A sudden outbreak of the deadly Ebola virus has killed 13 people in Uganda, according to the World Health Organization. The fatality rate for the virus is close to 90 percent, and there is no known cure. “There are a total of 20 people suspected to have contracted Ebola, and 13 of them have died,” said WHO representative Joaquim Saweka. Though an outbreak has been suspected since early in July, the cases were not verified until Friday. The cause for the sudden outbreak of the disease, which is spread by close contact between victims, has not yet been determined, Saweka said, and experts from the U.S. and WHO are investigating, he said.