by NoOneImportant » Tue Sep 09, 2014 10:59 pm
Regarding something as volatile as Ebola it is difficult to get definitive answers. While I am certainly not "the source" for information regarding Ebola we can reference definitive research and get reasonably close to definite answers. The quotes noted below come from the Public Health Agency of Canada dated 8/22/2014 - apparently one of the best research sources, as the American CDC documents, regarding Ebola, reference this Canadian document -
http://www.phac-aspc.gc.ca/lab-bio/res/ ... la-eng.php.
The Public Health Agency of Canada (PHAC) 8/22/2014 wrote:
MODE OF TRANSMISSION:
In an outbreak, it is hypothesized that the first patient becomes infected as a result of contact with an infected animal Footnote 22. Person-to-person transmission occurs via close personal contact with an infected individual or their body fluids during the late stages of infection or after death Footnote 1 Footnote 2 Footnote 22 Footnote 42. Nosocomial (hospital acquired) infections can occur through contact with infected body fluids for example due to the reuse of unsterilized syringes, needles, or other medical equipment contaminated with these fluids Footnote 1 Footnote 2. Humans may be infected by handling sick or dead non-human primates and are also at risk when handling the bodies of deceased humans in preparation for funerals Footnote 2 Footnote 10 Footnote 43.
In laboratory settings, non-human primates exposed to aerosolized ebolavirus from pigs have become infected, however, airborne transmission has not been demonstrated between non-human primates Footnote 1 Footnote 10 Footnote 15 Footnote 44 Footnote 45. Viral shedding has been observed in nasopharyngeal (nasal) secretions and rectal swabs of pigs following experimental inoculation Footnote 29 Footnote 30.
INCUBATION PERIOD: Two to 21 days Footnote 1 Footnote 15 Footnote 17.
COMMUNICABILITY: Communicable as long as blood, body fluids or organs, contain the virus. Ebolavirus has been isolated from semen 61 to 82 days after the onset of illness, and transmission through semen has occurred 7 weeks after clinical recovery Footnote 1 Footnote 2 Footnote 59 Footnote 60.
While the jury may still be out regarding whether Ebola may be spread from human to human via airborne aerosol or whether it may not. As Gerald noted in his post, what is not in doubt is that in a lab environment, using animal test subjects, Ebola is transmitted via an Ebola contaminated aerosol from infected animals of one species to subject primate test animals.
http://www.phac-aspc.gc.ca/lab-bio/res/ ... la-eng.php
What is unquestionable is that the Ebola virus does not die immediately with the patient. As John noted in his post, it is most commonly transmitted by close physical contact with the bodily fluids of those who are exhibiting active Ebola symptoms, or by touching, without protection, the bodies of those who have died of the Ebola virus. Also of note is that a recovered patient male patient may exhibit viable Ebola virus in his semen for up to 7 weeks after his "recovery." Said male patients remain capable of infecting anyone with who he has intercourse during that 7 week period of time.
What is also apparent is that, given a sufficient external environment, Ebola can remain viable for an extended period of time at ambient (room) temperatures, and for longer periods the lower the ambient temperature - up to 50 days at 4 degrees C, or in excess of 15 hours at room temperature. In that regard all items -- seats, sheets, arm rests, beds, clothing, all human liquid excretions, et al -- touched by an active Ebola patient may be considered to be sufficient to transmit an active infection. The following is, again, taken from the Public Health Agency of Canada (PHAC) fact sheet on Ebola dated 8/22/2014 (the current outbreak has been identified as one of the five most virulent strains -- Zire Ebola (ZEBOV)).
The Public Health Agency of Canada (PHAC) -- 8/22/2014 -- wrote:
SUSCEPTIBILITY TO DISINFECTANTS:
Ebolavirus is susceptible to 3% acetic acid, 1% glutaraldehyde, alcohol-based products, and dilutions (1:10-1:100 for ≥10 minutes) of 5.25% household bleach (sodium hypochlorite), and calcium hypochlorite (bleach powder) Footnote 48 Footnote 49 Footnote 50 Footnote 62 Footnote 63. The WHO recommendations for cleaning up spills of blood or body fluids suggest flooding the area with a 1:10 dilutions of 5.25% household bleach for 10 minutes for surfaces that can tolerate stronger bleach solutions (e.g., cement, metal) Footnote 62. For surfaces that may corrode or discolour, they recommend careful cleaning to remove visible stains followed by contact with a 1:100 dilution of 5.25% household bleach for more than 10 minutes.
