CDC Researchers Find Possible Animal Source for Marburg Virus

Scientists at the Centers for Disease Control and Prevention (CDC)and their collaborators have for the first time successfully identified Marburg virus infection in a common species of African fruit bat (Rousettus aegyptiacus). Marburg virus causes severe, often fatal, hemorrhagic fever in people and non-human primates. Bats have been suspected of carrying the virus, but until now, evidence of Marburg virus infection in bats had not been detected.  These research results were published Wednesday in the open access journal PLoS ONE.

"This groundbreaking discovery aids us in our efforts to combat a virus that causes very severe illness," said Julie Gerberding, MD, MPH, director of the CDC. "One of the challenges has been identifying how people get infected.  This research brings us closer to understanding the transmission of Marburg virus and hopefully will help advance our efforts to prevent or reduce the spread of the virus to people. There is much more that we need to learn about hemorrhagic fever viruses, but this is an important step forward."

The work, done in collaboration with the International Center for Medical Research (CIRMF) and the Institute for Research and Development, both in Franceville, Gabon, represents the first time in which Marburg virus genetic material and specific antibodies have both confirmed Marburg infection in a specific bat species.  There has been much speculation and scientific investigation of potential reservoirs for Marburg virus, but this is the first study to definitively document evidence of the virus in wild non-primates. It is also the first study to document evidence of Marburg virus in the Central African country of Gabon. 

In this study, more than1,100 bats representing 10 different species were tested. Only one species of African fruit bat (R. aegyptiacus), tested positive for Marburg virus infection.  No evidence of Marburg virus was identified in the other species of insect-eating or fruit bats tested. Further, viral genetic sequences obtained from the infected bats in this study were unique when compared to other known Marburg virus sequences from animals or humans. This species of African fruit bat is found throughout sub-Saharan Africa.

Marburg virus and the related Ebola virus have caused outbreaks of disease in both people and non-human primates (e.g., African green monkeys), and these outbreaks may result in the death of 80 to 90 percent of those infected.  With no vaccine or drug therapy available, outbreaks of Marburg often start abruptly and spread from person-to-person until infection control measures can be implemented. Reports of Marburg hemorrhagic fever are rare, with recent occurrences limited to countries in sub-Saharan Africa. 

The publication of this research coincides with a recent investigation of Marburg infection among miners in Uganda. CDC recently deployed a six-person team to investigate the source of the infection, help identify and find people who may have been exposed to the virus or to infected people, and offer guidance on infection control.  The team is also working to determine if the same bat species (R. aegyptiacus) or other species of bats might be the source of the infection among the Ugandan miners, and potential routes of transmission between the bats and humans.

"This recent discovery is helping to guide our current outbreak investigation in Uganda," said Dr. Jonathan Towner, lead author of the publication and a member of CDC's Ugandan investigation team.  "We're trapping bats that live in the mine to test them for evidence of Marburg virus infection.  If infected bats are found, we'll be looking at how they could have transmitted the virus to the miners."

Source: CDC