After months of official denial and obfuscation, it is finally being admitted that Ebola virus particles can be spread via aerosol droplets generated by sneezing or coughing, and can also survive on contaminated surfaces for several hours or days afterwards. According to the CDC:

"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."

"Healthcare teams should follow standard, contact, and droplet precautions... Avoid aerosol-generating procedures. If performing these procedures, PPE should include respiratory protection (N95 or higher filtering facepiece respirator) and the procedure should be performed in an airborne infection isolation room."

-- Source: "Safe Management of Patients with Ebola Virus Disease", U.S. Center for Disease Control (CDC)

Why does the CDC advise healthcare workers to use a "filtering respirator" and to avoid "aerosol generating procedures" except in a properly ventilated isolation room, while the general public (including the hapless victims in Africa) have been told repeatedly that the virus can only be transmitted by "direct contact" with an infected person?

"We believe there is scientific and epidemiologic evidence that Ebola virus has the potential to be transmitted via infectious aerosol particles both near and at a distance from infected patients, which means that healthcare workers should be wearing respirators, not facemasks... There has been a lot of on-line and published controversy about whether Ebola virus can be transmitted via aerosols...[which] reflects an incorrect and outmoded understanding of infectious aerosols."

-- Source: Center for Infectious Disease Research (CIDRAP), Univ of Michigan

Airline passengers and crew, who are confined in an enclosed space and breathing recirculated air for several hours, have reason for concern as demonstrated by computer models showing how aerosol particles are distributed in an aircraft cabin. The same concern applies to other types of public transportation or enclosed public spaces.

"The smaller droplets that emerge in a cough or sneeze may travel up to 200 times further than they would if those droplets simply moved as groups of unconnected particles -- which is what previous estimates had assumed. The tendency of these droplets to stay airborne, resuspended by gas clouds, means that ventilation systems may be more prone to transmitting potentially infectious particles than had been suspected."

-- Source: Massachusetts Institute of Technology

Meanwhile, the misinformed President Obama insists that travelling with an Ebola infected passenger is perfectly safe and still refuses to ban air travel from the afflicted regions. Why take the risk? Even the insurance companies are now excluding coverage for potential "business disruption" due to Ebola.

"If the filoviruses were aerosolized, either accidentally or as a deliberate release, it is also unknown how long they would survive as aerosols, and therefore how many people might potentially be exposed... Decay rates of a range of filoviruses, within small-particle aerosols, have been calculated, and these rates suggest that filoviruses are able to survive and remain infectious for cell culture for at least 90 minutes."

"Zaire ebolavirus (ZEBOV) can survive for long periods in different liquid media and can also be recovered from plastic and glass surfaces at low temperatures for over 3 weeks."

-- Source: Journal of Applied Microbiology, 2010-05-22

Air conditioning systems contain "surfaces at low temperatures" which could be contaminated by the drifting "small-particle aerosols" generated by the sneeze of an Ebola carrier. Likewise for the refrigerated display cases at the local grocery store. Even the cool, moist surfaces in a public restroom could conceivably sustain the virus for days.

The possibility also exists for "deliberate release" of the virus; sneezing is not required. Infected blood and tissue samples are readily available to any group willing to collect them, and the virus "can survive for long periods in different liquid media", especially at low temperatures. The raw material could be diluted many times, since it only takes a few of the microscopic virus particles to cause an infection, and the solution could easily be dispersed almost anywhere using a portable ultrasonic nebulizer or even a commercial haze generator. Yikes!

UPDATE: A more detailed discussion of this issue has been posted at Storm Clouds Gathering