Health officials continue to monitor an outbreak of Marburg virus — also known as “bleeding eye virus” — in Rwanda, which has sparked concerns about a potential spread outside the country.

The U.S. State Department issued a travel advisory on Nov. 22, recommending that travelers exercise “increased caution” in Rwanda due to the outbreak.

“Travelers may be subject to additional health screenings [when] entering and exiting Rwanda,” the advisory stated. Similar to the Elbola virus, Marburg is a “rare but severe viral hemorrhagic fever” that is highly deadly, according to the Centers for Disease Control and Prevention (CDC). It has a 20% to 90% fatality rate.

The first case in Rwanda was confirmed in September. As of Nov. 29, the country had reported 66 cases of the virus and 15 deaths. Most of the infected people have been health care workers.

Approximately 75% of the patients with Marburg have recovered, according to the CDC.

There have not been any confirmed cases in the United States, and the CDC says the risk of infection in the country is low.

“Marburg is one of the deadliest viruses that infect humans,” Dr. Marc Siegel, senior medical analyst for Fox News and clinical professor of medicine at NYU Langone Medical Center, told Fox News Digital.

“It is very similar to Ebola in that it causes hemorrhagic fever.”

Initial symptoms usually mimic the flu, including fever, body aches, diarrhea, abdominal pain and vomiting.

The interval between infection and symptoms is typically two to 21 days, according to Siegel.