in May. The aim is to expand vaccination programs.

Vaccine-preventable diseases kill more than two million people per year, mostly children. One goal of the new policy is to reach at least eighty percent vaccination coverage in every area of a country by two thousand ten.

This VOA Special English Development Report was written by Jill Moss. Our reports are on the Web at WWW.51VOA.COM. I'm Gwen Outen.