Two ongoing outbreaks of Marburg virus in Africa prompted U.S. health officials to issue an alert on Thursday for doctors to be on the lookout for any cases that might surface in the coming weeks.

The virus causes a deadly hemorrhagic disease that is similar to Ebola. The U.S. Centers for Disease Control and Prevention also plans to reach out to some travelers arriving in the United States after being in either Equatorial Guinea and Tanzania, the two countries where the outbreaks are happening.

"Currently, the risk of MVD [Marburg virus disease] in the United States is low; however, clinicians should be aware of the potential for imported cases. It is important to systematically assess patients for the possibility of viral hemorrhagic fevers," the CDC said in its alert.

The outbreak is among the largest in Africa in a decade, CBS News reported.

Authorities in Equatorial Guinea have identified 14 cases since Feb. 13. Ten people have died. Another 23 cases are probably caused by the virus, according to the World Health Organization.

The people infected don't have known links, so the virus may be spreading undetected.

"Though we do not know yet the origin of the Marburg outbreaks in Equatorial Guinea and Tanzania, we do know that there continues to be increased capacity in Africa to recognize and test samples for viral hemorrhagic fevers like Marburg and Ebola," the World Health Organization's Dr. Tieble Traore said Tuesday.

In Tanzania, five people have died in eight confirmed cases, according to the CDC.

The two outbreaks were likely separate, spreading from an animal host to a human and then between humans, the CDC added.

The CDC is texting travelers who have been in either of the two countries and asking them to call public health officials if they develop symptoms within 21 days of their return to the United States. There are no direct flights between those countries and the United States, CBS News reported.

"Currently, no enhanced domestic travel measures are recommended, as the overall risk in the United States is considered low at this time," the CDC alert said.

The United States is providing personal protective equipment and "technical support in epidemic management" in Tanzania, according to the White House.

CDC responders have also been deploying in Equatorial Guinea, including starting a lab on March 10 and training others in diagnosing Marburg, CBS News reported.

Symptoms for Marburg tend to start with fever and headaches anywhere between two days and three weeks after exposure, according to the CDC. They can build to include diarrhea, "massive hemorrhaging" and organ failure. About half of all patients die.

No approved vaccines exist for Marburg, but some may be available soon.

One option from the Sabin Vaccine Institute has 750 doses of experimental shots that could be used in trials for the outbreak, CBS News reported. They may be given to a "ring" of contacts of an infected person. That U.S. government-backed vaccine is based on a chimpanzee adenovirus.