Marburg virus causes an hemorrhagic fever, an extremely serious illness that is similar to Ebola and Lassa Fever. It is carried by fruit bats and is indigenous to Africa.The virus was discovered in the 1960s during work in a Marburg, Germany laboratory that resulted in an outbreak among lab workers - work conducted by global health agencies on outbreaks of the newly discovered hemorrhagic fevers in Africa.

A Colorado resident sought medical help in January after returning from a trip to Uganda and feeling ill. The Centers for Disease Control and Prevention (CDC) have confirmed that he is the first U.S. case of Marburg.

The cave he visited, and where he presumably caught the virus, has been closed following the death of a tourist from the Netherlands, also due to Marburg fever.

The hospital followed containment procedures outlined for unknown infections and has stated that any staff members concerned over their potential exposure can be tested. The hospital does not believe there should be any public worry of exposure because it is spread via body fluids.