The U.S. Centers for Disease Control and Prevention will issue its second-highest level of travel notice for Rwanda, recommending people avoid nonessential travel due to the Marburg disease outbreak in the East African country, the U.S. government said on Monday.

The CDC will start screening for travellers entering the United States who have been in Rwanda in the past 21 days, the U.S. Department of Health and Human Services said.

Last week, the agency issued its "level 2" travel notice for Rwanda, urging enhanced precautions for those travelling to the country.

Rwanda's first outbreak of the Ebola-like disease was detected in late September, with 46 cases and 12 deaths reported since then. Marburg has a fatality rate as high as 88%.

It is transmitted to humans by fruit bats and then spreads through contact with the bodily fluids of infected individuals.

Rwanda has begun administering vaccine doses against the virus, prioritising the most at risk, most exposed healthcare workers, and the close contacts of the confirmed cases.