Amid an outbreak of Marburg virus in Rwanda, travelers coming into the United States who have been in Rwanda in the previous 21 days will be screened starting next week, the US Department of Health and Human Services announced Monday.

U.S. health officials are preparing to screen passengers flying in from Rwanda for symptoms of Marburg virus, a severe infection similar to Ebola.

Rwanda has said it will begin vaccine trials for the fatal Marburg virus, which has already killed at least 12 people in the country - most of them health workers. The east African country has received 700 doses of the vaccine from the Sabin Vaccine Institute, a US-based non-profit organisation.