The take away is that anything touched by an active patient, or his bodily fluids may be disinfected with acetic acid 3% (vinegar, be sure to check the lable for acetic acid concentration, white vinegar is usu 5% acetic acid), alcohol, and bleach solutions, but the solution must be given time -- 10 minutes -- to perform its disinfecting action. To that end, a simple wipe of a prospectively infected item with a disinfecting solution is not sufficient to provide disinfection. (Ref. PHAC footnote #61) Research published in 2010 indicated viable ZEBOV virus may be found on glass, and plastic surfaces up to 3 weeks after deposition. The lower the temperature, the longer the "sample" will remain viable. An abstract,with a link to the .pdf of the full paper may be found at PubMed --
http://www.ncbi.nlm.nih.gov/pubmed/20553340
The prevailing wisdom is: so long as you do not touch the bodily fluids of an actively sick patient you are safe from infection. While that is the prevailing wisdom, the item above indicates that indirect infection is not just possible, but likely (my interpretation). Like the flu, a virus that the Ebola emulates early on, apparently Ebola may be transmitted by contaminated, un-disinfected material items routinely found in the environment (by door knobs, faucet fixtures, hand rails, and other commonplace items), items that a sweating, or contaminated infected hand may have deposit a culture of the active virus -- thus are all personal items of Ebola infected patients burned in Africa (according to news articles, no reference cited).
The PHAC 8/22/2014 wrote:
SURVIVAL OUTSIDE HOST:
Filoviruses (Ebola) have been reported capable to survive for weeks in blood and can also survive on contaminated surfaces, particularly at low temperatures (4°C) Footnote 52 Footnote 61. One study could not recover any Ebolavirus from experimentally contaminated surfaces (plastic, metal or glass) at room temperature Footnote 61. In another study, Ebolavirus dried onto glass, polymeric silicone rubber, or painted aluminum alloy is able to survive in the dark for several hours under ambient conditions (between 20 and 250C and 30–40% relative humidity) (amount of virus reduced to 37% after 15.4 hours), but is less stable than some other viral hemorrhagic fevers (Lassa) Footnote 53. When dried in tissue culture media onto glass and stored at 4 °C, Zaire ebolavirus survived for over 50 days Footnote 61. This information is based on experimental findings only and not based on observations in nature. This information is intended to be used to support local risk assessments in a laboratory setting.
A study on transmission of ebolavirus from fomites (bedding, and clothing) in an isolation ward concludes that the risk of transmission is low when recommended infection control guidelines for viral hemorrhagic fevers are followed Footnote 64. Infection control protocols included decontamination of floors with 0.5% bleach daily and decontamination of visibly contaminated surfaces with 0.05% bleach as necessary.
Regarding something as volatile as Ebola it is difficult to get definitive answers. While I am certainly not "the source" for information regarding Ebola we can reference definitive research and get reasonably close to definite answers. The quotes noted below come from the Public Health Agency of Canada dated 8/22/2014 - apparently one of the best research sources, as the American CDC documents, regarding Ebola, reference this Canadian document - http://www.phac-aspc.gc.ca/lab-bio/res/psds-ftss/ebola-eng.php.
The Public Health Agency of Canada (PHAC) 8/22/2014 wrote:
[quote]MODE OF TRANSMISSION:
In an outbreak, it is hypothesized that the first patient becomes infected as a result of contact with an infected animal Footnote 22. Person-to-person transmission occurs via close personal contact with an infected individual or their body fluids during the late stages of infection or after death Footnote 1 Footnote 2 Footnote 22 Footnote 42. Nosocomial (hospital acquired) infections can occur through contact with infected body fluids for example due to the reuse of unsterilized syringes, needles, or other medical equipment contaminated with these fluids Footnote 1 Footnote 2. Humans may be infected by handling sick or dead non-human primates and are also at risk when handling the bodies of deceased humans in preparation for funerals Footnote 2 Footnote 10 Footnote 43.
In laboratory settings, non-human primates exposed to aerosolized ebolavirus from pigs have become infected, however, airborne transmission has not been demonstrated between non-human primates Footnote 1 Footnote 10 Footnote 15 Footnote 44 Footnote 45. Viral shedding has been observed in nasopharyngeal (nasal) secretions and rectal swabs of pigs following experimental inoculation Footnote 29 Footnote 30.
INCUBATION PERIOD: Two to 21 days Footnote 1 Footnote 15 Footnote 17.
COMMUNICABILITY: Communicable as long as blood, body fluids or organs, contain the virus. Ebolavirus has been isolated from semen 61 to 82 days after the onset of illness, and transmission through semen has occurred 7 weeks after clinical recovery Footnote 1 Footnote 2 Footnote 59 Footnote 60.[/quote]
While the jury may still be out regarding whether Ebola may be spread from human to human via airborne aerosol or whether it may not. As Gerald noted in his post, what is not in doubt is that in a lab environment, using animal test subjects, Ebola is transmitted via an Ebola contaminated aerosol from infected animals of one species to subject primate test animals. http://www.phac-aspc.gc.ca/lab-bio/res/psds-ftss/ebola-eng.php
What is unquestionable is that the Ebola virus does not die immediately with the patient. As John noted in his post, it is most commonly transmitted by close physical contact with the bodily fluids of those who are exhibiting active Ebola symptoms, or by touching, without protection, the bodies of those who have died of the Ebola virus. Also of note is that a recovered patient male patient may exhibit viable Ebola virus in his semen for up to 7 weeks after his "recovery." Said male patients remain capable of infecting anyone with who he has intercourse during that 7 week period of time.
