Ebola: Disinfectants

I previously wrote about PPE for Ebola. Also critical in your preparedness place are disinfectants. They are used when:

  • Exiting a hot zone
  • Doffing (taking off) your PPE
  • Cleaning your gear
  • Disinfecting YOU
  • Cleaning structures, vehicles, bodies, and anything else potentially contaminated

The good news is that, Ebola, a virus, is relatively easy to kill.  Compared to cysts and bacteria, viruses are much more fragile and require much less contact time with a disinfecting agent in order to be effectively neutralized or inactivated.  The bad news is that there has been relatively little testing done on which specific disinfectants work against Ebola. Typically when you buy a medical disinfectant it will have a label on it that will specify what the disinfectant can successfully be used against.  At this point there is no disinfectant that has Ebola listed on its label, and there are only a handful of disinfectants that have been successfully tested against Ebola.

Back to good news again.  Ebola is relatively fragile; there are a number of viruses that are much harder to kill.  The current thinking in the medical community seems to be that, in the absence of solid testing information, to use a disinfectant that is rated for some of the more durable viruses, such as Norovirus or Rotovirus.  Basically, when it comes to killing Ebola, you can never have too much overkill. 

Now, the information below should be considered a starting point. Do some research of your own, and please only trust credible, medically knowledgeable sources. I'm not a doctor - take what I say with a grain of salt until you confirm it. But what I've assembled below is a list of chemicals that have scientific backing to support their effectiveness in killing Ebola.  

Chlorine

Chlorine is the most common disinfectant currently used in battling Ebola. You can buy it in liquid form from any grocery store as bleach or purchase dry Calcium Hypochlorite - try Pool supply stores for large quantities - or Amazon has 10 pounds for $29. It's mostly the dry form that is currently being used in Africa; UNICEF has 250,000 Kg of it on order, for example, for just the next six months. This is chemically equivalent to roughly 870,000 gallon jugs of household bleach. That would weigh something like 6.5 millions pounds; so, the dry stuff is way more economical to ship to Africa. The dry Calcium Hypochlorite is also much more stable for long term storage and is less volatile to ship.

For info on use and mixing of Calcium Hypochlorite look at this document.  The basics are these: if you have 60-70% powder, mix 10 ounces of the powder with 1 gallon of water. Stir, then let the sediment settle. Once it has, gentle scoop out the clear water. The water now has roughly 5% chlorine content. 

At 0.5% concentration, chlorine/bleach needs to come in contact with Ebola for at least 10 minutes to kill it. For use on people, use a 0.05% concentration. (Bleach is normally around 5% - so, dilute 1:10 or 1:100 to get the desired concentration)

Chlorhexidine Gluconate (CHG)

Hibiclens is a disinfectant/scrub solution. It works well on lipid viruses like Ebola, though it's not very effective against Norovirus, so it lacks the level of "over kill" we are trying to maintain. But it has the bonus of offering continued antibacterial effects for a further six hours after washing with it. A gallon of 4% solution costs about $70 on Amazon. A gallon of generic 2% for veterinarian use is a little over $20 shipped. A 0.2% solution will kill many viruses in less than a minute, so a 2% jug will last a long time.

At 0.2% concentration, wash for at least 60 seconds. Upping the concentration does improve performance, so consider taking it to 0.5% if you are actually facing Ebola.  
It also appears that mixing with Isopropyl Alcohol (0.5% Hibiclens + 70% Isopropyl Alcohol) improves performance - but research this before depending on it. Here's a starting point. 
 

Hydrogen Peroxide (H2o2)

Another option which seems to be effective is hydrogen peroxide. It’s used for Noro and Rotovirus (which are sometimes resistant to bleach) and can kill them in only a couple minutes. That means it should kill Ebola quickly also, but I never saw anything to indicate it had been successfully tested against Ebola.
H2o2 must be kept in airtight, dark containers. To dispense, screw a squeeze-sprayer top onto the bottle the peroxide comes in - they share thread patterns. This keeps the bottle sealed and makes dispensing much more efficient and economical.

3% Acetic Acid (vinegar)

As strange as it may sound, vinegar (as long as it has more than 3% acetic acid) works to inactivate Ebola. I couldn't find any information on what contact time is required, so I’d be cautious. Also, since you need a full 3% acetic acid, you probably can’t dilute your vinegar to make it go farther. There's not a lot of hard data on this out there, though, so use caution. Until more data becomes available, I'd only use vinegar on sensitive items and in conjunction with other agents of mechanisms, or if it was all I had available.  

Alcohol

Also considered effective against Ebola are alcohol based disinfectants - but it appears that you need at least 60% alcohol to be effective. More research is needed before this is adopted as a sole disinfectant.  

Physical Inactivation Methods

Ebola can also be killed with heat. Bake for an hour at 150 Fahrenheit or boil for 5 minutes.

UVC Light apparently is also moderately effective. This is very interesting, since bulbs are available for relatively cheap. $20-25 can get you a bulb that will screw into a regular light socket. I haven't yet researched how much exposure time is needed to inactivate Ebola. 

Conclusion

My personal plan is to use bleach for disinfecting large areas and to spray down PPE as part of the doffing process and to use my generic Hibiclens for handwashing, pre-treating gear, etc.