Thursday, February 19, 2015

mBio: Ebola Virus Transmission (What We Know, What We Don’t)




# 9729


The open access journal mBio has published an impressively detailed look at what we know about the transmission of the Ebola virus, penned by lead author Michael Osterholm of CIDRAP (along with an impressive international array of co-authors), that also asks a number of questions regarding what is not known about the virus.


Labeled as both an `Opinion’ piece, and a `Hypothesis’, this article also questions some of the assumptions about the behavior of the Ebola virus as it exists today, and as it might exist in the future.


Near the end of this paper you’ll find a clearly marked: RESPIRATORY TRANSMISSION OF EBOLA VIRUSES: A HYPOTHESIS, which asks the question:


Despite the lack of supportive epidemiological data, a key additional question to ask is whether primary pulmonary infections and respiratory transmission of Ebola viruses could be a potential scenario for the future.


Based on some twitter comments this morning, the inclusion of this hypothesis seems to have ruffled some academic feathers. Not being a virologist (or scientist of any stripe), I can’t really speak to the merits of their hypothesis, other than to say:


The path to new discoveries often lies in the willingness to continue to ask those questions that others already consider asked and answered.  


Whether you agree with their hypothesis (which they call `improbable’, but not impossible) or not, this review is well worth reading, and considering, in its entirety.  


Transmission of Ebola Viruses: What We Know and What We Do Not Know

Michael T. Osterholma, Kristine A. Moorea, Nicholas S. Kelleya, Lisa M. Brosseaub, Gary Wongc, Frederick A. Murphyd, Clarence J. Petersd, James W. LeDucd, Phillip K. Russelle, Michel Van Herpf, Jimmy Kapetshig, Jean-Jacques T. Muyembeg, Benoit Kebela Ilungah, James E. Strongc, Allen Grollac, Anja Wolzf, Brima Kargboi, David K. Kargboi, Pierre Formentyj, David Avram Sandersk, Gary P. Kobingerc



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. Key areas requiring further study include (i) the role of aerosol transmission (either via large droplets or small particles in the vicinity of source patients), (ii) the role of environmental contamination and fomite transmission, (iii) the degree to which minimally or mildly ill persons transmit infection, (iv) how long clinically relevant infectiousness persists, (v) the role that “superspreading events” may play in driving transmission dynamics, (vi) whether strain differences or repeated serial passage in outbreak settings can impact virus transmission, and (vii) what role sylvatic or domestic animals could play in outbreak propagation, particularly during major epidemics such as the 2013–2015 West Africa situation. In this review, we address what we know and what we do not know about Ebola virus transmission. We also hypothesize that Ebola viruses have the potential to be respiratory pathogens with primary respiratory spread.

(Continue . . . )

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