What is also apparent is that, given a sufficient external environment, Ebola can remain viable for an extended period of time at ambient (room) temperatures, and for longer periods the lower the ambient temperature - up to 50 days at 4 degrees C, or in excess of 15 hours at room temperature. In that regard all items -- seats, sheets, arm rests, beds, clothing, all human liquid excretions, et al -- touched by an active Ebola patient may be considered to be sufficient to transmit an active infection. The following is, again, taken from the Public Health Agency of Canada (PHAC) fact sheet on Ebola dated 8/22/2014 (the current outbreak has been identified as one of the five most virulent strains -- Zire Ebola (ZEBOV)).
The Public Health Agency of Canada (PHAC) -- 8/22/2014 -- wrote:
[quote]SUSCEPTIBILITY TO DISINFECTANTS:
Ebolavirus is susceptible to 3% acetic acid, 1% glutaraldehyde, alcohol-based products, and dilutions (1:10-1:100 for ≥10 minutes) of 5.25% household bleach (sodium hypochlorite), and calcium hypochlorite (bleach powder) Footnote 48 Footnote 49 Footnote 50 Footnote 62 Footnote 63. The WHO recommendations for cleaning up spills of blood or body fluids suggest flooding the area with a 1:10 dilutions of 5.25% household bleach for 10 minutes for surfaces that can tolerate stronger bleach solutions (e.g., cement, metal) Footnote 62. For surfaces that may corrode or discolour, they recommend careful cleaning to remove visible stains followed by contact with a 1:100 dilution of 5.25% household bleach for more than 10 minutes.[/quote]
The take away is that anything touched by an active patient, or his bodily fluids may be disinfected with acetic acid 3% (vinegar, be sure to check the lable for acetic acid concentration, white vinegar is usu 5% acetic acid), alcohol, and bleach solutions, but the solution must be given time -- 10 minutes -- to perform its disinfecting action. To that end, a simple wipe of a prospectively infected item with a disinfecting solution is not sufficient to provide disinfection. (Ref. PHAC footnote #61) Research published in 2010 indicated viable ZEBOV virus may be found on glass, and plastic surfaces up to 3 weeks after deposition. The lower the temperature, the longer the "sample" will remain viable. An abstract,with a link to the .pdf of the full paper may be found at PubMed -- http://www.ncbi.nlm.nih.gov/pubmed/20553340
The prevailing wisdom is: so long as you do not touch the bodily fluids of an actively sick patient you are safe from infection. While that is the prevailing wisdom, the item above indicates that indirect infection is not just possible, but likely (my interpretation). Like the flu, a virus that the Ebola emulates early on, apparently Ebola may be transmitted by contaminated, un-disinfected material items routinely found in the environment (by door knobs, faucet fixtures, hand rails, and other commonplace items), items that a sweating, or contaminated infected hand may have deposit a culture of the active virus -- thus are all personal items of Ebola infected patients burned in Africa (according to news articles, no reference cited).
The PHAC 8/22/2014 wrote:
[quote]SURVIVAL OUTSIDE HOST:
Filoviruses (Ebola) have been reported capable to survive for weeks in blood and can also survive on contaminated surfaces, particularly at low temperatures (4°C) Footnote 52 Footnote 61. One study could not recover any Ebolavirus from experimentally contaminated surfaces (plastic, metal or glass) at room temperature Footnote 61. In another study, Ebolavirus dried onto glass, polymeric silicone rubber, or painted aluminum alloy is able to survive in the dark for several hours under ambient conditions (between 20 and 250C and 30–40% relative humidity) (amount of virus reduced to 37% after 15.4 hours), but is less stable than some other viral hemorrhagic fevers (Lassa) Footnote 53. When dried in tissue culture media onto glass and stored at 4 °C, Zaire ebolavirus survived for over 50 days Footnote 61. This information is based on experimental findings only and not based on observations in nature. This information is intended to be used to support local risk assessments in a laboratory setting.
A study on transmission of ebolavirus from fomites (bedding, and clothing) in an isolation ward concludes that the risk of transmission is low when recommended infection control guidelines for viral hemorrhagic fevers are followed Footnote 64. Infection control protocols included decontamination of floors with 0.5% bleach daily and decontamination of visibly contaminated surfaces with 0.05% bleach as necessary.[/quote]