What we know and don’t know about Ebola virus transmission in humans

Thursday, February 19, 2015

A new comprehensive analysis from the Center for Infectious Disease Research and Policy (CIDRAP) at the University of Minnesota, involving leading International Ebola researchers, examines what is known about transmission of the Ebola virus and cautions that the public health community should not rule out the possibility of respiratory transmission.

Prior to the current Ebola epidemic in West Africa there have been only 24 reported Ebola outbreaks with approximately 2,400 cases reported over the previous 39 years. Evidence suggests that direct patient contact and contact with infectious body fluids are the primary modes for Ebola virus transmission, however, this evidence is based on a limited number of studies.

The analysis was published today in mBio®, the online open-access journal of the American Society for Microbiology. 

The analysis further examines what we already know about the transmission of the Ebola virus and what we need to learn about its transmission. Due to the limitations of current data on Ebola virus cases, the role of aerosol transmission remains unclear. Transmission potentially occurs via virus-laden aerosols generated through the emission of body fluids during vomiting, diarrhea or coughing. It is advised that more studies are needed to better understand aerosol transmission in spreading the disease.

“Available evidence demonstrates that direct patient contact and contact with infectious body fluids are the primary modes for Ebola virus transmission, but this is based on a limited number of studies,” said Michael Osterholm, Ph.D., MPH, McKnight Presidential Endowed Chair in Public Health and director of CIDRAP and  lead author of the analysis. “In our comprehensive review, we address what we know and what we don’t know about Ebola virus transmission. We also hypothesize that based on the best scientific evidence, Ebola viruses have the potential to be respiratory pathogens with primary respiratory spread.”