Media Still Misstating Science on Ebola Transmission
This is the official dogma from The Dallas Morning News. It's wrong.
News media continue to present a picture of Ebola transmission that is significantly inaccurate by omission. They assert much more certainty than the science justifies. The version repeated like a mantra in most accounts -- only direct physical contact with an infectious person -- is wrong on its face and may be contributing to reduced vigilance.
What the science does say: direct physical contact with body fluids is the most common way and the most extensively documented way for the disease to travel. But science does not know that direct physical contact is the only way the disease can infect human beings. Scientists know the virus survives for significant periods of time outside the body, even dried on surfaces such as doorknobs and table tops. It is not known if a viable virus outside the body can infect a human being, because that research has not been done. But public health policy on decontamination assumes some risk, even if only at low levels, from so-called "environmental" (outside the body) Ebola virus.
A story in yesterday's Dallas Morning News by Seema Yasmin states as fact that, "There has to be direct contact with infected bodily fluids. Direct contact includes being within three feet of someone with Ebola who has symptoms of disease, because infectious droplets of saliva from a sneeze can travel that distance. The virus would have to pass through cuts or breaks in the skin or touch mucous membranes such as the insides of the mouth and nose or the eyes."
See also: Even the CDC Isn't Totally Sold on its Own Proclamations on How Ebola Is Transmitted
Another story in The Dallas Morning News today by Robert Wilonsky states that, "Ebola experts say that the illness can only be caught from contact with bodily fluids from someone ill with the virus."
A New York Times story today by Sabrina Tavernise says, "Ebola is one of the world's most lethal diseases, but is contagious only through contact with bodily fluids ..."
Those assurances simply are not supported by the science. A bulletin published this year by the Public Health Agency of Canada reports that Ebola virus is one of a family of viruses, called filoviruses, that "have been reported capable to survive for weeks in blood and can also survive on contaminated surfaces, particularly at low temperatures ..."
The same bulletin says, "There is also little known about how well filoviruses survive in liquids or on solid surfaces which is important in management of patients or samples that have been exposed to filoviruses."
The bulletin does not rule out infection from environmental virus. Instead it says, "A study on transmission of Ebola virus from fomites (surfaces) in an isolation ward concludes that the risk of transmission is low when recommended infection control guidelines for viral hemorrhagic fevers are followed."
An August 1, 2014, circular published by the U.S. Centers for Disease Control and Prevention is even more emphatic in stating that nobody knows if environmental virus can infect: "The role of the environment in transmission has not been established. Limited laboratory studies under favorable conditions indicate that Ebola virus can remain viable on solid surfaces, with concentrations falling slowly over several days."
Since early September, the CDC has been incrementally tweaking its own bulletins intended for the general public on the issue of transmission, slowly backing away from the initial mantra of transmission by direct physical contact only.
On September 9, the CDC was still saying, "The virus is spread through direct contact (through broken skin or mucous membranes) with a sick person's blood or body fluids (urine, saliva, feces, vomit and semen) (and) objects (such as needles) that have been contaminated with infected body fluids (or) infected animals."
On September 14 the CDC bulletin was revised to include transmission from handling or consumption of meat from game: "The virus is spread through direct contact (through broken skin or mucous membranes) with blood and body fluids (urine, feces, saliva, vomit and semen) of a person who is sick with Ebola, or with objects (like needles) that have been contaminated with the virus. Ebola is not spread through the air or by water or, in general, by food; however, in Africa, Ebola may be spread as a result of handling bushmeat (wild animals hunted for food) and contact with infected bats."
On September 22 the bulletin was revised again to include remarks on one of the most hotly debated of all transmission issues -- "aerosol" or transmission through air. The new version does not endorse aerosol transmission by free-floating viri, as with measles or flu, but it does suggest transmission by air if the virus is coated in a body fluid.
"Although coughing and sneezing are not common symptoms of Ebola, if a symptomatic patient with Ebola coughs or sneezes on someone, and saliva or mucus come into contact with that person's eyes, nose or mouth, these fluids may transmit the disease."
These incremental revisions all move in the same direction -- away from the strict doctrine of direct physical contact as the sole means of transmission. What if the public dogma on transmission were not "direct physical contact" with an infectious person only?
What if the statement sounded more like this:
Science knows that direct physical contact is the most common means of transmission, but science also knows the virus stays alive outside the body even on dried surfaces for hours or days. The ability of that environmental virus to infect a human being is unknown.
If that were the mantra -- basic knowledge but with appropriate scientifically justified caveats -- would nurses be less likely to rush into an isolation chamber with no protective coverings for their shoes, knowing those shoes might track environmental virus and that in removing those shoes later the nurses might be become infected?
Would sheriff's deputies be less likely to rush unprotected into the apartment of a known Ebola victim? Would a nurse who knew she might be infected be less likely to get on an airplane when she was already feeling sick?
Why would we continue to promulgate an abbreviated version of knowledge about transmission when the full version is right in front of us? Why do we prefer a version that minimizes even what is known and ignores what is not known?
Obviously the minimized version feels better. It sounds safer, less dangerous. How is that working out for us so far?
Some commenters below continue to assert there is no science to support transmission from surfaces. please see these two articles. Look for references to "fomites," science talk for surfaces.
I couldn't get the highlighting out of the first article, and it may actually blank out the important parts on your version of Scribd. If so, an early paragraph says:
"However, the source of infection remained unknown for 12 case-patients, which led to the suspicion that the virus was transmitted by airborne particles or fomites."
A concluding paragraph states:
"In fact one person in whom the disease developed was probably infected by contact with heavily infected fomites (patient 7) and many persons who had had a simple physical contact with a sick person did not become infected."
You can also find these articles here and here.
CDC (9-30-2014) (1) by Schutze
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